text: /*
   * Copyright 2016-2021 The Brenwill Workshop Ltd.
   * SPDX-License-Identifier: Apache-2.0 OR MIT
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  /*
   * At your option, you may choose to accept this material under either:
   *  1. The Apache License, Version 2.0, found at <http://www.apache.org/licenses/LICENSE-2.0>, or
   *  2. The MIT License, found at <http://opensource.org/licenses/MIT>.
   */
  
  #include "spirv_msl.hpp"
  #include "GLSL.std.450.h"
  
  #include <algorithm>
  #include <assert.h>
  #include <numeric>
  
  using namespace spv;
  using namespace SPIRV_CROSS_NAMESPACE;
  using namespace std;
  
  static const uint32_t k_unknown_location = ~0u;
  static const uint32_t k_unknown_component = ~0u;
  static const char *force_inline = "static inline __attribute__((always_inline))";
  
  CompilerMSL::CompilerMSL(std::vector<uint32_t> spirv_)
      : CompilerGLSL(move(spirv_))
  {
  }
  
  CompilerMSL::CompilerMSL(const uint32_t *ir_, size_t word_count)
      : CompilerGLSL(ir_, word_count)
  {
  }
  
  CompilerMSL::CompilerMSL(const ParsedIR &ir_)
      : CompilerGLSL(ir_)
  {
  }
  
  CompilerMSL::CompilerMSL(ParsedIR &&ir_)
      : CompilerGLSL(std::move(ir_))
  {
  }
  
  void CompilerMSL::add_msl_shader_input(const MSLShaderInput &si)
  {
  	inputs_by_location[si.location] = si;
  	if (si.builtin != BuiltInMax && !inputs_by_builtin.count(si.builtin))
  		inputs_by_builtin[si.builtin] = si;
  }
  
  void CompilerMSL::add_msl_resource_binding(const MSLResourceBinding &binding)
  {
  	StageSetBinding tuple = { binding.stage, binding.desc_set, binding.binding };
  	resource_bindings[tuple] = { binding, false };
  
  	// If we might need to pad argument buffer members to positionally align
  	// arg buffer indexes, also maintain a lookup by argument buffer index.
  	if (msl_options.pad_argument_buffer_resources)
  	{
  		StageSetBinding arg_idx_tuple = { binding.stage, binding.desc_set, k_unknown_component };
  
  #define ADD_ARG_IDX_TO_BINDING_NUM_LOOKUP(rez) \
  	arg_idx_tuple.binding = binding.msl_##rez; \
  	resource_arg_buff_idx_to_binding_number[arg_idx_tuple] = binding.binding
  
  		switch (binding.basetype)
  		{
  		case SPIRType::Void:
  		case SPIRType::Boolean:
  		case SPIRType::SByte:
  		case SPIRType::UByte:
  		case SPIRType::Short:
  		case SPIRType::UShort:
  		case SPIRType::Int:
  		case SPIRType::UInt:
  		case SPIRType::Int64:
  		case SPIRType::UInt64:
  		case SPIRType::AtomicCounter:
  		case SPIRType::Half:
  		case SPIRType::Float:
  		case SPIRType::Double:
  			ADD_ARG_IDX_TO_BINDING_NUM_LOOKUP(buffer);
  			break;
  		case SPIRType::Image:
  			ADD_ARG_IDX_TO_BINDING_NUM_LOOKUP(texture);
  			break;
  		case SPIRType::Sampler:
  			ADD_ARG_IDX_TO_BINDING_NUM_LOOKUP(sampler);
  			break;
  		case SPIRType::SampledImage:
  			ADD_ARG_IDX_TO_BINDING_NUM_LOOKUP(texture);
  			ADD_ARG_IDX_TO_BINDING_NUM_LOOKUP(sampler);
  			break;
  		default:
  			SPIRV_CROSS_THROW("Unexpected argument buffer resource base type. When padding argument buffer elements, "
  			                  "all descriptor set resources must be supplied with a base type by the app.");
  		}
  #undef ADD_ARG_IDX_TO_BINDING_NUM_LOOKUP
  	}
  }
  
  void CompilerMSL::add_dynamic_buffer(uint32_t desc_set, uint32_t binding, uint32_t index)
  {
  	SetBindingPair pair = { desc_set, binding };
  	buffers_requiring_dynamic_offset[pair] = { index, 0 };
  }
  
  void CompilerMSL::add_inline_uniform_block(uint32_t desc_set, uint32_t binding)
  {
  	SetBindingPair pair = { desc_set, binding };
  	inline_uniform_blocks.insert(pair);
  }
  
  void CompilerMSL::add_discrete_descriptor_set(uint32_t desc_set)
  {
  	if (desc_set < kMaxArgumentBuffers)
  		argument_buffer_discrete_mask |= 1u << desc_set;
  }
  
  void CompilerMSL::set_argument_buffer_device_address_space(uint32_t desc_set, bool device_storage)
  {
  	if (desc_set < kMaxArgumentBuffers)
  	{
  		if (device_storage)
  			argument_buffer_device_storage_mask |= 1u << desc_set;
  		else
  			argument_buffer_device_storage_mask &= ~(1u << desc_set);
  	}
  }
  
  bool CompilerMSL::is_msl_shader_input_used(uint32_t location)
  {
  	// Don't report internal location allocations to app.
  	return location_inputs_in_use.count(location) != 0 &&
  	       location_inputs_in_use_fallback.count(location) == 0;
  }
  
  uint32_t CompilerMSL::get_automatic_builtin_input_location(spv::BuiltIn builtin) const
  {
  	auto itr = builtin_to_automatic_input_location.find(builtin);
  	if (itr == builtin_to_automatic_input_location.end())
  		return k_unknown_location;
  	else
  		return itr->second;
  }
  
  bool CompilerMSL::is_msl_resource_binding_used(ExecutionModel model, uint32_t desc_set, uint32_t binding) const
  {
  	StageSetBinding tuple = { model, desc_set, binding };
  	auto itr = resource_bindings.find(tuple);
  	return itr != end(resource_bindings) && itr->second.second;
  }
  
  // Returns the size of the array of resources used by the variable with the specified id.
  // The returned value is retrieved from the resource binding added using add_msl_resource_binding().
  uint32_t CompilerMSL::get_resource_array_size(uint32_t id) const
  {
  	StageSetBinding tuple = { get_entry_point().model, get_decoration(id, DecorationDescriptorSet),
  		                      get_decoration(id, DecorationBinding) };
  	auto itr = resource_bindings.find(tuple);
  	return itr != end(resource_bindings) ? itr->second.first.count : 0;
  }
  
  uint32_t CompilerMSL::get_automatic_msl_resource_binding(uint32_t id) const
  {
  	return get_extended_decoration(id, SPIRVCrossDecorationResourceIndexPrimary);
  }
  
  uint32_t CompilerMSL::get_automatic_msl_resource_binding_secondary(uint32_t id) const
  {
  	return get_extended_decoration(id, SPIRVCrossDecorationResourceIndexSecondary);
  }
  
  uint32_t CompilerMSL::get_automatic_msl_resource_binding_tertiary(uint32_t id) const
  {
  	return get_extended_decoration(id, SPIRVCrossDecorationResourceIndexTertiary);
  }
  
  uint32_t CompilerMSL::get_automatic_msl_resource_binding_quaternary(uint32_t id) const
  {
  	return get_extended_decoration(id, SPIRVCrossDecorationResourceIndexQuaternary);
  }
  
  void CompilerMSL::set_fragment_output_components(uint32_t location, uint32_t components)
  {
  	fragment_output_components[location] = components;
  }
  
  bool CompilerMSL::builtin_translates_to_nonarray(spv::BuiltIn builtin) const
  {
  	return (builtin == BuiltInSampleMask);
  }
  
  void CompilerMSL::build_implicit_builtins()
  {
  	bool need_sample_pos = active_input_builtins.get(BuiltInSamplePosition);
  	bool need_vertex_params = capture_output_to_buffer && get_execution_model() == ExecutionModelVertex &&
  	                          !msl_options.vertex_for_tessellation;
  	bool need_tesc_params = get_execution_model() == ExecutionModelTessellationControl;
  	bool need_subgroup_mask =
  	    active_input_builtins.get(BuiltInSubgroupEqMask) || active_input_builtins.get(BuiltInSubgroupGeMask) ||
  	    active_input_builtins.get(BuiltInSubgroupGtMask) || active_input_builtins.get(BuiltInSubgroupLeMask) ||
  	    active_input_builtins.get(BuiltInSubgroupLtMask);
  	bool need_subgroup_ge_mask = !msl_options.is_ios() && (active_input_builtins.get(BuiltInSubgroupGeMask) ||
  	                                                       active_input_builtins.get(BuiltInSubgroupGtMask));
  	bool need_multiview = get_execution_model() == ExecutionModelVertex && !msl_options.view_index_from_device_index &&
  	                      msl_options.multiview_layered_rendering &&
  	                      (msl_options.multiview || active_input_builtins.get(BuiltInViewIndex));
  	bool need_dispatch_base =
  	    msl_options.dispatch_base && get_execution_model() == ExecutionModelGLCompute &&
  	    (active_input_builtins.get(BuiltInWorkgroupId) || active_input_builtins.get(BuiltInGlobalInvocationId));
  	bool need_grid_params = get_execution_model() == ExecutionModelVertex && msl_options.vertex_for_tessellation;
  	bool need_vertex_base_params =
  	    need_grid_params &&
  	    (active_input_builtins.get(BuiltInVertexId) || active_input_builtins.get(BuiltInVertexIndex) ||
  	     active_input_builtins.get(BuiltInBaseVertex) || active_input_builtins.get(BuiltInInstanceId) ||
  	     active_input_builtins.get(BuiltInInstanceIndex) || active_input_builtins.get(BuiltInBaseInstance));
  	bool need_local_invocation_index = msl_options.emulate_subgroups && active_input_builtins.get(BuiltInSubgroupId);
  	bool need_workgroup_size = msl_options.emulate_subgroups && active_input_builtins.get(BuiltInNumSubgroups);
  
  	if (need_subpass_input || need_sample_pos || need_subgroup_mask || need_vertex_params || need_tesc_params ||
  	    need_multiview || need_dispatch_base || need_vertex_base_params || need_grid_params || needs_sample_id ||
  	    needs_subgroup_invocation_id || needs_subgroup_size || has_additional_fixed_sample_mask() || need_local_invocation_index ||
  	    need_workgroup_size)
  	{
  		bool has_frag_coord = false;
  		bool has_sample_id = false;
  		bool has_vertex_idx = false;
  		bool has_base_vertex = false;
  		bool has_instance_idx = false;
  		bool has_base_instance = false;
  		bool has_invocation_id = false;
  		bool has_primitive_id = false;
  		bool has_subgroup_invocation_id = false;
  		bool has_subgroup_size = false;
  		bool has_view_idx = false;
  		bool has_layer = false;
  		bool has_local_invocation_index = false;
  		bool has_workgroup_size = false;
  		uint32_t workgroup_id_type = 0;
  
  		ir.for_each_typed_id<SPIRVariable>([&](uint32_t, SPIRVariable &var) {
  			if (var.storage != StorageClassInput && var.storage != StorageClassOutput)
  				return;
  			if (!interface_variable_exists_in_entry_point(var.self))
  				return;
  			if (!has_decoration(var.self, DecorationBuiltIn))
  				return;
  
  			BuiltIn builtin = ir.meta[var.self].decoration.builtin_type;
  
  			if (var.storage == StorageClassOutput)
  			{
  				if (has_additional_fixed_sample_mask() && builtin == BuiltInSampleMask)
  				{
  					builtin_sample_mask_id = var.self;
  					mark_implicit_builtin(StorageClassOutput, BuiltInSampleMask, var.self);
  					does_shader_write_sample_mask = true;
  				}
  			}
  
  			if (var.storage != StorageClassInput)
  				return;
  
  			// Use Metal's native frame-buffer fetch API for subpass inputs.
  			if (need_subpass_input && (!msl_options.use_framebuffer_fetch_subpasses))
  			{
  				switch (builtin)
  				{
  				case BuiltInFragCoord:
  					mark_implicit_builtin(StorageClassInput, BuiltInFragCoord, var.self);
  					builtin_frag_coord_id = var.self;
  					has_frag_coord = true;
  					break;
  				case BuiltInLayer:
  					if (!msl_options.arrayed_subpass_input || msl_options.multiview)
  						break;
  					mark_implicit_builtin(StorageClassInput, BuiltInLayer, var.self);
  					builtin_layer_id = var.self;
  					has_layer = true;
  					break;
  				case BuiltInViewIndex:
  					if (!msl_options.multiview)
  						break;
  					mark_implicit_builtin(StorageClassInput, BuiltInViewIndex, var.self);
  					builtin_view_idx_id = var.self;
  					has_view_idx = true;
  					break;
  				default:
  					break;
  				}
  			}
  
  			if ((need_sample_pos || needs_sample_id) && builtin == BuiltInSampleId)
  			{
  				builtin_sample_id_id = var.self;
  				mark_implicit_builtin(StorageClassInput, BuiltInSampleId, var.self);
  				has_sample_id = true;
  			}
  
  			if (need_vertex_params)
  			{
  				switch (builtin)
  				{
  				case BuiltInVertexIndex:
  					builtin_vertex_idx_id = var.self;
  					mark_implicit_builtin(StorageClassInput, BuiltInVertexIndex, var.self);
  					has_vertex_idx = true;
  					break;
  				case BuiltInBaseVertex:
  					builtin_base_vertex_id = var.self;
  					mark_implicit_builtin(StorageClassInput, BuiltInBaseVertex, var.self);
  					has_base_vertex = true;
  					break;
  				case BuiltInInstanceIndex:
  					builtin_instance_idx_id = var.self;
  					mark_implicit_builtin(StorageClassInput, BuiltInInstanceIndex, var.self);
  					has_instance_idx = true;
  					break;
  				case BuiltInBaseInstance:
  					builtin_base_instance_id = var.self;
  					mark_implicit_builtin(StorageClassInput, BuiltInBaseInstance, var.self);
  					has_base_instance = true;
  					break;
  				default:
  					break;
  				}
  			}
  
  			if (need_tesc_params)
  			{
  				switch (builtin)
  				{
  				case BuiltInInvocationId:
  					builtin_invocation_id_id = var.self;
  					mark_implicit_builtin(StorageClassInput, BuiltInInvocationId, var.self);
  					has_invocation_id = true;
  					break;
  				case BuiltInPrimitiveId:
  					builtin_primitive_id_id = var.self;
  					mark_implicit_builtin(StorageClassInput, BuiltInPrimitiveId, var.self);
  					has_primitive_id = true;
  					break;
  				default:
  					break;
  				}
  			}
  
  			if ((need_subgroup_mask || needs_subgroup_invocation_id) && builtin == BuiltInSubgroupLocalInvocationId)
  			{
  				builtin_subgroup_invocation_id_id = var.self;
  				mark_implicit_builtin(StorageClassInput, BuiltInSubgroupLocalInvocationId, var.self);
  				has_subgroup_invocation_id = true;
  			}
  
  			if ((need_subgroup_ge_mask || needs_subgroup_size) && builtin == BuiltInSubgroupSize)
  			{
  				builtin_subgroup_size_id = var.self;
  				mark_implicit_builtin(StorageClassInput, BuiltInSubgroupSize, var.self);
  				has_subgroup_size = true;
  			}
  
  			if (need_multiview)
  			{
  				switch (builtin)
  				{
  				case BuiltInInstanceIndex:
  					// The view index here is derived from the instance index.
  					builtin_instance_idx_id = var.self;
  					mark_implicit_builtin(StorageClassInput, BuiltInInstanceIndex, var.self);
  					has_instance_idx = true;
  					break;
  				case BuiltInBaseInstance:
  					// If a non-zero base instance is used, we need to adjust for it when calculating the view index.
  					builtin_base_instance_id = var.self;
  					mark_implicit_builtin(StorageClassInput, BuiltInBaseInstance, var.self);
  					has_base_instance = true;
  					break;
  				case BuiltInViewIndex:
  					builtin_view_idx_id = var.self;
  					mark_implicit_builtin(StorageClassInput, BuiltInViewIndex, var.self);
  					has_view_idx = true;
  					break;
  				default:
  					break;
  				}
  			}
  
  			if (need_local_invocation_index && builtin == BuiltInLocalInvocationIndex)
  			{
  				builtin_local_invocation_index_id = var.self;
  				mark_implicit_builtin(StorageClassInput, BuiltInLocalInvocationIndex, var.self);
  				has_local_invocation_index = true;
  			}
  
  			if (need_workgroup_size && builtin == BuiltInLocalInvocationId)
  			{
  				builtin_workgroup_size_id = var.self;
  				mark_implicit_builtin(StorageClassInput, BuiltInWorkgroupSize, var.self);
  				has_workgroup_size = true;
  			}
  
  			// The base workgroup needs to have the same type and vector size
  			// as the workgroup or invocation ID, so keep track of the type that
  			// was used.
  			if (need_dispatch_base && workgroup_id_type == 0 &&
  			    (builtin == BuiltInWorkgroupId || builtin == BuiltInGlobalInvocationId))
  				workgroup_id_type = var.basetype;
  		});
  
  		// Use Metal's native frame-buffer fetch API for subpass inputs.
  		if ((!has_frag_coord || (msl_options.multiview && !has_view_idx) ||
  		     (msl_options.arrayed_subpass_input && !msl_options.multiview && !has_layer)) &&
  		    (!msl_options.use_framebuffer_fetch_subpasses) && need_subpass_input)
  		{
  			if (!has_frag_coord)
  			{
  				uint32_t offset = ir.increase_bound_by(3);
  				uint32_t type_id = offset;
  				uint32_t type_ptr_id = offset + 1;
  				uint32_t var_id = offset + 2;
  
  				// Create gl_FragCoord.
  				SPIRType vec4_type;
  				vec4_type.basetype = SPIRType::Float;
  				vec4_type.width = 32;
  				vec4_type.vecsize = 4;
  				set<SPIRType>(type_id, vec4_type);
  
  				SPIRType vec4_type_ptr;
  				vec4_type_ptr = vec4_type;
  				vec4_type_ptr.pointer = true;
  				vec4_type_ptr.pointer_depth++;
  				vec4_type_ptr.parent_type = type_id;
  				vec4_type_ptr.storage = StorageClassInput;
  				auto &ptr_type = set<SPIRType>(type_ptr_id, vec4_type_ptr);
  				ptr_type.self = type_id;
  
  				set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
  				set_decoration(var_id, DecorationBuiltIn, BuiltInFragCoord);
  				builtin_frag_coord_id = var_id;
  				mark_implicit_builtin(StorageClassInput, BuiltInFragCoord, var_id);
  			}
  
  			if (!has_layer && msl_options.arrayed_subpass_input && !msl_options.multiview)
  			{
  				uint32_t offset = ir.increase_bound_by(2);
  				uint32_t type_ptr_id = offset;
  				uint32_t var_id = offset + 1;
  
  				// Create gl_Layer.
  				SPIRType uint_type_ptr;
  				uint_type_ptr = get_uint_type();
  				uint_type_ptr.pointer = true;
  				uint_type_ptr.pointer_depth++;
  				uint_type_ptr.parent_type = get_uint_type_id();
  				uint_type_ptr.storage = StorageClassInput;
  				auto &ptr_type = set<SPIRType>(type_ptr_id, uint_type_ptr);
  				ptr_type.self = get_uint_type_id();
  
  				set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
  				set_decoration(var_id, DecorationBuiltIn, BuiltInLayer);
  				builtin_layer_id = var_id;
  				mark_implicit_builtin(StorageClassInput, BuiltInLayer, var_id);
  			}
  
  			if (!has_view_idx && msl_options.multiview)
  			{
  				uint32_t offset = ir.increase_bound_by(2);
  				uint32_t type_ptr_id = offset;
  				uint32_t var_id = offset + 1;
  
  				// Create gl_ViewIndex.
  				SPIRType uint_type_ptr;
  				uint_type_ptr = get_uint_type();
  				uint_type_ptr.pointer = true;
  				uint_type_ptr.pointer_depth++;
  				uint_type_ptr.parent_type = get_uint_type_id();
  				uint_type_ptr.storage = StorageClassInput;
  				auto &ptr_type = set<SPIRType>(type_ptr_id, uint_type_ptr);
  				ptr_type.self = get_uint_type_id();
  
  				set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
  				set_decoration(var_id, DecorationBuiltIn, BuiltInViewIndex);
  				builtin_view_idx_id = var_id;
  				mark_implicit_builtin(StorageClassInput, BuiltInViewIndex, var_id);
  			}
  		}
  
  		if (!has_sample_id && (need_sample_pos || needs_sample_id))
  		{
  			uint32_t offset = ir.increase_bound_by(2);
  			uint32_t type_ptr_id = offset;
  			uint32_t var_id = offset + 1;
  
  			// Create gl_SampleID.
  			SPIRType uint_type_ptr;
  			uint_type_ptr = get_uint_type();
  			uint_type_ptr.pointer = true;
  			uint_type_ptr.pointer_depth++;
  			uint_type_ptr.parent_type = get_uint_type_id();
  			uint_type_ptr.storage = StorageClassInput;
  			auto &ptr_type = set<SPIRType>(type_ptr_id, uint_type_ptr);
  			ptr_type.self = get_uint_type_id();
  
  			set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
  			set_decoration(var_id, DecorationBuiltIn, BuiltInSampleId);
  			builtin_sample_id_id = var_id;
  			mark_implicit_builtin(StorageClassInput, BuiltInSampleId, var_id);
  		}
  
  		if ((need_vertex_params && (!has_vertex_idx || !has_base_vertex || !has_instance_idx || !has_base_instance)) ||
  		    (need_multiview && (!has_instance_idx || !has_base_instance || !has_view_idx)))
  		{
  			uint32_t type_ptr_id = ir.increase_bound_by(1);
  
  			SPIRType uint_type_ptr;
  			uint_type_ptr = get_uint_type();
  			uint_type_ptr.pointer = true;
  			uint_type_ptr.pointer_depth++;
  			uint_type_ptr.parent_type = get_uint_type_id();
  			uint_type_ptr.storage = StorageClassInput;
  			auto &ptr_type = set<SPIRType>(type_ptr_id, uint_type_ptr);
  			ptr_type.self = get_uint_type_id();
  
  			if (need_vertex_params && !has_vertex_idx)
  			{
  				uint32_t var_id = ir.increase_bound_by(1);
  
  				// Create gl_VertexIndex.
  				set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
  				set_decoration(var_id, DecorationBuiltIn, BuiltInVertexIndex);
  				builtin_vertex_idx_id = var_id;
  				mark_implicit_builtin(StorageClassInput, BuiltInVertexIndex, var_id);
  			}
  
  			if (need_vertex_params && !has_base_vertex)
  			{
  				uint32_t var_id = ir.increase_bound_by(1);
  
  				// Create gl_BaseVertex.
  				set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
  				set_decoration(var_id, DecorationBuiltIn, BuiltInBaseVertex);
  				builtin_base_vertex_id = var_id;
  				mark_implicit_builtin(StorageClassInput, BuiltInBaseVertex, var_id);
  			}
  
  			if (!has_instance_idx) // Needed by both multiview and tessellation
  			{
  				uint32_t var_id = ir.increase_bound_by(1);
  
  				// Create gl_InstanceIndex.
  				set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
  				set_decoration(var_id, DecorationBuiltIn, BuiltInInstanceIndex);
  				builtin_instance_idx_id = var_id;
  				mark_implicit_builtin(StorageClassInput, BuiltInInstanceIndex, var_id);
  			}
  
  			if (!has_base_instance) // Needed by both multiview and tessellation
  			{
  				uint32_t var_id = ir.increase_bound_by(1);
  
  				// Create gl_BaseInstance.
  				set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
  				set_decoration(var_id, DecorationBuiltIn, BuiltInBaseInstance);
  				builtin_base_instance_id = var_id;
  				mark_implicit_builtin(StorageClassInput, BuiltInBaseInstance, var_id);
  			}
  
  			if (need_multiview)
  			{
  				// Multiview shaders are not allowed to write to gl_Layer, ostensibly because
  				// it is implicitly written from gl_ViewIndex, but we have to do that explicitly.
  				// Note that we can't just abuse gl_ViewIndex for this purpose: it's an input, but
  				// gl_Layer is an output in vertex-pipeline shaders.
  				uint32_t type_ptr_out_id = ir.increase_bound_by(2);
  				SPIRType uint_type_ptr_out;
  				uint_type_ptr_out = get_uint_type();
  				uint_type_ptr_out.pointer = true;
  				uint_type_ptr_out.pointer_depth++;
  				uint_type_ptr_out.parent_type = get_uint_type_id();
  				uint_type_ptr_out.storage = StorageClassOutput;
  				auto &ptr_out_type = set<SPIRType>(type_ptr_out_id, uint_type_ptr_out);
  				ptr_out_type.self = get_uint_type_id();
  				uint32_t var_id = type_ptr_out_id + 1;
  				set<SPIRVariable>(var_id, type_ptr_out_id, StorageClassOutput);
  				set_decoration(var_id, DecorationBuiltIn, BuiltInLayer);
  				builtin_layer_id = var_id;
  				mark_implicit_builtin(StorageClassOutput, BuiltInLayer, var_id);
  			}
  
  			if (need_multiview && !has_view_idx)
  			{
  				uint32_t var_id = ir.increase_bound_by(1);
  
  				// Create gl_ViewIndex.
  				set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
  				set_decoration(var_id, DecorationBuiltIn, BuiltInViewIndex);
  				builtin_view_idx_id = var_id;
  				mark_implicit_builtin(StorageClassInput, BuiltInViewIndex, var_id);
  			}
  		}
  
  		if ((need_tesc_params && (msl_options.multi_patch_workgroup || !has_invocation_id || !has_primitive_id)) ||
  		    need_grid_params)
  		{
  			uint32_t type_ptr_id = ir.increase_bound_by(1);
  
  			SPIRType uint_type_ptr;
  			uint_type_ptr = get_uint_type();
  			uint_type_ptr.pointer = true;
  			uint_type_ptr.pointer_depth++;
  			uint_type_ptr.parent_type = get_uint_type_id();
  			uint_type_ptr.storage = StorageClassInput;
  			auto &ptr_type = set<SPIRType>(type_ptr_id, uint_type_ptr);
  			ptr_type.self = get_uint_type_id();
  
  			if (msl_options.multi_patch_workgroup || need_grid_params)
  			{
  				uint32_t var_id = ir.increase_bound_by(1);
  
  				// Create gl_GlobalInvocationID.
  				set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
  				set_decoration(var_id, DecorationBuiltIn, BuiltInGlobalInvocationId);
  				builtin_invocation_id_id = var_id;
  				mark_implicit_builtin(StorageClassInput, BuiltInGlobalInvocationId, var_id);
  			}
  			else if (need_tesc_params && !has_invocation_id)
  			{
  				uint32_t var_id = ir.increase_bound_by(1);
  
  				// Create gl_InvocationID.
  				set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
  				set_decoration(var_id, DecorationBuiltIn, BuiltInInvocationId);
  				builtin_invocation_id_id = var_id;
  				mark_implicit_builtin(StorageClassInput, BuiltInInvocationId, var_id);
  			}
  
  			if (need_tesc_params && !has_primitive_id)
  			{
  				uint32_t var_id = ir.increase_bound_by(1);
  
  				// Create gl_PrimitiveID.
  				set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
  				set_decoration(var_id, DecorationBuiltIn, BuiltInPrimitiveId);
  				builtin_primitive_id_id = var_id;
  				mark_implicit_builtin(StorageClassInput, BuiltInPrimitiveId, var_id);
  			}
  
  			if (need_grid_params)
  			{
  				uint32_t var_id = ir.increase_bound_by(1);
  
  				set<SPIRVariable>(var_id, build_extended_vector_type(get_uint_type_id(), 3), StorageClassInput);
  				set_extended_decoration(var_id, SPIRVCrossDecorationBuiltInStageInputSize);
  				get_entry_point().interface_variables.push_back(var_id);
  				set_name(var_id, "spvStageInputSize");
  				builtin_stage_input_size_id = var_id;
  			}
  		}
  
  		if (!has_subgroup_invocation_id && (need_subgroup_mask || needs_subgroup_invocation_id))
  		{
  			uint32_t offset = ir.increase_bound_by(2);
  			uint32_t type_ptr_id = offset;
  			uint32_t var_id = offset + 1;
  
  			// Create gl_SubgroupInvocationID.
  			SPIRType uint_type_ptr;
  			uint_type_ptr = get_uint_type();
  			uint_type_ptr.pointer = true;
  			uint_type_ptr.pointer_depth++;
  			uint_type_ptr.parent_type = get_uint_type_id();
  			uint_type_ptr.storage = StorageClassInput;
  			auto &ptr_type = set<SPIRType>(type_ptr_id, uint_type_ptr);
  			ptr_type.self = get_uint_type_id();
  
  			set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
  			set_decoration(var_id, DecorationBuiltIn, BuiltInSubgroupLocalInvocationId);
  			builtin_subgroup_invocation_id_id = var_id;
  			mark_implicit_builtin(StorageClassInput, BuiltInSubgroupLocalInvocationId, var_id);
  		}
  
  		if (!has_subgroup_size && (need_subgroup_ge_mask || needs_subgroup_size))
  		{
  			uint32_t offset = ir.increase_bound_by(2);
  			uint32_t type_ptr_id = offset;
  			uint32_t var_id = offset + 1;
  
  			// Create gl_SubgroupSize.
  			SPIRType uint_type_ptr;
  			uint_type_ptr = get_uint_type();
  			uint_type_ptr.pointer = true;
  			uint_type_ptr.pointer_depth++;
  			uint_type_ptr.parent_type = get_uint_type_id();
  			uint_type_ptr.storage = StorageClassInput;
  			auto &ptr_type = set<SPIRType>(type_ptr_id, uint_type_ptr);
  			ptr_type.self = get_uint_type_id();
  
  			set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
  			set_decoration(var_id, DecorationBuiltIn, BuiltInSubgroupSize);
  			builtin_subgroup_size_id = var_id;
  			mark_implicit_builtin(StorageClassInput, BuiltInSubgroupSize, var_id);
  		}
  
  		if (need_dispatch_base || need_vertex_base_params)
  		{
  			if (workgroup_id_type == 0)
  				workgroup_id_type = build_extended_vector_type(get_uint_type_id(), 3);
  			uint32_t var_id;
  			if (msl_options.supports_msl_version(1, 2))
  			{
  				// If we have MSL 1.2, we can (ab)use the [[grid_origin]] builtin
  				// to convey this information and save a buffer slot.
  				uint32_t offset = ir.increase_bound_by(1);
  				var_id = offset;
  
  				set<SPIRVariable>(var_id, workgroup_id_type, StorageClassInput);
  				set_extended_decoration(var_id, SPIRVCrossDecorationBuiltInDispatchBase);
  				get_entry_point().interface_variables.push_back(var_id);
  			}
  			else
  			{
  				// Otherwise, we need to fall back to a good ol' fashioned buffer.
  				uint32_t offset = ir.increase_bound_by(2);
  				var_id = offset;
  				uint32_t type_id = offset + 1;
  
  				SPIRType var_type = get<SPIRType>(workgroup_id_type);
  				var_type.storage = StorageClassUniform;
  				set<SPIRType>(type_id, var_type);
  
  				set<SPIRVariable>(var_id, type_id, StorageClassUniform);
  				// This should never match anything.
  				set_decoration(var_id, DecorationDescriptorSet, ~(5u));
  				set_decoration(var_id, DecorationBinding, msl_options.indirect_params_buffer_index);
  				set_extended_decoration(var_id, SPIRVCrossDecorationResourceIndexPrimary,
  				                        msl_options.indirect_params_buffer_index);
  			}
  			set_name(var_id, "spvDispatchBase");
  			builtin_dispatch_base_id = var_id;
  		}
  
  		if (has_additional_fixed_sample_mask() && !does_shader_write_sample_mask)
  		{
  			uint32_t offset = ir.increase_bound_by(2);
  			uint32_t var_id = offset + 1;
  
  			// Create gl_SampleMask.
  			SPIRType uint_type_ptr_out;
  			uint_type_ptr_out = get_uint_type();
  			uint_type_ptr_out.pointer = true;
  			uint_type_ptr_out.pointer_depth++;
  			uint_type_ptr_out.parent_type = get_uint_type_id();
  			uint_type_ptr_out.storage = StorageClassOutput;
  
  			auto &ptr_out_type = set<SPIRType>(offset, uint_type_ptr_out);
  			ptr_out_type.self = get_uint_type_id();
  			set<SPIRVariable>(var_id, offset, StorageClassOutput);
  			set_decoration(var_id, DecorationBuiltIn, BuiltInSampleMask);
  			builtin_sample_mask_id = var_id;
  			mark_implicit_builtin(StorageClassOutput, BuiltInSampleMask, var_id);
  		}
  
  		if (need_local_invocation_index && !has_local_invocation_index)
  		{
  			uint32_t offset = ir.increase_bound_by(2);
  			uint32_t type_ptr_id = offset;
  			uint32_t var_id = offset + 1;
  
  			// Create gl_LocalInvocationIndex.
  			SPIRType uint_type_ptr;
  			uint_type_ptr = get_uint_type();
  			uint_type_ptr.pointer = true;
  			uint_type_ptr.pointer_depth++;
  			uint_type_ptr.parent_type = get_uint_type_id();
  			uint_type_ptr.storage = StorageClassInput;
  
  			auto &ptr_type = set<SPIRType>(type_ptr_id, uint_type_ptr);
  			ptr_type.self = get_uint_type_id();
  			set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
  			set_decoration(var_id, DecorationBuiltIn, BuiltInLocalInvocationIndex);
  			builtin_local_invocation_index_id = var_id;
  			mark_implicit_builtin(StorageClassInput, BuiltInLocalInvocationIndex, var_id);
  		}
  
  		if (need_workgroup_size && !has_workgroup_size)
  		{
  			uint32_t offset = ir.increase_bound_by(2);
  			uint32_t type_ptr_id = offset;
  			uint32_t var_id = offset + 1;
  
  			// Create gl_WorkgroupSize.
  			uint32_t type_id = build_extended_vector_type(get_uint_type_id(), 3);
  			SPIRType uint_type_ptr = get<SPIRType>(type_id);
  			uint_type_ptr.pointer = true;
  			uint_type_ptr.pointer_depth++;
  			uint_type_ptr.parent_type = type_id;
  			uint_type_ptr.storage = StorageClassInput;
  
  			auto &ptr_type = set<SPIRType>(type_ptr_id, uint_type_ptr);
  			ptr_type.self = type_id;
  			set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
  			set_decoration(var_id, DecorationBuiltIn, BuiltInWorkgroupSize);
  			builtin_workgroup_size_id = var_id;
  			mark_implicit_builtin(StorageClassInput, BuiltInWorkgroupSize, var_id);
  		}
  	}
  
  	if (needs_swizzle_buffer_def)
  	{
  		uint32_t var_id = build_constant_uint_array_pointer();
  		set_name(var_id, "spvSwizzleConstants");
  		// This should never match anything.
  		set_decoration(var_id, DecorationDescriptorSet, kSwizzleBufferBinding);
  		set_decoration(var_id, DecorationBinding, msl_options.swizzle_buffer_index);
  		set_extended_decoration(var_id, SPIRVCrossDecorationResourceIndexPrimary, msl_options.swizzle_buffer_index);
  		swizzle_buffer_id = var_id;
  	}
  
  	if (!buffers_requiring_array_length.empty())
  	{
  		uint32_t var_id = build_constant_uint_array_pointer();
  		set_name(var_id, "spvBufferSizeConstants");
  		// This should never match anything.
  		set_decoration(var_id, DecorationDescriptorSet, kBufferSizeBufferBinding);
  		set_decoration(var_id, DecorationBinding, msl_options.buffer_size_buffer_index);
  		set_extended_decoration(var_id, SPIRVCrossDecorationResourceIndexPrimary, msl_options.buffer_size_buffer_index);
  		buffer_size_buffer_id = var_id;
  	}
  
  	if (needs_view_mask_buffer())
  	{
  		uint32_t var_id = build_constant_uint_array_pointer();
  		set_name(var_id, "spvViewMask");
  		// This should never match anything.
  		set_decoration(var_id, DecorationDescriptorSet, ~(4u));
  		set_decoration(var_id, DecorationBinding, msl_options.view_mask_buffer_index);
  		set_extended_decoration(var_id, SPIRVCrossDecorationResourceIndexPrimary, msl_options.view_mask_buffer_index);
  		view_mask_buffer_id = var_id;
  	}
  
  	if (!buffers_requiring_dynamic_offset.empty())
  	{
  		uint32_t var_id = build_constant_uint_array_pointer();
  		set_name(var_id, "spvDynamicOffsets");
  		// This should never match anything.
  		set_decoration(var_id, DecorationDescriptorSet, ~(5u));
  		set_decoration(var_id, DecorationBinding, msl_options.dynamic_offsets_buffer_index);
  		set_extended_decoration(var_id, SPIRVCrossDecorationResourceIndexPrimary,
  		                        msl_options.dynamic_offsets_buffer_index);
  		dynamic_offsets_buffer_id = var_id;
  	}
  
  	// If we're returning a struct from a vertex-like entry point, we must return a position attribute.
  	bool need_position =
  			(get_execution_model() == ExecutionModelVertex ||
  			 get_execution_model() == ExecutionModelTessellationEvaluation) &&
  			!capture_output_to_buffer && !get_is_rasterization_disabled() &&
  			!active_output_builtins.get(BuiltInPosition);
  
  	if (need_position)
  	{
  		// If we can get away with returning void from entry point, we don't need to care.
  		// If there is at least one other stage output, we need to return [[position]],
  		// so we need to create one if it doesn't appear in the SPIR-V. Before adding the
  		// implicit variable, check if it actually exists already, but just has not been used
  		// or initialized, and if so, mark it as active, and do not create the implicit variable.
  		bool has_output = false;
  		ir.for_each_typed_id<SPIRVariable>([&](uint32_t, SPIRVariable &var) {
  			if (var.storage == StorageClassOutput && interface_variable_exists_in_entry_point(var.self))
  			{
  				has_output = true;
  
  				// Check if the var is the Position builtin
  				if (has_decoration(var.self, DecorationBuiltIn) && get_decoration(var.self, DecorationBuiltIn) == BuiltInPosition)
  					active_output_builtins.set(BuiltInPosition);
  
  				// If the var is a struct, check if any members is the Position builtin
  				auto &var_type = get_variable_element_type(var);
  				if (var_type.basetype == SPIRType::Struct)
  				{
  					auto mbr_cnt = var_type.member_types.size();
  					for (uint32_t mbr_idx = 0; mbr_idx < mbr_cnt; mbr_idx++)
  					{
  						auto builtin = BuiltInMax;
  						bool is_builtin = is_member_builtin(var_type, mbr_idx, &builtin);
  						if (is_builtin && builtin == BuiltInPosition)
  							active_output_builtins.set(BuiltInPosition);
  					}
  				}
  			}
  		});
  		need_position = has_output && !active_output_builtins.get(BuiltInPosition);
  	}
  
  	if (need_position)
  	{
  		uint32_t offset = ir.increase_bound_by(3);
  		uint32_t type_id = offset;
  		uint32_t type_ptr_id = offset + 1;
  		uint32_t var_id = offset + 2;
  
  		// Create gl_Position.
  		SPIRType vec4_type;
  		vec4_type.basetype = SPIRType::Float;
  		vec4_type.width = 32;
  		vec4_type.vecsize = 4;
  		set<SPIRType>(type_id, vec4_type);
  
  		SPIRType vec4_type_ptr;
  		vec4_type_ptr = vec4_type;
  		vec4_type_ptr.pointer = true;
  		vec4_type_ptr.pointer_depth++;
  		vec4_type_ptr.parent_type = type_id;
  		vec4_type_ptr.storage = StorageClassOutput;
  		auto &ptr_type = set<SPIRType>(type_ptr_id, vec4_type_ptr);
  		ptr_type.self = type_id;
  
  		set<SPIRVariable>(var_id, type_ptr_id, StorageClassOutput);
  		set_decoration(var_id, DecorationBuiltIn, BuiltInPosition);
  		mark_implicit_builtin(StorageClassOutput, BuiltInPosition, var_id);
  	}
  }
  
  // Checks if the specified builtin variable (e.g. gl_InstanceIndex) is marked as active.
  // If not, it marks it as active and forces a recompilation.
  // This might be used when the optimization of inactive builtins was too optimistic (e.g. when "spvOut" is emitted).
  void CompilerMSL::ensure_builtin(spv::StorageClass storage, spv::BuiltIn builtin)
  {
  	Bitset *active_builtins = nullptr;
  	switch (storage)
  	{
  	case StorageClassInput:
  		active_builtins = &active_input_builtins;
  		break;
  
  	case StorageClassOutput:
  		active_builtins = &active_output_builtins;
  		break;
  
  	default:
  		break;
  	}
  
  	// At this point, the specified builtin variable must have already been declared in the entry point.
  	// If not, mark as active and force recompile.
  	if (active_builtins != nullptr && !active_builtins->get(builtin))
  	{
  		active_builtins->set(builtin);
  		force_recompile();
  	}
  }
  
  void CompilerMSL::mark_implicit_builtin(StorageClass storage, BuiltIn builtin, uint32_t id)
  {
  	Bitset *active_builtins = nullptr;
  	switch (storage)
  	{
  	case StorageClassInput:
  		active_builtins = &active_input_builtins;
  		break;
  
  	case StorageClassOutput:
  		active_builtins = &active_output_builtins;
  		break;
  
  	default:
  		break;
  	}
  
  	assert(active_builtins != nullptr);
  	active_builtins->set(builtin);
  
  	auto &var = get_entry_point().interface_variables;
  	if (find(begin(var), end(var), VariableID(id)) == end(var))
  		var.push_back(id);
  }
  
  uint32_t CompilerMSL::build_constant_uint_array_pointer()
  {
  	uint32_t offset = ir.increase_bound_by(3);
  	uint32_t type_ptr_id = offset;
  	uint32_t type_ptr_ptr_id = offset + 1;
  	uint32_t var_id = offset + 2;
  
  	// Create a buffer to hold extra data, including the swizzle constants.
  	SPIRType uint_type_pointer = get_uint_type();
  	uint_type_pointer.pointer = true;
  	uint_type_pointer.pointer_depth++;
  	uint_type_pointer.parent_type = get_uint_type_id();
  	uint_type_pointer.storage = StorageClassUniform;
  	set<SPIRType>(type_ptr_id, uint_type_pointer);
  	set_decoration(type_ptr_id, DecorationArrayStride, 4);
  
  	SPIRType uint_type_pointer2 = uint_type_pointer;
  	uint_type_pointer2.pointer_depth++;
  	uint_type_pointer2.parent_type = type_ptr_id;
  	set<SPIRType>(type_ptr_ptr_id, uint_type_pointer2);
  
  	set<SPIRVariable>(var_id, type_ptr_ptr_id, StorageClassUniformConstant);
  	return var_id;
  }
  
  static string create_sampler_address(const char *prefix, MSLSamplerAddress addr)
  {
  	switch (addr)
  	{
  	case MSL_SAMPLER_ADDRESS_CLAMP_TO_EDGE:
  		return join(prefix, "address::clamp_to_edge");
  	case MSL_SAMPLER_ADDRESS_CLAMP_TO_ZERO:
  		return join(prefix, "address::clamp_to_zero");
  	case MSL_SAMPLER_ADDRESS_CLAMP_TO_BORDER:
  		return join(prefix, "address::clamp_to_border");
  	case MSL_SAMPLER_ADDRESS_REPEAT:
  		return join(prefix, "address::repeat");
  	case MSL_SAMPLER_ADDRESS_MIRRORED_REPEAT:
  		return join(prefix, "address::mirrored_repeat");
  	default:
  		SPIRV_CROSS_THROW("Invalid sampler addressing mode.");
  	}
  }
  
  SPIRType &CompilerMSL::get_stage_in_struct_type()
  {
  	auto &si_var = get<SPIRVariable>(stage_in_var_id);
  	return get_variable_data_type(si_var);
  }
  
  SPIRType &CompilerMSL::get_stage_out_struct_type()
  {
  	auto &so_var = get<SPIRVariable>(stage_out_var_id);
  	return get_variable_data_type(so_var);
  }
  
  SPIRType &CompilerMSL::get_patch_stage_in_struct_type()
  {
  	auto &si_var = get<SPIRVariable>(patch_stage_in_var_id);
  	return get_variable_data_type(si_var);
  }
  
  SPIRType &CompilerMSL::get_patch_stage_out_struct_type()
  {
  	auto &so_var = get<SPIRVariable>(patch_stage_out_var_id);
  	return get_variable_data_type(so_var);
  }
  
  std::string CompilerMSL::get_tess_factor_struct_name()
  {
  	if (get_entry_point().flags.get(ExecutionModeTriangles))
  		return "MTLTriangleTessellationFactorsHalf";
  	return "MTLQuadTessellationFactorsHalf";
  }
  
  SPIRType &CompilerMSL::get_uint_type()
  {
  	return get<SPIRType>(get_uint_type_id());
  }
  
  uint32_t CompilerMSL::get_uint_type_id()
  {
  	if (uint_type_id != 0)
  		return uint_type_id;
  
  	uint_type_id = ir.increase_bound_by(1);
  
  	SPIRType type;
  	type.basetype = SPIRType::UInt;
  	type.width = 32;
  	set<SPIRType>(uint_type_id, type);
  	return uint_type_id;
  }
  
  void CompilerMSL::emit_entry_point_declarations()
  {
  	// FIXME: Get test coverage here ...
  	// Constant arrays of non-primitive types (i.e. matrices) won't link properly into Metal libraries
  	declare_complex_constant_arrays();
  
  	// Emit constexpr samplers here.
  	for (auto &samp : constexpr_samplers_by_id)
  	{
  		auto &var = get<SPIRVariable>(samp.first);
  		auto &type = get<SPIRType>(var.basetype);
  		if (type.basetype == SPIRType::Sampler)
  			add_resource_name(samp.first);
  
  		SmallVector<string> args;
  		auto &s = samp.second;
  
  		if (s.coord != MSL_SAMPLER_COORD_NORMALIZED)
  			args.push_back("coord::pixel");
  
  		if (s.min_filter == s.mag_filter)
  		{
  			if (s.min_filter != MSL_SAMPLER_FILTER_NEAREST)
  				args.push_back("filter::linear");
  		}
  		else
  		{
  			if (s.min_filter != MSL_SAMPLER_FILTER_NEAREST)
  				args.push_back("min_filter::linear");
  			if (s.mag_filter != MSL_SAMPLER_FILTER_NEAREST)
  				args.push_back("mag_filter::linear");
  		}
  
  		switch (s.mip_filter)
  		{
  		case MSL_SAMPLER_MIP_FILTER_NONE:
  			// Default
  			break;
  		case MSL_SAMPLER_MIP_FILTER_NEAREST:
  			args.push_back("mip_filter::nearest");
  			break;
  		case MSL_SAMPLER_MIP_FILTER_LINEAR:
  			args.push_back("mip_filter::linear");
  			break;
  		default:
  			SPIRV_CROSS_THROW("Invalid mip filter.");
  		}
  
  		if (s.s_address == s.t_address && s.s_address == s.r_address)
  		{
  			if (s.s_address != MSL_SAMPLER_ADDRESS_CLAMP_TO_EDGE)
  				args.push_back(create_sampler_address("", s.s_address));
  		}
  		else
  		{
  			if (s.s_address != MSL_SAMPLER_ADDRESS_CLAMP_TO_EDGE)
  				args.push_back(create_sampler_address("s_", s.s_address));
  			if (s.t_address != MSL_SAMPLER_ADDRESS_CLAMP_TO_EDGE)
  				args.push_back(create_sampler_address("t_", s.t_address));
  			if (s.r_address != MSL_SAMPLER_ADDRESS_CLAMP_TO_EDGE)
  				args.push_back(create_sampler_address("r_", s.r_address));
  		}
  
  		if (s.compare_enable)
  		{
  			switch (s.compare_func)
  			{
  			case MSL_SAMPLER_COMPARE_FUNC_ALWAYS:
  				args.push_back("compare_func::always");
  				break;
  			case MSL_SAMPLER_COMPARE_FUNC_NEVER:
  				args.push_back("compare_func::never");
  				break;
  			case MSL_SAMPLER_COMPARE_FUNC_EQUAL:
  				args.push_back("compare_func::equal");
  				break;
  			case MSL_SAMPLER_COMPARE_FUNC_NOT_EQUAL:
  				args.push_back("compare_func::not_equal");
  				break;
  			case MSL_SAMPLER_COMPARE_FUNC_LESS:
  				args.push_back("compare_func::less");
  				break;
  			case MSL_SAMPLER_COMPARE_FUNC_LESS_EQUAL:
  				args.push_back("compare_func::less_equal");
  				break;
  			case MSL_SAMPLER_COMPARE_FUNC_GREATER:
  				args.push_back("compare_func::greater");
  				break;
  			case MSL_SAMPLER_COMPARE_FUNC_GREATER_EQUAL:
  				args.push_back("compare_func::greater_equal");
  				break;
  			default:
  				SPIRV_CROSS_THROW("Invalid sampler compare function.");
  			}
  		}
  
  		if (s.s_address == MSL_SAMPLER_ADDRESS_CLAMP_TO_BORDER || s.t_address == MSL_SAMPLER_ADDRESS_CLAMP_TO_BORDER ||
  		    s.r_address == MSL_SAMPLER_ADDRESS_CLAMP_TO_BORDER)
  		{
  			switch (s.border_color)
  			{
  			case MSL_SAMPLER_BORDER_COLOR_OPAQUE_BLACK:
  				args.push_back("border_color::opaque_black");
  				break;
  			case MSL_SAMPLER_BORDER_COLOR_OPAQUE_WHITE:
  				args.push_back("border_color::opaque_white");
  				break;
  			case MSL_SAMPLER_BORDER_COLOR_TRANSPARENT_BLACK:
  				args.push_back("border_color::transparent_black");
  				break;
  			default:
  				SPIRV_CROSS_THROW("Invalid sampler border color.");
  			}
  		}
  
  		if (s.anisotropy_enable)
  			args.push_back(join("max_anisotropy(", s.max_anisotropy, ")"));
  		if (s.lod_clamp_enable)
  		{
  			args.push_back(join("lod_clamp(", convert_to_string(s.lod_clamp_min, current_locale_radix_character), ", ",
  			                    convert_to_string(s.lod_clamp_max, current_locale_radix_character), ")"));
  		}
  
  		// If we would emit no arguments, then omit the parentheses entirely. Otherwise,
  		// we'll wind up with a "most vexing parse" situation.
  		if (args.empty())
  			statement("constexpr sampler ",
  			          type.basetype == SPIRType::SampledImage ? to_sampler_expression(samp.first) : to_name(samp.first),
  			          ";");
  		else
  			statement("constexpr sampler ",
  			          type.basetype == SPIRType::SampledImage ? to_sampler_expression(samp.first) : to_name(samp.first),
  			          "(", merge(args), ");");
  	}
  
  	// Emit dynamic buffers here.
  	for (auto &dynamic_buffer : buffers_requiring_dynamic_offset)
  	{
  		if (!dynamic_buffer.second.second)
  		{
  			// Could happen if no buffer was used at requested binding point.
  			continue;
  		}
  
  		const auto &var = get<SPIRVariable>(dynamic_buffer.second.second);
  		uint32_t var_id = var.self;
  		const auto &type = get_variable_data_type(var);
  		string name = to_name(var.self);
  		uint32_t desc_set = get_decoration(var.self, DecorationDescriptorSet);
  		uint32_t arg_id = argument_buffer_ids[desc_set];
  		uint32_t base_index = dynamic_buffer.second.first;
  
  		if (!type.array.empty())
  		{
  			// This is complicated, because we need to support arrays of arrays.
  			// And it's even worse if the outermost dimension is a runtime array, because now
  			// all this complicated goop has to go into the shader itself. (FIXME)
  			if (!type.array[type.array.size() - 1])
  				SPIRV_CROSS_THROW("Runtime arrays with dynamic offsets are not supported yet.");
  			else
  			{
  				is_using_builtin_array = true;
  				statement(get_argument_address_space(var), " ", type_to_glsl(type), "* ", to_restrict(var_id), name,
  				          type_to_array_glsl(type), " =");
  
  				uint32_t dim = uint32_t(type.array.size());
  				uint32_t j = 0;
  				for (SmallVector<uint32_t> indices(type.array.size());
  				     indices[type.array.size() - 1] < to_array_size_literal(type); j++)
  				{
  					while (dim > 0)
  					{
  						begin_scope();
  						--dim;
  					}
  
  					string arrays;
  					for (uint32_t i = uint32_t(type.array.size()); i; --i)
  						arrays += join("[", indices[i - 1], "]");
  					statement("(", get_argument_address_space(var), " ", type_to_glsl(type), "* ",
  					          to_restrict(var_id, false), ")((", get_argument_address_space(var), " char* ",
  					          to_restrict(var_id, false), ")", to_name(arg_id), ".", ensure_valid_name(name, "m"),
  					          arrays, " + ", to_name(dynamic_offsets_buffer_id), "[", base_index + j, "]),");
  
  					while (++indices[dim] >= to_array_size_literal(type, dim) && dim < type.array.size() - 1)
  					{
  						end_scope(",");
  						indices[dim++] = 0;
  					}
  				}
  				end_scope_decl();
  				statement_no_indent("");
  				is_using_builtin_array = false;
  			}
  		}
  		else
  		{
  			statement(get_argument_address_space(var), " auto& ", to_restrict(var_id), name, " = *(",
  			          get_argument_address_space(var), " ", type_to_glsl(type), "* ", to_restrict(var_id, false), ")((",
  			          get_argument_address_space(var), " char* ", to_restrict(var_id, false), ")", to_name(arg_id), ".",
  			          ensure_valid_name(name, "m"), " + ", to_name(dynamic_offsets_buffer_id), "[", base_index, "]);");
  		}
  	}
  
  	// Emit buffer arrays here.
  	for (uint32_t array_id : buffer_arrays)
  	{
  		const auto &var = get<SPIRVariable>(array_id);
  		const auto &type = get_variable_data_type(var);
  		const auto &buffer_type = get_variable_element_type(var);
  		string name = to_name(array_id);
  		statement(get_argument_address_space(var), " ", type_to_glsl(buffer_type), "* ", to_restrict(array_id), name,
  		          "[] =");
  		begin_scope();
  		for (uint32_t i = 0; i < to_array_size_literal(type); ++i)
  			statement(name, "_", i, ",");
  		end_scope_decl();
  		statement_no_indent("");
  	}
  	// For some reason, without this, we end up emitting the arrays twice.
  	buffer_arrays.clear();
  
  	// Emit disabled fragment outputs.
  	std::sort(disabled_frag_outputs.begin(), disabled_frag_outputs.end());
  	for (uint32_t var_id : disabled_frag_outputs)
  	{
  		auto &var = get<SPIRVariable>(var_id);
  		add_local_variable_name(var_id);
  		statement(variable_decl(var), ";");
  		var.deferred_declaration = false;
  	}
  }
  
  string CompilerMSL::compile()
  {
  	replace_illegal_entry_point_names();
  	ir.fixup_reserved_names();
  
  	// Do not deal with GLES-isms like precision, older extensions and such.
  	options.vulkan_semantics = true;
  	options.es = false;
  	options.version = 450;
  	backend.null_pointer_literal = "nullptr";
  	backend.float_literal_suffix = false;
  	backend.uint32_t_literal_suffix = true;
  	backend.int16_t_literal_suffix = "";
  	backend.uint16_t_literal_suffix = "";
  	backend.basic_int_type = "int";
  	backend.basic_uint_type = "uint";
  	backend.basic_int8_type = "char";
  	backend.basic_uint8_type = "uchar";
  	backend.basic_int16_type = "short";
  	backend.basic_uint16_type = "ushort";
  	backend.discard_literal = "discard_fragment()";
  	backend.demote_literal = "discard_fragment()";
  	backend.boolean_mix_function = "select";
  	backend.swizzle_is_function = false;
  	backend.shared_is_implied = false;
  	backend.use_initializer_list = true;
  	backend.use_typed_initializer_list = true;
  	backend.native_row_major_matrix = false;
  	backend.unsized_array_supported = false;
  	backend.can_declare_arrays_inline = false;
  	backend.allow_truncated_access_chain = true;
  	backend.comparison_image_samples_scalar = true;
  	backend.native_pointers = true;
  	backend.nonuniform_qualifier = "";
  	backend.support_small_type_sampling_result = true;
  	backend.supports_empty_struct = true;
  
  	// Allow Metal to use the array<T> template unless we force it off.
  	backend.can_return_array = !msl_options.force_native_arrays;
  	backend.array_is_value_type = !msl_options.force_native_arrays;
  	// Arrays which are part of buffer objects are never considered to be native arrays.
  	backend.buffer_offset_array_is_value_type = false;
  	backend.support_pointer_to_pointer = true;
  
  	capture_output_to_buffer = msl_options.capture_output_to_buffer;
  	is_rasterization_disabled = msl_options.disable_rasterization || capture_output_to_buffer;
  
  	// Initialize array here rather than constructor, MSVC 2013 workaround.
  	for (auto &id : next_metal_resource_ids)
  		id = 0;
  
  	fixup_type_alias();
  	replace_illegal_names();
  	sync_entry_point_aliases_and_names();
  
  	build_function_control_flow_graphs_and_analyze();
  	update_active_builtins();
  	analyze_image_and_sampler_usage();
  	analyze_sampled_image_usage();
  	analyze_interlocked_resource_usage();
  	preprocess_op_codes();
  	build_implicit_builtins();
  
  	fixup_image_load_store_access();
  
  	set_enabled_interface_variables(get_active_interface_variables());
  	if (msl_options.force_active_argument_buffer_resources)
  		activate_argument_buffer_resources();
  
  	if (swizzle_buffer_id)
  		active_interface_variables.insert(swizzle_buffer_id);
  	if (buffer_size_buffer_id)
  		active_interface_variables.insert(buffer_size_buffer_id);
  	if (view_mask_buffer_id)
  		active_interface_variables.insert(view_mask_buffer_id);
  	if (dynamic_offsets_buffer_id)
  		active_interface_variables.insert(dynamic_offsets_buffer_id);
  	if (builtin_layer_id)
  		active_interface_variables.insert(builtin_layer_id);
  	if (builtin_dispatch_base_id && !msl_options.supports_msl_version(1, 2))
  		active_interface_variables.insert(builtin_dispatch_base_id);
  	if (builtin_sample_mask_id)
  		active_interface_variables.insert(builtin_sample_mask_id);
  
  	// Create structs to hold input, output and uniform variables.
  	// Do output first to ensure out. is declared at top of entry function.
  	qual_pos_var_name = "";
  	stage_out_var_id = add_interface_block(StorageClassOutput);
  	patch_stage_out_var_id = add_interface_block(StorageClassOutput, true);
  	stage_in_var_id = add_interface_block(StorageClassInput);
  	if (get_execution_model() == ExecutionModelTessellationEvaluation)
  		patch_stage_in_var_id = add_interface_block(StorageClassInput, true);
  
  	if (get_execution_model() == ExecutionModelTessellationControl)
  		stage_out_ptr_var_id = add_interface_block_pointer(stage_out_var_id, StorageClassOutput);
  	if (is_tessellation_shader())
  		stage_in_ptr_var_id = add_interface_block_pointer(stage_in_var_id, StorageClassInput);
  
  	// Metal vertex functions that define no output must disable rasterization and return void.
  	if (!stage_out_var_id)
  		is_rasterization_disabled = true;
  
  	// Convert the use of global variables to recursively-passed function parameters
  	localize_global_variables();
  	extract_global_variables_from_functions();
  
  	// Mark any non-stage-in structs to be tightly packed.
  	mark_packable_structs();
  	reorder_type_alias();
  
  	// Add fixup hooks required by shader inputs and outputs. This needs to happen before
  	// the loop, so the hooks aren't added multiple times.
  	fix_up_shader_inputs_outputs();
  
  	// If we are using argument buffers, we create argument buffer structures for them here.
  	// These buffers will be used in the entry point, not the individual resources.
  	if (msl_options.argument_buffers)
  	{
  		if (!msl_options.supports_msl_version(2, 0))
  			SPIRV_CROSS_THROW("Argument buffers can only be used with MSL 2.0 and up.");
  		analyze_argument_buffers();
  	}
  
  	uint32_t pass_count = 0;
  	do
  	{
  		if (pass_count >= 3)
  			SPIRV_CROSS_THROW("Over 3 compilation loops detected. Must be a bug!");
  
  		reset();
  
  		// Start bindings at zero.
  		next_metal_resource_index_buffer = 0;
  		next_metal_resource_index_texture = 0;
  		next_metal_resource_index_sampler = 0;
  		for (auto &id : next_metal_resource_ids)
  			id = 0;
  
  		// Move constructor for this type is broken on GCC 4.9 ...
  		buffer.reset();
  
  		emit_header();
  		emit_custom_templates();
  		emit_specialization_constants_and_structs();
  		emit_resources();
  		emit_custom_functions();
  		emit_function(get<SPIRFunction>(ir.default_entry_point), Bitset());
  
  		pass_count++;
  	} while (is_forcing_recompilation());
  
  	return buffer.str();
  }
  
  // Register the need to output any custom functions.
  void CompilerMSL::preprocess_op_codes()
  {
  	OpCodePreprocessor preproc(*this);
  	traverse_all_reachable_opcodes(get<SPIRFunction>(ir.default_entry_point), preproc);
  
  	suppress_missing_prototypes = preproc.suppress_missing_prototypes;
  
  	if (preproc.uses_atomics)
  	{
  		add_header_line("#include <metal_atomic>");
  		add_pragma_line("#pragma clang diagnostic ignored \"-Wunused-variable\"");
  	}
  
  	// Before MSL 2.1 (2.2 for textures), Metal vertex functions that write to
  	// resources must disable rasterization and return void.
  	if (preproc.uses_resource_write)
  		is_rasterization_disabled = true;
  
  	// Tessellation control shaders are run as compute functions in Metal, and so
  	// must capture their output to a buffer.
  	if (get_execution_model() == ExecutionModelTessellationControl ||
  	    (get_execution_model() == ExecutionModelVertex && msl_options.vertex_for_tessellation))
  	{
  		is_rasterization_disabled = true;
  		capture_output_to_buffer = true;
  	}
  
  	if (preproc.needs_subgroup_invocation_id)
  		needs_subgroup_invocation_id = true;
  	if (preproc.needs_subgroup_size)
  		needs_subgroup_size = true;
  	// build_implicit_builtins() hasn't run yet, and in fact, this needs to execute
  	// before then so that gl_SampleID will get added; so we also need to check if
  	// that function would add gl_FragCoord.
  	if (preproc.needs_sample_id || msl_options.force_sample_rate_shading ||
  	    (is_sample_rate() && (active_input_builtins.get(BuiltInFragCoord) ||
  	                          (need_subpass_input && !msl_options.use_framebuffer_fetch_subpasses))))
  		needs_sample_id = true;
  }
  
  // Move the Private and Workgroup global variables to the entry function.
  // Non-constant variables cannot have global scope in Metal.
  void CompilerMSL::localize_global_variables()
  {
  	auto &entry_func = get<SPIRFunction>(ir.default_entry_point);
  	auto iter = global_variables.begin();
  	while (iter != global_variables.end())
  	{
  		uint32_t v_id = *iter;
  		auto &var = get<SPIRVariable>(v_id);
  		if (var.storage == StorageClassPrivate || var.storage == StorageClassWorkgroup)
  		{
  			if (!variable_is_lut(var))
  				entry_func.add_local_variable(v_id);
  			iter = global_variables.erase(iter);
  		}
  		else
  			iter++;
  	}
  }
  
  // For any global variable accessed directly by a function,
  // extract that variable and add it as an argument to that function.
  void CompilerMSL::extract_global_variables_from_functions()
  {
  	// Uniforms
  	unordered_set<uint32_t> global_var_ids;
  	ir.for_each_typed_id<SPIRVariable>([&](uint32_t, SPIRVariable &var) {
  		if (var.storage == StorageClassInput || var.storage == StorageClassOutput ||
  		    var.storage == StorageClassUniform || var.storage == StorageClassUniformConstant ||
  		    var.storage == StorageClassPushConstant || var.storage == StorageClassStorageBuffer)
  		{
  			global_var_ids.insert(var.self);
  		}
  	});
  
  	// Local vars that are declared in the main function and accessed directly by a function
  	auto &entry_func = get<SPIRFunction>(ir.default_entry_point);
  	for (auto &var : entry_func.local_variables)
  		if (get<SPIRVariable>(var).storage != StorageClassFunction)
  			global_var_ids.insert(var);
  
  	std::set<uint32_t> added_arg_ids;
  	unordered_set<uint32_t> processed_func_ids;
  	extract_global_variables_from_function(ir.default_entry_point, added_arg_ids, global_var_ids, processed_func_ids);
  }
  
  // MSL does not support the use of global variables for shader input content.
  // For any global variable accessed directly by the specified function, extract that variable,
  // add it as an argument to that function, and the arg to the added_arg_ids collection.
  void CompilerMSL::extract_global_variables_from_function(uint32_t func_id, std::set<uint32_t> &added_arg_ids,
                                                           unordered_set<uint32_t> &global_var_ids,
                                                           unordered_set<uint32_t> &processed_func_ids)
  {
  	// Avoid processing a function more than once
  	if (processed_func_ids.find(func_id) != processed_func_ids.end())
  	{
  		// Return function global variables
  		added_arg_ids = function_global_vars[func_id];
  		return;
  	}
  
  	processed_func_ids.insert(func_id);
  
  	auto &func = get<SPIRFunction>(func_id);
  
  	// Recursively establish global args added to functions on which we depend.
  	for (auto block : func.blocks)
  	{
  		auto &b = get<SPIRBlock>(block);
  		for (auto &i : b.ops)
  		{
  			auto ops = stream(i);
  			auto op = static_cast<Op>(i.op);
  
  			switch (op)
  			{
  			case OpLoad:
  			case OpInBoundsAccessChain:
  			case OpAccessChain:
  			case OpPtrAccessChain:
  			case OpArrayLength:
  			{
  				uint32_t base_id = ops[2];
  				if (global_var_ids.find(base_id) != global_var_ids.end())
  					added_arg_ids.insert(base_id);
  
  				// Use Metal's native frame-buffer fetch API for subpass inputs.
  				auto &type = get<SPIRType>(ops[0]);
  				if (type.basetype == SPIRType::Image && type.image.dim == DimSubpassData &&
  				    (!msl_options.use_framebuffer_fetch_subpasses))
  				{
  					// Implicitly reads gl_FragCoord.
  					assert(builtin_frag_coord_id != 0);
  					added_arg_ids.insert(builtin_frag_coord_id);
  					if (msl_options.multiview)
  					{
  						// Implicitly reads gl_ViewIndex.
  						assert(builtin_view_idx_id != 0);
  						added_arg_ids.insert(builtin_view_idx_id);
  					}
  					else if (msl_options.arrayed_subpass_input)
  					{
  						// Implicitly reads gl_Layer.
  						assert(builtin_layer_id != 0);
  						added_arg_ids.insert(builtin_layer_id);
  					}
  				}
  
  				break;
  			}
  
  			case OpFunctionCall:
  			{
  				// First see if any of the function call args are globals
  				for (uint32_t arg_idx = 3; arg_idx < i.length; arg_idx++)
  				{
  					uint32_t arg_id = ops[arg_idx];
  					if (global_var_ids.find(arg_id) != global_var_ids.end())
  						added_arg_ids.insert(arg_id);
  				}
  
  				// Then recurse into the function itself to extract globals used internally in the function
  				uint32_t inner_func_id = ops[2];
  				std::set<uint32_t> inner_func_args;
  				extract_global_variables_from_function(inner_func_id, inner_func_args, global_var_ids,
  				                                       processed_func_ids);
  				added_arg_ids.insert(inner_func_args.begin(), inner_func_args.end());
  				break;
  			}
  
  			case OpStore:
  			{
  				uint32_t base_id = ops[0];
  				if (global_var_ids.find(base_id) != global_var_ids.end())
  					added_arg_ids.insert(base_id);
  
  				uint32_t rvalue_id = ops[1];
  				if (global_var_ids.find(rvalue_id) != global_var_ids.end())
  					added_arg_ids.insert(rvalue_id);
  
  				break;
  			}
  
  			case OpSelect:
  			{
  				uint32_t base_id = ops[3];
  				if (global_var_ids.find(base_id) != global_var_ids.end())
  					added_arg_ids.insert(base_id);
  				base_id = ops[4];
  				if (global_var_ids.find(base_id) != global_var_ids.end())
  					added_arg_ids.insert(base_id);
  				break;
  			}
  
  			// Emulate texture2D atomic operations
  			case OpImageTexelPointer:
  			{
  				// When using the pointer, we need to know which variable it is actually loaded from.
  				uint32_t base_id = ops[2];
  				auto *var = maybe_get_backing_variable(base_id);
  				if (var && atomic_image_vars.count(var->self))
  				{
  					if (global_var_ids.find(base_id) != global_var_ids.end())
  						added_arg_ids.insert(base_id);
  				}
  				break;
  			}
  
  			case OpExtInst:
  			{
  				uint32_t extension_set = ops[2];
  				if (get<SPIRExtension>(extension_set).ext == SPIRExtension::GLSL)
  				{
  					auto op_450 = static_cast<GLSLstd450>(ops[3]);
  					switch (op_450)
  					{
  					case GLSLstd450InterpolateAtCentroid:
  					case GLSLstd450InterpolateAtSample:
  					case GLSLstd450InterpolateAtOffset:
  					{
  						// For these, we really need the stage-in block. It is theoretically possible to pass the
  						// interpolant object, but a) doing so would require us to create an entirely new variable
  						// with Interpolant type, and b) if we have a struct or array, handling all the members and
  						// elements could get unwieldy fast.
  						added_arg_ids.insert(stage_in_var_id);
  						break;
  					}
  					default:
  						break;
  					}
  				}
  				break;
  			}
  
  			case OpGroupNonUniformInverseBallot:
  			{
  				added_arg_ids.insert(builtin_subgroup_invocation_id_id);
  				break;
  			}
  
  			case OpGroupNonUniformBallotFindLSB:
  			case OpGroupNonUniformBallotFindMSB:
  			{
  				added_arg_ids.insert(builtin_subgroup_size_id);
  				break;
  			}
  
  			case OpGroupNonUniformBallotBitCount:
  			{
  				auto operation = static_cast<GroupOperation>(ops[3]);
  				switch (operation)
  				{
  				case GroupOperationReduce:
  					added_arg_ids.insert(builtin_subgroup_size_id);
  					break;
  				case GroupOperationInclusiveScan:
  				case GroupOperationExclusiveScan:
  					added_arg_ids.insert(builtin_subgroup_invocation_id_id);
  					break;
  				default:
  					break;
  				}
  				break;
  			}
  
  			default:
  				break;
  			}
  
  			// TODO: Add all other operations which can affect memory.
  			// We should consider a more unified system here to reduce boiler-plate.
  			// This kind of analysis is done in several places ...
  		}
  	}
  
  	function_global_vars[func_id] = added_arg_ids;
  
  	// Add the global variables as arguments to the function
  	if (func_id != ir.default_entry_point)
  	{
  		bool control_point_added_in = false;
  		bool control_point_added_out = false;
  		bool patch_added_in = false;
  		bool patch_added_out = false;
  
  		for (uint32_t arg_id : added_arg_ids)
  		{
  			auto &var = get<SPIRVariable>(arg_id);
  			uint32_t type_id = var.basetype;
  			auto *p_type = &get<SPIRType>(type_id);
  			BuiltIn bi_type = BuiltIn(get_decoration(arg_id, DecorationBuiltIn));
  
  			bool is_patch = has_decoration(arg_id, DecorationPatch) || is_patch_block(*p_type);
  			bool is_block = has_decoration(p_type->self, DecorationBlock);
  			bool is_control_point_storage =
  					!is_patch &&
  					((is_tessellation_shader() && var.storage == StorageClassInput) ||
  					 (get_execution_model() == ExecutionModelTessellationControl && var.storage == StorageClassOutput));
  			bool is_patch_block_storage = is_patch && is_block && var.storage == StorageClassOutput;
  			bool is_builtin = is_builtin_variable(var);
  			bool variable_is_stage_io =
  					!is_builtin || bi_type == BuiltInPosition || bi_type == BuiltInPointSize ||
  					bi_type == BuiltInClipDistance || bi_type == BuiltInCullDistance ||
  					p_type->basetype == SPIRType::Struct;
  			bool is_redirected_to_global_stage_io = (is_control_point_storage || is_patch_block_storage) &&
  			                                        variable_is_stage_io;
  
  			// If output is masked it is not considered part of the global stage IO interface.
  			if (is_redirected_to_global_stage_io && var.storage == StorageClassOutput)
  				is_redirected_to_global_stage_io = !is_stage_output_variable_masked(var);
  
  			if (is_redirected_to_global_stage_io)
  			{
  				// Tessellation control shaders see inputs and per-vertex outputs as arrays.
  				// Similarly, tessellation evaluation shaders see per-vertex inputs as arrays.
  				// We collected them into a structure; we must pass the array of this
  				// structure to the function.
  				std::string name;
  				if (is_patch)
  					name = var.storage == StorageClassInput ? patch_stage_in_var_name : patch_stage_out_var_name;
  				else
  					name = var.storage == StorageClassInput ? "gl_in" : "gl_out";
  
  				if (var.storage == StorageClassOutput && has_decoration(p_type->self, DecorationBlock))
  				{
  					// If we're redirecting a block, we might still need to access the original block
  					// variable if we're masking some members.
  					for (uint32_t mbr_idx = 0; mbr_idx < uint32_t(p_type->member_types.size()); mbr_idx++)
  					{
  						if (is_stage_output_block_member_masked(var, mbr_idx, true))
  						{
  							func.add_parameter(var.basetype, var.self, true);
  							break;
  						}
  					}
  				}
  
  				// Tessellation control shaders see inputs and per-vertex outputs as arrays.
  				// Similarly, tessellation evaluation shaders see per-vertex inputs as arrays.
  				// We collected them into a structure; we must pass the array of this
  				// structure to the function.
  				if (var.storage == StorageClassInput)
  				{
  					auto &added_in = is_patch ? patch_added_in : control_point_added_in;
  					if (added_in)
  						continue;
  					arg_id = is_patch ? patch_stage_in_var_id : stage_in_ptr_var_id;
  					added_in = true;
  				}
  				else if (var.storage == StorageClassOutput)
  				{
  					auto &added_out = is_patch ? patch_added_out : control_point_added_out;
  					if (added_out)
  						continue;
  					arg_id = is_patch ? patch_stage_out_var_id : stage_out_ptr_var_id;
  					added_out = true;
  				}
  
  				type_id = get<SPIRVariable>(arg_id).basetype;
  				uint32_t next_id = ir.increase_bound_by(1);
  				func.add_parameter(type_id, next_id, true);
  				set<SPIRVariable>(next_id, type_id, StorageClassFunction, 0, arg_id);
  
  				set_name(next_id, name);
  			}
  			else if (is_builtin && has_decoration(p_type->self, DecorationBlock))
  			{
  				// Get the pointee type
  				type_id = get_pointee_type_id(type_id);
  				p_type = &get<SPIRType>(type_id);
  
  				uint32_t mbr_idx = 0;
  				for (auto &mbr_type_id : p_type->member_types)
  				{
  					BuiltIn builtin = BuiltInMax;
  					is_builtin = is_member_builtin(*p_type, mbr_idx, &builtin);
  					if (is_builtin && has_active_builtin(builtin, var.storage))
  					{
  						// Add a arg variable with the same type and decorations as the member
  						uint32_t next_ids = ir.increase_bound_by(2);
  						uint32_t ptr_type_id = next_ids + 0;
  						uint32_t var_id = next_ids + 1;
  
  						// Make sure we have an actual pointer type,
  						// so that we will get the appropriate address space when declaring these builtins.
  						auto &ptr = set<SPIRType>(ptr_type_id, get<SPIRType>(mbr_type_id));
  						ptr.self = mbr_type_id;
  						ptr.storage = var.storage;
  						ptr.pointer = true;
  						ptr.pointer_depth++;
  						ptr.parent_type = mbr_type_id;
  
  						func.add_parameter(mbr_type_id, var_id, true);
  						set<SPIRVariable>(var_id, ptr_type_id, StorageClassFunction);
  						ir.meta[var_id].decoration = ir.meta[type_id].members[mbr_idx];
  					}
  					mbr_idx++;
  				}
  			}
  			else
  			{
  				uint32_t next_id = ir.increase_bound_by(1);
  				func.add_parameter(type_id, next_id, true);
  				set<SPIRVariable>(next_id, type_id, StorageClassFunction, 0, arg_id);
  
  				// Ensure the existing variable has a valid name and the new variable has all the same meta info
  				set_name(arg_id, ensure_valid_name(to_name(arg_id), "v"));
  				ir.meta[next_id] = ir.meta[arg_id];
  			}
  		}
  	}
  }
  
  // For all variables that are some form of non-input-output interface block, mark that all the structs
  // that are recursively contained within the type referenced by that variable should be packed tightly.
  void CompilerMSL::mark_packable_structs()
  {
  	ir.for_each_typed_id<SPIRVariable>([&](uint32_t, SPIRVariable &var) {
  		if (var.storage != StorageClassFunction && !is_hidden_variable(var))
  		{
  			auto &type = this->get<SPIRType>(var.basetype);
  			if (type.pointer &&
  			    (type.storage == StorageClassUniform || type.storage == StorageClassUniformConstant ||
  			     type.storage == StorageClassPushConstant || type.storage == StorageClassStorageBuffer) &&
  			    (has_decoration(type.self, DecorationBlock) || has_decoration(type.self, DecorationBufferBlock)))
  				mark_as_packable(type);
  		}
  	});
  }
  
  // If the specified type is a struct, it and any nested structs
  // are marked as packable with the SPIRVCrossDecorationBufferBlockRepacked decoration,
  void CompilerMSL::mark_as_packable(SPIRType &type)
  {
  	// If this is not the base type (eg. it's a pointer or array), tunnel down
  	if (type.parent_type)
  	{
  		mark_as_packable(get<SPIRType>(type.parent_type));
  		return;
  	}
  
  	if (type.basetype == SPIRType::Struct)
  	{
  		set_extended_decoration(type.self, SPIRVCrossDecorationBufferBlockRepacked);
  
  		// Recurse
  		uint32_t mbr_cnt = uint32_t(type.member_types.size());
  		for (uint32_t mbr_idx = 0; mbr_idx < mbr_cnt; mbr_idx++)
  		{
  			uint32_t mbr_type_id = type.member_types[mbr_idx];
  			auto &mbr_type = get<SPIRType>(mbr_type_id);
  			mark_as_packable(mbr_type);
  			if (mbr_type.type_alias)
  			{
  				auto &mbr_type_alias = get<SPIRType>(mbr_type.type_alias);
  				mark_as_packable(mbr_type_alias);
  			}
  		}
  	}
  }
  
  // If a shader input exists at the location, it is marked as being used by this shader
  void CompilerMSL::mark_location_as_used_by_shader(uint32_t location, const SPIRType &type,
                                                    StorageClass storage, bool fallback)
  {
  	if (storage != StorageClassInput)
  		return;
  
  	uint32_t count = type_to_location_count(type);
  	for (uint32_t i = 0; i < count; i++)
  	{
  		location_inputs_in_use.insert(location + i);
  		if (fallback)
  			location_inputs_in_use_fallback.insert(location + i);
  	}
  }
  
  uint32_t CompilerMSL::get_target_components_for_fragment_location(uint32_t location) const
  {
  	auto itr = fragment_output_components.find(location);
  	if (itr == end(fragment_output_components))
  		return 4;
  	else
  		return itr->second;
  }
  
  uint32_t CompilerMSL::build_extended_vector_type(uint32_t type_id, uint32_t components, SPIRType::BaseType basetype)
  {
  	uint32_t new_type_id = ir.increase_bound_by(1);
  	auto &old_type = get<SPIRType>(type_id);
  	auto *type = &set<SPIRType>(new_type_id, old_type);
  	type->vecsize = components;
  	if (basetype != SPIRType::Unknown)
  		type->basetype = basetype;
  	type->self = new_type_id;
  	type->parent_type = type_id;
  	type->array.clear();
  	type->array_size_literal.clear();
  	type->pointer = false;
  
  	if (is_array(old_type))
  	{
  		uint32_t array_type_id = ir.increase_bound_by(1);
  		type = &set<SPIRType>(array_type_id, *type);
  		type->parent_type = new_type_id;
  		type->array = old_type.array;
  		type->array_size_literal = old_type.array_size_literal;
  		new_type_id = array_type_id;
  	}
  
  	if (old_type.pointer)
  	{
  		uint32_t ptr_type_id = ir.increase_bound_by(1);
  		type = &set<SPIRType>(ptr_type_id, *type);
  		type->self = new_type_id;
  		type->parent_type = new_type_id;
  		type->storage = old_type.storage;
  		type->pointer = true;
  		type->pointer_depth++;
  		new_type_id = ptr_type_id;
  	}
  
  	return new_type_id;
  }
  
  uint32_t CompilerMSL::build_msl_interpolant_type(uint32_t type_id, bool is_noperspective)
  {
  	uint32_t new_type_id = ir.increase_bound_by(1);
  	SPIRType &type = set<SPIRType>(new_type_id, get<SPIRType>(type_id));
  	type.basetype = SPIRType::Interpolant;
  	type.parent_type = type_id;
  	// In Metal, the pull-model interpolant type encodes perspective-vs-no-perspective in the type itself.
  	// Add this decoration so we know which argument to pass to the template.
  	if (is_noperspective)
  		set_decoration(new_type_id, DecorationNoPerspective);
  	return new_type_id;
  }
  
  bool CompilerMSL::add_component_variable_to_interface_block(spv::StorageClass storage, const std::string &ib_var_ref,
                                                              SPIRVariable &var,
                                                              const SPIRType &type,
                                                              InterfaceBlockMeta &meta)
  {
  	// Deal with Component decorations.
  	const InterfaceBlockMeta::LocationMeta *location_meta = nullptr;
  	uint32_t location = ~0u;
  	if (has_decoration(var.self, DecorationLocation))
  	{
  		location = get_decoration(var.self, DecorationLocation);
  		auto location_meta_itr = meta.location_meta.find(location);
  		if (location_meta_itr != end(meta.location_meta))
  			location_meta = &location_meta_itr->second;
  	}
  
  	// Check if we need to pad fragment output to match a certain number of components.
  	if (location_meta)
  	{
  		bool pad_fragment_output = has_decoration(var.self, DecorationLocation) &&
  		                           msl_options.pad_fragment_output_components &&
  		                           get_entry_point().model == ExecutionModelFragment && storage == StorageClassOutput;
  
  		auto &entry_func = get<SPIRFunction>(ir.default_entry_point);
  		uint32_t start_component = get_decoration(var.self, DecorationComponent);
  		uint32_t type_components = type.vecsize;
  		uint32_t num_components = location_meta->num_components;
  
  		if (pad_fragment_output)
  		{
  			uint32_t locn = get_decoration(var.self, DecorationLocation);
  			num_components = std::max(num_components, get_target_components_for_fragment_location(locn));
  		}
  
  		// We have already declared an IO block member as m_location_N.
  		// Just emit an early-declared variable and fixup as needed.
  		// Arrays need to be unrolled here since each location might need a different number of components.
  		entry_func.add_local_variable(var.self);
  		vars_needing_early_declaration.push_back(var.self);
  
  		if (var.storage == StorageClassInput)
  		{
  			entry_func.fixup_hooks_in.push_back([=, &type, &var]() {
  				if (!type.array.empty())
  				{
  					uint32_t array_size = to_array_size_literal(type);
  					for (uint32_t loc_off = 0; loc_off < array_size; loc_off++)
  					{
  						statement(to_name(var.self), "[", loc_off, "]", " = ", ib_var_ref,
  						          ".m_location_", location + loc_off,
  						          vector_swizzle(type_components, start_component), ";");
  					}
  				}
  				else
  				{
  					statement(to_name(var.self), " = ", ib_var_ref, ".m_location_", location,
  					          vector_swizzle(type_components, start_component), ";");
  				}
  			});
  		}
  		else
  		{
  			entry_func.fixup_hooks_out.push_back([=, &type, &var]() {
  				if (!type.array.empty())
  				{
  					uint32_t array_size = to_array_size_literal(type);
  					for (uint32_t loc_off = 0; loc_off < array_size; loc_off++)
  					{
  						statement(ib_var_ref, ".m_location_", location + loc_off,
  						          vector_swizzle(type_components, start_component), " = ",
  						          to_name(var.self), "[", loc_off, "];");
  					}
  				}
  				else
  				{
  					statement(ib_var_ref, ".m_location_", location,
  					          vector_swizzle(type_components, start_component), " = ", to_name(var.self), ";");
  				}
  			});
  		}
  		return true;
  	}
  	else
  		return false;
  }
  
  void CompilerMSL::add_plain_variable_to_interface_block(StorageClass storage, const string &ib_var_ref,
                                                          SPIRType &ib_type, SPIRVariable &var, InterfaceBlockMeta &meta)
  {
  	bool is_builtin = is_builtin_variable(var);
  	BuiltIn builtin = BuiltIn(get_decoration(var.self, DecorationBuiltIn));
  	bool is_flat = has_decoration(var.self, DecorationFlat);
  	bool is_noperspective = has_decoration(var.self, DecorationNoPerspective);
  	bool is_centroid = has_decoration(var.self, DecorationCentroid);
  	bool is_sample = has_decoration(var.self, DecorationSample);
  
  	// Add a reference to the variable type to the interface struct.
  	uint32_t ib_mbr_idx = uint32_t(ib_type.member_types.size());
  	uint32_t type_id = ensure_correct_builtin_type(var.basetype, builtin);
  	var.basetype = type_id;
  
  	type_id = get_pointee_type_id(var.basetype);
  	if (meta.strip_array && is_array(get<SPIRType>(type_id)))
  		type_id = get<SPIRType>(type_id).parent_type;
  	auto &type = get<SPIRType>(type_id);
  	uint32_t target_components = 0;
  	uint32_t type_components = type.vecsize;
  
  	bool padded_output = false;
  	bool padded_input = false;
  	uint32_t start_component = 0;
  
  	auto &entry_func = get<SPIRFunction>(ir.default_entry_point);
  
  	if (add_component_variable_to_interface_block(storage, ib_var_ref, var, type, meta))
  		return;
  
  	bool pad_fragment_output = has_decoration(var.self, DecorationLocation) &&
  	                           msl_options.pad_fragment_output_components &&
  	                           get_entry_point().model == ExecutionModelFragment && storage == StorageClassOutput;
  
  	if (pad_fragment_output)
  	{
  		uint32_t locn = get_decoration(var.self, DecorationLocation);
  		target_components = get_target_components_for_fragment_location(locn);
  		if (type_components < target_components)
  		{
  			// Make a new type here.
  			type_id = build_extended_vector_type(type_id, target_components);
  			padded_output = true;
  		}
  	}
  
  	if (storage == StorageClassInput && pull_model_inputs.count(var.self))
  		ib_type.member_types.push_back(build_msl_interpolant_type(type_id, is_noperspective));
  	else
  		ib_type.member_types.push_back(type_id);
  
  	// Give the member a name
  	string mbr_name = ensure_valid_name(to_expression(var.self), "m");
  	set_member_name(ib_type.self, ib_mbr_idx, mbr_name);
  
  	// Update the original variable reference to include the structure reference
  	string qual_var_name = ib_var_ref + "." + mbr_name;
  	// If using pull-model interpolation, need to add a call to the correct interpolation method.
  	if (storage == StorageClassInput && pull_model_inputs.count(var.self))
  	{
  		if (is_centroid)
  			qual_var_name += ".interpolate_at_centroid()";
  		else if (is_sample)
  			qual_var_name += join(".interpolate_at_sample(", to_expression(builtin_sample_id_id), ")");
  		else
  			qual_var_name += ".interpolate_at_center()";
  	}
  
  	if (padded_output || padded_input)
  	{
  		entry_func.add_local_variable(var.self);
  		vars_needing_early_declaration.push_back(var.self);
  
  		if (padded_output)
  		{
  			entry_func.fixup_hooks_out.push_back([=, &var]() {
  				statement(qual_var_name, vector_swizzle(type_components, start_component), " = ", to_name(var.self),
  				          ";");
  			});
  		}
  		else
  		{
  			entry_func.fixup_hooks_in.push_back([=, &var]() {
  				statement(to_name(var.self), " = ", qual_var_name, vector_swizzle(type_components, start_component),
  				          ";");
  			});
  		}
  	}
  	else if (!meta.strip_array)
  		ir.meta[var.self].decoration.qualified_alias = qual_var_name;
  
  	if (var.storage == StorageClassOutput && var.initializer != ID(0))
  	{
  		if (padded_output || padded_input)
  		{
  			entry_func.fixup_hooks_in.push_back(
  			    [=, &var]() { statement(to_name(var.self), " = ", to_expression(var.initializer), ";"); });
  		}
  		else
  		{
  			if (meta.strip_array)
  			{
  				entry_func.fixup_hooks_in.push_back([=, &var]() {
  					uint32_t index = get_extended_decoration(var.self, SPIRVCrossDecorationInterfaceMemberIndex);
  					auto invocation = to_tesc_invocation_id();
  					statement(to_expression(stage_out_ptr_var_id), "[",
  					          invocation, "].",
  					          to_member_name(ib_type, index), " = ", to_expression(var.initializer), "[",
  					          invocation, "];");
  				});
  			}
  			else
  			{
  				entry_func.fixup_hooks_in.push_back([=, &var]() {
  					statement(qual_var_name, " = ", to_expression(var.initializer), ";");
  				});
  			}
  		}
  	}
  
  	// Copy the variable location from the original variable to the member
  	if (get_decoration_bitset(var.self).get(DecorationLocation))
  	{
  		uint32_t locn = get_decoration(var.self, DecorationLocation);
  		if (storage == StorageClassInput)
  		{
  			type_id = ensure_correct_input_type(var.basetype, locn, 0, meta.strip_array);
  			var.basetype = type_id;
  
  			type_id = get_pointee_type_id(type_id);
  			if (meta.strip_array && is_array(get<SPIRType>(type_id)))
  				type_id = get<SPIRType>(type_id).parent_type;
  			if (pull_model_inputs.count(var.self))
  				ib_type.member_types[ib_mbr_idx] = build_msl_interpolant_type(type_id, is_noperspective);
  			else
  				ib_type.member_types[ib_mbr_idx] = type_id;
  		}
  		set_member_decoration(ib_type.self, ib_mbr_idx, DecorationLocation, locn);
  		mark_location_as_used_by_shader(locn, get<SPIRType>(type_id), storage);
  	}
  	else if (is_builtin && is_tessellation_shader() && inputs_by_builtin.count(builtin))
  	{
  		uint32_t locn = inputs_by_builtin[builtin].location;
  		set_member_decoration(ib_type.self, ib_mbr_idx, DecorationLocation, locn);
  		mark_location_as_used_by_shader(locn, type, storage);
  	}
  
  	if (get_decoration_bitset(var.self).get(DecorationComponent))
  	{
  		uint32_t component = get_decoration(var.self, DecorationComponent);
  		set_member_decoration(ib_type.self, ib_mbr_idx, DecorationComponent, component);
  	}
  
  	if (get_decoration_bitset(var.self).get(DecorationIndex))
  	{
  		uint32_t index = get_decoration(var.self, DecorationIndex);
  		set_member_decoration(ib_type.self, ib_mbr_idx, DecorationIndex, index);
  	}
  
  	// Mark the member as builtin if needed
  	if (is_builtin)
  	{
  		set_member_decoration(ib_type.self, ib_mbr_idx, DecorationBuiltIn, builtin);
  		if (builtin == BuiltInPosition && storage == StorageClassOutput)
  			qual_pos_var_name = qual_var_name;
  	}
  
  	// Copy interpolation decorations if needed
  	if (storage != StorageClassInput || !pull_model_inputs.count(var.self))
  	{
  		if (is_flat)
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationFlat);
  		if (is_noperspective)
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationNoPerspective);
  		if (is_centroid)
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationCentroid);
  		if (is_sample)
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationSample);
  	}
  
  	set_extended_member_decoration(ib_type.self, ib_mbr_idx, SPIRVCrossDecorationInterfaceOrigID, var.self);
  }
  
  void CompilerMSL::add_composite_variable_to_interface_block(StorageClass storage, const string &ib_var_ref,
                                                              SPIRType &ib_type, SPIRVariable &var,
                                                              InterfaceBlockMeta &meta)
  {
  	auto &entry_func = get<SPIRFunction>(ir.default_entry_point);
  	auto &var_type = meta.strip_array ? get_variable_element_type(var) : get_variable_data_type(var);
  	uint32_t elem_cnt = 0;
  
  	if (add_component_variable_to_interface_block(storage, ib_var_ref, var, var_type, meta))
  		return;
  
  	if (is_matrix(var_type))
  	{
  		if (is_array(var_type))
  			SPIRV_CROSS_THROW("MSL cannot emit arrays-of-matrices in input and output variables.");
  
  		elem_cnt = var_type.columns;
  	}
  	else if (is_array(var_type))
  	{
  		if (var_type.array.size() != 1)
  			SPIRV_CROSS_THROW("MSL cannot emit arrays-of-arrays in input and output variables.");
  
  		elem_cnt = to_array_size_literal(var_type);
  	}
  
  	bool is_builtin = is_builtin_variable(var);
  	BuiltIn builtin = BuiltIn(get_decoration(var.self, DecorationBuiltIn));
  	bool is_flat = has_decoration(var.self, DecorationFlat);
  	bool is_noperspective = has_decoration(var.self, DecorationNoPerspective);
  	bool is_centroid = has_decoration(var.self, DecorationCentroid);
  	bool is_sample = has_decoration(var.self, DecorationSample);
  
  	auto *usable_type = &var_type;
  	if (usable_type->pointer)
  		usable_type = &get<SPIRType>(usable_type->parent_type);
  	while (is_array(*usable_type) || is_matrix(*usable_type))
  		usable_type = &get<SPIRType>(usable_type->parent_type);
  
  	// If a builtin, force it to have the proper name.
  	if (is_builtin)
  		set_name(var.self, builtin_to_glsl(builtin, StorageClassFunction));
  
  	bool flatten_from_ib_var = false;
  	string flatten_from_ib_mbr_name;
  
  	if (storage == StorageClassOutput && is_builtin && builtin == BuiltInClipDistance)
  	{
  		// Also declare [[clip_distance]] attribute here.
  		uint32_t clip_array_mbr_idx = uint32_t(ib_type.member_types.size());
  		ib_type.member_types.push_back(get_variable_data_type_id(var));
  		set_member_decoration(ib_type.self, clip_array_mbr_idx, DecorationBuiltIn, BuiltInClipDistance);
  
  		flatten_from_ib_mbr_name = builtin_to_glsl(BuiltInClipDistance, StorageClassOutput);
  		set_member_name(ib_type.self, clip_array_mbr_idx, flatten_from_ib_mbr_name);
  
  		// When we flatten, we flatten directly from the "out" struct,
  		// not from a function variable.
  		flatten_from_ib_var = true;
  
  		if (!msl_options.enable_clip_distance_user_varying)
  			return;
  	}
  	else if (!meta.strip_array)
  	{
  		// Only flatten/unflatten IO composites for non-tessellation cases where arrays are not stripped.
  		entry_func.add_local_variable(var.self);
  		// We need to declare the variable early and at entry-point scope.
  		vars_needing_early_declaration.push_back(var.self);
  	}
  
  	for (uint32_t i = 0; i < elem_cnt; i++)
  	{
  		// Add a reference to the variable type to the interface struct.
  		uint32_t ib_mbr_idx = uint32_t(ib_type.member_types.size());
  
  		uint32_t target_components = 0;
  		bool padded_output = false;
  		uint32_t type_id = usable_type->self;
  
  		// Check if we need to pad fragment output to match a certain number of components.
  		if (get_decoration_bitset(var.self).get(DecorationLocation) && msl_options.pad_fragment_output_components &&
  		    get_entry_point().model == ExecutionModelFragment && storage == StorageClassOutput)
  		{
  			uint32_t locn = get_decoration(var.self, DecorationLocation) + i;
  			target_components = get_target_components_for_fragment_location(locn);
  			if (usable_type->vecsize < target_components)
  			{
  				// Make a new type here.
  				type_id = build_extended_vector_type(usable_type->self, target_components);
  				padded_output = true;
  			}
  		}
  
  		if (storage == StorageClassInput && pull_model_inputs.count(var.self))
  			ib_type.member_types.push_back(build_msl_interpolant_type(get_pointee_type_id(type_id), is_noperspective));
  		else
  			ib_type.member_types.push_back(get_pointee_type_id(type_id));
  
  		// Give the member a name
  		string mbr_name = ensure_valid_name(join(to_expression(var.self), "_", i), "m");
  		set_member_name(ib_type.self, ib_mbr_idx, mbr_name);
  
  		// There is no qualified alias since we need to flatten the internal array on return.
  		if (get_decoration_bitset(var.self).get(DecorationLocation))
  		{
  			uint32_t locn = get_decoration(var.self, DecorationLocation) + i;
  			uint32_t comp = get_decoration(var.self, DecorationComponent);
  			if (storage == StorageClassInput)
  			{
  				var.basetype = ensure_correct_input_type(var.basetype, locn, 0, meta.strip_array);
  				uint32_t mbr_type_id = ensure_correct_input_type(usable_type->self, locn, 0, meta.strip_array);
  				if (storage == StorageClassInput && pull_model_inputs.count(var.self))
  					ib_type.member_types[ib_mbr_idx] = build_msl_interpolant_type(mbr_type_id, is_noperspective);
  				else
  					ib_type.member_types[ib_mbr_idx] = mbr_type_id;
  			}
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationLocation, locn);
  			if (comp)
  				set_member_decoration(ib_type.self, ib_mbr_idx, DecorationComponent, comp);
  			mark_location_as_used_by_shader(locn, *usable_type, storage);
  		}
  		else if (is_builtin && is_tessellation_shader() && inputs_by_builtin.count(builtin))
  		{
  			uint32_t locn = inputs_by_builtin[builtin].location + i;
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationLocation, locn);
  			mark_location_as_used_by_shader(locn, *usable_type, storage);
  		}
  		else if (is_builtin && (builtin == BuiltInClipDistance || builtin == BuiltInCullDistance))
  		{
  			// Declare the Clip/CullDistance as [[user(clip/cullN)]].
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationBuiltIn, builtin);
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationIndex, i);
  		}
  
  		if (get_decoration_bitset(var.self).get(DecorationIndex))
  		{
  			uint32_t index = get_decoration(var.self, DecorationIndex);
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationIndex, index);
  		}
  
  		if (storage != StorageClassInput || !pull_model_inputs.count(var.self))
  		{
  			// Copy interpolation decorations if needed
  			if (is_flat)
  				set_member_decoration(ib_type.self, ib_mbr_idx, DecorationFlat);
  			if (is_noperspective)
  				set_member_decoration(ib_type.self, ib_mbr_idx, DecorationNoPerspective);
  			if (is_centroid)
  				set_member_decoration(ib_type.self, ib_mbr_idx, DecorationCentroid);
  			if (is_sample)
  				set_member_decoration(ib_type.self, ib_mbr_idx, DecorationSample);
  		}
  
  		set_extended_member_decoration(ib_type.self, ib_mbr_idx, SPIRVCrossDecorationInterfaceOrigID, var.self);
  
  		// Only flatten/unflatten IO composites for non-tessellation cases where arrays are not stripped.
  		if (!meta.strip_array)
  		{
  			switch (storage)
  			{
  			case StorageClassInput:
  				entry_func.fixup_hooks_in.push_back([=, &var]() {
  					if (pull_model_inputs.count(var.self))
  					{
  						string lerp_call;
  						if (is_centroid)
  							lerp_call = ".interpolate_at_centroid()";
  						else if (is_sample)
  							lerp_call = join(".interpolate_at_sample(", to_expression(builtin_sample_id_id), ")");
  						else
  							lerp_call = ".interpolate_at_center()";
  						statement(to_name(var.self), "[", i, "] = ", ib_var_ref, ".", mbr_name, lerp_call, ";");
  					}
  					else
  					{
  						statement(to_name(var.self), "[", i, "] = ", ib_var_ref, ".", mbr_name, ";");
  					}
  				});
  				break;
  
  			case StorageClassOutput:
  				entry_func.fixup_hooks_out.push_back([=, &var]() {
  					if (padded_output)
  					{
  						auto &padded_type = this->get<SPIRType>(type_id);
  						statement(
  						    ib_var_ref, ".", mbr_name, " = ",
  						    remap_swizzle(padded_type, usable_type->vecsize, join(to_name(var.self), "[", i, "]")),
  						    ";");
  					}
  					else if (flatten_from_ib_var)
  						statement(ib_var_ref, ".", mbr_name, " = ", ib_var_ref, ".", flatten_from_ib_mbr_name, "[", i,
  						          "];");
  					else
  						statement(ib_var_ref, ".", mbr_name, " = ", to_name(var.self), "[", i, "];");
  				});
  				break;
  
  			default:
  				break;
  			}
  		}
  	}
  }
  
  void CompilerMSL::add_composite_member_variable_to_interface_block(StorageClass storage, const string &ib_var_ref,
                                                                     SPIRType &ib_type, SPIRVariable &var,
                                                                     uint32_t mbr_idx, InterfaceBlockMeta &meta)
  {
  	auto &entry_func = get<SPIRFunction>(ir.default_entry_point);
  	auto &var_type = meta.strip_array ? get_variable_element_type(var) : get_variable_data_type(var);
  
  	BuiltIn builtin = BuiltInMax;
  	bool is_builtin = is_member_builtin(var_type, mbr_idx, &builtin);
  	bool is_flat =
  	    has_member_decoration(var_type.self, mbr_idx, DecorationFlat) || has_decoration(var.self, DecorationFlat);
  	bool is_noperspective = has_member_decoration(var_type.self, mbr_idx, DecorationNoPerspective) ||
  	                        has_decoration(var.self, DecorationNoPerspective);
  	bool is_centroid = has_member_decoration(var_type.self, mbr_idx, DecorationCentroid) ||
  	                   has_decoration(var.self, DecorationCentroid);
  	bool is_sample =
  	    has_member_decoration(var_type.self, mbr_idx, DecorationSample) || has_decoration(var.self, DecorationSample);
  
  	uint32_t mbr_type_id = var_type.member_types[mbr_idx];
  	auto &mbr_type = get<SPIRType>(mbr_type_id);
  	uint32_t elem_cnt = 0;
  
  	if (is_matrix(mbr_type))
  	{
  		if (is_array(mbr_type))
  			SPIRV_CROSS_THROW("MSL cannot emit arrays-of-matrices in input and output variables.");
  
  		elem_cnt = mbr_type.columns;
  	}
  	else if (is_array(mbr_type))
  	{
  		if (mbr_type.array.size() != 1)
  			SPIRV_CROSS_THROW("MSL cannot emit arrays-of-arrays in input and output variables.");
  
  		elem_cnt = to_array_size_literal(mbr_type);
  	}
  
  	auto *usable_type = &mbr_type;
  	if (usable_type->pointer)
  		usable_type = &get<SPIRType>(usable_type->parent_type);
  	while (is_array(*usable_type) || is_matrix(*usable_type))
  		usable_type = &get<SPIRType>(usable_type->parent_type);
  
  	bool flatten_from_ib_var = false;
  	string flatten_from_ib_mbr_name;
  
  	if (storage == StorageClassOutput && is_builtin && builtin == BuiltInClipDistance)
  	{
  		// Also declare [[clip_distance]] attribute here.
  		uint32_t clip_array_mbr_idx = uint32_t(ib_type.member_types.size());
  		ib_type.member_types.push_back(mbr_type_id);
  		set_member_decoration(ib_type.self, clip_array_mbr_idx, DecorationBuiltIn, BuiltInClipDistance);
  
  		flatten_from_ib_mbr_name = builtin_to_glsl(BuiltInClipDistance, StorageClassOutput);
  		set_member_name(ib_type.self, clip_array_mbr_idx, flatten_from_ib_mbr_name);
  
  		// When we flatten, we flatten directly from the "out" struct,
  		// not from a function variable.
  		flatten_from_ib_var = true;
  
  		if (!msl_options.enable_clip_distance_user_varying)
  			return;
  	}
  
  	for (uint32_t i = 0; i < elem_cnt; i++)
  	{
  		// Add a reference to the variable type to the interface struct.
  		uint32_t ib_mbr_idx = uint32_t(ib_type.member_types.size());
  		if (storage == StorageClassInput && pull_model_inputs.count(var.self))
  			ib_type.member_types.push_back(build_msl_interpolant_type(usable_type->self, is_noperspective));
  		else
  			ib_type.member_types.push_back(usable_type->self);
  
  		// Give the member a name
  		string mbr_name = ensure_valid_name(join(to_qualified_member_name(var_type, mbr_idx), "_", i), "m");
  		set_member_name(ib_type.self, ib_mbr_idx, mbr_name);
  
  		if (has_member_decoration(var_type.self, mbr_idx, DecorationLocation))
  		{
  			uint32_t locn = get_member_decoration(var_type.self, mbr_idx, DecorationLocation) + i;
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationLocation, locn);
  			mark_location_as_used_by_shader(locn, *usable_type, storage);
  		}
  		else if (has_decoration(var.self, DecorationLocation))
  		{
  			uint32_t locn = get_accumulated_member_location(var, mbr_idx, meta.strip_array) + i;
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationLocation, locn);
  			mark_location_as_used_by_shader(locn, *usable_type, storage);
  		}
  		else if (is_builtin && is_tessellation_shader() && inputs_by_builtin.count(builtin))
  		{
  			uint32_t locn = inputs_by_builtin[builtin].location + i;
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationLocation, locn);
  			mark_location_as_used_by_shader(locn, *usable_type, storage);
  		}
  		else if (is_builtin && (builtin == BuiltInClipDistance || builtin == BuiltInCullDistance))
  		{
  			// Declare the Clip/CullDistance as [[user(clip/cullN)]].
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationBuiltIn, builtin);
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationIndex, i);
  		}
  
  		if (has_member_decoration(var_type.self, mbr_idx, DecorationComponent))
  			SPIRV_CROSS_THROW("DecorationComponent on matrices and arrays make little sense.");
  
  		if (storage != StorageClassInput || !pull_model_inputs.count(var.self))
  		{
  			// Copy interpolation decorations if needed
  			if (is_flat)
  				set_member_decoration(ib_type.self, ib_mbr_idx, DecorationFlat);
  			if (is_noperspective)
  				set_member_decoration(ib_type.self, ib_mbr_idx, DecorationNoPerspective);
  			if (is_centroid)
  				set_member_decoration(ib_type.self, ib_mbr_idx, DecorationCentroid);
  			if (is_sample)
  				set_member_decoration(ib_type.self, ib_mbr_idx, DecorationSample);
  		}
  
  		set_extended_member_decoration(ib_type.self, ib_mbr_idx, SPIRVCrossDecorationInterfaceOrigID, var.self);
  		set_extended_member_decoration(ib_type.self, ib_mbr_idx, SPIRVCrossDecorationInterfaceMemberIndex, mbr_idx);
  
  		// Unflatten or flatten from [[stage_in]] or [[stage_out]] as appropriate.
  		if (!meta.strip_array && meta.allow_local_declaration)
  		{
  			switch (storage)
  			{
  			case StorageClassInput:
  				entry_func.fixup_hooks_in.push_back([=, &var, &var_type]() {
  					if (pull_model_inputs.count(var.self))
  					{
  						string lerp_call;
  						if (is_centroid)
  							lerp_call = ".interpolate_at_centroid()";
  						else if (is_sample)
  							lerp_call = join(".interpolate_at_sample(", to_expression(builtin_sample_id_id), ")");
  						else
  							lerp_call = ".interpolate_at_center()";
  						statement(to_name(var.self), ".", to_member_name(var_type, mbr_idx), "[", i, "] = ", ib_var_ref,
  						          ".", mbr_name, lerp_call, ";");
  					}
  					else
  					{
  						statement(to_name(var.self), ".", to_member_name(var_type, mbr_idx), "[", i, "] = ", ib_var_ref,
  						          ".", mbr_name, ";");
  					}
  				});
  				break;
  
  			case StorageClassOutput:
  				entry_func.fixup_hooks_out.push_back([=, &var, &var_type]() {
  					if (flatten_from_ib_var)
  					{
  						statement(ib_var_ref, ".", mbr_name, " = ", ib_var_ref, ".", flatten_from_ib_mbr_name, "[", i,
  						          "];");
  					}
  					else
  					{
  						statement(ib_var_ref, ".", mbr_name, " = ", to_name(var.self), ".",
  						          to_member_name(var_type, mbr_idx), "[", i, "];");
  					}
  				});
  				break;
  
  			default:
  				break;
  			}
  		}
  	}
  }
  
  void CompilerMSL::add_plain_member_variable_to_interface_block(StorageClass storage, const string &ib_var_ref,
                                                                 SPIRType &ib_type, SPIRVariable &var, uint32_t mbr_idx,
                                                                 InterfaceBlockMeta &meta)
  {
  	auto &var_type = meta.strip_array ? get_variable_element_type(var) : get_variable_data_type(var);
  	auto &entry_func = get<SPIRFunction>(ir.default_entry_point);
  
  	BuiltIn builtin = BuiltInMax;
  	bool is_builtin = is_member_builtin(var_type, mbr_idx, &builtin);
  	bool is_flat =
  	    has_member_decoration(var_type.self, mbr_idx, DecorationFlat) || has_decoration(var.self, DecorationFlat);
  	bool is_noperspective = has_member_decoration(var_type.self, mbr_idx, DecorationNoPerspective) ||
  	                        has_decoration(var.self, DecorationNoPerspective);
  	bool is_centroid = has_member_decoration(var_type.self, mbr_idx, DecorationCentroid) ||
  	                   has_decoration(var.self, DecorationCentroid);
  	bool is_sample =
  	    has_member_decoration(var_type.self, mbr_idx, DecorationSample) || has_decoration(var.self, DecorationSample);
  
  	// Add a reference to the member to the interface struct.
  	uint32_t mbr_type_id = var_type.member_types[mbr_idx];
  	uint32_t ib_mbr_idx = uint32_t(ib_type.member_types.size());
  	mbr_type_id = ensure_correct_builtin_type(mbr_type_id, builtin);
  	var_type.member_types[mbr_idx] = mbr_type_id;
  	if (storage == StorageClassInput && pull_model_inputs.count(var.self))
  		ib_type.member_types.push_back(build_msl_interpolant_type(mbr_type_id, is_noperspective));
  	else
  		ib_type.member_types.push_back(mbr_type_id);
  
  	// Give the member a name
  	string mbr_name = ensure_valid_name(to_qualified_member_name(var_type, mbr_idx), "m");
  	set_member_name(ib_type.self, ib_mbr_idx, mbr_name);
  
  	// Update the original variable reference to include the structure reference
  	string qual_var_name = ib_var_ref + "." + mbr_name;
  	// If using pull-model interpolation, need to add a call to the correct interpolation method.
  	if (storage == StorageClassInput && pull_model_inputs.count(var.self))
  	{
  		if (is_centroid)
  			qual_var_name += ".interpolate_at_centroid()";
  		else if (is_sample)
  			qual_var_name += join(".interpolate_at_sample(", to_expression(builtin_sample_id_id), ")");
  		else
  			qual_var_name += ".interpolate_at_center()";
  	}
  
  	bool flatten_stage_out = false;
  
  	if (is_builtin && !meta.strip_array)
  	{
  		// For the builtin gl_PerVertex, we cannot treat it as a block anyways,
  		// so redirect to qualified name.
  		set_member_qualified_name(var_type.self, mbr_idx, qual_var_name);
  	}
  	else if (!meta.strip_array && meta.allow_local_declaration)
  	{
  		// Unflatten or flatten from [[stage_in]] or [[stage_out]] as appropriate.
  		switch (storage)
  		{
  		case StorageClassInput:
  			entry_func.fixup_hooks_in.push_back([=, &var, &var_type]() {
  				statement(to_name(var.self), ".", to_member_name(var_type, mbr_idx), " = ", qual_var_name, ";");
  			});
  			break;
  
  		case StorageClassOutput:
  			flatten_stage_out = true;
  			entry_func.fixup_hooks_out.push_back([=, &var, &var_type]() {
  				statement(qual_var_name, " = ", to_name(var.self), ".", to_member_name(var_type, mbr_idx), ";");
  			});
  			break;
  
  		default:
  			break;
  		}
  	}
  
  	// Copy the variable location from the original variable to the member
  	if (has_member_decoration(var_type.self, mbr_idx, DecorationLocation))
  	{
  		uint32_t locn = get_member_decoration(var_type.self, mbr_idx, DecorationLocation);
  		if (storage == StorageClassInput)
  		{
  			mbr_type_id = ensure_correct_input_type(mbr_type_id, locn, 0, meta.strip_array);
  			var_type.member_types[mbr_idx] = mbr_type_id;
  			if (storage == StorageClassInput && pull_model_inputs.count(var.self))
  				ib_type.member_types[ib_mbr_idx] = build_msl_interpolant_type(mbr_type_id, is_noperspective);
  			else
  				ib_type.member_types[ib_mbr_idx] = mbr_type_id;
  		}
  		set_member_decoration(ib_type.self, ib_mbr_idx, DecorationLocation, locn);
  		mark_location_as_used_by_shader(locn, get<SPIRType>(mbr_type_id), storage);
  	}
  	else if (has_decoration(var.self, DecorationLocation))
  	{
  		// The block itself might have a location and in this case, all members of the block
  		// receive incrementing locations.
  		uint32_t locn = get_accumulated_member_location(var, mbr_idx, meta.strip_array);
  		if (storage == StorageClassInput)
  		{
  			mbr_type_id = ensure_correct_input_type(mbr_type_id, locn, 0, meta.strip_array);
  			var_type.member_types[mbr_idx] = mbr_type_id;
  			if (storage == StorageClassInput && pull_model_inputs.count(var.self))
  				ib_type.member_types[ib_mbr_idx] = build_msl_interpolant_type(mbr_type_id, is_noperspective);
  			else
  				ib_type.member_types[ib_mbr_idx] = mbr_type_id;
  		}
  		set_member_decoration(ib_type.self, ib_mbr_idx, DecorationLocation, locn);
  		mark_location_as_used_by_shader(locn, get<SPIRType>(mbr_type_id), storage);
  	}
  	else if (is_builtin && is_tessellation_shader() && inputs_by_builtin.count(builtin))
  	{
  		uint32_t locn = 0;
  		auto builtin_itr = inputs_by_builtin.find(builtin);
  		if (builtin_itr != end(inputs_by_builtin))
  			locn = builtin_itr->second.location;
  		set_member_decoration(ib_type.self, ib_mbr_idx, DecorationLocation, locn);
  		mark_location_as_used_by_shader(locn, get<SPIRType>(mbr_type_id), storage);
  	}
  
  	// Copy the component location, if present.
  	if (has_member_decoration(var_type.self, mbr_idx, DecorationComponent))
  	{
  		uint32_t comp = get_member_decoration(var_type.self, mbr_idx, DecorationComponent);
  		set_member_decoration(ib_type.self, ib_mbr_idx, DecorationComponent, comp);
  	}
  
  	// Mark the member as builtin if needed
  	if (is_builtin)
  	{
  		set_member_decoration(ib_type.self, ib_mbr_idx, DecorationBuiltIn, builtin);
  		if (builtin == BuiltInPosition && storage == StorageClassOutput)
  			qual_pos_var_name = qual_var_name;
  	}
  
  	const SPIRConstant *c = nullptr;
  	if (!flatten_stage_out && var.storage == StorageClassOutput &&
  	    var.initializer != ID(0) && (c = maybe_get<SPIRConstant>(var.initializer)))
  	{
  		if (meta.strip_array)
  		{
  			entry_func.fixup_hooks_in.push_back([=, &var]() {
  				auto &type = this->get<SPIRType>(var.basetype);
  				uint32_t index = get_extended_member_decoration(var.self, mbr_idx, SPIRVCrossDecorationInterfaceMemberIndex);
  
  				auto invocation = to_tesc_invocation_id();
  				auto constant_chain = join(to_expression(var.initializer), "[", invocation, "]");
  				statement(to_expression(stage_out_ptr_var_id), "[",
  				          invocation, "].",
  				          to_member_name(ib_type, index), " = ",
  				          constant_chain, ".", to_member_name(type, mbr_idx), ";");
  			});
  		}
  		else
  		{
  			entry_func.fixup_hooks_in.push_back([=]() {
  				statement(qual_var_name, " = ", constant_expression(
  						this->get<SPIRConstant>(c->subconstants[mbr_idx])), ";");
  			});
  		}
  	}
  
  	if (storage != StorageClassInput || !pull_model_inputs.count(var.self))
  	{
  		// Copy interpolation decorations if needed
  		if (is_flat)
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationFlat);
  		if (is_noperspective)
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationNoPerspective);
  		if (is_centroid)
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationCentroid);
  		if (is_sample)
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationSample);
  	}
  
  	set_extended_member_decoration(ib_type.self, ib_mbr_idx, SPIRVCrossDecorationInterfaceOrigID, var.self);
  	set_extended_member_decoration(ib_type.self, ib_mbr_idx, SPIRVCrossDecorationInterfaceMemberIndex, mbr_idx);
  }
  
  // In Metal, the tessellation levels are stored as tightly packed half-precision floating point values.
  // But, stage-in attribute offsets and strides must be multiples of four, so we can't pass the levels
  // individually. Therefore, we must pass them as vectors. Triangles get a single float4, with the outer
  // levels in 'xyz' and the inner level in 'w'. Quads get a float4 containing the outer levels and a
  // float2 containing the inner levels.
  void CompilerMSL::add_tess_level_input_to_interface_block(const std::string &ib_var_ref, SPIRType &ib_type,
                                                            SPIRVariable &var)
  {
  	auto &entry_func = get<SPIRFunction>(ir.default_entry_point);
  	auto &var_type = get_variable_element_type(var);
  
  	BuiltIn builtin = BuiltIn(get_decoration(var.self, DecorationBuiltIn));
  
  	// Force the variable to have the proper name.
  	string var_name = builtin_to_glsl(builtin, StorageClassFunction);
  	set_name(var.self, var_name);
  
  	// We need to declare the variable early and at entry-point scope.
  	entry_func.add_local_variable(var.self);
  	vars_needing_early_declaration.push_back(var.self);
  	bool triangles = get_execution_mode_bitset().get(ExecutionModeTriangles);
  	string mbr_name;
  
  	// Add a reference to the variable type to the interface struct.
  	uint32_t ib_mbr_idx = uint32_t(ib_type.member_types.size());
  
  	const auto mark_locations = [&](const SPIRType &new_var_type) {
  		if (get_decoration_bitset(var.self).get(DecorationLocation))
  		{
  			uint32_t locn = get_decoration(var.self, DecorationLocation);
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationLocation, locn);
  			mark_location_as_used_by_shader(locn, new_var_type, StorageClassInput);
  		}
  		else if (inputs_by_builtin.count(builtin))
  		{
  			uint32_t locn = inputs_by_builtin[builtin].location;
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationLocation, locn);
  			mark_location_as_used_by_shader(locn, new_var_type, StorageClassInput);
  		}
  	};
  
  	if (triangles)
  	{
  		// Triangles are tricky, because we want only one member in the struct.
  		mbr_name = "gl_TessLevel";
  
  		// If we already added the other one, we can skip this step.
  		if (!added_builtin_tess_level)
  		{
  			uint32_t type_id = build_extended_vector_type(var_type.self, 4);
  
  			ib_type.member_types.push_back(type_id);
  
  			// Give the member a name
  			set_member_name(ib_type.self, ib_mbr_idx, mbr_name);
  
  			// We cannot decorate both, but the important part is that
  			// it's marked as builtin so we can get automatic attribute assignment if needed.
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationBuiltIn, builtin);
  
  			mark_locations(var_type);
  			added_builtin_tess_level = true;
  		}
  	}
  	else
  	{
  		mbr_name = var_name;
  
  		uint32_t type_id = build_extended_vector_type(var_type.self, builtin == BuiltInTessLevelOuter ? 4 : 2);
  
  		uint32_t ptr_type_id = ir.increase_bound_by(1);
  		auto &new_var_type = set<SPIRType>(ptr_type_id, get<SPIRType>(type_id));
  		new_var_type.pointer = true;
  		new_var_type.pointer_depth++;
  		new_var_type.storage = StorageClassInput;
  		new_var_type.parent_type = type_id;
  
  		ib_type.member_types.push_back(type_id);
  
  		// Give the member a name
  		set_member_name(ib_type.self, ib_mbr_idx, mbr_name);
  		set_member_decoration(ib_type.self, ib_mbr_idx, DecorationBuiltIn, builtin);
  
  		mark_locations(new_var_type);
  	}
  
  	if (builtin == BuiltInTessLevelOuter)
  	{
  		entry_func.fixup_hooks_in.push_back([=]() {
  			statement(var_name, "[0] = ", ib_var_ref, ".", mbr_name, ".x;");
  			statement(var_name, "[1] = ", ib_var_ref, ".", mbr_name, ".y;");
  			statement(var_name, "[2] = ", ib_var_ref, ".", mbr_name, ".z;");
  			if (!triangles)
  				statement(var_name, "[3] = ", ib_var_ref, ".", mbr_name, ".w;");
  		});
  	}
  	else
  	{
  		entry_func.fixup_hooks_in.push_back([=]() {
  			if (triangles)
  			{
  				statement(var_name, "[0] = ", ib_var_ref, ".", mbr_name, ".w;");
  			}
  			else
  			{
  				statement(var_name, "[0] = ", ib_var_ref, ".", mbr_name, ".x;");
  				statement(var_name, "[1] = ", ib_var_ref, ".", mbr_name, ".y;");
  			}
  		});
  	}
  }
  
  bool CompilerMSL::variable_storage_requires_stage_io(spv::StorageClass storage) const
  {
  	if (storage == StorageClassOutput)
  		return !capture_output_to_buffer;
  	else if (storage == StorageClassInput)
  		return !(get_execution_model() == ExecutionModelTessellationControl && msl_options.multi_patch_workgroup);
  	else
  		return false;
  }
  
  string CompilerMSL::to_tesc_invocation_id()
  {
  	if (msl_options.multi_patch_workgroup)
  	{
  		// n.b. builtin_invocation_id_id here is the dispatch global invocation ID,
  		// not the TC invocation ID.
  		return join(to_expression(builtin_invocation_id_id), ".x % ", get_entry_point().output_vertices);
  	}
  	else
  		return builtin_to_glsl(BuiltInInvocationId, StorageClassInput);
  }
  
  void CompilerMSL::emit_local_masked_variable(const SPIRVariable &masked_var, bool strip_array)
  {
  	auto &entry_func = get<SPIRFunction>(ir.default_entry_point);
  	bool threadgroup_storage = variable_decl_is_remapped_storage(masked_var, StorageClassWorkgroup);
  
  	if (threadgroup_storage && msl_options.multi_patch_workgroup)
  	{
  		// We need one threadgroup block per patch, so fake this.
  		entry_func.fixup_hooks_in.push_back([this, &masked_var]() {
  			auto &type = get_variable_data_type(masked_var);
  			add_local_variable_name(masked_var.self);
  
  			bool old_is_builtin = is_using_builtin_array;
  			is_using_builtin_array = true;
  
  			const uint32_t max_control_points_per_patch = 32u;
  			uint32_t max_num_instances =
  					(max_control_points_per_patch + get_entry_point().output_vertices - 1u) /
  					get_entry_point().output_vertices;
  			statement("threadgroup ", type_to_glsl(type), " ",
  			          "spvStorage", to_name(masked_var.self), "[", max_num_instances, "]",
  			          type_to_array_glsl(type), ";");
  
  			// Assign a threadgroup slice to each PrimitiveID.
  			// We assume here that workgroup size is rounded to 32,
  			// since that's the maximum number of control points per patch.
  			// We cannot size the array based on fixed dispatch parameters,
  			// since Metal does not allow that. :(
  			// FIXME: We will likely need an option to support passing down target workgroup size,
  			// so we can emit appropriate size here.
  			statement("threadgroup ", type_to_glsl(type), " ",
  			          "(&", to_name(masked_var.self), ")",
  			          type_to_array_glsl(type), " = spvStorage", to_name(masked_var.self), "[",
  			          "(", to_expression(builtin_invocation_id_id), ".x / ",
  			          get_entry_point().output_vertices, ") % ",
  			          max_num_instances, "];");
  
  			is_using_builtin_array = old_is_builtin;
  		});
  	}
  	else
  	{
  		entry_func.add_local_variable(masked_var.self);
  	}
  
  	if (!threadgroup_storage)
  	{
  		vars_needing_early_declaration.push_back(masked_var.self);
  	}
  	else if (masked_var.initializer)
  	{
  		// Cannot directly initialize threadgroup variables. Need fixup hooks.
  		ID initializer = masked_var.initializer;
  		if (strip_array)
  		{
  			entry_func.fixup_hooks_in.push_back([this, &masked_var, initializer]() {
  				auto invocation = to_tesc_invocation_id();
  				statement(to_expression(masked_var.self), "[",
  				          invocation, "] = ",
  				          to_expression(initializer), "[",
  				          invocation, "];");
  			});
  		}
  		else
  		{
  			entry_func.fixup_hooks_in.push_back([this, &masked_var, initializer]() {
  				statement(to_expression(masked_var.self), " = ", to_expression(initializer), ";");
  			});
  		}
  	}
  }
  
  void CompilerMSL::add_variable_to_interface_block(StorageClass storage, const string &ib_var_ref, SPIRType &ib_type,
                                                    SPIRVariable &var, InterfaceBlockMeta &meta)
  {
  	auto &entry_func = get<SPIRFunction>(ir.default_entry_point);
  	// Tessellation control I/O variables and tessellation evaluation per-point inputs are
  	// usually declared as arrays. In these cases, we want to add the element type to the
  	// interface block, since in Metal it's the interface block itself which is arrayed.
  	auto &var_type = meta.strip_array ? get_variable_element_type(var) : get_variable_data_type(var);
  	bool is_builtin = is_builtin_variable(var);
  	auto builtin = BuiltIn(get_decoration(var.self, DecorationBuiltIn));
  	bool is_block = has_decoration(var_type.self, DecorationBlock);
  
  	// If stage variables are masked out, emit them as plain variables instead.
  	// For builtins, we query them one by one later.
  	// IO blocks are not masked here, we need to mask them per-member instead.
  	if (storage == StorageClassOutput && is_stage_output_variable_masked(var))
  	{
  		// If we ignore an output, we must still emit it, since it might be used by app.
  		// Instead, just emit it as early declaration.
  		emit_local_masked_variable(var, meta.strip_array);
  		return;
  	}
  
  	if (var_type.basetype == SPIRType::Struct)
  	{
  		bool block_requires_flattening = variable_storage_requires_stage_io(storage) || is_block;
  		bool needs_local_declaration = !is_builtin && block_requires_flattening && meta.allow_local_declaration;
  
  		if (needs_local_declaration)
  		{
  			// For I/O blocks or structs, we will need to pass the block itself around
  			// to functions if they are used globally in leaf functions.
  			// Rather than passing down member by member,
  			// we unflatten I/O blocks while running the shader,
  			// and pass the actual struct type down to leaf functions.
  			// We then unflatten inputs, and flatten outputs in the "fixup" stages.
  			emit_local_masked_variable(var, meta.strip_array);
  		}
  
  		if (!block_requires_flattening)
  		{
  			// In Metal tessellation shaders, the interface block itself is arrayed. This makes things
  			// very complicated, since stage-in structures in MSL don't support nested structures.
  			// Luckily, for stage-out when capturing output, we can avoid this and just add
  			// composite members directly, because the stage-out structure is stored to a buffer,
  			// not returned.
  			add_plain_variable_to_interface_block(storage, ib_var_ref, ib_type, var, meta);
  		}
  		else
  		{
  			bool masked_block = false;
  
  			// Flatten the struct members into the interface struct
  			for (uint32_t mbr_idx = 0; mbr_idx < uint32_t(var_type.member_types.size()); mbr_idx++)
  			{
  				builtin = BuiltInMax;
  				is_builtin = is_member_builtin(var_type, mbr_idx, &builtin);
  				auto &mbr_type = get<SPIRType>(var_type.member_types[mbr_idx]);
  
  				if (storage == StorageClassOutput && is_stage_output_block_member_masked(var, mbr_idx, meta.strip_array))
  				{
  					if (is_block)
  						masked_block = true;
  
  					// Non-builtin block output variables are just ignored, since they will still access
  					// the block variable as-is. They're just not flattened.
  					if (is_builtin && !meta.strip_array)
  					{
  						// Emit a fake variable instead.
  						uint32_t ids = ir.increase_bound_by(2);
  						uint32_t ptr_type_id = ids + 0;
  						uint32_t var_id = ids + 1;
  
  						auto ptr_type = mbr_type;
  						ptr_type.pointer = true;
  						ptr_type.pointer_depth++;
  						ptr_type.parent_type = var_type.member_types[mbr_idx];
  						ptr_type.storage = StorageClassOutput;
  
  						uint32_t initializer = 0;
  						if (var.initializer)
  							if (auto *c = maybe_get<SPIRConstant>(var.initializer))
  								initializer = c->subconstants[mbr_idx];
  
  						set<SPIRType>(ptr_type_id, ptr_type);
  						set<SPIRVariable>(var_id, ptr_type_id, StorageClassOutput, initializer);
  						entry_func.add_local_variable(var_id);
  						vars_needing_early_declaration.push_back(var_id);
  						set_name(var_id, builtin_to_glsl(builtin, StorageClassOutput));
  						set_decoration(var_id, DecorationBuiltIn, builtin);
  					}
  				}
  				else if (!is_builtin || has_active_builtin(builtin, storage))
  				{
  					bool is_composite_type = is_matrix(mbr_type) || is_array(mbr_type);
  					bool attribute_load_store =
  					    storage == StorageClassInput && get_execution_model() != ExecutionModelFragment;
  					bool storage_is_stage_io = variable_storage_requires_stage_io(storage);
  
  					// Clip/CullDistance always need to be declared as user attributes.
  					if (builtin == BuiltInClipDistance || builtin == BuiltInCullDistance)
  						is_builtin = false;
  
  					if ((!is_builtin || attribute_load_store) && storage_is_stage_io && is_composite_type)
  					{
  						add_composite_member_variable_to_interface_block(storage, ib_var_ref, ib_type, var, mbr_idx,
  						                                                 meta);
  					}
  					else
  					{
  						add_plain_member_variable_to_interface_block(storage, ib_var_ref, ib_type, var, mbr_idx, meta);
  					}
  				}
  			}
  
  			// If we're redirecting a block, we might still need to access the original block
  			// variable if we're masking some members.
  			if (masked_block && !needs_local_declaration &&
  			    (!is_builtin_variable(var) || get_execution_model() == ExecutionModelTessellationControl))
  			{
  				if (is_builtin_variable(var))
  				{
  					// Ensure correct names for the block members if we're actually going to
  					// declare gl_PerVertex.
  					for (uint32_t mbr_idx = 0; mbr_idx < uint32_t(var_type.member_types.size()); mbr_idx++)
  					{
  						set_member_name(var_type.self, mbr_idx, builtin_to_glsl(
  								BuiltIn(get_member_decoration(var_type.self, mbr_idx, DecorationBuiltIn)),
  								StorageClassOutput));
  					}
  
  					set_name(var_type.self, "gl_PerVertex");
  					set_name(var.self, "gl_out_masked");
  					stage_out_masked_builtin_type_id = var_type.self;
  				}
  				emit_local_masked_variable(var, meta.strip_array);
  			}
  		}
  	}
  	else if (get_execution_model() == ExecutionModelTessellationEvaluation && storage == StorageClassInput &&
  	         !meta.strip_array && is_builtin && (builtin == BuiltInTessLevelOuter || builtin == BuiltInTessLevelInner))
  	{
  		add_tess_level_input_to_interface_block(ib_var_ref, ib_type, var);
  	}
  	else if (var_type.basetype == SPIRType::Boolean || var_type.basetype == SPIRType::Char ||
  	         type_is_integral(var_type) || type_is_floating_point(var_type))
  	{
  		if (!is_builtin || has_active_builtin(builtin, storage))
  		{
  			bool is_composite_type = is_matrix(var_type) || is_array(var_type);
  			bool storage_is_stage_io = variable_storage_requires_stage_io(storage);
  			bool attribute_load_store = storage == StorageClassInput && get_execution_model() != ExecutionModelFragment;
  
  			// Clip/CullDistance always needs to be declared as user attributes.
  			if (builtin == BuiltInClipDistance || builtin == BuiltInCullDistance)
  				is_builtin = false;
  
  			// MSL does not allow matrices or arrays in input or output variables, so need to handle it specially.
  			if ((!is_builtin || attribute_load_store) && storage_is_stage_io && is_composite_type)
  			{
  				add_composite_variable_to_interface_block(storage, ib_var_ref, ib_type, var, meta);
  			}
  			else
  			{
  				add_plain_variable_to_interface_block(storage, ib_var_ref, ib_type, var, meta);
  			}
  		}
  	}
  }
  
  // Fix up the mapping of variables to interface member indices, which is used to compile access chains
  // for per-vertex variables in a tessellation control shader.
  void CompilerMSL::fix_up_interface_member_indices(StorageClass storage, uint32_t ib_type_id)
  {
  	// Only needed for tessellation shaders and pull-model interpolants.
  	// Need to redirect interface indices back to variables themselves.
  	// For structs, each member of the struct need a separate instance.
  	if (get_execution_model() != ExecutionModelTessellationControl &&
  	    !(get_execution_model() == ExecutionModelTessellationEvaluation && storage == StorageClassInput) &&
  	    !(get_execution_model() == ExecutionModelFragment && storage == StorageClassInput &&
  	      !pull_model_inputs.empty()))
  		return;
  
  	auto mbr_cnt = uint32_t(ir.meta[ib_type_id].members.size());
  	for (uint32_t i = 0; i < mbr_cnt; i++)
  	{
  		uint32_t var_id = get_extended_member_decoration(ib_type_id, i, SPIRVCrossDecorationInterfaceOrigID);
  		if (!var_id)
  			continue;
  		auto &var = get<SPIRVariable>(var_id);
  
  		auto &type = get_variable_element_type(var);
  
  		bool flatten_composites = variable_storage_requires_stage_io(var.storage);
  		bool is_block = has_decoration(type.self, DecorationBlock);
  
  		uint32_t mbr_idx = uint32_t(-1);
  		if (type.basetype == SPIRType::Struct && (flatten_composites || is_block))
  			mbr_idx = get_extended_member_decoration(ib_type_id, i, SPIRVCrossDecorationInterfaceMemberIndex);
  
  		if (mbr_idx != uint32_t(-1))
  		{
  			// Only set the lowest InterfaceMemberIndex for each variable member.
  			// IB struct members will be emitted in-order w.r.t. interface member index.
  			if (!has_extended_member_decoration(var_id, mbr_idx, SPIRVCrossDecorationInterfaceMemberIndex))
  				set_extended_member_decoration(var_id, mbr_idx, SPIRVCrossDecorationInterfaceMemberIndex, i);
  		}
  		else
  		{
  			// Only set the lowest InterfaceMemberIndex for each variable.
  			// IB struct members will be emitted in-order w.r.t. interface member index.
  			if (!has_extended_decoration(var_id, SPIRVCrossDecorationInterfaceMemberIndex))
  				set_extended_decoration(var_id, SPIRVCrossDecorationInterfaceMemberIndex, i);
  		}
  	}
  }
  
  // Add an interface structure for the type of storage, which is either StorageClassInput or StorageClassOutput.
  // Returns the ID of the newly added variable, or zero if no variable was added.
  uint32_t CompilerMSL::add_interface_block(StorageClass storage, bool patch)
  {
  	// Accumulate the variables that should appear in the interface struct.
  	SmallVector<SPIRVariable *> vars;
  	bool incl_builtins = storage == StorageClassOutput || is_tessellation_shader();
  	bool has_seen_barycentric = false;
  
  	InterfaceBlockMeta meta;
  
  	// Varying interfaces between stages which use "user()" attribute can be dealt with
  	// without explicit packing and unpacking of components. For any variables which link against the runtime
  	// in some way (vertex attributes, fragment output, etc), we'll need to deal with it somehow.
  	bool pack_components =
  	    (storage == StorageClassInput && get_execution_model() == ExecutionModelVertex) ||
  	    (storage == StorageClassOutput && get_execution_model() == ExecutionModelFragment) ||
  	    (storage == StorageClassOutput && get_execution_model() == ExecutionModelVertex && capture_output_to_buffer);
  
  	ir.for_each_typed_id<SPIRVariable>([&](uint32_t var_id, SPIRVariable &var) {
  		if (var.storage != storage)
  			return;
  
  		auto &type = this->get<SPIRType>(var.basetype);
  
  		bool is_builtin = is_builtin_variable(var);
  		bool is_block = has_decoration(type.self, DecorationBlock);
  
  		auto bi_type = BuiltInMax;
  		bool builtin_is_gl_in_out = false;
  		if (is_builtin && !is_block)
  		{
  			bi_type = BuiltIn(get_decoration(var_id, DecorationBuiltIn));
  			builtin_is_gl_in_out = bi_type == BuiltInPosition || bi_type == BuiltInPointSize ||
  			                       bi_type == BuiltInClipDistance || bi_type == BuiltInCullDistance;
  		}
  
  		if (is_builtin && is_block)
  			builtin_is_gl_in_out = true;
  
  		uint32_t location = get_decoration(var_id, DecorationLocation);
  
  		bool builtin_is_stage_in_out = builtin_is_gl_in_out ||
  		                               bi_type == BuiltInLayer || bi_type == BuiltInViewportIndex ||
  		                               bi_type == BuiltInBaryCoordNV || bi_type == BuiltInBaryCoordNoPerspNV ||
  		                               bi_type == BuiltInFragDepth ||
  		                               bi_type == BuiltInFragStencilRefEXT || bi_type == BuiltInSampleMask;
  
  		// These builtins are part of the stage in/out structs.
  		bool is_interface_block_builtin =
  				builtin_is_stage_in_out ||
  				(get_execution_model() == ExecutionModelTessellationEvaluation &&
  				 (bi_type == BuiltInTessLevelOuter || bi_type == BuiltInTessLevelInner));
  
  		bool is_active = interface_variable_exists_in_entry_point(var.self);
  		if (is_builtin && is_active)
  		{
  			// Only emit the builtin if it's active in this entry point. Interface variable list might lie.
  			if (is_block)
  			{
  				// If any builtin is active, the block is active.
  				uint32_t mbr_cnt = uint32_t(type.member_types.size());
  				for (uint32_t i = 0; !is_active && i < mbr_cnt; i++)
  					is_active = has_active_builtin(BuiltIn(get_member_decoration(type.self, i, DecorationBuiltIn)), storage);
  			}
  			else
  			{
  				is_active = has_active_builtin(bi_type, storage);
  			}
  		}
  
  		bool filter_patch_decoration = (has_decoration(var_id, DecorationPatch) || is_patch_block(type)) == patch;
  
  		bool hidden = is_hidden_variable(var, incl_builtins);
  
  		// ClipDistance is never hidden, we need to emulate it when used as an input.
  		if (bi_type == BuiltInClipDistance || bi_type == BuiltInCullDistance)
  			hidden = false;
  
  		// It's not enough to simply avoid marking fragment outputs if the pipeline won't
  		// accept them. We can't put them in the struct at all, or otherwise the compiler
  		// complains that the outputs weren't explicitly marked.
  		if (get_execution_model() == ExecutionModelFragment && storage == StorageClassOutput && !patch &&
  		    ((is_builtin && ((bi_type == BuiltInFragDepth && !msl_options.enable_frag_depth_builtin) ||
  		                     (bi_type == BuiltInFragStencilRefEXT && !msl_options.enable_frag_stencil_ref_builtin))) ||
  		     (!is_builtin && !(msl_options.enable_frag_output_mask & (1 << location)))))
  		{
  			hidden = true;
  			disabled_frag_outputs.push_back(var_id);
  			// If a builtin, force it to have the proper name.
  			if (is_builtin)
  				set_name(var_id, builtin_to_glsl(bi_type, StorageClassFunction));
  		}
  
  		// Barycentric inputs must be emitted in stage-in, because they can have interpolation arguments.
  		if (is_active && (bi_type == BuiltInBaryCoordNV || bi_type == BuiltInBaryCoordNoPerspNV))
  		{
  			if (has_seen_barycentric)
  				SPIRV_CROSS_THROW("Cannot declare both BaryCoordNV and BaryCoordNoPerspNV in same shader in MSL.");
  			has_seen_barycentric = true;
  			hidden = false;
  		}
  
  		if (is_active && !hidden && type.pointer && filter_patch_decoration &&
  		    (!is_builtin || is_interface_block_builtin))
  		{
  			vars.push_back(&var);
  
  			if (!is_builtin)
  			{
  				// Need to deal specially with DecorationComponent.
  				// Multiple variables can alias the same Location, and try to make sure each location is declared only once.
  				// We will swizzle data in and out to make this work.
  				// This is only relevant for vertex inputs and fragment outputs.
  				// Technically tessellation as well, but it is too complicated to support.
  				uint32_t component = get_decoration(var_id, DecorationComponent);
  				if (component != 0)
  				{
  					if (is_tessellation_shader())
  						SPIRV_CROSS_THROW("Component decoration is not supported in tessellation shaders.");
  					else if (pack_components)
  					{
  						uint32_t array_size = 1;
  						if (!type.array.empty())
  							array_size = to_array_size_literal(type);
  
  						for (uint32_t location_offset = 0; location_offset < array_size; location_offset++)
  						{
  							auto &location_meta = meta.location_meta[location + location_offset];
  							location_meta.num_components = std::max(location_meta.num_components, component + type.vecsize);
  
  							// For variables sharing location, decorations and base type must match.
  							location_meta.base_type_id = type.self;
  							location_meta.flat = has_decoration(var.self, DecorationFlat);
  							location_meta.noperspective = has_decoration(var.self, DecorationNoPerspective);
  							location_meta.centroid = has_decoration(var.self, DecorationCentroid);
  							location_meta.sample = has_decoration(var.self, DecorationSample);
  						}
  					}
  				}
  			}
  		}
  	});
  
  	// If no variables qualify, leave.
  	// For patch input in a tessellation evaluation shader, the per-vertex stage inputs
  	// are included in a special patch control point array.
  	if (vars.empty() && !(storage == StorageClassInput && patch && stage_in_var_id))
  		return 0;
  
  	// Add a new typed variable for this interface structure.
  	// The initializer expression is allocated here, but populated when the function
  	// declaraion is emitted, because it is cleared after each compilation pass.
  	uint32_t next_id = ir.increase_bound_by(3);
  	uint32_t ib_type_id = next_id++;
  	auto &ib_type = set<SPIRType>(ib_type_id);
  	ib_type.basetype = SPIRType::Struct;
  	ib_type.storage = storage;
  	set_decoration(ib_type_id, DecorationBlock);
  
  	uint32_t ib_var_id = next_id++;
  	auto &var = set<SPIRVariable>(ib_var_id, ib_type_id, storage, 0);
  	var.initializer = next_id++;
  
  	string ib_var_ref;
  	auto &entry_func = get<SPIRFunction>(ir.default_entry_point);
  	switch (storage)
  	{
  	case StorageClassInput:
  		ib_var_ref = patch ? patch_stage_in_var_name : stage_in_var_name;
  		if (get_execution_model() == ExecutionModelTessellationControl)
  		{
  			// Add a hook to populate the shared workgroup memory containing the gl_in array.
  			entry_func.fixup_hooks_in.push_back([=]() {
  				// Can't use PatchVertices, PrimitiveId, or InvocationId yet; the hooks for those may not have run yet.
  				if (msl_options.multi_patch_workgroup)
  				{
  					// n.b. builtin_invocation_id_id here is the dispatch global invocation ID,
  					// not the TC invocation ID.
  					statement("device ", to_name(ir.default_entry_point), "_", ib_var_ref, "* gl_in = &",
  					          input_buffer_var_name, "[min(", to_expression(builtin_invocation_id_id), ".x / ",
  					          get_entry_point().output_vertices,
  					          ", spvIndirectParams[1] - 1) * spvIndirectParams[0]];");
  				}
  				else
  				{
  					// It's safe to use InvocationId here because it's directly mapped to a
  					// Metal builtin, and therefore doesn't need a hook.
  					statement("if (", to_expression(builtin_invocation_id_id), " < spvIndirectParams[0])");
  					statement("    ", input_wg_var_name, "[", to_expression(builtin_invocation_id_id),
  					          "] = ", ib_var_ref, ";");
  					statement("threadgroup_barrier(mem_flags::mem_threadgroup);");
  					statement("if (", to_expression(builtin_invocation_id_id),
  					          " >= ", get_entry_point().output_vertices, ")");
  					statement("    return;");
  				}
  			});
  		}
  		break;
  
  	case StorageClassOutput:
  	{
  		ib_var_ref = patch ? patch_stage_out_var_name : stage_out_var_name;
  
  		// Add the output interface struct as a local variable to the entry function.
  		// If the entry point should return the output struct, set the entry function
  		// to return the output interface struct, otherwise to return nothing.
  		// Indicate the output var requires early initialization.
  		bool ep_should_return_output = !get_is_rasterization_disabled();
  		uint32_t rtn_id = ep_should_return_output ? ib_var_id : 0;
  		if (!capture_output_to_buffer)
  		{
  			entry_func.add_local_variable(ib_var_id);
  			for (auto &blk_id : entry_func.blocks)
  			{
  				auto &blk = get<SPIRBlock>(blk_id);
  				if (blk.terminator == SPIRBlock::Return)
  					blk.return_value = rtn_id;
  			}
  			vars_needing_early_declaration.push_back(ib_var_id);
  		}
  		else
  		{
  			switch (get_execution_model())
  			{
  			case ExecutionModelVertex:
  			case ExecutionModelTessellationEvaluation:
  				// Instead of declaring a struct variable to hold the output and then
  				// copying that to the output buffer, we'll declare the output variable
  				// as a reference to the final output element in the buffer. Then we can
  				// avoid the extra copy.
  				entry_func.fixup_hooks_in.push_back([=]() {
  					if (stage_out_var_id)
  					{
  						// The first member of the indirect buffer is always the number of vertices
  						// to draw.
  						// We zero-base the InstanceID & VertexID variables for HLSL emulation elsewhere, so don't do it twice
  						if (get_execution_model() == ExecutionModelVertex && msl_options.vertex_for_tessellation)
  						{
  							statement("device ", to_name(ir.default_entry_point), "_", ib_var_ref, "& ", ib_var_ref,
  							          " = ", output_buffer_var_name, "[", to_expression(builtin_invocation_id_id),
  							          ".y * ", to_expression(builtin_stage_input_size_id), ".x + ",
  							          to_expression(builtin_invocation_id_id), ".x];");
  						}
  						else if (msl_options.enable_base_index_zero)
  						{
  							statement("device ", to_name(ir.default_entry_point), "_", ib_var_ref, "& ", ib_var_ref,
  							          " = ", output_buffer_var_name, "[", to_expression(builtin_instance_idx_id),
  							          " * spvIndirectParams[0] + ", to_expression(builtin_vertex_idx_id), "];");
  						}
  						else
  						{
  							statement("device ", to_name(ir.default_entry_point), "_", ib_var_ref, "& ", ib_var_ref,
  							          " = ", output_buffer_var_name, "[(", to_expression(builtin_instance_idx_id),
  							          " - ", to_expression(builtin_base_instance_id), ") * spvIndirectParams[0] + ",
  							          to_expression(builtin_vertex_idx_id), " - ",
  							          to_expression(builtin_base_vertex_id), "];");
  						}
  					}
  				});
  				break;
  			case ExecutionModelTessellationControl:
  				if (msl_options.multi_patch_workgroup)
  				{
  					// We cannot use PrimitiveId here, because the hook may not have run yet.
  					if (patch)
  					{
  						entry_func.fixup_hooks_in.push_back([=]() {
  							statement("device ", to_name(ir.default_entry_point), "_", ib_var_ref, "& ", ib_var_ref,
  							          " = ", patch_output_buffer_var_name, "[", to_expression(builtin_invocation_id_id),
  							          ".x / ", get_entry_point().output_vertices, "];");
  						});
  					}
  					else
  					{
  						entry_func.fixup_hooks_in.push_back([=]() {
  							statement("device ", to_name(ir.default_entry_point), "_", ib_var_ref, "* gl_out = &",
  							          output_buffer_var_name, "[", to_expression(builtin_invocation_id_id), ".x - ",
  							          to_expression(builtin_invocation_id_id), ".x % ",
  							          get_entry_point().output_vertices, "];");
  						});
  					}
  				}
  				else
  				{
  					if (patch)
  					{
  						entry_func.fixup_hooks_in.push_back([=]() {
  							statement("device ", to_name(ir.default_entry_point), "_", ib_var_ref, "& ", ib_var_ref,
  							          " = ", patch_output_buffer_var_name, "[", to_expression(builtin_primitive_id_id),
  							          "];");
  						});
  					}
  					else
  					{
  						entry_func.fixup_hooks_in.push_back([=]() {
  							statement("device ", to_name(ir.default_entry_point), "_", ib_var_ref, "* gl_out = &",
  							          output_buffer_var_name, "[", to_expression(builtin_primitive_id_id), " * ",
  							          get_entry_point().output_vertices, "];");
  						});
  					}
  				}
  				break;
  			default:
  				break;
  			}
  		}
  		break;
  	}
  
  	default:
  		break;
  	}
  
  	set_name(ib_type_id, to_name(ir.default_entry_point) + "_" + ib_var_ref);
  	set_name(ib_var_id, ib_var_ref);
  
  	for (auto *p_var : vars)
  	{
  		bool strip_array =
  		    (get_execution_model() == ExecutionModelTessellationControl ||
  		     (get_execution_model() == ExecutionModelTessellationEvaluation && storage == StorageClassInput)) &&
  		    !patch;
  
  		// Fixing up flattened stores in TESC is impossible since the memory is group shared either via
  		// device (not masked) or threadgroup (masked) storage classes and it's race condition city.
  		meta.strip_array = strip_array;
  		meta.allow_local_declaration = !strip_array && !(get_execution_model() == ExecutionModelTessellationControl &&
  		                                                 storage == StorageClassOutput);
  		add_variable_to_interface_block(storage, ib_var_ref, ib_type, *p_var, meta);
  	}
  
  	if (get_execution_model() == ExecutionModelTessellationControl && msl_options.multi_patch_workgroup &&
  	    storage == StorageClassInput)
  	{
  		// For tessellation control inputs, add all outputs from the vertex shader to ensure
  		// the struct containing them is the correct size and layout.
  		for (auto &input : inputs_by_location)
  		{
  			if (location_inputs_in_use.count(input.first) != 0)
  				continue;
  
  			// Create a fake variable to put at the location.
  			uint32_t offset = ir.increase_bound_by(4);
  			uint32_t type_id = offset;
  			uint32_t array_type_id = offset + 1;
  			uint32_t ptr_type_id = offset + 2;
  			uint32_t var_id = offset + 3;
  
  			SPIRType type;
  			switch (input.second.format)
  			{
  			case MSL_SHADER_INPUT_FORMAT_UINT16:
  			case MSL_SHADER_INPUT_FORMAT_ANY16:
  				type.basetype = SPIRType::UShort;
  				type.width = 16;
  				break;
  			case MSL_SHADER_INPUT_FORMAT_ANY32:
  			default:
  				type.basetype = SPIRType::UInt;
  				type.width = 32;
  				break;
  			}
  			type.vecsize = input.second.vecsize;
  			set<SPIRType>(type_id, type);
  
  			type.array.push_back(0);
  			type.array_size_literal.push_back(true);
  			type.parent_type = type_id;
  			set<SPIRType>(array_type_id, type);
  
  			type.pointer = true;
  			type.pointer_depth++;
  			type.parent_type = array_type_id;
  			type.storage = storage;
  			auto &ptr_type = set<SPIRType>(ptr_type_id, type);
  			ptr_type.self = array_type_id;
  
  			auto &fake_var = set<SPIRVariable>(var_id, ptr_type_id, storage);
  			set_decoration(var_id, DecorationLocation, input.first);
  			meta.strip_array = true;
  			meta.allow_local_declaration = false;
  			add_variable_to_interface_block(storage, ib_var_ref, ib_type, fake_var, meta);
  		}
  	}
  
  	// When multiple variables need to access same location,
  	// unroll locations one by one and we will flatten output or input as necessary.
  	for (auto &loc : meta.location_meta)
  	{
  		uint32_t location = loc.first;
  		auto &location_meta = loc.second;
  
  		uint32_t ib_mbr_idx = uint32_t(ib_type.member_types.size());
  		uint32_t type_id = build_extended_vector_type(location_meta.base_type_id, location_meta.num_components);
  		ib_type.member_types.push_back(type_id);
  
  		set_member_name(ib_type.self, ib_mbr_idx, join("m_location_", location));
  		set_member_decoration(ib_type.self, ib_mbr_idx, DecorationLocation, location);
  		mark_location_as_used_by_shader(location, get<SPIRType>(type_id), storage);
  
  		if (location_meta.flat)
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationFlat);
  		if (location_meta.noperspective)
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationNoPerspective);
  		if (location_meta.centroid)
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationCentroid);
  		if (location_meta.sample)
  			set_member_decoration(ib_type.self, ib_mbr_idx, DecorationSample);
  	}
  
  	// Sort the members of the structure by their locations.
  	MemberSorter member_sorter(ib_type, ir.meta[ib_type_id], MemberSorter::LocationThenBuiltInType);
  	member_sorter.sort();
  
  	// The member indices were saved to the original variables, but after the members
  	// were sorted, those indices are now likely incorrect. Fix those up now.
  	fix_up_interface_member_indices(storage, ib_type_id);
  
  	// For patch inputs, add one more member, holding the array of control point data.
  	if (get_execution_model() == ExecutionModelTessellationEvaluation && storage == StorageClassInput && patch &&
  	    stage_in_var_id)
  	{
  		uint32_t pcp_type_id = ir.increase_bound_by(1);
  		auto &pcp_type = set<SPIRType>(pcp_type_id, ib_type);
  		pcp_type.basetype = SPIRType::ControlPointArray;
  		pcp_type.parent_type = pcp_type.type_alias = get_stage_in_struct_type().self;
  		pcp_type.storage = storage;
  		ir.meta[pcp_type_id] = ir.meta[ib_type.self];
  		uint32_t mbr_idx = uint32_t(ib_type.member_types.size());
  		ib_type.member_types.push_back(pcp_type_id);
  		set_member_name(ib_type.self, mbr_idx, "gl_in");
  	}
  
  	return ib_var_id;
  }
  
  uint32_t CompilerMSL::add_interface_block_pointer(uint32_t ib_var_id, StorageClass storage)
  {
  	if (!ib_var_id)
  		return 0;
  
  	uint32_t ib_ptr_var_id;
  	uint32_t next_id = ir.increase_bound_by(3);
  	auto &ib_type = expression_type(ib_var_id);
  	if (get_execution_model() == ExecutionModelTessellationControl)
  	{
  		// Tessellation control per-vertex I/O is presented as an array, so we must
  		// do the same with our struct here.
  		uint32_t ib_ptr_type_id = next_id++;
  		auto &ib_ptr_type = set<SPIRType>(ib_ptr_type_id, ib_type);
  		ib_ptr_type.parent_type = ib_ptr_type.type_alias = ib_type.self;
  		ib_ptr_type.pointer = true;
  		ib_ptr_type.pointer_depth++;
  		ib_ptr_type.storage =
  		    storage == StorageClassInput ?
  		        (msl_options.multi_patch_workgroup ? StorageClassStorageBuffer : StorageClassWorkgroup) :
  		        StorageClassStorageBuffer;
  		ir.meta[ib_ptr_type_id] = ir.meta[ib_type.self];
  		// To ensure that get_variable_data_type() doesn't strip off the pointer,
  		// which we need, use another pointer.
  		uint32_t ib_ptr_ptr_type_id = next_id++;
  		auto &ib_ptr_ptr_type = set<SPIRType>(ib_ptr_ptr_type_id, ib_ptr_type);
  		ib_ptr_ptr_type.parent_type = ib_ptr_type_id;
  		ib_ptr_ptr_type.type_alias = ib_type.self;
  		ib_ptr_ptr_type.storage = StorageClassFunction;
  		ir.meta[ib_ptr_ptr_type_id] = ir.meta[ib_type.self];
  
  		ib_ptr_var_id = next_id;
  		set<SPIRVariable>(ib_ptr_var_id, ib_ptr_ptr_type_id, StorageClassFunction, 0);
  		set_name(ib_ptr_var_id, storage == StorageClassInput ? "gl_in" : "gl_out");
  	}
  	else
  	{
  		// Tessellation evaluation per-vertex inputs are also presented as arrays.
  		// But, in Metal, this array uses a very special type, 'patch_control_point<T>',
  		// which is a container that can be used to access the control point data.
  		// To represent this, a special 'ControlPointArray' type has been added to the
  		// SPIRV-Cross type system. It should only be generated by and seen in the MSL
  		// backend (i.e. this one).
  		uint32_t pcp_type_id = next_id++;
  		auto &pcp_type = set<SPIRType>(pcp_type_id, ib_type);
  		pcp_type.basetype = SPIRType::ControlPointArray;
  		pcp_type.parent_type = pcp_type.type_alias = ib_type.self;
  		pcp_type.storage = storage;
  		ir.meta[pcp_type_id] = ir.meta[ib_type.self];
  
  		ib_ptr_var_id = next_id;
  		set<SPIRVariable>(ib_ptr_var_id, pcp_type_id, storage, 0);
  		set_name(ib_ptr_var_id, "gl_in");
  		ir.meta[ib_ptr_var_id].decoration.qualified_alias = join(patch_stage_in_var_name, ".gl_in");
  	}
  	return ib_ptr_var_id;
  }
  
  // Ensure that the type is compatible with the builtin.
  // If it is, simply return the given type ID.
  // Otherwise, create a new type, and return it's ID.
  uint32_t CompilerMSL::ensure_correct_builtin_type(uint32_t type_id, BuiltIn builtin)
  {
  	auto &type = get<SPIRType>(type_id);
  
  	if ((builtin == BuiltInSampleMask && is_array(type)) ||
  	    ((builtin == BuiltInLayer || builtin == BuiltInViewportIndex || builtin == BuiltInFragStencilRefEXT) &&
  	     type.basetype != SPIRType::UInt))
  	{
  		uint32_t next_id = ir.increase_bound_by(type.pointer ? 2 : 1);
  		uint32_t base_type_id = next_id++;
  		auto &base_type = set<SPIRType>(base_type_id);
  		base_type.basetype = SPIRType::UInt;
  		base_type.width = 32;
  
  		if (!type.pointer)
  			return base_type_id;
  
  		uint32_t ptr_type_id = next_id++;
  		auto &ptr_type = set<SPIRType>(ptr_type_id);
  		ptr_type = base_type;
  		ptr_type.pointer = true;
  		ptr_type.pointer_depth++;
  		ptr_type.storage = type.storage;
  		ptr_type.parent_type = base_type_id;
  		return ptr_type_id;
  	}
  
  	return type_id;
  }
  
  // Ensure that the type is compatible with the shader input.
  // If it is, simply return the given type ID.
  // Otherwise, create a new type, and return its ID.
  uint32_t CompilerMSL::ensure_correct_input_type(uint32_t type_id, uint32_t location, uint32_t num_components, bool strip_array)
  {
  	auto &type = get<SPIRType>(type_id);
  
  	uint32_t max_array_dimensions = strip_array ? 1 : 0;
  
  	// Struct and array types must match exactly.
  	if (type.basetype == SPIRType::Struct || type.array.size() > max_array_dimensions)
  		return type_id;
  
  	auto p_va = inputs_by_location.find(location);
  	if (p_va == end(inputs_by_location))
  	{
  		if (num_components > type.vecsize)
  			return build_extended_vector_type(type_id, num_components);
  		else
  			return type_id;
  	}
  
  	if (num_components == 0)
  		num_components = p_va->second.vecsize;
  
  	switch (p_va->second.format)
  	{
  	case MSL_SHADER_INPUT_FORMAT_UINT8:
  	{
  		switch (type.basetype)
  		{
  		case SPIRType::UByte:
  		case SPIRType::UShort:
  		case SPIRType::UInt:
  			if (num_components > type.vecsize)
  				return build_extended_vector_type(type_id, num_components);
  			else
  				return type_id;
  
  		case SPIRType::Short:
  			return build_extended_vector_type(type_id, num_components > type.vecsize ? num_components : type.vecsize,
  			                                  SPIRType::UShort);
  		case SPIRType::Int:
  			return build_extended_vector_type(type_id, num_components > type.vecsize ? num_components : type.vecsize,
  			                                  SPIRType::UInt);
  
  		default:
  			SPIRV_CROSS_THROW("Vertex attribute type mismatch between host and shader");
  		}
  	}
  
  	case MSL_SHADER_INPUT_FORMAT_UINT16:
  	{
  		switch (type.basetype)
  		{
  		case SPIRType::UShort:
  		case SPIRType::UInt:
  			if (num_components > type.vecsize)
  				return build_extended_vector_type(type_id, num_components);
  			else
  				return type_id;
  
  		case SPIRType::Int:
  			return build_extended_vector_type(type_id, num_components > type.vecsize ? num_components : type.vecsize,
  			                                  SPIRType::UInt);
  
  		default:
  			SPIRV_CROSS_THROW("Vertex attribute type mismatch between host and shader");
  		}
  	}
  
  	default:
  		if (num_components > type.vecsize)
  			type_id = build_extended_vector_type(type_id, num_components);
  		break;
  	}
  
  	return type_id;
  }
  
  void CompilerMSL::mark_struct_members_packed(const SPIRType &type)
  {
  	set_extended_decoration(type.self, SPIRVCrossDecorationPhysicalTypePacked);
  
  	// Problem case! Struct needs to be placed at an awkward alignment.
  	// Mark every member of the child struct as packed.
  	uint32_t mbr_cnt = uint32_t(type.member_types.size());
  	for (uint32_t i = 0; i < mbr_cnt; i++)
  	{
  		auto &mbr_type = get<SPIRType>(type.member_types[i]);
  		if (mbr_type.basetype == SPIRType::Struct)
  		{
  			// Recursively mark structs as packed.
  			auto *struct_type = &mbr_type;
  			while (!struct_type->array.empty())
  				struct_type = &get<SPIRType>(struct_type->parent_type);
  			mark_struct_members_packed(*struct_type);
  		}
  		else if (!is_scalar(mbr_type))
  			set_extended_member_decoration(type.self, i, SPIRVCrossDecorationPhysicalTypePacked);
  	}
  }
  
  void CompilerMSL::mark_scalar_layout_structs(const SPIRType &type)
  {
  	uint32_t mbr_cnt = uint32_t(type.member_types.size());
  	for (uint32_t i = 0; i < mbr_cnt; i++)
  	{
  		auto &mbr_type = get<SPIRType>(type.member_types[i]);
  		if (mbr_type.basetype == SPIRType::Struct)
  		{
  			auto *struct_type = &mbr_type;
  			while (!struct_type->array.empty())
  				struct_type = &get<SPIRType>(struct_type->parent_type);
  
  			if (has_extended_decoration(struct_type->self, SPIRVCrossDecorationPhysicalTypePacked))
  				continue;
  
  			uint32_t msl_alignment = get_declared_struct_member_alignment_msl(type, i);
  			uint32_t msl_size = get_declared_struct_member_size_msl(type, i);
  			uint32_t spirv_offset = type_struct_member_offset(type, i);
  			uint32_t spirv_offset_next;
  			if (i + 1 < mbr_cnt)
  				spirv_offset_next = type_struct_member_offset(type, i + 1);
  			else
  				spirv_offset_next = spirv_offset + msl_size;
  
  			// Both are complicated cases. In scalar layout, a struct of float3 might just consume 12 bytes,
  			// and the next member will be placed at offset 12.
  			bool struct_is_misaligned = (spirv_offset % msl_alignment) != 0;
  			bool struct_is_too_large = spirv_offset + msl_size > spirv_offset_next;
  			uint32_t array_stride = 0;
  			bool struct_needs_explicit_padding = false;
  
  			// Verify that if a struct is used as an array that ArrayStride matches the effective size of the struct.
  			if (!mbr_type.array.empty())
  			{
  				array_stride = type_struct_member_array_stride(type, i);
  				uint32_t dimensions = uint32_t(mbr_type.array.size() - 1);
  				for (uint32_t dim = 0; dim < dimensions; dim++)
  				{
  					uint32_t array_size = to_array_size_literal(mbr_type, dim);
  					array_stride /= max(array_size, 1u);
  				}
  
  				// Set expected struct size based on ArrayStride.
  				struct_needs_explicit_padding = true;
  
  				// If struct size is larger than array stride, we might be able to fit, if we tightly pack.
  				if (get_declared_struct_size_msl(*struct_type) > array_stride)
  					struct_is_too_large = true;
  			}
  
  			if (struct_is_misaligned || struct_is_too_large)
  				mark_struct_members_packed(*struct_type);
  			mark_scalar_layout_structs(*struct_type);
  
  			if (struct_needs_explicit_padding)
  			{
  				msl_size = get_declared_struct_size_msl(*struct_type, true, true);
  				if (array_stride < msl_size)
  				{
  					SPIRV_CROSS_THROW("Cannot express an array stride smaller than size of struct type.");
  				}
  				else
  				{
  					if (has_extended_decoration(struct_type->self, SPIRVCrossDecorationPaddingTarget))
  					{
  						if (array_stride !=
  						    get_extended_decoration(struct_type->self, SPIRVCrossDecorationPaddingTarget))
  							SPIRV_CROSS_THROW(
  							    "A struct is used with different array strides. Cannot express this in MSL.");
  					}
  					else
  						set_extended_decoration(struct_type->self, SPIRVCrossDecorationPaddingTarget, array_stride);
  				}
  			}
  		}
  	}
  }
  
  // Sort the members of the struct type by offset, and pack and then pad members where needed
  // to align MSL members with SPIR-V offsets. The struct members are iterated twice. Packing
  // occurs first, followed by padding, because packing a member reduces both its size and its
  // natural alignment, possibly requiring a padding member to be added ahead of it.
  void CompilerMSL::align_struct(SPIRType &ib_type, unordered_set<uint32_t> &aligned_structs)
  {
  	// We align structs recursively, so stop any redundant work.
  	ID &ib_type_id = ib_type.self;
  	if (aligned_structs.count(ib_type_id))
  		return;
  	aligned_structs.insert(ib_type_id);
  
  	// Sort the members of the interface structure by their offset.
  	// They should already be sorted per SPIR-V spec anyway.
  	MemberSorter member_sorter(ib_type, ir.meta[ib_type_id], MemberSorter::Offset);
  	member_sorter.sort();
  
  	auto mbr_cnt = uint32_t(ib_type.member_types.size());
  
  	for (uint32_t mbr_idx = 0; mbr_idx < mbr_cnt; mbr_idx++)
  	{
  		// Pack any dependent struct types before we pack a parent struct.
  		auto &mbr_type = get<SPIRType>(ib_type.member_types[mbr_idx]);
  		if (mbr_type.basetype == SPIRType::Struct)
  			align_struct(mbr_type, aligned_structs);
  	}
  
  	// Test the alignment of each member, and if a member should be closer to the previous
  	// member than the default spacing expects, it is likely that the previous member is in
  	// a packed format. If so, and the previous member is packable, pack it.
  	// For example ... this applies to any 3-element vector that is followed by a scalar.
  	uint32_t msl_offset = 0;
  	for (uint32_t mbr_idx = 0; mbr_idx < mbr_cnt; mbr_idx++)
  	{
  		// This checks the member in isolation, if the member needs some kind of type remapping to conform to SPIR-V
  		// offsets, array strides and matrix strides.
  		ensure_member_packing_rules_msl(ib_type, mbr_idx);
  
  		// Align current offset to the current member's default alignment. If the member was packed, it will observe
  		// the updated alignment here.
  		uint32_t msl_align_mask = get_declared_struct_member_alignment_msl(ib_type, mbr_idx) - 1;
  		uint32_t aligned_msl_offset = (msl_offset + msl_align_mask) & ~msl_align_mask;
  
  		// Fetch the member offset as declared in the SPIRV.
  		uint32_t spirv_mbr_offset = get_member_decoration(ib_type_id, mbr_idx, DecorationOffset);
  		if (spirv_mbr_offset > aligned_msl_offset)
  		{
  			// Since MSL and SPIR-V have slightly different struct member alignment and
  			// size rules, we'll pad to standard C-packing rules with a char[] array. If the member is farther
  			// away than C-packing, expects, add an inert padding member before the the member.
  			uint32_t padding_bytes = spirv_mbr_offset - aligned_msl_offset;
  			set_extended_member_decoration(ib_type_id, mbr_idx, SPIRVCrossDecorationPaddingTarget, padding_bytes);
  
  			// Re-align as a sanity check that aligning post-padding matches up.
  			msl_offset += padding_bytes;
  			aligned_msl_offset = (msl_offset + msl_align_mask) & ~msl_align_mask;
  		}
  		else if (spirv_mbr_offset < aligned_msl_offset)
  		{
  			// This should not happen, but deal with unexpected scenarios.
  			// It *might* happen if a sub-struct has a larger alignment requirement in MSL than SPIR-V.
  			SPIRV_CROSS_THROW("Cannot represent buffer block correctly in MSL.");
  		}
  
  		assert(aligned_msl_offset == spirv_mbr_offset);
  
  		// Increment the current offset to be positioned immediately after the current member.
  		// Don't do this for the last member since it can be unsized, and it is not relevant for padding purposes here.
  		if (mbr_idx + 1 < mbr_cnt)
  			msl_offset = aligned_msl_offset + get_declared_struct_member_size_msl(ib_type, mbr_idx);
  	}
  }
  
  bool CompilerMSL::validate_member_packing_rules_msl(const SPIRType &type, uint32_t index) const
  {
  	auto &mbr_type = get<SPIRType>(type.member_types[index]);
  	uint32_t spirv_offset = get_member_decoration(type.self, index, DecorationOffset);
  
  	if (index + 1 < type.member_types.size())
  	{
  		// First, we will check offsets. If SPIR-V offset + MSL size > SPIR-V offset of next member,
  		// we *must* perform some kind of remapping, no way getting around it.
  		// We can always pad after this member if necessary, so that case is fine.
  		uint32_t spirv_offset_next = get_member_decoration(type.self, index + 1, DecorationOffset);
  		assert(spirv_offset_next >= spirv_offset);
  		uint32_t maximum_size = spirv_offset_next - spirv_offset;
  		uint32_t msl_mbr_size = get_declared_struct_member_size_msl(type, index);
  		if (msl_mbr_size > maximum_size)
  			return false;
  	}
  
  	if (!mbr_type.array.empty())
  	{
  		// If we have an array type, array stride must match exactly with SPIR-V.
  
  		// An exception to this requirement is if we have one array element.
  		// This comes from DX scalar layout workaround.
  		// If app tries to be cheeky and access the member out of bounds, this will not work, but this is the best we can do.
  		// In OpAccessChain with logical memory models, access chains must be in-bounds in SPIR-V specification.
  		bool relax_array_stride = mbr_type.array.back() == 1 && mbr_type.array_size_literal.back();
  
  		if (!relax_array_stride)
  		{
  			uint32_t spirv_array_stride = type_struct_member_array_stride(type, index);
  			uint32_t msl_array_stride = get_declared_struct_member_array_stride_msl(type, index);
  			if (spirv_array_stride != msl_array_stride)
  				return false;
  		}
  	}
  
  	if (is_matrix(mbr_type))
  	{
  		// Need to check MatrixStride as well.
  		uint32_t spirv_matrix_stride = type_struct_member_matrix_stride(type, index);
  		uint32_t msl_matrix_stride = get_declared_struct_member_matrix_stride_msl(type, index);
  		if (spirv_matrix_stride != msl_matrix_stride)
  			return false;
  	}
  
  	// Now, we check alignment.
  	uint32_t msl_alignment = get_declared_struct_member_alignment_msl(type, index);
  	if ((spirv_offset % msl_alignment) != 0)
  		return false;
  
  	// We're in the clear.
  	return true;
  }
  
  // Here we need to verify that the member type we declare conforms to Offset, ArrayStride or MatrixStride restrictions.
  // If there is a mismatch, we need to emit remapped types, either normal types, or "packed_X" types.
  // In odd cases we need to emit packed and remapped types, for e.g. weird matrices or arrays with weird array strides.
  void CompilerMSL::ensure_member_packing_rules_msl(SPIRType &ib_type, uint32_t index)
  {
  	if (validate_member_packing_rules_msl(ib_type, index))
  		return;
  
  	// We failed validation.
  	// This case will be nightmare-ish to deal with. This could possibly happen if struct alignment does not quite
  	// match up with what we want. Scalar block layout comes to mind here where we might have to work around the rule
  	// that struct alignment == max alignment of all members and struct size depends on this alignment.
  	auto &mbr_type = get<SPIRType>(ib_type.member_types[index]);
  	if (mbr_type.basetype == SPIRType::Struct)
  		SPIRV_CROSS_THROW("Cannot perform any repacking for structs when it is used as a member of another struct.");
  
  	// Perform remapping here.
  	// There is nothing to be gained by using packed scalars, so don't attempt it.
  	if (!is_scalar(ib_type))
  		set_extended_member_decoration(ib_type.self, index, SPIRVCrossDecorationPhysicalTypePacked);
  
  	// Try validating again, now with packed.
  	if (validate_member_packing_rules_msl(ib_type, index))
  		return;
  
  	// We're in deep trouble, and we need to create a new PhysicalType which matches up with what we expect.
  	// A lot of work goes here ...
  	// We will need remapping on Load and Store to translate the types between Logical and Physical.
  
  	// First, we check if we have small vector std140 array.
  	// We detect this if we have an array of vectors, and array stride is greater than number of elements.
  	if (!mbr_type.array.empty() && !is_matrix(mbr_type))
  	{
  		uint32_t array_stride = type_struct_member_array_stride(ib_type, index);
  
  		// Hack off array-of-arrays until we find the array stride per element we must have to make it work.
  		uint32_t dimensions = uint32_t(mbr_type.array.size() - 1);
  		for (uint32_t dim = 0; dim < dimensions; dim++)
  			array_stride /= max(to_array_size_literal(mbr_type, dim), 1u);
  
  		uint32_t elems_per_stride = array_stride / (mbr_type.width / 8);
  
  		if (elems_per_stride == 3)
  			SPIRV_CROSS_THROW("Cannot use ArrayStride of 3 elements in remapping scenarios.");
  		else if (elems_per_stride > 4)
  			SPIRV_CROSS_THROW("Cannot represent vectors with more than 4 elements in MSL.");
  
  		auto physical_type = mbr_type;
  		physical_type.vecsize = elems_per_stride;
  		physical_type.parent_type = 0;
  		uint32_t type_id = ir.increase_bound_by(1);
  		set<SPIRType>(type_id, physical_type);
  		set_extended_member_decoration(ib_type.self, index, SPIRVCrossDecorationPhysicalTypeID, type_id);
  		set_decoration(type_id, DecorationArrayStride, array_stride);
  
  		// Remove packed_ for vectors of size 1, 2 and 4.
  		if (has_extended_decoration(ib_type.self, SPIRVCrossDecorationPhysicalTypePacked))
  			SPIRV_CROSS_THROW("Unable to remove packed decoration as entire struct must be fully packed. Do not mix "
  			                  "scalar and std140 layout rules.");
  		else
  			unset_extended_member_decoration(ib_type.self, index, SPIRVCrossDecorationPhysicalTypePacked);
  	}
  	else if (is_matrix(mbr_type))
  	{
  		// MatrixStride might be std140-esque.
  		uint32_t matrix_stride = type_struct_member_matrix_stride(ib_type, index);
  
  		uint32_t elems_per_stride = matrix_stride / (mbr_type.width / 8);
  
  		if (elems_per_stride == 3)
  			SPIRV_CROSS_THROW("Cannot use ArrayStride of 3 elements in remapping scenarios.");
  		else if (elems_per_stride > 4)
  			SPIRV_CROSS_THROW("Cannot represent vectors with more than 4 elements in MSL.");
  
  		bool row_major = has_member_decoration(ib_type.self, index, DecorationRowMajor);
  
  		auto physical_type = mbr_type;
  		physical_type.parent_type = 0;
  		if (row_major)
  			physical_type.columns = elems_per_stride;
  		else
  			physical_type.vecsize = elems_per_stride;
  		uint32_t type_id = ir.increase_bound_by(1);
  		set<SPIRType>(type_id, physical_type);
  		set_extended_member_decoration(ib_type.self, index, SPIRVCrossDecorationPhysicalTypeID, type_id);
  
  		// Remove packed_ for vectors of size 1, 2 and 4.
  		if (has_extended_decoration(ib_type.self, SPIRVCrossDecorationPhysicalTypePacked))
  			SPIRV_CROSS_THROW("Unable to remove packed decoration as entire struct must be fully packed. Do not mix "
  			                  "scalar and std140 layout rules.");
  		else
  			unset_extended_member_decoration(ib_type.self, index, SPIRVCrossDecorationPhysicalTypePacked);
  	}
  	else
  		SPIRV_CROSS_THROW("Found a buffer packing case which we cannot represent in MSL.");
  
  	// Try validating again, now with physical type remapping.
  	if (validate_member_packing_rules_msl(ib_type, index))
  		return;
  
  	// We might have a particular odd scalar layout case where the last element of an array
  	// does not take up as much space as the ArrayStride or MatrixStride. This can happen with DX cbuffers.
  	// The "proper" workaround for this is extremely painful and essentially impossible in the edge case of float3[],
  	// so we hack around it by declaring the offending array or matrix with one less array size/col/row,
  	// and rely on padding to get the correct value. We will technically access arrays out of bounds into the padding region,
  	// but it should spill over gracefully without too much trouble. We rely on behavior like this for unsized arrays anyways.
  
  	// E.g. we might observe a physical layout of:
  	// { float2 a[2]; float b; } in cbuffer layout where ArrayStride of a is 16, but offset of b is 24, packed right after a[1] ...
  	uint32_t type_id = get_extended_member_decoration(ib_type.self, index, SPIRVCrossDecorationPhysicalTypeID);
  	auto &type = get<SPIRType>(type_id);
  
  	// Modify the physical type in-place. This is safe since each physical type workaround is a copy.
  	if (is_array(type))
  	{
  		if (type.array.back() > 1)
  		{
  			if (!type.array_size_literal.back())
  				SPIRV_CROSS_THROW("Cannot apply scalar layout workaround with spec constant array size.");
  			type.array.back() -= 1;
  		}
  		else
  		{
  			// We have an array of size 1, so we cannot decrement that. Our only option now is to
  			// force a packed layout instead, and drop the physical type remap since ArrayStride is meaningless now.
  			unset_extended_member_decoration(ib_type.self, index, SPIRVCrossDecorationPhysicalTypeID);
  			set_extended_member_decoration(ib_type.self, index, SPIRVCrossDecorationPhysicalTypePacked);
  		}
  	}
  	else if (is_matrix(type))
  	{
  		bool row_major = has_member_decoration(ib_type.self, index, DecorationRowMajor);
  		if (!row_major)
  		{
  			// Slice off one column. If we only have 2 columns, this might turn the matrix into a vector with one array element instead.
  			if (type.columns > 2)
  			{
  				type.columns--;
  			}
  			else if (type.columns == 2)
  			{
  				type.columns = 1;
  				assert(type.array.empty());
  				type.array.push_back(1);
  				type.array_size_literal.push_back(true);
  			}
  		}
  		else
  		{
  			// Slice off one row. If we only have 2 rows, this might turn the matrix into a vector with one array element instead.
  			if (type.vecsize > 2)
  			{
  				type.vecsize--;
  			}
  			else if (type.vecsize == 2)
  			{
  				type.vecsize = type.columns;
  				type.columns = 1;
  				assert(type.array.empty());
  				type.array.push_back(1);
  				type.array_size_literal.push_back(true);
  			}
  		}
  	}
  
  	// This better validate now, or we must fail gracefully.
  	if (!validate_member_packing_rules_msl(ib_type, index))
  		SPIRV_CROSS_THROW("Found a buffer packing case which we cannot represent in MSL.");
  }
  
  void CompilerMSL::emit_store_statement(uint32_t lhs_expression, uint32_t rhs_expression)
  {
  	auto &type = expression_type(rhs_expression);
  
  	bool lhs_remapped_type = has_extended_decoration(lhs_expression, SPIRVCrossDecorationPhysicalTypeID);
  	bool lhs_packed_type = has_extended_decoration(lhs_expression, SPIRVCrossDecorationPhysicalTypePacked);
  	auto *lhs_e = maybe_get<SPIRExpression>(lhs_expression);
  	auto *rhs_e = maybe_get<SPIRExpression>(rhs_expression);
  
  	bool transpose = lhs_e && lhs_e->need_transpose;
  
  	// No physical type remapping, and no packed type, so can just emit a store directly.
  	if (!lhs_remapped_type && !lhs_packed_type)
  	{
  		// We might not be dealing with remapped physical types or packed types,
  		// but we might be doing a clean store to a row-major matrix.
  		// In this case, we just flip transpose states, and emit the store, a transpose must be in the RHS expression, if any.
  		if (is_matrix(type) && lhs_e && lhs_e->need_transpose)
  		{
  			lhs_e->need_transpose = false;
  
  			if (rhs_e && rhs_e->need_transpose)
  			{
  				// Direct copy, but might need to unpack RHS.
  				// Skip the transpose, as we will transpose when writing to LHS and transpose(transpose(T)) == T.
  				rhs_e->need_transpose = false;
  				statement(to_expression(lhs_expression), " = ", to_unpacked_row_major_matrix_expression(rhs_expression),
  				          ";");
  				rhs_e->need_transpose = true;
  			}
  			else
  				statement(to_expression(lhs_expression), " = transpose(", to_unpacked_expression(rhs_expression), ");");
  
  			lhs_e->need_transpose = true;
  			register_write(lhs_expression);
  		}
  		else if (lhs_e && lhs_e->need_transpose)
  		{
  			lhs_e->need_transpose = false;
  
  			// Storing a column to a row-major matrix. Unroll the write.
  			for (uint32_t c = 0; c < type.vecsize; c++)
  			{
  				auto lhs_expr = to_dereferenced_expression(lhs_expression);
  				auto column_index = lhs_expr.find_last_of('[');
  				if (column_index != string::npos)
  				{
  					statement(lhs_expr.insert(column_index, join('[', c, ']')), " = ",
  					          to_extract_component_expression(rhs_expression, c), ";");
  				}
  			}
  			lhs_e->need_transpose = true;
  			register_write(lhs_expression);
  		}
  		else
  			CompilerGLSL::emit_store_statement(lhs_expression, rhs_expression);
  	}
  	else if (!lhs_remapped_type && !is_matrix(type) && !transpose)
  	{
  		// Even if the target type is packed, we can directly store to it. We cannot store to packed matrices directly,
  		// since they are declared as array of vectors instead, and we need the fallback path below.
  		CompilerGLSL::emit_store_statement(lhs_expression, rhs_expression);
  	}
  	else
  	{
  		// Special handling when storing to a remapped physical type.
  		// This is mostly to deal with std140 padded matrices or vectors.
  
  		TypeID physical_type_id = lhs_remapped_type ?
  		                              ID(get_extended_decoration(lhs_expression, SPIRVCrossDecorationPhysicalTypeID)) :
  		                              type.self;
  
  		auto &physical_type = get<SPIRType>(physical_type_id);
  
  		if (is_matrix(type))
  		{
  			const char *packed_pfx = lhs_packed_type ? "packed_" : "";
  
  			// Packed matrices are stored as arrays of packed vectors, so we need
  			// to assign the vectors one at a time.
  			// For row-major matrices, we need to transpose the *right-hand* side,
  			// not the left-hand side.
  
  			// Lots of cases to cover here ...
  
  			bool rhs_transpose = rhs_e && rhs_e->need_transpose;
  			SPIRType write_type = type;
  			string cast_expr;
  
  			// We're dealing with transpose manually.
  			if (rhs_transpose)
  				rhs_e->need_transpose = false;
  
  			if (transpose)
  			{
  				// We're dealing with transpose manually.
  				lhs_e->need_transpose = false;
  				write_type.vecsize = type.columns;
  				write_type.columns = 1;
  
  				if (physical_type.columns != type.columns)
  					cast_expr = join("(device ", packed_pfx, type_to_glsl(write_type), "&)");
  
  				if (rhs_transpose)
  				{
  					// If RHS is also transposed, we can just copy row by row.
  					for (uint32_t i = 0; i < type.vecsize; i++)
  					{
  						statement(cast_expr, to_enclosed_expression(lhs_expression), "[", i, "]", " = ",
  						          to_unpacked_row_major_matrix_expression(rhs_expression), "[", i, "];");
  					}
  				}
  				else
  				{
  					auto vector_type = expression_type(rhs_expression);
  					vector_type.vecsize = vector_type.columns;
  					vector_type.columns = 1;
  
  					// Transpose on the fly. Emitting a lot of full transpose() ops and extracting lanes seems very bad,
  					// so pick out individual components instead.
  					for (uint32_t i = 0; i < type.vecsize; i++)
  					{
  						string rhs_row = type_to_glsl_constructor(vector_type) + "(";
  						for (uint32_t j = 0; j < vector_type.vecsize; j++)
  						{
  							rhs_row += join(to_enclosed_unpacked_expression(rhs_expression), "[", j, "][", i, "]");
  							if (j + 1 < vector_type.vecsize)
  								rhs_row += ", ";
  						}
  						rhs_row += ")";
  
  						statement(cast_expr, to_enclosed_expression(lhs_expression), "[", i, "]", " = ", rhs_row, ";");
  					}
  				}
  
  				// We're dealing with transpose manually.
  				lhs_e->need_transpose = true;
  			}
  			else
  			{
  				write_type.columns = 1;
  
  				if (physical_type.vecsize != type.vecsize)
  					cast_expr = join("(device ", packed_pfx, type_to_glsl(write_type), "&)");
  
  				if (rhs_transpose)
  				{
  					auto vector_type = expression_type(rhs_expression);
  					vector_type.columns = 1;
  
  					// Transpose on the fly. Emitting a lot of full transpose() ops and extracting lanes seems very bad,
  					// so pick out individual components instead.
  					for (uint32_t i = 0; i < type.columns; i++)
  					{
  						string rhs_row = type_to_glsl_constructor(vector_type) + "(";
  						for (uint32_t j = 0; j < vector_type.vecsize; j++)
  						{
  							// Need to explicitly unpack expression since we've mucked with transpose state.
  							auto unpacked_expr = to_unpacked_row_major_matrix_expression(rhs_expression);
  							rhs_row += join(unpacked_expr, "[", j, "][", i, "]");
  							if (j + 1 < vector_type.vecsize)
  								rhs_row += ", ";
  						}
  						rhs_row += ")";
  
  						statement(cast_expr, to_enclosed_expression(lhs_expression), "[", i, "]", " = ", rhs_row, ";");
  					}
  				}
  				else
  				{
  					// Copy column-by-column.
  					for (uint32_t i = 0; i < type.columns; i++)
  					{
  						statement(cast_expr, to_enclosed_expression(lhs_expression), "[", i, "]", " = ",
  						          to_enclosed_unpacked_expression(rhs_expression), "[", i, "];");
  					}
  				}
  			}
  
  			// We're dealing with transpose manually.
  			if (rhs_transpose)
  				rhs_e->need_transpose = true;
  		}
  		else if (transpose)
  		{
  			lhs_e->need_transpose = false;
  
  			SPIRType write_type = type;
  			write_type.vecsize = 1;
  			write_type.columns = 1;
  
  			// Storing a column to a row-major matrix. Unroll the write.
  			for (uint32_t c = 0; c < type.vecsize; c++)
  			{
  				auto lhs_expr = to_enclosed_expression(lhs_expression);
  				auto column_index = lhs_expr.find_last_of('[');
  				if (column_index != string::npos)
  				{
  					statement("((device ", type_to_glsl(write_type), "*)&",
  					          lhs_expr.insert(column_index, join('[', c, ']', ")")), " = ",
  					          to_extract_component_expression(rhs_expression, c), ";");
  				}
  			}
  
  			lhs_e->need_transpose = true;
  		}
  		else if ((is_matrix(physical_type) || is_array(physical_type)) && physical_type.vecsize > type.vecsize)
  		{
  			assert(type.vecsize >= 1 && type.vecsize <= 3);
  
  			// If we have packed types, we cannot use swizzled stores.
  			// We could technically unroll the store for each element if needed.
  			// When remapping to a std140 physical type, we always get float4,
  			// and the packed decoration should always be removed.
  			assert(!lhs_packed_type);
  
  			string lhs = to_dereferenced_expression(lhs_expression);
  			string rhs = to_pointer_expression(rhs_expression);
  
  			// Unpack the expression so we can store to it with a float or float2.
  			// It's still an l-value, so it's fine. Most other unpacking of expressions turn them into r-values instead.
  			lhs = join("(device ", type_to_glsl(type), "&)", enclose_expression(lhs));
  			if (!optimize_read_modify_write(expression_type(rhs_expression), lhs, rhs))
  				statement(lhs, " = ", rhs, ";");
  		}
  		else if (!is_matrix(type))
  		{
  			string lhs = to_dereferenced_expression(lhs_expression);
  			string rhs = to_pointer_expression(rhs_expression);
  			if (!optimize_read_modify_write(expression_type(rhs_expression), lhs, rhs))
  				statement(lhs, " = ", rhs, ";");
  		}
  
  		register_write(lhs_expression);
  	}
  }
  
  static bool expression_ends_with(const string &expr_str, const std::string &ending)
  {
  	if (expr_str.length() >= ending.length())
  		return (expr_str.compare(expr_str.length() - ending.length(), ending.length(), ending) == 0);
  	else
  		return false;
  }
  
  // Converts the format of the current expression from packed to unpacked,
  // by wrapping the expression in a constructor of the appropriate type.
  // Also, handle special physical ID remapping scenarios, similar to emit_store_statement().
  string CompilerMSL::unpack_expression_type(string expr_str, const SPIRType &type, uint32_t physical_type_id,
                                             bool packed, bool row_major)
  {
  	// Trivial case, nothing to do.
  	if (physical_type_id == 0 && !packed)
  		return expr_str;
  
  	const SPIRType *physical_type = nullptr;
  	if (physical_type_id)
  		physical_type = &get<SPIRType>(physical_type_id);
  
  	static const char *swizzle_lut[] = {
  		".x",
  		".xy",
  		".xyz",
  	};
  
  	if (physical_type && is_vector(*physical_type) && is_array(*physical_type) &&
  	    physical_type->vecsize > type.vecsize && !expression_ends_with(expr_str, swizzle_lut[type.vecsize - 1]))
  	{
  		// std140 array cases for vectors.
  		assert(type.vecsize >= 1 && type.vecsize <= 3);
  		return enclose_expression(expr_str) + swizzle_lut[type.vecsize - 1];
  	}
  	else if (physical_type && is_matrix(*physical_type) && is_vector(type) && physical_type->vecsize > type.vecsize)
  	{
  		// Extract column from padded matrix.
  		assert(type.vecsize >= 1 && type.vecsize <= 3);
  		return enclose_expression(expr_str) + swizzle_lut[type.vecsize - 1];
  	}
  	else if (is_matrix(type))
  	{
  		// Packed matrices are stored as arrays of packed vectors. Unfortunately,
  		// we can't just pass the array straight to the matrix constructor. We have to
  		// pass each vector individually, so that they can be unpacked to normal vectors.
  		if (!physical_type)
  			physical_type = &type;
  
  		uint32_t vecsize = type.vecsize;
  		uint32_t columns = type.columns;
  		if (row_major)
  			swap(vecsize, columns);
  
  		uint32_t physical_vecsize = row_major ? physical_type->columns : physical_type->vecsize;
  
  		const char *base_type = type.width == 16 ? "half" : "float";
  		string unpack_expr = join(base_type, columns, "x", vecsize, "(");
  
  		const char *load_swiz = "";
  
  		if (physical_vecsize != vecsize)
  			load_swiz = swizzle_lut[vecsize - 1];
  
  		for (uint32_t i = 0; i < columns; i++)
  		{
  			if (i > 0)
  				unpack_expr += ", ";
  
  			if (packed)
  				unpack_expr += join(base_type, physical_vecsize, "(", expr_str, "[", i, "]", ")", load_swiz);
  			else
  				unpack_expr += join(expr_str, "[", i, "]", load_swiz);
  		}
  
  		unpack_expr += ")";
  		return unpack_expr;
  	}
  	else
  	{
  		return join(type_to_glsl(type), "(", expr_str, ")");
  	}
  }
  
  // Emits the file header info
  void CompilerMSL::emit_header()
  {
  	// This particular line can be overridden during compilation, so make it a flag and not a pragma line.
  	if (suppress_missing_prototypes)
  		statement("#pragma clang diagnostic ignored \"-Wmissing-prototypes\"");
  
  	// Disable warning about missing braces for array<T> template to make arrays a value type
  	if (spv_function_implementations.count(SPVFuncImplUnsafeArray) != 0)
  		statement("#pragma clang diagnostic ignored \"-Wmissing-braces\"");
  
  	for (auto &pragma : pragma_lines)
  		statement(pragma);
  
  	if (!pragma_lines.empty() || suppress_missing_prototypes)
  		statement("");
  
  	statement("#include <metal_stdlib>");
  	statement("#include <simd/simd.h>");
  
  	for (auto &header : header_lines)
  		statement(header);
  
  	statement("");
  	statement("using namespace metal;");
  	statement("");
  
  	for (auto &td : typedef_lines)
  		statement(td);
  
  	if (!typedef_lines.empty())
  		statement("");
  }
  
  void CompilerMSL::add_pragma_line(const string &line)
  {
  	auto rslt = pragma_lines.insert(line);
  	if (rslt.second)
  		force_recompile();
  }
  
  void CompilerMSL::add_typedef_line(const string &line)
  {
  	auto rslt = typedef_lines.insert(line);
  	if (rslt.second)
  		force_recompile();
  }
  
  // Template struct like spvUnsafeArray<> need to be declared *before* any resources are declared
  void CompilerMSL::emit_custom_templates()
  {
  	for (const auto &spv_func : spv_function_implementations)
  	{
  		switch (spv_func)
  		{
  		case SPVFuncImplUnsafeArray:
  			statement("template<typename T, size_t Num>");
  			statement("struct spvUnsafeArray");
  			begin_scope();
  			statement("T elements[Num ? Num : 1];");
  			statement("");
  			statement("thread T& operator [] (size_t pos) thread");
  			begin_scope();
  			statement("return elements[pos];");
  			end_scope();
  			statement("constexpr const thread T& operator [] (size_t pos) const thread");
  			begin_scope();
  			statement("return elements[pos];");
  			end_scope();
  			statement("");
  			statement("device T& operator [] (size_t pos) device");
  			begin_scope();
  			statement("return elements[pos];");
  			end_scope();
  			statement("constexpr const device T& operator [] (size_t pos) const device");
  			begin_scope();
  			statement("return elements[pos];");
  			end_scope();
  			statement("");
  			statement("constexpr const constant T& operator [] (size_t pos) const constant");
  			begin_scope();
  			statement("return elements[pos];");
  			end_scope();
  			statement("");
  			statement("threadgroup T& operator [] (size_t pos) threadgroup");
  			begin_scope();
  			statement("return elements[pos];");
  			end_scope();
  			statement("constexpr const threadgroup T& operator [] (size_t pos) const threadgroup");
  			begin_scope();
  			statement("return elements[pos];");
  			end_scope();
  			end_scope_decl();
  			statement("");
  			break;
  
  		default:
  			break;
  		}
  	}
  }
  
  // Emits any needed custom function bodies.
  // Metal helper functions must be static force-inline, i.e. static inline __attribute__((always_inline))
  // otherwise they will cause problems when linked together in a single Metallib.
  void CompilerMSL::emit_custom_functions()
  {
  	for (uint32_t i = kArrayCopyMultidimMax; i >= 2; i--)
  		if (spv_function_implementations.count(static_cast<SPVFuncImpl>(SPVFuncImplArrayCopyMultidimBase + i)))
  			spv_function_implementations.insert(static_cast<SPVFuncImpl>(SPVFuncImplArrayCopyMultidimBase + i - 1));
  
  	if (spv_function_implementations.count(SPVFuncImplDynamicImageSampler))
  	{
  		// Unfortunately, this one needs a lot of the other functions to compile OK.
  		if (!msl_options.supports_msl_version(2))
  			SPIRV_CROSS_THROW(
  			    "spvDynamicImageSampler requires default-constructible texture objects, which require MSL 2.0.");
  		spv_function_implementations.insert(SPVFuncImplForwardArgs);
  		spv_function_implementations.insert(SPVFuncImplTextureSwizzle);
  		if (msl_options.swizzle_texture_samples)
  			spv_function_implementations.insert(SPVFuncImplGatherSwizzle);
  		for (uint32_t i = SPVFuncImplChromaReconstructNearest2Plane;
  		     i <= SPVFuncImplChromaReconstructLinear420XMidpointYMidpoint3Plane; i++)
  			spv_function_implementations.insert(static_cast<SPVFuncImpl>(i));
  		spv_function_implementations.insert(SPVFuncImplExpandITUFullRange);
  		spv_function_implementations.insert(SPVFuncImplExpandITUNarrowRange);
  		spv_function_implementations.insert(SPVFuncImplConvertYCbCrBT709);
  		spv_function_implementations.insert(SPVFuncImplConvertYCbCrBT601);
  		spv_function_implementations.insert(SPVFuncImplConvertYCbCrBT2020);
  	}
  
  	for (uint32_t i = SPVFuncImplChromaReconstructNearest2Plane;
  	     i <= SPVFuncImplChromaReconstructLinear420XMidpointYMidpoint3Plane; i++)
  		if (spv_function_implementations.count(static_cast<SPVFuncImpl>(i)))
  			spv_function_implementations.insert(SPVFuncImplForwardArgs);
  
  	if (spv_function_implementations.count(SPVFuncImplTextureSwizzle) ||
  	    spv_function_implementations.count(SPVFuncImplGatherSwizzle) ||
  	    spv_function_implementations.count(SPVFuncImplGatherCompareSwizzle))
  	{
  		spv_function_implementations.insert(SPVFuncImplForwardArgs);
  		spv_function_implementations.insert(SPVFuncImplGetSwizzle);
  	}
  
  	for (const auto &spv_func : spv_function_implementations)
  	{
  		switch (spv_func)
  		{
  		case SPVFuncImplMod:
  			statement("// Implementation of the GLSL mod() function, which is slightly different than Metal fmod()");
  			statement("template<typename Tx, typename Ty>");
  			statement("inline Tx mod(Tx x, Ty y)");
  			begin_scope();
  			statement("return x - y * floor(x / y);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplRadians:
  			statement("// Implementation of the GLSL radians() function");
  			statement("template<typename T>");
  			statement("inline T radians(T d)");
  			begin_scope();
  			statement("return d * T(0.01745329251);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplDegrees:
  			statement("// Implementation of the GLSL degrees() function");
  			statement("template<typename T>");
  			statement("inline T degrees(T r)");
  			begin_scope();
  			statement("return r * T(57.2957795131);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplFindILsb:
  			statement("// Implementation of the GLSL findLSB() function");
  			statement("template<typename T>");
  			statement("inline T spvFindLSB(T x)");
  			begin_scope();
  			statement("return select(ctz(x), T(-1), x == T(0));");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplFindUMsb:
  			statement("// Implementation of the unsigned GLSL findMSB() function");
  			statement("template<typename T>");
  			statement("inline T spvFindUMSB(T x)");
  			begin_scope();
  			statement("return select(clz(T(0)) - (clz(x) + T(1)), T(-1), x == T(0));");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplFindSMsb:
  			statement("// Implementation of the signed GLSL findMSB() function");
  			statement("template<typename T>");
  			statement("inline T spvFindSMSB(T x)");
  			begin_scope();
  			statement("T v = select(x, T(-1) - x, x < T(0));");
  			statement("return select(clz(T(0)) - (clz(v) + T(1)), T(-1), v == T(0));");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplSSign:
  			statement("// Implementation of the GLSL sign() function for integer types");
  			statement("template<typename T, typename E = typename enable_if<is_integral<T>::value>::type>");
  			statement("inline T sign(T x)");
  			begin_scope();
  			statement("return select(select(select(x, T(0), x == T(0)), T(1), x > T(0)), T(-1), x < T(0));");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplArrayCopy:
  		case SPVFuncImplArrayOfArrayCopy2Dim:
  		case SPVFuncImplArrayOfArrayCopy3Dim:
  		case SPVFuncImplArrayOfArrayCopy4Dim:
  		case SPVFuncImplArrayOfArrayCopy5Dim:
  		case SPVFuncImplArrayOfArrayCopy6Dim:
  		{
  			// Unfortunately we cannot template on the address space, so combinatorial explosion it is.
  			static const char *function_name_tags[] = {
  				"FromConstantToStack",     "FromConstantToThreadGroup", "FromStackToStack",
  				"FromStackToThreadGroup",  "FromThreadGroupToStack",    "FromThreadGroupToThreadGroup",
  				"FromDeviceToDevice",      "FromConstantToDevice",      "FromStackToDevice",
  				"FromThreadGroupToDevice", "FromDeviceToStack",         "FromDeviceToThreadGroup",
  			};
  
  			static const char *src_address_space[] = {
  				"constant",          "constant",          "thread const", "thread const",
  				"threadgroup const", "threadgroup const", "device const", "constant",
  				"thread const",      "threadgroup const", "device const", "device const",
  			};
  
  			static const char *dst_address_space[] = {
  				"thread", "threadgroup", "thread", "threadgroup", "thread", "threadgroup",
  				"device", "device",      "device", "device",      "thread", "threadgroup",
  			};
  
  			for (uint32_t variant = 0; variant < 12; variant++)
  			{
  				uint32_t dimensions = spv_func - SPVFuncImplArrayCopyMultidimBase;
  				string tmp = "template<typename T";
  				for (uint8_t i = 0; i < dimensions; i++)
  				{
  					tmp += ", uint ";
  					tmp += 'A' + i;
  				}
  				tmp += ">";
  				statement(tmp);
  
  				string array_arg;
  				for (uint8_t i = 0; i < dimensions; i++)
  				{
  					array_arg += "[";
  					array_arg += 'A' + i;
  					array_arg += "]";
  				}
  
  				statement("inline void spvArrayCopy", function_name_tags[variant], dimensions, "(",
  				          dst_address_space[variant], " T (&dst)", array_arg, ", ", src_address_space[variant],
  				          " T (&src)", array_arg, ")");
  
  				begin_scope();
  				statement("for (uint i = 0; i < A; i++)");
  				begin_scope();
  
  				if (dimensions == 1)
  					statement("dst[i] = src[i];");
  				else
  					statement("spvArrayCopy", function_name_tags[variant], dimensions - 1, "(dst[i], src[i]);");
  				end_scope();
  				end_scope();
  				statement("");
  			}
  			break;
  		}
  
  		// Support for Metal 2.1's new texture_buffer type.
  		case SPVFuncImplTexelBufferCoords:
  		{
  			if (msl_options.texel_buffer_texture_width > 0)
  			{
  				string tex_width_str = convert_to_string(msl_options.texel_buffer_texture_width);
  				statement("// Returns 2D texture coords corresponding to 1D texel buffer coords");
  				statement(force_inline);
  				statement("uint2 spvTexelBufferCoord(uint tc)");
  				begin_scope();
  				statement(join("return uint2(tc % ", tex_width_str, ", tc / ", tex_width_str, ");"));
  				end_scope();
  				statement("");
  			}
  			else
  			{
  				statement("// Returns 2D texture coords corresponding to 1D texel buffer coords");
  				statement(
  				    "#define spvTexelBufferCoord(tc, tex) uint2((tc) % (tex).get_width(), (tc) / (tex).get_width())");
  				statement("");
  			}
  			break;
  		}
  
  		// Emulate texture2D atomic operations
  		case SPVFuncImplImage2DAtomicCoords:
  		{
  			if (msl_options.supports_msl_version(1, 2))
  			{
  				statement("// The required alignment of a linear texture of R32Uint format.");
  				statement("constant uint spvLinearTextureAlignmentOverride [[function_constant(",
  				          msl_options.r32ui_alignment_constant_id, ")]];");
  				statement("constant uint spvLinearTextureAlignment = ",
  				          "is_function_constant_defined(spvLinearTextureAlignmentOverride) ? ",
  				          "spvLinearTextureAlignmentOverride : ", msl_options.r32ui_linear_texture_alignment, ";");
  			}
  			else
  			{
  				statement("// The required alignment of a linear texture of R32Uint format.");
  				statement("constant uint spvLinearTextureAlignment = ", msl_options.r32ui_linear_texture_alignment,
  				          ";");
  			}
  			statement("// Returns buffer coords corresponding to 2D texture coords for emulating 2D texture atomics");
  			statement("#define spvImage2DAtomicCoord(tc, tex) (((((tex).get_width() + ",
  			          " spvLinearTextureAlignment / 4 - 1) & ~(",
  			          " spvLinearTextureAlignment / 4 - 1)) * (tc).y) + (tc).x)");
  			statement("");
  			break;
  		}
  
  		// "fadd" intrinsic support
  		case SPVFuncImplFAdd:
  			statement("template<typename T>");
  			statement("T spvFAdd(T l, T r)");
  			begin_scope();
  			statement("return fma(T(1), l, r);");
  			end_scope();
  			statement("");
  			break;
  
  		// "fsub" intrinsic support
  		case SPVFuncImplFSub:
  			statement("template<typename T>");
  			statement("T spvFSub(T l, T r)");
  			begin_scope();
  			statement("return fma(T(-1), r, l);");
  			end_scope();
  			statement("");
  			break;
  
  		// "fmul' intrinsic support
  		case SPVFuncImplFMul:
  			statement("template<typename T>");
  			statement("T spvFMul(T l, T r)");
  			begin_scope();
  			statement("return fma(l, r, T(0));");
  			end_scope();
  			statement("");
  
  			statement("template<typename T, int Cols, int Rows>");
  			statement("vec<T, Cols> spvFMulVectorMatrix(vec<T, Rows> v, matrix<T, Cols, Rows> m)");
  			begin_scope();
  			statement("vec<T, Cols> res = vec<T, Cols>(0);");
  			statement("for (uint i = Rows; i > 0; --i)");
  			begin_scope();
  			statement("vec<T, Cols> tmp(0);");
  			statement("for (uint j = 0; j < Cols; ++j)");
  			begin_scope();
  			statement("tmp[j] = m[j][i - 1];");
  			end_scope();
  			statement("res = fma(tmp, vec<T, Cols>(v[i - 1]), res);");
  			end_scope();
  			statement("return res;");
  			end_scope();
  			statement("");
  
  			statement("template<typename T, int Cols, int Rows>");
  			statement("vec<T, Rows> spvFMulMatrixVector(matrix<T, Cols, Rows> m, vec<T, Cols> v)");
  			begin_scope();
  			statement("vec<T, Rows> res = vec<T, Rows>(0);");
  			statement("for (uint i = Cols; i > 0; --i)");
  			begin_scope();
  			statement("res = fma(m[i - 1], vec<T, Rows>(v[i - 1]), res);");
  			end_scope();
  			statement("return res;");
  			end_scope();
  			statement("");
  
  			statement("template<typename T, int LCols, int LRows, int RCols, int RRows>");
  			statement(
  			    "matrix<T, RCols, LRows> spvFMulMatrixMatrix(matrix<T, LCols, LRows> l, matrix<T, RCols, RRows> r)");
  			begin_scope();
  			statement("matrix<T, RCols, LRows> res;");
  			statement("for (uint i = 0; i < RCols; i++)");
  			begin_scope();
  			statement("vec<T, RCols> tmp(0);");
  			statement("for (uint j = 0; j < LCols; j++)");
  			begin_scope();
  			statement("tmp = fma(vec<T, RCols>(r[i][j]), l[j], tmp);");
  			end_scope();
  			statement("res[i] = tmp;");
  			end_scope();
  			statement("return res;");
  			end_scope();
  			statement("");
  			break;
  
  		// Emulate texturecube_array with texture2d_array for iOS where this type is not available
  		case SPVFuncImplCubemapTo2DArrayFace:
  			statement(force_inline);
  			statement("float3 spvCubemapTo2DArrayFace(float3 P)");
  			begin_scope();
  			statement("float3 Coords = abs(P.xyz);");
  			statement("float CubeFace = 0;");
  			statement("float ProjectionAxis = 0;");
  			statement("float u = 0;");
  			statement("float v = 0;");
  			statement("if (Coords.x >= Coords.y && Coords.x >= Coords.z)");
  			begin_scope();
  			statement("CubeFace = P.x >= 0 ? 0 : 1;");
  			statement("ProjectionAxis = Coords.x;");
  			statement("u = P.x >= 0 ? -P.z : P.z;");
  			statement("v = -P.y;");
  			end_scope();
  			statement("else if (Coords.y >= Coords.x && Coords.y >= Coords.z)");
  			begin_scope();
  			statement("CubeFace = P.y >= 0 ? 2 : 3;");
  			statement("ProjectionAxis = Coords.y;");
  			statement("u = P.x;");
  			statement("v = P.y >= 0 ? P.z : -P.z;");
  			end_scope();
  			statement("else");
  			begin_scope();
  			statement("CubeFace = P.z >= 0 ? 4 : 5;");
  			statement("ProjectionAxis = Coords.z;");
  			statement("u = P.z >= 0 ? P.x : -P.x;");
  			statement("v = -P.y;");
  			end_scope();
  			statement("u = 0.5 * (u/ProjectionAxis + 1);");
  			statement("v = 0.5 * (v/ProjectionAxis + 1);");
  			statement("return float3(u, v, CubeFace);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplInverse4x4:
  			statement("// Returns the determinant of a 2x2 matrix.");
  			statement(force_inline);
  			statement("float spvDet2x2(float a1, float a2, float b1, float b2)");
  			begin_scope();
  			statement("return a1 * b2 - b1 * a2;");
  			end_scope();
  			statement("");
  
  			statement("// Returns the determinant of a 3x3 matrix.");
  			statement(force_inline);
  			statement("float spvDet3x3(float a1, float a2, float a3, float b1, float b2, float b3, float c1, "
  			          "float c2, float c3)");
  			begin_scope();
  			statement("return a1 * spvDet2x2(b2, b3, c2, c3) - b1 * spvDet2x2(a2, a3, c2, c3) + c1 * spvDet2x2(a2, a3, "
  			          "b2, b3);");
  			end_scope();
  			statement("");
  			statement("// Returns the inverse of a matrix, by using the algorithm of calculating the classical");
  			statement("// adjoint and dividing by the determinant. The contents of the matrix are changed.");
  			statement(force_inline);
  			statement("float4x4 spvInverse4x4(float4x4 m)");
  			begin_scope();
  			statement("float4x4 adj;	// The adjoint matrix (inverse after dividing by determinant)");
  			statement_no_indent("");
  			statement("// Create the transpose of the cofactors, as the classical adjoint of the matrix.");
  			statement("adj[0][0] =  spvDet3x3(m[1][1], m[1][2], m[1][3], m[2][1], m[2][2], m[2][3], m[3][1], m[3][2], "
  			          "m[3][3]);");
  			statement("adj[0][1] = -spvDet3x3(m[0][1], m[0][2], m[0][3], m[2][1], m[2][2], m[2][3], m[3][1], m[3][2], "
  			          "m[3][3]);");
  			statement("adj[0][2] =  spvDet3x3(m[0][1], m[0][2], m[0][3], m[1][1], m[1][2], m[1][3], m[3][1], m[3][2], "
  			          "m[3][3]);");
  			statement("adj[0][3] = -spvDet3x3(m[0][1], m[0][2], m[0][3], m[1][1], m[1][2], m[1][3], m[2][1], m[2][2], "
  			          "m[2][3]);");
  			statement_no_indent("");
  			statement("adj[1][0] = -spvDet3x3(m[1][0], m[1][2], m[1][3], m[2][0], m[2][2], m[2][3], m[3][0], m[3][2], "
  			          "m[3][3]);");
  			statement("adj[1][1] =  spvDet3x3(m[0][0], m[0][2], m[0][3], m[2][0], m[2][2], m[2][3], m[3][0], m[3][2], "
  			          "m[3][3]);");
  			statement("adj[1][2] = -spvDet3x3(m[0][0], m[0][2], m[0][3], m[1][0], m[1][2], m[1][3], m[3][0], m[3][2], "
  			          "m[3][3]);");
  			statement("adj[1][3] =  spvDet3x3(m[0][0], m[0][2], m[0][3], m[1][0], m[1][2], m[1][3], m[2][0], m[2][2], "
  			          "m[2][3]);");
  			statement_no_indent("");
  			statement("adj[2][0] =  spvDet3x3(m[1][0], m[1][1], m[1][3], m[2][0], m[2][1], m[2][3], m[3][0], m[3][1], "
  			          "m[3][3]);");
  			statement("adj[2][1] = -spvDet3x3(m[0][0], m[0][1], m[0][3], m[2][0], m[2][1], m[2][3], m[3][0], m[3][1], "
  			          "m[3][3]);");
  			statement("adj[2][2] =  spvDet3x3(m[0][0], m[0][1], m[0][3], m[1][0], m[1][1], m[1][3], m[3][0], m[3][1], "
  			          "m[3][3]);");
  			statement("adj[2][3] = -spvDet3x3(m[0][0], m[0][1], m[0][3], m[1][0], m[1][1], m[1][3], m[2][0], m[2][1], "
  			          "m[2][3]);");
  			statement_no_indent("");
  			statement("adj[3][0] = -spvDet3x3(m[1][0], m[1][1], m[1][2], m[2][0], m[2][1], m[2][2], m[3][0], m[3][1], "
  			          "m[3][2]);");
  			statement("adj[3][1] =  spvDet3x3(m[0][0], m[0][1], m[0][2], m[2][0], m[2][1], m[2][2], m[3][0], m[3][1], "
  			          "m[3][2]);");
  			statement("adj[3][2] = -spvDet3x3(m[0][0], m[0][1], m[0][2], m[1][0], m[1][1], m[1][2], m[3][0], m[3][1], "
  			          "m[3][2]);");
  			statement("adj[3][3] =  spvDet3x3(m[0][0], m[0][1], m[0][2], m[1][0], m[1][1], m[1][2], m[2][0], m[2][1], "
  			          "m[2][2]);");
  			statement_no_indent("");
  			statement("// Calculate the determinant as a combination of the cofactors of the first row.");
  			statement("float det = (adj[0][0] * m[0][0]) + (adj[0][1] * m[1][0]) + (adj[0][2] * m[2][0]) + (adj[0][3] "
  			          "* m[3][0]);");
  			statement_no_indent("");
  			statement("// Divide the classical adjoint matrix by the determinant.");
  			statement("// If determinant is zero, matrix is not invertable, so leave it unchanged.");
  			statement("return (det != 0.0f) ? (adj * (1.0f / det)) : m;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplInverse3x3:
  			if (spv_function_implementations.count(SPVFuncImplInverse4x4) == 0)
  			{
  				statement("// Returns the determinant of a 2x2 matrix.");
  				statement(force_inline);
  				statement("float spvDet2x2(float a1, float a2, float b1, float b2)");
  				begin_scope();
  				statement("return a1 * b2 - b1 * a2;");
  				end_scope();
  				statement("");
  			}
  
  			statement("// Returns the inverse of a matrix, by using the algorithm of calculating the classical");
  			statement("// adjoint and dividing by the determinant. The contents of the matrix are changed.");
  			statement(force_inline);
  			statement("float3x3 spvInverse3x3(float3x3 m)");
  			begin_scope();
  			statement("float3x3 adj;	// The adjoint matrix (inverse after dividing by determinant)");
  			statement_no_indent("");
  			statement("// Create the transpose of the cofactors, as the classical adjoint of the matrix.");
  			statement("adj[0][0] =  spvDet2x2(m[1][1], m[1][2], m[2][1], m[2][2]);");
  			statement("adj[0][1] = -spvDet2x2(m[0][1], m[0][2], m[2][1], m[2][2]);");
  			statement("adj[0][2] =  spvDet2x2(m[0][1], m[0][2], m[1][1], m[1][2]);");
  			statement_no_indent("");
  			statement("adj[1][0] = -spvDet2x2(m[1][0], m[1][2], m[2][0], m[2][2]);");
  			statement("adj[1][1] =  spvDet2x2(m[0][0], m[0][2], m[2][0], m[2][2]);");
  			statement("adj[1][2] = -spvDet2x2(m[0][0], m[0][2], m[1][0], m[1][2]);");
  			statement_no_indent("");
  			statement("adj[2][0] =  spvDet2x2(m[1][0], m[1][1], m[2][0], m[2][1]);");
  			statement("adj[2][1] = -spvDet2x2(m[0][0], m[0][1], m[2][0], m[2][1]);");
  			statement("adj[2][2] =  spvDet2x2(m[0][0], m[0][1], m[1][0], m[1][1]);");
  			statement_no_indent("");
  			statement("// Calculate the determinant as a combination of the cofactors of the first row.");
  			statement("float det = (adj[0][0] * m[0][0]) + (adj[0][1] * m[1][0]) + (adj[0][2] * m[2][0]);");
  			statement_no_indent("");
  			statement("// Divide the classical adjoint matrix by the determinant.");
  			statement("// If determinant is zero, matrix is not invertable, so leave it unchanged.");
  			statement("return (det != 0.0f) ? (adj * (1.0f / det)) : m;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplInverse2x2:
  			statement("// Returns the inverse of a matrix, by using the algorithm of calculating the classical");
  			statement("// adjoint and dividing by the determinant. The contents of the matrix are changed.");
  			statement(force_inline);
  			statement("float2x2 spvInverse2x2(float2x2 m)");
  			begin_scope();
  			statement("float2x2 adj;	// The adjoint matrix (inverse after dividing by determinant)");
  			statement_no_indent("");
  			statement("// Create the transpose of the cofactors, as the classical adjoint of the matrix.");
  			statement("adj[0][0] =  m[1][1];");
  			statement("adj[0][1] = -m[0][1];");
  			statement_no_indent("");
  			statement("adj[1][0] = -m[1][0];");
  			statement("adj[1][1] =  m[0][0];");
  			statement_no_indent("");
  			statement("// Calculate the determinant as a combination of the cofactors of the first row.");
  			statement("float det = (adj[0][0] * m[0][0]) + (adj[0][1] * m[1][0]);");
  			statement_no_indent("");
  			statement("// Divide the classical adjoint matrix by the determinant.");
  			statement("// If determinant is zero, matrix is not invertable, so leave it unchanged.");
  			statement("return (det != 0.0f) ? (adj * (1.0f / det)) : m;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplForwardArgs:
  			statement("template<typename T> struct spvRemoveReference { typedef T type; };");
  			statement("template<typename T> struct spvRemoveReference<thread T&> { typedef T type; };");
  			statement("template<typename T> struct spvRemoveReference<thread T&&> { typedef T type; };");
  			statement("template<typename T> inline constexpr thread T&& spvForward(thread typename "
  			          "spvRemoveReference<T>::type& x)");
  			begin_scope();
  			statement("return static_cast<thread T&&>(x);");
  			end_scope();
  			statement("template<typename T> inline constexpr thread T&& spvForward(thread typename "
  			          "spvRemoveReference<T>::type&& x)");
  			begin_scope();
  			statement("return static_cast<thread T&&>(x);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplGetSwizzle:
  			statement("enum class spvSwizzle : uint");
  			begin_scope();
  			statement("none = 0,");
  			statement("zero,");
  			statement("one,");
  			statement("red,");
  			statement("green,");
  			statement("blue,");
  			statement("alpha");
  			end_scope_decl();
  			statement("");
  			statement("template<typename T>");
  			statement("inline T spvGetSwizzle(vec<T, 4> x, T c, spvSwizzle s)");
  			begin_scope();
  			statement("switch (s)");
  			begin_scope();
  			statement("case spvSwizzle::none:");
  			statement("    return c;");
  			statement("case spvSwizzle::zero:");
  			statement("    return 0;");
  			statement("case spvSwizzle::one:");
  			statement("    return 1;");
  			statement("case spvSwizzle::red:");
  			statement("    return x.r;");
  			statement("case spvSwizzle::green:");
  			statement("    return x.g;");
  			statement("case spvSwizzle::blue:");
  			statement("    return x.b;");
  			statement("case spvSwizzle::alpha:");
  			statement("    return x.a;");
  			end_scope();
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplTextureSwizzle:
  			statement("// Wrapper function that swizzles texture samples and fetches.");
  			statement("template<typename T>");
  			statement("inline vec<T, 4> spvTextureSwizzle(vec<T, 4> x, uint s)");
  			begin_scope();
  			statement("if (!s)");
  			statement("    return x;");
  			statement("return vec<T, 4>(spvGetSwizzle(x, x.r, spvSwizzle((s >> 0) & 0xFF)), "
  			          "spvGetSwizzle(x, x.g, spvSwizzle((s >> 8) & 0xFF)), spvGetSwizzle(x, x.b, spvSwizzle((s >> 16) "
  			          "& 0xFF)), "
  			          "spvGetSwizzle(x, x.a, spvSwizzle((s >> 24) & 0xFF)));");
  			end_scope();
  			statement("");
  			statement("template<typename T>");
  			statement("inline T spvTextureSwizzle(T x, uint s)");
  			begin_scope();
  			statement("return spvTextureSwizzle(vec<T, 4>(x, 0, 0, 1), s).x;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplGatherSwizzle:
  			statement("// Wrapper function that swizzles texture gathers.");
  			statement("template<typename T, template<typename, access = access::sample, typename = void> class Tex, "
  			          "typename... Ts>");
  			statement("inline vec<T, 4> spvGatherSwizzle(const thread Tex<T>& t, sampler s, "
  			          "uint sw, component c, Ts... params) METAL_CONST_ARG(c)");
  			begin_scope();
  			statement("if (sw)");
  			begin_scope();
  			statement("switch (spvSwizzle((sw >> (uint(c) * 8)) & 0xFF))");
  			begin_scope();
  			statement("case spvSwizzle::none:");
  			statement("    break;");
  			statement("case spvSwizzle::zero:");
  			statement("    return vec<T, 4>(0, 0, 0, 0);");
  			statement("case spvSwizzle::one:");
  			statement("    return vec<T, 4>(1, 1, 1, 1);");
  			statement("case spvSwizzle::red:");
  			statement("    return t.gather(s, spvForward<Ts>(params)..., component::x);");
  			statement("case spvSwizzle::green:");
  			statement("    return t.gather(s, spvForward<Ts>(params)..., component::y);");
  			statement("case spvSwizzle::blue:");
  			statement("    return t.gather(s, spvForward<Ts>(params)..., component::z);");
  			statement("case spvSwizzle::alpha:");
  			statement("    return t.gather(s, spvForward<Ts>(params)..., component::w);");
  			end_scope();
  			end_scope();
  			// texture::gather insists on its component parameter being a constant
  			// expression, so we need this silly workaround just to compile the shader.
  			statement("switch (c)");
  			begin_scope();
  			statement("case component::x:");
  			statement("    return t.gather(s, spvForward<Ts>(params)..., component::x);");
  			statement("case component::y:");
  			statement("    return t.gather(s, spvForward<Ts>(params)..., component::y);");
  			statement("case component::z:");
  			statement("    return t.gather(s, spvForward<Ts>(params)..., component::z);");
  			statement("case component::w:");
  			statement("    return t.gather(s, spvForward<Ts>(params)..., component::w);");
  			end_scope();
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplGatherCompareSwizzle:
  			statement("// Wrapper function that swizzles depth texture gathers.");
  			statement("template<typename T, template<typename, access = access::sample, typename = void> class Tex, "
  			          "typename... Ts>");
  			statement("inline vec<T, 4> spvGatherCompareSwizzle(const thread Tex<T>& t, sampler "
  			          "s, uint sw, Ts... params) ");
  			begin_scope();
  			statement("if (sw)");
  			begin_scope();
  			statement("switch (spvSwizzle(sw & 0xFF))");
  			begin_scope();
  			statement("case spvSwizzle::none:");
  			statement("case spvSwizzle::red:");
  			statement("    break;");
  			statement("case spvSwizzle::zero:");
  			statement("case spvSwizzle::green:");
  			statement("case spvSwizzle::blue:");
  			statement("case spvSwizzle::alpha:");
  			statement("    return vec<T, 4>(0, 0, 0, 0);");
  			statement("case spvSwizzle::one:");
  			statement("    return vec<T, 4>(1, 1, 1, 1);");
  			end_scope();
  			end_scope();
  			statement("return t.gather_compare(s, spvForward<Ts>(params)...);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplSubgroupBroadcast:
  			// Metal doesn't allow broadcasting boolean values directly, but we can work around that by broadcasting
  			// them as integers.
  			statement("template<typename T>");
  			statement("inline T spvSubgroupBroadcast(T value, ushort lane)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return quad_broadcast(value, lane);");
  			else
  				statement("return simd_broadcast(value, lane);");
  			end_scope();
  			statement("");
  			statement("template<>");
  			statement("inline bool spvSubgroupBroadcast(bool value, ushort lane)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return !!quad_broadcast((ushort)value, lane);");
  			else
  				statement("return !!simd_broadcast((ushort)value, lane);");
  			end_scope();
  			statement("");
  			statement("template<uint N>");
  			statement("inline vec<bool, N> spvSubgroupBroadcast(vec<bool, N> value, ushort lane)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return (vec<bool, N>)quad_broadcast((vec<ushort, N>)value, lane);");
  			else
  				statement("return (vec<bool, N>)simd_broadcast((vec<ushort, N>)value, lane);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplSubgroupBroadcastFirst:
  			statement("template<typename T>");
  			statement("inline T spvSubgroupBroadcastFirst(T value)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return quad_broadcast_first(value);");
  			else
  				statement("return simd_broadcast_first(value);");
  			end_scope();
  			statement("");
  			statement("template<>");
  			statement("inline bool spvSubgroupBroadcastFirst(bool value)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return !!quad_broadcast_first((ushort)value);");
  			else
  				statement("return !!simd_broadcast_first((ushort)value);");
  			end_scope();
  			statement("");
  			statement("template<uint N>");
  			statement("inline vec<bool, N> spvSubgroupBroadcastFirst(vec<bool, N> value)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return (vec<bool, N>)quad_broadcast_first((vec<ushort, N>)value);");
  			else
  				statement("return (vec<bool, N>)simd_broadcast_first((vec<ushort, N>)value);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplSubgroupBallot:
  			statement("inline uint4 spvSubgroupBallot(bool value)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  			{
  				statement("return uint4((quad_vote::vote_t)quad_ballot(value), 0, 0, 0);");
  			}
  			else if (msl_options.is_ios())
  			{
  				// The current simd_vote on iOS uses a 32-bit integer-like object.
  				statement("return uint4((simd_vote::vote_t)simd_ballot(value), 0, 0, 0);");
  			}
  			else
  			{
  				statement("simd_vote vote = simd_ballot(value);");
  				statement("// simd_ballot() returns a 64-bit integer-like object, but");
  				statement("// SPIR-V callers expect a uint4. We must convert.");
  				statement("// FIXME: This won't include higher bits if Apple ever supports");
  				statement("// 128 lanes in an SIMD-group.");
  				statement("return uint4(as_type<uint2>((simd_vote::vote_t)vote), 0, 0);");
  			}
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplSubgroupBallotBitExtract:
  			statement("inline bool spvSubgroupBallotBitExtract(uint4 ballot, uint bit)");
  			begin_scope();
  			statement("return !!extract_bits(ballot[bit / 32], bit % 32, 1);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplSubgroupBallotFindLSB:
  			statement("inline uint spvSubgroupBallotFindLSB(uint4 ballot, uint gl_SubgroupSize)");
  			begin_scope();
  			if (msl_options.is_ios())
  			{
  				statement("uint4 mask = uint4(extract_bits(0xFFFFFFFF, 0, gl_SubgroupSize), uint3(0));");
  			}
  			else
  			{
  				statement("uint4 mask = uint4(extract_bits(0xFFFFFFFF, 0, min(gl_SubgroupSize, 32u)), "
  				          "extract_bits(0xFFFFFFFF, 0, (uint)max((int)gl_SubgroupSize - 32, 0)), uint2(0));");
  			}
  			statement("ballot &= mask;");
  			statement("return select(ctz(ballot.x), select(32 + ctz(ballot.y), select(64 + ctz(ballot.z), select(96 + "
  			          "ctz(ballot.w), uint(-1), ballot.w == 0), ballot.z == 0), ballot.y == 0), ballot.x == 0);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplSubgroupBallotFindMSB:
  			statement("inline uint spvSubgroupBallotFindMSB(uint4 ballot, uint gl_SubgroupSize)");
  			begin_scope();
  			if (msl_options.is_ios())
  			{
  				statement("uint4 mask = uint4(extract_bits(0xFFFFFFFF, 0, gl_SubgroupSize), uint3(0));");
  			}
  			else
  			{
  				statement("uint4 mask = uint4(extract_bits(0xFFFFFFFF, 0, min(gl_SubgroupSize, 32u)), "
  				          "extract_bits(0xFFFFFFFF, 0, (uint)max((int)gl_SubgroupSize - 32, 0)), uint2(0));");
  			}
  			statement("ballot &= mask;");
  			statement("return select(128 - (clz(ballot.w) + 1), select(96 - (clz(ballot.z) + 1), select(64 - "
  			          "(clz(ballot.y) + 1), select(32 - (clz(ballot.x) + 1), uint(-1), ballot.x == 0), ballot.y == 0), "
  			          "ballot.z == 0), ballot.w == 0);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplSubgroupBallotBitCount:
  			statement("inline uint spvPopCount4(uint4 ballot)");
  			begin_scope();
  			statement("return popcount(ballot.x) + popcount(ballot.y) + popcount(ballot.z) + popcount(ballot.w);");
  			end_scope();
  			statement("");
  			statement("inline uint spvSubgroupBallotBitCount(uint4 ballot, uint gl_SubgroupSize)");
  			begin_scope();
  			if (msl_options.is_ios())
  			{
  				statement("uint4 mask = uint4(extract_bits(0xFFFFFFFF, 0, gl_SubgroupSize), uint3(0));");
  			}
  			else
  			{
  				statement("uint4 mask = uint4(extract_bits(0xFFFFFFFF, 0, min(gl_SubgroupSize, 32u)), "
  				          "extract_bits(0xFFFFFFFF, 0, (uint)max((int)gl_SubgroupSize - 32, 0)), uint2(0));");
  			}
  			statement("return spvPopCount4(ballot & mask);");
  			end_scope();
  			statement("");
  			statement("inline uint spvSubgroupBallotInclusiveBitCount(uint4 ballot, uint gl_SubgroupInvocationID)");
  			begin_scope();
  			if (msl_options.is_ios())
  			{
  				statement("uint4 mask = uint4(extract_bits(0xFFFFFFFF, 0, gl_SubgroupInvocationID + 1), uint3(0));");
  			}
  			else
  			{
  				statement("uint4 mask = uint4(extract_bits(0xFFFFFFFF, 0, min(gl_SubgroupInvocationID + 1, 32u)), "
  				          "extract_bits(0xFFFFFFFF, 0, (uint)max((int)gl_SubgroupInvocationID + 1 - 32, 0)), "
  				          "uint2(0));");
  			}
  			statement("return spvPopCount4(ballot & mask);");
  			end_scope();
  			statement("");
  			statement("inline uint spvSubgroupBallotExclusiveBitCount(uint4 ballot, uint gl_SubgroupInvocationID)");
  			begin_scope();
  			if (msl_options.is_ios())
  			{
  				statement("uint4 mask = uint4(extract_bits(0xFFFFFFFF, 0, gl_SubgroupInvocationID), uint2(0));");
  			}
  			else
  			{
  				statement("uint4 mask = uint4(extract_bits(0xFFFFFFFF, 0, min(gl_SubgroupInvocationID, 32u)), "
  				          "extract_bits(0xFFFFFFFF, 0, (uint)max((int)gl_SubgroupInvocationID - 32, 0)), uint2(0));");
  			}
  			statement("return spvPopCount4(ballot & mask);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplSubgroupAllEqual:
  			// Metal doesn't provide a function to evaluate this directly. But, we can
  			// implement this by comparing every thread's value to one thread's value
  			// (in this case, the value of the first active thread). Then, by the transitive
  			// property of equality, if all comparisons return true, then they are all equal.
  			statement("template<typename T>");
  			statement("inline bool spvSubgroupAllEqual(T value)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return quad_all(all(value == quad_broadcast_first(value)));");
  			else
  				statement("return simd_all(all(value == simd_broadcast_first(value)));");
  			end_scope();
  			statement("");
  			statement("template<>");
  			statement("inline bool spvSubgroupAllEqual(bool value)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return quad_all(value) || !quad_any(value);");
  			else
  				statement("return simd_all(value) || !simd_any(value);");
  			end_scope();
  			statement("");
  			statement("template<uint N>");
  			statement("inline bool spvSubgroupAllEqual(vec<bool, N> value)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return quad_all(all(value == (vec<bool, N>)quad_broadcast_first((vec<ushort, N>)value)));");
  			else
  				statement("return simd_all(all(value == (vec<bool, N>)simd_broadcast_first((vec<ushort, N>)value)));");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplSubgroupShuffle:
  			statement("template<typename T>");
  			statement("inline T spvSubgroupShuffle(T value, ushort lane)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return quad_shuffle(value, lane);");
  			else
  				statement("return simd_shuffle(value, lane);");
  			end_scope();
  			statement("");
  			statement("template<>");
  			statement("inline bool spvSubgroupShuffle(bool value, ushort lane)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return !!quad_shuffle((ushort)value, lane);");
  			else
  				statement("return !!simd_shuffle((ushort)value, lane);");
  			end_scope();
  			statement("");
  			statement("template<uint N>");
  			statement("inline vec<bool, N> spvSubgroupShuffle(vec<bool, N> value, ushort lane)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return (vec<bool, N>)quad_shuffle((vec<ushort, N>)value, lane);");
  			else
  				statement("return (vec<bool, N>)simd_shuffle((vec<ushort, N>)value, lane);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplSubgroupShuffleXor:
  			statement("template<typename T>");
  			statement("inline T spvSubgroupShuffleXor(T value, ushort mask)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return quad_shuffle_xor(value, mask);");
  			else
  				statement("return simd_shuffle_xor(value, mask);");
  			end_scope();
  			statement("");
  			statement("template<>");
  			statement("inline bool spvSubgroupShuffleXor(bool value, ushort mask)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return !!quad_shuffle_xor((ushort)value, mask);");
  			else
  				statement("return !!simd_shuffle_xor((ushort)value, mask);");
  			end_scope();
  			statement("");
  			statement("template<uint N>");
  			statement("inline vec<bool, N> spvSubgroupShuffleXor(vec<bool, N> value, ushort mask)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return (vec<bool, N>)quad_shuffle_xor((vec<ushort, N>)value, mask);");
  			else
  				statement("return (vec<bool, N>)simd_shuffle_xor((vec<ushort, N>)value, mask);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplSubgroupShuffleUp:
  			statement("template<typename T>");
  			statement("inline T spvSubgroupShuffleUp(T value, ushort delta)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return quad_shuffle_up(value, delta);");
  			else
  				statement("return simd_shuffle_up(value, delta);");
  			end_scope();
  			statement("");
  			statement("template<>");
  			statement("inline bool spvSubgroupShuffleUp(bool value, ushort delta)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return !!quad_shuffle_up((ushort)value, delta);");
  			else
  				statement("return !!simd_shuffle_up((ushort)value, delta);");
  			end_scope();
  			statement("");
  			statement("template<uint N>");
  			statement("inline vec<bool, N> spvSubgroupShuffleUp(vec<bool, N> value, ushort delta)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return (vec<bool, N>)quad_shuffle_up((vec<ushort, N>)value, delta);");
  			else
  				statement("return (vec<bool, N>)simd_shuffle_up((vec<ushort, N>)value, delta);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplSubgroupShuffleDown:
  			statement("template<typename T>");
  			statement("inline T spvSubgroupShuffleDown(T value, ushort delta)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return quad_shuffle_down(value, delta);");
  			else
  				statement("return simd_shuffle_down(value, delta);");
  			end_scope();
  			statement("");
  			statement("template<>");
  			statement("inline bool spvSubgroupShuffleDown(bool value, ushort delta)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return !!quad_shuffle_down((ushort)value, delta);");
  			else
  				statement("return !!simd_shuffle_down((ushort)value, delta);");
  			end_scope();
  			statement("");
  			statement("template<uint N>");
  			statement("inline vec<bool, N> spvSubgroupShuffleDown(vec<bool, N> value, ushort delta)");
  			begin_scope();
  			if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  				statement("return (vec<bool, N>)quad_shuffle_down((vec<ushort, N>)value, delta);");
  			else
  				statement("return (vec<bool, N>)simd_shuffle_down((vec<ushort, N>)value, delta);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplQuadBroadcast:
  			statement("template<typename T>");
  			statement("inline T spvQuadBroadcast(T value, uint lane)");
  			begin_scope();
  			statement("return quad_broadcast(value, lane);");
  			end_scope();
  			statement("");
  			statement("template<>");
  			statement("inline bool spvQuadBroadcast(bool value, uint lane)");
  			begin_scope();
  			statement("return !!quad_broadcast((ushort)value, lane);");
  			end_scope();
  			statement("");
  			statement("template<uint N>");
  			statement("inline vec<bool, N> spvQuadBroadcast(vec<bool, N> value, uint lane)");
  			begin_scope();
  			statement("return (vec<bool, N>)quad_broadcast((vec<ushort, N>)value, lane);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplQuadSwap:
  			// We can implement this easily based on the following table giving
  			// the target lane ID from the direction and current lane ID:
  			//        Direction
  			//      | 0 | 1 | 2 |
  			//   ---+---+---+---+
  			// L 0  | 1   2   3
  			// a 1  | 0   3   2
  			// n 2  | 3   0   1
  			// e 3  | 2   1   0
  			// Notice that target = source ^ (direction + 1).
  			statement("template<typename T>");
  			statement("inline T spvQuadSwap(T value, uint dir)");
  			begin_scope();
  			statement("return quad_shuffle_xor(value, dir + 1);");
  			end_scope();
  			statement("");
  			statement("template<>");
  			statement("inline bool spvQuadSwap(bool value, uint dir)");
  			begin_scope();
  			statement("return !!quad_shuffle_xor((ushort)value, dir + 1);");
  			end_scope();
  			statement("");
  			statement("template<uint N>");
  			statement("inline vec<bool, N> spvQuadSwap(vec<bool, N> value, uint dir)");
  			begin_scope();
  			statement("return (vec<bool, N>)quad_shuffle_xor((vec<ushort, N>)value, dir + 1);");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplReflectScalar:
  			// Metal does not support scalar versions of these functions.
  			statement("template<typename T>");
  			statement("inline T spvReflect(T i, T n)");
  			begin_scope();
  			statement("return i - T(2) * i * n * n;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplRefractScalar:
  			// Metal does not support scalar versions of these functions.
  			statement("template<typename T>");
  			statement("inline T spvRefract(T i, T n, T eta)");
  			begin_scope();
  			statement("T NoI = n * i;");
  			statement("T NoI2 = NoI * NoI;");
  			statement("T k = T(1) - eta * eta * (T(1) - NoI2);");
  			statement("if (k < T(0))");
  			begin_scope();
  			statement("return T(0);");
  			end_scope();
  			statement("else");
  			begin_scope();
  			statement("return eta * i - (eta * NoI + sqrt(k)) * n;");
  			end_scope();
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplFaceForwardScalar:
  			// Metal does not support scalar versions of these functions.
  			statement("template<typename T>");
  			statement("inline T spvFaceForward(T n, T i, T nref)");
  			begin_scope();
  			statement("return i * nref < T(0) ? n : -n;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplChromaReconstructNearest2Plane:
  			statement("template<typename T, typename... LodOptions>");
  			statement("inline vec<T, 4> spvChromaReconstructNearest(texture2d<T> plane0, texture2d<T> plane1, sampler "
  			          "samp, float2 coord, LodOptions... options)");
  			begin_scope();
  			statement("vec<T, 4> ycbcr = vec<T, 4>(0, 0, 0, 1);");
  			statement("ycbcr.g = plane0.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			statement("ycbcr.br = plane1.sample(samp, coord, spvForward<LodOptions>(options)...).rg;");
  			statement("return ycbcr;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplChromaReconstructNearest3Plane:
  			statement("template<typename T, typename... LodOptions>");
  			statement("inline vec<T, 4> spvChromaReconstructNearest(texture2d<T> plane0, texture2d<T> plane1, "
  			          "texture2d<T> plane2, sampler samp, float2 coord, LodOptions... options)");
  			begin_scope();
  			statement("vec<T, 4> ycbcr = vec<T, 4>(0, 0, 0, 1);");
  			statement("ycbcr.g = plane0.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			statement("ycbcr.b = plane1.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			statement("ycbcr.r = plane2.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			statement("return ycbcr;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplChromaReconstructLinear422CositedEven2Plane:
  			statement("template<typename T, typename... LodOptions>");
  			statement("inline vec<T, 4> spvChromaReconstructLinear422CositedEven(texture2d<T> plane0, texture2d<T> "
  			          "plane1, sampler samp, float2 coord, LodOptions... options)");
  			begin_scope();
  			statement("vec<T, 4> ycbcr = vec<T, 4>(0, 0, 0, 1);");
  			statement("ycbcr.g = plane0.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			statement("if (fract(coord.x * plane1.get_width()) != 0.0)");
  			begin_scope();
  			statement("ycbcr.br = vec<T, 2>(mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 0)), 0.5).rg);");
  			end_scope();
  			statement("else");
  			begin_scope();
  			statement("ycbcr.br = plane1.sample(samp, coord, spvForward<LodOptions>(options)...).rg;");
  			end_scope();
  			statement("return ycbcr;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplChromaReconstructLinear422CositedEven3Plane:
  			statement("template<typename T, typename... LodOptions>");
  			statement("inline vec<T, 4> spvChromaReconstructLinear422CositedEven(texture2d<T> plane0, texture2d<T> "
  			          "plane1, texture2d<T> plane2, sampler samp, float2 coord, LodOptions... options)");
  			begin_scope();
  			statement("vec<T, 4> ycbcr = vec<T, 4>(0, 0, 0, 1);");
  			statement("ycbcr.g = plane0.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			statement("if (fract(coord.x * plane1.get_width()) != 0.0)");
  			begin_scope();
  			statement("ycbcr.b = T(mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 0)), 0.5).r);");
  			statement("ycbcr.r = T(mix(plane2.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane2.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 0)), 0.5).r);");
  			end_scope();
  			statement("else");
  			begin_scope();
  			statement("ycbcr.b = plane1.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			statement("ycbcr.r = plane2.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			end_scope();
  			statement("return ycbcr;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplChromaReconstructLinear422Midpoint2Plane:
  			statement("template<typename T, typename... LodOptions>");
  			statement("inline vec<T, 4> spvChromaReconstructLinear422Midpoint(texture2d<T> plane0, texture2d<T> "
  			          "plane1, sampler samp, float2 coord, LodOptions... options)");
  			begin_scope();
  			statement("vec<T, 4> ycbcr = vec<T, 4>(0, 0, 0, 1);");
  			statement("ycbcr.g = plane0.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			statement("int2 offs = int2(fract(coord.x * plane1.get_width()) != 0.0 ? 1 : -1, 0);");
  			statement("ycbcr.br = vec<T, 2>(mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., offs), 0.25).rg);");
  			statement("return ycbcr;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplChromaReconstructLinear422Midpoint3Plane:
  			statement("template<typename T, typename... LodOptions>");
  			statement("inline vec<T, 4> spvChromaReconstructLinear422Midpoint(texture2d<T> plane0, texture2d<T> "
  			          "plane1, texture2d<T> plane2, sampler samp, float2 coord, LodOptions... options)");
  			begin_scope();
  			statement("vec<T, 4> ycbcr = vec<T, 4>(0, 0, 0, 1);");
  			statement("ycbcr.g = plane0.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			statement("int2 offs = int2(fract(coord.x * plane1.get_width()) != 0.0 ? 1 : -1, 0);");
  			statement("ycbcr.b = T(mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., offs), 0.25).r);");
  			statement("ycbcr.r = T(mix(plane2.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane2.sample(samp, coord, spvForward<LodOptions>(options)..., offs), 0.25).r);");
  			statement("return ycbcr;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplChromaReconstructLinear420XCositedEvenYCositedEven2Plane:
  			statement("template<typename T, typename... LodOptions>");
  			statement("inline vec<T, 4> spvChromaReconstructLinear420XCositedEvenYCositedEven(texture2d<T> plane0, "
  			          "texture2d<T> plane1, sampler samp, float2 coord, LodOptions... options)");
  			begin_scope();
  			statement("vec<T, 4> ycbcr = vec<T, 4>(0, 0, 0, 1);");
  			statement("ycbcr.g = plane0.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			statement("float2 ab = fract(round(coord * float2(plane0.get_width(), plane0.get_height())) * 0.5);");
  			statement("ycbcr.br = vec<T, 2>(mix(mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 0)), ab.x), "
  			          "mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(0, 1)), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 1)), ab.x), ab.y).rg);");
  			statement("return ycbcr;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplChromaReconstructLinear420XCositedEvenYCositedEven3Plane:
  			statement("template<typename T, typename... LodOptions>");
  			statement("inline vec<T, 4> spvChromaReconstructLinear420XCositedEvenYCositedEven(texture2d<T> plane0, "
  			          "texture2d<T> plane1, texture2d<T> plane2, sampler samp, float2 coord, LodOptions... options)");
  			begin_scope();
  			statement("vec<T, 4> ycbcr = vec<T, 4>(0, 0, 0, 1);");
  			statement("ycbcr.g = plane0.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			statement("float2 ab = fract(round(coord * float2(plane0.get_width(), plane0.get_height())) * 0.5);");
  			statement("ycbcr.b = T(mix(mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 0)), ab.x), "
  			          "mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(0, 1)), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 1)), ab.x), ab.y).r);");
  			statement("ycbcr.r = T(mix(mix(plane2.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane2.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 0)), ab.x), "
  			          "mix(plane2.sample(samp, coord, spvForward<LodOptions>(options)..., int2(0, 1)), "
  			          "plane2.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 1)), ab.x), ab.y).r);");
  			statement("return ycbcr;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplChromaReconstructLinear420XMidpointYCositedEven2Plane:
  			statement("template<typename T, typename... LodOptions>");
  			statement("inline vec<T, 4> spvChromaReconstructLinear420XMidpointYCositedEven(texture2d<T> plane0, "
  			          "texture2d<T> plane1, sampler samp, float2 coord, LodOptions... options)");
  			begin_scope();
  			statement("vec<T, 4> ycbcr = vec<T, 4>(0, 0, 0, 1);");
  			statement("ycbcr.g = plane0.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			statement("float2 ab = fract((round(coord * float2(plane0.get_width(), plane0.get_height())) - float2(0.5, "
  			          "0)) * 0.5);");
  			statement("ycbcr.br = vec<T, 2>(mix(mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 0)), ab.x), "
  			          "mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(0, 1)), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 1)), ab.x), ab.y).rg);");
  			statement("return ycbcr;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplChromaReconstructLinear420XMidpointYCositedEven3Plane:
  			statement("template<typename T, typename... LodOptions>");
  			statement("inline vec<T, 4> spvChromaReconstructLinear420XMidpointYCositedEven(texture2d<T> plane0, "
  			          "texture2d<T> plane1, texture2d<T> plane2, sampler samp, float2 coord, LodOptions... options)");
  			begin_scope();
  			statement("vec<T, 4> ycbcr = vec<T, 4>(0, 0, 0, 1);");
  			statement("ycbcr.g = plane0.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			statement("float2 ab = fract((round(coord * float2(plane0.get_width(), plane0.get_height())) - float2(0.5, "
  			          "0)) * 0.5);");
  			statement("ycbcr.b = T(mix(mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 0)), ab.x), "
  			          "mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(0, 1)), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 1)), ab.x), ab.y).r);");
  			statement("ycbcr.r = T(mix(mix(plane2.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane2.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 0)), ab.x), "
  			          "mix(plane2.sample(samp, coord, spvForward<LodOptions>(options)..., int2(0, 1)), "
  			          "plane2.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 1)), ab.x), ab.y).r);");
  			statement("return ycbcr;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplChromaReconstructLinear420XCositedEvenYMidpoint2Plane:
  			statement("template<typename T, typename... LodOptions>");
  			statement("inline vec<T, 4> spvChromaReconstructLinear420XCositedEvenYMidpoint(texture2d<T> plane0, "
  			          "texture2d<T> plane1, sampler samp, float2 coord, LodOptions... options)");
  			begin_scope();
  			statement("vec<T, 4> ycbcr = vec<T, 4>(0, 0, 0, 1);");
  			statement("ycbcr.g = plane0.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			statement("float2 ab = fract((round(coord * float2(plane0.get_width(), plane0.get_height())) - float2(0, "
  			          "0.5)) * 0.5);");
  			statement("ycbcr.br = vec<T, 2>(mix(mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 0)), ab.x), "
  			          "mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(0, 1)), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 1)), ab.x), ab.y).rg);");
  			statement("return ycbcr;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplChromaReconstructLinear420XCositedEvenYMidpoint3Plane:
  			statement("template<typename T, typename... LodOptions>");
  			statement("inline vec<T, 4> spvChromaReconstructLinear420XCositedEvenYMidpoint(texture2d<T> plane0, "
  			          "texture2d<T> plane1, texture2d<T> plane2, sampler samp, float2 coord, LodOptions... options)");
  			begin_scope();
  			statement("vec<T, 4> ycbcr = vec<T, 4>(0, 0, 0, 1);");
  			statement("ycbcr.g = plane0.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			statement("float2 ab = fract((round(coord * float2(plane0.get_width(), plane0.get_height())) - float2(0, "
  			          "0.5)) * 0.5);");
  			statement("ycbcr.b = T(mix(mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 0)), ab.x), "
  			          "mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(0, 1)), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 1)), ab.x), ab.y).r);");
  			statement("ycbcr.r = T(mix(mix(plane2.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane2.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 0)), ab.x), "
  			          "mix(plane2.sample(samp, coord, spvForward<LodOptions>(options)..., int2(0, 1)), "
  			          "plane2.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 1)), ab.x), ab.y).r);");
  			statement("return ycbcr;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplChromaReconstructLinear420XMidpointYMidpoint2Plane:
  			statement("template<typename T, typename... LodOptions>");
  			statement("inline vec<T, 4> spvChromaReconstructLinear420XMidpointYMidpoint(texture2d<T> plane0, "
  			          "texture2d<T> plane1, sampler samp, float2 coord, LodOptions... options)");
  			begin_scope();
  			statement("vec<T, 4> ycbcr = vec<T, 4>(0, 0, 0, 1);");
  			statement("ycbcr.g = plane0.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			statement("float2 ab = fract((round(coord * float2(plane0.get_width(), plane0.get_height())) - float2(0.5, "
  			          "0.5)) * 0.5);");
  			statement("ycbcr.br = vec<T, 2>(mix(mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 0)), ab.x), "
  			          "mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(0, 1)), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 1)), ab.x), ab.y).rg);");
  			statement("return ycbcr;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplChromaReconstructLinear420XMidpointYMidpoint3Plane:
  			statement("template<typename T, typename... LodOptions>");
  			statement("inline vec<T, 4> spvChromaReconstructLinear420XMidpointYMidpoint(texture2d<T> plane0, "
  			          "texture2d<T> plane1, texture2d<T> plane2, sampler samp, float2 coord, LodOptions... options)");
  			begin_scope();
  			statement("vec<T, 4> ycbcr = vec<T, 4>(0, 0, 0, 1);");
  			statement("ycbcr.g = plane0.sample(samp, coord, spvForward<LodOptions>(options)...).r;");
  			statement("float2 ab = fract((round(coord * float2(plane0.get_width(), plane0.get_height())) - float2(0.5, "
  			          "0.5)) * 0.5);");
  			statement("ycbcr.b = T(mix(mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 0)), ab.x), "
  			          "mix(plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(0, 1)), "
  			          "plane1.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 1)), ab.x), ab.y).r);");
  			statement("ycbcr.r = T(mix(mix(plane2.sample(samp, coord, spvForward<LodOptions>(options)...), "
  			          "plane2.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 0)), ab.x), "
  			          "mix(plane2.sample(samp, coord, spvForward<LodOptions>(options)..., int2(0, 1)), "
  			          "plane2.sample(samp, coord, spvForward<LodOptions>(options)..., int2(1, 1)), ab.x), ab.y).r);");
  			statement("return ycbcr;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplExpandITUFullRange:
  			statement("template<typename T>");
  			statement("inline vec<T, 4> spvExpandITUFullRange(vec<T, 4> ycbcr, int n)");
  			begin_scope();
  			statement("ycbcr.br -= exp2(T(n-1))/(exp2(T(n))-1);");
  			statement("return ycbcr;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplExpandITUNarrowRange:
  			statement("template<typename T>");
  			statement("inline vec<T, 4> spvExpandITUNarrowRange(vec<T, 4> ycbcr, int n)");
  			begin_scope();
  			statement("ycbcr.g = (ycbcr.g * (exp2(T(n)) - 1) - ldexp(T(16), n - 8))/ldexp(T(219), n - 8);");
  			statement("ycbcr.br = (ycbcr.br * (exp2(T(n)) - 1) - ldexp(T(128), n - 8))/ldexp(T(224), n - 8);");
  			statement("return ycbcr;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplConvertYCbCrBT709:
  			statement("// cf. Khronos Data Format Specification, section 15.1.1");
  			statement("constant float3x3 spvBT709Factors = {{1, 1, 1}, {0, -0.13397432/0.7152, 1.8556}, {1.5748, "
  			          "-0.33480248/0.7152, 0}};");
  			statement("");
  			statement("template<typename T>");
  			statement("inline vec<T, 4> spvConvertYCbCrBT709(vec<T, 4> ycbcr)");
  			begin_scope();
  			statement("vec<T, 4> rgba;");
  			statement("rgba.rgb = vec<T, 3>(spvBT709Factors * ycbcr.gbr);");
  			statement("rgba.a = ycbcr.a;");
  			statement("return rgba;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplConvertYCbCrBT601:
  			statement("// cf. Khronos Data Format Specification, section 15.1.2");
  			statement("constant float3x3 spvBT601Factors = {{1, 1, 1}, {0, -0.202008/0.587, 1.772}, {1.402, "
  			          "-0.419198/0.587, 0}};");
  			statement("");
  			statement("template<typename T>");
  			statement("inline vec<T, 4> spvConvertYCbCrBT601(vec<T, 4> ycbcr)");
  			begin_scope();
  			statement("vec<T, 4> rgba;");
  			statement("rgba.rgb = vec<T, 3>(spvBT601Factors * ycbcr.gbr);");
  			statement("rgba.a = ycbcr.a;");
  			statement("return rgba;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplConvertYCbCrBT2020:
  			statement("// cf. Khronos Data Format Specification, section 15.1.3");
  			statement("constant float3x3 spvBT2020Factors = {{1, 1, 1}, {0, -0.11156702/0.6780, 1.8814}, {1.4746, "
  			          "-0.38737742/0.6780, 0}};");
  			statement("");
  			statement("template<typename T>");
  			statement("inline vec<T, 4> spvConvertYCbCrBT2020(vec<T, 4> ycbcr)");
  			begin_scope();
  			statement("vec<T, 4> rgba;");
  			statement("rgba.rgb = vec<T, 3>(spvBT2020Factors * ycbcr.gbr);");
  			statement("rgba.a = ycbcr.a;");
  			statement("return rgba;");
  			end_scope();
  			statement("");
  			break;
  
  		case SPVFuncImplDynamicImageSampler:
  			statement("enum class spvFormatResolution");
  			begin_scope();
  			statement("_444 = 0,");
  			statement("_422,");
  			statement("_420");
  			end_scope_decl();
  			statement("");
  			statement("enum class spvChromaFilter");
  			begin_scope();
  			statement("nearest = 0,");
  			statement("linear");
  			end_scope_decl();
  			statement("");
  			statement("enum class spvXChromaLocation");
  			begin_scope();
  			statement("cosited_even = 0,");
  			statement("midpoint");
  			end_scope_decl();
  			statement("");
  			statement("enum class spvYChromaLocation");
  			begin_scope();
  			statement("cosited_even = 0,");
  			statement("midpoint");
  			end_scope_decl();
  			statement("");
  			statement("enum class spvYCbCrModelConversion");
  			begin_scope();
  			statement("rgb_identity = 0,");
  			statement("ycbcr_identity,");
  			statement("ycbcr_bt_709,");
  			statement("ycbcr_bt_601,");
  			statement("ycbcr_bt_2020");
  			end_scope_decl();
  			statement("");
  			statement("enum class spvYCbCrRange");
  			begin_scope();
  			statement("itu_full = 0,");
  			statement("itu_narrow");
  			end_scope_decl();
  			statement("");
  			statement("struct spvComponentBits");
  			begin_scope();
  			statement("constexpr explicit spvComponentBits(int v) thread : value(v) {}");
  			statement("uchar value : 6;");
  			end_scope_decl();
  			statement("// A class corresponding to metal::sampler which holds sampler");
  			statement("// Y'CbCr conversion info.");
  			statement("struct spvYCbCrSampler");
  			begin_scope();
  			statement("constexpr spvYCbCrSampler() thread : val(build()) {}");
  			statement("template<typename... Ts>");
  			statement("constexpr spvYCbCrSampler(Ts... t) thread : val(build(t...)) {}");
  			statement("constexpr spvYCbCrSampler(const thread spvYCbCrSampler& s) thread = default;");
  			statement("");
  			statement("spvFormatResolution get_resolution() const thread");
  			begin_scope();
  			statement("return spvFormatResolution((val & resolution_mask) >> resolution_base);");
  			end_scope();
  			statement("spvChromaFilter get_chroma_filter() const thread");
  			begin_scope();
  			statement("return spvChromaFilter((val & chroma_filter_mask) >> chroma_filter_base);");
  			end_scope();
  			statement("spvXChromaLocation get_x_chroma_offset() const thread");
  			begin_scope();
  			statement("return spvXChromaLocation((val & x_chroma_off_mask) >> x_chroma_off_base);");
  			end_scope();
  			statement("spvYChromaLocation get_y_chroma_offset() const thread");
  			begin_scope();
  			statement("return spvYChromaLocation((val & y_chroma_off_mask) >> y_chroma_off_base);");
  			end_scope();
  			statement("spvYCbCrModelConversion get_ycbcr_model() const thread");
  			begin_scope();
  			statement("return spvYCbCrModelConversion((val & ycbcr_model_mask) >> ycbcr_model_base);");
  			end_scope();
  			statement("spvYCbCrRange get_ycbcr_range() const thread");
  			begin_scope();
  			statement("return spvYCbCrRange((val & ycbcr_range_mask) >> ycbcr_range_base);");
  			end_scope();
  			statement("int get_bpc() const thread { return (val & bpc_mask) >> bpc_base; }");
  			statement("");
  			statement("private:");
  			statement("ushort val;");
  			statement("");
  			statement("constexpr static constant ushort resolution_bits = 2;");
  			statement("constexpr static constant ushort chroma_filter_bits = 2;");
  			statement("constexpr static constant ushort x_chroma_off_bit = 1;");
  			statement("constexpr static constant ushort y_chroma_off_bit = 1;");
  			statement("constexpr static constant ushort ycbcr_model_bits = 3;");
  			statement("constexpr static constant ushort ycbcr_range_bit = 1;");
  			statement("constexpr static constant ushort bpc_bits = 6;");
  			statement("");
  			statement("constexpr static constant ushort resolution_base = 0;");
  			statement("constexpr static constant ushort chroma_filter_base = 2;");
  			statement("constexpr static constant ushort x_chroma_off_base = 4;");
  			statement("constexpr static constant ushort y_chroma_off_base = 5;");
  			statement("constexpr static constant ushort ycbcr_model_base = 6;");
  			statement("constexpr static constant ushort ycbcr_range_base = 9;");
  			statement("constexpr static constant ushort bpc_base = 10;");
  			statement("");
  			statement(
  			    "constexpr static constant ushort resolution_mask = ((1 << resolution_bits) - 1) << resolution_base;");
  			statement("constexpr static constant ushort chroma_filter_mask = ((1 << chroma_filter_bits) - 1) << "
  			          "chroma_filter_base;");
  			statement("constexpr static constant ushort x_chroma_off_mask = ((1 << x_chroma_off_bit) - 1) << "
  			          "x_chroma_off_base;");
  			statement("constexpr static constant ushort y_chroma_off_mask = ((1 << y_chroma_off_bit) - 1) << "
  			          "y_chroma_off_base;");
  			statement("constexpr static constant ushort ycbcr_model_mask = ((1 << ycbcr_model_bits) - 1) << "
  			          "ycbcr_model_base;");
  			statement("constexpr static constant ushort ycbcr_range_mask = ((1 << ycbcr_range_bit) - 1) << "
  			          "ycbcr_range_base;");
  			statement("constexpr static constant ushort bpc_mask = ((1 << bpc_bits) - 1) << bpc_base;");
  			statement("");
  			statement("static constexpr ushort build()");
  			begin_scope();
  			statement("return 0;");
  			end_scope();
  			statement("");
  			statement("template<typename... Ts>");
  			statement("static constexpr ushort build(spvFormatResolution res, Ts... t)");
  			begin_scope();
  			statement("return (ushort(res) << resolution_base) | (build(t...) & ~resolution_mask);");
  			end_scope();
  			statement("");
  			statement("template<typename... Ts>");
  			statement("static constexpr ushort build(spvChromaFilter filt, Ts... t)");
  			begin_scope();
  			statement("return (ushort(filt) << chroma_filter_base) | (build(t...) & ~chroma_filter_mask);");
  			end_scope();
  			statement("");
  			statement("template<typename... Ts>");
  			statement("static constexpr ushort build(spvXChromaLocation loc, Ts... t)");
  			begin_scope();
  			statement("return (ushort(loc) << x_chroma_off_base) | (build(t...) & ~x_chroma_off_mask);");
  			end_scope();
  			statement("");
  			statement("template<typename... Ts>");
  			statement("static constexpr ushort build(spvYChromaLocation loc, Ts... t)");
  			begin_scope();
  			statement("return (ushort(loc) << y_chroma_off_base) | (build(t...) & ~y_chroma_off_mask);");
  			end_scope();
  			statement("");
  			statement("template<typename... Ts>");
  			statement("static constexpr ushort build(spvYCbCrModelConversion model, Ts... t)");
  			begin_scope();
  			statement("return (ushort(model) << ycbcr_model_base) | (build(t...) & ~ycbcr_model_mask);");
  			end_scope();
  			statement("");
  			statement("template<typename... Ts>");
  			statement("static constexpr ushort build(spvYCbCrRange range, Ts... t)");
  			begin_scope();
  			statement("return (ushort(range) << ycbcr_range_base) | (build(t...) & ~ycbcr_range_mask);");
  			end_scope();
  			statement("");
  			statement("template<typename... Ts>");
  			statement("static constexpr ushort build(spvComponentBits bpc, Ts... t)");
  			begin_scope();
  			statement("return (ushort(bpc.value) << bpc_base) | (build(t...) & ~bpc_mask);");
  			end_scope();
  			end_scope_decl();
  			statement("");
  			statement("// A class which can hold up to three textures and a sampler, including");
  			statement("// Y'CbCr conversion info, used to pass combined image-samplers");
  			statement("// dynamically to functions.");
  			statement("template<typename T>");
  			statement("struct spvDynamicImageSampler");
  			begin_scope();
  			statement("texture2d<T> plane0;");
  			statement("texture2d<T> plane1;");
  			statement("texture2d<T> plane2;");
  			statement("sampler samp;");
  			statement("spvYCbCrSampler ycbcr_samp;");
  			statement("uint swizzle = 0;");
  			statement("");
  			if (msl_options.swizzle_texture_samples)
  			{
  				statement("constexpr spvDynamicImageSampler(texture2d<T> tex, sampler samp, uint sw) thread :");
  				statement("    plane0(tex), samp(samp), swizzle(sw) {}");
  			}
  			else
  			{
  				statement("constexpr spvDynamicImageSampler(texture2d<T> tex, sampler samp) thread :");
  				statement("    plane0(tex), samp(samp) {}");
  			}
  			statement("constexpr spvDynamicImageSampler(texture2d<T> tex, sampler samp, spvYCbCrSampler ycbcr_samp, "
  			          "uint sw) thread :");
  			statement("    plane0(tex), samp(samp), ycbcr_samp(ycbcr_samp), swizzle(sw) {}");
  			statement("constexpr spvDynamicImageSampler(texture2d<T> plane0, texture2d<T> plane1,");
  			statement("                                 sampler samp, spvYCbCrSampler ycbcr_samp, uint sw) thread :");
  			statement("    plane0(plane0), plane1(plane1), samp(samp), ycbcr_samp(ycbcr_samp), swizzle(sw) {}");
  			statement(
  			    "constexpr spvDynamicImageSampler(texture2d<T> plane0, texture2d<T> plane1, texture2d<T> plane2,");
  			statement("                                 sampler samp, spvYCbCrSampler ycbcr_samp, uint sw) thread :");
  			statement("    plane0(plane0), plane1(plane1), plane2(plane2), samp(samp), ycbcr_samp(ycbcr_samp), "
  			          "swizzle(sw) {}");
  			statement("");
  			// XXX This is really hard to follow... I've left comments to make it a bit easier.
  			statement("template<typename... LodOptions>");
  			statement("vec<T, 4> do_sample(float2 coord, LodOptions... options) const thread");
  			begin_scope();
  			statement("if (!is_null_texture(plane1))");
  			begin_scope();
  			statement("if (ycbcr_samp.get_resolution() == spvFormatResolution::_444 ||");
  			statement("    ycbcr_samp.get_chroma_filter() == spvChromaFilter::nearest)");
  			begin_scope();
  			statement("if (!is_null_texture(plane2))");
  			statement("    return spvChromaReconstructNearest(plane0, plane1, plane2, samp, coord,");
  			statement("                                       spvForward<LodOptions>(options)...);");
  			statement(
  			    "return spvChromaReconstructNearest(plane0, plane1, samp, coord, spvForward<LodOptions>(options)...);");
  			end_scope(); // if (resolution == 422 || chroma_filter == nearest)
  			statement("switch (ycbcr_samp.get_resolution())");
  			begin_scope();
  			statement("case spvFormatResolution::_444: break;");
  			statement("case spvFormatResolution::_422:");
  			begin_scope();
  			statement("switch (ycbcr_samp.get_x_chroma_offset())");
  			begin_scope();
  			statement("case spvXChromaLocation::cosited_even:");
  			statement("    if (!is_null_texture(plane2))");
  			statement("        return spvChromaReconstructLinear422CositedEven(");
  			statement("            plane0, plane1, plane2, samp,");
  			statement("            coord, spvForward<LodOptions>(options)...);");
  			statement("    return spvChromaReconstructLinear422CositedEven(");
  			statement("        plane0, plane1, samp, coord,");
  			statement("        spvForward<LodOptions>(options)...);");
  			statement("case spvXChromaLocation::midpoint:");
  			statement("    if (!is_null_texture(plane2))");
  			statement("        return spvChromaReconstructLinear422Midpoint(");
  			statement("            plane0, plane1, plane2, samp,");
  			statement("            coord, spvForward<LodOptions>(options)...);");
  			statement("    return spvChromaReconstructLinear422Midpoint(");
  			statement("        plane0, plane1, samp, coord,");
  			statement("        spvForward<LodOptions>(options)...);");
  			end_scope(); // switch (x_chroma_offset)
  			end_scope(); // case 422:
  			statement("case spvFormatResolution::_420:");
  			begin_scope();
  			statement("switch (ycbcr_samp.get_x_chroma_offset())");
  			begin_scope();
  			statement("case spvXChromaLocation::cosited_even:");
  			begin_scope();
  			statement("switch (ycbcr_samp.get_y_chroma_offset())");
  			begin_scope();
  			statement("case spvYChromaLocation::cosited_even:");
  			statement("    if (!is_null_texture(plane2))");
  			statement("        return spvChromaReconstructLinear420XCositedEvenYCositedEven(");
  			statement("            plane0, plane1, plane2, samp,");
  			statement("            coord, spvForward<LodOptions>(options)...);");
  			statement("    return spvChromaReconstructLinear420XCositedEvenYCositedEven(");
  			statement("        plane0, plane1, samp, coord,");
  			statement("        spvForward<LodOptions>(options)...);");
  			statement("case spvYChromaLocation::midpoint:");
  			statement("    if (!is_null_texture(plane2))");
  			statement("        return spvChromaReconstructLinear420XCositedEvenYMidpoint(");
  			statement("            plane0, plane1, plane2, samp,");
  			statement("            coord, spvForward<LodOptions>(options)...);");
  			statement("    return spvChromaReconstructLinear420XCositedEvenYMidpoint(");
  			statement("        plane0, plane1, samp, coord,");
  			statement("        spvForward<LodOptions>(options)...);");
  			end_scope(); // switch (y_chroma_offset)
  			end_scope(); // case x::cosited_even:
  			statement("case spvXChromaLocation::midpoint:");
  			begin_scope();
  			statement("switch (ycbcr_samp.get_y_chroma_offset())");
  			begin_scope();
  			statement("case spvYChromaLocation::cosited_even:");
  			statement("    if (!is_null_texture(plane2))");
  			statement("        return spvChromaReconstructLinear420XMidpointYCositedEven(");
  			statement("            plane0, plane1, plane2, samp,");
  			statement("            coord, spvForward<LodOptions>(options)...);");
  			statement("    return spvChromaReconstructLinear420XMidpointYCositedEven(");
  			statement("        plane0, plane1, samp, coord,");
  			statement("        spvForward<LodOptions>(options)...);");
  			statement("case spvYChromaLocation::midpoint:");
  			statement("    if (!is_null_texture(plane2))");
  			statement("        return spvChromaReconstructLinear420XMidpointYMidpoint(");
  			statement("            plane0, plane1, plane2, samp,");
  			statement("            coord, spvForward<LodOptions>(options)...);");
  			statement("    return spvChromaReconstructLinear420XMidpointYMidpoint(");
  			statement("        plane0, plane1, samp, coord,");
  			statement("        spvForward<LodOptions>(options)...);");
  			end_scope(); // switch (y_chroma_offset)
  			end_scope(); // case x::midpoint
  			end_scope(); // switch (x_chroma_offset)
  			end_scope(); // case 420:
  			end_scope(); // switch (resolution)
  			end_scope(); // if (multiplanar)
  			statement("return plane0.sample(samp, coord, spvForward<LodOptions>(options)...);");
  			end_scope(); // do_sample()
  			statement("template <typename... LodOptions>");
  			statement("vec<T, 4> sample(float2 coord, LodOptions... options) const thread");
  			begin_scope();
  			statement(
  			    "vec<T, 4> s = spvTextureSwizzle(do_sample(coord, spvForward<LodOptions>(options)...), swizzle);");
  			statement("if (ycbcr_samp.get_ycbcr_model() == spvYCbCrModelConversion::rgb_identity)");
  			statement("    return s;");
  			statement("");
  			statement("switch (ycbcr_samp.get_ycbcr_range())");
  			begin_scope();
  			statement("case spvYCbCrRange::itu_full:");
  			statement("    s = spvExpandITUFullRange(s, ycbcr_samp.get_bpc());");
  			statement("    break;");
  			statement("case spvYCbCrRange::itu_narrow:");
  			statement("    s = spvExpandITUNarrowRange(s, ycbcr_samp.get_bpc());");
  			statement("    break;");
  			end_scope();
  			statement("");
  			statement("switch (ycbcr_samp.get_ycbcr_model())");
  			begin_scope();
  			statement("case spvYCbCrModelConversion::rgb_identity:"); // Silence Clang warning
  			statement("case spvYCbCrModelConversion::ycbcr_identity:");
  			statement("    return s;");
  			statement("case spvYCbCrModelConversion::ycbcr_bt_709:");
  			statement("    return spvConvertYCbCrBT709(s);");
  			statement("case spvYCbCrModelConversion::ycbcr_bt_601:");
  			statement("    return spvConvertYCbCrBT601(s);");
  			statement("case spvYCbCrModelConversion::ycbcr_bt_2020:");
  			statement("    return spvConvertYCbCrBT2020(s);");
  			end_scope();
  			end_scope();
  			statement("");
  			// Sampler Y'CbCr conversion forbids offsets.
  			statement("vec<T, 4> sample(float2 coord, int2 offset) const thread");
  			begin_scope();
  			if (msl_options.swizzle_texture_samples)
  				statement("return spvTextureSwizzle(plane0.sample(samp, coord, offset), swizzle);");
  			else
  				statement("return plane0.sample(samp, coord, offset);");
  			end_scope();
  			statement("template<typename lod_options>");
  			statement("vec<T, 4> sample(float2 coord, lod_options options, int2 offset) const thread");
  			begin_scope();
  			if (msl_options.swizzle_texture_samples)
  				statement("return spvTextureSwizzle(plane0.sample(samp, coord, options, offset), swizzle);");
  			else
  				statement("return plane0.sample(samp, coord, options, offset);");
  			end_scope();
  			statement("#if __HAVE_MIN_LOD_CLAMP__");
  			statement("vec<T, 4> sample(float2 coord, bias b, min_lod_clamp min_lod, int2 offset) const thread");
  			begin_scope();
  			statement("return plane0.sample(samp, coord, b, min_lod, offset);");
  			end_scope();
  			statement(
  			    "vec<T, 4> sample(float2 coord, gradient2d grad, min_lod_clamp min_lod, int2 offset) const thread");
  			begin_scope();
  			statement("return plane0.sample(samp, coord, grad, min_lod, offset);");
  			end_scope();
  			statement("#endif");
  			statement("");
  			// Y'CbCr conversion forbids all operations but sampling.
  			statement("vec<T, 4> read(uint2 coord, uint lod = 0) const thread");
  			begin_scope();
  			statement("return plane0.read(coord, lod);");
  			end_scope();
  			statement("");
  			statement("vec<T, 4> gather(float2 coord, int2 offset = int2(0), component c = component::x) const thread");
  			begin_scope();
  			if (msl_options.swizzle_texture_samples)
  				statement("return spvGatherSwizzle(plane0, samp, swizzle, c, coord, offset);");
  			else
  				statement("return plane0.gather(samp, coord, offset, c);");
  			end_scope();
  			end_scope_decl();
  			statement("");
  
  		default:
  			break;
  		}
  	}
  }
  
  static string inject_top_level_storage_qualifier(const string &expr, const string &qualifier)
  {
  	// Easier to do this through text munging since the qualifier does not exist in the type system at all,
  	// and plumbing in all that information is not very helpful.
  	size_t last_reference = expr.find_last_of('&');
  	size_t last_pointer = expr.find_last_of('*');
  	size_t last_significant = string::npos;
  
  	if (last_reference == string::npos)
  		last_significant = last_pointer;
  	else if (last_pointer == string::npos)
  		last_significant = last_reference;
  	else
  		last_significant = std::max(last_reference, last_pointer);
  
  	if (last_significant == string::npos)
  		return join(qualifier, " ", expr);
  	else
  	{
  		return join(expr.substr(0, last_significant + 1), " ",
  		            qualifier, expr.substr(last_significant + 1, string::npos));
  	}
  }
  
  // Undefined global memory is not allowed in MSL.
  // Declare constant and init to zeros. Use {}, as global constructors can break Metal.
  void CompilerMSL::declare_undefined_values()
  {
  	bool emitted = false;
  	ir.for_each_typed_id<SPIRUndef>([&](uint32_t, SPIRUndef &undef) {
  		auto &type = this->get<SPIRType>(undef.basetype);
  		// OpUndef can be void for some reason ...
  		if (type.basetype == SPIRType::Void)
  			return;
  
  		statement(inject_top_level_storage_qualifier(
  				variable_decl(type, to_name(undef.self), undef.self),
  				"constant"),
  		          " = {};");
  		emitted = true;
  	});
  
  	if (emitted)
  		statement("");
  }
  
  void CompilerMSL::declare_constant_arrays()
  {
  	bool fully_inlined = ir.ids_for_type[TypeFunction].size() == 1;
  
  	// MSL cannot declare arrays inline (except when declaring a variable), so we must move them out to
  	// global constants directly, so we are able to use constants as variable expressions.
  	bool emitted = false;
  
  	ir.for_each_typed_id<SPIRConstant>([&](uint32_t, SPIRConstant &c) {
  		if (c.specialization)
  			return;
  
  		auto &type = this->get<SPIRType>(c.constant_type);
  		// Constant arrays of non-primitive types (i.e. matrices) won't link properly into Metal libraries.
  		// FIXME: However, hoisting constants to main() means we need to pass down constant arrays to leaf functions if they are used there.
  		// If there are multiple functions in the module, drop this case to avoid breaking use cases which do not need to
  		// link into Metal libraries. This is hacky.
  		if (!type.array.empty() && (!fully_inlined || is_scalar(type) || is_vector(type)))
  		{
  			auto name = to_name(c.self);
  			statement(inject_top_level_storage_qualifier(variable_decl(type, name), "constant"),
  			          " = ", constant_expression(c), ";");
  			emitted = true;
  		}
  	});
  
  	if (emitted)
  		statement("");
  }
  
  // Constant arrays of non-primitive types (i.e. matrices) won't link properly into Metal libraries
  void CompilerMSL::declare_complex_constant_arrays()
  {
  	// If we do not have a fully inlined module, we did not opt in to
  	// declaring constant arrays of complex types. See CompilerMSL::declare_constant_arrays().
  	bool fully_inlined = ir.ids_for_type[TypeFunction].size() == 1;
  	if (!fully_inlined)
  		return;
  
  	// MSL cannot declare arrays inline (except when declaring a variable), so we must move them out to
  	// global constants directly, so we are able to use constants as variable expressions.
  	bool emitted = false;
  
  	ir.for_each_typed_id<SPIRConstant>([&](uint32_t, SPIRConstant &c) {
  		if (c.specialization)
  			return;
  
  		auto &type = this->get<SPIRType>(c.constant_type);
  		if (!type.array.empty() && !(is_scalar(type) || is_vector(type)))
  		{
  			auto name = to_name(c.self);
  			statement("", variable_decl(type, name), " = ", constant_expression(c), ";");
  			emitted = true;
  		}
  	});
  
  	if (emitted)
  		statement("");
  }
  
  void CompilerMSL::emit_resources()
  {
  	declare_constant_arrays();
  	declare_undefined_values();
  
  	// Emit the special [[stage_in]] and [[stage_out]] interface blocks which we created.
  	emit_interface_block(stage_out_var_id);
  	emit_interface_block(patch_stage_out_var_id);
  	emit_interface_block(stage_in_var_id);
  	emit_interface_block(patch_stage_in_var_id);
  }
  
  // Emit declarations for the specialization Metal function constants
  void CompilerMSL::emit_specialization_constants_and_structs()
  {
  	SpecializationConstant wg_x, wg_y, wg_z;
  	ID workgroup_size_id = get_work_group_size_specialization_constants(wg_x, wg_y, wg_z);
  	bool emitted = false;
  
  	unordered_set<uint32_t> declared_structs;
  	unordered_set<uint32_t> aligned_structs;
  
  	// First, we need to deal with scalar block layout.
  	// It is possible that a struct may have to be placed at an alignment which does not match the innate alignment of the struct itself.
  	// In that case, if such a case exists for a struct, we must force that all elements of the struct become packed_ types.
  	// This makes the struct alignment as small as physically possible.
  	// When we actually align the struct later, we can insert padding as necessary to make the packed members behave like normally aligned types.
  	ir.for_each_typed_id<SPIRType>([&](uint32_t type_id, const SPIRType &type) {
  		if (type.basetype == SPIRType::Struct &&
  		    has_extended_decoration(type_id, SPIRVCrossDecorationBufferBlockRepacked))
  			mark_scalar_layout_structs(type);
  	});
  
  	bool builtin_block_type_is_required = false;
  	// Very special case. If gl_PerVertex is initialized as an array (tessellation)
  	// we have to potentially emit the gl_PerVertex struct type so that we can emit a constant LUT.
  	ir.for_each_typed_id<SPIRConstant>([&](uint32_t, SPIRConstant &c) {
  		auto &type = this->get<SPIRType>(c.constant_type);
  		if (is_array(type) && has_decoration(type.self, DecorationBlock) && is_builtin_type(type))
  			builtin_block_type_is_required = true;
  	});
  
  	// Very particular use of the soft loop lock.
  	// align_struct may need to create custom types on the fly, but we don't care about
  	// these types for purpose of iterating over them in ir.ids_for_type and friends.
  	auto loop_lock = ir.create_loop_soft_lock();
  
  	for (auto &id_ : ir.ids_for_constant_or_type)
  	{
  		auto &id = ir.ids[id_];
  
  		if (id.get_type() == TypeConstant)
  		{
  			auto &c = id.get<SPIRConstant>();
  
  			if (c.self == workgroup_size_id)
  			{
  				// TODO: This can be expressed as a [[threads_per_threadgroup]] input semantic, but we need to know
  				// the work group size at compile time in SPIR-V, and [[threads_per_threadgroup]] would need to be passed around as a global.
  				// The work group size may be a specialization constant.
  				statement("constant uint3 ", builtin_to_glsl(BuiltInWorkgroupSize, StorageClassWorkgroup),
  				          " [[maybe_unused]] = ", constant_expression(get<SPIRConstant>(workgroup_size_id)), ";");
  				emitted = true;
  			}
  			else if (c.specialization)
  			{
  				auto &type = get<SPIRType>(c.constant_type);
  				string sc_type_name = type_to_glsl(type);
  				string sc_name = to_name(c.self);
  				string sc_tmp_name = sc_name + "_tmp";
  
  				// Function constants are only supported in MSL 1.2 and later.
  				// If we don't support it just declare the "default" directly.
  				// This "default" value can be overridden to the true specialization constant by the API user.
  				// Specialization constants which are used as array length expressions cannot be function constants in MSL,
  				// so just fall back to macros.
  				if (msl_options.supports_msl_version(1, 2) && has_decoration(c.self, DecorationSpecId) &&
  				    !c.is_used_as_array_length)
  				{
  					uint32_t constant_id = get_decoration(c.self, DecorationSpecId);
  					// Only scalar, non-composite values can be function constants.
  					statement("constant ", sc_type_name, " ", sc_tmp_name, " [[function_constant(", constant_id,
  					          ")]];");
  					statement("constant ", sc_type_name, " ", sc_name, " = is_function_constant_defined(", sc_tmp_name,
  					          ") ? ", sc_tmp_name, " : ", constant_expression(c), ";");
  				}
  				else if (has_decoration(c.self, DecorationSpecId))
  				{
  					// Fallback to macro overrides.
  					c.specialization_constant_macro_name =
  					    constant_value_macro_name(get_decoration(c.self, DecorationSpecId));
  
  					statement("#ifndef ", c.specialization_constant_macro_name);
  					statement("#define ", c.specialization_constant_macro_name, " ", constant_expression(c));
  					statement("#endif");
  					statement("constant ", sc_type_name, " ", sc_name, " = ", c.specialization_constant_macro_name,
  					          ";");
  				}
  				else
  				{
  					// Composite specialization constants must be built from other specialization constants.
  					statement("constant ", sc_type_name, " ", sc_name, " = ", constant_expression(c), ";");
  				}
  				emitted = true;
  			}
  		}
  		else if (id.get_type() == TypeConstantOp)
  		{
  			auto &c = id.get<SPIRConstantOp>();
  			auto &type = get<SPIRType>(c.basetype);
  			auto name = to_name(c.self);
  			statement("constant ", variable_decl(type, name), " = ", constant_op_expression(c), ";");
  			emitted = true;
  		}
  		else if (id.get_type() == TypeType)
  		{
  			// Output non-builtin interface structs. These include local function structs
  			// and structs nested within uniform and read-write buffers.
  			auto &type = id.get<SPIRType>();
  			TypeID type_id = type.self;
  
  			bool is_struct = (type.basetype == SPIRType::Struct) && type.array.empty() && !type.pointer;
  			bool is_block =
  			    has_decoration(type.self, DecorationBlock) || has_decoration(type.self, DecorationBufferBlock);
  
  			bool is_builtin_block = is_block && is_builtin_type(type);
  			bool is_declarable_struct = is_struct && (!is_builtin_block || builtin_block_type_is_required);
  
  			// We'll declare this later.
  			if (stage_out_var_id && get_stage_out_struct_type().self == type_id)
  				is_declarable_struct = false;
  			if (patch_stage_out_var_id && get_patch_stage_out_struct_type().self == type_id)
  				is_declarable_struct = false;
  			if (stage_in_var_id && get_stage_in_struct_type().self == type_id)
  				is_declarable_struct = false;
  			if (patch_stage_in_var_id && get_patch_stage_in_struct_type().self == type_id)
  				is_declarable_struct = false;
  
  			// Special case. Declare builtin struct anyways if we need to emit a threadgroup version of it.
  			if (stage_out_masked_builtin_type_id == type_id)
  				is_declarable_struct = true;
  
  			// Align and emit declarable structs...but avoid declaring each more than once.
  			if (is_declarable_struct && declared_structs.count(type_id) == 0)
  			{
  				if (emitted)
  					statement("");
  				emitted = false;
  
  				declared_structs.insert(type_id);
  
  				if (has_extended_decoration(type_id, SPIRVCrossDecorationBufferBlockRepacked))
  					align_struct(type, aligned_structs);
  
  				// Make sure we declare the underlying struct type, and not the "decorated" type with pointers, etc.
  				emit_struct(get<SPIRType>(type_id));
  			}
  		}
  	}
  
  	if (emitted)
  		statement("");
  }
  
  void CompilerMSL::emit_binary_unord_op(uint32_t result_type, uint32_t result_id, uint32_t op0, uint32_t op1,
                                         const char *op)
  {
  	bool forward = should_forward(op0) && should_forward(op1);
  	emit_op(result_type, result_id,
  	        join("(isunordered(", to_enclosed_unpacked_expression(op0), ", ", to_enclosed_unpacked_expression(op1),
  	             ") || ", to_enclosed_unpacked_expression(op0), " ", op, " ", to_enclosed_unpacked_expression(op1),
  	             ")"),
  	        forward);
  
  	inherit_expression_dependencies(result_id, op0);
  	inherit_expression_dependencies(result_id, op1);
  }
  
  bool CompilerMSL::emit_tessellation_io_load(uint32_t result_type_id, uint32_t id, uint32_t ptr)
  {
  	auto &ptr_type = expression_type(ptr);
  	auto &result_type = get<SPIRType>(result_type_id);
  	if (ptr_type.storage != StorageClassInput && ptr_type.storage != StorageClassOutput)
  		return false;
  	if (ptr_type.storage == StorageClassOutput && get_execution_model() == ExecutionModelTessellationEvaluation)
  		return false;
  
  	if (has_decoration(ptr, DecorationPatch))
  		return false;
  	bool ptr_is_io_variable = ir.ids[ptr].get_type() == TypeVariable;
  
  	bool flattened_io = variable_storage_requires_stage_io(ptr_type.storage);
  
  	bool flat_data_type = flattened_io &&
  	                      (is_matrix(result_type) || is_array(result_type) || result_type.basetype == SPIRType::Struct);
  
  	// Edge case, even with multi-patch workgroups, we still need to unroll load
  	// if we're loading control points directly.
  	if (ptr_is_io_variable && is_array(result_type))
  		flat_data_type = true;
  
  	if (!flat_data_type)
  		return false;
  
  	// Now, we must unflatten a composite type and take care of interleaving array access with gl_in/gl_out.
  	// Lots of painful code duplication since we *really* should not unroll these kinds of loads in entry point fixup
  	// unless we're forced to do this when the code is emitting inoptimal OpLoads.
  	string expr;
  
  	uint32_t interface_index = get_extended_decoration(ptr, SPIRVCrossDecorationInterfaceMemberIndex);
  	auto *var = maybe_get_backing_variable(ptr);
  	auto &expr_type = get_pointee_type(ptr_type.self);
  
  	const auto &iface_type = expression_type(stage_in_ptr_var_id);
  
  	if (!flattened_io)
  	{
  		// Simplest case for multi-patch workgroups, just unroll array as-is.
  		if (interface_index == uint32_t(-1))
  			return false;
  
  		expr += type_to_glsl(result_type) + "({ ";
  		uint32_t num_control_points = to_array_size_literal(result_type, uint32_t(result_type.array.size()) - 1);
  
  		for (uint32_t i = 0; i < num_control_points; i++)
  		{
  			const uint32_t indices[2] = { i, interface_index };
  			AccessChainMeta meta;
  			expr += access_chain_internal(stage_in_ptr_var_id, indices, 2,
  			                              ACCESS_CHAIN_INDEX_IS_LITERAL_BIT | ACCESS_CHAIN_PTR_CHAIN_BIT, &meta);
  			if (i + 1 < num_control_points)
  				expr += ", ";
  		}
  		expr += " })";
  	}
  	else if (result_type.array.size() > 2)
  	{
  		SPIRV_CROSS_THROW("Cannot load tessellation IO variables with more than 2 dimensions.");
  	}
  	else if (result_type.array.size() == 2)
  	{
  		if (!ptr_is_io_variable)
  			SPIRV_CROSS_THROW("Loading an array-of-array must be loaded directly from an IO variable.");
  		if (interface_index == uint32_t(-1))
  			SPIRV_CROSS_THROW("Interface index is unknown. Cannot continue.");
  		if (result_type.basetype == SPIRType::Struct || is_matrix(result_type))
  			SPIRV_CROSS_THROW("Cannot load array-of-array of composite type in tessellation IO.");
  
  		expr += type_to_glsl(result_type) + "({ ";
  		uint32_t num_control_points = to_array_size_literal(result_type, 1);
  		uint32_t base_interface_index = interface_index;
  
  		auto &sub_type = get<SPIRType>(result_type.parent_type);
  
  		for (uint32_t i = 0; i < num_control_points; i++)
  		{
  			expr += type_to_glsl(sub_type) + "({ ";
  			interface_index = base_interface_index;
  			uint32_t array_size = to_array_size_literal(result_type, 0);
  			for (uint32_t j = 0; j < array_size; j++, interface_index++)
  			{
  				const uint32_t indices[2] = { i, interface_index };
  
  				AccessChainMeta meta;
  				expr += access_chain_internal(stage_in_ptr_var_id, indices, 2,
  				                              ACCESS_CHAIN_INDEX_IS_LITERAL_BIT | ACCESS_CHAIN_PTR_CHAIN_BIT, &meta);
  				if (!is_matrix(sub_type) && sub_type.basetype != SPIRType::Struct &&
  					expr_type.vecsize > sub_type.vecsize)
  					expr += vector_swizzle(sub_type.vecsize, 0);
  
  				if (j + 1 < array_size)
  					expr += ", ";
  			}
  			expr += " })";
  			if (i + 1 < num_control_points)
  				expr += ", ";
  		}
  		expr += " })";
  	}
  	else if (result_type.basetype == SPIRType::Struct)
  	{
  		bool is_array_of_struct = is_array(result_type);
  		if (is_array_of_struct && !ptr_is_io_variable)
  			SPIRV_CROSS_THROW("Loading array of struct from IO variable must come directly from IO variable.");
  
  		uint32_t num_control_points = 1;
  		if (is_array_of_struct)
  		{
  			num_control_points = to_array_size_literal(result_type, 0);
  			expr += type_to_glsl(result_type) + "({ ";
  		}
  
  		auto &struct_type = is_array_of_struct ? get<SPIRType>(result_type.parent_type) : result_type;
  		assert(struct_type.array.empty());
  
  		for (uint32_t i = 0; i < num_control_points; i++)
  		{
  			expr += type_to_glsl(struct_type) + "{ ";
  			for (uint32_t j = 0; j < uint32_t(struct_type.member_types.size()); j++)
  			{
  				// The base interface index is stored per variable for structs.
  				if (var)
  				{
  					interface_index =
  					    get_extended_member_decoration(var->self, j, SPIRVCrossDecorationInterfaceMemberIndex);
  				}
  
  				if (interface_index == uint32_t(-1))
  					SPIRV_CROSS_THROW("Interface index is unknown. Cannot continue.");
  
  				const auto &mbr_type = get<SPIRType>(struct_type.member_types[j]);
  				const auto &expr_mbr_type = get<SPIRType>(expr_type.member_types[j]);
  				if (is_matrix(mbr_type) && ptr_type.storage == StorageClassInput)
  				{
  					expr += type_to_glsl(mbr_type) + "(";
  					for (uint32_t k = 0; k < mbr_type.columns; k++, interface_index++)
  					{
  						if (is_array_of_struct)
  						{
  							const uint32_t indices[2] = { i, interface_index };
  							AccessChainMeta meta;
  							expr += access_chain_internal(
  									stage_in_ptr_var_id, indices, 2,
  									ACCESS_CHAIN_INDEX_IS_LITERAL_BIT | ACCESS_CHAIN_PTR_CHAIN_BIT, &meta);
  						}
  						else
  							expr += to_expression(ptr) + "." + to_member_name(iface_type, interface_index);
  						if (expr_mbr_type.vecsize > mbr_type.vecsize)
  							expr += vector_swizzle(mbr_type.vecsize, 0);
  
  						if (k + 1 < mbr_type.columns)
  							expr += ", ";
  					}
  					expr += ")";
  				}
  				else if (is_array(mbr_type))
  				{
  					expr += type_to_glsl(mbr_type) + "({ ";
  					uint32_t array_size = to_array_size_literal(mbr_type, 0);
  					for (uint32_t k = 0; k < array_size; k++, interface_index++)
  					{
  						if (is_array_of_struct)
  						{
  							const uint32_t indices[2] = { i, interface_index };
  							AccessChainMeta meta;
  							expr += access_chain_internal(
  									stage_in_ptr_var_id, indices, 2,
  									ACCESS_CHAIN_INDEX_IS_LITERAL_BIT | ACCESS_CHAIN_PTR_CHAIN_BIT, &meta);
  						}
  						else
  							expr += to_expression(ptr) + "." + to_member_name(iface_type, interface_index);
  						if (expr_mbr_type.vecsize > mbr_type.vecsize)
  							expr += vector_swizzle(mbr_type.vecsize, 0);
  
  						if (k + 1 < array_size)
  							expr += ", ";
  					}
  					expr += " })";
  				}
  				else
  				{
  					if (is_array_of_struct)
  					{
  						const uint32_t indices[2] = { i, interface_index };
  						AccessChainMeta meta;
  						expr += access_chain_internal(stage_in_ptr_var_id, indices, 2,
  						                              ACCESS_CHAIN_INDEX_IS_LITERAL_BIT | ACCESS_CHAIN_PTR_CHAIN_BIT,
  						                              &meta);
  					}
  					else
  						expr += to_expression(ptr) + "." + to_member_name(iface_type, interface_index);
  					if (expr_mbr_type.vecsize > mbr_type.vecsize)
  						expr += vector_swizzle(mbr_type.vecsize, 0);
  				}
  
  				if (j + 1 < struct_type.member_types.size())
  					expr += ", ";
  			}
  			expr += " }";
  			if (i + 1 < num_control_points)
  				expr += ", ";
  		}
  		if (is_array_of_struct)
  			expr += " })";
  	}
  	else if (is_matrix(result_type))
  	{
  		bool is_array_of_matrix = is_array(result_type);
  		if (is_array_of_matrix && !ptr_is_io_variable)
  			SPIRV_CROSS_THROW("Loading array of matrix from IO variable must come directly from IO variable.");
  		if (interface_index == uint32_t(-1))
  			SPIRV_CROSS_THROW("Interface index is unknown. Cannot continue.");
  
  		if (is_array_of_matrix)
  		{
  			// Loading a matrix from each control point.
  			uint32_t base_interface_index = interface_index;
  			uint32_t num_control_points = to_array_size_literal(result_type, 0);
  			expr += type_to_glsl(result_type) + "({ ";
  
  			auto &matrix_type = get_variable_element_type(get<SPIRVariable>(ptr));
  
  			for (uint32_t i = 0; i < num_control_points; i++)
  			{
  				interface_index = base_interface_index;
  				expr += type_to_glsl(matrix_type) + "(";
  				for (uint32_t j = 0; j < result_type.columns; j++, interface_index++)
  				{
  					const uint32_t indices[2] = { i, interface_index };
  
  					AccessChainMeta meta;
  					expr += access_chain_internal(stage_in_ptr_var_id, indices, 2,
  					                              ACCESS_CHAIN_INDEX_IS_LITERAL_BIT | ACCESS_CHAIN_PTR_CHAIN_BIT, &meta);
  					if (expr_type.vecsize > result_type.vecsize)
  						expr += vector_swizzle(result_type.vecsize, 0);
  					if (j + 1 < result_type.columns)
  						expr += ", ";
  				}
  				expr += ")";
  				if (i + 1 < num_control_points)
  					expr += ", ";
  			}
  
  			expr += " })";
  		}
  		else
  		{
  			expr += type_to_glsl(result_type) + "(";
  			for (uint32_t i = 0; i < result_type.columns; i++, interface_index++)
  			{
  				expr += to_expression(ptr) + "." + to_member_name(iface_type, interface_index);
  				if (expr_type.vecsize > result_type.vecsize)
  					expr += vector_swizzle(result_type.vecsize, 0);
  				if (i + 1 < result_type.columns)
  					expr += ", ";
  			}
  			expr += ")";
  		}
  	}
  	else if (ptr_is_io_variable)
  	{
  		assert(is_array(result_type));
  		assert(result_type.array.size() == 1);
  		if (interface_index == uint32_t(-1))
  			SPIRV_CROSS_THROW("Interface index is unknown. Cannot continue.");
  
  		// We're loading an array directly from a global variable.
  		// This means we're loading one member from each control point.
  		expr += type_to_glsl(result_type) + "({ ";
  		uint32_t num_control_points = to_array_size_literal(result_type, 0);
  
  		for (uint32_t i = 0; i < num_control_points; i++)
  		{
  			const uint32_t indices[2] = { i, interface_index };
  
  			AccessChainMeta meta;
  			expr += access_chain_internal(stage_in_ptr_var_id, indices, 2,
  			                              ACCESS_CHAIN_INDEX_IS_LITERAL_BIT | ACCESS_CHAIN_PTR_CHAIN_BIT, &meta);
  			if (expr_type.vecsize > result_type.vecsize)
  				expr += vector_swizzle(result_type.vecsize, 0);
  
  			if (i + 1 < num_control_points)
  				expr += ", ";
  		}
  		expr += " })";
  	}
  	else
  	{
  		// We're loading an array from a concrete control point.
  		assert(is_array(result_type));
  		assert(result_type.array.size() == 1);
  		if (interface_index == uint32_t(-1))
  			SPIRV_CROSS_THROW("Interface index is unknown. Cannot continue.");
  
  		expr += type_to_glsl(result_type) + "({ ";
  		uint32_t array_size = to_array_size_literal(result_type, 0);
  		for (uint32_t i = 0; i < array_size; i++, interface_index++)
  		{
  			expr += to_expression(ptr) + "." + to_member_name(iface_type, interface_index);
  			if (expr_type.vecsize > result_type.vecsize)
  				expr += vector_swizzle(result_type.vecsize, 0);
  			if (i + 1 < array_size)
  				expr += ", ";
  		}
  		expr += " })";
  	}
  
  	emit_op(result_type_id, id, expr, false);
  	register_read(id, ptr, false);
  	return true;
  }
  
  bool CompilerMSL::emit_tessellation_access_chain(const uint32_t *ops, uint32_t length)
  {
  	// If this is a per-vertex output, remap it to the I/O array buffer.
  
  	// Any object which did not go through IO flattening shenanigans will go there instead.
  	// We will unflatten on-demand instead as needed, but not all possible cases can be supported, especially with arrays.
  
  	auto *var = maybe_get_backing_variable(ops[2]);
  	bool patch = false;
  	bool flat_data = false;
  	bool ptr_is_chain = false;
  	bool flatten_composites = false;
  
  	bool is_block = false;
  
  	if (var)
  		is_block = has_decoration(get_variable_data_type(*var).self, DecorationBlock);
  
  	if (var)
  	{
  		flatten_composites = variable_storage_requires_stage_io(var->storage);
  		patch = has_decoration(ops[2], DecorationPatch) || is_patch_block(get_variable_data_type(*var));
  
  		// Should match strip_array in add_interface_block.
  		flat_data = var->storage == StorageClassInput ||
  		            (var->storage == StorageClassOutput && get_execution_model() == ExecutionModelTessellationControl);
  
  		// Patch inputs are treated as normal block IO variables, so they don't deal with this path at all.
  		if (patch && (!is_block || var->storage == StorageClassInput))
  			flat_data = false;
  
  		// We might have a chained access chain, where
  		// we first take the access chain to the control point, and then we chain into a member or something similar.
  		// In this case, we need to skip gl_in/gl_out remapping.
  		// Also, skip ptr chain for patches.
  		ptr_is_chain = var->self != ID(ops[2]);
  	}
  
  	bool builtin_variable = false;
  	bool variable_is_flat = false;
  
  	if (var && flat_data)
  	{
  		builtin_variable = is_builtin_variable(*var);
  
  		BuiltIn bi_type = BuiltInMax;
  		if (builtin_variable && !is_block)
  			bi_type = BuiltIn(get_decoration(var->self, DecorationBuiltIn));
  
  		variable_is_flat = !builtin_variable || is_block ||
  		                   bi_type == BuiltInPosition || bi_type == BuiltInPointSize ||
  		                   bi_type == BuiltInClipDistance || bi_type == BuiltInCullDistance;
  	}
  
  	if (variable_is_flat)
  	{
  		// If output is masked, it is emitted as a "normal" variable, just go through normal code paths.
  		// Only check this for the first level of access chain.
  		// Dealing with this for partial access chains should be possible, but awkward.
  		if (var->storage == StorageClassOutput && !ptr_is_chain)
  		{
  			bool masked = false;
  			if (is_block)
  			{
  				uint32_t relevant_member_index = patch ? 3 : 4;
  				// FIXME: This won't work properly if the application first access chains into gl_out element,
  				// then access chains into the member. Super weird, but theoretically possible ...
  				if (length > relevant_member_index)
  				{
  					uint32_t mbr_idx = get<SPIRConstant>(ops[relevant_member_index]).scalar();
  					masked = is_stage_output_block_member_masked(*var, mbr_idx, true);
  				}
  			}
  			else if (var)
  				masked = is_stage_output_variable_masked(*var);
  
  			if (masked)
  				return false;
  		}
  
  		AccessChainMeta meta;
  		SmallVector<uint32_t> indices;
  		uint32_t next_id = ir.increase_bound_by(1);
  
  		indices.reserve(length - 3 + 1);
  
  		uint32_t first_non_array_index = (ptr_is_chain ? 3 : 4) - (patch ? 1 : 0);
  
  		VariableID stage_var_id;
  		if (patch)
  			stage_var_id = var->storage == StorageClassInput ? patch_stage_in_var_id : patch_stage_out_var_id;
  		else
  			stage_var_id = var->storage == StorageClassInput ? stage_in_ptr_var_id : stage_out_ptr_var_id;
  
  		VariableID ptr = ptr_is_chain ? VariableID(ops[2]) : stage_var_id;
  		if (!ptr_is_chain && !patch)
  		{
  			// Index into gl_in/gl_out with first array index.
  			indices.push_back(ops[first_non_array_index - 1]);
  		}
  
  		auto &result_ptr_type = get<SPIRType>(ops[0]);
  
  		uint32_t const_mbr_id = next_id++;
  		uint32_t index = get_extended_decoration(ops[2], SPIRVCrossDecorationInterfaceMemberIndex);
  
  		// If we have a pointer chain expression, and we are no longer pointing to a composite
  		// object, we are in the clear. There is no longer a need to flatten anything.
  		bool further_access_chain_is_trivial = false;
  		if (ptr_is_chain && flatten_composites)
  		{
  			auto &ptr_type = expression_type(ptr);
  			if (!is_array(ptr_type) && !is_matrix(ptr_type) && ptr_type.basetype != SPIRType::Struct)
  				further_access_chain_is_trivial = true;
  		}
  
  		if (!further_access_chain_is_trivial && (flatten_composites || is_block))
  		{
  			uint32_t i = first_non_array_index;
  			auto *type = &get_variable_element_type(*var);
  			if (index == uint32_t(-1) && length >= (first_non_array_index + 1))
  			{
  				// Maybe this is a struct type in the input class, in which case
  				// we put it as a decoration on the corresponding member.
  				uint32_t mbr_idx = get_constant(ops[first_non_array_index]).scalar();
  				index = get_extended_member_decoration(var->self, mbr_idx,
  				                                       SPIRVCrossDecorationInterfaceMemberIndex);
  				assert(index != uint32_t(-1));
  				i++;
  				type = &get<SPIRType>(type->member_types[mbr_idx]);
  			}
  
  			// In this case, we're poking into flattened structures and arrays, so now we have to
  			// combine the following indices. If we encounter a non-constant index,
  			// we're hosed.
  			for (; flatten_composites && i < length; ++i)
  			{
  				if (!is_array(*type) && !is_matrix(*type) && type->basetype != SPIRType::Struct)
  					break;
  
  				auto *c = maybe_get<SPIRConstant>(ops[i]);
  				if (!c || c->specialization)
  					SPIRV_CROSS_THROW("Trying to dynamically index into an array interface variable in tessellation. "
  					                  "This is currently unsupported.");
  
  				// We're in flattened space, so just increment the member index into IO block.
  				// We can only do this once in the current implementation, so either:
  				// Struct, Matrix or 1-dimensional array for a control point.
  				if (type->basetype == SPIRType::Struct && var->storage == StorageClassOutput)
  				{
  					// Need to consider holes, since individual block members might be masked away.
  					uint32_t mbr_idx = c->scalar();
  					for (uint32_t j = 0; j < mbr_idx; j++)
  						if (!is_stage_output_block_member_masked(*var, j, true))
  							index++;
  				}
  				else
  					index += c->scalar();
  
  				if (type->parent_type)
  					type = &get<SPIRType>(type->parent_type);
  				else if (type->basetype == SPIRType::Struct)
  					type = &get<SPIRType>(type->member_types[c->scalar()]);
  			}
  
  			// We're not going to emit the actual member name, we let any further OpLoad take care of that.
  			// Tag the access chain with the member index we're referencing.
  			bool defer_access_chain = flatten_composites && (is_matrix(result_ptr_type) || is_array(result_ptr_type) ||
  			                                                 result_ptr_type.basetype == SPIRType::Struct);
  
  			if (!defer_access_chain)
  			{
  				// Access the appropriate member of gl_in/gl_out.
  				set<SPIRConstant>(const_mbr_id, get_uint_type_id(), index, false);
  				indices.push_back(const_mbr_id);
  
  				// Member index is now irrelevant.
  				index = uint32_t(-1);
  
  				// Append any straggling access chain indices.
  				if (i < length)
  					indices.insert(indices.end(), ops + i, ops + length);
  			}
  			else
  			{
  				// We must have consumed the entire access chain if we're deferring it.
  				assert(i == length);
  			}
  
  			if (index != uint32_t(-1))
  				set_extended_decoration(ops[1], SPIRVCrossDecorationInterfaceMemberIndex, index);
  			else
  				unset_extended_decoration(ops[1], SPIRVCrossDecorationInterfaceMemberIndex);
  		}
  		else
  		{
  			if (index != uint32_t(-1))
  			{
  				set<SPIRConstant>(const_mbr_id, get_uint_type_id(), index, false);
  				indices.push_back(const_mbr_id);
  			}
  
  			// Member index is now irrelevant.
  			index = uint32_t(-1);
  			unset_extended_decoration(ops[1], SPIRVCrossDecorationInterfaceMemberIndex);
  
  			indices.insert(indices.end(), ops + first_non_array_index, ops + length);
  		}
  
  		// We use the pointer to the base of the input/output array here,
  		// so this is always a pointer chain.
  		string e;
  
  		if (!ptr_is_chain)
  		{
  			// This is the start of an access chain, use ptr_chain to index into control point array.
  			e = access_chain(ptr, indices.data(), uint32_t(indices.size()), result_ptr_type, &meta, !patch);
  		}
  		else
  		{
  			// If we're accessing a struct, we need to use member indices which are based on the IO block,
  			// not actual struct type, so we have to use a split access chain here where
  			// first path resolves the control point index, i.e. gl_in[index], and second half deals with
  			// looking up flattened member name.
  
  			// However, it is possible that we partially accessed a struct,
  			// by taking pointer to member inside the control-point array.
  			// For this case, we fall back to a natural access chain since we have already dealt with remapping struct members.
  			// One way to check this here is if we have 2 implied read expressions.
  			// First one is the gl_in/gl_out struct itself, then an index into that array.
  			// If we have traversed further, we use a normal access chain formulation.
  			auto *ptr_expr = maybe_get<SPIRExpression>(ptr);
  			bool split_access_chain_formulation = flatten_composites && ptr_expr &&
  			                                      ptr_expr->implied_read_expressions.size() == 2 &&
  			                                      !further_access_chain_is_trivial;
  
  			if (split_access_chain_formulation)
  			{
  				e = join(to_expression(ptr),
  				         access_chain_internal(stage_var_id, indices.data(), uint32_t(indices.size()),
  				                               ACCESS_CHAIN_CHAIN_ONLY_BIT, &meta));
  			}
  			else
  			{
  				e = access_chain_internal(ptr, indices.data(), uint32_t(indices.size()), 0, &meta);
  			}
  		}
  
  		// Get the actual type of the object that was accessed. If it's a vector type and we changed it,
  		// then we'll need to add a swizzle.
  		// For this, we can't necessarily rely on the type of the base expression, because it might be
  		// another access chain, and it will therefore already have the "correct" type.
  		auto *expr_type = &get_variable_data_type(*var);
  		if (has_extended_decoration(ops[2], SPIRVCrossDecorationTessIOOriginalInputTypeID))
  			expr_type = &get<SPIRType>(get_extended_decoration(ops[2], SPIRVCrossDecorationTessIOOriginalInputTypeID));
  		for (uint32_t i = 3; i < length; i++)
  		{
  			if (!is_array(*expr_type) && expr_type->basetype == SPIRType::Struct)
  				expr_type = &get<SPIRType>(expr_type->member_types[get<SPIRConstant>(ops[i]).scalar()]);
  			else
  				expr_type = &get<SPIRType>(expr_type->parent_type);
  		}
  		if (!is_array(*expr_type) && !is_matrix(*expr_type) && expr_type->basetype != SPIRType::Struct &&
  		    expr_type->vecsize > result_ptr_type.vecsize)
  			e += vector_swizzle(result_ptr_type.vecsize, 0);
  
  		auto &expr = set<SPIRExpression>(ops[1], move(e), ops[0], should_forward(ops[2]));
  		expr.loaded_from = var->self;
  		expr.need_transpose = meta.need_transpose;
  		expr.access_chain = true;
  
  		// Mark the result as being packed if necessary.
  		if (meta.storage_is_packed)
  			set_extended_decoration(ops[1], SPIRVCrossDecorationPhysicalTypePacked);
  		if (meta.storage_physical_type != 0)
  			set_extended_decoration(ops[1], SPIRVCrossDecorationPhysicalTypeID, meta.storage_physical_type);
  		if (meta.storage_is_invariant)
  			set_decoration(ops[1], DecorationInvariant);
  		// Save the type we found in case the result is used in another access chain.
  		set_extended_decoration(ops[1], SPIRVCrossDecorationTessIOOriginalInputTypeID, expr_type->self);
  
  		// If we have some expression dependencies in our access chain, this access chain is technically a forwarded
  		// temporary which could be subject to invalidation.
  		// Need to assume we're forwarded while calling inherit_expression_depdendencies.
  		forwarded_temporaries.insert(ops[1]);
  		// The access chain itself is never forced to a temporary, but its dependencies might.
  		suppressed_usage_tracking.insert(ops[1]);
  
  		for (uint32_t i = 2; i < length; i++)
  		{
  			inherit_expression_dependencies(ops[1], ops[i]);
  			add_implied_read_expression(expr, ops[i]);
  		}
  
  		// If we have no dependencies after all, i.e., all indices in the access chain are immutable temporaries,
  		// we're not forwarded after all.
  		if (expr.expression_dependencies.empty())
  			forwarded_temporaries.erase(ops[1]);
  
  		return true;
  	}
  
  	// If this is the inner tessellation level, and we're tessellating triangles,
  	// drop the last index. It isn't an array in this case, so we can't have an
  	// array reference here. We need to make this ID a variable instead of an
  	// expression so we don't try to dereference it as a variable pointer.
  	// Don't do this if the index is a constant 1, though. We need to drop stores
  	// to that one.
  	auto *m = ir.find_meta(var ? var->self : ID(0));
  	if (get_execution_model() == ExecutionModelTessellationControl && var && m &&
  	    m->decoration.builtin_type == BuiltInTessLevelInner && get_entry_point().flags.get(ExecutionModeTriangles))
  	{
  		auto *c = maybe_get<SPIRConstant>(ops[3]);
  		if (c && c->scalar() == 1)
  			return false;
  		auto &dest_var = set<SPIRVariable>(ops[1], *var);
  		dest_var.basetype = ops[0];
  		ir.meta[ops[1]] = ir.meta[ops[2]];
  		inherit_expression_dependencies(ops[1], ops[2]);
  		return true;
  	}
  
  	return false;
  }
  
  bool CompilerMSL::is_out_of_bounds_tessellation_level(uint32_t id_lhs)
  {
  	if (!get_entry_point().flags.get(ExecutionModeTriangles))
  		return false;
  
  	// In SPIR-V, TessLevelInner always has two elements and TessLevelOuter always has
  	// four. This is true even if we are tessellating triangles. This allows clients
  	// to use a single tessellation control shader with multiple tessellation evaluation
  	// shaders.
  	// In Metal, however, only the first element of TessLevelInner and the first three
  	// of TessLevelOuter are accessible. This stems from how in Metal, the tessellation
  	// levels must be stored to a dedicated buffer in a particular format that depends
  	// on the patch type. Therefore, in Triangles mode, any access to the second
  	// inner level or the fourth outer level must be dropped.
  	const auto *e = maybe_get<SPIRExpression>(id_lhs);
  	if (!e || !e->access_chain)
  		return false;
  	BuiltIn builtin = BuiltIn(get_decoration(e->loaded_from, DecorationBuiltIn));
  	if (builtin != BuiltInTessLevelInner && builtin != BuiltInTessLevelOuter)
  		return false;
  	auto *c = maybe_get<SPIRConstant>(e->implied_read_expressions[1]);
  	if (!c)
  		return false;
  	return (builtin == BuiltInTessLevelInner && c->scalar() == 1) ||
  	       (builtin == BuiltInTessLevelOuter && c->scalar() == 3);
  }
  
  void CompilerMSL::prepare_access_chain_for_scalar_access(std::string &expr, const SPIRType &type,
                                                           spv::StorageClass storage, bool &is_packed)
  {
  	// If there is any risk of writes happening with the access chain in question,
  	// and there is a risk of concurrent write access to other components,
  	// we must cast the access chain to a plain pointer to ensure we only access the exact scalars we expect.
  	// The MSL compiler refuses to allow component-level access for any non-packed vector types.
  	if (!is_packed && (storage == StorageClassStorageBuffer || storage == StorageClassWorkgroup))
  	{
  		const char *addr_space = storage == StorageClassWorkgroup ? "threadgroup" : "device";
  		expr = join("((", addr_space, " ", type_to_glsl(type), "*)&", enclose_expression(expr), ")");
  
  		// Further indexing should happen with packed rules (array index, not swizzle).
  		is_packed = true;
  	}
  }
  
  bool CompilerMSL::access_chain_needs_stage_io_builtin_translation(uint32_t base)
  {
  	auto *var = maybe_get_backing_variable(base);
  	if (!var || !is_tessellation_shader())
  		return true;
  
  	// We only need to rewrite builtin access chains when accessing flattened builtins like gl_ClipDistance_N.
  	// Avoid overriding it back to just gl_ClipDistance.
  	// This can only happen in scenarios where we cannot flatten/unflatten access chains, so, the only case
  	// where this triggers is evaluation shader inputs.
  	bool redirect_builtin = get_execution_model() == ExecutionModelTessellationEvaluation ?
  	                        var->storage == StorageClassOutput : false;
  	return redirect_builtin;
  }
  
  // Sets the interface member index for an access chain to a pull-model interpolant.
  void CompilerMSL::fix_up_interpolant_access_chain(const uint32_t *ops, uint32_t length)
  {
  	auto *var = maybe_get_backing_variable(ops[2]);
  	if (!var || !pull_model_inputs.count(var->self))
  		return;
  	// Get the base index.
  	uint32_t interface_index;
  	auto &var_type = get_variable_data_type(*var);
  	auto &result_type = get<SPIRType>(ops[0]);
  	auto *type = &var_type;
  	if (has_extended_decoration(ops[2], SPIRVCrossDecorationInterfaceMemberIndex))
  	{
  		interface_index = get_extended_decoration(ops[2], SPIRVCrossDecorationInterfaceMemberIndex);
  	}
  	else
  	{
  		// Assume an access chain into a struct variable.
  		assert(var_type.basetype == SPIRType::Struct);
  		auto &c = get<SPIRConstant>(ops[3 + var_type.array.size()]);
  		interface_index =
  		    get_extended_member_decoration(var->self, c.scalar(), SPIRVCrossDecorationInterfaceMemberIndex);
  	}
  	// Accumulate indices. We'll have to skip over the one for the struct, if present, because we already accounted
  	// for that getting the base index.
  	for (uint32_t i = 3; i < length; ++i)
  	{
  		if (is_vector(*type) && !is_array(*type) && is_scalar(result_type))
  		{
  			// We don't want to combine the next index. Actually, we need to save it
  			// so we know to apply a swizzle to the result of the interpolation.
  			set_extended_decoration(ops[1], SPIRVCrossDecorationInterpolantComponentExpr, ops[i]);
  			break;
  		}
  
  		auto *c = maybe_get<SPIRConstant>(ops[i]);
  		if (!c || c->specialization)
  			SPIRV_CROSS_THROW("Trying to dynamically index into an array interface variable using pull-model "
  			                  "interpolation. This is currently unsupported.");
  
  		if (type->parent_type)
  			type = &get<SPIRType>(type->parent_type);
  		else if (type->basetype == SPIRType::Struct)
  			type = &get<SPIRType>(type->member_types[c->scalar()]);
  
  		if (!has_extended_decoration(ops[2], SPIRVCrossDecorationInterfaceMemberIndex) &&
  		    i - 3 == var_type.array.size())
  			continue;
  
  		interface_index += c->scalar();
  	}
  	// Save this to the access chain itself so we can recover it later when calling an interpolation function.
  	set_extended_decoration(ops[1], SPIRVCrossDecorationInterfaceMemberIndex, interface_index);
  }
  
  // Override for MSL-specific syntax instructions
  void CompilerMSL::emit_instruction(const Instruction &instruction)
  {
  #define MSL_BOP(op) emit_binary_op(ops[0], ops[1], ops[2], ops[3], #op)
  #define MSL_BOP_CAST(op, type) \
  	emit_binary_op_cast(ops[0], ops[1], ops[2], ops[3], #op, type, opcode_is_sign_invariant(opcode))
  #define MSL_UOP(op) emit_unary_op(ops[0], ops[1], ops[2], #op)
  #define MSL_QFOP(op) emit_quaternary_func_op(ops[0], ops[1], ops[2], ops[3], ops[4], ops[5], #op)
  #define MSL_TFOP(op) emit_trinary_func_op(ops[0], ops[1], ops[2], ops[3], ops[4], #op)
  #define MSL_BFOP(op) emit_binary_func_op(ops[0], ops[1], ops[2], ops[3], #op)
  #define MSL_BFOP_CAST(op, type) \
  	emit_binary_func_op_cast(ops[0], ops[1], ops[2], ops[3], #op, type, opcode_is_sign_invariant(opcode))
  #define MSL_UFOP(op) emit_unary_func_op(ops[0], ops[1], ops[2], #op)
  #define MSL_UNORD_BOP(op) emit_binary_unord_op(ops[0], ops[1], ops[2], ops[3], #op)
  
  	auto ops = stream(instruction);
  	auto opcode = static_cast<Op>(instruction.op);
  
  	// If we need to do implicit bitcasts, make sure we do it with the correct type.
  	uint32_t integer_width = get_integer_width_for_instruction(instruction);
  	auto int_type = to_signed_basetype(integer_width);
  	auto uint_type = to_unsigned_basetype(integer_width);
  
  	switch (opcode)
  	{
  	case OpLoad:
  	{
  		uint32_t id = ops[1];
  		uint32_t ptr = ops[2];
  		if (is_tessellation_shader())
  		{
  			if (!emit_tessellation_io_load(ops[0], id, ptr))
  				CompilerGLSL::emit_instruction(instruction);
  		}
  		else
  		{
  			// Sample mask input for Metal is not an array
  			if (BuiltIn(get_decoration(ptr, DecorationBuiltIn)) == BuiltInSampleMask)
  				set_decoration(id, DecorationBuiltIn, BuiltInSampleMask);
  			CompilerGLSL::emit_instruction(instruction);
  		}
  		break;
  	}
  
  	// Comparisons
  	case OpIEqual:
  		MSL_BOP_CAST(==, int_type);
  		break;
  
  	case OpLogicalEqual:
  	case OpFOrdEqual:
  		MSL_BOP(==);
  		break;
  
  	case OpINotEqual:
  		MSL_BOP_CAST(!=, int_type);
  		break;
  
  	case OpLogicalNotEqual:
  	case OpFOrdNotEqual:
  		MSL_BOP(!=);
  		break;
  
  	case OpUGreaterThan:
  		MSL_BOP_CAST(>, uint_type);
  		break;
  
  	case OpSGreaterThan:
  		MSL_BOP_CAST(>, int_type);
  		break;
  
  	case OpFOrdGreaterThan:
  		MSL_BOP(>);
  		break;
  
  	case OpUGreaterThanEqual:
  		MSL_BOP_CAST(>=, uint_type);
  		break;
  
  	case OpSGreaterThanEqual:
  		MSL_BOP_CAST(>=, int_type);
  		break;
  
  	case OpFOrdGreaterThanEqual:
  		MSL_BOP(>=);
  		break;
  
  	case OpULessThan:
  		MSL_BOP_CAST(<, uint_type);
  		break;
  
  	case OpSLessThan:
  		MSL_BOP_CAST(<, int_type);
  		break;
  
  	case OpFOrdLessThan:
  		MSL_BOP(<);
  		break;
  
  	case OpULessThanEqual:
  		MSL_BOP_CAST(<=, uint_type);
  		break;
  
  	case OpSLessThanEqual:
  		MSL_BOP_CAST(<=, int_type);
  		break;
  
  	case OpFOrdLessThanEqual:
  		MSL_BOP(<=);
  		break;
  
  	case OpFUnordEqual:
  		MSL_UNORD_BOP(==);
  		break;
  
  	case OpFUnordNotEqual:
  		MSL_UNORD_BOP(!=);
  		break;
  
  	case OpFUnordGreaterThan:
  		MSL_UNORD_BOP(>);
  		break;
  
  	case OpFUnordGreaterThanEqual:
  		MSL_UNORD_BOP(>=);
  		break;
  
  	case OpFUnordLessThan:
  		MSL_UNORD_BOP(<);
  		break;
  
  	case OpFUnordLessThanEqual:
  		MSL_UNORD_BOP(<=);
  		break;
  
  	// Derivatives
  	case OpDPdx:
  	case OpDPdxFine:
  	case OpDPdxCoarse:
  		MSL_UFOP(dfdx);
  		register_control_dependent_expression(ops[1]);
  		break;
  
  	case OpDPdy:
  	case OpDPdyFine:
  	case OpDPdyCoarse:
  		MSL_UFOP(dfdy);
  		register_control_dependent_expression(ops[1]);
  		break;
  
  	case OpFwidth:
  	case OpFwidthCoarse:
  	case OpFwidthFine:
  		MSL_UFOP(fwidth);
  		register_control_dependent_expression(ops[1]);
  		break;
  
  	// Bitfield
  	case OpBitFieldInsert:
  	{
  		emit_bitfield_insert_op(ops[0], ops[1], ops[2], ops[3], ops[4], ops[5], "insert_bits", SPIRType::UInt);
  		break;
  	}
  
  	case OpBitFieldSExtract:
  	{
  		emit_trinary_func_op_bitextract(ops[0], ops[1], ops[2], ops[3], ops[4], "extract_bits", int_type, int_type,
  		                                SPIRType::UInt, SPIRType::UInt);
  		break;
  	}
  
  	case OpBitFieldUExtract:
  	{
  		emit_trinary_func_op_bitextract(ops[0], ops[1], ops[2], ops[3], ops[4], "extract_bits", uint_type, uint_type,
  		                                SPIRType::UInt, SPIRType::UInt);
  		break;
  	}
  
  	case OpBitReverse:
  		// BitReverse does not have issues with sign since result type must match input type.
  		MSL_UFOP(reverse_bits);
  		break;
  
  	case OpBitCount:
  	{
  		auto basetype = expression_type(ops[2]).basetype;
  		emit_unary_func_op_cast(ops[0], ops[1], ops[2], "popcount", basetype, basetype);
  		break;
  	}
  
  	case OpFRem:
  		MSL_BFOP(fmod);
  		break;
  
  	case OpFMul:
  		if (msl_options.invariant_float_math || has_decoration(ops[1], DecorationNoContraction))
  			MSL_BFOP(spvFMul);
  		else
  			MSL_BOP(*);
  		break;
  
  	case OpFAdd:
  		if (msl_options.invariant_float_math || has_decoration(ops[1], DecorationNoContraction))
  			MSL_BFOP(spvFAdd);
  		else
  			MSL_BOP(+);
  		break;
  
  	case OpFSub:
  		if (msl_options.invariant_float_math || has_decoration(ops[1], DecorationNoContraction))
  			MSL_BFOP(spvFSub);
  		else
  			MSL_BOP(-);
  		break;
  
  	// Atomics
  	case OpAtomicExchange:
  	{
  		uint32_t result_type = ops[0];
  		uint32_t id = ops[1];
  		uint32_t ptr = ops[2];
  		uint32_t mem_sem = ops[4];
  		uint32_t val = ops[5];
  		emit_atomic_func_op(result_type, id, "atomic_exchange_explicit", mem_sem, mem_sem, false, ptr, val);
  		break;
  	}
  
  	case OpAtomicCompareExchange:
  	{
  		uint32_t result_type = ops[0];
  		uint32_t id = ops[1];
  		uint32_t ptr = ops[2];
  		uint32_t mem_sem_pass = ops[4];
  		uint32_t mem_sem_fail = ops[5];
  		uint32_t val = ops[6];
  		uint32_t comp = ops[7];
  		emit_atomic_func_op(result_type, id, "atomic_compare_exchange_weak_explicit", mem_sem_pass, mem_sem_fail, true,
  		                    ptr, comp, true, false, val);
  		break;
  	}
  
  	case OpAtomicCompareExchangeWeak:
  		SPIRV_CROSS_THROW("OpAtomicCompareExchangeWeak is only supported in kernel profile.");
  
  	case OpAtomicLoad:
  	{
  		uint32_t result_type = ops[0];
  		uint32_t id = ops[1];
  		uint32_t ptr = ops[2];
  		uint32_t mem_sem = ops[4];
  		emit_atomic_func_op(result_type, id, "atomic_load_explicit", mem_sem, mem_sem, false, ptr, 0);
  		break;
  	}
  
  	case OpAtomicStore:
  	{
  		uint32_t result_type = expression_type(ops[0]).self;
  		uint32_t id = ops[0];
  		uint32_t ptr = ops[0];
  		uint32_t mem_sem = ops[2];
  		uint32_t val = ops[3];
  		emit_atomic_func_op(result_type, id, "atomic_store_explicit", mem_sem, mem_sem, false, ptr, val);
  		break;
  	}
  
  #define MSL_AFMO_IMPL(op, valsrc, valconst)                                                                      \
  	do                                                                                                           \
  	{                                                                                                            \
  		uint32_t result_type = ops[0];                                                                           \
  		uint32_t id = ops[1];                                                                                    \
  		uint32_t ptr = ops[2];                                                                                   \
  		uint32_t mem_sem = ops[4];                                                                               \
  		uint32_t val = valsrc;                                                                                   \
  		emit_atomic_func_op(result_type, id, "atomic_fetch_" #op "_explicit", mem_sem, mem_sem, false, ptr, val, \
  		                    false, valconst);                                                                    \
  	} while (false)
  
  #define MSL_AFMO(op) MSL_AFMO_IMPL(op, ops[5], false)
  #define MSL_AFMIO(op) MSL_AFMO_IMPL(op, 1, true)
  
  	case OpAtomicIIncrement:
  		MSL_AFMIO(add);
  		break;
  
  	case OpAtomicIDecrement:
  		MSL_AFMIO(sub);
  		break;
  
  	case OpAtomicIAdd:
  		MSL_AFMO(add);
  		break;
  
  	case OpAtomicISub:
  		MSL_AFMO(sub);
  		break;
  
  	case OpAtomicSMin:
  	case OpAtomicUMin:
  		MSL_AFMO(min);
  		break;
  
  	case OpAtomicSMax:
  	case OpAtomicUMax:
  		MSL_AFMO(max);
  		break;
  
  	case OpAtomicAnd:
  		MSL_AFMO(and);
  		break;
  
  	case OpAtomicOr:
  		MSL_AFMO(or);
  		break;
  
  	case OpAtomicXor:
  		MSL_AFMO(xor);
  		break;
  
  	// Images
  
  	// Reads == Fetches in Metal
  	case OpImageRead:
  	{
  		// Mark that this shader reads from this image
  		uint32_t img_id = ops[2];
  		auto &type = expression_type(img_id);
  		if (type.image.dim != DimSubpassData)
  		{
  			auto *p_var = maybe_get_backing_variable(img_id);
  			if (p_var && has_decoration(p_var->self, DecorationNonReadable))
  			{
  				unset_decoration(p_var->self, DecorationNonReadable);
  				force_recompile();
  			}
  		}
  
  		emit_texture_op(instruction, false);
  		break;
  	}
  
  	// Emulate texture2D atomic operations
  	case OpImageTexelPointer:
  	{
  		// When using the pointer, we need to know which variable it is actually loaded from.
  		auto *var = maybe_get_backing_variable(ops[2]);
  		if (var && atomic_image_vars.count(var->self))
  		{
  			uint32_t result_type = ops[0];
  			uint32_t id = ops[1];
  
  			std::string coord = to_expression(ops[3]);
  			auto &type = expression_type(ops[2]);
  			if (type.image.dim == Dim2D)
  			{
  				coord = join("spvImage2DAtomicCoord(", coord, ", ", to_expression(ops[2]), ")");
  			}
  
  			auto &e = set<SPIRExpression>(id, join(to_expression(ops[2]), "_atomic[", coord, "]"), result_type, true);
  			e.loaded_from = var ? var->self : ID(0);
  			inherit_expression_dependencies(id, ops[3]);
  		}
  		else
  		{
  			uint32_t result_type = ops[0];
  			uint32_t id = ops[1];
  			auto &e =
  			    set<SPIRExpression>(id, join(to_expression(ops[2]), ", ", to_expression(ops[3])), result_type, true);
  
  			// When using the pointer, we need to know which variable it is actually loaded from.
  			e.loaded_from = var ? var->self : ID(0);
  			inherit_expression_dependencies(id, ops[3]);
  		}
  		break;
  	}
  
  	case OpImageWrite:
  	{
  		uint32_t img_id = ops[0];
  		uint32_t coord_id = ops[1];
  		uint32_t texel_id = ops[2];
  		const uint32_t *opt = &ops[3];
  		uint32_t length = instruction.length - 3;
  
  		// Bypass pointers because we need the real image struct
  		auto &type = expression_type(img_id);
  		auto &img_type = get<SPIRType>(type.self);
  
  		// Ensure this image has been marked as being written to and force a
  		// recommpile so that the image type output will include write access
  		auto *p_var = maybe_get_backing_variable(img_id);
  		if (p_var && has_decoration(p_var->self, DecorationNonWritable))
  		{
  			unset_decoration(p_var->self, DecorationNonWritable);
  			force_recompile();
  		}
  
  		bool forward = false;
  		uint32_t bias = 0;
  		uint32_t lod = 0;
  		uint32_t flags = 0;
  
  		if (length)
  		{
  			flags = *opt++;
  			length--;
  		}
  
  		auto test = [&](uint32_t &v, uint32_t flag) {
  			if (length && (flags & flag))
  			{
  				v = *opt++;
  				length--;
  			}
  		};
  
  		test(bias, ImageOperandsBiasMask);
  		test(lod, ImageOperandsLodMask);
  
  		auto &texel_type = expression_type(texel_id);
  		auto store_type = texel_type;
  		store_type.vecsize = 4;
  
  		TextureFunctionArguments args = {};
  		args.base.img = img_id;
  		args.base.imgtype = &img_type;
  		args.base.is_fetch = true;
  		args.coord = coord_id;
  		args.lod = lod;
  		statement(join(to_expression(img_id), ".write(",
  		               remap_swizzle(store_type, texel_type.vecsize, to_expression(texel_id)), ", ",
  		               CompilerMSL::to_function_args(args, &forward), ");"));
  
  		if (p_var && variable_storage_is_aliased(*p_var))
  			flush_all_aliased_variables();
  
  		break;
  	}
  
  	case OpImageQuerySize:
  	case OpImageQuerySizeLod:
  	{
  		uint32_t rslt_type_id = ops[0];
  		auto &rslt_type = get<SPIRType>(rslt_type_id);
  
  		uint32_t id = ops[1];
  
  		uint32_t img_id = ops[2];
  		string img_exp = to_expression(img_id);
  		auto &img_type = expression_type(img_id);
  		Dim img_dim = img_type.image.dim;
  		bool img_is_array = img_type.image.arrayed;
  
  		if (img_type.basetype != SPIRType::Image)
  			SPIRV_CROSS_THROW("Invalid type for OpImageQuerySize.");
  
  		string lod;
  		if (opcode == OpImageQuerySizeLod)
  		{
  			// LOD index defaults to zero, so don't bother outputing level zero index
  			string decl_lod = to_expression(ops[3]);
  			if (decl_lod != "0")
  				lod = decl_lod;
  		}
  
  		string expr = type_to_glsl(rslt_type) + "(";
  		expr += img_exp + ".get_width(" + lod + ")";
  
  		if (img_dim == Dim2D || img_dim == DimCube || img_dim == Dim3D)
  			expr += ", " + img_exp + ".get_height(" + lod + ")";
  
  		if (img_dim == Dim3D)
  			expr += ", " + img_exp + ".get_depth(" + lod + ")";
  
  		if (img_is_array)
  		{
  			expr += ", " + img_exp + ".get_array_size()";
  			if (img_dim == DimCube && msl_options.emulate_cube_array)
  				expr += " / 6";
  		}
  
  		expr += ")";
  
  		emit_op(rslt_type_id, id, expr, should_forward(img_id));
  
  		break;
  	}
  
  	case OpImageQueryLod:
  	{
  		if (!msl_options.supports_msl_version(2, 2))
  			SPIRV_CROSS_THROW("ImageQueryLod is only supported on MSL 2.2 and up.");
  		uint32_t result_type = ops[0];
  		uint32_t id = ops[1];
  		uint32_t image_id = ops[2];
  		uint32_t coord_id = ops[3];
  		emit_uninitialized_temporary_expression(result_type, id);
  
  		auto sampler_expr = to_sampler_expression(image_id);
  		auto *combined = maybe_get<SPIRCombinedImageSampler>(image_id);
  		auto image_expr = combined ? to_expression(combined->image) : to_expression(image_id);
  
  		// TODO: It is unclear if calculcate_clamped_lod also conditionally rounds
  		// the reported LOD based on the sampler. NEAREST miplevel should
  		// round the LOD, but LINEAR miplevel should not round.
  		// Let's hope this does not become an issue ...
  		statement(to_expression(id), ".x = ", image_expr, ".calculate_clamped_lod(", sampler_expr, ", ",
  		          to_expression(coord_id), ");");
  		statement(to_expression(id), ".y = ", image_expr, ".calculate_unclamped_lod(", sampler_expr, ", ",
  		          to_expression(coord_id), ");");
  		register_control_dependent_expression(id);
  		break;
  	}
  
  #define MSL_ImgQry(qrytype)                                                                 \
  	do                                                                                      \
  	{                                                                                       \
  		uint32_t rslt_type_id = ops[0];                                                     \
  		auto &rslt_type = get<SPIRType>(rslt_type_id);                                      \
  		uint32_t id = ops[1];                                                               \
  		uint32_t img_id = ops[2];                                                           \
  		string img_exp = to_expression(img_id);                                             \
  		string expr = type_to_glsl(rslt_type) + "(" + img_exp + ".get_num_" #qrytype "())"; \
  		emit_op(rslt_type_id, id, expr, should_forward(img_id));                            \
  	} while (false)
  
  	case OpImageQueryLevels:
  		MSL_ImgQry(mip_levels);
  		break;
  
  	case OpImageQuerySamples:
  		MSL_ImgQry(samples);
  		break;
  
  	case OpImage:
  	{
  		uint32_t result_type = ops[0];
  		uint32_t id = ops[1];
  		auto *combined = maybe_get<SPIRCombinedImageSampler>(ops[2]);
  
  		if (combined)
  		{
  			auto &e = emit_op(result_type, id, to_expression(combined->image), true, true);
  			auto *var = maybe_get_backing_variable(combined->image);
  			if (var)
  				e.loaded_from = var->self;
  		}
  		else
  		{
  			auto *var = maybe_get_backing_variable(ops[2]);
  			SPIRExpression *e;
  			if (var && has_extended_decoration(var->self, SPIRVCrossDecorationDynamicImageSampler))
  				e = &emit_op(result_type, id, join(to_expression(ops[2]), ".plane0"), true, true);
  			else
  				e = &emit_op(result_type, id, to_expression(ops[2]), true, true);
  			if (var)
  				e->loaded_from = var->self;
  		}
  		break;
  	}
  
  	// Casting
  	case OpQuantizeToF16:
  	{
  		uint32_t result_type = ops[0];
  		uint32_t id = ops[1];
  		uint32_t arg = ops[2];
  
  		string exp;
  		auto &type = get<SPIRType>(result_type);
  
  		switch (type.vecsize)
  		{
  		case 1:
  			exp = join("float(half(", to_expression(arg), "))");
  			break;
  		case 2:
  			exp = join("float2(half2(", to_expression(arg), "))");
  			break;
  		case 3:
  			exp = join("float3(half3(", to_expression(arg), "))");
  			break;
  		case 4:
  			exp = join("float4(half4(", to_expression(arg), "))");
  			break;
  		default:
  			SPIRV_CROSS_THROW("Illegal argument to OpQuantizeToF16.");
  		}
  
  		emit_op(result_type, id, exp, should_forward(arg));
  		break;
  	}
  
  	case OpInBoundsAccessChain:
  	case OpAccessChain:
  	case OpPtrAccessChain:
  		if (is_tessellation_shader())
  		{
  			if (!emit_tessellation_access_chain(ops, instruction.length))
  				CompilerGLSL::emit_instruction(instruction);
  		}
  		else
  			CompilerGLSL::emit_instruction(instruction);
  		fix_up_interpolant_access_chain(ops, instruction.length);
  		break;
  
  	case OpStore:
  		if (is_out_of_bounds_tessellation_level(ops[0]))
  			break;
  
  		if (maybe_emit_array_assignment(ops[0], ops[1]))
  			break;
  
  		CompilerGLSL::emit_instruction(instruction);
  		break;
  
  	// Compute barriers
  	case OpMemoryBarrier:
  		emit_barrier(0, ops[0], ops[1]);
  		break;
  
  	case OpControlBarrier:
  		// In GLSL a memory barrier is often followed by a control barrier.
  		// But in MSL, memory barriers are also control barriers, so don't
  		// emit a simple control barrier if a memory barrier has just been emitted.
  		if (previous_instruction_opcode != OpMemoryBarrier)
  			emit_barrier(ops[0], ops[1], ops[2]);
  		break;
  
  	case OpOuterProduct:
  	{
  		uint32_t result_type = ops[0];
  		uint32_t id = ops[1];
  		uint32_t a = ops[2];
  		uint32_t b = ops[3];
  
  		auto &type = get<SPIRType>(result_type);
  		string expr = type_to_glsl_constructor(type);
  		expr += "(";
  		for (uint32_t col = 0; col < type.columns; col++)
  		{
  			expr += to_enclosed_expression(a);
  			expr += " * ";
  			expr += to_extract_component_expression(b, col);
  			if (col + 1 < type.columns)
  				expr += ", ";
  		}
  		expr += ")";
  		emit_op(result_type, id, expr, should_forward(a) && should_forward(b));
  		inherit_expression_dependencies(id, a);
  		inherit_expression_dependencies(id, b);
  		break;
  	}
  
  	case OpVectorTimesMatrix:
  	case OpMatrixTimesVector:
  	{
  		if (!msl_options.invariant_float_math && !has_decoration(ops[1], DecorationNoContraction))
  		{
  			CompilerGLSL::emit_instruction(instruction);
  			break;
  		}
  
  		// If the matrix needs transpose, just flip the multiply order.
  		auto *e = maybe_get<SPIRExpression>(ops[opcode == OpMatrixTimesVector ? 2 : 3]);
  		if (e && e->need_transpose)
  		{
  			e->need_transpose = false;
  			string expr;
  
  			if (opcode == OpMatrixTimesVector)
  			{
  				expr = join("spvFMulVectorMatrix(", to_enclosed_unpacked_expression(ops[3]), ", ",
  				            to_unpacked_row_major_matrix_expression(ops[2]), ")");
  			}
  			else
  			{
  				expr = join("spvFMulMatrixVector(", to_unpacked_row_major_matrix_expression(ops[3]), ", ",
  				            to_enclosed_unpacked_expression(ops[2]), ")");
  			}
  
  			bool forward = should_forward(ops[2]) && should_forward(ops[3]);
  			emit_op(ops[0], ops[1], expr, forward);
  			e->need_transpose = true;
  			inherit_expression_dependencies(ops[1], ops[2]);
  			inherit_expression_dependencies(ops[1], ops[3]);
  		}
  		else
  		{
  			if (opcode == OpMatrixTimesVector)
  				MSL_BFOP(spvFMulMatrixVector);
  			else
  				MSL_BFOP(spvFMulVectorMatrix);
  		}
  		break;
  	}
  
  	case OpMatrixTimesMatrix:
  	{
  		if (!msl_options.invariant_float_math && !has_decoration(ops[1], DecorationNoContraction))
  		{
  			CompilerGLSL::emit_instruction(instruction);
  			break;
  		}
  
  		auto *a = maybe_get<SPIRExpression>(ops[2]);
  		auto *b = maybe_get<SPIRExpression>(ops[3]);
  
  		// If both matrices need transpose, we can multiply in flipped order and tag the expression as transposed.
  		// a^T * b^T = (b * a)^T.
  		if (a && b && a->need_transpose && b->need_transpose)
  		{
  			a->need_transpose = false;
  			b->need_transpose = false;
  
  			auto expr =
  			    join("spvFMulMatrixMatrix(", enclose_expression(to_unpacked_row_major_matrix_expression(ops[3])), ", ",
  			         enclose_expression(to_unpacked_row_major_matrix_expression(ops[2])), ")");
  
  			bool forward = should_forward(ops[2]) && should_forward(ops[3]);
  			auto &e = emit_op(ops[0], ops[1], expr, forward);
  			e.need_transpose = true;
  			a->need_transpose = true;
  			b->need_transpose = true;
  			inherit_expression_dependencies(ops[1], ops[2]);
  			inherit_expression_dependencies(ops[1], ops[3]);
  		}
  		else
  			MSL_BFOP(spvFMulMatrixMatrix);
  
  		break;
  	}
  
  	case OpIAddCarry:
  	case OpISubBorrow:
  	{
  		uint32_t result_type = ops[0];
  		uint32_t result_id = ops[1];
  		uint32_t op0 = ops[2];
  		uint32_t op1 = ops[3];
  		auto &type = get<SPIRType>(result_type);
  		emit_uninitialized_temporary_expression(result_type, result_id);
  
  		auto &res_type = get<SPIRType>(type.member_types[1]);
  		if (opcode == OpIAddCarry)
  		{
  			statement(to_expression(result_id), ".", to_member_name(type, 0), " = ", to_enclosed_expression(op0), " + ",
  			          to_enclosed_expression(op1), ";");
  			statement(to_expression(result_id), ".", to_member_name(type, 1), " = select(", type_to_glsl(res_type),
  			          "(1), ", type_to_glsl(res_type), "(0), ", to_expression(result_id), ".", to_member_name(type, 0),
  			          " >= max(", to_expression(op0), ", ", to_expression(op1), "));");
  		}
  		else
  		{
  			statement(to_expression(result_id), ".", to_member_name(type, 0), " = ", to_enclosed_expression(op0), " - ",
  			          to_enclosed_expression(op1), ";");
  			statement(to_expression(result_id), ".", to_member_name(type, 1), " = select(", type_to_glsl(res_type),
  			          "(1), ", type_to_glsl(res_type), "(0), ", to_enclosed_expression(op0),
  			          " >= ", to_enclosed_expression(op1), ");");
  		}
  		break;
  	}
  
  	case OpUMulExtended:
  	case OpSMulExtended:
  	{
  		uint32_t result_type = ops[0];
  		uint32_t result_id = ops[1];
  		uint32_t op0 = ops[2];
  		uint32_t op1 = ops[3];
  		auto &type = get<SPIRType>(result_type);
  		emit_uninitialized_temporary_expression(result_type, result_id);
  
  		statement(to_expression(result_id), ".", to_member_name(type, 0), " = ", to_enclosed_expression(op0), " * ",
  		          to_enclosed_expression(op1), ";");
  		statement(to_expression(result_id), ".", to_member_name(type, 1), " = mulhi(", to_expression(op0), ", ",
  		          to_expression(op1), ");");
  		break;
  	}
  
  	case OpArrayLength:
  	{
  		auto &type = expression_type(ops[2]);
  		uint32_t offset = type_struct_member_offset(type, ops[3]);
  		uint32_t stride = type_struct_member_array_stride(type, ops[3]);
  
  		auto expr = join("(", to_buffer_size_expression(ops[2]), " - ", offset, ") / ", stride);
  		emit_op(ops[0], ops[1], expr, true);
  		break;
  	}
  
  	// SPV_INTEL_shader_integer_functions2
  	case OpUCountLeadingZerosINTEL:
  		MSL_UFOP(clz);
  		break;
  
  	case OpUCountTrailingZerosINTEL:
  		MSL_UFOP(ctz);
  		break;
  
  	case OpAbsISubINTEL:
  	case OpAbsUSubINTEL:
  		MSL_BFOP(absdiff);
  		break;
  
  	case OpIAddSatINTEL:
  	case OpUAddSatINTEL:
  		MSL_BFOP(addsat);
  		break;
  
  	case OpIAverageINTEL:
  	case OpUAverageINTEL:
  		MSL_BFOP(hadd);
  		break;
  
  	case OpIAverageRoundedINTEL:
  	case OpUAverageRoundedINTEL:
  		MSL_BFOP(rhadd);
  		break;
  
  	case OpISubSatINTEL:
  	case OpUSubSatINTEL:
  		MSL_BFOP(subsat);
  		break;
  
  	case OpIMul32x16INTEL:
  	{
  		uint32_t result_type = ops[0];
  		uint32_t id = ops[1];
  		uint32_t a = ops[2], b = ops[3];
  		bool forward = should_forward(a) && should_forward(b);
  		emit_op(result_type, id, join("int(short(", to_expression(a), ")) * int(short(", to_expression(b), "))"),
  		        forward);
  		inherit_expression_dependencies(id, a);
  		inherit_expression_dependencies(id, b);
  		break;
  	}
  
  	case OpUMul32x16INTEL:
  	{
  		uint32_t result_type = ops[0];
  		uint32_t id = ops[1];
  		uint32_t a = ops[2], b = ops[3];
  		bool forward = should_forward(a) && should_forward(b);
  		emit_op(result_type, id, join("uint(ushort(", to_expression(a), ")) * uint(ushort(", to_expression(b), "))"),
  		        forward);
  		inherit_expression_dependencies(id, a);
  		inherit_expression_dependencies(id, b);
  		break;
  	}
  
  	// SPV_EXT_demote_to_helper_invocation
  	case OpDemoteToHelperInvocationEXT:
  		if (!msl_options.supports_msl_version(2, 3))
  			SPIRV_CROSS_THROW("discard_fragment() does not formally have demote semantics until MSL 2.3.");
  		CompilerGLSL::emit_instruction(instruction);
  		break;
  
  	case OpIsHelperInvocationEXT:
  		if (msl_options.is_ios() && !msl_options.supports_msl_version(2, 3))
  			SPIRV_CROSS_THROW("simd_is_helper_thread() requires MSL 2.3 on iOS.");
  		else if (msl_options.is_macos() && !msl_options.supports_msl_version(2, 1))
  			SPIRV_CROSS_THROW("simd_is_helper_thread() requires MSL 2.1 on macOS.");
  		emit_op(ops[0], ops[1], "simd_is_helper_thread()", false);
  		break;
  
  	case OpBeginInvocationInterlockEXT:
  	case OpEndInvocationInterlockEXT:
  		if (!msl_options.supports_msl_version(2, 0))
  			SPIRV_CROSS_THROW("Raster order groups require MSL 2.0.");
  		break; // Nothing to do in the body
  
  	default:
  		CompilerGLSL::emit_instruction(instruction);
  		break;
  	}
  
  	previous_instruction_opcode = opcode;
  }
  
  void CompilerMSL::emit_texture_op(const Instruction &i, bool sparse)
  {
  	if (sparse)
  		SPIRV_CROSS_THROW("Sparse feedback not yet supported in MSL.");
  
  	if (msl_options.use_framebuffer_fetch_subpasses)
  	{
  		auto *ops = stream(i);
  
  		uint32_t result_type_id = ops[0];
  		uint32_t id = ops[1];
  		uint32_t img = ops[2];
  
  		auto &type = expression_type(img);
  		auto &imgtype = get<SPIRType>(type.self);
  
  		// Use Metal's native frame-buffer fetch API for subpass inputs.
  		if (imgtype.image.dim == DimSubpassData)
  		{
  			// Subpass inputs cannot be invalidated,
  			// so just forward the expression directly.
  			string expr = to_expression(img);
  			emit_op(result_type_id, id, expr, true);
  			return;
  		}
  	}
  
  	// Fallback to default implementation
  	CompilerGLSL::emit_texture_op(i, sparse);
  }
  
  void CompilerMSL::emit_barrier(uint32_t id_exe_scope, uint32_t id_mem_scope, uint32_t id_mem_sem)
  {
  	if (get_execution_model() != ExecutionModelGLCompute && get_execution_model() != ExecutionModelTessellationControl)
  		return;
  
  	uint32_t exe_scope = id_exe_scope ? evaluate_constant_u32(id_exe_scope) : uint32_t(ScopeInvocation);
  	uint32_t mem_scope = id_mem_scope ? evaluate_constant_u32(id_mem_scope) : uint32_t(ScopeInvocation);
  	// Use the wider of the two scopes (smaller value)
  	exe_scope = min(exe_scope, mem_scope);
  
  	if (msl_options.emulate_subgroups && exe_scope >= ScopeSubgroup && !id_mem_sem)
  		// In this case, we assume a "subgroup" size of 1. The barrier, then, is a noop.
  		return;
  
  	string bar_stmt;
  	if ((msl_options.is_ios() && msl_options.supports_msl_version(1, 2)) || msl_options.supports_msl_version(2))
  		bar_stmt = exe_scope < ScopeSubgroup ? "threadgroup_barrier" : "simdgroup_barrier";
  	else
  		bar_stmt = "threadgroup_barrier";
  	bar_stmt += "(";
  
  	uint32_t mem_sem = id_mem_sem ? evaluate_constant_u32(id_mem_sem) : uint32_t(MemorySemanticsMaskNone);
  
  	// Use the | operator to combine flags if we can.
  	if (msl_options.supports_msl_version(1, 2))
  	{
  		string mem_flags = "";
  		// For tesc shaders, this also affects objects in the Output storage class.
  		// Since in Metal, these are placed in a device buffer, we have to sync device memory here.
  		if (get_execution_model() == ExecutionModelTessellationControl ||
  		    (mem_sem & (MemorySemanticsUniformMemoryMask | MemorySemanticsCrossWorkgroupMemoryMask)))
  			mem_flags += "mem_flags::mem_device";
  
  		// Fix tessellation patch function processing
  		if (get_execution_model() == ExecutionModelTessellationControl ||
  		    (mem_sem & (MemorySemanticsSubgroupMemoryMask | MemorySemanticsWorkgroupMemoryMask)))
  		{
  			if (!mem_flags.empty())
  				mem_flags += " | ";
  			mem_flags += "mem_flags::mem_threadgroup";
  		}
  		if (mem_sem & MemorySemanticsImageMemoryMask)
  		{
  			if (!mem_flags.empty())
  				mem_flags += " | ";
  			mem_flags += "mem_flags::mem_texture";
  		}
  
  		if (mem_flags.empty())
  			mem_flags = "mem_flags::mem_none";
  
  		bar_stmt += mem_flags;
  	}
  	else
  	{
  		if ((mem_sem & (MemorySemanticsUniformMemoryMask | MemorySemanticsCrossWorkgroupMemoryMask)) &&
  		    (mem_sem & (MemorySemanticsSubgroupMemoryMask | MemorySemanticsWorkgroupMemoryMask)))
  			bar_stmt += "mem_flags::mem_device_and_threadgroup";
  		else if (mem_sem & (MemorySemanticsUniformMemoryMask | MemorySemanticsCrossWorkgroupMemoryMask))
  			bar_stmt += "mem_flags::mem_device";
  		else if (mem_sem & (MemorySemanticsSubgroupMemoryMask | MemorySemanticsWorkgroupMemoryMask))
  			bar_stmt += "mem_flags::mem_threadgroup";
  		else if (mem_sem & MemorySemanticsImageMemoryMask)
  			bar_stmt += "mem_flags::mem_texture";
  		else
  			bar_stmt += "mem_flags::mem_none";
  	}
  
  	bar_stmt += ");";
  
  	statement(bar_stmt);
  
  	assert(current_emitting_block);
  	flush_control_dependent_expressions(current_emitting_block->self);
  	flush_all_active_variables();
  }
  
  static bool storage_class_array_is_thread(StorageClass storage)
  {
  	switch (storage)
  	{
  	case StorageClassInput:
  	case StorageClassOutput:
  	case StorageClassGeneric:
  	case StorageClassFunction:
  	case StorageClassPrivate:
  		return true;
  
  	default:
  		return false;
  	}
  }
  
  void CompilerMSL::emit_array_copy(const string &lhs, uint32_t lhs_id, uint32_t rhs_id,
  								  StorageClass lhs_storage, StorageClass rhs_storage)
  {
  	// Allow Metal to use the array<T> template to make arrays a value type.
  	// This, however, cannot be used for threadgroup address specifiers, so consider the custom array copy as fallback.
  	bool lhs_is_thread_storage = storage_class_array_is_thread(lhs_storage);
  	bool rhs_is_thread_storage = storage_class_array_is_thread(rhs_storage);
  
  	bool lhs_is_array_template = lhs_is_thread_storage;
  	bool rhs_is_array_template = rhs_is_thread_storage;
  
  	// Special considerations for stage IO variables.
  	// If the variable is actually backed by non-user visible device storage, we use array templates for those.
  	//
  	// Another special consideration is given to thread local variables which happen to have Offset decorations
  	// applied to them. Block-like types do not use array templates, so we need to force POD path if we detect
  	// these scenarios. This check isn't perfect since it would be technically possible to mix and match these things,
  	// and for a fully correct solution we might have to track array template state through access chains as well,
  	// but for all reasonable use cases, this should suffice.
  	// This special case should also only apply to Function/Private storage classes.
  	// We should not check backing variable for temporaries.
  	auto *lhs_var = maybe_get_backing_variable(lhs_id);
  	if (lhs_var && lhs_storage == StorageClassStorageBuffer && storage_class_array_is_thread(lhs_var->storage))
  		lhs_is_array_template = true;
  	else if (lhs_var && (lhs_storage == StorageClassFunction || lhs_storage == StorageClassPrivate) &&
  	         type_is_block_like(get<SPIRType>(lhs_var->basetype)))
  		lhs_is_array_template = false;
  
  	auto *rhs_var = maybe_get_backing_variable(rhs_id);
  	if (rhs_var && rhs_storage == StorageClassStorageBuffer && storage_class_array_is_thread(rhs_var->storage))
  		rhs_is_array_template = true;
  	else if (rhs_var && (rhs_storage == StorageClassFunction || rhs_storage == StorageClassPrivate) &&
  	         type_is_block_like(get<SPIRType>(rhs_var->basetype)))
  		rhs_is_array_template = false;
  
  	// If threadgroup storage qualifiers are *not* used:
  	// Avoid spvCopy* wrapper functions; Otherwise, spvUnsafeArray<> template cannot be used with that storage qualifier.
  	if (lhs_is_array_template && rhs_is_array_template && !using_builtin_array())
  	{
  		statement(lhs, " = ", to_expression(rhs_id), ";");
  	}
  	else
  	{
  		// Assignment from an array initializer is fine.
  		auto &type = expression_type(rhs_id);
  		auto *var = maybe_get_backing_variable(rhs_id);
  
  		// Unfortunately, we cannot template on address space in MSL,
  		// so explicit address space redirection it is ...
  		bool is_constant = false;
  		if (ir.ids[rhs_id].get_type() == TypeConstant)
  		{
  			is_constant = true;
  		}
  		else if (var && var->remapped_variable && var->statically_assigned &&
  		         ir.ids[var->static_expression].get_type() == TypeConstant)
  		{
  			is_constant = true;
  		}
  		else if (rhs_storage == StorageClassUniform)
  		{
  			is_constant = true;
  		}
  
  		// For the case where we have OpLoad triggering an array copy,
  		// we cannot easily detect this case ahead of time since it's
  		// context dependent. We might have to force a recompile here
  		// if this is the only use of array copies in our shader.
  		if (type.array.size() > 1)
  		{
  			if (type.array.size() > kArrayCopyMultidimMax)
  				SPIRV_CROSS_THROW("Cannot support this many dimensions for arrays of arrays.");
  			auto func = static_cast<SPVFuncImpl>(SPVFuncImplArrayCopyMultidimBase + type.array.size());
  			add_spv_func_and_recompile(func);
  		}
  		else
  			add_spv_func_and_recompile(SPVFuncImplArrayCopy);
  
  		const char *tag = nullptr;
  		if (lhs_is_thread_storage && is_constant)
  			tag = "FromConstantToStack";
  		else if (lhs_storage == StorageClassWorkgroup && is_constant)
  			tag = "FromConstantToThreadGroup";
  		else if (lhs_is_thread_storage && rhs_is_thread_storage)
  			tag = "FromStackToStack";
  		else if (lhs_storage == StorageClassWorkgroup && rhs_is_thread_storage)
  			tag = "FromStackToThreadGroup";
  		else if (lhs_is_thread_storage && rhs_storage == StorageClassWorkgroup)
  			tag = "FromThreadGroupToStack";
  		else if (lhs_storage == StorageClassWorkgroup && rhs_storage == StorageClassWorkgroup)
  			tag = "FromThreadGroupToThreadGroup";
  		else if (lhs_storage == StorageClassStorageBuffer && rhs_storage == StorageClassStorageBuffer)
  			tag = "FromDeviceToDevice";
  		else if (lhs_storage == StorageClassStorageBuffer && is_constant)
  			tag = "FromConstantToDevice";
  		else if (lhs_storage == StorageClassStorageBuffer && rhs_storage == StorageClassWorkgroup)
  			tag = "FromThreadGroupToDevice";
  		else if (lhs_storage == StorageClassStorageBuffer && rhs_is_thread_storage)
  			tag = "FromStackToDevice";
  		else if (lhs_storage == StorageClassWorkgroup && rhs_storage == StorageClassStorageBuffer)
  			tag = "FromDeviceToThreadGroup";
  		else if (lhs_is_thread_storage && rhs_storage == StorageClassStorageBuffer)
  			tag = "FromDeviceToStack";
  		else
  			SPIRV_CROSS_THROW("Unknown storage class used for copying arrays.");
  
  		// Pass internal array of spvUnsafeArray<> into wrapper functions
  		if (lhs_is_array_template && rhs_is_array_template && !msl_options.force_native_arrays)
  			statement("spvArrayCopy", tag, type.array.size(), "(", lhs, ".elements, ", to_expression(rhs_id), ".elements);");
  		if (lhs_is_array_template && !msl_options.force_native_arrays)
  			statement("spvArrayCopy", tag, type.array.size(), "(", lhs, ".elements, ", to_expression(rhs_id), ");");
  		else if (rhs_is_array_template && !msl_options.force_native_arrays)
  			statement("spvArrayCopy", tag, type.array.size(), "(", lhs, ", ", to_expression(rhs_id), ".elements);");
  		else
  			statement("spvArrayCopy", tag, type.array.size(), "(", lhs, ", ", to_expression(rhs_id), ");");
  	}
  }
  
  uint32_t CompilerMSL::get_physical_tess_level_array_size(spv::BuiltIn builtin) const
  {
  	if (get_execution_mode_bitset().get(ExecutionModeTriangles))
  		return builtin == BuiltInTessLevelInner ? 1 : 3;
  	else
  		return builtin == BuiltInTessLevelInner ? 2 : 4;
  }
  
  // Since MSL does not allow arrays to be copied via simple variable assignment,
  // if the LHS and RHS represent an assignment of an entire array, it must be
  // implemented by calling an array copy function.
  // Returns whether the struct assignment was emitted.
  bool CompilerMSL::maybe_emit_array_assignment(uint32_t id_lhs, uint32_t id_rhs)
  {
  	// We only care about assignments of an entire array
  	auto &type = expression_type(id_rhs);
  	if (type.array.size() == 0)
  		return false;
  
  	auto *var = maybe_get<SPIRVariable>(id_lhs);
  
  	// Is this a remapped, static constant? Don't do anything.
  	if (var && var->remapped_variable && var->statically_assigned)
  		return true;
  
  	if (ir.ids[id_rhs].get_type() == TypeConstant && var && var->deferred_declaration)
  	{
  		// Special case, if we end up declaring a variable when assigning the constant array,
  		// we can avoid the copy by directly assigning the constant expression.
  		// This is likely necessary to be able to use a variable as a true look-up table, as it is unlikely
  		// the compiler will be able to optimize the spvArrayCopy() into a constant LUT.
  		// After a variable has been declared, we can no longer assign constant arrays in MSL unfortunately.
  		statement(to_expression(id_lhs), " = ", constant_expression(get<SPIRConstant>(id_rhs)), ";");
  		return true;
  	}
  
  	if (get_execution_model() == ExecutionModelTessellationControl &&
  	    has_decoration(id_lhs, DecorationBuiltIn))
  	{
  		auto builtin = BuiltIn(get_decoration(id_lhs, DecorationBuiltIn));
  		// Need to manually unroll the array store.
  		if (builtin == BuiltInTessLevelInner || builtin == BuiltInTessLevelOuter)
  		{
  			uint32_t array_size = get_physical_tess_level_array_size(builtin);
  			if (array_size == 1)
  				statement(to_expression(id_lhs), " = half(", to_expression(id_rhs), "[0]);");
  			else
  			{
  				for (uint32_t i = 0; i < array_size; i++)
  					statement(to_expression(id_lhs), "[", i, "] = half(", to_expression(id_rhs), "[", i, "]);");
  			}
  			return true;
  		}
  	}
  
  	// Ensure the LHS variable has been declared
  	auto *p_v_lhs = maybe_get_backing_variable(id_lhs);
  	if (p_v_lhs)
  		flush_variable_declaration(p_v_lhs->self);
  
  	auto lhs_storage = get_expression_effective_storage_class(id_lhs);
  	auto rhs_storage = get_expression_effective_storage_class(id_rhs);
  	emit_array_copy(to_expression(id_lhs), id_lhs, id_rhs, lhs_storage, rhs_storage);
  	register_write(id_lhs);
  
  	return true;
  }
  
  // Emits one of the atomic functions. In MSL, the atomic functions operate on pointers
  void CompilerMSL::emit_atomic_func_op(uint32_t result_type, uint32_t result_id, const char *op, uint32_t mem_order_1,
                                        uint32_t mem_order_2, bool has_mem_order_2, uint32_t obj, uint32_t op1,
                                        bool op1_is_pointer, bool op1_is_literal, uint32_t op2)
  {
  	string exp = string(op) + "(";
  
  	auto &type = get_pointee_type(expression_type(obj));
  	exp += "(";
  	auto *var = maybe_get_backing_variable(obj);
  	if (!var)
  		SPIRV_CROSS_THROW("No backing variable for atomic operation.");
  
  	// Emulate texture2D atomic operations
  	const auto &res_type = get<SPIRType>(var->basetype);
  	if (res_type.storage == StorageClassUniformConstant && res_type.basetype == SPIRType::Image)
  	{
  		exp += "device";
  	}
  	else
  	{
  		exp += get_argument_address_space(*var);
  	}
  
  	exp += " atomic_";
  	exp += type_to_glsl(type);
  	exp += "*)";
  
  	exp += "&";
  	exp += to_enclosed_expression(obj);
  
  	bool is_atomic_compare_exchange_strong = op1_is_pointer && op1;
  
  	if (is_atomic_compare_exchange_strong)
  	{
  		assert(strcmp(op, "atomic_compare_exchange_weak_explicit") == 0);
  		assert(op2);
  		assert(has_mem_order_2);
  		exp += ", &";
  		exp += to_name(result_id);
  		exp += ", ";
  		exp += to_expression(op2);
  		exp += ", ";
  		exp += get_memory_order(mem_order_1);
  		exp += ", ";
  		exp += get_memory_order(mem_order_2);
  		exp += ")";
  
  		// MSL only supports the weak atomic compare exchange, so emit a CAS loop here.
  		// The MSL function returns false if the atomic write fails OR the comparison test fails,
  		// so we must validate that it wasn't the comparison test that failed before continuing
  		// the CAS loop, otherwise it will loop infinitely, with the comparison test always failing.
  		// The function updates the comparitor value from the memory value, so the additional
  		// comparison test evaluates the memory value against the expected value.
  		emit_uninitialized_temporary_expression(result_type, result_id);
  		statement("do");
  		begin_scope();
  		statement(to_name(result_id), " = ", to_expression(op1), ";");
  		end_scope_decl(join("while (!", exp, " && ", to_name(result_id), " == ", to_enclosed_expression(op1), ")"));
  	}
  	else
  	{
  		assert(strcmp(op, "atomic_compare_exchange_weak_explicit") != 0);
  		if (op1)
  		{
  			if (op1_is_literal)
  				exp += join(", ", op1);
  			else
  				exp += ", " + to_expression(op1);
  		}
  		if (op2)
  			exp += ", " + to_expression(op2);
  
  		exp += string(", ") + get_memory_order(mem_order_1);
  		if (has_mem_order_2)
  			exp += string(", ") + get_memory_order(mem_order_2);
  
  		exp += ")";
  
  		if (strcmp(op, "atomic_store_explicit") != 0)
  			emit_op(result_type, result_id, exp, false);
  		else
  			statement(exp, ";");
  	}
  
  	flush_all_atomic_capable_variables();
  }
  
  // Metal only supports relaxed memory order for now
  const char *CompilerMSL::get_memory_order(uint32_t)
  {
  	return "memory_order_relaxed";
  }
  
  // Override for MSL-specific extension syntax instructions
  void CompilerMSL::emit_glsl_op(uint32_t result_type, uint32_t id, uint32_t eop, const uint32_t *args, uint32_t count)
  {
  	auto op = static_cast<GLSLstd450>(eop);
  
  	// If we need to do implicit bitcasts, make sure we do it with the correct type.
  	uint32_t integer_width = get_integer_width_for_glsl_instruction(op, args, count);
  	auto int_type = to_signed_basetype(integer_width);
  	auto uint_type = to_unsigned_basetype(integer_width);
  
  	switch (op)
  	{
  	case GLSLstd450Atan2:
  		emit_binary_func_op(result_type, id, args[0], args[1], "atan2");
  		break;
  	case GLSLstd450InverseSqrt:
  		emit_unary_func_op(result_type, id, args[0], "rsqrt");
  		break;
  	case GLSLstd450RoundEven:
  		emit_unary_func_op(result_type, id, args[0], "rint");
  		break;
  
  	case GLSLstd450FindILsb:
  	{
  		// In this template version of findLSB, we return T.
  		auto basetype = expression_type(args[0]).basetype;
  		emit_unary_func_op_cast(result_type, id, args[0], "spvFindLSB", basetype, basetype);
  		break;
  	}
  
  	case GLSLstd450FindSMsb:
  		emit_unary_func_op_cast(result_type, id, args[0], "spvFindSMSB", int_type, int_type);
  		break;
  
  	case GLSLstd450FindUMsb:
  		emit_unary_func_op_cast(result_type, id, args[0], "spvFindUMSB", uint_type, uint_type);
  		break;
  
  	case GLSLstd450PackSnorm4x8:
  		emit_unary_func_op(result_type, id, args[0], "pack_float_to_snorm4x8");
  		break;
  	case GLSLstd450PackUnorm4x8:
  		emit_unary_func_op(result_type, id, args[0], "pack_float_to_unorm4x8");
  		break;
  	case GLSLstd450PackSnorm2x16:
  		emit_unary_func_op(result_type, id, args[0], "pack_float_to_snorm2x16");
  		break;
  	case GLSLstd450PackUnorm2x16:
  		emit_unary_func_op(result_type, id, args[0], "pack_float_to_unorm2x16");
  		break;
  
  	case GLSLstd450PackHalf2x16:
  	{
  		auto expr = join("as_type<uint>(half2(", to_expression(args[0]), "))");
  		emit_op(result_type, id, expr, should_forward(args[0]));
  		inherit_expression_dependencies(id, args[0]);
  		break;
  	}
  
  	case GLSLstd450UnpackSnorm4x8:
  		emit_unary_func_op(result_type, id, args[0], "unpack_snorm4x8_to_float");
  		break;
  	case GLSLstd450UnpackUnorm4x8:
  		emit_unary_func_op(result_type, id, args[0], "unpack_unorm4x8_to_float");
  		break;
  	case GLSLstd450UnpackSnorm2x16:
  		emit_unary_func_op(result_type, id, args[0], "unpack_snorm2x16_to_float");
  		break;
  	case GLSLstd450UnpackUnorm2x16:
  		emit_unary_func_op(result_type, id, args[0], "unpack_unorm2x16_to_float");
  		break;
  
  	case GLSLstd450UnpackHalf2x16:
  	{
  		auto expr = join("float2(as_type<half2>(", to_expression(args[0]), "))");
  		emit_op(result_type, id, expr, should_forward(args[0]));
  		inherit_expression_dependencies(id, args[0]);
  		break;
  	}
  
  	case GLSLstd450PackDouble2x32:
  		emit_unary_func_op(result_type, id, args[0], "unsupported_GLSLstd450PackDouble2x32"); // Currently unsupported
  		break;
  	case GLSLstd450UnpackDouble2x32:
  		emit_unary_func_op(result_type, id, args[0], "unsupported_GLSLstd450UnpackDouble2x32"); // Currently unsupported
  		break;
  
  	case GLSLstd450MatrixInverse:
  	{
  		auto &mat_type = get<SPIRType>(result_type);
  		switch (mat_type.columns)
  		{
  		case 2:
  			emit_unary_func_op(result_type, id, args[0], "spvInverse2x2");
  			break;
  		case 3:
  			emit_unary_func_op(result_type, id, args[0], "spvInverse3x3");
  			break;
  		case 4:
  			emit_unary_func_op(result_type, id, args[0], "spvInverse4x4");
  			break;
  		default:
  			break;
  		}
  		break;
  	}
  
  	case GLSLstd450FMin:
  		// If the result type isn't float, don't bother calling the specific
  		// precise::/fast:: version. Metal doesn't have those for half and
  		// double types.
  		if (get<SPIRType>(result_type).basetype != SPIRType::Float)
  			emit_binary_func_op(result_type, id, args[0], args[1], "min");
  		else
  			emit_binary_func_op(result_type, id, args[0], args[1], "fast::min");
  		break;
  
  	case GLSLstd450FMax:
  		if (get<SPIRType>(result_type).basetype != SPIRType::Float)
  			emit_binary_func_op(result_type, id, args[0], args[1], "max");
  		else
  			emit_binary_func_op(result_type, id, args[0], args[1], "fast::max");
  		break;
  
  	case GLSLstd450FClamp:
  		// TODO: If args[1] is 0 and args[2] is 1, emit a saturate() call.
  		if (get<SPIRType>(result_type).basetype != SPIRType::Float)
  			emit_trinary_func_op(result_type, id, args[0], args[1], args[2], "clamp");
  		else
  			emit_trinary_func_op(result_type, id, args[0], args[1], args[2], "fast::clamp");
  		break;
  
  	case GLSLstd450NMin:
  		if (get<SPIRType>(result_type).basetype != SPIRType::Float)
  			emit_binary_func_op(result_type, id, args[0], args[1], "min");
  		else
  			emit_binary_func_op(result_type, id, args[0], args[1], "precise::min");
  		break;
  
  	case GLSLstd450NMax:
  		if (get<SPIRType>(result_type).basetype != SPIRType::Float)
  			emit_binary_func_op(result_type, id, args[0], args[1], "max");
  		else
  			emit_binary_func_op(result_type, id, args[0], args[1], "precise::max");
  		break;
  
  	case GLSLstd450NClamp:
  		// TODO: If args[1] is 0 and args[2] is 1, emit a saturate() call.
  		if (get<SPIRType>(result_type).basetype != SPIRType::Float)
  			emit_trinary_func_op(result_type, id, args[0], args[1], args[2], "clamp");
  		else
  			emit_trinary_func_op(result_type, id, args[0], args[1], args[2], "precise::clamp");
  		break;
  
  	case GLSLstd450InterpolateAtCentroid:
  	{
  		// We can't just emit the expression normally, because the qualified name contains a call to the default
  		// interpolate method, or refers to a local variable. We saved the interface index we need; use it to construct
  		// the base for the method call.
  		uint32_t interface_index = get_extended_decoration(args[0], SPIRVCrossDecorationInterfaceMemberIndex);
  		string component;
  		if (has_extended_decoration(args[0], SPIRVCrossDecorationInterpolantComponentExpr))
  		{
  			uint32_t index_expr = get_extended_decoration(args[0], SPIRVCrossDecorationInterpolantComponentExpr);
  			auto *c = maybe_get<SPIRConstant>(index_expr);
  			if (!c || c->specialization)
  				component = join("[", to_expression(index_expr), "]");
  			else
  				component = join(".", index_to_swizzle(c->scalar()));
  		}
  		emit_op(result_type, id,
  		        join(to_name(stage_in_var_id), ".", to_member_name(get_stage_in_struct_type(), interface_index),
  		             ".interpolate_at_centroid()", component),
  		        should_forward(args[0]));
  		break;
  	}
  
  	case GLSLstd450InterpolateAtSample:
  	{
  		uint32_t interface_index = get_extended_decoration(args[0], SPIRVCrossDecorationInterfaceMemberIndex);
  		string component;
  		if (has_extended_decoration(args[0], SPIRVCrossDecorationInterpolantComponentExpr))
  		{
  			uint32_t index_expr = get_extended_decoration(args[0], SPIRVCrossDecorationInterpolantComponentExpr);
  			auto *c = maybe_get<SPIRConstant>(index_expr);
  			if (!c || c->specialization)
  				component = join("[", to_expression(index_expr), "]");
  			else
  				component = join(".", index_to_swizzle(c->scalar()));
  		}
  		emit_op(result_type, id,
  		        join(to_name(stage_in_var_id), ".", to_member_name(get_stage_in_struct_type(), interface_index),
  		             ".interpolate_at_sample(", to_expression(args[1]), ")", component),
  		        should_forward(args[0]) && should_forward(args[1]));
  		break;
  	}
  
  	case GLSLstd450InterpolateAtOffset:
  	{
  		uint32_t interface_index = get_extended_decoration(args[0], SPIRVCrossDecorationInterfaceMemberIndex);
  		string component;
  		if (has_extended_decoration(args[0], SPIRVCrossDecorationInterpolantComponentExpr))
  		{
  			uint32_t index_expr = get_extended_decoration(args[0], SPIRVCrossDecorationInterpolantComponentExpr);
  			auto *c = maybe_get<SPIRConstant>(index_expr);
  			if (!c || c->specialization)
  				component = join("[", to_expression(index_expr), "]");
  			else
  				component = join(".", index_to_swizzle(c->scalar()));
  		}
  		// Like Direct3D, Metal puts the (0, 0) at the upper-left corner, not the center as SPIR-V and GLSL do.
  		// Offset the offset by (1/2 - 1/16), or 0.4375, to compensate for this.
  		// It has to be (1/2 - 1/16) and not 1/2, or several CTS tests subtly break on Intel.
  		emit_op(result_type, id,
  		        join(to_name(stage_in_var_id), ".", to_member_name(get_stage_in_struct_type(), interface_index),
  		             ".interpolate_at_offset(", to_expression(args[1]), " + 0.4375)", component),
  		        should_forward(args[0]) && should_forward(args[1]));
  		break;
  	}
  
  	case GLSLstd450Distance:
  		// MSL does not support scalar versions here.
  		if (expression_type(args[0]).vecsize == 1)
  		{
  			// Equivalent to length(a - b) -> abs(a - b).
  			emit_op(result_type, id,
  			        join("abs(", to_enclosed_unpacked_expression(args[0]), " - ",
  			             to_enclosed_unpacked_expression(args[1]), ")"),
  			        should_forward(args[0]) && should_forward(args[1]));
  			inherit_expression_dependencies(id, args[0]);
  			inherit_expression_dependencies(id, args[1]);
  		}
  		else
  			CompilerGLSL::emit_glsl_op(result_type, id, eop, args, count);
  		break;
  
  	case GLSLstd450Length:
  		// MSL does not support scalar versions here.
  		if (expression_type(args[0]).vecsize == 1)
  		{
  			// Equivalent to abs().
  			emit_unary_func_op(result_type, id, args[0], "abs");
  		}
  		else
  			CompilerGLSL::emit_glsl_op(result_type, id, eop, args, count);
  		break;
  
  	case GLSLstd450Normalize:
  		// MSL does not support scalar versions here.
  		if (expression_type(args[0]).vecsize == 1)
  		{
  			// Returns -1 or 1 for valid input, sign() does the job.
  			emit_unary_func_op(result_type, id, args[0], "sign");
  		}
  		else
  			CompilerGLSL::emit_glsl_op(result_type, id, eop, args, count);
  		break;
  
  	case GLSLstd450Reflect:
  		if (get<SPIRType>(result_type).vecsize == 1)
  			emit_binary_func_op(result_type, id, args[0], args[1], "spvReflect");
  		else
  			CompilerGLSL::emit_glsl_op(result_type, id, eop, args, count);
  		break;
  
  	case GLSLstd450Refract:
  		if (get<SPIRType>(result_type).vecsize == 1)
  			emit_trinary_func_op(result_type, id, args[0], args[1], args[2], "spvRefract");
  		else
  			CompilerGLSL::emit_glsl_op(result_type, id, eop, args, count);
  		break;
  
  	case GLSLstd450FaceForward:
  		if (get<SPIRType>(result_type).vecsize == 1)
  			emit_trinary_func_op(result_type, id, args[0], args[1], args[2], "spvFaceForward");
  		else
  			CompilerGLSL::emit_glsl_op(result_type, id, eop, args, count);
  		break;
  
  	case GLSLstd450Modf:
  	case GLSLstd450Frexp:
  	{
  		// Special case. If the variable is a scalar access chain, we cannot use it directly. We have to emit a temporary.
  		auto *ptr = maybe_get<SPIRExpression>(args[1]);
  		if (ptr && ptr->access_chain && is_scalar(expression_type(args[1])))
  		{
  			register_call_out_argument(args[1]);
  			forced_temporaries.insert(id);
  
  			// Need to create temporaries and copy over to access chain after.
  			// We cannot directly take the reference of a vector swizzle in MSL, even if it's scalar ...
  			uint32_t &tmp_id = extra_sub_expressions[id];
  			if (!tmp_id)
  				tmp_id = ir.increase_bound_by(1);
  
  			uint32_t tmp_type_id = get_pointee_type_id(ptr->expression_type);
  			emit_uninitialized_temporary_expression(tmp_type_id, tmp_id);
  			emit_binary_func_op(result_type, id, args[0], tmp_id, eop == GLSLstd450Modf ? "modf" : "frexp");
  			statement(to_expression(args[1]), " = ", to_expression(tmp_id), ";");
  		}
  		else
  			CompilerGLSL::emit_glsl_op(result_type, id, eop, args, count);
  		break;
  	}
  
  	default:
  		CompilerGLSL::emit_glsl_op(result_type, id, eop, args, count);
  		break;
  	}
  }
  
  void CompilerMSL::emit_spv_amd_shader_trinary_minmax_op(uint32_t result_type, uint32_t id, uint32_t eop,
                                                          const uint32_t *args, uint32_t count)
  {
  	enum AMDShaderTrinaryMinMax
  	{
  		FMin3AMD = 1,
  		UMin3AMD = 2,
  		SMin3AMD = 3,
  		FMax3AMD = 4,
  		UMax3AMD = 5,
  		SMax3AMD = 6,
  		FMid3AMD = 7,
  		UMid3AMD = 8,
  		SMid3AMD = 9
  	};
  
  	if (!msl_options.supports_msl_version(2, 1))
  		SPIRV_CROSS_THROW("Trinary min/max functions require MSL 2.1.");
  
  	auto op = static_cast<AMDShaderTrinaryMinMax>(eop);
  
  	switch (op)
  	{
  	case FMid3AMD:
  	case UMid3AMD:
  	case SMid3AMD:
  		emit_trinary_func_op(result_type, id, args[0], args[1], args[2], "median3");
  		break;
  	default:
  		CompilerGLSL::emit_spv_amd_shader_trinary_minmax_op(result_type, id, eop, args, count);
  		break;
  	}
  }
  
  // Emit a structure declaration for the specified interface variable.
  void CompilerMSL::emit_interface_block(uint32_t ib_var_id)
  {
  	if (ib_var_id)
  	{
  		auto &ib_var = get<SPIRVariable>(ib_var_id);
  		auto &ib_type = get_variable_data_type(ib_var);
  		//assert(ib_type.basetype == SPIRType::Struct && !ib_type.member_types.empty());
  		assert(ib_type.basetype == SPIRType::Struct);
  		emit_struct(ib_type);
  	}
  }
  
  // Emits the declaration signature of the specified function.
  // If this is the entry point function, Metal-specific return value and function arguments are added.
  void CompilerMSL::emit_function_prototype(SPIRFunction &func, const Bitset &)
  {
  	if (func.self != ir.default_entry_point)
  		add_function_overload(func);
  
  	local_variable_names = resource_names;
  	string decl;
  
  	processing_entry_point = func.self == ir.default_entry_point;
  
  	// Metal helper functions must be static force-inline otherwise they will cause problems when linked together in a single Metallib.
  	if (!processing_entry_point)
  		statement(force_inline);
  
  	auto &type = get<SPIRType>(func.return_type);
  
  	if (!type.array.empty() && msl_options.force_native_arrays)
  	{
  		// We cannot return native arrays in MSL, so "return" through an out variable.
  		decl += "void";
  	}
  	else
  	{
  		decl += func_type_decl(type);
  	}
  
  	decl += " ";
  	decl += to_name(func.self);
  	decl += "(";
  
  	if (!type.array.empty() && msl_options.force_native_arrays)
  	{
  		// Fake arrays returns by writing to an out array instead.
  		decl += "thread ";
  		decl += type_to_glsl(type);
  		decl += " (&spvReturnValue)";
  		decl += type_to_array_glsl(type);
  		if (!func.arguments.empty())
  			decl += ", ";
  	}
  
  	if (processing_entry_point)
  	{
  		if (msl_options.argument_buffers)
  			decl += entry_point_args_argument_buffer(!func.arguments.empty());
  		else
  			decl += entry_point_args_classic(!func.arguments.empty());
  
  		// If entry point function has variables that require early declaration,
  		// ensure they each have an empty initializer, creating one if needed.
  		// This is done at this late stage because the initialization expression
  		// is cleared after each compilation pass.
  		for (auto var_id : vars_needing_early_declaration)
  		{
  			auto &ed_var = get<SPIRVariable>(var_id);
  			ID &initializer = ed_var.initializer;
  			if (!initializer)
  				initializer = ir.increase_bound_by(1);
  
  			// Do not override proper initializers.
  			if (ir.ids[initializer].get_type() == TypeNone || ir.ids[initializer].get_type() == TypeExpression)
  				set<SPIRExpression>(ed_var.initializer, "{}", ed_var.basetype, true);
  		}
  	}
  
  	for (auto &arg : func.arguments)
  	{
  		uint32_t name_id = arg.id;
  
  		auto *var = maybe_get<SPIRVariable>(arg.id);
  		if (var)
  		{
  			// If we need to modify the name of the variable, make sure we modify the original variable.
  			// Our alias is just a shadow variable.
  			if (arg.alias_global_variable && var->basevariable)
  				name_id = var->basevariable;
  
  			var->parameter = &arg; // Hold a pointer to the parameter so we can invalidate the readonly field if needed.
  		}
  
  		add_local_variable_name(name_id);
  
  		decl += argument_decl(arg);
  
  		bool is_dynamic_img_sampler = has_extended_decoration(arg.id, SPIRVCrossDecorationDynamicImageSampler);
  
  		auto &arg_type = get<SPIRType>(arg.type);
  		if (arg_type.basetype == SPIRType::SampledImage && !is_dynamic_img_sampler)
  		{
  			// Manufacture automatic plane args for multiplanar texture
  			uint32_t planes = 1;
  			if (auto *constexpr_sampler = find_constexpr_sampler(name_id))
  				if (constexpr_sampler->ycbcr_conversion_enable)
  					planes = constexpr_sampler->planes;
  			for (uint32_t i = 1; i < planes; i++)
  				decl += join(", ", argument_decl(arg), plane_name_suffix, i);
  
  			// Manufacture automatic sampler arg for SampledImage texture
  			if (arg_type.image.dim != DimBuffer)
  				decl += join(", thread const ", sampler_type(arg_type, arg.id), " ", to_sampler_expression(arg.id));
  		}
  
  		// Manufacture automatic swizzle arg.
  		if (msl_options.swizzle_texture_samples && has_sampled_images && is_sampled_image_type(arg_type) &&
  		    !is_dynamic_img_sampler)
  		{
  			bool arg_is_array = !arg_type.array.empty();
  			decl += join(", constant uint", arg_is_array ? "* " : "& ", to_swizzle_expression(arg.id));
  		}
  
  		if (buffers_requiring_array_length.count(name_id))
  		{
  			bool arg_is_array = !arg_type.array.empty();
  			decl += join(", constant uint", arg_is_array ? "* " : "& ", to_buffer_size_expression(name_id));
  		}
  
  		if (&arg != &func.arguments.back())
  			decl += ", ";
  	}
  
  	decl += ")";
  	statement(decl);
  }
  
  static bool needs_chroma_reconstruction(const MSLConstexprSampler *constexpr_sampler)
  {
  	// For now, only multiplanar images need explicit reconstruction. GBGR and BGRG images
  	// use implicit reconstruction.
  	return constexpr_sampler && constexpr_sampler->ycbcr_conversion_enable && constexpr_sampler->planes > 1;
  }
  
  // Returns the texture sampling function string for the specified image and sampling characteristics.
  string CompilerMSL::to_function_name(const TextureFunctionNameArguments &args)
  {
  	VariableID img = args.base.img;
  	auto &imgtype = *args.base.imgtype;
  
  	const MSLConstexprSampler *constexpr_sampler = nullptr;
  	bool is_dynamic_img_sampler = false;
  	if (auto *var = maybe_get_backing_variable(img))
  	{
  		constexpr_sampler = find_constexpr_sampler(var->basevariable ? var->basevariable : VariableID(var->self));
  		is_dynamic_img_sampler = has_extended_decoration(var->self, SPIRVCrossDecorationDynamicImageSampler);
  	}
  
  	// Special-case gather. We have to alter the component being looked up
  	// in the swizzle case.
  	if (msl_options.swizzle_texture_samples && args.base.is_gather && !is_dynamic_img_sampler &&
  	    (!constexpr_sampler || !constexpr_sampler->ycbcr_conversion_enable))
  	{
  		add_spv_func_and_recompile(imgtype.image.depth ? SPVFuncImplGatherCompareSwizzle : SPVFuncImplGatherSwizzle);
  		return imgtype.image.depth ? "spvGatherCompareSwizzle" : "spvGatherSwizzle";
  	}
  
  	auto *combined = maybe_get<SPIRCombinedImageSampler>(img);
  
  	// Texture reference
  	string fname;
  	if (needs_chroma_reconstruction(constexpr_sampler) && !is_dynamic_img_sampler)
  	{
  		if (constexpr_sampler->planes != 2 && constexpr_sampler->planes != 3)
  			SPIRV_CROSS_THROW("Unhandled number of color image planes!");
  		// 444 images aren't downsampled, so we don't need to do linear filtering.
  		if (constexpr_sampler->resolution == MSL_FORMAT_RESOLUTION_444 ||
  		    constexpr_sampler->chroma_filter == MSL_SAMPLER_FILTER_NEAREST)
  		{
  			if (constexpr_sampler->planes == 2)
  				add_spv_func_and_recompile(SPVFuncImplChromaReconstructNearest2Plane);
  			else
  				add_spv_func_and_recompile(SPVFuncImplChromaReconstructNearest3Plane);
  			fname = "spvChromaReconstructNearest";
  		}
  		else // Linear with a downsampled format
  		{
  			fname = "spvChromaReconstructLinear";
  			switch (constexpr_sampler->resolution)
  			{
  			case MSL_FORMAT_RESOLUTION_444:
  				assert(false);
  				break; // not reached
  			case MSL_FORMAT_RESOLUTION_422:
  				switch (constexpr_sampler->x_chroma_offset)
  				{
  				case MSL_CHROMA_LOCATION_COSITED_EVEN:
  					if (constexpr_sampler->planes == 2)
  						add_spv_func_and_recompile(SPVFuncImplChromaReconstructLinear422CositedEven2Plane);
  					else
  						add_spv_func_and_recompile(SPVFuncImplChromaReconstructLinear422CositedEven3Plane);
  					fname += "422CositedEven";
  					break;
  				case MSL_CHROMA_LOCATION_MIDPOINT:
  					if (constexpr_sampler->planes == 2)
  						add_spv_func_and_recompile(SPVFuncImplChromaReconstructLinear422Midpoint2Plane);
  					else
  						add_spv_func_and_recompile(SPVFuncImplChromaReconstructLinear422Midpoint3Plane);
  					fname += "422Midpoint";
  					break;
  				default:
  					SPIRV_CROSS_THROW("Invalid chroma location.");
  				}
  				break;
  			case MSL_FORMAT_RESOLUTION_420:
  				fname += "420";
  				switch (constexpr_sampler->x_chroma_offset)
  				{
  				case MSL_CHROMA_LOCATION_COSITED_EVEN:
  					switch (constexpr_sampler->y_chroma_offset)
  					{
  					case MSL_CHROMA_LOCATION_COSITED_EVEN:
  						if (constexpr_sampler->planes == 2)
  							add_spv_func_and_recompile(
  							    SPVFuncImplChromaReconstructLinear420XCositedEvenYCositedEven2Plane);
  						else
  							add_spv_func_and_recompile(
  							    SPVFuncImplChromaReconstructLinear420XCositedEvenYCositedEven3Plane);
  						fname += "XCositedEvenYCositedEven";
  						break;
  					case MSL_CHROMA_LOCATION_MIDPOINT:
  						if (constexpr_sampler->planes == 2)
  							add_spv_func_and_recompile(
  							    SPVFuncImplChromaReconstructLinear420XCositedEvenYMidpoint2Plane);
  						else
  							add_spv_func_and_recompile(
  							    SPVFuncImplChromaReconstructLinear420XCositedEvenYMidpoint3Plane);
  						fname += "XCositedEvenYMidpoint";
  						break;
  					default:
  						SPIRV_CROSS_THROW("Invalid Y chroma location.");
  					}
  					break;
  				case MSL_CHROMA_LOCATION_MIDPOINT:
  					switch (constexpr_sampler->y_chroma_offset)
  					{
  					case MSL_CHROMA_LOCATION_COSITED_EVEN:
  						if (constexpr_sampler->planes == 2)
  							add_spv_func_and_recompile(
  							    SPVFuncImplChromaReconstructLinear420XMidpointYCositedEven2Plane);
  						else
  							add_spv_func_and_recompile(
  							    SPVFuncImplChromaReconstructLinear420XMidpointYCositedEven3Plane);
  						fname += "XMidpointYCositedEven";
  						break;
  					case MSL_CHROMA_LOCATION_MIDPOINT:
  						if (constexpr_sampler->planes == 2)
  							add_spv_func_and_recompile(SPVFuncImplChromaReconstructLinear420XMidpointYMidpoint2Plane);
  						else
  							add_spv_func_and_recompile(SPVFuncImplChromaReconstructLinear420XMidpointYMidpoint3Plane);
  						fname += "XMidpointYMidpoint";
  						break;
  					default:
  						SPIRV_CROSS_THROW("Invalid Y chroma location.");
  					}
  					break;
  				default:
  					SPIRV_CROSS_THROW("Invalid X chroma location.");
  				}
  				break;
  			default:
  				SPIRV_CROSS_THROW("Invalid format resolution.");
  			}
  		}
  	}
  	else
  	{
  		fname = to_expression(combined ? combined->image : img) + ".";
  
  		// Texture function and sampler
  		if (args.base.is_fetch)
  			fname += "read";
  		else if (args.base.is_gather)
  			fname += "gather";
  		else
  			fname += "sample";
  
  		if (args.has_dref)
  			fname += "_compare";
  	}
  
  	return fname;
  }
  
  string CompilerMSL::convert_to_f32(const string &expr, uint32_t components)
  {
  	SPIRType t;
  	t.basetype = SPIRType::Float;
  	t.vecsize = components;
  	t.columns = 1;
  	return join(type_to_glsl_constructor(t), "(", expr, ")");
  }
  
  static inline bool sampling_type_needs_f32_conversion(const SPIRType &type)
  {
  	// Double is not supported to begin with, but doesn't hurt to check for completion.
  	return type.basetype == SPIRType::Half || type.basetype == SPIRType::Double;
  }
  
  // Returns the function args for a texture sampling function for the specified image and sampling characteristics.
  string CompilerMSL::to_function_args(const TextureFunctionArguments &args, bool *p_forward)
  {
  	VariableID img = args.base.img;
  	auto &imgtype = *args.base.imgtype;
  	uint32_t lod = args.lod;
  	uint32_t grad_x = args.grad_x;
  	uint32_t grad_y = args.grad_y;
  	uint32_t bias = args.bias;
  
  	const MSLConstexprSampler *constexpr_sampler = nullptr;
  	bool is_dynamic_img_sampler = false;
  	if (auto *var = maybe_get_backing_variable(img))
  	{
  		constexpr_sampler = find_constexpr_sampler(var->basevariable ? var->basevariable : VariableID(var->self));
  		is_dynamic_img_sampler = has_extended_decoration(var->self, SPIRVCrossDecorationDynamicImageSampler);
  	}
  
  	string farg_str;
  	bool forward = true;
  
  	if (!is_dynamic_img_sampler)
  	{
  		// Texture reference (for some cases)
  		if (needs_chroma_reconstruction(constexpr_sampler))
  		{
  			// Multiplanar images need two or three textures.
  			farg_str += to_expression(img);
  			for (uint32_t i = 1; i < constexpr_sampler->planes; i++)
  				farg_str += join(", ", to_expression(img), plane_name_suffix, i);
  		}
  		else if ((!constexpr_sampler || !constexpr_sampler->ycbcr_conversion_enable) &&
  		         msl_options.swizzle_texture_samples && args.base.is_gather)
  		{
  			auto *combined = maybe_get<SPIRCombinedImageSampler>(img);
  			farg_str += to_expression(combined ? combined->image : img);
  		}
  
  		// Sampler reference
  		if (!args.base.is_fetch)
  		{
  			if (!farg_str.empty())
  				farg_str += ", ";
  			farg_str += to_sampler_expression(img);
  		}
  
  		if ((!constexpr_sampler || !constexpr_sampler->ycbcr_conversion_enable) &&
  		    msl_options.swizzle_texture_samples && args.base.is_gather)
  		{
  			// Add the swizzle constant from the swizzle buffer.
  			farg_str += ", " + to_swizzle_expression(img);
  			used_swizzle_buffer = true;
  		}
  
  		// Swizzled gather puts the component before the other args, to allow template
  		// deduction to work.
  		if (args.component && msl_options.swizzle_texture_samples)
  		{
  			forward = should_forward(args.component);
  			farg_str += ", " + to_component_argument(args.component);
  		}
  	}
  
  	// Texture coordinates
  	forward = forward && should_forward(args.coord);
  	auto coord_expr = to_enclosed_expression(args.coord);
  	auto &coord_type = expression_type(args.coord);
  	bool coord_is_fp = type_is_floating_point(coord_type);
  	bool is_cube_fetch = false;
  
  	string tex_coords = coord_expr;
  	uint32_t alt_coord_component = 0;
  
  	switch (imgtype.image.dim)
  	{
  
  	case Dim1D:
  		if (coord_type.vecsize > 1)
  			tex_coords = enclose_expression(tex_coords) + ".x";
  
  		if (args.base.is_fetch)
  			tex_coords = "uint(" + round_fp_tex_coords(tex_coords, coord_is_fp) + ")";
  		else if (sampling_type_needs_f32_conversion(coord_type))
  			tex_coords = convert_to_f32(tex_coords, 1);
  
  		if (msl_options.texture_1D_as_2D)
  		{
  			if (args.base.is_fetch)
  				tex_coords = "uint2(" + tex_coords + ", 0)";
  			else
  				tex_coords = "float2(" + tex_coords + ", 0.5)";
  		}
  
  		alt_coord_component = 1;
  		break;
  
  	case DimBuffer:
  		if (coord_type.vecsize > 1)
  			tex_coords = enclose_expression(tex_coords) + ".x";
  
  		if (msl_options.texture_buffer_native)
  		{
  			tex_coords = "uint(" + round_fp_tex_coords(tex_coords, coord_is_fp) + ")";
  		}
  		else
  		{
  			// Metal texel buffer textures are 2D, so convert 1D coord to 2D.
  			// Support for Metal 2.1's new texture_buffer type.
  			if (args.base.is_fetch)
  			{
  				if (msl_options.texel_buffer_texture_width > 0)
  				{
  					tex_coords = "spvTexelBufferCoord(" + round_fp_tex_coords(tex_coords, coord_is_fp) + ")";
  				}
  				else
  				{
  					tex_coords = "spvTexelBufferCoord(" + round_fp_tex_coords(tex_coords, coord_is_fp) + ", " +
  					             to_expression(img) + ")";
  				}
  			}
  		}
  
  		alt_coord_component = 1;
  		break;
  
  	case DimSubpassData:
  		// If we're using Metal's native frame-buffer fetch API for subpass inputs,
  		// this path will not be hit.
  		tex_coords = "uint2(gl_FragCoord.xy)";
  		alt_coord_component = 2;
  		break;
  
  	case Dim2D:
  		if (coord_type.vecsize > 2)
  			tex_coords = enclose_expression(tex_coords) + ".xy";
  
  		if (args.base.is_fetch)
  			tex_coords = "uint2(" + round_fp_tex_coords(tex_coords, coord_is_fp) + ")";
  		else if (sampling_type_needs_f32_conversion(coord_type))
  			tex_coords = convert_to_f32(tex_coords, 2);
  
  		alt_coord_component = 2;
  		break;
  
  	case Dim3D:
  		if (coord_type.vecsize > 3)
  			tex_coords = enclose_expression(tex_coords) + ".xyz";
  
  		if (args.base.is_fetch)
  			tex_coords = "uint3(" + round_fp_tex_coords(tex_coords, coord_is_fp) + ")";
  		else if (sampling_type_needs_f32_conversion(coord_type))
  			tex_coords = convert_to_f32(tex_coords, 3);
  
  		alt_coord_component = 3;
  		break;
  
  	case DimCube:
  		if (args.base.is_fetch)
  		{
  			is_cube_fetch = true;
  			tex_coords += ".xy";
  			tex_coords = "uint2(" + round_fp_tex_coords(tex_coords, coord_is_fp) + ")";
  		}
  		else
  		{
  			if (coord_type.vecsize > 3)
  				tex_coords = enclose_expression(tex_coords) + ".xyz";
  		}
  
  		if (sampling_type_needs_f32_conversion(coord_type))
  			tex_coords = convert_to_f32(tex_coords, 3);
  
  		alt_coord_component = 3;
  		break;
  
  	default:
  		break;
  	}
  
  	if (args.base.is_fetch && (args.offset || args.coffset))
  	{
  		uint32_t offset_expr = args.offset ? args.offset : args.coffset;
  		// Fetch offsets must be applied directly to the coordinate.
  		forward = forward && should_forward(offset_expr);
  		auto &type = expression_type(offset_expr);
  		if (imgtype.image.dim == Dim1D && msl_options.texture_1D_as_2D)
  		{
  			if (type.basetype != SPIRType::UInt)
  				tex_coords += join(" + uint2(", bitcast_expression(SPIRType::UInt, offset_expr), ", 0)");
  			else
  				tex_coords += join(" + uint2(", to_enclosed_expression(offset_expr), ", 0)");
  		}
  		else
  		{
  			if (type.basetype != SPIRType::UInt)
  				tex_coords += " + " + bitcast_expression(SPIRType::UInt, offset_expr);
  			else
  				tex_coords += " + " + to_enclosed_expression(offset_expr);
  		}
  	}
  
  	// If projection, use alt coord as divisor
  	if (args.base.is_proj)
  	{
  		if (sampling_type_needs_f32_conversion(coord_type))
  			tex_coords += " / " + convert_to_f32(to_extract_component_expression(args.coord, alt_coord_component), 1);
  		else
  			tex_coords += " / " + to_extract_component_expression(args.coord, alt_coord_component);
  	}
  
  	if (!farg_str.empty())
  		farg_str += ", ";
  
  	if (imgtype.image.dim == DimCube && imgtype.image.arrayed && msl_options.emulate_cube_array)
  	{
  		farg_str += "spvCubemapTo2DArrayFace(" + tex_coords + ").xy";
  
  		if (is_cube_fetch)
  			farg_str += ", uint(" + to_extract_component_expression(args.coord, 2) + ")";
  		else
  			farg_str +=
  			    ", uint(spvCubemapTo2DArrayFace(" + tex_coords + ").z) + (uint(" +
  			    round_fp_tex_coords(to_extract_component_expression(args.coord, alt_coord_component), coord_is_fp) +
  			    ") * 6u)";
  
  		add_spv_func_and_recompile(SPVFuncImplCubemapTo2DArrayFace);
  	}
  	else
  	{
  		farg_str += tex_coords;
  
  		// If fetch from cube, add face explicitly
  		if (is_cube_fetch)
  		{
  			// Special case for cube arrays, face and layer are packed in one dimension.
  			if (imgtype.image.arrayed)
  				farg_str += ", uint(" + to_extract_component_expression(args.coord, 2) + ") % 6u";
  			else
  				farg_str +=
  				    ", uint(" + round_fp_tex_coords(to_extract_component_expression(args.coord, 2), coord_is_fp) + ")";
  		}
  
  		// If array, use alt coord
  		if (imgtype.image.arrayed)
  		{
  			// Special case for cube arrays, face and layer are packed in one dimension.
  			if (imgtype.image.dim == DimCube && args.base.is_fetch)
  			{
  				farg_str += ", uint(" + to_extract_component_expression(args.coord, 2) + ") / 6u";
  			}
  			else
  			{
  				farg_str +=
  				    ", uint(" +
  				    round_fp_tex_coords(to_extract_component_expression(args.coord, alt_coord_component), coord_is_fp) +
  				    ")";
  				if (imgtype.image.dim == DimSubpassData)
  				{
  					if (msl_options.multiview)
  						farg_str += " + gl_ViewIndex";
  					else if (msl_options.arrayed_subpass_input)
  						farg_str += " + gl_Layer";
  				}
  			}
  		}
  		else if (imgtype.image.dim == DimSubpassData)
  		{
  			if (msl_options.multiview)
  				farg_str += ", gl_ViewIndex";
  			else if (msl_options.arrayed_subpass_input)
  				farg_str += ", gl_Layer";
  		}
  	}
  
  	// Depth compare reference value
  	if (args.dref)
  	{
  		forward = forward && should_forward(args.dref);
  		farg_str += ", ";
  
  		auto &dref_type = expression_type(args.dref);
  
  		string dref_expr;
  		if (args.base.is_proj)
  			dref_expr = join(to_enclosed_expression(args.dref), " / ",
  			                 to_extract_component_expression(args.coord, alt_coord_component));
  		else
  			dref_expr = to_expression(args.dref);
  
  		if (sampling_type_needs_f32_conversion(dref_type))
  			dref_expr = convert_to_f32(dref_expr, 1);
  
  		farg_str += dref_expr;
  
  		if (msl_options.is_macos() && (grad_x || grad_y))
  		{
  			// For sample compare, MSL does not support gradient2d for all targets (only iOS apparently according to docs).
  			// However, the most common case here is to have a constant gradient of 0, as that is the only way to express
  			// LOD == 0 in GLSL with sampler2DArrayShadow (cascaded shadow mapping).
  			// We will detect a compile-time constant 0 value for gradient and promote that to level(0) on MSL.
  			bool constant_zero_x = !grad_x || expression_is_constant_null(grad_x);
  			bool constant_zero_y = !grad_y || expression_is_constant_null(grad_y);
  			if (constant_zero_x && constant_zero_y)
  			{
  				lod = 0;
  				grad_x = 0;
  				grad_y = 0;
  				farg_str += ", level(0)";
  			}
  			else if (!msl_options.supports_msl_version(2, 3))
  			{
  				SPIRV_CROSS_THROW("Using non-constant 0.0 gradient() qualifier for sample_compare. This is not "
  				                  "supported on macOS prior to MSL 2.3.");
  			}
  		}
  
  		if (msl_options.is_macos() && bias)
  		{
  			// Bias is not supported either on macOS with sample_compare.
  			// Verify it is compile-time zero, and drop the argument.
  			if (expression_is_constant_null(bias))
  			{
  				bias = 0;
  			}
  			else if (!msl_options.supports_msl_version(2, 3))
  			{
  				SPIRV_CROSS_THROW("Using non-constant 0.0 bias() qualifier for sample_compare. This is not supported "
  				                  "on macOS prior to MSL 2.3.");
  			}
  		}
  	}
  
  	// LOD Options
  	// Metal does not support LOD for 1D textures.
  	if (bias && (imgtype.image.dim != Dim1D || msl_options.texture_1D_as_2D))
  	{
  		forward = forward && should_forward(bias);
  		farg_str += ", bias(" + to_expression(bias) + ")";
  	}
  
  	// Metal does not support LOD for 1D textures.
  	if (lod && (imgtype.image.dim != Dim1D || msl_options.texture_1D_as_2D))
  	{
  		forward = forward && should_forward(lod);
  		if (args.base.is_fetch)
  		{
  			farg_str += ", " + to_expression(lod);
  		}
  		else
  		{
  			farg_str += ", level(" + to_expression(lod) + ")";
  		}
  	}
  	else if (args.base.is_fetch && !lod && (imgtype.image.dim != Dim1D || msl_options.texture_1D_as_2D) &&
  	         imgtype.image.dim != DimBuffer && !imgtype.image.ms && imgtype.image.sampled != 2)
  	{
  		// Lod argument is optional in OpImageFetch, but we require a LOD value, pick 0 as the default.
  		// Check for sampled type as well, because is_fetch is also used for OpImageRead in MSL.
  		farg_str += ", 0";
  	}
  
  	// Metal does not support LOD for 1D textures.
  	if ((grad_x || grad_y) && (imgtype.image.dim != Dim1D || msl_options.texture_1D_as_2D))
  	{
  		forward = forward && should_forward(grad_x);
  		forward = forward && should_forward(grad_y);
  		string grad_opt;
  		switch (imgtype.image.dim)
  		{
  		case Dim1D:
  		case Dim2D:
  			grad_opt = "2d";
  			break;
  		case Dim3D:
  			grad_opt = "3d";
  			break;
  		case DimCube:
  			if (imgtype.image.arrayed && msl_options.emulate_cube_array)
  				grad_opt = "2d";
  			else
  				grad_opt = "cube";
  			break;
  		default:
  			grad_opt = "unsupported_gradient_dimension";
  			break;
  		}
  		farg_str += ", gradient" + grad_opt + "(" + to_expression(grad_x) + ", " + to_expression(grad_y) + ")";
  	}
  
  	if (args.min_lod)
  	{
  		if (!msl_options.supports_msl_version(2, 2))
  			SPIRV_CROSS_THROW("min_lod_clamp() is only supported in MSL 2.2+ and up.");
  
  		forward = forward && should_forward(args.min_lod);
  		farg_str += ", min_lod_clamp(" + to_expression(args.min_lod) + ")";
  	}
  
  	// Add offsets
  	string offset_expr;
  	const SPIRType *offset_type = nullptr;
  	if (args.coffset && !args.base.is_fetch)
  	{
  		forward = forward && should_forward(args.coffset);
  		offset_expr = to_expression(args.coffset);
  		offset_type = &expression_type(args.coffset);
  	}
  	else if (args.offset && !args.base.is_fetch)
  	{
  		forward = forward && should_forward(args.offset);
  		offset_expr = to_expression(args.offset);
  		offset_type = &expression_type(args.offset);
  	}
  
  	if (!offset_expr.empty())
  	{
  		switch (imgtype.image.dim)
  		{
  		case Dim1D:
  			if (!msl_options.texture_1D_as_2D)
  				break;
  			if (offset_type->vecsize > 1)
  				offset_expr = enclose_expression(offset_expr) + ".x";
  
  			farg_str += join(", int2(", offset_expr, ", 0)");
  			break;
  
  		case Dim2D:
  			if (offset_type->vecsize > 2)
  				offset_expr = enclose_expression(offset_expr) + ".xy";
  
  			farg_str += ", " + offset_expr;
  			break;
  
  		case Dim3D:
  			if (offset_type->vecsize > 3)
  				offset_expr = enclose_expression(offset_expr) + ".xyz";
  
  			farg_str += ", " + offset_expr;
  			break;
  
  		default:
  			break;
  		}
  	}
  
  	if (args.component)
  	{
  		// If 2D has gather component, ensure it also has an offset arg
  		if (imgtype.image.dim == Dim2D && offset_expr.empty())
  			farg_str += ", int2(0)";
  
  		if (!msl_options.swizzle_texture_samples || is_dynamic_img_sampler)
  		{
  			forward = forward && should_forward(args.component);
  
  			uint32_t image_var = 0;
  			if (const auto *combined = maybe_get<SPIRCombinedImageSampler>(img))
  			{
  				if (const auto *img_var = maybe_get_backing_variable(combined->image))
  					image_var = img_var->self;
  			}
  			else if (const auto *var = maybe_get_backing_variable(img))
  			{
  				image_var = var->self;
  			}
  
  			if (image_var == 0 || !image_is_comparison(expression_type(image_var), image_var))
  				farg_str += ", " + to_component_argument(args.component);
  		}
  	}
  
  	if (args.sample)
  	{
  		forward = forward && should_forward(args.sample);
  		farg_str += ", ";
  		farg_str += to_expression(args.sample);
  	}
  
  	*p_forward = forward;
  
  	return farg_str;
  }
  
  // If the texture coordinates are floating point, invokes MSL round() function to round them.
  string CompilerMSL::round_fp_tex_coords(string tex_coords, bool coord_is_fp)
  {
  	return coord_is_fp ? ("round(" + tex_coords + ")") : tex_coords;
  }
  
  // Returns a string to use in an image sampling function argument.
  // The ID must be a scalar constant.
  string CompilerMSL::to_component_argument(uint32_t id)
  {
  	uint32_t component_index = evaluate_constant_u32(id);
  	switch (component_index)
  	{
  	case 0:
  		return "component::x";
  	case 1:
  		return "component::y";
  	case 2:
  		return "component::z";
  	case 3:
  		return "component::w";
  
  	default:
  		SPIRV_CROSS_THROW("The value (" + to_string(component_index) + ") of OpConstant ID " + to_string(id) +
  		                  " is not a valid Component index, which must be one of 0, 1, 2, or 3.");
  	}
  }
  
  // Establish sampled image as expression object and assign the sampler to it.
  void CompilerMSL::emit_sampled_image_op(uint32_t result_type, uint32_t result_id, uint32_t image_id, uint32_t samp_id)
  {
  	set<SPIRCombinedImageSampler>(result_id, result_type, image_id, samp_id);
  }
  
  string CompilerMSL::to_texture_op(const Instruction &i, bool sparse, bool *forward,
                                    SmallVector<uint32_t> &inherited_expressions)
  {
  	auto *ops = stream(i);
  	uint32_t result_type_id = ops[0];
  	uint32_t img = ops[2];
  	auto &result_type = get<SPIRType>(result_type_id);
  	auto op = static_cast<Op>(i.op);
  	bool is_gather = (op == OpImageGather || op == OpImageDrefGather);
  
  	// Bypass pointers because we need the real image struct
  	auto &type = expression_type(img);
  	auto &imgtype = get<SPIRType>(type.self);
  
  	const MSLConstexprSampler *constexpr_sampler = nullptr;
  	bool is_dynamic_img_sampler = false;
  	if (auto *var = maybe_get_backing_variable(img))
  	{
  		constexpr_sampler = find_constexpr_sampler(var->basevariable ? var->basevariable : VariableID(var->self));
  		is_dynamic_img_sampler = has_extended_decoration(var->self, SPIRVCrossDecorationDynamicImageSampler);
  	}
  
  	string expr;
  	if (constexpr_sampler && constexpr_sampler->ycbcr_conversion_enable && !is_dynamic_img_sampler)
  	{
  		// If this needs sampler Y'CbCr conversion, we need to do some additional
  		// processing.
  		switch (constexpr_sampler->ycbcr_model)
  		{
  		case MSL_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY:
  		case MSL_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY:
  			// Default
  			break;
  		case MSL_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_BT_709:
  			add_spv_func_and_recompile(SPVFuncImplConvertYCbCrBT709);
  			expr += "spvConvertYCbCrBT709(";
  			break;
  		case MSL_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_BT_601:
  			add_spv_func_and_recompile(SPVFuncImplConvertYCbCrBT601);
  			expr += "spvConvertYCbCrBT601(";
  			break;
  		case MSL_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_BT_2020:
  			add_spv_func_and_recompile(SPVFuncImplConvertYCbCrBT2020);
  			expr += "spvConvertYCbCrBT2020(";
  			break;
  		default:
  			SPIRV_CROSS_THROW("Invalid Y'CbCr model conversion.");
  		}
  
  		if (constexpr_sampler->ycbcr_model != MSL_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY)
  		{
  			switch (constexpr_sampler->ycbcr_range)
  			{
  			case MSL_SAMPLER_YCBCR_RANGE_ITU_FULL:
  				add_spv_func_and_recompile(SPVFuncImplExpandITUFullRange);
  				expr += "spvExpandITUFullRange(";
  				break;
  			case MSL_SAMPLER_YCBCR_RANGE_ITU_NARROW:
  				add_spv_func_and_recompile(SPVFuncImplExpandITUNarrowRange);
  				expr += "spvExpandITUNarrowRange(";
  				break;
  			default:
  				SPIRV_CROSS_THROW("Invalid Y'CbCr range.");
  			}
  		}
  	}
  	else if (msl_options.swizzle_texture_samples && !is_gather && is_sampled_image_type(imgtype) &&
  	         !is_dynamic_img_sampler)
  	{
  		add_spv_func_and_recompile(SPVFuncImplTextureSwizzle);
  		expr += "spvTextureSwizzle(";
  	}
  
  	string inner_expr = CompilerGLSL::to_texture_op(i, sparse, forward, inherited_expressions);
  
  	if (constexpr_sampler && constexpr_sampler->ycbcr_conversion_enable && !is_dynamic_img_sampler)
  	{
  		if (!constexpr_sampler->swizzle_is_identity())
  		{
  			static const char swizzle_names[] = "rgba";
  			if (!constexpr_sampler->swizzle_has_one_or_zero())
  			{
  				// If we can, do it inline.
  				expr += inner_expr + ".";
  				for (uint32_t c = 0; c < 4; c++)
  				{
  					switch (constexpr_sampler->swizzle[c])
  					{
  					case MSL_COMPONENT_SWIZZLE_IDENTITY:
  						expr += swizzle_names[c];
  						break;
  					case MSL_COMPONENT_SWIZZLE_R:
  					case MSL_COMPONENT_SWIZZLE_G:
  					case MSL_COMPONENT_SWIZZLE_B:
  					case MSL_COMPONENT_SWIZZLE_A:
  						expr += swizzle_names[constexpr_sampler->swizzle[c] - MSL_COMPONENT_SWIZZLE_R];
  						break;
  					default:
  						SPIRV_CROSS_THROW("Invalid component swizzle.");
  					}
  				}
  			}
  			else
  			{
  				// Otherwise, we need to emit a temporary and swizzle that.
  				uint32_t temp_id = ir.increase_bound_by(1);
  				emit_op(result_type_id, temp_id, inner_expr, false);
  				for (auto &inherit : inherited_expressions)
  					inherit_expression_dependencies(temp_id, inherit);
  				inherited_expressions.clear();
  				inherited_expressions.push_back(temp_id);
  
  				switch (op)
  				{
  				case OpImageSampleDrefImplicitLod:
  				case OpImageSampleImplicitLod:
  				case OpImageSampleProjImplicitLod:
  				case OpImageSampleProjDrefImplicitLod:
  					register_control_dependent_expression(temp_id);
  					break;
  
  				default:
  					break;
  				}
  				expr += type_to_glsl(result_type) + "(";
  				for (uint32_t c = 0; c < 4; c++)
  				{
  					switch (constexpr_sampler->swizzle[c])
  					{
  					case MSL_COMPONENT_SWIZZLE_IDENTITY:
  						expr += to_expression(temp_id) + "." + swizzle_names[c];
  						break;
  					case MSL_COMPONENT_SWIZZLE_ZERO:
  						expr += "0";
  						break;
  					case MSL_COMPONENT_SWIZZLE_ONE:
  						expr += "1";
  						break;
  					case MSL_COMPONENT_SWIZZLE_R:
  					case MSL_COMPONENT_SWIZZLE_G:
  					case MSL_COMPONENT_SWIZZLE_B:
  					case MSL_COMPONENT_SWIZZLE_A:
  						expr += to_expression(temp_id) + "." +
  						        swizzle_names[constexpr_sampler->swizzle[c] - MSL_COMPONENT_SWIZZLE_R];
  						break;
  					default:
  						SPIRV_CROSS_THROW("Invalid component swizzle.");
  					}
  					if (c < 3)
  						expr += ", ";
  				}
  				expr += ")";
  			}
  		}
  		else
  			expr += inner_expr;
  		if (constexpr_sampler->ycbcr_model != MSL_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY)
  		{
  			expr += join(", ", constexpr_sampler->bpc, ")");
  			if (constexpr_sampler->ycbcr_model != MSL_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY)
  				expr += ")";
  		}
  	}
  	else
  	{
  		expr += inner_expr;
  		if (msl_options.swizzle_texture_samples && !is_gather && is_sampled_image_type(imgtype) &&
  		    !is_dynamic_img_sampler)
  		{
  			// Add the swizzle constant from the swizzle buffer.
  			expr += ", " + to_swizzle_expression(img) + ")";
  			used_swizzle_buffer = true;
  		}
  	}
  
  	return expr;
  }
  
  static string create_swizzle(MSLComponentSwizzle swizzle)
  {
  	switch (swizzle)
  	{
  	case MSL_COMPONENT_SWIZZLE_IDENTITY:
  		return "spvSwizzle::none";
  	case MSL_COMPONENT_SWIZZLE_ZERO:
  		return "spvSwizzle::zero";
  	case MSL_COMPONENT_SWIZZLE_ONE:
  		return "spvSwizzle::one";
  	case MSL_COMPONENT_SWIZZLE_R:
  		return "spvSwizzle::red";
  	case MSL_COMPONENT_SWIZZLE_G:
  		return "spvSwizzle::green";
  	case MSL_COMPONENT_SWIZZLE_B:
  		return "spvSwizzle::blue";
  	case MSL_COMPONENT_SWIZZLE_A:
  		return "spvSwizzle::alpha";
  	default:
  		SPIRV_CROSS_THROW("Invalid component swizzle.");
  	}
  }
  
  // Returns a string representation of the ID, usable as a function arg.
  // Manufacture automatic sampler arg for SampledImage texture.
  string CompilerMSL::to_func_call_arg(const SPIRFunction::Parameter &arg, uint32_t id)
  {
  	string arg_str;
  
  	auto &type = expression_type(id);
  	bool is_dynamic_img_sampler = has_extended_decoration(arg.id, SPIRVCrossDecorationDynamicImageSampler);
  	// If the argument *itself* is a "dynamic" combined-image sampler, then we can just pass that around.
  	bool arg_is_dynamic_img_sampler = has_extended_decoration(id, SPIRVCrossDecorationDynamicImageSampler);
  	if (is_dynamic_img_sampler && !arg_is_dynamic_img_sampler)
  		arg_str = join("spvDynamicImageSampler<", type_to_glsl(get<SPIRType>(type.image.type)), ">(");
  
  	auto *c = maybe_get<SPIRConstant>(id);
  	if (msl_options.force_native_arrays && c && !get<SPIRType>(c->constant_type).array.empty())
  	{
  		// If we are passing a constant array directly to a function for some reason,
  		// the callee will expect an argument in thread const address space
  		// (since we can only bind to arrays with references in MSL).
  		// To resolve this, we must emit a copy in this address space.
  		// This kind of code gen should be rare enough that performance is not a real concern.
  		// Inline the SPIR-V to avoid this kind of suboptimal codegen.
  		//
  		// We risk calling this inside a continue block (invalid code),
  		// so just create a thread local copy in the current function.
  		arg_str = join("_", id, "_array_copy");
  		auto &constants = current_function->constant_arrays_needed_on_stack;
  		auto itr = find(begin(constants), end(constants), ID(id));
  		if (itr == end(constants))
  		{
  			force_recompile();
  			constants.push_back(id);
  		}
  	}
  	else
  		arg_str += CompilerGLSL::to_func_call_arg(arg, id);
  
  	// Need to check the base variable in case we need to apply a qualified alias.
  	uint32_t var_id = 0;
  	auto *var = maybe_get<SPIRVariable>(id);
  	if (var)
  		var_id = var->basevariable;
  
  	if (!arg_is_dynamic_img_sampler)
  	{
  		auto *constexpr_sampler = find_constexpr_sampler(var_id ? var_id : id);
  		if (type.basetype == SPIRType::SampledImage)
  		{
  			// Manufacture automatic plane args for multiplanar texture
  			uint32_t planes = 1;
  			if (constexpr_sampler && constexpr_sampler->ycbcr_conversion_enable)
  			{
  				planes = constexpr_sampler->planes;
  				// If this parameter isn't aliasing a global, then we need to use
  				// the special "dynamic image-sampler" class to pass it--and we need
  				// to use it for *every* non-alias parameter, in case a combined
  				// image-sampler with a Y'CbCr conversion is passed. Hopefully, this
  				// pathological case is so rare that it should never be hit in practice.
  				if (!arg.alias_global_variable)
  					add_spv_func_and_recompile(SPVFuncImplDynamicImageSampler);
  			}
  			for (uint32_t i = 1; i < planes; i++)
  				arg_str += join(", ", CompilerGLSL::to_func_call_arg(arg, id), plane_name_suffix, i);
  			// Manufacture automatic sampler arg if the arg is a SampledImage texture.
  			if (type.image.dim != DimBuffer)
  				arg_str += ", " + to_sampler_expression(var_id ? var_id : id);
  
  			// Add sampler Y'CbCr conversion info if we have it
  			if (is_dynamic_img_sampler && constexpr_sampler && constexpr_sampler->ycbcr_conversion_enable)
  			{
  				SmallVector<string> samp_args;
  
  				switch (constexpr_sampler->resolution)
  				{
  				case MSL_FORMAT_RESOLUTION_444:
  					// Default
  					break;
  				case MSL_FORMAT_RESOLUTION_422:
  					samp_args.push_back("spvFormatResolution::_422");
  					break;
  				case MSL_FORMAT_RESOLUTION_420:
  					samp_args.push_back("spvFormatResolution::_420");
  					break;
  				default:
  					SPIRV_CROSS_THROW("Invalid format resolution.");
  				}
  
  				if (constexpr_sampler->chroma_filter != MSL_SAMPLER_FILTER_NEAREST)
  					samp_args.push_back("spvChromaFilter::linear");
  
  				if (constexpr_sampler->x_chroma_offset != MSL_CHROMA_LOCATION_COSITED_EVEN)
  					samp_args.push_back("spvXChromaLocation::midpoint");
  				if (constexpr_sampler->y_chroma_offset != MSL_CHROMA_LOCATION_COSITED_EVEN)
  					samp_args.push_back("spvYChromaLocation::midpoint");
  				switch (constexpr_sampler->ycbcr_model)
  				{
  				case MSL_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY:
  					// Default
  					break;
  				case MSL_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY:
  					samp_args.push_back("spvYCbCrModelConversion::ycbcr_identity");
  					break;
  				case MSL_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_BT_709:
  					samp_args.push_back("spvYCbCrModelConversion::ycbcr_bt_709");
  					break;
  				case MSL_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_BT_601:
  					samp_args.push_back("spvYCbCrModelConversion::ycbcr_bt_601");
  					break;
  				case MSL_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_BT_2020:
  					samp_args.push_back("spvYCbCrModelConversion::ycbcr_bt_2020");
  					break;
  				default:
  					SPIRV_CROSS_THROW("Invalid Y'CbCr model conversion.");
  				}
  				if (constexpr_sampler->ycbcr_range != MSL_SAMPLER_YCBCR_RANGE_ITU_FULL)
  					samp_args.push_back("spvYCbCrRange::itu_narrow");
  				samp_args.push_back(join("spvComponentBits(", constexpr_sampler->bpc, ")"));
  				arg_str += join(", spvYCbCrSampler(", merge(samp_args), ")");
  			}
  		}
  
  		if (is_dynamic_img_sampler && constexpr_sampler && constexpr_sampler->ycbcr_conversion_enable)
  			arg_str += join(", (uint(", create_swizzle(constexpr_sampler->swizzle[3]), ") << 24) | (uint(",
  			                create_swizzle(constexpr_sampler->swizzle[2]), ") << 16) | (uint(",
  			                create_swizzle(constexpr_sampler->swizzle[1]), ") << 8) | uint(",
  			                create_swizzle(constexpr_sampler->swizzle[0]), ")");
  		else if (msl_options.swizzle_texture_samples && has_sampled_images && is_sampled_image_type(type))
  			arg_str += ", " + to_swizzle_expression(var_id ? var_id : id);
  
  		if (buffers_requiring_array_length.count(var_id))
  			arg_str += ", " + to_buffer_size_expression(var_id ? var_id : id);
  
  		if (is_dynamic_img_sampler)
  			arg_str += ")";
  	}
  
  	// Emulate texture2D atomic operations
  	auto *backing_var = maybe_get_backing_variable(var_id);
  	if (backing_var && atomic_image_vars.count(backing_var->self))
  	{
  		arg_str += ", " + to_expression(var_id) + "_atomic";
  	}
  
  	return arg_str;
  }
  
  // If the ID represents a sampled image that has been assigned a sampler already,
  // generate an expression for the sampler, otherwise generate a fake sampler name
  // by appending a suffix to the expression constructed from the ID.
  string CompilerMSL::to_sampler_expression(uint32_t id)
  {
  	auto *combined = maybe_get<SPIRCombinedImageSampler>(id);
  	auto expr = to_expression(combined ? combined->image : VariableID(id));
  	auto index = expr.find_first_of('[');
  
  	uint32_t samp_id = 0;
  	if (combined)
  		samp_id = combined->sampler;
  
  	if (index == string::npos)
  		return samp_id ? to_expression(samp_id) : expr + sampler_name_suffix;
  	else
  	{
  		auto image_expr = expr.substr(0, index);
  		auto array_expr = expr.substr(index);
  		return samp_id ? to_expression(samp_id) : (image_expr + sampler_name_suffix + array_expr);
  	}
  }
  
  string CompilerMSL::to_swizzle_expression(uint32_t id)
  {
  	auto *combined = maybe_get<SPIRCombinedImageSampler>(id);
  
  	auto expr = to_expression(combined ? combined->image : VariableID(id));
  	auto index = expr.find_first_of('[');
  
  	// If an image is part of an argument buffer translate this to a legal identifier.
  	string::size_type period = 0;
  	while ((period = expr.find_first_of('.', period)) != string::npos && period < index)
  		expr[period] = '_';
  
  	if (index == string::npos)
  		return expr + swizzle_name_suffix;
  	else
  	{
  		auto image_expr = expr.substr(0, index);
  		auto array_expr = expr.substr(index);
  		return image_expr + swizzle_name_suffix + array_expr;
  	}
  }
  
  string CompilerMSL::to_buffer_size_expression(uint32_t id)
  {
  	auto expr = to_expression(id);
  	auto index = expr.find_first_of('[');
  
  	// This is quite crude, but we need to translate the reference name (*spvDescriptorSetN.name) to
  	// the pointer expression spvDescriptorSetN.name to make a reasonable expression here.
  	// This only happens if we have argument buffers and we are using OpArrayLength on a lone SSBO in that set.
  	if (expr.size() >= 3 && expr[0] == '(' && expr[1] == '*')
  		expr = address_of_expression(expr);
  
  	// If a buffer is part of an argument buffer translate this to a legal identifier.
  	for (auto &c : expr)
  		if (c == '.')
  			c = '_';
  
  	if (index == string::npos)
  		return expr + buffer_size_name_suffix;
  	else
  	{
  		auto buffer_expr = expr.substr(0, index);
  		auto array_expr = expr.substr(index);
  		return buffer_expr + buffer_size_name_suffix + array_expr;
  	}
  }
  
  // Checks whether the type is a Block all of whose members have DecorationPatch.
  bool CompilerMSL::is_patch_block(const SPIRType &type)
  {
  	if (!has_decoration(type.self, DecorationBlock))
  		return false;
  
  	for (uint32_t i = 0; i < type.member_types.size(); i++)
  	{
  		if (!has_member_decoration(type.self, i, DecorationPatch))
  			return false;
  	}
  
  	return true;
  }
  
  // Checks whether the ID is a row_major matrix that requires conversion before use
  bool CompilerMSL::is_non_native_row_major_matrix(uint32_t id)
  {
  	auto *e = maybe_get<SPIRExpression>(id);
  	if (e)
  		return e->need_transpose;
  	else
  		return has_decoration(id, DecorationRowMajor);
  }
  
  // Checks whether the member is a row_major matrix that requires conversion before use
  bool CompilerMSL::member_is_non_native_row_major_matrix(const SPIRType &type, uint32_t index)
  {
  	return has_member_decoration(type.self, index, DecorationRowMajor);
  }
  
  string CompilerMSL::convert_row_major_matrix(string exp_str, const SPIRType &exp_type, uint32_t physical_type_id,
                                               bool is_packed)
  {
  	if (!is_matrix(exp_type))
  	{
  		return CompilerGLSL::convert_row_major_matrix(move(exp_str), exp_type, physical_type_id, is_packed);
  	}
  	else
  	{
  		strip_enclosed_expression(exp_str);
  		if (physical_type_id != 0 || is_packed)
  			exp_str = unpack_expression_type(exp_str, exp_type, physical_type_id, is_packed, true);
  		return join("transpose(", exp_str, ")");
  	}
  }
  
  // Called automatically at the end of the entry point function
  void CompilerMSL::emit_fixup()
  {
  	if (is_vertex_like_shader() && stage_out_var_id && !qual_pos_var_name.empty() && !capture_output_to_buffer)
  	{
  		if (options.vertex.fixup_clipspace)
  			statement(qual_pos_var_name, ".z = (", qual_pos_var_name, ".z + ", qual_pos_var_name,
  			          ".w) * 0.5;       // Adjust clip-space for Metal");
  
  		if (options.vertex.flip_vert_y)
  			statement(qual_pos_var_name, ".y = -(", qual_pos_var_name, ".y);", "    // Invert Y-axis for Metal");
  	}
  }
  
  // Return a string defining a structure member, with padding and packing.
  string CompilerMSL::to_struct_member(const SPIRType &type, uint32_t member_type_id, uint32_t index,
                                       const string &qualifier)
  {
  	if (member_is_remapped_physical_type(type, index))
  		member_type_id = get_extended_member_decoration(type.self, index, SPIRVCrossDecorationPhysicalTypeID);
  	auto &physical_type = get<SPIRType>(member_type_id);
  
  	// If this member is packed, mark it as so.
  	string pack_pfx;
  
  	// Allow Metal to use the array<T> template to make arrays a value type
  	uint32_t orig_id = 0;
  	if (has_extended_member_decoration(type.self, index, SPIRVCrossDecorationInterfaceOrigID))
  		orig_id = get_extended_member_decoration(type.self, index, SPIRVCrossDecorationInterfaceOrigID);
  
  	bool row_major = false;
  	if (is_matrix(physical_type))
  		row_major = has_member_decoration(type.self, index, DecorationRowMajor);
  
  	SPIRType row_major_physical_type;
  	const SPIRType *declared_type = &physical_type;
  
  	// If a struct is being declared with physical layout,
  	// do not use array<T> wrappers.
  	// This avoids a lot of complicated cases with packed vectors and matrices,
  	// and generally we cannot copy full arrays in and out of buffers into Function
  	// address space.
  	// Array of resources should also be declared as builtin arrays.
  	if (has_member_decoration(type.self, index, DecorationOffset))
  		is_using_builtin_array = true;
  	else if (has_extended_member_decoration(type.self, index, SPIRVCrossDecorationResourceIndexPrimary))
  		is_using_builtin_array = true;
  
  	if (member_is_packed_physical_type(type, index))
  	{
  		// If we're packing a matrix, output an appropriate typedef
  		if (physical_type.basetype == SPIRType::Struct)
  		{
  			SPIRV_CROSS_THROW("Cannot emit a packed struct currently.");
  		}
  		else if (is_matrix(physical_type))
  		{
  			uint32_t rows = physical_type.vecsize;
  			uint32_t cols = physical_type.columns;
  			pack_pfx = "packed_";
  			if (row_major)
  			{
  				// These are stored transposed.
  				rows = physical_type.columns;
  				cols = physical_type.vecsize;
  				pack_pfx = "packed_rm_";
  			}
  			string base_type = physical_type.width == 16 ? "half" : "float";
  			string td_line = "typedef ";
  			td_line += "packed_" + base_type + to_string(rows);
  			td_line += " " + pack_pfx;
  			// Use the actual matrix size here.
  			td_line += base_type + to_string(physical_type.columns) + "x" + to_string(physical_type.vecsize);
  			td_line += "[" + to_string(cols) + "]";
  			td_line += ";";
  			add_typedef_line(td_line);
  		}
  		else if (!is_scalar(physical_type)) // scalar type is already packed.
  			pack_pfx = "packed_";
  	}
  	else if (row_major)
  	{
  		// Need to declare type with flipped vecsize/columns.
  		row_major_physical_type = physical_type;
  		swap(row_major_physical_type.vecsize, row_major_physical_type.columns);
  		declared_type = &row_major_physical_type;
  	}
  
  	// Very specifically, image load-store in argument buffers are disallowed on MSL on iOS.
  	if (msl_options.is_ios() && physical_type.basetype == SPIRType::Image && physical_type.image.sampled == 2)
  	{
  		if (!has_decoration(orig_id, DecorationNonWritable))
  			SPIRV_CROSS_THROW("Writable images are not allowed in argument buffers on iOS.");
  	}
  
  	// Array information is baked into these types.
  	string array_type;
  	if (physical_type.basetype != SPIRType::Image && physical_type.basetype != SPIRType::Sampler &&
  	    physical_type.basetype != SPIRType::SampledImage)
  	{
  		BuiltIn builtin = BuiltInMax;
  
  		// Special handling. In [[stage_out]] or [[stage_in]] blocks,
  		// we need flat arrays, but if we're somehow declaring gl_PerVertex for constant array reasons, we want
  		// template array types to be declared.
  		bool is_ib_in_out =
  				((stage_out_var_id && get_stage_out_struct_type().self == type.self &&
  				  variable_storage_requires_stage_io(StorageClassOutput)) ||
  				 (stage_in_var_id && get_stage_in_struct_type().self == type.self &&
  				  variable_storage_requires_stage_io(StorageClassInput)));
  		if (is_ib_in_out && is_member_builtin(type, index, &builtin))
  			is_using_builtin_array = true;
  		array_type = type_to_array_glsl(physical_type);
  	}
  
  	auto result = join(pack_pfx, type_to_glsl(*declared_type, orig_id), " ", qualifier, to_member_name(type, index),
  	                   member_attribute_qualifier(type, index), array_type, ";");
  
  	is_using_builtin_array = false;
  	return result;
  }
  
  // Emit a structure member, padding and packing to maintain the correct memeber alignments.
  void CompilerMSL::emit_struct_member(const SPIRType &type, uint32_t member_type_id, uint32_t index,
                                       const string &qualifier, uint32_t)
  {
  	// If this member requires padding to maintain its declared offset, emit a dummy padding member before it.
  	if (has_extended_member_decoration(type.self, index, SPIRVCrossDecorationPaddingTarget))
  	{
  		uint32_t pad_len = get_extended_member_decoration(type.self, index, SPIRVCrossDecorationPaddingTarget);
  		statement("char _m", index, "_pad", "[", pad_len, "];");
  	}
  
  	// Handle HLSL-style 0-based vertex/instance index.
  	builtin_declaration = true;
  	statement(to_struct_member(type, member_type_id, index, qualifier));
  	builtin_declaration = false;
  }
  
  void CompilerMSL::emit_struct_padding_target(const SPIRType &type)
  {
  	uint32_t struct_size = get_declared_struct_size_msl(type, true, true);
  	uint32_t target_size = get_extended_decoration(type.self, SPIRVCrossDecorationPaddingTarget);
  	if (target_size < struct_size)
  		SPIRV_CROSS_THROW("Cannot pad with negative bytes.");
  	else if (target_size > struct_size)
  		statement("char _m0_final_padding[", target_size - struct_size, "];");
  }
  
  // Return a MSL qualifier for the specified function attribute member
  string CompilerMSL::member_attribute_qualifier(const SPIRType &type, uint32_t index)
  {
  	auto &execution = get_entry_point();
  
  	uint32_t mbr_type_id = type.member_types[index];
  	auto &mbr_type = get<SPIRType>(mbr_type_id);
  
  	BuiltIn builtin = BuiltInMax;
  	bool is_builtin = is_member_builtin(type, index, &builtin);
  
  	if (has_extended_member_decoration(type.self, index, SPIRVCrossDecorationResourceIndexPrimary))
  	{
  		string quals = join(
  		    " [[id(", get_extended_member_decoration(type.self, index, SPIRVCrossDecorationResourceIndexPrimary), ")");
  		if (interlocked_resources.count(
  		        get_extended_member_decoration(type.self, index, SPIRVCrossDecorationInterfaceOrigID)))
  			quals += ", raster_order_group(0)";
  		quals += "]]";
  		return quals;
  	}
  
  	// Vertex function inputs
  	if (execution.model == ExecutionModelVertex && type.storage == StorageClassInput)
  	{
  		if (is_builtin)
  		{
  			switch (builtin)
  			{
  			case BuiltInVertexId:
  			case BuiltInVertexIndex:
  			case BuiltInBaseVertex:
  			case BuiltInInstanceId:
  			case BuiltInInstanceIndex:
  			case BuiltInBaseInstance:
  				if (msl_options.vertex_for_tessellation)
  					return "";
  				return string(" [[") + builtin_qualifier(builtin) + "]]";
  
  			case BuiltInDrawIndex:
  				SPIRV_CROSS_THROW("DrawIndex is not supported in MSL.");
  
  			default:
  				return "";
  			}
  		}
  
  		uint32_t locn;
  		if (is_builtin)
  			locn = get_or_allocate_builtin_input_member_location(builtin, type.self, index);
  		else
  			locn = get_member_location(type.self, index);
  
  		if (locn != k_unknown_location)
  			return string(" [[attribute(") + convert_to_string(locn) + ")]]";
  	}
  
  	// Vertex and tessellation evaluation function outputs
  	if (((execution.model == ExecutionModelVertex && !msl_options.vertex_for_tessellation) ||
  	     execution.model == ExecutionModelTessellationEvaluation) &&
  	    type.storage == StorageClassOutput)
  	{
  		if (is_builtin)
  		{
  			switch (builtin)
  			{
  			case BuiltInPointSize:
  				// Only mark the PointSize builtin if really rendering points.
  				// Some shaders may include a PointSize builtin even when used to render
  				// non-point topologies, and Metal will reject this builtin when compiling
  				// the shader into a render pipeline that uses a non-point topology.
  				return msl_options.enable_point_size_builtin ? (string(" [[") + builtin_qualifier(builtin) + "]]") : "";
  
  			case BuiltInViewportIndex:
  				if (!msl_options.supports_msl_version(2, 0))
  					SPIRV_CROSS_THROW("ViewportIndex requires Metal 2.0.");
  				/* fallthrough */
  			case BuiltInPosition:
  			case BuiltInLayer:
  				return string(" [[") + builtin_qualifier(builtin) + "]]" + (mbr_type.array.empty() ? "" : " ");
  
  			case BuiltInClipDistance:
  				if (has_member_decoration(type.self, index, DecorationIndex))
  					return join(" [[user(clip", get_member_decoration(type.self, index, DecorationIndex), ")]]");
  				else
  					return string(" [[") + builtin_qualifier(builtin) + "]]" + (mbr_type.array.empty() ? "" : " ");
  
  			case BuiltInCullDistance:
  				if (has_member_decoration(type.self, index, DecorationIndex))
  					return join(" [[user(cull", get_member_decoration(type.self, index, DecorationIndex), ")]]");
  				else
  					return string(" [[") + builtin_qualifier(builtin) + "]]" + (mbr_type.array.empty() ? "" : " ");
  
  			default:
  				return "";
  			}
  		}
  		uint32_t comp;
  		uint32_t locn = get_member_location(type.self, index, &comp);
  		if (locn != k_unknown_location)
  		{
  			if (comp != k_unknown_component)
  				return string(" [[user(locn") + convert_to_string(locn) + "_" + convert_to_string(comp) + ")]]";
  			else
  				return string(" [[user(locn") + convert_to_string(locn) + ")]]";
  		}
  	}
  
  	// Tessellation control function inputs
  	if (execution.model == ExecutionModelTessellationControl && type.storage == StorageClassInput)
  	{
  		if (is_builtin)
  		{
  			switch (builtin)
  			{
  			case BuiltInInvocationId:
  			case BuiltInPrimitiveId:
  				if (msl_options.multi_patch_workgroup)
  					return "";
  				return string(" [[") + builtin_qualifier(builtin) + "]]" + (mbr_type.array.empty() ? "" : " ");
  			case BuiltInSubgroupLocalInvocationId: // FIXME: Should work in any stage
  			case BuiltInSubgroupSize: // FIXME: Should work in any stage
  				if (msl_options.emulate_subgroups)
  					return "";
  				return string(" [[") + builtin_qualifier(builtin) + "]]" + (mbr_type.array.empty() ? "" : " ");
  			case BuiltInPatchVertices:
  				return "";
  			// Others come from stage input.
  			default:
  				break;
  			}
  		}
  		if (msl_options.multi_patch_workgroup)
  			return "";
  
  		uint32_t locn;
  		if (is_builtin)
  			locn = get_or_allocate_builtin_input_member_location(builtin, type.self, index);
  		else
  			locn = get_member_location(type.self, index);
  
  		if (locn != k_unknown_location)
  			return string(" [[attribute(") + convert_to_string(locn) + ")]]";
  	}
  
  	// Tessellation control function outputs
  	if (execution.model == ExecutionModelTessellationControl && type.storage == StorageClassOutput)
  	{
  		// For this type of shader, we always arrange for it to capture its
  		// output to a buffer. For this reason, qualifiers are irrelevant here.
  		return "";
  	}
  
  	// Tessellation evaluation function inputs
  	if (execution.model == ExecutionModelTessellationEvaluation && type.storage == StorageClassInput)
  	{
  		if (is_builtin)
  		{
  			switch (builtin)
  			{
  			case BuiltInPrimitiveId:
  			case BuiltInTessCoord:
  				return string(" [[") + builtin_qualifier(builtin) + "]]";
  			case BuiltInPatchVertices:
  				return "";
  			// Others come from stage input.
  			default:
  				break;
  			}
  		}
  		// The special control point array must not be marked with an attribute.
  		if (get_type(type.member_types[index]).basetype == SPIRType::ControlPointArray)
  			return "";
  
  		uint32_t locn;
  		if (is_builtin)
  			locn = get_or_allocate_builtin_input_member_location(builtin, type.self, index);
  		else
  			locn = get_member_location(type.self, index);
  
  		if (locn != k_unknown_location)
  			return string(" [[attribute(") + convert_to_string(locn) + ")]]";
  	}
  
  	// Tessellation evaluation function outputs were handled above.
  
  	// Fragment function inputs
  	if (execution.model == ExecutionModelFragment && type.storage == StorageClassInput)
  	{
  		string quals;
  		if (is_builtin)
  		{
  			switch (builtin)
  			{
  			case BuiltInViewIndex:
  				if (!msl_options.multiview || !msl_options.multiview_layered_rendering)
  					break;
  				/* fallthrough */
  			case BuiltInFrontFacing:
  			case BuiltInPointCoord:
  			case BuiltInFragCoord:
  			case BuiltInSampleId:
  			case BuiltInSampleMask:
  			case BuiltInLayer:
  			case BuiltInBaryCoordNV:
  			case BuiltInBaryCoordNoPerspNV:
  				quals = builtin_qualifier(builtin);
  				break;
  
  			case BuiltInClipDistance:
  				return join(" [[user(clip", get_member_decoration(type.self, index, DecorationIndex), ")]]");
  			case BuiltInCullDistance:
  				return join(" [[user(cull", get_member_decoration(type.self, index, DecorationIndex), ")]]");
  
  			default:
  				break;
  			}
  		}
  		else
  		{
  			uint32_t comp;
  			uint32_t locn = get_member_location(type.self, index, &comp);
  			if (locn != k_unknown_location)
  			{
  				// For user-defined attributes, this is fine. From Vulkan spec:
  				// A user-defined output variable is considered to match an input variable in the subsequent stage if
  				// the two variables are declared with the same Location and Component decoration and match in type
  				// and decoration, except that interpolation decorations are not required to match. For the purposes
  				// of interface matching, variables declared without a Component decoration are considered to have a
  				// Component decoration of zero.
  
  				if (comp != k_unknown_component && comp != 0)
  					quals = string("user(locn") + convert_to_string(locn) + "_" + convert_to_string(comp) + ")";
  				else
  					quals = string("user(locn") + convert_to_string(locn) + ")";
  			}
  		}
  
  		if (builtin == BuiltInBaryCoordNV || builtin == BuiltInBaryCoordNoPerspNV)
  		{
  			if (has_member_decoration(type.self, index, DecorationFlat) ||
  			    has_member_decoration(type.self, index, DecorationCentroid) ||
  			    has_member_decoration(type.self, index, DecorationSample) ||
  			    has_member_decoration(type.self, index, DecorationNoPerspective))
  			{
  				// NoPerspective is baked into the builtin type.
  				SPIRV_CROSS_THROW(
  				    "Flat, Centroid, Sample, NoPerspective decorations are not supported for BaryCoord inputs.");
  			}
  		}
  
  		// Don't bother decorating integers with the 'flat' attribute; it's
  		// the default (in fact, the only option). Also don't bother with the
  		// FragCoord builtin; it's always noperspective on Metal.
  		if (!type_is_integral(mbr_type) && (!is_builtin || builtin != BuiltInFragCoord))
  		{
  			if (has_member_decoration(type.self, index, DecorationFlat))
  			{
  				if (!quals.empty())
  					quals += ", ";
  				quals += "flat";
  			}
  			else if (has_member_decoration(type.self, index, DecorationCentroid))
  			{
  				if (!quals.empty())
  					quals += ", ";
  				if (has_member_decoration(type.self, index, DecorationNoPerspective))
  					quals += "centroid_no_perspective";
  				else
  					quals += "centroid_perspective";
  			}
  			else if (has_member_decoration(type.self, index, DecorationSample))
  			{
  				if (!quals.empty())
  					quals += ", ";
  				if (has_member_decoration(type.self, index, DecorationNoPerspective))
  					quals += "sample_no_perspective";
  				else
  					quals += "sample_perspective";
  			}
  			else if (has_member_decoration(type.self, index, DecorationNoPerspective))
  			{
  				if (!quals.empty())
  					quals += ", ";
  				quals += "center_no_perspective";
  			}
  		}
  
  		if (!quals.empty())
  			return " [[" + quals + "]]";
  	}
  
  	// Fragment function outputs
  	if (execution.model == ExecutionModelFragment && type.storage == StorageClassOutput)
  	{
  		if (is_builtin)
  		{
  			switch (builtin)
  			{
  			case BuiltInFragStencilRefEXT:
  				// Similar to PointSize, only mark FragStencilRef if there's a stencil buffer.
  				// Some shaders may include a FragStencilRef builtin even when used to render
  				// without a stencil attachment, and Metal will reject this builtin
  				// when compiling the shader into a render pipeline that does not set
  				// stencilAttachmentPixelFormat.
  				if (!msl_options.enable_frag_stencil_ref_builtin)
  					return "";
  				if (!msl_options.supports_msl_version(2, 1))
  					SPIRV_CROSS_THROW("Stencil export only supported in MSL 2.1 and up.");
  				return string(" [[") + builtin_qualifier(builtin) + "]]";
  
  			case BuiltInFragDepth:
  				// Ditto FragDepth.
  				if (!msl_options.enable_frag_depth_builtin)
  					return "";
  				/* fallthrough */
  			case BuiltInSampleMask:
  				return string(" [[") + builtin_qualifier(builtin) + "]]";
  
  			default:
  				return "";
  			}
  		}
  		uint32_t locn = get_member_location(type.self, index);
  		// Metal will likely complain about missing color attachments, too.
  		if (locn != k_unknown_location && !(msl_options.enable_frag_output_mask & (1 << locn)))
  			return "";
  		if (locn != k_unknown_location && has_member_decoration(type.self, index, DecorationIndex))
  			return join(" [[color(", locn, "), index(", get_member_decoration(type.self, index, DecorationIndex),
  			            ")]]");
  		else if (locn != k_unknown_location)
  			return join(" [[color(", locn, ")]]");
  		else if (has_member_decoration(type.self, index, DecorationIndex))
  			return join(" [[index(", get_member_decoration(type.self, index, DecorationIndex), ")]]");
  		else
  			return "";
  	}
  
  	// Compute function inputs
  	if (execution.model == ExecutionModelGLCompute && type.storage == StorageClassInput)
  	{
  		if (is_builtin)
  		{
  			switch (builtin)
  			{
  			case BuiltInNumSubgroups:
  			case BuiltInSubgroupId:
  			case BuiltInSubgroupLocalInvocationId: // FIXME: Should work in any stage
  			case BuiltInSubgroupSize: // FIXME: Should work in any stage
  				if (msl_options.emulate_subgroups)
  					break;
  				/* fallthrough */
  			case BuiltInGlobalInvocationId:
  			case BuiltInWorkgroupId:
  			case BuiltInNumWorkgroups:
  			case BuiltInLocalInvocationId:
  			case BuiltInLocalInvocationIndex:
  				return string(" [[") + builtin_qualifier(builtin) + "]]";
  
  			default:
  				return "";
  			}
  		}
  	}
  
  	return "";
  }
  
  // Returns the location decoration of the member with the specified index in the specified type.
  // If the location of the member has been explicitly set, that location is used. If not, this
  // function assumes the members are ordered in their location order, and simply returns the
  // index as the location.
  uint32_t CompilerMSL::get_member_location(uint32_t type_id, uint32_t index, uint32_t *comp) const
  {
  	if (comp)
  	{
  		if (has_member_decoration(type_id, index, DecorationComponent))
  			*comp = get_member_decoration(type_id, index, DecorationComponent);
  		else
  			*comp = k_unknown_component;
  	}
  
  	if (has_member_decoration(type_id, index, DecorationLocation))
  		return get_member_decoration(type_id, index, DecorationLocation);
  	else
  		return k_unknown_location;
  }
  
  uint32_t CompilerMSL::get_or_allocate_builtin_input_member_location(spv::BuiltIn builtin,
                                                                      uint32_t type_id, uint32_t index,
                                                                      uint32_t *comp)
  {
  	uint32_t loc = get_member_location(type_id, index, comp);
  	if (loc != k_unknown_location)
  		return loc;
  
  	if (comp)
  		*comp = k_unknown_component;
  
  	// Late allocation. Find a location which is unused by the application.
  	// This can happen for built-in inputs in tessellation which are mixed and matched with user inputs.
  	auto &mbr_type = get<SPIRType>(get<SPIRType>(type_id).member_types[index]);
  	uint32_t count = type_to_location_count(mbr_type);
  
  	loc = 0;
  
  	const auto location_range_in_use = [this](uint32_t location, uint32_t location_count) -> bool {
  		for (uint32_t i = 0; i < location_count; i++)
  			if (location_inputs_in_use.count(location + i) != 0)
  				return true;
  		return false;
  	};
  
  	while (location_range_in_use(loc, count))
  		loc++;
  
  	set_member_decoration(type_id, index, DecorationLocation, loc);
  
  	// Triangle tess level inputs are shared in one packed float4,
  	// mark both builtins as sharing one location.
  	if (get_execution_mode_bitset().get(ExecutionModeTriangles) &&
  	    (builtin == BuiltInTessLevelInner || builtin == BuiltInTessLevelOuter))
  	{
  		builtin_to_automatic_input_location[BuiltInTessLevelInner] = loc;
  		builtin_to_automatic_input_location[BuiltInTessLevelOuter] = loc;
  	}
  	else
  		builtin_to_automatic_input_location[builtin] = loc;
  
  	mark_location_as_used_by_shader(loc, mbr_type, StorageClassInput, true);
  	return loc;
  }
  
  // Returns the type declaration for a function, including the
  // entry type if the current function is the entry point function
  string CompilerMSL::func_type_decl(SPIRType &type)
  {
  	// The regular function return type. If not processing the entry point function, that's all we need
  	string return_type = type_to_glsl(type) + type_to_array_glsl(type);
  	if (!processing_entry_point)
  		return return_type;
  
  	// If an outgoing interface block has been defined, and it should be returned, override the entry point return type
  	bool ep_should_return_output = !get_is_rasterization_disabled();
  	if (stage_out_var_id && ep_should_return_output)
  		return_type = type_to_glsl(get_stage_out_struct_type()) + type_to_array_glsl(type);
  
  	// Prepend a entry type, based on the execution model
  	string entry_type;
  	auto &execution = get_entry_point();
  	switch (execution.model)
  	{
  	case ExecutionModelVertex:
  		if (msl_options.vertex_for_tessellation && !msl_options.supports_msl_version(1, 2))
  			SPIRV_CROSS_THROW("Tessellation requires Metal 1.2.");
  		entry_type = msl_options.vertex_for_tessellation ? "kernel" : "vertex";
  		break;
  	case ExecutionModelTessellationEvaluation:
  		if (!msl_options.supports_msl_version(1, 2))
  			SPIRV_CROSS_THROW("Tessellation requires Metal 1.2.");
  		if (execution.flags.get(ExecutionModeIsolines))
  			SPIRV_CROSS_THROW("Metal does not support isoline tessellation.");
  		if (msl_options.is_ios())
  			entry_type =
  			    join("[[ patch(", execution.flags.get(ExecutionModeTriangles) ? "triangle" : "quad", ") ]] vertex");
  		else
  			entry_type = join("[[ patch(", execution.flags.get(ExecutionModeTriangles) ? "triangle" : "quad", ", ",
  			                  execution.output_vertices, ") ]] vertex");
  		break;
  	case ExecutionModelFragment:
  		entry_type = execution.flags.get(ExecutionModeEarlyFragmentTests) ||
  		                     execution.flags.get(ExecutionModePostDepthCoverage) ?
  		                 "[[ early_fragment_tests ]] fragment" :
  		                 "fragment";
  		break;
  	case ExecutionModelTessellationControl:
  		if (!msl_options.supports_msl_version(1, 2))
  			SPIRV_CROSS_THROW("Tessellation requires Metal 1.2.");
  		if (execution.flags.get(ExecutionModeIsolines))
  			SPIRV_CROSS_THROW("Metal does not support isoline tessellation.");
  		/* fallthrough */
  	case ExecutionModelGLCompute:
  	case ExecutionModelKernel:
  		entry_type = "kernel";
  		break;
  	default:
  		entry_type = "unknown";
  		break;
  	}
  
  	return entry_type + " " + return_type;
  }
  
  // In MSL, address space qualifiers are required for all pointer or reference variables
  string CompilerMSL::get_argument_address_space(const SPIRVariable &argument)
  {
  	const auto &type = get<SPIRType>(argument.basetype);
  	return get_type_address_space(type, argument.self, true);
  }
  
  string CompilerMSL::get_type_address_space(const SPIRType &type, uint32_t id, bool argument)
  {
  	// This can be called for variable pointer contexts as well, so be very careful about which method we choose.
  	Bitset flags;
  	auto *var = maybe_get<SPIRVariable>(id);
  	if (var && type.basetype == SPIRType::Struct &&
  	    (has_decoration(type.self, DecorationBlock) || has_decoration(type.self, DecorationBufferBlock)))
  		flags = get_buffer_block_flags(id);
  	else
  		flags = get_decoration_bitset(id);
  
  	const char *addr_space = nullptr;
  	switch (type.storage)
  	{
  	case StorageClassWorkgroup:
  		addr_space = "threadgroup";
  		break;
  
  	case StorageClassStorageBuffer:
  	{
  		// For arguments from variable pointers, we use the write count deduction, so
  		// we should not assume any constness here. Only for global SSBOs.
  		bool readonly = false;
  		if (!var || has_decoration(type.self, DecorationBlock))
  			readonly = flags.get(DecorationNonWritable);
  
  		addr_space = readonly ? "const device" : "device";
  		break;
  	}
  
  	case StorageClassUniform:
  	case StorageClassUniformConstant:
  	case StorageClassPushConstant:
  		if (type.basetype == SPIRType::Struct)
  		{
  			bool ssbo = has_decoration(type.self, DecorationBufferBlock);
  			if (ssbo)
  				addr_space = flags.get(DecorationNonWritable) ? "const device" : "device";
  			else
  				addr_space = "constant";
  		}
  		else if (!argument)
  		{
  			addr_space = "constant";
  		}
  		else if (type_is_msl_framebuffer_fetch(type))
  		{
  			// Subpass inputs are passed around by value.
  			addr_space = "";
  		}
  		break;
  
  	case StorageClassFunction:
  	case StorageClassGeneric:
  		break;
  
  	case StorageClassInput:
  		if (get_execution_model() == ExecutionModelTessellationControl && var &&
  		    var->basevariable == stage_in_ptr_var_id)
  			addr_space = msl_options.multi_patch_workgroup ? "constant" : "threadgroup";
  		if (get_execution_model() == ExecutionModelFragment && var && var->basevariable == stage_in_var_id)
  			addr_space = "thread";
  		break;
  
  	case StorageClassOutput:
  		if (capture_output_to_buffer)
  		{
  			if (var && type.storage == StorageClassOutput)
  			{
  				bool is_masked = is_stage_output_variable_masked(*var);
  
  				if (is_masked)
  				{
  					if (is_tessellation_shader())
  						addr_space = "threadgroup";
  					else
  						addr_space = "thread";
  				}
  				else if (variable_decl_is_remapped_storage(*var, StorageClassWorkgroup))
  					addr_space = "threadgroup";
  			}
  
  			if (!addr_space)
  				addr_space = "device";
  		}
  		break;
  
  	default:
  		break;
  	}
  
  	if (!addr_space)
  	{
  		// No address space for plain values.
  		addr_space = type.pointer || (argument && type.basetype == SPIRType::ControlPointArray) ? "thread" : "";
  	}
  
  	return join(flags.get(DecorationVolatile) || flags.get(DecorationCoherent) ? "volatile " : "", addr_space);
  }
  
  const char *CompilerMSL::to_restrict(uint32_t id, bool space)
  {
  	// This can be called for variable pointer contexts as well, so be very careful about which method we choose.
  	Bitset flags;
  	if (ir.ids[id].get_type() == TypeVariable)
  	{
  		uint32_t type_id = expression_type_id(id);
  		auto &type = expression_type(id);
  		if (type.basetype == SPIRType::Struct &&
  		    (has_decoration(type_id, DecorationBlock) || has_decoration(type_id, DecorationBufferBlock)))
  			flags = get_buffer_block_flags(id);
  		else
  			flags = get_decoration_bitset(id);
  	}
  	else
  		flags = get_decoration_bitset(id);
  
  	return flags.get(DecorationRestrict) ? (space ? "restrict " : "restrict") : "";
  }
  
  string CompilerMSL::entry_point_arg_stage_in()
  {
  	string decl;
  
  	if (get_execution_model() == ExecutionModelTessellationControl && msl_options.multi_patch_workgroup)
  		return decl;
  
  	// Stage-in structure
  	uint32_t stage_in_id;
  	if (get_execution_model() == ExecutionModelTessellationEvaluation)
  		stage_in_id = patch_stage_in_var_id;
  	else
  		stage_in_id = stage_in_var_id;
  
  	if (stage_in_id)
  	{
  		auto &var = get<SPIRVariable>(stage_in_id);
  		auto &type = get_variable_data_type(var);
  
  		add_resource_name(var.self);
  		decl = join(type_to_glsl(type), " ", to_name(var.self), " [[stage_in]]");
  	}
  
  	return decl;
  }
  
  // Returns true if this input builtin should be a direct parameter on a shader function parameter list,
  // and false for builtins that should be passed or calculated some other way.
  bool CompilerMSL::is_direct_input_builtin(BuiltIn bi_type)
  {
  	switch (bi_type)
  	{
  	// Vertex function in
  	case BuiltInVertexId:
  	case BuiltInVertexIndex:
  	case BuiltInBaseVertex:
  	case BuiltInInstanceId:
  	case BuiltInInstanceIndex:
  	case BuiltInBaseInstance:
  		return get_execution_model() != ExecutionModelVertex || !msl_options.vertex_for_tessellation;
  	// Tess. control function in
  	case BuiltInPosition:
  	case BuiltInPointSize:
  	case BuiltInClipDistance:
  	case BuiltInCullDistance:
  	case BuiltInPatchVertices:
  		return false;
  	case BuiltInInvocationId:
  	case BuiltInPrimitiveId:
  		return get_execution_model() != ExecutionModelTessellationControl || !msl_options.multi_patch_workgroup;
  	// Tess. evaluation function in
  	case BuiltInTessLevelInner:
  	case BuiltInTessLevelOuter:
  		return false;
  	// Fragment function in
  	case BuiltInSamplePosition:
  	case BuiltInHelperInvocation:
  	case BuiltInBaryCoordNV:
  	case BuiltInBaryCoordNoPerspNV:
  		return false;
  	case BuiltInViewIndex:
  		return get_execution_model() == ExecutionModelFragment && msl_options.multiview &&
  		       msl_options.multiview_layered_rendering;
  	// Compute function in
  	case BuiltInSubgroupId:
  	case BuiltInNumSubgroups:
  		return !msl_options.emulate_subgroups;
  	// Any stage function in
  	case BuiltInDeviceIndex:
  	case BuiltInSubgroupEqMask:
  	case BuiltInSubgroupGeMask:
  	case BuiltInSubgroupGtMask:
  	case BuiltInSubgroupLeMask:
  	case BuiltInSubgroupLtMask:
  		return false;
  	case BuiltInSubgroupSize:
  		if (msl_options.fixed_subgroup_size != 0)
  			return false;
  		/* fallthrough */
  	case BuiltInSubgroupLocalInvocationId:
  		return !msl_options.emulate_subgroups;
  	default:
  		return true;
  	}
  }
  
  // Returns true if this is a fragment shader that runs per sample, and false otherwise.
  bool CompilerMSL::is_sample_rate() const
  {
  	auto &caps = get_declared_capabilities();
  	return get_execution_model() == ExecutionModelFragment &&
  	       (msl_options.force_sample_rate_shading ||
  	        std::find(caps.begin(), caps.end(), CapabilitySampleRateShading) != caps.end() ||
  	        (msl_options.use_framebuffer_fetch_subpasses && need_subpass_input));
  }
  
  void CompilerMSL::entry_point_args_builtin(string &ep_args)
  {
  	// Builtin variables
  	SmallVector<pair<SPIRVariable *, BuiltIn>, 8> active_builtins;
  	ir.for_each_typed_id<SPIRVariable>([&](uint32_t var_id, SPIRVariable &var) {
  		if (var.storage != StorageClassInput)
  			return;
  
  		auto bi_type = BuiltIn(get_decoration(var_id, DecorationBuiltIn));
  
  		// Don't emit SamplePosition as a separate parameter. In the entry
  		// point, we get that by calling get_sample_position() on the sample ID.
  		if (is_builtin_variable(var) &&
  		    get_variable_data_type(var).basetype != SPIRType::Struct &&
  		    get_variable_data_type(var).basetype != SPIRType::ControlPointArray)
  		{
  			// If the builtin is not part of the active input builtin set, don't emit it.
  			// Relevant for multiple entry-point modules which might declare unused builtins.
  			if (!active_input_builtins.get(bi_type) || !interface_variable_exists_in_entry_point(var_id))
  				return;
  
  			// Remember this variable. We may need to correct its type.
  			active_builtins.push_back(make_pair(&var, bi_type));
  
  			if (is_direct_input_builtin(bi_type))
  			{
  				if (!ep_args.empty())
  					ep_args += ", ";
  
  				// Handle HLSL-style 0-based vertex/instance index.
  				builtin_declaration = true;
  				ep_args += builtin_type_decl(bi_type, var_id) + " " + to_expression(var_id);
  				ep_args += " [[" + builtin_qualifier(bi_type);
  				if (bi_type == BuiltInSampleMask && get_entry_point().flags.get(ExecutionModePostDepthCoverage))
  				{
  					if (!msl_options.supports_msl_version(2))
  						SPIRV_CROSS_THROW("Post-depth coverage requires MSL 2.0.");
  					if (msl_options.is_macos() && !msl_options.supports_msl_version(2, 3))
  						SPIRV_CROSS_THROW("Post-depth coverage on Mac requires MSL 2.3.");
  					ep_args += ", post_depth_coverage";
  				}
  				ep_args += "]]";
  				builtin_declaration = false;
  			}
  		}
  
  		if (has_extended_decoration(var_id, SPIRVCrossDecorationBuiltInDispatchBase))
  		{
  			// This is a special implicit builtin, not corresponding to any SPIR-V builtin,
  			// which holds the base that was passed to vkCmdDispatchBase() or vkCmdDrawIndexed(). If it's present,
  			// assume we emitted it for a good reason.
  			assert(msl_options.supports_msl_version(1, 2));
  			if (!ep_args.empty())
  				ep_args += ", ";
  
  			ep_args += type_to_glsl(get_variable_data_type(var)) + " " + to_expression(var_id) + " [[grid_origin]]";
  		}
  
  		if (has_extended_decoration(var_id, SPIRVCrossDecorationBuiltInStageInputSize))
  		{
  			// This is another special implicit builtin, not corresponding to any SPIR-V builtin,
  			// which holds the number of vertices and instances to draw. If it's present,
  			// assume we emitted it for a good reason.
  			assert(msl_options.supports_msl_version(1, 2));
  			if (!ep_args.empty())
  				ep_args += ", ";
  
  			ep_args += type_to_glsl(get_variable_data_type(var)) + " " + to_expression(var_id) + " [[grid_size]]";
  		}
  	});
  
  	// Correct the types of all encountered active builtins. We couldn't do this before
  	// because ensure_correct_builtin_type() may increase the bound, which isn't allowed
  	// while iterating over IDs.
  	for (auto &var : active_builtins)
  		var.first->basetype = ensure_correct_builtin_type(var.first->basetype, var.second);
  
  	// Handle HLSL-style 0-based vertex/instance index.
  	if (needs_base_vertex_arg == TriState::Yes)
  		ep_args += built_in_func_arg(BuiltInBaseVertex, !ep_args.empty());
  
  	if (needs_base_instance_arg == TriState::Yes)
  		ep_args += built_in_func_arg(BuiltInBaseInstance, !ep_args.empty());
  
  	if (capture_output_to_buffer)
  	{
  		// Add parameters to hold the indirect draw parameters and the shader output. This has to be handled
  		// specially because it needs to be a pointer, not a reference.
  		if (stage_out_var_id)
  		{
  			if (!ep_args.empty())
  				ep_args += ", ";
  			ep_args += join("device ", type_to_glsl(get_stage_out_struct_type()), "* ", output_buffer_var_name,
  			                " [[buffer(", msl_options.shader_output_buffer_index, ")]]");
  		}
  
  		if (get_execution_model() == ExecutionModelTessellationControl)
  		{
  			if (!ep_args.empty())
  				ep_args += ", ";
  			ep_args +=
  			    join("constant uint* spvIndirectParams [[buffer(", msl_options.indirect_params_buffer_index, ")]]");
  		}
  		else if (stage_out_var_id &&
  		         !(get_execution_model() == ExecutionModelVertex && msl_options.vertex_for_tessellation))
  		{
  			if (!ep_args.empty())
  				ep_args += ", ";
  			ep_args +=
  			    join("device uint* spvIndirectParams [[buffer(", msl_options.indirect_params_buffer_index, ")]]");
  		}
  
  		if (get_execution_model() == ExecutionModelVertex && msl_options.vertex_for_tessellation &&
  		    (active_input_builtins.get(BuiltInVertexIndex) || active_input_builtins.get(BuiltInVertexId)) &&
  		    msl_options.vertex_index_type != Options::IndexType::None)
  		{
  			// Add the index buffer so we can set gl_VertexIndex correctly.
  			if (!ep_args.empty())
  				ep_args += ", ";
  			switch (msl_options.vertex_index_type)
  			{
  			case Options::IndexType::None:
  				break;
  			case Options::IndexType::UInt16:
  				ep_args += join("const device ushort* ", index_buffer_var_name, " [[buffer(",
  				                msl_options.shader_index_buffer_index, ")]]");
  				break;
  			case Options::IndexType::UInt32:
  				ep_args += join("const device uint* ", index_buffer_var_name, " [[buffer(",
  				                msl_options.shader_index_buffer_index, ")]]");
  				break;
  			}
  		}
  
  		// Tessellation control shaders get three additional parameters:
  		// a buffer to hold the per-patch data, a buffer to hold the per-patch
  		// tessellation levels, and a block of workgroup memory to hold the
  		// input control point data.
  		if (get_execution_model() == ExecutionModelTessellationControl)
  		{
  			if (patch_stage_out_var_id)
  			{
  				if (!ep_args.empty())
  					ep_args += ", ";
  				ep_args +=
  				    join("device ", type_to_glsl(get_patch_stage_out_struct_type()), "* ", patch_output_buffer_var_name,
  				         " [[buffer(", convert_to_string(msl_options.shader_patch_output_buffer_index), ")]]");
  			}
  			if (!ep_args.empty())
  				ep_args += ", ";
  			ep_args += join("device ", get_tess_factor_struct_name(), "* ", tess_factor_buffer_var_name, " [[buffer(",
  			                convert_to_string(msl_options.shader_tess_factor_buffer_index), ")]]");
  
  			// Initializer for tess factors must be handled specially since it's never declared as a normal variable.
  			uint32_t outer_factor_initializer_id = 0;
  			uint32_t inner_factor_initializer_id = 0;
  			ir.for_each_typed_id<SPIRVariable>([&](uint32_t, SPIRVariable &var) {
  				if (!has_decoration(var.self, DecorationBuiltIn) || var.storage != StorageClassOutput || !var.initializer)
  					return;
  
  				BuiltIn builtin = BuiltIn(get_decoration(var.self, DecorationBuiltIn));
  				if (builtin == BuiltInTessLevelInner)
  					inner_factor_initializer_id = var.initializer;
  				else if (builtin == BuiltInTessLevelOuter)
  					outer_factor_initializer_id = var.initializer;
  			});
  
  			const SPIRConstant *c = nullptr;
  
  			if (outer_factor_initializer_id && (c = maybe_get<SPIRConstant>(outer_factor_initializer_id)))
  			{
  				auto &entry_func = get<SPIRFunction>(ir.default_entry_point);
  				entry_func.fixup_hooks_in.push_back([=]() {
  					uint32_t components = get_execution_mode_bitset().get(ExecutionModeTriangles) ? 3 : 4;
  					for (uint32_t i = 0; i < components; i++)
  					{
  						statement(builtin_to_glsl(BuiltInTessLevelOuter, StorageClassOutput), "[", i, "] = ",
  						          "half(", to_expression(c->subconstants[i]), ");");
  					}
  				});
  			}
  
  			if (inner_factor_initializer_id && (c = maybe_get<SPIRConstant>(inner_factor_initializer_id)))
  			{
  				auto &entry_func = get<SPIRFunction>(ir.default_entry_point);
  				if (get_execution_mode_bitset().get(ExecutionModeTriangles))
  				{
  					entry_func.fixup_hooks_in.push_back([=]() {
  						statement(builtin_to_glsl(BuiltInTessLevelInner, StorageClassOutput), " = ", "half(",
  						          to_expression(c->subconstants[0]), ");");
  					});
  				}
  				else
  				{
  					entry_func.fixup_hooks_in.push_back([=]() {
  						for (uint32_t i = 0; i < 2; i++)
  						{
  							statement(builtin_to_glsl(BuiltInTessLevelInner, StorageClassOutput), "[", i, "] = ",
  							          "half(", to_expression(c->subconstants[i]), ");");
  						}
  					});
  				}
  			}
  
  			if (stage_in_var_id)
  			{
  				if (!ep_args.empty())
  					ep_args += ", ";
  				if (msl_options.multi_patch_workgroup)
  				{
  					ep_args += join("device ", type_to_glsl(get_stage_in_struct_type()), "* ", input_buffer_var_name,
  					                " [[buffer(", convert_to_string(msl_options.shader_input_buffer_index), ")]]");
  				}
  				else
  				{
  					ep_args += join("threadgroup ", type_to_glsl(get_stage_in_struct_type()), "* ", input_wg_var_name,
  					                " [[threadgroup(", convert_to_string(msl_options.shader_input_wg_index), ")]]");
  				}
  			}
  		}
  	}
  }
  
  string CompilerMSL::entry_point_args_argument_buffer(bool append_comma)
  {
  	string ep_args = entry_point_arg_stage_in();
  	Bitset claimed_bindings;
  
  	for (uint32_t i = 0; i < kMaxArgumentBuffers; i++)
  	{
  		uint32_t id = argument_buffer_ids[i];
  		if (id == 0)
  			continue;
  
  		add_resource_name(id);
  		auto &var = get<SPIRVariable>(id);
  		auto &type = get_variable_data_type(var);
  
  		if (!ep_args.empty())
  			ep_args += ", ";
  
  		// Check if the argument buffer binding itself has been remapped.
  		uint32_t buffer_binding;
  		auto itr = resource_bindings.find({ get_entry_point().model, i, kArgumentBufferBinding });
  		if (itr != end(resource_bindings))
  		{
  			buffer_binding = itr->second.first.msl_buffer;
  			itr->second.second = true;
  		}
  		else
  		{
  			// As a fallback, directly map desc set <-> binding.
  			// If that was taken, take the next buffer binding.
  			if (claimed_bindings.get(i))
  				buffer_binding = next_metal_resource_index_buffer;
  			else
  				buffer_binding = i;
  		}
  
  		claimed_bindings.set(buffer_binding);
  
  		ep_args += get_argument_address_space(var) + " " + type_to_glsl(type) + "& " + to_restrict(id) + to_name(id);
  		ep_args += " [[buffer(" + convert_to_string(buffer_binding) + ")]]";
  
  		next_metal_resource_index_buffer = max(next_metal_resource_index_buffer, buffer_binding + 1);
  	}
  
  	entry_point_args_discrete_descriptors(ep_args);
  	entry_point_args_builtin(ep_args);
  
  	if (!ep_args.empty() && append_comma)
  		ep_args += ", ";
  
  	return ep_args;
  }
  
  const MSLConstexprSampler *CompilerMSL::find_constexpr_sampler(uint32_t id) const
  {
  	// Try by ID.
  	{
  		auto itr = constexpr_samplers_by_id.find(id);
  		if (itr != end(constexpr_samplers_by_id))
  			return &itr->second;
  	}
  
  	// Try by binding.
  	{
  		uint32_t desc_set = get_decoration(id, DecorationDescriptorSet);
  		uint32_t binding = get_decoration(id, DecorationBinding);
  
  		auto itr = constexpr_samplers_by_binding.find({ desc_set, binding });
  		if (itr != end(constexpr_samplers_by_binding))
  			return &itr->second;
  	}
  
  	return nullptr;
  }
  
  void CompilerMSL::entry_point_args_discrete_descriptors(string &ep_args)
  {
  	// Output resources, sorted by resource index & type
  	// We need to sort to work around a bug on macOS 10.13 with NVidia drivers where switching between shaders
  	// with different order of buffers can result in issues with buffer assignments inside the driver.
  	struct Resource
  	{
  		SPIRVariable *var;
  		string name;
  		SPIRType::BaseType basetype;
  		uint32_t index;
  		uint32_t plane;
  		uint32_t secondary_index;
  	};
  
  	SmallVector<Resource> resources;
  
  	ir.for_each_typed_id<SPIRVariable>([&](uint32_t var_id, SPIRVariable &var) {
  		if ((var.storage == StorageClassUniform || var.storage == StorageClassUniformConstant ||
  		     var.storage == StorageClassPushConstant || var.storage == StorageClassStorageBuffer) &&
  		    !is_hidden_variable(var))
  		{
  			auto &type = get_variable_data_type(var);
  
  			if (is_supported_argument_buffer_type(type) && var.storage != StorageClassPushConstant)
  			{
  				uint32_t desc_set = get_decoration(var_id, DecorationDescriptorSet);
  				if (descriptor_set_is_argument_buffer(desc_set))
  					return;
  			}
  
  			const MSLConstexprSampler *constexpr_sampler = nullptr;
  			if (type.basetype == SPIRType::SampledImage || type.basetype == SPIRType::Sampler)
  			{
  				constexpr_sampler = find_constexpr_sampler(var_id);
  				if (constexpr_sampler)
  				{
  					// Mark this ID as a constexpr sampler for later in case it came from set/bindings.
  					constexpr_samplers_by_id[var_id] = *constexpr_sampler;
  				}
  			}
  
  			// Emulate texture2D atomic operations
  			uint32_t secondary_index = 0;
  			if (atomic_image_vars.count(var.self))
  			{
  				secondary_index = get_metal_resource_index(var, SPIRType::AtomicCounter, 0);
  			}
  
  			if (type.basetype == SPIRType::SampledImage)
  			{
  				add_resource_name(var_id);
  
  				uint32_t plane_count = 1;
  				if (constexpr_sampler && constexpr_sampler->ycbcr_conversion_enable)
  					plane_count = constexpr_sampler->planes;
  
  				for (uint32_t i = 0; i < plane_count; i++)
  					resources.push_back({ &var, to_name(var_id), SPIRType::Image,
  					                      get_metal_resource_index(var, SPIRType::Image, i), i, secondary_index });
  
  				if (type.image.dim != DimBuffer && !constexpr_sampler)
  				{
  					resources.push_back({ &var, to_sampler_expression(var_id), SPIRType::Sampler,
  					                      get_metal_resource_index(var, SPIRType::Sampler), 0, 0 });
  				}
  			}
  			else if (!constexpr_sampler)
  			{
  				// constexpr samplers are not declared as resources.
  				add_resource_name(var_id);
  				resources.push_back({ &var, to_name(var_id), type.basetype,
  				                      get_metal_resource_index(var, type.basetype), 0, secondary_index });
  			}
  		}
  	});
  
  	sort(resources.begin(), resources.end(), [](const Resource &lhs, const Resource &rhs) {
  		return tie(lhs.basetype, lhs.index) < tie(rhs.basetype, rhs.index);
  	});
  
  	for (auto &r : resources)
  	{
  		auto &var = *r.var;
  		auto &type = get_variable_data_type(var);
  
  		uint32_t var_id = var.self;
  
  		switch (r.basetype)
  		{
  		case SPIRType::Struct:
  		{
  			auto &m = ir.meta[type.self];
  			if (m.members.size() == 0)
  				break;
  			if (!type.array.empty())
  			{
  				if (type.array.size() > 1)
  					SPIRV_CROSS_THROW("Arrays of arrays of buffers are not supported.");
  
  				// Metal doesn't directly support this, so we must expand the
  				// array. We'll declare a local array to hold these elements
  				// later.
  				uint32_t array_size = to_array_size_literal(type);
  
  				if (array_size == 0)
  					SPIRV_CROSS_THROW("Unsized arrays of buffers are not supported in MSL.");
  
  				// Allow Metal to use the array<T> template to make arrays a value type
  				is_using_builtin_array = true;
  				buffer_arrays.push_back(var_id);
  				for (uint32_t i = 0; i < array_size; ++i)
  				{
  					if (!ep_args.empty())
  						ep_args += ", ";
  					ep_args += get_argument_address_space(var) + " " + type_to_glsl(type) + "* " + to_restrict(var_id) +
  					           r.name + "_" + convert_to_string(i);
  					ep_args += " [[buffer(" + convert_to_string(r.index + i) + ")";
  					if (interlocked_resources.count(var_id))
  						ep_args += ", raster_order_group(0)";
  					ep_args += "]]";
  				}
  				is_using_builtin_array = false;
  			}
  			else
  			{
  				if (!ep_args.empty())
  					ep_args += ", ";
  				ep_args +=
  				    get_argument_address_space(var) + " " + type_to_glsl(type) + "& " + to_restrict(var_id) + r.name;
  				ep_args += " [[buffer(" + convert_to_string(r.index) + ")";
  				if (interlocked_resources.count(var_id))
  					ep_args += ", raster_order_group(0)";
  				ep_args += "]]";
  			}
  			break;
  		}
  		case SPIRType::Sampler:
  			if (!ep_args.empty())
  				ep_args += ", ";
  			ep_args += sampler_type(type, var_id) + " " + r.name;
  			ep_args += " [[sampler(" + convert_to_string(r.index) + ")]]";
  			break;
  		case SPIRType::Image:
  		{
  			if (!ep_args.empty())
  				ep_args += ", ";
  
  			// Use Metal's native frame-buffer fetch API for subpass inputs.
  			const auto &basetype = get<SPIRType>(var.basetype);
  			if (!type_is_msl_framebuffer_fetch(basetype))
  			{
  				ep_args += image_type_glsl(type, var_id) + " " + r.name;
  				if (r.plane > 0)
  					ep_args += join(plane_name_suffix, r.plane);
  				ep_args += " [[texture(" + convert_to_string(r.index) + ")";
  				if (interlocked_resources.count(var_id))
  					ep_args += ", raster_order_group(0)";
  				ep_args += "]]";
  			}
  			else
  			{
  				if (msl_options.is_macos() && !msl_options.supports_msl_version(2, 3))
  					SPIRV_CROSS_THROW("Framebuffer fetch on Mac is not supported before MSL 2.3.");
  				ep_args += image_type_glsl(type, var_id) + " " + r.name;
  				ep_args += " [[color(" + convert_to_string(r.index) + ")]]";
  			}
  
  			// Emulate texture2D atomic operations
  			if (atomic_image_vars.count(var.self))
  			{
  				ep_args += ", device atomic_" + type_to_glsl(get<SPIRType>(basetype.image.type), 0);
  				ep_args += "* " + r.name + "_atomic";
  				ep_args += " [[buffer(" + convert_to_string(r.secondary_index) + ")";
  				if (interlocked_resources.count(var_id))
  					ep_args += ", raster_order_group(0)";
  				ep_args += "]]";
  			}
  			break;
  		}
  		default:
  			if (!ep_args.empty())
  				ep_args += ", ";
  			if (!type.pointer)
  				ep_args += get_type_address_space(get<SPIRType>(var.basetype), var_id) + " " +
  				           type_to_glsl(type, var_id) + "& " + r.name;
  			else
  				ep_args += type_to_glsl(type, var_id) + " " + r.name;
  			ep_args += " [[buffer(" + convert_to_string(r.index) + ")";
  			if (interlocked_resources.count(var_id))
  				ep_args += ", raster_order_group(0)";
  			ep_args += "]]";
  			break;
  		}
  	}
  }
  
  // Returns a string containing a comma-delimited list of args for the entry point function
  // This is the "classic" method of MSL 1 when we don't have argument buffer support.
  string CompilerMSL::entry_point_args_classic(bool append_comma)
  {
  	string ep_args = entry_point_arg_stage_in();
  	entry_point_args_discrete_descriptors(ep_args);
  	entry_point_args_builtin(ep_args);
  
  	if (!ep_args.empty() && append_comma)
  		ep_args += ", ";
  
  	return ep_args;
  }
  
  void CompilerMSL::fix_up_shader_inputs_outputs()
  {
  	auto &entry_func = this->get<SPIRFunction>(ir.default_entry_point);
  
  	// Emit a guard to ensure we don't execute beyond the last vertex.
  	// Vertex shaders shouldn't have the problems with barriers in non-uniform control flow that
  	// tessellation control shaders do, so early returns should be OK. We may need to revisit this
  	// if it ever becomes possible to use barriers from a vertex shader.
  	if (get_execution_model() == ExecutionModelVertex && msl_options.vertex_for_tessellation)
  	{
  		entry_func.fixup_hooks_in.push_back([this]() {
  			statement("if (any(", to_expression(builtin_invocation_id_id),
  			          " >= ", to_expression(builtin_stage_input_size_id), "))");
  			statement("    return;");
  		});
  	}
  
  	// Look for sampled images and buffer. Add hooks to set up the swizzle constants or array lengths.
  	ir.for_each_typed_id<SPIRVariable>([&](uint32_t, SPIRVariable &var) {
  		auto &type = get_variable_data_type(var);
  		uint32_t var_id = var.self;
  		bool ssbo = has_decoration(type.self, DecorationBufferBlock);
  
  		if (var.storage == StorageClassUniformConstant && !is_hidden_variable(var))
  		{
  			if (msl_options.swizzle_texture_samples && has_sampled_images && is_sampled_image_type(type))
  			{
  				entry_func.fixup_hooks_in.push_back([this, &type, &var, var_id]() {
  					bool is_array_type = !type.array.empty();
  
  					uint32_t desc_set = get_decoration(var_id, DecorationDescriptorSet);
  					if (descriptor_set_is_argument_buffer(desc_set))
  					{
  						statement("constant uint", is_array_type ? "* " : "& ", to_swizzle_expression(var_id),
  						          is_array_type ? " = &" : " = ", to_name(argument_buffer_ids[desc_set]),
  						          ".spvSwizzleConstants", "[",
  						          convert_to_string(get_metal_resource_index(var, SPIRType::Image)), "];");
  					}
  					else
  					{
  						// If we have an array of images, we need to be able to index into it, so take a pointer instead.
  						statement("constant uint", is_array_type ? "* " : "& ", to_swizzle_expression(var_id),
  						          is_array_type ? " = &" : " = ", to_name(swizzle_buffer_id), "[",
  						          convert_to_string(get_metal_resource_index(var, SPIRType::Image)), "];");
  					}
  				});
  			}
  		}
  		else if ((var.storage == StorageClassStorageBuffer || (var.storage == StorageClassUniform && ssbo)) &&
  		         !is_hidden_variable(var))
  		{
  			if (buffers_requiring_array_length.count(var.self))
  			{
  				entry_func.fixup_hooks_in.push_back([this, &type, &var, var_id]() {
  					bool is_array_type = !type.array.empty();
  
  					uint32_t desc_set = get_decoration(var_id, DecorationDescriptorSet);
  					if (descriptor_set_is_argument_buffer(desc_set))
  					{
  						statement("constant uint", is_array_type ? "* " : "& ", to_buffer_size_expression(var_id),
  						          is_array_type ? " = &" : " = ", to_name(argument_buffer_ids[desc_set]),
  						          ".spvBufferSizeConstants", "[",
  						          convert_to_string(get_metal_resource_index(var, SPIRType::Image)), "];");
  					}
  					else
  					{
  						// If we have an array of images, we need to be able to index into it, so take a pointer instead.
  						statement("constant uint", is_array_type ? "* " : "& ", to_buffer_size_expression(var_id),
  						          is_array_type ? " = &" : " = ", to_name(buffer_size_buffer_id), "[",
  						          convert_to_string(get_metal_resource_index(var, type.basetype)), "];");
  					}
  				});
  			}
  		}
  	});
  
  	// Builtin variables
  	ir.for_each_typed_id<SPIRVariable>([this, &entry_func](uint32_t, SPIRVariable &var) {
  		uint32_t var_id = var.self;
  		BuiltIn bi_type = ir.meta[var_id].decoration.builtin_type;
  
  		if (var.storage != StorageClassInput && var.storage != StorageClassOutput)
  			return;
  		if (!interface_variable_exists_in_entry_point(var.self))
  			return;
  
  		if (var.storage == StorageClassInput && is_builtin_variable(var) && active_input_builtins.get(bi_type))
  		{
  			switch (bi_type)
  			{
  			case BuiltInSamplePosition:
  				entry_func.fixup_hooks_in.push_back([=]() {
  					statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = get_sample_position(",
  					          to_expression(builtin_sample_id_id), ");");
  				});
  				break;
  			case BuiltInFragCoord:
  				if (is_sample_rate())
  				{
  					entry_func.fixup_hooks_in.push_back([=]() {
  						statement(to_expression(var_id), ".xy += get_sample_position(",
  						          to_expression(builtin_sample_id_id), ") - 0.5;");
  					});
  				}
  				break;
  			case BuiltInHelperInvocation:
  				if (msl_options.is_ios() && !msl_options.supports_msl_version(2, 3))
  					SPIRV_CROSS_THROW("simd_is_helper_thread() requires version 2.3 on iOS.");
  				else if (msl_options.is_macos() && !msl_options.supports_msl_version(2, 1))
  					SPIRV_CROSS_THROW("simd_is_helper_thread() requires version 2.1 on macOS.");
  
  				entry_func.fixup_hooks_in.push_back([=]() {
  					statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = simd_is_helper_thread();");
  				});
  				break;
  			case BuiltInInvocationId:
  				// This is direct-mapped without multi-patch workgroups.
  				if (get_execution_model() != ExecutionModelTessellationControl || !msl_options.multi_patch_workgroup)
  					break;
  
  				entry_func.fixup_hooks_in.push_back([=]() {
  					statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = ",
  					          to_expression(builtin_invocation_id_id), ".x % ", this->get_entry_point().output_vertices,
  					          ";");
  				});
  				break;
  			case BuiltInPrimitiveId:
  				// This is natively supported by fragment and tessellation evaluation shaders.
  				// In tessellation control shaders, this is direct-mapped without multi-patch workgroups.
  				if (get_execution_model() != ExecutionModelTessellationControl || !msl_options.multi_patch_workgroup)
  					break;
  
  				entry_func.fixup_hooks_in.push_back([=]() {
  					statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = min(",
  					          to_expression(builtin_invocation_id_id), ".x / ", this->get_entry_point().output_vertices,
  					          ", spvIndirectParams[1] - 1);");
  				});
  				break;
  			case BuiltInPatchVertices:
  				if (get_execution_model() == ExecutionModelTessellationEvaluation)
  					entry_func.fixup_hooks_in.push_back([=]() {
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = ",
  						          to_expression(patch_stage_in_var_id), ".gl_in.size();");
  					});
  				else
  					entry_func.fixup_hooks_in.push_back([=]() {
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = spvIndirectParams[0];");
  					});
  				break;
  			case BuiltInTessCoord:
  				// Emit a fixup to account for the shifted domain. Don't do this for triangles;
  				// MoltenVK will just reverse the winding order instead.
  				if (msl_options.tess_domain_origin_lower_left && !get_entry_point().flags.get(ExecutionModeTriangles))
  				{
  					string tc = to_expression(var_id);
  					entry_func.fixup_hooks_in.push_back([=]() { statement(tc, ".y = 1.0 - ", tc, ".y;"); });
  				}
  				break;
  			case BuiltInSubgroupId:
  				if (!msl_options.emulate_subgroups)
  					break;
  				// For subgroup emulation, this is the same as the local invocation index.
  				entry_func.fixup_hooks_in.push_back([=]() {
  					statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = ",
  					          to_expression(builtin_local_invocation_index_id), ";");
  				});
  				break;
  			case BuiltInNumSubgroups:
  				if (!msl_options.emulate_subgroups)
  					break;
  				// For subgroup emulation, this is the same as the workgroup size.
  				entry_func.fixup_hooks_in.push_back([=]() {
  					auto &type = expression_type(builtin_workgroup_size_id);
  					string size_expr = to_expression(builtin_workgroup_size_id);
  					if (type.vecsize >= 3)
  						size_expr = join(size_expr, ".x * ", size_expr, ".y * ", size_expr, ".z");
  					else if (type.vecsize == 2)
  						size_expr = join(size_expr, ".x * ", size_expr, ".y");
  					statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = ", size_expr, ";");
  				});
  				break;
  			case BuiltInSubgroupLocalInvocationId:
  				if (!msl_options.emulate_subgroups)
  					break;
  				// For subgroup emulation, assume subgroups of size 1.
  				entry_func.fixup_hooks_in.push_back(
  				    [=]() { statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = 0;"); });
  				break;
  			case BuiltInSubgroupSize:
  				if (msl_options.emulate_subgroups)
  				{
  					// For subgroup emulation, assume subgroups of size 1.
  					entry_func.fixup_hooks_in.push_back(
  					    [=]() { statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = 1;"); });
  				}
  				else if (msl_options.fixed_subgroup_size != 0)
  				{
  					entry_func.fixup_hooks_in.push_back([=]() {
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = ",
  						          msl_options.fixed_subgroup_size, ";");
  					});
  				}
  				break;
  			case BuiltInSubgroupEqMask:
  				if (msl_options.is_ios() && !msl_options.supports_msl_version(2, 2))
  					SPIRV_CROSS_THROW("Subgroup ballot functionality requires Metal 2.2 on iOS.");
  				if (!msl_options.supports_msl_version(2, 1))
  					SPIRV_CROSS_THROW("Subgroup ballot functionality requires Metal 2.1.");
  				entry_func.fixup_hooks_in.push_back([=]() {
  					if (msl_options.is_ios())
  					{
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = ", "uint4(1 << ",
  						          to_expression(builtin_subgroup_invocation_id_id), ", uint3(0));");
  					}
  					else
  					{
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = ",
  						          to_expression(builtin_subgroup_invocation_id_id), " >= 32 ? uint4(0, (1 << (",
  						          to_expression(builtin_subgroup_invocation_id_id), " - 32)), uint2(0)) : uint4(1 << ",
  						          to_expression(builtin_subgroup_invocation_id_id), ", uint3(0));");
  					}
  				});
  				break;
  			case BuiltInSubgroupGeMask:
  				if (msl_options.is_ios() && !msl_options.supports_msl_version(2, 2))
  					SPIRV_CROSS_THROW("Subgroup ballot functionality requires Metal 2.2 on iOS.");
  				if (!msl_options.supports_msl_version(2, 1))
  					SPIRV_CROSS_THROW("Subgroup ballot functionality requires Metal 2.1.");
  				if (msl_options.fixed_subgroup_size != 0)
  					add_spv_func_and_recompile(SPVFuncImplSubgroupBallot);
  				entry_func.fixup_hooks_in.push_back([=]() {
  					// Case where index < 32, size < 32:
  					// mask0 = bfi(0, 0xFFFFFFFF, index, size - index);
  					// mask1 = bfi(0, 0xFFFFFFFF, 0, 0); // Gives 0
  					// Case where index < 32 but size >= 32:
  					// mask0 = bfi(0, 0xFFFFFFFF, index, 32 - index);
  					// mask1 = bfi(0, 0xFFFFFFFF, 0, size - 32);
  					// Case where index >= 32:
  					// mask0 = bfi(0, 0xFFFFFFFF, 32, 0); // Gives 0
  					// mask1 = bfi(0, 0xFFFFFFFF, index - 32, size - index);
  					// This is expressed without branches to avoid divergent
  					// control flow--hence the complicated min/max expressions.
  					// This is further complicated by the fact that if you attempt
  					// to bfi/bfe out-of-bounds on Metal, undefined behavior is the
  					// result.
  					if (msl_options.fixed_subgroup_size > 32)
  					{
  						// Don't use the subgroup size variable with fixed subgroup sizes,
  						// since the variables could be defined in the wrong order.
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id),
  						          " = uint4(insert_bits(0u, 0xFFFFFFFF, min(",
  						          to_expression(builtin_subgroup_invocation_id_id), ", 32u), (uint)max(32 - (int)",
  						          to_expression(builtin_subgroup_invocation_id_id),
  						          ", 0)), insert_bits(0u, 0xFFFFFFFF,"
  						          " (uint)max((int)",
  						          to_expression(builtin_subgroup_invocation_id_id), " - 32, 0), ",
  						          msl_options.fixed_subgroup_size, " - max(",
  						          to_expression(builtin_subgroup_invocation_id_id),
  						          ", 32u)), uint2(0));");
  					}
  					else if (msl_options.fixed_subgroup_size != 0)
  					{
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id),
  						          " = uint4(insert_bits(0u, 0xFFFFFFFF, ",
  						          to_expression(builtin_subgroup_invocation_id_id), ", ",
  						          msl_options.fixed_subgroup_size, " - ",
  						          to_expression(builtin_subgroup_invocation_id_id),
  						          "), uint3(0));");
  					}
  					else if (msl_options.is_ios())
  					{
  						// On iOS, the SIMD-group size will currently never exceed 32.
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id),
  						          " = uint4(insert_bits(0u, 0xFFFFFFFF, ",
  						          to_expression(builtin_subgroup_invocation_id_id), ", ",
  						          to_expression(builtin_subgroup_size_id), " - ",
  						          to_expression(builtin_subgroup_invocation_id_id), "), uint3(0));");
  					}
  					else
  					{
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id),
  						          " = uint4(insert_bits(0u, 0xFFFFFFFF, min(",
  						          to_expression(builtin_subgroup_invocation_id_id), ", 32u), (uint)max(min((int)",
  						          to_expression(builtin_subgroup_size_id), ", 32) - (int)",
  						          to_expression(builtin_subgroup_invocation_id_id),
  						          ", 0)), insert_bits(0u, 0xFFFFFFFF, (uint)max((int)",
  						          to_expression(builtin_subgroup_invocation_id_id), " - 32, 0), (uint)max((int)",
  						          to_expression(builtin_subgroup_size_id), " - (int)max(",
  						          to_expression(builtin_subgroup_invocation_id_id), ", 32u), 0)), uint2(0));");
  					}
  				});
  				break;
  			case BuiltInSubgroupGtMask:
  				if (msl_options.is_ios() && !msl_options.supports_msl_version(2, 2))
  					SPIRV_CROSS_THROW("Subgroup ballot functionality requires Metal 2.2 on iOS.");
  				if (!msl_options.supports_msl_version(2, 1))
  					SPIRV_CROSS_THROW("Subgroup ballot functionality requires Metal 2.1.");
  				add_spv_func_and_recompile(SPVFuncImplSubgroupBallot);
  				entry_func.fixup_hooks_in.push_back([=]() {
  					// The same logic applies here, except now the index is one
  					// more than the subgroup invocation ID.
  					if (msl_options.fixed_subgroup_size > 32)
  					{
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id),
  						          " = uint4(insert_bits(0u, 0xFFFFFFFF, min(",
  						          to_expression(builtin_subgroup_invocation_id_id), " + 1, 32u), (uint)max(32 - (int)",
  						          to_expression(builtin_subgroup_invocation_id_id),
  						          " - 1, 0)), insert_bits(0u, 0xFFFFFFFF, (uint)max((int)",
  						          to_expression(builtin_subgroup_invocation_id_id), " + 1 - 32, 0), ",
  						          msl_options.fixed_subgroup_size, " - max(",
  						          to_expression(builtin_subgroup_invocation_id_id),
  						          " + 1, 32u)), uint2(0));");
  					}
  					else if (msl_options.fixed_subgroup_size != 0)
  					{
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id),
  						          " = uint4(insert_bits(0u, 0xFFFFFFFF, ",
  						          to_expression(builtin_subgroup_invocation_id_id), " + 1, ",
  						          msl_options.fixed_subgroup_size, " - ",
  						          to_expression(builtin_subgroup_invocation_id_id),
  						          " - 1), uint3(0));");
  					}
  					else if (msl_options.is_ios())
  					{
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id),
  						          " = uint4(insert_bits(0u, 0xFFFFFFFF, ",
  						          to_expression(builtin_subgroup_invocation_id_id), " + 1, ",
  						          to_expression(builtin_subgroup_size_id), " - ",
  						          to_expression(builtin_subgroup_invocation_id_id), " - 1), uint3(0));");
  					}
  					else
  					{
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id),
  						          " = uint4(insert_bits(0u, 0xFFFFFFFF, min(",
  						          to_expression(builtin_subgroup_invocation_id_id), " + 1, 32u), (uint)max(min((int)",
  						          to_expression(builtin_subgroup_size_id), ", 32) - (int)",
  						          to_expression(builtin_subgroup_invocation_id_id),
  						          " - 1, 0)), insert_bits(0u, 0xFFFFFFFF, (uint)max((int)",
  						          to_expression(builtin_subgroup_invocation_id_id), " + 1 - 32, 0), (uint)max((int)",
  						          to_expression(builtin_subgroup_size_id), " - (int)max(",
  						          to_expression(builtin_subgroup_invocation_id_id), " + 1, 32u), 0)), uint2(0));");
  					}
  				});
  				break;
  			case BuiltInSubgroupLeMask:
  				if (msl_options.is_ios() && !msl_options.supports_msl_version(2, 2))
  					SPIRV_CROSS_THROW("Subgroup ballot functionality requires Metal 2.2 on iOS.");
  				if (!msl_options.supports_msl_version(2, 1))
  					SPIRV_CROSS_THROW("Subgroup ballot functionality requires Metal 2.1.");
  				add_spv_func_and_recompile(SPVFuncImplSubgroupBallot);
  				entry_func.fixup_hooks_in.push_back([=]() {
  					if (msl_options.is_ios())
  					{
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id),
  						          " = uint4(extract_bits(0xFFFFFFFF, 0, ",
  						          to_expression(builtin_subgroup_invocation_id_id), " + 1), uint3(0));");
  					}
  					else
  					{
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id),
  						          " = uint4(extract_bits(0xFFFFFFFF, 0, min(",
  						          to_expression(builtin_subgroup_invocation_id_id),
  						          " + 1, 32u)), extract_bits(0xFFFFFFFF, 0, (uint)max((int)",
  						          to_expression(builtin_subgroup_invocation_id_id), " + 1 - 32, 0)), uint2(0));");
  					}
  				});
  				break;
  			case BuiltInSubgroupLtMask:
  				if (msl_options.is_ios() && !msl_options.supports_msl_version(2, 2))
  					SPIRV_CROSS_THROW("Subgroup ballot functionality requires Metal 2.2 on iOS.");
  				if (!msl_options.supports_msl_version(2, 1))
  					SPIRV_CROSS_THROW("Subgroup ballot functionality requires Metal 2.1.");
  				add_spv_func_and_recompile(SPVFuncImplSubgroupBallot);
  				entry_func.fixup_hooks_in.push_back([=]() {
  					if (msl_options.is_ios())
  					{
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id),
  						          " = uint4(extract_bits(0xFFFFFFFF, 0, ",
  						          to_expression(builtin_subgroup_invocation_id_id), "), uint3(0));");
  					}
  					else
  					{
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id),
  						          " = uint4(extract_bits(0xFFFFFFFF, 0, min(",
  						          to_expression(builtin_subgroup_invocation_id_id),
  						          ", 32u)), extract_bits(0xFFFFFFFF, 0, (uint)max((int)",
  						          to_expression(builtin_subgroup_invocation_id_id), " - 32, 0)), uint2(0));");
  					}
  				});
  				break;
  			case BuiltInViewIndex:
  				if (!msl_options.multiview)
  				{
  					// According to the Vulkan spec, when not running under a multiview
  					// render pass, ViewIndex is 0.
  					entry_func.fixup_hooks_in.push_back([=]() {
  						statement("const ", builtin_type_decl(bi_type), " ", to_expression(var_id), " = 0;");
  					});
  				}
  				else if (msl_options.view_index_from_device_index)
  				{
  					// In this case, we take the view index from that of the device we're running on.
  					entry_func.fixup_hooks_in.push_back([=]() {
  						statement("const ", builtin_type_decl(bi_type), " ", to_expression(var_id), " = ",
  						          msl_options.device_index, ";");
  					});
  					// We actually don't want to set the render_target_array_index here.
  					// Since every physical device is rendering a different view,
  					// there's no need for layered rendering here.
  				}
  				else if (!msl_options.multiview_layered_rendering)
  				{
  					// In this case, the views are rendered one at a time. The view index, then,
  					// is just the first part of the "view mask".
  					entry_func.fixup_hooks_in.push_back([=]() {
  						statement("const ", builtin_type_decl(bi_type), " ", to_expression(var_id), " = ",
  						          to_expression(view_mask_buffer_id), "[0];");
  					});
  				}
  				else if (get_execution_model() == ExecutionModelFragment)
  				{
  					// Because we adjusted the view index in the vertex shader, we have to
  					// adjust it back here.
  					entry_func.fixup_hooks_in.push_back([=]() {
  						statement(to_expression(var_id), " += ", to_expression(view_mask_buffer_id), "[0];");
  					});
  				}
  				else if (get_execution_model() == ExecutionModelVertex)
  				{
  					// Metal provides no special support for multiview, so we smuggle
  					// the view index in the instance index.
  					entry_func.fixup_hooks_in.push_back([=]() {
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = ",
  						          to_expression(view_mask_buffer_id), "[0] + (", to_expression(builtin_instance_idx_id),
  						          " - ", to_expression(builtin_base_instance_id), ") % ",
  						          to_expression(view_mask_buffer_id), "[1];");
  						statement(to_expression(builtin_instance_idx_id), " = (",
  						          to_expression(builtin_instance_idx_id), " - ",
  						          to_expression(builtin_base_instance_id), ") / ", to_expression(view_mask_buffer_id),
  						          "[1] + ", to_expression(builtin_base_instance_id), ";");
  					});
  					// In addition to setting the variable itself, we also need to
  					// set the render_target_array_index with it on output. We have to
  					// offset this by the base view index, because Metal isn't in on
  					// our little game here.
  					entry_func.fixup_hooks_out.push_back([=]() {
  						statement(to_expression(builtin_layer_id), " = ", to_expression(var_id), " - ",
  						          to_expression(view_mask_buffer_id), "[0];");
  					});
  				}
  				break;
  			case BuiltInDeviceIndex:
  				// Metal pipelines belong to the devices which create them, so we'll
  				// need to create a MTLPipelineState for every MTLDevice in a grouped
  				// VkDevice. We can assume, then, that the device index is constant.
  				entry_func.fixup_hooks_in.push_back([=]() {
  					statement("const ", builtin_type_decl(bi_type), " ", to_expression(var_id), " = ",
  					          msl_options.device_index, ";");
  				});
  				break;
  			case BuiltInWorkgroupId:
  				if (!msl_options.dispatch_base || !active_input_builtins.get(BuiltInWorkgroupId))
  					break;
  
  				// The vkCmdDispatchBase() command lets the client set the base value
  				// of WorkgroupId. Metal has no direct equivalent; we must make this
  				// adjustment ourselves.
  				entry_func.fixup_hooks_in.push_back([=]() {
  					statement(to_expression(var_id), " += ", to_dereferenced_expression(builtin_dispatch_base_id), ";");
  				});
  				break;
  			case BuiltInGlobalInvocationId:
  				if (!msl_options.dispatch_base || !active_input_builtins.get(BuiltInGlobalInvocationId))
  					break;
  
  				// GlobalInvocationId is defined as LocalInvocationId + WorkgroupId * WorkgroupSize.
  				// This needs to be adjusted too.
  				entry_func.fixup_hooks_in.push_back([=]() {
  					auto &execution = this->get_entry_point();
  					uint32_t workgroup_size_id = execution.workgroup_size.constant;
  					if (workgroup_size_id)
  						statement(to_expression(var_id), " += ", to_dereferenced_expression(builtin_dispatch_base_id),
  						          " * ", to_expression(workgroup_size_id), ";");
  					else
  						statement(to_expression(var_id), " += ", to_dereferenced_expression(builtin_dispatch_base_id),
  						          " * uint3(", execution.workgroup_size.x, ", ", execution.workgroup_size.y, ", ",
  						          execution.workgroup_size.z, ");");
  				});
  				break;
  			case BuiltInVertexId:
  			case BuiltInVertexIndex:
  				// This is direct-mapped normally.
  				if (!msl_options.vertex_for_tessellation)
  					break;
  
  				entry_func.fixup_hooks_in.push_back([=]() {
  					builtin_declaration = true;
  					switch (msl_options.vertex_index_type)
  					{
  					case Options::IndexType::None:
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = ",
  						          to_expression(builtin_invocation_id_id), ".x + ",
  						          to_expression(builtin_dispatch_base_id), ".x;");
  						break;
  					case Options::IndexType::UInt16:
  					case Options::IndexType::UInt32:
  						statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = ", index_buffer_var_name,
  						          "[", to_expression(builtin_invocation_id_id), ".x] + ",
  						          to_expression(builtin_dispatch_base_id), ".x;");
  						break;
  					}
  					builtin_declaration = false;
  				});
  				break;
  			case BuiltInBaseVertex:
  				// This is direct-mapped normally.
  				if (!msl_options.vertex_for_tessellation)
  					break;
  
  				entry_func.fixup_hooks_in.push_back([=]() {
  					statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = ",
  					          to_expression(builtin_dispatch_base_id), ".x;");
  				});
  				break;
  			case BuiltInInstanceId:
  			case BuiltInInstanceIndex:
  				// This is direct-mapped normally.
  				if (!msl_options.vertex_for_tessellation)
  					break;
  
  				entry_func.fixup_hooks_in.push_back([=]() {
  					builtin_declaration = true;
  					statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = ",
  					          to_expression(builtin_invocation_id_id), ".y + ", to_expression(builtin_dispatch_base_id),
  					          ".y;");
  					builtin_declaration = false;
  				});
  				break;
  			case BuiltInBaseInstance:
  				// This is direct-mapped normally.
  				if (!msl_options.vertex_for_tessellation)
  					break;
  
  				entry_func.fixup_hooks_in.push_back([=]() {
  					statement(builtin_type_decl(bi_type), " ", to_expression(var_id), " = ",
  					          to_expression(builtin_dispatch_base_id), ".y;");
  				});
  				break;
  			default:
  				break;
  			}
  		}
  		else if (var.storage == StorageClassOutput && get_execution_model() == ExecutionModelFragment &&
  				 is_builtin_variable(var) && active_output_builtins.get(bi_type) &&
  				 bi_type == BuiltInSampleMask && has_additional_fixed_sample_mask())
  		{
  			// If the additional fixed sample mask was set, we need to adjust the sample_mask
  			// output to reflect that. If the shader outputs the sample_mask itself too, we need
  			// to AND the two masks to get the final one.
  			string op_str = does_shader_write_sample_mask ? " &= " : " = ";
  			entry_func.fixup_hooks_out.push_back([=]() {
  				statement(to_expression(builtin_sample_mask_id), op_str, additional_fixed_sample_mask_str(), ";");
  			});
  		}
  	});
  }
  
  // Returns the Metal index of the resource of the specified type as used by the specified variable.
  uint32_t CompilerMSL::get_metal_resource_index(SPIRVariable &var, SPIRType::BaseType basetype, uint32_t plane)
  {
  	auto &execution = get_entry_point();
  	auto &var_dec = ir.meta[var.self].decoration;
  	auto &var_type = get<SPIRType>(var.basetype);
  	uint32_t var_desc_set = (var.storage == StorageClassPushConstant) ? kPushConstDescSet : var_dec.set;
  	uint32_t var_binding = (var.storage == StorageClassPushConstant) ? kPushConstBinding : var_dec.binding;
  
  	// If a matching binding has been specified, find and use it.
  	auto itr = resource_bindings.find({ execution.model, var_desc_set, var_binding });
  
  	// Atomic helper buffers for image atomics need to use secondary bindings as well.
  	bool use_secondary_binding = (var_type.basetype == SPIRType::SampledImage && basetype == SPIRType::Sampler) ||
  	                             basetype == SPIRType::AtomicCounter;
  
  	auto resource_decoration =
  	    use_secondary_binding ? SPIRVCrossDecorationResourceIndexSecondary : SPIRVCrossDecorationResourceIndexPrimary;
  
  	if (plane == 1)
  		resource_decoration = SPIRVCrossDecorationResourceIndexTertiary;
  	if (plane == 2)
  		resource_decoration = SPIRVCrossDecorationResourceIndexQuaternary;
  
  	if (itr != end(resource_bindings))
  	{
  		auto &remap = itr->second;
  		remap.second = true;
  		switch (basetype)
  		{
  		case SPIRType::Image:
  			set_extended_decoration(var.self, resource_decoration, remap.first.msl_texture + plane);
  			return remap.first.msl_texture + plane;
  		case SPIRType::Sampler:
  			set_extended_decoration(var.self, resource_decoration, remap.first.msl_sampler);
  			return remap.first.msl_sampler;
  		default:
  			set_extended_decoration(var.self, resource_decoration, remap.first.msl_buffer);
  			return remap.first.msl_buffer;
  		}
  	}
  
  	// If we have already allocated an index, keep using it.
  	if (has_extended_decoration(var.self, resource_decoration))
  		return get_extended_decoration(var.self, resource_decoration);
  
  	auto &type = get<SPIRType>(var.basetype);
  
  	if (type_is_msl_framebuffer_fetch(type))
  	{
  		// Frame-buffer fetch gets its fallback resource index from the input attachment index,
  		// which is then treated as color index.
  		return get_decoration(var.self, DecorationInputAttachmentIndex);
  	}
  	else if (msl_options.enable_decoration_binding)
  	{
  		// Allow user to enable decoration binding.
  		// If there is no explicit mapping of bindings to MSL, use the declared binding as a fallback.
  		if (has_decoration(var.self, DecorationBinding))
  		{
  			var_binding = get_decoration(var.self, DecorationBinding);
  			// Avoid emitting sentinel bindings.
  			if (var_binding < 0x80000000u)
  				return var_binding;
  		}
  	}
  
  	// If we did not explicitly remap, allocate bindings on demand.
  	// We cannot reliably use Binding decorations since SPIR-V and MSL's binding models are very different.
  
  	bool allocate_argument_buffer_ids = false;
  
  	if (var.storage != StorageClassPushConstant)
  		allocate_argument_buffer_ids = descriptor_set_is_argument_buffer(var_desc_set);
  
  	uint32_t binding_stride = 1;
  	for (uint32_t i = 0; i < uint32_t(type.array.size()); i++)
  		binding_stride *= to_array_size_literal(type, i);
  
  	assert(binding_stride != 0);
  
  	// If a binding has not been specified, revert to incrementing resource indices.
  	uint32_t resource_index;
  
  	if (allocate_argument_buffer_ids)
  	{
  		// Allocate from a flat ID binding space.
  		resource_index = next_metal_resource_ids[var_desc_set];
  		next_metal_resource_ids[var_desc_set] += binding_stride;
  	}
  	else
  	{
  		// Allocate from plain bindings which are allocated per resource type.
  		switch (basetype)
  		{
  		case SPIRType::Image:
  			resource_index = next_metal_resource_index_texture;
  			next_metal_resource_index_texture += binding_stride;
  			break;
  		case SPIRType::Sampler:
  			resource_index = next_metal_resource_index_sampler;
  			next_metal_resource_index_sampler += binding_stride;
  			break;
  		default:
  			resource_index = next_metal_resource_index_buffer;
  			next_metal_resource_index_buffer += binding_stride;
  			break;
  		}
  	}
  
  	set_extended_decoration(var.self, resource_decoration, resource_index);
  	return resource_index;
  }
  
  bool CompilerMSL::type_is_msl_framebuffer_fetch(const SPIRType &type) const
  {
  	return type.basetype == SPIRType::Image && type.image.dim == DimSubpassData &&
  	       msl_options.use_framebuffer_fetch_subpasses;
  }
  
  bool CompilerMSL::type_is_pointer(const SPIRType &type) const
  {
  	if (!type.pointer)
  		return false;
  	auto &parent_type = get<SPIRType>(type.parent_type);
  	// Safeguards when we forget to set pointer_depth (there is an assert for it in type_to_glsl),
  	// but the extra check shouldn't hurt.
  	return (type.pointer_depth > parent_type.pointer_depth) || !parent_type.pointer;
  }
  
  bool CompilerMSL::type_is_pointer_to_pointer(const SPIRType &type) const
  {
  	if (!type.pointer)
  		return false;
  	auto &parent_type = get<SPIRType>(type.parent_type);
  	return type.pointer_depth > parent_type.pointer_depth && type_is_pointer(parent_type);
  }
  
  string CompilerMSL::argument_decl(const SPIRFunction::Parameter &arg)
  {
  	auto &var = get<SPIRVariable>(arg.id);
  	auto &type = get_variable_data_type(var);
  	auto &var_type = get<SPIRType>(arg.type);
  	StorageClass type_storage = var_type.storage;
  	bool is_pointer = var_type.pointer;
  
  	// If we need to modify the name of the variable, make sure we use the original variable.
  	// Our alias is just a shadow variable.
  	uint32_t name_id = var.self;
  	if (arg.alias_global_variable && var.basevariable)
  		name_id = var.basevariable;
  
  	bool constref = !arg.alias_global_variable && is_pointer && arg.write_count == 0;
  	// Framebuffer fetch is plain value, const looks out of place, but it is not wrong.
  	if (type_is_msl_framebuffer_fetch(type))
  		constref = false;
  
  	bool type_is_image = type.basetype == SPIRType::Image || type.basetype == SPIRType::SampledImage ||
  	                     type.basetype == SPIRType::Sampler;
  
  	// Arrays of images/samplers in MSL are always const.
  	if (!type.array.empty() && type_is_image)
  		constref = true;
  
  	const char *cv_qualifier = constref ? "const " : "";
  	string decl;
  
  	// If this is a combined image-sampler for a 2D image with floating-point type,
  	// we emitted the 'spvDynamicImageSampler' type, and this is *not* an alias parameter
  	// for a global, then we need to emit a "dynamic" combined image-sampler.
  	// Unfortunately, this is necessary to properly support passing around
  	// combined image-samplers with Y'CbCr conversions on them.
  	bool is_dynamic_img_sampler = !arg.alias_global_variable && type.basetype == SPIRType::SampledImage &&
  	                              type.image.dim == Dim2D && type_is_floating_point(get<SPIRType>(type.image.type)) &&
  	                              spv_function_implementations.count(SPVFuncImplDynamicImageSampler);
  
  	// Allow Metal to use the array<T> template to make arrays a value type
  	string address_space = get_argument_address_space(var);
  	bool builtin = has_decoration(var.self, DecorationBuiltIn);
  	auto builtin_type = BuiltIn(get_decoration(arg.id, DecorationBuiltIn));
  
  	if (address_space == "threadgroup")
  		is_using_builtin_array = true;
  
  	if (var.basevariable && (var.basevariable == stage_in_ptr_var_id || var.basevariable == stage_out_ptr_var_id))
  		decl = join(cv_qualifier, type_to_glsl(type, arg.id));
  	else if (builtin)
  	{
  		// Only use templated array for Clip/Cull distance when feasible.
  		// In other scenarios, we need need to override array length for tess levels (if used as outputs),
  		// or we need to emit the expected type for builtins (uint vs int).
  		auto storage = get<SPIRType>(var.basetype).storage;
  
  		if (storage == StorageClassInput &&
  		    (builtin_type == BuiltInTessLevelInner || builtin_type == BuiltInTessLevelOuter))
  		{
  			is_using_builtin_array = false;
  		}
  		else if (builtin_type != BuiltInClipDistance && builtin_type != BuiltInCullDistance)
  		{
  			is_using_builtin_array = true;
  		}
  
  		if (storage == StorageClassOutput && variable_storage_requires_stage_io(storage) &&
  		    !is_stage_output_builtin_masked(builtin_type))
  			is_using_builtin_array = true;
  
  		if (is_using_builtin_array)
  			decl = join(cv_qualifier, builtin_type_decl(builtin_type, arg.id));
  		else
  			decl = join(cv_qualifier, type_to_glsl(type, arg.id));
  	}
  	else if ((type_storage == StorageClassUniform || type_storage == StorageClassStorageBuffer) && is_array(type))
  	{
  		is_using_builtin_array = true;
  		decl += join(cv_qualifier, type_to_glsl(type, arg.id), "*");
  	}
  	else if (is_dynamic_img_sampler)
  	{
  		decl = join(cv_qualifier, "spvDynamicImageSampler<", type_to_glsl(get<SPIRType>(type.image.type)), ">");
  		// Mark the variable so that we can handle passing it to another function.
  		set_extended_decoration(arg.id, SPIRVCrossDecorationDynamicImageSampler);
  	}
  	else
  	{
  		// The type is a pointer type we need to emit cv_qualifier late.
  		if (type_is_pointer(type))
  		{
  			decl = type_to_glsl(type, arg.id);
  			if (*cv_qualifier != '\0')
  				decl += join(" ", cv_qualifier);
  		}
  		else
  			decl = join(cv_qualifier, type_to_glsl(type, arg.id));
  	}
  
  	bool opaque_handle = type_storage == StorageClassUniformConstant;
  
  	if (!builtin && !opaque_handle && !is_pointer &&
  	    (type_storage == StorageClassFunction || type_storage == StorageClassGeneric))
  	{
  		// If the argument is a pure value and not an opaque type, we will pass by value.
  		if (msl_options.force_native_arrays && is_array(type))
  		{
  			// We are receiving an array by value. This is problematic.
  			// We cannot be sure of the target address space since we are supposed to receive a copy,
  			// but this is not possible with MSL without some extra work.
  			// We will have to assume we're getting a reference in thread address space.
  			// If we happen to get a reference in constant address space, the caller must emit a copy and pass that.
  			// Thread const therefore becomes the only logical choice, since we cannot "create" a constant array from
  			// non-constant arrays, but we can create thread const from constant.
  			decl = string("thread const ") + decl;
  			decl += " (&";
  			const char *restrict_kw = to_restrict(name_id);
  			if (*restrict_kw)
  			{
  				decl += " ";
  				decl += restrict_kw;
  			}
  			decl += to_expression(name_id);
  			decl += ")";
  			decl += type_to_array_glsl(type);
  		}
  		else
  		{
  			if (!address_space.empty())
  				decl = join(address_space, " ", decl);
  			decl += " ";
  			decl += to_expression(name_id);
  		}
  	}
  	else if (is_array(type) && !type_is_image)
  	{
  		// Arrays of images and samplers are special cased.
  		if (!address_space.empty())
  			decl = join(address_space, " ", decl);
  
  		if (msl_options.argument_buffers)
  		{
  			uint32_t desc_set = get_decoration(name_id, DecorationDescriptorSet);
  			if ((type_storage == StorageClassUniform || type_storage == StorageClassStorageBuffer) &&
  			    descriptor_set_is_argument_buffer(desc_set))
  			{
  				// An awkward case where we need to emit *more* address space declarations (yay!).
  				// An example is where we pass down an array of buffer pointers to leaf functions.
  				// It's a constant array containing pointers to constants.
  				// The pointer array is always constant however. E.g.
  				// device SSBO * constant (&array)[N].
  				// const device SSBO * constant (&array)[N].
  				// constant SSBO * constant (&array)[N].
  				// However, this only matters for argument buffers, since for MSL 1.0 style codegen,
  				// we emit the buffer array on stack instead, and that seems to work just fine apparently.
  
  				// If the argument was marked as being in device address space, any pointer to member would
  				// be const device, not constant.
  				if (argument_buffer_device_storage_mask & (1u << desc_set))
  					decl += " const device";
  				else
  					decl += " constant";
  			}
  		}
  
  		// Special case, need to override the array size here if we're using tess level as an argument.
  		if (get_execution_model() == ExecutionModelTessellationControl && builtin &&
  		    (builtin_type == BuiltInTessLevelInner || builtin_type == BuiltInTessLevelOuter))
  		{
  			uint32_t array_size = get_physical_tess_level_array_size(builtin_type);
  			if (array_size == 1)
  			{
  				decl += " &";
  				decl += to_expression(name_id);
  			}
  			else
  			{
  				decl += " (&";
  				decl += to_expression(name_id);
  				decl += ")";
  				decl += join("[", array_size, "]");
  			}
  		}
  		else
  		{
  			auto array_size_decl = type_to_array_glsl(type);
  			if (array_size_decl.empty())
  				decl += "& ";
  			else
  				decl += " (&";
  
  			const char *restrict_kw = to_restrict(name_id);
  			if (*restrict_kw)
  			{
  				decl += " ";
  				decl += restrict_kw;
  			}
  			decl += to_expression(name_id);
  
  			if (!array_size_decl.empty())
  			{
  				decl += ")";
  				decl += array_size_decl;
  			}
  		}
  	}
  	else if (!opaque_handle && (!pull_model_inputs.count(var.basevariable) || type.basetype == SPIRType::Struct))
  	{
  		// If this is going to be a reference to a variable pointer, the address space
  		// for the reference has to go before the '&', but after the '*'.
  		if (!address_space.empty())
  		{
  			if (type_is_pointer(type))
  			{
  				if (*cv_qualifier == '\0')
  					decl += ' ';
  				decl += join(address_space, " ");
  			}
  			else
  				decl = join(address_space, " ", decl);
  		}
  		decl += "&";
  		decl += " ";
  		decl += to_restrict(name_id);
  		decl += to_expression(name_id);
  	}
  	else
  	{
  		if (!address_space.empty())
  			decl = join(address_space, " ", decl);
  		decl += " ";
  		decl += to_expression(name_id);
  	}
  
  	// Emulate texture2D atomic operations
  	auto *backing_var = maybe_get_backing_variable(name_id);
  	if (backing_var && atomic_image_vars.count(backing_var->self))
  	{
  		decl += ", device atomic_" + type_to_glsl(get<SPIRType>(var_type.image.type), 0);
  		decl += "* " + to_expression(name_id) + "_atomic";
  	}
  
  	is_using_builtin_array = false;
  
  	return decl;
  }
  
  // If we're currently in the entry point function, and the object
  // has a qualified name, use it, otherwise use the standard name.
  string CompilerMSL::to_name(uint32_t id, bool allow_alias) const
  {
  	if (current_function && (current_function->self == ir.default_entry_point))
  	{
  		auto *m = ir.find_meta(id);
  		if (m && !m->decoration.qualified_alias.empty())
  			return m->decoration.qualified_alias;
  	}
  	return Compiler::to_name(id, allow_alias);
  }
  
  // Returns a name that combines the name of the struct with the name of the member, except for Builtins
  string CompilerMSL::to_qualified_member_name(const SPIRType &type, uint32_t index)
  {
  	// Don't qualify Builtin names because they are unique and are treated as such when building expressions
  	BuiltIn builtin = BuiltInMax;
  	if (is_member_builtin(type, index, &builtin))
  		return builtin_to_glsl(builtin, type.storage);
  
  	// Strip any underscore prefix from member name
  	string mbr_name = to_member_name(type, index);
  	size_t startPos = mbr_name.find_first_not_of("_");
  	mbr_name = (startPos != string::npos) ? mbr_name.substr(startPos) : "";
  	return join(to_name(type.self), "_", mbr_name);
  }
  
  // Ensures that the specified name is permanently usable by prepending a prefix
  // if the first chars are _ and a digit, which indicate a transient name.
  string CompilerMSL::ensure_valid_name(string name, string pfx)
  {
  	return (name.size() >= 2 && name[0] == '_' && isdigit(name[1])) ? (pfx + name) : name;
  }
  
  const std::unordered_set<std::string> &CompilerMSL::get_reserved_keyword_set()
  {
  	static const unordered_set<string> keywords = {
  		"kernel",
  		"vertex",
  		"fragment",
  		"compute",
  		"bias",
  		"level",
  		"gradient2d",
  		"gradientcube",
  		"gradient3d",
  		"min_lod_clamp",
  		"assert",
  		"VARIABLE_TRACEPOINT",
  		"STATIC_DATA_TRACEPOINT",
  		"STATIC_DATA_TRACEPOINT_V",
  		"METAL_ALIGN",
  		"METAL_ASM",
  		"METAL_CONST",
  		"METAL_DEPRECATED",
  		"METAL_ENABLE_IF",
  		"METAL_FUNC",
  		"METAL_INTERNAL",
  		"METAL_NON_NULL_RETURN",
  		"METAL_NORETURN",
  		"METAL_NOTHROW",
  		"METAL_PURE",
  		"METAL_UNAVAILABLE",
  		"METAL_IMPLICIT",
  		"METAL_EXPLICIT",
  		"METAL_CONST_ARG",
  		"METAL_ARG_UNIFORM",
  		"METAL_ZERO_ARG",
  		"METAL_VALID_LOD_ARG",
  		"METAL_VALID_LEVEL_ARG",
  		"METAL_VALID_STORE_ORDER",
  		"METAL_VALID_LOAD_ORDER",
  		"METAL_VALID_COMPARE_EXCHANGE_FAILURE_ORDER",
  		"METAL_COMPATIBLE_COMPARE_EXCHANGE_ORDERS",
  		"METAL_VALID_RENDER_TARGET",
  		"is_function_constant_defined",
  		"CHAR_BIT",
  		"SCHAR_MAX",
  		"SCHAR_MIN",
  		"UCHAR_MAX",
  		"CHAR_MAX",
  		"CHAR_MIN",
  		"USHRT_MAX",
  		"SHRT_MAX",
  		"SHRT_MIN",
  		"UINT_MAX",
  		"INT_MAX",
  		"INT_MIN",
  		"FLT_DIG",
  		"FLT_MANT_DIG",
  		"FLT_MAX_10_EXP",
  		"FLT_MAX_EXP",
  		"FLT_MIN_10_EXP",
  		"FLT_MIN_EXP",
  		"FLT_RADIX",
  		"FLT_MAX",
  		"FLT_MIN",
  		"FLT_EPSILON",
  		"FP_ILOGB0",
  		"FP_ILOGBNAN",
  		"MAXFLOAT",
  		"HUGE_VALF",
  		"INFINITY",
  		"NAN",
  		"M_E_F",
  		"M_LOG2E_F",
  		"M_LOG10E_F",
  		"M_LN2_F",
  		"M_LN10_F",
  		"M_PI_F",
  		"M_PI_2_F",
  		"M_PI_4_F",
  		"M_1_PI_F",
  		"M_2_PI_F",
  		"M_2_SQRTPI_F",
  		"M_SQRT2_F",
  		"M_SQRT1_2_F",
  		"HALF_DIG",
  		"HALF_MANT_DIG",
  		"HALF_MAX_10_EXP",
  		"HALF_MAX_EXP",
  		"HALF_MIN_10_EXP",
  		"HALF_MIN_EXP",
  		"HALF_RADIX",
  		"HALF_MAX",
  		"HALF_MIN",
  		"HALF_EPSILON",
  		"MAXHALF",
  		"HUGE_VALH",
  		"M_E_H",
  		"M_LOG2E_H",
  		"M_LOG10E_H",
  		"M_LN2_H",
  		"M_LN10_H",
  		"M_PI_H",
  		"M_PI_2_H",
  		"M_PI_4_H",
  		"M_1_PI_H",
  		"M_2_PI_H",
  		"M_2_SQRTPI_H",
  		"M_SQRT2_H",
  		"M_SQRT1_2_H",
  		"DBL_DIG",
  		"DBL_MANT_DIG",
  		"DBL_MAX_10_EXP",
  		"DBL_MAX_EXP",
  		"DBL_MIN_10_EXP",
  		"DBL_MIN_EXP",
  		"DBL_RADIX",
  		"DBL_MAX",
  		"DBL_MIN",
  		"DBL_EPSILON",
  		"HUGE_VAL",
  		"M_E",
  		"M_LOG2E",
  		"M_LOG10E",
  		"M_LN2",
  		"M_LN10",
  		"M_PI",
  		"M_PI_2",
  		"M_PI_4",
  		"M_1_PI",
  		"M_2_PI",
  		"M_2_SQRTPI",
  		"M_SQRT2",
  		"M_SQRT1_2",
  		"quad_broadcast",
  	};
  
  	return keywords;
  }
  
  const std::unordered_set<std::string> &CompilerMSL::get_illegal_func_names()
  {
  	static const unordered_set<string> illegal_func_names = {
  		"main",
  		"saturate",
  		"assert",
  		"fmin3",
  		"fmax3",
  		"VARIABLE_TRACEPOINT",
  		"STATIC_DATA_TRACEPOINT",
  		"STATIC_DATA_TRACEPOINT_V",
  		"METAL_ALIGN",
  		"METAL_ASM",
  		"METAL_CONST",
  		"METAL_DEPRECATED",
  		"METAL_ENABLE_IF",
  		"METAL_FUNC",
  		"METAL_INTERNAL",
  		"METAL_NON_NULL_RETURN",
  		"METAL_NORETURN",
  		"METAL_NOTHROW",
  		"METAL_PURE",
  		"METAL_UNAVAILABLE",
  		"METAL_IMPLICIT",
  		"METAL_EXPLICIT",
  		"METAL_CONST_ARG",
  		"METAL_ARG_UNIFORM",
  		"METAL_ZERO_ARG",
  		"METAL_VALID_LOD_ARG",
  		"METAL_VALID_LEVEL_ARG",
  		"METAL_VALID_STORE_ORDER",
  		"METAL_VALID_LOAD_ORDER",
  		"METAL_VALID_COMPARE_EXCHANGE_FAILURE_ORDER",
  		"METAL_COMPATIBLE_COMPARE_EXCHANGE_ORDERS",
  		"METAL_VALID_RENDER_TARGET",
  		"is_function_constant_defined",
  		"CHAR_BIT",
  		"SCHAR_MAX",
  		"SCHAR_MIN",
  		"UCHAR_MAX",
  		"CHAR_MAX",
  		"CHAR_MIN",
  		"USHRT_MAX",
  		"SHRT_MAX",
  		"SHRT_MIN",
  		"UINT_MAX",
  		"INT_MAX",
  		"INT_MIN",
  		"FLT_DIG",
  		"FLT_MANT_DIG",
  		"FLT_MAX_10_EXP",
  		"FLT_MAX_EXP",
  		"FLT_MIN_10_EXP",
  		"FLT_MIN_EXP",
  		"FLT_RADIX",
  		"FLT_MAX",
  		"FLT_MIN",
  		"FLT_EPSILON",
  		"FP_ILOGB0",
  		"FP_ILOGBNAN",
  		"MAXFLOAT",
  		"HUGE_VALF",
  		"INFINITY",
  		"NAN",
  		"M_E_F",
  		"M_LOG2E_F",
  		"M_LOG10E_F",
  		"M_LN2_F",
  		"M_LN10_F",
  		"M_PI_F",
  		"M_PI_2_F",
  		"M_PI_4_F",
  		"M_1_PI_F",
  		"M_2_PI_F",
  		"M_2_SQRTPI_F",
  		"M_SQRT2_F",
  		"M_SQRT1_2_F",
  		"HALF_DIG",
  		"HALF_MANT_DIG",
  		"HALF_MAX_10_EXP",
  		"HALF_MAX_EXP",
  		"HALF_MIN_10_EXP",
  		"HALF_MIN_EXP",
  		"HALF_RADIX",
  		"HALF_MAX",
  		"HALF_MIN",
  		"HALF_EPSILON",
  		"MAXHALF",
  		"HUGE_VALH",
  		"M_E_H",
  		"M_LOG2E_H",
  		"M_LOG10E_H",
  		"M_LN2_H",
  		"M_LN10_H",
  		"M_PI_H",
  		"M_PI_2_H",
  		"M_PI_4_H",
  		"M_1_PI_H",
  		"M_2_PI_H",
  		"M_2_SQRTPI_H",
  		"M_SQRT2_H",
  		"M_SQRT1_2_H",
  		"DBL_DIG",
  		"DBL_MANT_DIG",
  		"DBL_MAX_10_EXP",
  		"DBL_MAX_EXP",
  		"DBL_MIN_10_EXP",
  		"DBL_MIN_EXP",
  		"DBL_RADIX",
  		"DBL_MAX",
  		"DBL_MIN",
  		"DBL_EPSILON",
  		"HUGE_VAL",
  		"M_E",
  		"M_LOG2E",
  		"M_LOG10E",
  		"M_LN2",
  		"M_LN10",
  		"M_PI",
  		"M_PI_2",
  		"M_PI_4",
  		"M_1_PI",
  		"M_2_PI",
  		"M_2_SQRTPI",
  		"M_SQRT2",
  		"M_SQRT1_2",
  	};
  
  	return illegal_func_names;
  }
  
  // Replace all names that match MSL keywords or Metal Standard Library functions.
  void CompilerMSL::replace_illegal_names()
  {
  	// FIXME: MSL and GLSL are doing two different things here.
  	// Agree on convention and remove this override.
  	auto &keywords = get_reserved_keyword_set();
  	auto &illegal_func_names = get_illegal_func_names();
  
  	ir.for_each_typed_id<SPIRVariable>([&](uint32_t self, SPIRVariable &) {
  		auto *meta = ir.find_meta(self);
  		if (!meta)
  			return;
  
  		auto &dec = meta->decoration;
  		if (keywords.find(dec.alias) != end(keywords))
  			dec.alias += "0";
  	});
  
  	ir.for_each_typed_id<SPIRFunction>([&](uint32_t self, SPIRFunction &) {
  		auto *meta = ir.find_meta(self);
  		if (!meta)
  			return;
  
  		auto &dec = meta->decoration;
  		if (illegal_func_names.find(dec.alias) != end(illegal_func_names))
  			dec.alias += "0";
  	});
  
  	ir.for_each_typed_id<SPIRType>([&](uint32_t self, SPIRType &) {
  		auto *meta = ir.find_meta(self);
  		if (!meta)
  			return;
  
  		for (auto &mbr_dec : meta->members)
  			if (keywords.find(mbr_dec.alias) != end(keywords))
  				mbr_dec.alias += "0";
  	});
  
  	CompilerGLSL::replace_illegal_names();
  }
  
  void CompilerMSL::replace_illegal_entry_point_names()
  {
  	auto &illegal_func_names = get_illegal_func_names();
  
  	// It is important to this before we fixup identifiers,
  	// since if ep_name is reserved, we will need to fix that up,
  	// and then copy alias back into entry.name after the fixup.
  	for (auto &entry : ir.entry_points)
  	{
  		// Change both the entry point name and the alias, to keep them synced.
  		string &ep_name = entry.second.name;
  		if (illegal_func_names.find(ep_name) != end(illegal_func_names))
  			ep_name += "0";
  
  		ir.meta[entry.first].decoration.alias = ep_name;
  	}
  }
  
  void CompilerMSL::sync_entry_point_aliases_and_names()
  {
  	for (auto &entry : ir.entry_points)
  		entry.second.name = ir.meta[entry.first].decoration.alias;
  }
  
  string CompilerMSL::to_member_reference(uint32_t base, const SPIRType &type, uint32_t index, bool ptr_chain)
  {
  	if (index < uint32_t(type.member_type_index_redirection.size()))
  		index = type.member_type_index_redirection[index];
  
  	auto *var = maybe_get<SPIRVariable>(base);
  	// If this is a buffer array, we have to dereference the buffer pointers.
  	// Otherwise, if this is a pointer expression, dereference it.
  
  	bool declared_as_pointer = false;
  
  	if (var)
  	{
  		// Only allow -> dereference for block types. This is so we get expressions like
  		// buffer[i]->first_member.second_member, rather than buffer[i]->first->second.
  		bool is_block = has_decoration(type.self, DecorationBlock) || has_decoration(type.self, DecorationBufferBlock);
  
  		bool is_buffer_variable =
  		    is_block && (var->storage == StorageClassUniform || var->storage == StorageClassStorageBuffer);
  		declared_as_pointer = is_buffer_variable && is_array(get<SPIRType>(var->basetype));
  	}
  
  	if (declared_as_pointer || (!ptr_chain && should_dereference(base)))
  		return join("->", to_member_name(type, index));
  	else
  		return join(".", to_member_name(type, index));
  }
  
  string CompilerMSL::to_qualifiers_glsl(uint32_t id)
  {
  	string quals;
  
  	auto *var = maybe_get<SPIRVariable>(id);
  	auto &type = expression_type(id);
  
  	if (type.storage == StorageClassWorkgroup || (var && variable_decl_is_remapped_storage(*var, StorageClassWorkgroup)))
  		quals += "threadgroup ";
  
  	return quals;
  }
  
  // The optional id parameter indicates the object whose type we are trying
  // to find the description for. It is optional. Most type descriptions do not
  // depend on a specific object's use of that type.
  string CompilerMSL::type_to_glsl(const SPIRType &type, uint32_t id)
  {
  	string type_name;
  
  	// Pointer?
  	if (type.pointer)
  	{
  		assert(type.pointer_depth > 0);
  
  		const char *restrict_kw;
  
  		auto type_address_space = get_type_address_space(type, id);
  		auto type_decl = type_to_glsl(get<SPIRType>(type.parent_type), id);
  
  		// Work around C pointer qualifier rules. If glsl_type is a pointer type as well
  		// we'll need to emit the address space to the right.
  		// We could always go this route, but it makes the code unnatural.
  		// Prefer emitting thread T *foo over T thread* foo since it's more readable,
  		// but we'll have to emit thread T * thread * T constant bar; for example.
  		if (type_is_pointer_to_pointer(type))
  			type_name = join(type_decl, " ", type_address_space, " ");
  		else
  			type_name = join(type_address_space, " ", type_decl);
  
  		switch (type.basetype)
  		{
  		case SPIRType::Image:
  		case SPIRType::SampledImage:
  		case SPIRType::Sampler:
  			// These are handles.
  			break;
  		default:
  			// Anything else can be a raw pointer.
  			type_name += "*";
  			restrict_kw = to_restrict(id);
  			if (*restrict_kw)
  			{
  				type_name += " ";
  				type_name += restrict_kw;
  			}
  			break;
  		}
  		return type_name;
  	}
  
  	switch (type.basetype)
  	{
  	case SPIRType::Struct:
  		// Need OpName lookup here to get a "sensible" name for a struct.
  		// Allow Metal to use the array<T> template to make arrays a value type
  		type_name = to_name(type.self);
  		break;
  
  	case SPIRType::Image:
  	case SPIRType::SampledImage:
  		return image_type_glsl(type, id);
  
  	case SPIRType::Sampler:
  		return sampler_type(type, id);
  
  	case SPIRType::Void:
  		return "void";
  
  	case SPIRType::AtomicCounter:
  		return "atomic_uint";
  
  	case SPIRType::ControlPointArray:
  		return join("patch_control_point<", type_to_glsl(get<SPIRType>(type.parent_type), id), ">");
  
  	case SPIRType::Interpolant:
  		return join("interpolant<", type_to_glsl(get<SPIRType>(type.parent_type), id), ", interpolation::",
  		            has_decoration(type.self, DecorationNoPerspective) ? "no_perspective" : "perspective", ">");
  
  	// Scalars
  	case SPIRType::Boolean:
  		type_name = "bool";
  		break;
  	case SPIRType::Char:
  	case SPIRType::SByte:
  		type_name = "char";
  		break;
  	case SPIRType::UByte:
  		type_name = "uchar";
  		break;
  	case SPIRType::Short:
  		type_name = "short";
  		break;
  	case SPIRType::UShort:
  		type_name = "ushort";
  		break;
  	case SPIRType::Int:
  		type_name = "int";
  		break;
  	case SPIRType::UInt:
  		type_name = "uint";
  		break;
  	case SPIRType::Int64:
  		if (!msl_options.supports_msl_version(2, 2))
  			SPIRV_CROSS_THROW("64-bit integers are only supported in MSL 2.2 and above.");
  		type_name = "long";
  		break;
  	case SPIRType::UInt64:
  		if (!msl_options.supports_msl_version(2, 2))
  			SPIRV_CROSS_THROW("64-bit integers are only supported in MSL 2.2 and above.");
  		type_name = "ulong";
  		break;
  	case SPIRType::Half:
  		type_name = "half";
  		break;
  	case SPIRType::Float:
  		type_name = "float";
  		break;
  	case SPIRType::Double:
  		type_name = "double"; // Currently unsupported
  		break;
  
  	default:
  		return "unknown_type";
  	}
  
  	// Matrix?
  	if (type.columns > 1)
  		type_name += to_string(type.columns) + "x";
  
  	// Vector or Matrix?
  	if (type.vecsize > 1)
  		type_name += to_string(type.vecsize);
  
  	if (type.array.empty() || using_builtin_array())
  	{
  		return type_name;
  	}
  	else
  	{
  		// Allow Metal to use the array<T> template to make arrays a value type
  		add_spv_func_and_recompile(SPVFuncImplUnsafeArray);
  		string res;
  		string sizes;
  
  		for (uint32_t i = 0; i < uint32_t(type.array.size()); i++)
  		{
  			res += "spvUnsafeArray<";
  			sizes += ", ";
  			sizes += to_array_size(type, i);
  			sizes += ">";
  		}
  
  		res += type_name + sizes;
  		return res;
  	}
  }
  
  string CompilerMSL::type_to_array_glsl(const SPIRType &type)
  {
  	// Allow Metal to use the array<T> template to make arrays a value type
  	switch (type.basetype)
  	{
  	case SPIRType::AtomicCounter:
  	case SPIRType::ControlPointArray:
  	{
  		return CompilerGLSL::type_to_array_glsl(type);
  	}
  	default:
  	{
  		if (using_builtin_array())
  			return CompilerGLSL::type_to_array_glsl(type);
  		else
  			return "";
  	}
  	}
  }
  
  string CompilerMSL::constant_op_expression(const SPIRConstantOp &cop)
  {
  	auto &type = get<SPIRType>(cop.basetype);
  	string op;
  
  	switch (cop.opcode)
  	{
  	case OpQuantizeToF16:
  		switch (type.vecsize)
  		{
  		case 1:
  			op = "float(half(";
  			break;
  		case 2:
  			op = "float2(half2(";
  			break;
  		case 3:
  			op = "float3(half3(";
  			break;
  		case 4:
  			op = "float4(half4(";
  			break;
  		default:
  			SPIRV_CROSS_THROW("Illegal argument to OpSpecConstantOp QuantizeToF16.");
  		}
  		return join(op, to_expression(cop.arguments[0]), "))");
  
  	default:
  		return CompilerGLSL::constant_op_expression(cop);
  	}
  }
  
  bool CompilerMSL::variable_decl_is_remapped_storage(const SPIRVariable &variable, spv::StorageClass storage) const
  {
  	if (variable.storage == storage)
  		return true;
  
  	if (storage == StorageClassWorkgroup)
  	{
  		auto model = get_execution_model();
  
  		// Specially masked IO block variable.
  		// Normally, we will never access IO blocks directly here.
  		// The only scenario which that should occur is with a masked IO block.
  		if (model == ExecutionModelTessellationControl && variable.storage == StorageClassOutput &&
  		    has_decoration(get<SPIRType>(variable.basetype).self, DecorationBlock))
  		{
  			return true;
  		}
  
  		return variable.storage == StorageClassOutput &&
  		       model == ExecutionModelTessellationControl &&
  		       is_stage_output_variable_masked(variable);
  	}
  	else if (storage == StorageClassStorageBuffer)
  	{
  		// We won't be able to catch writes to control point outputs here since variable
  		// refers to a function local pointer.
  		// This is fine, as there cannot be concurrent writers to that memory anyways,
  		// so we just ignore that case.
  
  		return (variable.storage == StorageClassOutput || variable.storage == StorageClassInput) &&
  		       !variable_storage_requires_stage_io(variable.storage) &&
  		       (variable.storage != StorageClassOutput || !is_stage_output_variable_masked(variable));
  	}
  	else
  	{
  		return false;
  	}
  }
  
  std::string CompilerMSL::variable_decl(const SPIRVariable &variable)
  {
  	bool old_is_using_builtin_array = is_using_builtin_array;
  
  	// Threadgroup arrays can't have a wrapper type.
  	if (variable_decl_is_remapped_storage(variable, StorageClassWorkgroup))
  		is_using_builtin_array = true;
  
  	std::string expr = CompilerGLSL::variable_decl(variable);
  	is_using_builtin_array = old_is_using_builtin_array;
  	return expr;
  }
  
  // GCC workaround of lambdas calling protected funcs
  std::string CompilerMSL::variable_decl(const SPIRType &type, const std::string &name, uint32_t id)
  {
  	return CompilerGLSL::variable_decl(type, name, id);
  }
  
  std::string CompilerMSL::sampler_type(const SPIRType &type, uint32_t id)
  {
  	auto *var = maybe_get<SPIRVariable>(id);
  	if (var && var->basevariable)
  	{
  		// Check against the base variable, and not a fake ID which might have been generated for this variable.
  		id = var->basevariable;
  	}
  
  	if (!type.array.empty())
  	{
  		if (!msl_options.supports_msl_version(2))
  			SPIRV_CROSS_THROW("MSL 2.0 or greater is required for arrays of samplers.");
  
  		if (type.array.size() > 1)
  			SPIRV_CROSS_THROW("Arrays of arrays of samplers are not supported in MSL.");
  
  		// Arrays of samplers in MSL must be declared with a special array<T, N> syntax ala C++11 std::array.
  		// If we have a runtime array, it could be a variable-count descriptor set binding.
  		uint32_t array_size = to_array_size_literal(type);
  		if (array_size == 0)
  			array_size = get_resource_array_size(id);
  
  		if (array_size == 0)
  			SPIRV_CROSS_THROW("Unsized array of samplers is not supported in MSL.");
  
  		auto &parent = get<SPIRType>(get_pointee_type(type).parent_type);
  		return join("array<", sampler_type(parent, id), ", ", array_size, ">");
  	}
  	else
  		return "sampler";
  }
  
  // Returns an MSL string describing the SPIR-V image type
  string CompilerMSL::image_type_glsl(const SPIRType &type, uint32_t id)
  {
  	auto *var = maybe_get<SPIRVariable>(id);
  	if (var && var->basevariable)
  	{
  		// For comparison images, check against the base variable,
  		// and not the fake ID which might have been generated for this variable.
  		id = var->basevariable;
  	}
  
  	if (!type.array.empty())
  	{
  		uint32_t major = 2, minor = 0;
  		if (msl_options.is_ios())
  		{
  			major = 1;
  			minor = 2;
  		}
  		if (!msl_options.supports_msl_version(major, minor))
  		{
  			if (msl_options.is_ios())
  				SPIRV_CROSS_THROW("MSL 1.2 or greater is required for arrays of textures.");
  			else
  				SPIRV_CROSS_THROW("MSL 2.0 or greater is required for arrays of textures.");
  		}
  
  		if (type.array.size() > 1)
  			SPIRV_CROSS_THROW("Arrays of arrays of textures are not supported in MSL.");
  
  		// Arrays of images in MSL must be declared with a special array<T, N> syntax ala C++11 std::array.
  		// If we have a runtime array, it could be a variable-count descriptor set binding.
  		uint32_t array_size = to_array_size_literal(type);
  		if (array_size == 0)
  			array_size = get_resource_array_size(id);
  
  		if (array_size == 0)
  			SPIRV_CROSS_THROW("Unsized array of images is not supported in MSL.");
  
  		auto &parent = get<SPIRType>(get_pointee_type(type).parent_type);
  		return join("array<", image_type_glsl(parent, id), ", ", array_size, ">");
  	}
  
  	string img_type_name;
  
  	// Bypass pointers because we need the real image struct
  	auto &img_type = get<SPIRType>(type.self).image;
  	if (image_is_comparison(type, id))
  	{
  		switch (img_type.dim)
  		{
  		case Dim1D:
  		case Dim2D:
  			if (img_type.dim == Dim1D && !msl_options.texture_1D_as_2D)
  			{
  				// Use a native Metal 1D texture
  				img_type_name += "depth1d_unsupported_by_metal";
  				break;
  			}
  
  			if (img_type.ms && img_type.arrayed)
  			{
  				if (!msl_options.supports_msl_version(2, 1))
  					SPIRV_CROSS_THROW("Multisampled array textures are supported from 2.1.");
  				img_type_name += "depth2d_ms_array";
  			}
  			else if (img_type.ms)
  				img_type_name += "depth2d_ms";
  			else if (img_type.arrayed)
  				img_type_name += "depth2d_array";
  			else
  				img_type_name += "depth2d";
  			break;
  		case Dim3D:
  			img_type_name += "depth3d_unsupported_by_metal";
  			break;
  		case DimCube:
  			if (!msl_options.emulate_cube_array)
  				img_type_name += (img_type.arrayed ? "depthcube_array" : "depthcube");
  			else
  				img_type_name += (img_type.arrayed ? "depth2d_array" : "depthcube");
  			break;
  		default:
  			img_type_name += "unknown_depth_texture_type";
  			break;
  		}
  	}
  	else
  	{
  		switch (img_type.dim)
  		{
  		case DimBuffer:
  			if (img_type.ms || img_type.arrayed)
  				SPIRV_CROSS_THROW("Cannot use texel buffers with multisampling or array layers.");
  
  			if (msl_options.texture_buffer_native)
  			{
  				if (!msl_options.supports_msl_version(2, 1))
  					SPIRV_CROSS_THROW("Native texture_buffer type is only supported in MSL 2.1.");
  				img_type_name = "texture_buffer";
  			}
  			else
  				img_type_name += "texture2d";
  			break;
  		case Dim1D:
  		case Dim2D:
  		case DimSubpassData:
  		{
  			bool subpass_array =
  			    img_type.dim == DimSubpassData && (msl_options.multiview || msl_options.arrayed_subpass_input);
  			if (img_type.dim == Dim1D && !msl_options.texture_1D_as_2D)
  			{
  				// Use a native Metal 1D texture
  				img_type_name += (img_type.arrayed ? "texture1d_array" : "texture1d");
  				break;
  			}
  
  			// Use Metal's native frame-buffer fetch API for subpass inputs.
  			if (type_is_msl_framebuffer_fetch(type))
  			{
  				auto img_type_4 = get<SPIRType>(img_type.type);
  				img_type_4.vecsize = 4;
  				return type_to_glsl(img_type_4);
  			}
  			if (img_type.ms && (img_type.arrayed || subpass_array))
  			{
  				if (!msl_options.supports_msl_version(2, 1))
  					SPIRV_CROSS_THROW("Multisampled array textures are supported from 2.1.");
  				img_type_name += "texture2d_ms_array";
  			}
  			else if (img_type.ms)
  				img_type_name += "texture2d_ms";
  			else if (img_type.arrayed || subpass_array)
  				img_type_name += "texture2d_array";
  			else
  				img_type_name += "texture2d";
  			break;
  		}
  		case Dim3D:
  			img_type_name += "texture3d";
  			break;
  		case DimCube:
  			if (!msl_options.emulate_cube_array)
  				img_type_name += (img_type.arrayed ? "texturecube_array" : "texturecube");
  			else
  				img_type_name += (img_type.arrayed ? "texture2d_array" : "texturecube");
  			break;
  		default:
  			img_type_name += "unknown_texture_type";
  			break;
  		}
  	}
  
  	// Append the pixel type
  	img_type_name += "<";
  	img_type_name += type_to_glsl(get<SPIRType>(img_type.type));
  
  	// For unsampled images, append the sample/read/write access qualifier.
  	// For kernel images, the access qualifier my be supplied directly by SPIR-V.
  	// Otherwise it may be set based on whether the image is read from or written to within the shader.
  	if (type.basetype == SPIRType::Image && type.image.sampled == 2 && type.image.dim != DimSubpassData)
  	{
  		switch (img_type.access)
  		{
  		case AccessQualifierReadOnly:
  			img_type_name += ", access::read";
  			break;
  
  		case AccessQualifierWriteOnly:
  			img_type_name += ", access::write";
  			break;
  
  		case AccessQualifierReadWrite:
  			img_type_name += ", access::read_write";
  			break;
  
  		default:
  		{
  			auto *p_var = maybe_get_backing_variable(id);
  			if (p_var && p_var->basevariable)
  				p_var = maybe_get<SPIRVariable>(p_var->basevariable);
  			if (p_var && !has_decoration(p_var->self, DecorationNonWritable))
  			{
  				img_type_name += ", access::";
  
  				if (!has_decoration(p_var->self, DecorationNonReadable))
  					img_type_name += "read_";
  
  				img_type_name += "write";
  			}
  			break;
  		}
  		}
  	}
  
  	img_type_name += ">";
  
  	return img_type_name;
  }
  
  void CompilerMSL::emit_subgroup_op(const Instruction &i)
  {
  	const uint32_t *ops = stream(i);
  	auto op = static_cast<Op>(i.op);
  
  	if (msl_options.emulate_subgroups)
  	{
  		// In this mode, only the GroupNonUniform cap is supported. The only op
  		// we need to handle, then, is OpGroupNonUniformElect.
  		if (op != OpGroupNonUniformElect)
  			SPIRV_CROSS_THROW("Subgroup emulation does not support operations other than Elect.");
  		// In this mode, the subgroup size is assumed to be one, so every invocation
  		// is elected.
  		emit_op(ops[0], ops[1], "true", true);
  		return;
  	}
  
  	// Metal 2.0 is required. iOS only supports quad ops on 11.0 (2.0), with
  	// full support in 13.0 (2.2). macOS only supports broadcast and shuffle on
  	// 10.13 (2.0), with full support in 10.14 (2.1).
  	// Note that Apple GPUs before A13 make no distinction between a quad-group
  	// and a SIMD-group; all SIMD-groups are quad-groups on those.
  	if (!msl_options.supports_msl_version(2))
  		SPIRV_CROSS_THROW("Subgroups are only supported in Metal 2.0 and up.");
  
  	// If we need to do implicit bitcasts, make sure we do it with the correct type.
  	uint32_t integer_width = get_integer_width_for_instruction(i);
  	auto int_type = to_signed_basetype(integer_width);
  	auto uint_type = to_unsigned_basetype(integer_width);
  
  	if (msl_options.is_ios() && (!msl_options.supports_msl_version(2, 3) || !msl_options.ios_use_simdgroup_functions))
  	{
  		switch (op)
  		{
  		default:
  			SPIRV_CROSS_THROW("Subgroup ops beyond broadcast, ballot, and shuffle on iOS require Metal 2.3 and up.");
  		case OpGroupNonUniformBroadcastFirst:
  			if (!msl_options.supports_msl_version(2, 2))
  				SPIRV_CROSS_THROW("BroadcastFirst on iOS requires Metal 2.2 and up.");
  			break;
  		case OpGroupNonUniformElect:
  			if (!msl_options.supports_msl_version(2, 2))
  				SPIRV_CROSS_THROW("Elect on iOS requires Metal 2.2 and up.");
  			break;
  		case OpGroupNonUniformAny:
  		case OpGroupNonUniformAll:
  		case OpGroupNonUniformAllEqual:
  		case OpGroupNonUniformBallot:
  		case OpGroupNonUniformInverseBallot:
  		case OpGroupNonUniformBallotBitExtract:
  		case OpGroupNonUniformBallotFindLSB:
  		case OpGroupNonUniformBallotFindMSB:
  		case OpGroupNonUniformBallotBitCount:
  			if (!msl_options.supports_msl_version(2, 2))
  				SPIRV_CROSS_THROW("Ballot ops on iOS requires Metal 2.2 and up.");
  			break;
  		case OpGroupNonUniformBroadcast:
  		case OpGroupNonUniformShuffle:
  		case OpGroupNonUniformShuffleXor:
  		case OpGroupNonUniformShuffleUp:
  		case OpGroupNonUniformShuffleDown:
  		case OpGroupNonUniformQuadSwap:
  		case OpGroupNonUniformQuadBroadcast:
  			break;
  		}
  	}
  
  	if (msl_options.is_macos() && !msl_options.supports_msl_version(2, 1))
  	{
  		switch (op)
  		{
  		default:
  			SPIRV_CROSS_THROW("Subgroup ops beyond broadcast and shuffle on macOS require Metal 2.1 and up.");
  		case OpGroupNonUniformBroadcast:
  		case OpGroupNonUniformShuffle:
  		case OpGroupNonUniformShuffleXor:
  		case OpGroupNonUniformShuffleUp:
  		case OpGroupNonUniformShuffleDown:
  			break;
  		}
  	}
  
  	uint32_t result_type = ops[0];
  	uint32_t id = ops[1];
  
  	auto scope = static_cast<Scope>(evaluate_constant_u32(ops[2]));
  	if (scope != ScopeSubgroup)
  		SPIRV_CROSS_THROW("Only subgroup scope is supported.");
  
  	switch (op)
  	{
  	case OpGroupNonUniformElect:
  		if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  			emit_op(result_type, id, "quad_is_first()", false);
  		else
  			emit_op(result_type, id, "simd_is_first()", false);
  		break;
  
  	case OpGroupNonUniformBroadcast:
  		emit_binary_func_op(result_type, id, ops[3], ops[4], "spvSubgroupBroadcast");
  		break;
  
  	case OpGroupNonUniformBroadcastFirst:
  		emit_unary_func_op(result_type, id, ops[3], "spvSubgroupBroadcastFirst");
  		break;
  
  	case OpGroupNonUniformBallot:
  		emit_unary_func_op(result_type, id, ops[3], "spvSubgroupBallot");
  		break;
  
  	case OpGroupNonUniformInverseBallot:
  		emit_binary_func_op(result_type, id, ops[3], builtin_subgroup_invocation_id_id, "spvSubgroupBallotBitExtract");
  		break;
  
  	case OpGroupNonUniformBallotBitExtract:
  		emit_binary_func_op(result_type, id, ops[3], ops[4], "spvSubgroupBallotBitExtract");
  		break;
  
  	case OpGroupNonUniformBallotFindLSB:
  		emit_binary_func_op(result_type, id, ops[3], builtin_subgroup_size_id, "spvSubgroupBallotFindLSB");
  		break;
  
  	case OpGroupNonUniformBallotFindMSB:
  		emit_binary_func_op(result_type, id, ops[3], builtin_subgroup_size_id, "spvSubgroupBallotFindMSB");
  		break;
  
  	case OpGroupNonUniformBallotBitCount:
  	{
  		auto operation = static_cast<GroupOperation>(ops[3]);
  		switch (operation)
  		{
  		case GroupOperationReduce:
  			emit_binary_func_op(result_type, id, ops[4], builtin_subgroup_size_id, "spvSubgroupBallotBitCount");
  			break;
  		case GroupOperationInclusiveScan:
  			emit_binary_func_op(result_type, id, ops[4], builtin_subgroup_invocation_id_id,
  			                    "spvSubgroupBallotInclusiveBitCount");
  			break;
  		case GroupOperationExclusiveScan:
  			emit_binary_func_op(result_type, id, ops[4], builtin_subgroup_invocation_id_id,
  			                    "spvSubgroupBallotExclusiveBitCount");
  			break;
  		default:
  			SPIRV_CROSS_THROW("Invalid BitCount operation.");
  		}
  		break;
  	}
  
  	case OpGroupNonUniformShuffle:
  		emit_binary_func_op(result_type, id, ops[3], ops[4], "spvSubgroupShuffle");
  		break;
  
  	case OpGroupNonUniformShuffleXor:
  		emit_binary_func_op(result_type, id, ops[3], ops[4], "spvSubgroupShuffleXor");
  		break;
  
  	case OpGroupNonUniformShuffleUp:
  		emit_binary_func_op(result_type, id, ops[3], ops[4], "spvSubgroupShuffleUp");
  		break;
  
  	case OpGroupNonUniformShuffleDown:
  		emit_binary_func_op(result_type, id, ops[3], ops[4], "spvSubgroupShuffleDown");
  		break;
  
  	case OpGroupNonUniformAll:
  		if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  			emit_unary_func_op(result_type, id, ops[3], "quad_all");
  		else
  			emit_unary_func_op(result_type, id, ops[3], "simd_all");
  		break;
  
  	case OpGroupNonUniformAny:
  		if (msl_options.is_ios() && !msl_options.ios_use_simdgroup_functions)
  			emit_unary_func_op(result_type, id, ops[3], "quad_any");
  		else
  			emit_unary_func_op(result_type, id, ops[3], "simd_any");
  		break;
  
  	case OpGroupNonUniformAllEqual:
  		emit_unary_func_op(result_type, id, ops[3], "spvSubgroupAllEqual");
  		break;
  
  		// clang-format off
  #define MSL_GROUP_OP(op, msl_op) \
  case OpGroupNonUniform##op: \
  	{ \
  		auto operation = static_cast<GroupOperation>(ops[3]); \
  		if (operation == GroupOperationReduce) \
  			emit_unary_func_op(result_type, id, ops[4], "simd_" #msl_op); \
  		else if (operation == GroupOperationInclusiveScan) \
  			emit_unary_func_op(result_type, id, ops[4], "simd_prefix_inclusive_" #msl_op); \
  		else if (operation == GroupOperationExclusiveScan) \
  			emit_unary_func_op(result_type, id, ops[4], "simd_prefix_exclusive_" #msl_op); \
  		else if (operation == GroupOperationClusteredReduce) \
  		{ \
  			/* Only cluster sizes of 4 are supported. */ \
  			uint32_t cluster_size = evaluate_constant_u32(ops[5]); \
  			if (cluster_size != 4) \
  				SPIRV_CROSS_THROW("Metal only supports quad ClusteredReduce."); \
  			emit_unary_func_op(result_type, id, ops[4], "quad_" #msl_op); \
  		} \
  		else \
  			SPIRV_CROSS_THROW("Invalid group operation."); \
  		break; \
  	}
  	MSL_GROUP_OP(FAdd, sum)
  	MSL_GROUP_OP(FMul, product)
  	MSL_GROUP_OP(IAdd, sum)
  	MSL_GROUP_OP(IMul, product)
  #undef MSL_GROUP_OP
  	// The others, unfortunately, don't support InclusiveScan or ExclusiveScan.
  
  #define MSL_GROUP_OP(op, msl_op) \
  case OpGroupNonUniform##op: \
  	{ \
  		auto operation = static_cast<GroupOperation>(ops[3]); \
  		if (operation == GroupOperationReduce) \
  			emit_unary_func_op(result_type, id, ops[4], "simd_" #msl_op); \
  		else if (operation == GroupOperationInclusiveScan) \
  			SPIRV_CROSS_THROW("Metal doesn't support InclusiveScan for OpGroupNonUniform" #op "."); \
  		else if (operation == GroupOperationExclusiveScan) \
  			SPIRV_CROSS_THROW("Metal doesn't support ExclusiveScan for OpGroupNonUniform" #op "."); \
  		else if (operation == GroupOperationClusteredReduce) \
  		{ \
  			/* Only cluster sizes of 4 are supported. */ \
  			uint32_t cluster_size = evaluate_constant_u32(ops[5]); \
  			if (cluster_size != 4) \
  				SPIRV_CROSS_THROW("Metal only supports quad ClusteredReduce."); \
  			emit_unary_func_op(result_type, id, ops[4], "quad_" #msl_op); \
  		} \
  		else \
  			SPIRV_CROSS_THROW("Invalid group operation."); \
  		break; \
  	}
  
  #define MSL_GROUP_OP_CAST(op, msl_op, type) \
  case OpGroupNonUniform##op: \
  	{ \
  		auto operation = static_cast<GroupOperation>(ops[3]); \
  		if (operation == GroupOperationReduce) \
  			emit_unary_func_op_cast(result_type, id, ops[4], "simd_" #msl_op, type, type); \
  		else if (operation == GroupOperationInclusiveScan) \
  			SPIRV_CROSS_THROW("Metal doesn't support InclusiveScan for OpGroupNonUniform" #op "."); \
  		else if (operation == GroupOperationExclusiveScan) \
  			SPIRV_CROSS_THROW("Metal doesn't support ExclusiveScan for OpGroupNonUniform" #op "."); \
  		else if (operation == GroupOperationClusteredReduce) \
  		{ \
  			/* Only cluster sizes of 4 are supported. */ \
  			uint32_t cluster_size = evaluate_constant_u32(ops[5]); \
  			if (cluster_size != 4) \
  				SPIRV_CROSS_THROW("Metal only supports quad ClusteredReduce."); \
  			emit_unary_func_op_cast(result_type, id, ops[4], "quad_" #msl_op, type, type); \
  		} \
  		else \
  			SPIRV_CROSS_THROW("Invalid group operation."); \
  		break; \
  	}
  
  	MSL_GROUP_OP(FMin, min)
  	MSL_GROUP_OP(FMax, max)
  	MSL_GROUP_OP_CAST(SMin, min, int_type)
  	MSL_GROUP_OP_CAST(SMax, max, int_type)
  	MSL_GROUP_OP_CAST(UMin, min, uint_type)
  	MSL_GROUP_OP_CAST(UMax, max, uint_type)
  	MSL_GROUP_OP(BitwiseAnd, and)
  	MSL_GROUP_OP(BitwiseOr, or)
  	MSL_GROUP_OP(BitwiseXor, xor)
  	MSL_GROUP_OP(LogicalAnd, and)
  	MSL_GROUP_OP(LogicalOr, or)
  	MSL_GROUP_OP(LogicalXor, xor)
  		// clang-format on
  #undef MSL_GROUP_OP
  #undef MSL_GROUP_OP_CAST
  
  	case OpGroupNonUniformQuadSwap:
  		emit_binary_func_op(result_type, id, ops[3], ops[4], "spvQuadSwap");
  		break;
  
  	case OpGroupNonUniformQuadBroadcast:
  		emit_binary_func_op(result_type, id, ops[3], ops[4], "spvQuadBroadcast");
  		break;
  
  	default:
  		SPIRV_CROSS_THROW("Invalid opcode for subgroup.");
  	}
  
  	register_control_dependent_expression(id);
  }
  
  string CompilerMSL::bitcast_glsl_op(const SPIRType &out_type, const SPIRType &in_type)
  {
  	if (out_type.basetype == in_type.basetype)
  		return "";
  
  	assert(out_type.basetype != SPIRType::Boolean);
  	assert(in_type.basetype != SPIRType::Boolean);
  
  	bool integral_cast = type_is_integral(out_type) && type_is_integral(in_type) && (out_type.vecsize == in_type.vecsize);
  	bool same_size_cast = (out_type.width * out_type.vecsize) == (in_type.width * in_type.vecsize);
  
  	// Bitcasting can only be used between types of the same overall size.
  	// And always formally cast between integers, because it's trivial, and also
  	// because Metal can internally cast the results of some integer ops to a larger
  	// size (eg. short shift right becomes int), which means chaining integer ops
  	// together may introduce size variations that SPIR-V doesn't know about.
  	if (same_size_cast && !integral_cast)
  	{
  		return "as_type<" + type_to_glsl(out_type) + ">";
  	}
  	else
  	{
  		return type_to_glsl(out_type);
  	}
  }
  
  bool CompilerMSL::emit_complex_bitcast(uint32_t, uint32_t, uint32_t)
  {
  	return false;
  }
  
  // Returns an MSL string identifying the name of a SPIR-V builtin.
  // Output builtins are qualified with the name of the stage out structure.
  string CompilerMSL::builtin_to_glsl(BuiltIn builtin, StorageClass storage)
  {
  	switch (builtin)
  	{
  	// Handle HLSL-style 0-based vertex/instance index.
  	// Override GLSL compiler strictness
  	case BuiltInVertexId:
  		ensure_builtin(StorageClassInput, BuiltInVertexId);
  		if (msl_options.enable_base_index_zero && msl_options.supports_msl_version(1, 1) &&
  		    (msl_options.ios_support_base_vertex_instance || msl_options.is_macos()))
  		{
  			if (builtin_declaration)
  			{
  				if (needs_base_vertex_arg != TriState::No)
  					needs_base_vertex_arg = TriState::Yes;
  				return "gl_VertexID";
  			}
  			else
  			{
  				ensure_builtin(StorageClassInput, BuiltInBaseVertex);
  				return "(gl_VertexID - gl_BaseVertex)";
  			}
  		}
  		else
  		{
  			return "gl_VertexID";
  		}
  	case BuiltInInstanceId:
  		ensure_builtin(StorageClassInput, BuiltInInstanceId);
  		if (msl_options.enable_base_index_zero && msl_options.supports_msl_version(1, 1) &&
  		    (msl_options.ios_support_base_vertex_instance || msl_options.is_macos()))
  		{
  			if (builtin_declaration)
  			{
  				if (needs_base_instance_arg != TriState::No)
  					needs_base_instance_arg = TriState::Yes;
  				return "gl_InstanceID";
  			}
  			else
  			{
  				ensure_builtin(StorageClassInput, BuiltInBaseInstance);
  				return "(gl_InstanceID - gl_BaseInstance)";
  			}
  		}
  		else
  		{
  			return "gl_InstanceID";
  		}
  	case BuiltInVertexIndex:
  		ensure_builtin(StorageClassInput, BuiltInVertexIndex);
  		if (msl_options.enable_base_index_zero && msl_options.supports_msl_version(1, 1) &&
  		    (msl_options.ios_support_base_vertex_instance || msl_options.is_macos()))
  		{
  			if (builtin_declaration)
  			{
  				if (needs_base_vertex_arg != TriState::No)
  					needs_base_vertex_arg = TriState::Yes;
  				return "gl_VertexIndex";
  			}
  			else
  			{
  				ensure_builtin(StorageClassInput, BuiltInBaseVertex);
  				return "(gl_VertexIndex - gl_BaseVertex)";
  			}
  		}
  		else
  		{
  			return "gl_VertexIndex";
  		}
  	case BuiltInInstanceIndex:
  		ensure_builtin(StorageClassInput, BuiltInInstanceIndex);
  		if (msl_options.enable_base_index_zero && msl_options.supports_msl_version(1, 1) &&
  		    (msl_options.ios_support_base_vertex_instance || msl_options.is_macos()))
  		{
  			if (builtin_declaration)
  			{
  				if (needs_base_instance_arg != TriState::No)
  					needs_base_instance_arg = TriState::Yes;
  				return "gl_InstanceIndex";
  			}
  			else
  			{
  				ensure_builtin(StorageClassInput, BuiltInBaseInstance);
  				return "(gl_InstanceIndex - gl_BaseInstance)";
  			}
  		}
  		else
  		{
  			return "gl_InstanceIndex";
  		}
  	case BuiltInBaseVertex:
  		if (msl_options.supports_msl_version(1, 1) &&
  		    (msl_options.ios_support_base_vertex_instance || msl_options.is_macos()))
  		{
  			needs_base_vertex_arg = TriState::No;
  			return "gl_BaseVertex";
  		}
  		else
  		{
  			SPIRV_CROSS_THROW("BaseVertex requires Metal 1.1 and Mac or Apple A9+ hardware.");
  		}
  	case BuiltInBaseInstance:
  		if (msl_options.supports_msl_version(1, 1) &&
  		    (msl_options.ios_support_base_vertex_instance || msl_options.is_macos()))
  		{
  			needs_base_instance_arg = TriState::No;
  			return "gl_BaseInstance";
  		}
  		else
  		{
  			SPIRV_CROSS_THROW("BaseInstance requires Metal 1.1 and Mac or Apple A9+ hardware.");
  		}
  	case BuiltInDrawIndex:
  		SPIRV_CROSS_THROW("DrawIndex is not supported in MSL.");
  
  	// When used in the entry function, output builtins are qualified with output struct name.
  	// Test storage class as NOT Input, as output builtins might be part of generic type.
  	// Also don't do this for tessellation control shaders.
  	case BuiltInViewportIndex:
  		if (!msl_options.supports_msl_version(2, 0))
  			SPIRV_CROSS_THROW("ViewportIndex requires Metal 2.0.");
  		/* fallthrough */
  	case BuiltInFragDepth:
  	case BuiltInFragStencilRefEXT:
  		if ((builtin == BuiltInFragDepth && !msl_options.enable_frag_depth_builtin) ||
  		    (builtin == BuiltInFragStencilRefEXT && !msl_options.enable_frag_stencil_ref_builtin))
  			break;
  		/* fallthrough */
  	case BuiltInPosition:
  	case BuiltInPointSize:
  	case BuiltInClipDistance:
  	case BuiltInCullDistance:
  	case BuiltInLayer:
  		if (get_execution_model() == ExecutionModelTessellationControl)
  			break;
  		if (storage != StorageClassInput && current_function && (current_function->self == ir.default_entry_point) &&
  		    !is_stage_output_builtin_masked(builtin))
  			return stage_out_var_name + "." + CompilerGLSL::builtin_to_glsl(builtin, storage);
  		break;
  
  	case BuiltInSampleMask:
  		if (storage == StorageClassInput && current_function && (current_function->self == ir.default_entry_point) &&
  			(has_additional_fixed_sample_mask() || needs_sample_id))
  		{
  			string samp_mask_in;
  			samp_mask_in += "(" + CompilerGLSL::builtin_to_glsl(builtin, storage);
  			if (has_additional_fixed_sample_mask())
  				samp_mask_in += " & " + additional_fixed_sample_mask_str();
  			if (needs_sample_id)
  				samp_mask_in += " & (1 << gl_SampleID)";
  			samp_mask_in += ")";
  			return samp_mask_in;
  		}
  		if (storage != StorageClassInput && current_function && (current_function->self == ir.default_entry_point) &&
  		    !is_stage_output_builtin_masked(builtin))
  			return stage_out_var_name + "." + CompilerGLSL::builtin_to_glsl(builtin, storage);
  		break;
  
  	case BuiltInBaryCoordNV:
  	case BuiltInBaryCoordNoPerspNV:
  		if (storage == StorageClassInput && current_function && (current_function->self == ir.default_entry_point))
  			return stage_in_var_name + "." + CompilerGLSL::builtin_to_glsl(builtin, storage);
  		break;
  
  	case BuiltInTessLevelOuter:
  		if (get_execution_model() == ExecutionModelTessellationControl &&
  		    storage != StorageClassInput && current_function && (current_function->self == ir.default_entry_point))
  		{
  			return join(tess_factor_buffer_var_name, "[", to_expression(builtin_primitive_id_id),
  			            "].edgeTessellationFactor");
  		}
  		break;
  
  	case BuiltInTessLevelInner:
  		if (get_execution_model() == ExecutionModelTessellationControl &&
  		    storage != StorageClassInput && current_function && (current_function->self == ir.default_entry_point))
  		{
  			return join(tess_factor_buffer_var_name, "[", to_expression(builtin_primitive_id_id),
  			            "].insideTessellationFactor");
  		}
  		break;
  
  	default:
  		break;
  	}
  
  	return CompilerGLSL::builtin_to_glsl(builtin, storage);
  }
  
  // Returns an MSL string attribute qualifer for a SPIR-V builtin
  string CompilerMSL::builtin_qualifier(BuiltIn builtin)
  {
  	auto &execution = get_entry_point();
  
  	switch (builtin)
  	{
  	// Vertex function in
  	case BuiltInVertexId:
  		return "vertex_id";
  	case BuiltInVertexIndex:
  		return "vertex_id";
  	case BuiltInBaseVertex:
  		return "base_vertex";
  	case BuiltInInstanceId:
  		return "instance_id";
  	case BuiltInInstanceIndex:
  		return "instance_id";
  	case BuiltInBaseInstance:
  		return "base_instance";
  	case BuiltInDrawIndex:
  		SPIRV_CROSS_THROW("DrawIndex is not supported in MSL.");
  
  	// Vertex function out
  	case BuiltInClipDistance:
  		return "clip_distance";
  	case BuiltInPointSize:
  		return "point_size";
  	case BuiltInPosition:
  		if (position_invariant)
  		{
  			if (!msl_options.supports_msl_version(2, 1))
  				SPIRV_CROSS_THROW("Invariant position is only supported on MSL 2.1 and up.");
  			return "position, invariant";
  		}
  		else
  			return "position";
  	case BuiltInLayer:
  		return "render_target_array_index";
  	case BuiltInViewportIndex:
  		if (!msl_options.supports_msl_version(2, 0))
  			SPIRV_CROSS_THROW("ViewportIndex requires Metal 2.0.");
  		return "viewport_array_index";
  
  	// Tess. control function in
  	case BuiltInInvocationId:
  		if (msl_options.multi_patch_workgroup)
  		{
  			// Shouldn't be reached.
  			SPIRV_CROSS_THROW("InvocationId is computed manually with multi-patch workgroups in MSL.");
  		}
  		return "thread_index_in_threadgroup";
  	case BuiltInPatchVertices:
  		// Shouldn't be reached.
  		SPIRV_CROSS_THROW("PatchVertices is derived from the auxiliary buffer in MSL.");
  	case BuiltInPrimitiveId:
  		switch (execution.model)
  		{
  		case ExecutionModelTessellationControl:
  			if (msl_options.multi_patch_workgroup)
  			{
  				// Shouldn't be reached.
  				SPIRV_CROSS_THROW("PrimitiveId is computed manually with multi-patch workgroups in MSL.");
  			}
  			return "threadgroup_position_in_grid";
  		case ExecutionModelTessellationEvaluation:
  			return "patch_id";
  		case ExecutionModelFragment:
  			if (msl_options.is_ios() && !msl_options.supports_msl_version(2, 3))
  				SPIRV_CROSS_THROW("PrimitiveId on iOS requires MSL 2.3.");
  			else if (msl_options.is_macos() && !msl_options.supports_msl_version(2, 2))
  				SPIRV_CROSS_THROW("PrimitiveId on macOS requires MSL 2.2.");
  			return "primitive_id";
  		default:
  			SPIRV_CROSS_THROW("PrimitiveId is not supported in this execution model.");
  		}
  
  	// Tess. control function out
  	case BuiltInTessLevelOuter:
  	case BuiltInTessLevelInner:
  		// Shouldn't be reached.
  		SPIRV_CROSS_THROW("Tessellation levels are handled specially in MSL.");
  
  	// Tess. evaluation function in
  	case BuiltInTessCoord:
  		return "position_in_patch";
  
  	// Fragment function in
  	case BuiltInFrontFacing:
  		return "front_facing";
  	case BuiltInPointCoord:
  		return "point_coord";
  	case BuiltInFragCoord:
  		return "position";
  	case BuiltInSampleId:
  		return "sample_id";
  	case BuiltInSampleMask:
  		return "sample_mask";
  	case BuiltInSamplePosition:
  		// Shouldn't be reached.
  		SPIRV_CROSS_THROW("Sample position is retrieved by a function in MSL.");
  	case BuiltInViewIndex:
  		if (execution.model != ExecutionModelFragment)
  			SPIRV_CROSS_THROW("ViewIndex is handled specially outside fragment shaders.");
  		// The ViewIndex was implicitly used in the prior stages to set the render_target_array_index,
  		// so we can get it from there.
  		return "render_target_array_index";
  
  	// Fragment function out
  	case BuiltInFragDepth:
  		if (execution.flags.get(ExecutionModeDepthGreater))
  			return "depth(greater)";
  		else if (execution.flags.get(ExecutionModeDepthLess))
  			return "depth(less)";
  		else
  			return "depth(any)";
  
  	case BuiltInFragStencilRefEXT:
  		return "stencil";
  
  	// Compute function in
  	case BuiltInGlobalInvocationId:
  		return "thread_position_in_grid";
  
  	case BuiltInWorkgroupId:
  		return "threadgroup_position_in_grid";
  
  	case BuiltInNumWorkgroups:
  		return "threadgroups_per_grid";
  
  	case BuiltInLocalInvocationId:
  		return "thread_position_in_threadgroup";
  
  	case BuiltInLocalInvocationIndex:
  		return "thread_index_in_threadgroup";
  
  	case BuiltInSubgroupSize:
  		if (msl_options.emulate_subgroups || msl_options.fixed_subgroup_size != 0)
  			// Shouldn't be reached.
  			SPIRV_CROSS_THROW("Emitting threads_per_simdgroup attribute with fixed subgroup size??");
  		if (execution.model == ExecutionModelFragment)
  		{
  			if (!msl_options.supports_msl_version(2, 2))
  				SPIRV_CROSS_THROW("threads_per_simdgroup requires Metal 2.2 in fragment shaders.");
  			return "threads_per_simdgroup";
  		}
  		else
  		{
  			// thread_execution_width is an alias for threads_per_simdgroup, and it's only available since 1.0,
  			// but not in fragment.
  			return "thread_execution_width";
  		}
  
  	case BuiltInNumSubgroups:
  		if (msl_options.emulate_subgroups)
  			// Shouldn't be reached.
  			SPIRV_CROSS_THROW("NumSubgroups is handled specially with emulation.");
  		if (!msl_options.supports_msl_version(2))
  			SPIRV_CROSS_THROW("Subgroup builtins require Metal 2.0.");
  		return msl_options.is_ios() ? "quadgroups_per_threadgroup" : "simdgroups_per_threadgroup";
  
  	case BuiltInSubgroupId:
  		if (msl_options.emulate_subgroups)
  			// Shouldn't be reached.
  			SPIRV_CROSS_THROW("SubgroupId is handled specially with emulation.");
  		if (!msl_options.supports_msl_version(2))
  			SPIRV_CROSS_THROW("Subgroup builtins require Metal 2.0.");
  		return msl_options.is_ios() ? "quadgroup_index_in_threadgroup" : "simdgroup_index_in_threadgroup";
  
  	case BuiltInSubgroupLocalInvocationId:
  		if (msl_options.emulate_subgroups)
  			// Shouldn't be reached.
  			SPIRV_CROSS_THROW("SubgroupLocalInvocationId is handled specially with emulation.");
  		if (execution.model == ExecutionModelFragment)
  		{
  			if (!msl_options.supports_msl_version(2, 2))
  				SPIRV_CROSS_THROW("thread_index_in_simdgroup requires Metal 2.2 in fragment shaders.");
  			return "thread_index_in_simdgroup";
  		}
  		else if (execution.model == ExecutionModelKernel || execution.model == ExecutionModelGLCompute ||
  		         execution.model == ExecutionModelTessellationControl ||
  		         (execution.model == ExecutionModelVertex && msl_options.vertex_for_tessellation))
  		{
  			// We are generating a Metal kernel function.
  			if (!msl_options.supports_msl_version(2))
  				SPIRV_CROSS_THROW("Subgroup builtins in kernel functions require Metal 2.0.");
  			return msl_options.is_ios() ? "thread_index_in_quadgroup" : "thread_index_in_simdgroup";
  		}
  		else
  			SPIRV_CROSS_THROW("Subgroup builtins are not available in this type of function.");
  
  	case BuiltInSubgroupEqMask:
  	case BuiltInSubgroupGeMask:
  	case BuiltInSubgroupGtMask:
  	case BuiltInSubgroupLeMask:
  	case BuiltInSubgroupLtMask:
  		// Shouldn't be reached.
  		SPIRV_CROSS_THROW("Subgroup ballot masks are handled specially in MSL.");
  
  	case BuiltInBaryCoordNV:
  		// TODO: AMD barycentrics as well? Seem to have different swizzle and 2 components rather than 3.
  		if (msl_options.is_ios() && !msl_options.supports_msl_version(2, 3))
  			SPIRV_CROSS_THROW("Barycentrics are only supported in MSL 2.3 and above on iOS.");
  		else if (!msl_options.supports_msl_version(2, 2))
  			SPIRV_CROSS_THROW("Barycentrics are only supported in MSL 2.2 and above on macOS.");
  		return "barycentric_coord, center_perspective";
  
  	case BuiltInBaryCoordNoPerspNV:
  		// TODO: AMD barycentrics as well? Seem to have different swizzle and 2 components rather than 3.
  		if (msl_options.is_ios() && !msl_options.supports_msl_version(2, 3))
  			SPIRV_CROSS_THROW("Barycentrics are only supported in MSL 2.3 and above on iOS.");
  		else if (!msl_options.supports_msl_version(2, 2))
  			SPIRV_CROSS_THROW("Barycentrics are only supported in MSL 2.2 and above on macOS.");
  		return "barycentric_coord, center_no_perspective";
  
  	default:
  		return "unsupported-built-in";
  	}
  }
  
  // Returns an MSL string type declaration for a SPIR-V builtin
  string CompilerMSL::builtin_type_decl(BuiltIn builtin, uint32_t id)
  {
  	const SPIREntryPoint &execution = get_entry_point();
  	switch (builtin)
  	{
  	// Vertex function in
  	case BuiltInVertexId:
  		return "uint";
  	case BuiltInVertexIndex:
  		return "uint";
  	case BuiltInBaseVertex:
  		return "uint";
  	case BuiltInInstanceId:
  		return "uint";
  	case BuiltInInstanceIndex:
  		return "uint";
  	case BuiltInBaseInstance:
  		return "uint";
  	case BuiltInDrawIndex:
  		SPIRV_CROSS_THROW("DrawIndex is not supported in MSL.");
  
  	// Vertex function out
  	case BuiltInClipDistance:
  	case BuiltInCullDistance:
  		return "float";
  	case BuiltInPointSize:
  		return "float";
  	case BuiltInPosition:
  		return "float4";
  	case BuiltInLayer:
  		return "uint";
  	case BuiltInViewportIndex:
  		if (!msl_options.supports_msl_version(2, 0))
  			SPIRV_CROSS_THROW("ViewportIndex requires Metal 2.0.");
  		return "uint";
  
  	// Tess. control function in
  	case BuiltInInvocationId:
  		return "uint";
  	case BuiltInPatchVertices:
  		return "uint";
  	case BuiltInPrimitiveId:
  		return "uint";
  
  	// Tess. control function out
  	case BuiltInTessLevelInner:
  		if (execution.model == ExecutionModelTessellationEvaluation)
  			return !execution.flags.get(ExecutionModeTriangles) ? "float2" : "float";
  		return "half";
  	case BuiltInTessLevelOuter:
  		if (execution.model == ExecutionModelTessellationEvaluation)
  			return !execution.flags.get(ExecutionModeTriangles) ? "float4" : "float";
  		return "half";
  
  	// Tess. evaluation function in
  	case BuiltInTessCoord:
  		return execution.flags.get(ExecutionModeTriangles) ? "float3" : "float2";
  
  	// Fragment function in
  	case BuiltInFrontFacing:
  		return "bool";
  	case BuiltInPointCoord:
  		return "float2";
  	case BuiltInFragCoord:
  		return "float4";
  	case BuiltInSampleId:
  		return "uint";
  	case BuiltInSampleMask:
  		return "uint";
  	case BuiltInSamplePosition:
  		return "float2";
  	case BuiltInViewIndex:
  		return "uint";
  
  	case BuiltInHelperInvocation:
  		return "bool";
  
  	case BuiltInBaryCoordNV:
  	case BuiltInBaryCoordNoPerspNV:
  		// Use the type as declared, can be 1, 2 or 3 components.
  		return type_to_glsl(get_variable_data_type(get<SPIRVariable>(id)));
  
  	// Fragment function out
  	case BuiltInFragDepth:
  		return "float";
  
  	case BuiltInFragStencilRefEXT:
  		return "uint";
  
  	// Compute function in
  	case BuiltInGlobalInvocationId:
  	case BuiltInLocalInvocationId:
  	case BuiltInNumWorkgroups:
  	case BuiltInWorkgroupId:
  		return "uint3";
  	case BuiltInLocalInvocationIndex:
  	case BuiltInNumSubgroups:
  	case BuiltInSubgroupId:
  	case BuiltInSubgroupSize:
  	case BuiltInSubgroupLocalInvocationId:
  		return "uint";
  	case BuiltInSubgroupEqMask:
  	case BuiltInSubgroupGeMask:
  	case BuiltInSubgroupGtMask:
  	case BuiltInSubgroupLeMask:
  	case BuiltInSubgroupLtMask:
  		return "uint4";
  
  	case BuiltInDeviceIndex:
  		return "int";
  
  	default:
  		return "unsupported-built-in-type";
  	}
  }
  
  // Returns the declaration of a built-in argument to a function
  string CompilerMSL::built_in_func_arg(BuiltIn builtin, bool prefix_comma)
  {
  	string bi_arg;
  	if (prefix_comma)
  		bi_arg += ", ";
  
  	// Handle HLSL-style 0-based vertex/instance index.
  	builtin_declaration = true;
  	bi_arg += builtin_type_decl(builtin);
  	bi_arg += " " + builtin_to_glsl(builtin, StorageClassInput);
  	bi_arg += " [[" + builtin_qualifier(builtin) + "]]";
  	builtin_declaration = false;
  
  	return bi_arg;
  }
  
  const SPIRType &CompilerMSL::get_physical_member_type(const SPIRType &type, uint32_t index) const
  {
  	if (member_is_remapped_physical_type(type, index))
  		return get<SPIRType>(get_extended_member_decoration(type.self, index, SPIRVCrossDecorationPhysicalTypeID));
  	else
  		return get<SPIRType>(type.member_types[index]);
  }
  
  SPIRType CompilerMSL::get_presumed_input_type(const SPIRType &ib_type, uint32_t index) const
  {
  	SPIRType type = get_physical_member_type(ib_type, index);
  	uint32_t loc = get_member_decoration(ib_type.self, index, DecorationLocation);
  	if (inputs_by_location.count(loc))
  	{
  		if (inputs_by_location.at(loc).vecsize > type.vecsize)
  			type.vecsize = inputs_by_location.at(loc).vecsize;
  	}
  	return type;
  }
  
  uint32_t CompilerMSL::get_declared_type_array_stride_msl(const SPIRType &type, bool is_packed, bool row_major) const
  {
  	// Array stride in MSL is always size * array_size. sizeof(float3) == 16,
  	// unlike GLSL and HLSL where array stride would be 16 and size 12.
  
  	// We could use parent type here and recurse, but that makes creating physical type remappings
  	// far more complicated. We'd rather just create the final type, and ignore having to create the entire type
  	// hierarchy in order to compute this value, so make a temporary type on the stack.
  
  	auto basic_type = type;
  	basic_type.array.clear();
  	basic_type.array_size_literal.clear();
  	uint32_t value_size = get_declared_type_size_msl(basic_type, is_packed, row_major);
  
  	uint32_t dimensions = uint32_t(type.array.size());
  	assert(dimensions > 0);
  	dimensions--;
  
  	// Multiply together every dimension, except the last one.
  	for (uint32_t dim = 0; dim < dimensions; dim++)
  	{
  		uint32_t array_size = to_array_size_literal(type, dim);
  		value_size *= max(array_size, 1u);
  	}
  
  	return value_size;
  }
  
  uint32_t CompilerMSL::get_declared_struct_member_array_stride_msl(const SPIRType &type, uint32_t index) const
  {
  	return get_declared_type_array_stride_msl(get_physical_member_type(type, index),
  	                                          member_is_packed_physical_type(type, index),
  	                                          has_member_decoration(type.self, index, DecorationRowMajor));
  }
  
  uint32_t CompilerMSL::get_declared_input_array_stride_msl(const SPIRType &type, uint32_t index) const
  {
  	return get_declared_type_array_stride_msl(get_presumed_input_type(type, index), false,
  	                                          has_member_decoration(type.self, index, DecorationRowMajor));
  }
  
  uint32_t CompilerMSL::get_declared_type_matrix_stride_msl(const SPIRType &type, bool packed, bool row_major) const
  {
  	// For packed matrices, we just use the size of the vector type.
  	// Otherwise, MatrixStride == alignment, which is the size of the underlying vector type.
  	if (packed)
  		return (type.width / 8) * ((row_major && type.columns > 1) ? type.columns : type.vecsize);
  	else
  		return get_declared_type_alignment_msl(type, false, row_major);
  }
  
  uint32_t CompilerMSL::get_declared_struct_member_matrix_stride_msl(const SPIRType &type, uint32_t index) const
  {
  	return get_declared_type_matrix_stride_msl(get_physical_member_type(type, index),
  	                                           member_is_packed_physical_type(type, index),
  	                                           has_member_decoration(type.self, index, DecorationRowMajor));
  }
  
  uint32_t CompilerMSL::get_declared_input_matrix_stride_msl(const SPIRType &type, uint32_t index) const
  {
  	return get_declared_type_matrix_stride_msl(get_presumed_input_type(type, index), false,
  	                                           has_member_decoration(type.self, index, DecorationRowMajor));
  }
  
  uint32_t CompilerMSL::get_declared_struct_size_msl(const SPIRType &struct_type, bool ignore_alignment,
                                                     bool ignore_padding) const
  {
  	// If we have a target size, that is the declared size as well.
  	if (!ignore_padding && has_extended_decoration(struct_type.self, SPIRVCrossDecorationPaddingTarget))
  		return get_extended_decoration(struct_type.self, SPIRVCrossDecorationPaddingTarget);
  
  	if (struct_type.member_types.empty())
  		return 0;
  
  	uint32_t mbr_cnt = uint32_t(struct_type.member_types.size());
  
  	// In MSL, a struct's alignment is equal to the maximum alignment of any of its members.
  	uint32_t alignment = 1;
  
  	if (!ignore_alignment)
  	{
  		for (uint32_t i = 0; i < mbr_cnt; i++)
  		{
  			uint32_t mbr_alignment = get_declared_struct_member_alignment_msl(struct_type, i);
  			alignment = max(alignment, mbr_alignment);
  		}
  	}
  
  	// Last member will always be matched to the final Offset decoration, but size of struct in MSL now depends
  	// on physical size in MSL, and the size of the struct itself is then aligned to struct alignment.
  	uint32_t spirv_offset = type_struct_member_offset(struct_type, mbr_cnt - 1);
  	uint32_t msl_size = spirv_offset + get_declared_struct_member_size_msl(struct_type, mbr_cnt - 1);
  	msl_size = (msl_size + alignment - 1) & ~(alignment - 1);
  	return msl_size;
  }
  
  // Returns the byte size of a struct member.
  uint32_t CompilerMSL::get_declared_type_size_msl(const SPIRType &type, bool is_packed, bool row_major) const
  {
  	switch (type.basetype)
  	{
  	case SPIRType::Unknown:
  	case SPIRType::Void:
  	case SPIRType::AtomicCounter:
  	case SPIRType::Image:
  	case SPIRType::SampledImage:
  	case SPIRType::Sampler:
  		SPIRV_CROSS_THROW("Querying size of opaque object.");
  
  	default:
  	{
  		if (!type.array.empty())
  		{
  			uint32_t array_size = to_array_size_literal(type);
  			return get_declared_type_array_stride_msl(type, is_packed, row_major) * max(array_size, 1u);
  		}
  
  		if (type.basetype == SPIRType::Struct)
  			return get_declared_struct_size_msl(type);
  
  		if (is_packed)
  		{
  			return type.vecsize * type.columns * (type.width / 8);
  		}
  		else
  		{
  			// An unpacked 3-element vector or matrix column is the same memory size as a 4-element.
  			uint32_t vecsize = type.vecsize;
  			uint32_t columns = type.columns;
  
  			if (row_major && columns > 1)
  				swap(vecsize, columns);
  
  			if (vecsize == 3)
  				vecsize = 4;
  
  			return vecsize * columns * (type.width / 8);
  		}
  	}
  	}
  }
  
  uint32_t CompilerMSL::get_declared_struct_member_size_msl(const SPIRType &type, uint32_t index) const
  {
  	return get_declared_type_size_msl(get_physical_member_type(type, index),
  	                                  member_is_packed_physical_type(type, index),
  	                                  has_member_decoration(type.self, index, DecorationRowMajor));
  }
  
  uint32_t CompilerMSL::get_declared_input_size_msl(const SPIRType &type, uint32_t index) const
  {
  	return get_declared_type_size_msl(get_presumed_input_type(type, index), false,
  	                                  has_member_decoration(type.self, index, DecorationRowMajor));
  }
  
  // Returns the byte alignment of a type.
  uint32_t CompilerMSL::get_declared_type_alignment_msl(const SPIRType &type, bool is_packed, bool row_major) const
  {
  	switch (type.basetype)
  	{
  	case SPIRType::Unknown:
  	case SPIRType::Void:
  	case SPIRType::AtomicCounter:
  	case SPIRType::Image:
  	case SPIRType::SampledImage:
  	case SPIRType::Sampler:
  		SPIRV_CROSS_THROW("Querying alignment of opaque object.");
  
  	case SPIRType::Double:
  		SPIRV_CROSS_THROW("double types are not supported in buffers in MSL.");
  
  	case SPIRType::Struct:
  	{
  		// In MSL, a struct's alignment is equal to the maximum alignment of any of its members.
  		uint32_t alignment = 1;
  		for (uint32_t i = 0; i < type.member_types.size(); i++)
  			alignment = max(alignment, uint32_t(get_declared_struct_member_alignment_msl(type, i)));
  		return alignment;
  	}
  
  	default:
  	{
  		if (type.basetype == SPIRType::Int64 && !msl_options.supports_msl_version(2, 3))
  			SPIRV_CROSS_THROW("long types in buffers are only supported in MSL 2.3 and above.");
  		if (type.basetype == SPIRType::UInt64 && !msl_options.supports_msl_version(2, 3))
  			SPIRV_CROSS_THROW("ulong types in buffers are only supported in MSL 2.3 and above.");
  		// Alignment of packed type is the same as the underlying component or column size.
  		// Alignment of unpacked type is the same as the vector size.
  		// Alignment of 3-elements vector is the same as 4-elements (including packed using column).
  		if (is_packed)
  		{
  			// If we have packed_T and friends, the alignment is always scalar.
  			return type.width / 8;
  		}
  		else
  		{
  			// This is the general rule for MSL. Size == alignment.
  			uint32_t vecsize = (row_major && type.columns > 1) ? type.columns : type.vecsize;
  			return (type.width / 8) * (vecsize == 3 ? 4 : vecsize);
  		}
  	}
  	}
  }
  
  uint32_t CompilerMSL::get_declared_struct_member_alignment_msl(const SPIRType &type, uint32_t index) const
  {
  	return get_declared_type_alignment_msl(get_physical_member_type(type, index),
  	                                       member_is_packed_physical_type(type, index),
  	                                       has_member_decoration(type.self, index, DecorationRowMajor));
  }
  
  uint32_t CompilerMSL::get_declared_input_alignment_msl(const SPIRType &type, uint32_t index) const
  {
  	return get_declared_type_alignment_msl(get_presumed_input_type(type, index), false,
  	                                       has_member_decoration(type.self, index, DecorationRowMajor));
  }
  
  bool CompilerMSL::skip_argument(uint32_t) const
  {
  	return false;
  }
  
  void CompilerMSL::analyze_sampled_image_usage()
  {
  	if (msl_options.swizzle_texture_samples)
  	{
  		SampledImageScanner scanner(*this);
  		traverse_all_reachable_opcodes(get<SPIRFunction>(ir.default_entry_point), scanner);
  	}
  }
  
  bool CompilerMSL::SampledImageScanner::handle(spv::Op opcode, const uint32_t *args, uint32_t length)
  {
  	switch (opcode)
  	{
  	case OpLoad:
  	case OpImage:
  	case OpSampledImage:
  	{
  		if (length < 3)
  			return false;
  
  		uint32_t result_type = args[0];
  		auto &type = compiler.get<SPIRType>(result_type);
  		if ((type.basetype != SPIRType::Image && type.basetype != SPIRType::SampledImage) || type.image.sampled != 1)
  			return true;
  
  		uint32_t id = args[1];
  		compiler.set<SPIRExpression>(id, "", result_type, true);
  		break;
  	}
  	case OpImageSampleExplicitLod:
  	case OpImageSampleProjExplicitLod:
  	case OpImageSampleDrefExplicitLod:
  	case OpImageSampleProjDrefExplicitLod:
  	case OpImageSampleImplicitLod:
  	case OpImageSampleProjImplicitLod:
  	case OpImageSampleDrefImplicitLod:
  	case OpImageSampleProjDrefImplicitLod:
  	case OpImageFetch:
  	case OpImageGather:
  	case OpImageDrefGather:
  		compiler.has_sampled_images =
  		    compiler.has_sampled_images || compiler.is_sampled_image_type(compiler.expression_type(args[2]));
  		compiler.needs_swizzle_buffer_def = compiler.needs_swizzle_buffer_def || compiler.has_sampled_images;
  		break;
  	default:
  		break;
  	}
  	return true;
  }
  
  // If a needed custom function wasn't added before, add it and force a recompile.
  void CompilerMSL::add_spv_func_and_recompile(SPVFuncImpl spv_func)
  {
  	if (spv_function_implementations.count(spv_func) == 0)
  	{
  		spv_function_implementations.insert(spv_func);
  		suppress_missing_prototypes = true;
  		force_recompile();
  	}
  }
  
  bool CompilerMSL::OpCodePreprocessor::handle(Op opcode, const uint32_t *args, uint32_t length)
  {
  	// Since MSL exists in a single execution scope, function prototype declarations are not
  	// needed, and clutter the output. If secondary functions are output (either as a SPIR-V
  	// function implementation or as indicated by the presence of OpFunctionCall), then set
  	// suppress_missing_prototypes to suppress compiler warnings of missing function prototypes.
  
  	// Mark if the input requires the implementation of an SPIR-V function that does not exist in Metal.
  	SPVFuncImpl spv_func = get_spv_func_impl(opcode, args);
  	if (spv_func != SPVFuncImplNone)
  	{
  		compiler.spv_function_implementations.insert(spv_func);
  		suppress_missing_prototypes = true;
  	}
  
  	switch (opcode)
  	{
  
  	case OpFunctionCall:
  		suppress_missing_prototypes = true;
  		break;
  
  	// Emulate texture2D atomic operations
  	case OpImageTexelPointer:
  	{
  		auto *var = compiler.maybe_get_backing_variable(args[2]);
  		image_pointers[args[1]] = var ? var->self : ID(0);
  		break;
  	}
  
  	case OpImageWrite:
  		if (!compiler.msl_options.supports_msl_version(2, 2))
  			uses_resource_write = true;
  		break;
  
  	case OpStore:
  		check_resource_write(args[0]);
  		break;
  
  	// Emulate texture2D atomic operations
  	case OpAtomicExchange:
  	case OpAtomicCompareExchange:
  	case OpAtomicCompareExchangeWeak:
  	case OpAtomicIIncrement:
  	case OpAtomicIDecrement:
  	case OpAtomicIAdd:
  	case OpAtomicISub:
  	case OpAtomicSMin:
  	case OpAtomicUMin:
  	case OpAtomicSMax:
  	case OpAtomicUMax:
  	case OpAtomicAnd:
  	case OpAtomicOr:
  	case OpAtomicXor:
  	{
  		uses_atomics = true;
  		auto it = image_pointers.find(args[2]);
  		if (it != image_pointers.end())
  		{
  			compiler.atomic_image_vars.insert(it->second);
  		}
  		check_resource_write(args[2]);
  		break;
  	}
  
  	case OpAtomicStore:
  	{
  		uses_atomics = true;
  		auto it = image_pointers.find(args[0]);
  		if (it != image_pointers.end())
  		{
  			compiler.atomic_image_vars.insert(it->second);
  		}
  		check_resource_write(args[0]);
  		break;
  	}
  
  	case OpAtomicLoad:
  	{
  		uses_atomics = true;
  		auto it = image_pointers.find(args[2]);
  		if (it != image_pointers.end())
  		{
  			compiler.atomic_image_vars.insert(it->second);
  		}
  		break;
  	}
  
  	case OpGroupNonUniformInverseBallot:
  		needs_subgroup_invocation_id = true;
  		break;
  
  	case OpGroupNonUniformBallotFindLSB:
  	case OpGroupNonUniformBallotFindMSB:
  		needs_subgroup_size = true;
  		break;
  
  	case OpGroupNonUniformBallotBitCount:
  		if (args[3] == GroupOperationReduce)
  			needs_subgroup_size = true;
  		else
  			needs_subgroup_invocation_id = true;
  		break;
  
  	case OpArrayLength:
  	{
  		auto *var = compiler.maybe_get_backing_variable(args[2]);
  		if (var)
  			compiler.buffers_requiring_array_length.insert(var->self);
  		break;
  	}
  
  	case OpInBoundsAccessChain:
  	case OpAccessChain:
  	case OpPtrAccessChain:
  	{
  		// OpArrayLength might want to know if taking ArrayLength of an array of SSBOs.
  		uint32_t result_type = args[0];
  		uint32_t id = args[1];
  		uint32_t ptr = args[2];
  
  		compiler.set<SPIRExpression>(id, "", result_type, true);
  		compiler.register_read(id, ptr, true);
  		compiler.ir.ids[id].set_allow_type_rewrite();
  		break;
  	}
  
  	case OpExtInst:
  	{
  		uint32_t extension_set = args[2];
  		if (compiler.get<SPIRExtension>(extension_set).ext == SPIRExtension::GLSL)
  		{
  			auto op_450 = static_cast<GLSLstd450>(args[3]);
  			switch (op_450)
  			{
  			case GLSLstd450InterpolateAtCentroid:
  			case GLSLstd450InterpolateAtSample:
  			case GLSLstd450InterpolateAtOffset:
  			{
  				if (!compiler.msl_options.supports_msl_version(2, 3))
  					SPIRV_CROSS_THROW("Pull-model interpolation requires MSL 2.3.");
  				// Fragment varyings used with pull-model interpolation need special handling,
  				// due to the way pull-model interpolation works in Metal.
  				auto *var = compiler.maybe_get_backing_variable(args[4]);
  				if (var)
  				{
  					compiler.pull_model_inputs.insert(var->self);
  					auto &var_type = compiler.get_variable_element_type(*var);
  					// In addition, if this variable has a 'Sample' decoration, we need the sample ID
  					// in order to do default interpolation.
  					if (compiler.has_decoration(var->self, DecorationSample))
  					{
  						needs_sample_id = true;
  					}
  					else if (var_type.basetype == SPIRType::Struct)
  					{
  						// Now we need to check each member and see if it has this decoration.
  						for (uint32_t i = 0; i < var_type.member_types.size(); ++i)
  						{
  							if (compiler.has_member_decoration(var_type.self, i, DecorationSample))
  							{
  								needs_sample_id = true;
  								break;
  							}
  						}
  					}
  				}
  				break;
  			}
  			default:
  				break;
  			}
  		}
  		break;
  	}
  
  	default:
  		break;
  	}
  
  	// If it has one, keep track of the instruction's result type, mapped by ID
  	uint32_t result_type, result_id;
  	if (compiler.instruction_to_result_type(result_type, result_id, opcode, args, length))
  		result_types[result_id] = result_type;
  
  	return true;
  }
  
  // If the variable is a Uniform or StorageBuffer, mark that a resource has been written to.
  void CompilerMSL::OpCodePreprocessor::check_resource_write(uint32_t var_id)
  {
  	auto *p_var = compiler.maybe_get_backing_variable(var_id);
  	StorageClass sc = p_var ? p_var->storage : StorageClassMax;
  	if (!compiler.msl_options.supports_msl_version(2, 1) &&
  	    (sc == StorageClassUniform || sc == StorageClassStorageBuffer))
  		uses_resource_write = true;
  }
  
  // Returns an enumeration of a SPIR-V function that needs to be output for certain Op codes.
  CompilerMSL::SPVFuncImpl CompilerMSL::OpCodePreprocessor::get_spv_func_impl(Op opcode, const uint32_t *args)
  {
  	switch (opcode)
  	{
  	case OpFMod:
  		return SPVFuncImplMod;
  
  	case OpFAdd:
  	case OpFSub:
  		if (compiler.msl_options.invariant_float_math ||
  		    compiler.has_decoration(args[1], DecorationNoContraction))
  		{
  			return opcode == OpFAdd ? SPVFuncImplFAdd : SPVFuncImplFSub;
  		}
  		break;
  
  	case OpFMul:
  	case OpOuterProduct:
  	case OpMatrixTimesVector:
  	case OpVectorTimesMatrix:
  	case OpMatrixTimesMatrix:
  		if (compiler.msl_options.invariant_float_math ||
  		    compiler.has_decoration(args[1], DecorationNoContraction))
  		{
  			return SPVFuncImplFMul;
  		}
  		break;
  
  	case OpTypeArray:
  	{
  		// Allow Metal to use the array<T> template to make arrays a value type
  		return SPVFuncImplUnsafeArray;
  	}
  
  	// Emulate texture2D atomic operations
  	case OpAtomicExchange:
  	case OpAtomicCompareExchange:
  	case OpAtomicCompareExchangeWeak:
  	case OpAtomicIIncrement:
  	case OpAtomicIDecrement:
  	case OpAtomicIAdd:
  	case OpAtomicISub:
  	case OpAtomicSMin:
  	case OpAtomicUMin:
  	case OpAtomicSMax:
  	case OpAtomicUMax:
  	case OpAtomicAnd:
  	case OpAtomicOr:
  	case OpAtomicXor:
  	case OpAtomicLoad:
  	case OpAtomicStore:
  	{
  		auto it = image_pointers.find(args[opcode == OpAtomicStore ? 0 : 2]);
  		if (it != image_pointers.end())
  		{
  			uint32_t tid = compiler.get<SPIRVariable>(it->second).basetype;
  			if (tid && compiler.get<SPIRType>(tid).image.dim == Dim2D)
  				return SPVFuncImplImage2DAtomicCoords;
  		}
  		break;
  	}
  
  	case OpImageFetch:
  	case OpImageRead:
  	case OpImageWrite:
  	{
  		// Retrieve the image type, and if it's a Buffer, emit a texel coordinate function
  		uint32_t tid = result_types[args[opcode == OpImageWrite ? 0 : 2]];
  		if (tid && compiler.get<SPIRType>(tid).image.dim == DimBuffer && !compiler.msl_options.texture_buffer_native)
  			return SPVFuncImplTexelBufferCoords;
  		break;
  	}
  
  	case OpExtInst:
  	{
  		uint32_t extension_set = args[2];
  		if (compiler.get<SPIRExtension>(extension_set).ext == SPIRExtension::GLSL)
  		{
  			auto op_450 = static_cast<GLSLstd450>(args[3]);
  			switch (op_450)
  			{
  			case GLSLstd450Radians:
  				return SPVFuncImplRadians;
  			case GLSLstd450Degrees:
  				return SPVFuncImplDegrees;
  			case GLSLstd450FindILsb:
  				return SPVFuncImplFindILsb;
  			case GLSLstd450FindSMsb:
  				return SPVFuncImplFindSMsb;
  			case GLSLstd450FindUMsb:
  				return SPVFuncImplFindUMsb;
  			case GLSLstd450SSign:
  				return SPVFuncImplSSign;
  			case GLSLstd450Reflect:
  			{
  				auto &type = compiler.get<SPIRType>(args[0]);
  				if (type.vecsize == 1)
  					return SPVFuncImplReflectScalar;
  				break;
  			}
  			case GLSLstd450Refract:
  			{
  				auto &type = compiler.get<SPIRType>(args[0]);
  				if (type.vecsize == 1)
  					return SPVFuncImplRefractScalar;
  				break;
  			}
  			case GLSLstd450FaceForward:
  			{
  				auto &type = compiler.get<SPIRType>(args[0]);
  				if (type.vecsize == 1)
  					return SPVFuncImplFaceForwardScalar;
  				break;
  			}
  			case GLSLstd450MatrixInverse:
  			{
  				auto &mat_type = compiler.get<SPIRType>(args[0]);
  				switch (mat_type.columns)
  				{
  				case 2:
  					return SPVFuncImplInverse2x2;
  				case 3:
  					return SPVFuncImplInverse3x3;
  				case 4:
  					return SPVFuncImplInverse4x4;
  				default:
  					break;
  				}
  				break;
  			}
  			default:
  				break;
  			}
  		}
  		break;
  	}
  
  	case OpGroupNonUniformBroadcast:
  		return SPVFuncImplSubgroupBroadcast;
  
  	case OpGroupNonUniformBroadcastFirst:
  		return SPVFuncImplSubgroupBroadcastFirst;
  
  	case OpGroupNonUniformBallot:
  		return SPVFuncImplSubgroupBallot;
  
  	case OpGroupNonUniformInverseBallot:
  	case OpGroupNonUniformBallotBitExtract:
  		return SPVFuncImplSubgroupBallotBitExtract;
  
  	case OpGroupNonUniformBallotFindLSB:
  		return SPVFuncImplSubgroupBallotFindLSB;
  
  	case OpGroupNonUniformBallotFindMSB:
  		return SPVFuncImplSubgroupBallotFindMSB;
  
  	case OpGroupNonUniformBallotBitCount:
  		return SPVFuncImplSubgroupBallotBitCount;
  
  	case OpGroupNonUniformAllEqual:
  		return SPVFuncImplSubgroupAllEqual;
  
  	case OpGroupNonUniformShuffle:
  		return SPVFuncImplSubgroupShuffle;
  
  	case OpGroupNonUniformShuffleXor:
  		return SPVFuncImplSubgroupShuffleXor;
  
  	case OpGroupNonUniformShuffleUp:
  		return SPVFuncImplSubgroupShuffleUp;
  
  	case OpGroupNonUniformShuffleDown:
  		return SPVFuncImplSubgroupShuffleDown;
  
  	case OpGroupNonUniformQuadBroadcast:
  		return SPVFuncImplQuadBroadcast;
  
  	case OpGroupNonUniformQuadSwap:
  		return SPVFuncImplQuadSwap;
  
  	default:
  		break;
  	}
  	return SPVFuncImplNone;
  }
  
  // Sort both type and meta member content based on builtin status (put builtins at end),
  // then by the required sorting aspect.
  void CompilerMSL::MemberSorter::sort()
  {
  	// Create a temporary array of consecutive member indices and sort it based on how
  	// the members should be reordered, based on builtin and sorting aspect meta info.
  	size_t mbr_cnt = type.member_types.size();
  	SmallVector<uint32_t> mbr_idxs(mbr_cnt);
  	std::iota(mbr_idxs.begin(), mbr_idxs.end(), 0); // Fill with consecutive indices
  	std::stable_sort(mbr_idxs.begin(), mbr_idxs.end(), *this); // Sort member indices based on sorting aspect
  
  	bool sort_is_identity = true;
  	for (uint32_t mbr_idx = 0; mbr_idx < mbr_cnt; mbr_idx++)
  	{
  		if (mbr_idx != mbr_idxs[mbr_idx])
  		{
  			sort_is_identity = false;
  			break;
  		}
  	}
  
  	if (sort_is_identity)
  		return;
  
  	if (meta.members.size() < type.member_types.size())
  	{
  		// This should never trigger in normal circumstances, but to be safe.
  		meta.members.resize(type.member_types.size());
  	}
  
  	// Move type and meta member info to the order defined by the sorted member indices.
  	// This is done by creating temporary copies of both member types and meta, and then
  	// copying back to the original content at the sorted indices.
  	auto mbr_types_cpy = type.member_types;
  	auto mbr_meta_cpy = meta.members;
  	for (uint32_t mbr_idx = 0; mbr_idx < mbr_cnt; mbr_idx++)
  	{
  		type.member_types[mbr_idx] = mbr_types_cpy[mbr_idxs[mbr_idx]];
  		meta.members[mbr_idx] = mbr_meta_cpy[mbr_idxs[mbr_idx]];
  	}
  
  	if (sort_aspect == SortAspect::Offset)
  	{
  		// If we're sorting by Offset, this might affect user code which accesses a buffer block.
  		// We will need to redirect member indices from one index to sorted index.
  		type.member_type_index_redirection = std::move(mbr_idxs);
  	}
  }
  
  bool CompilerMSL::MemberSorter::operator()(uint32_t mbr_idx1, uint32_t mbr_idx2)
  {
  	auto &mbr_meta1 = meta.members[mbr_idx1];
  	auto &mbr_meta2 = meta.members[mbr_idx2];
  
  	if (sort_aspect == LocationThenBuiltInType)
  	{
  		// Sort first by builtin status (put builtins at end), then by the sorting aspect.
  		if (mbr_meta1.builtin != mbr_meta2.builtin)
  			return mbr_meta2.builtin;
  		else if (mbr_meta1.builtin)
  			return mbr_meta1.builtin_type < mbr_meta2.builtin_type;
  		else if (mbr_meta1.location == mbr_meta2.location)
  			return mbr_meta1.component < mbr_meta2.component;
  		else
  			return mbr_meta1.location < mbr_meta2.location;
  	}
  	else
  		return mbr_meta1.offset < mbr_meta2.offset;
  }
  
  CompilerMSL::MemberSorter::MemberSorter(SPIRType &t, Meta &m, SortAspect sa)
      : type(t)
      , meta(m)
      , sort_aspect(sa)
  {
  	// Ensure enough meta info is available
  	meta.members.resize(max(type.member_types.size(), meta.members.size()));
  }
  
  void CompilerMSL::remap_constexpr_sampler(VariableID id, const MSLConstexprSampler &sampler)
  {
  	auto &type = get<SPIRType>(get<SPIRVariable>(id).basetype);
  	if (type.basetype != SPIRType::SampledImage && type.basetype != SPIRType::Sampler)
  		SPIRV_CROSS_THROW("Can only remap SampledImage and Sampler type.");
  	if (!type.array.empty())
  		SPIRV_CROSS_THROW("Can not remap array of samplers.");
  	constexpr_samplers_by_id[id] = sampler;
  }
  
  void CompilerMSL::remap_constexpr_sampler_by_binding(uint32_t desc_set, uint32_t binding,
                                                       const MSLConstexprSampler &sampler)
  {
  	constexpr_samplers_by_binding[{ desc_set, binding }] = sampler;
  }
  
  void CompilerMSL::cast_from_builtin_load(uint32_t source_id, std::string &expr, const SPIRType &expr_type)
  {
  	auto *var = maybe_get_backing_variable(source_id);
  	if (var)
  		source_id = var->self;
  
  	// Only interested in standalone builtin variables.
  	if (!has_decoration(source_id, DecorationBuiltIn))
  		return;
  
  	auto builtin = static_cast<BuiltIn>(get_decoration(source_id, DecorationBuiltIn));
  	auto expected_type = expr_type.basetype;
  	auto expected_width = expr_type.width;
  	switch (builtin)
  	{
  	case BuiltInGlobalInvocationId:
  	case BuiltInLocalInvocationId:
  	case BuiltInWorkgroupId:
  	case BuiltInLocalInvocationIndex:
  	case BuiltInWorkgroupSize:
  	case BuiltInNumWorkgroups:
  	case BuiltInLayer:
  	case BuiltInViewportIndex:
  	case BuiltInFragStencilRefEXT:
  	case BuiltInPrimitiveId:
  	case BuiltInSubgroupSize:
  	case BuiltInSubgroupLocalInvocationId:
  	case BuiltInViewIndex:
  	case BuiltInVertexIndex:
  	case BuiltInInstanceIndex:
  	case BuiltInBaseInstance:
  	case BuiltInBaseVertex:
  		expected_type = SPIRType::UInt;
  		expected_width = 32;
  		break;
  
  	case BuiltInTessLevelInner:
  	case BuiltInTessLevelOuter:
  		if (get_execution_model() == ExecutionModelTessellationControl)
  		{
  			expected_type = SPIRType::Half;
  			expected_width = 16;
  		}
  		break;
  
  	default:
  		break;
  	}
  
  	if (expected_type != expr_type.basetype)
  	{
  		if (!expr_type.array.empty() && (builtin == BuiltInTessLevelInner || builtin == BuiltInTessLevelOuter))
  		{
  			// Triggers when loading TessLevel directly as an array.
  			// Need explicit padding + cast.
  			auto wrap_expr = join(type_to_glsl(expr_type), "({ ");
  
  			uint32_t array_size = get_physical_tess_level_array_size(builtin);
  			for (uint32_t i = 0; i < array_size; i++)
  			{
  				if (array_size > 1)
  					wrap_expr += join("float(", expr, "[", i, "])");
  				else
  					wrap_expr += join("float(", expr, ")");
  				if (i + 1 < array_size)
  					wrap_expr += ", ";
  			}
  
  			if (get_execution_mode_bitset().get(ExecutionModeTriangles))
  				wrap_expr += ", 0.0";
  
  			wrap_expr += " })";
  			expr = std::move(wrap_expr);
  		}
  		else
  		{
  			// These are of different widths, so we cannot do a straight bitcast.
  			if (expected_width != expr_type.width)
  				expr = join(type_to_glsl(expr_type), "(", expr, ")");
  			else
  				expr = bitcast_expression(expr_type, expected_type, expr);
  		}
  	}
  
  	if (builtin == BuiltInTessCoord && get_entry_point().flags.get(ExecutionModeQuads) && expr_type.vecsize == 3)
  	{
  		// In SPIR-V, this is always a vec3, even for quads. In Metal, though, it's a float2 for quads.
  		// The code is expecting a float3, so we need to widen this.
  		expr = join("float3(", expr, ", 0)");
  	}
  }
  
  void CompilerMSL::cast_to_builtin_store(uint32_t target_id, std::string &expr, const SPIRType &expr_type)
  {
  	auto *var = maybe_get_backing_variable(target_id);
  	if (var)
  		target_id = var->self;
  
  	// Only interested in standalone builtin variables.
  	if (!has_decoration(target_id, DecorationBuiltIn))
  		return;
  
  	auto builtin = static_cast<BuiltIn>(get_decoration(target_id, DecorationBuiltIn));
  	auto expected_type = expr_type.basetype;
  	auto expected_width = expr_type.width;
  	switch (builtin)
  	{
  	case BuiltInLayer:
  	case BuiltInViewportIndex:
  	case BuiltInFragStencilRefEXT:
  	case BuiltInPrimitiveId:
  	case BuiltInViewIndex:
  		expected_type = SPIRType::UInt;
  		expected_width = 32;
  		break;
  
  	case BuiltInTessLevelInner:
  	case BuiltInTessLevelOuter:
  		expected_type = SPIRType::Half;
  		expected_width = 16;
  		break;
  
  	default:
  		break;
  	}
  
  	if (expected_type != expr_type.basetype)
  	{
  		if (expected_width != expr_type.width)
  		{
  			// These are of different widths, so we cannot do a straight bitcast.
  			auto type = expr_type;
  			type.basetype = expected_type;
  			type.width = expected_width;
  			expr = join(type_to_glsl(type), "(", expr, ")");
  		}
  		else
  		{
  			auto type = expr_type;
  			type.basetype = expected_type;
  			expr = bitcast_expression(type, expr_type.basetype, expr);
  		}
  	}
  }
  
  string CompilerMSL::to_initializer_expression(const SPIRVariable &var)
  {
  	// We risk getting an array initializer here with MSL. If we have an array.
  	// FIXME: We cannot handle non-constant arrays being initialized.
  	// We will need to inject spvArrayCopy here somehow ...
  	auto &type = get<SPIRType>(var.basetype);
  	string expr;
  	if (ir.ids[var.initializer].get_type() == TypeConstant &&
  	    (!type.array.empty() || type.basetype == SPIRType::Struct))
  		expr = constant_expression(get<SPIRConstant>(var.initializer));
  	else
  		expr = CompilerGLSL::to_initializer_expression(var);
  	// If the initializer has more vector components than the variable, add a swizzle.
  	// FIXME: This can't handle arrays or structs.
  	auto &init_type = expression_type(var.initializer);
  	if (type.array.empty() && type.basetype != SPIRType::Struct && init_type.vecsize > type.vecsize)
  		expr = enclose_expression(expr + vector_swizzle(type.vecsize, 0));
  	return expr;
  }
  
  string CompilerMSL::to_zero_initialized_expression(uint32_t)
  {
  	return "{}";
  }
  
  bool CompilerMSL::descriptor_set_is_argument_buffer(uint32_t desc_set) const
  {
  	if (!msl_options.argument_buffers)
  		return false;
  	if (desc_set >= kMaxArgumentBuffers)
  		return false;
  
  	return (argument_buffer_discrete_mask & (1u << desc_set)) == 0;
  }
  
  bool CompilerMSL::is_supported_argument_buffer_type(const SPIRType &type) const
  {
  	// Very specifically, image load-store in argument buffers are disallowed on MSL on iOS.
  	// But we won't know when the argument buffer is encoded whether this image will have
  	// a NonWritable decoration. So just use discrete arguments for all storage images
  	// on iOS.
  	bool is_storage_image = type.basetype == SPIRType::Image && type.image.sampled == 2;
  	bool is_supported_type = !msl_options.is_ios() || !is_storage_image;
  	return !type_is_msl_framebuffer_fetch(type) && is_supported_type;
  }
  
  void CompilerMSL::analyze_argument_buffers()
  {
  	// Gather all used resources and sort them out into argument buffers.
  	// Each argument buffer corresponds to a descriptor set in SPIR-V.
  	// The [[id(N)]] values used correspond to the resource mapping we have for MSL.
  	// Otherwise, the binding number is used, but this is generally not safe some types like
  	// combined image samplers and arrays of resources. Metal needs different indices here,
  	// while SPIR-V can have one descriptor set binding. To use argument buffers in practice,
  	// you will need to use the remapping from the API.
  	for (auto &id : argument_buffer_ids)
  		id = 0;
  
  	// Output resources, sorted by resource index & type.
  	struct Resource
  	{
  		SPIRVariable *var;
  		string name;
  		SPIRType::BaseType basetype;
  		uint32_t index;
  		uint32_t plane;
  	};
  	SmallVector<Resource> resources_in_set[kMaxArgumentBuffers];
  	SmallVector<uint32_t> inline_block_vars;
  
  	bool set_needs_swizzle_buffer[kMaxArgumentBuffers] = {};
  	bool set_needs_buffer_sizes[kMaxArgumentBuffers] = {};
  	bool needs_buffer_sizes = false;
  
  	ir.for_each_typed_id<SPIRVariable>([&](uint32_t self, SPIRVariable &var) {
  		if ((var.storage == StorageClassUniform || var.storage == StorageClassUniformConstant ||
  		     var.storage == StorageClassStorageBuffer) &&
  		    !is_hidden_variable(var))
  		{
  			uint32_t desc_set = get_decoration(self, DecorationDescriptorSet);
  			// Ignore if it's part of a push descriptor set.
  			if (!descriptor_set_is_argument_buffer(desc_set))
  				return;
  
  			uint32_t var_id = var.self;
  			auto &type = get_variable_data_type(var);
  
  			if (desc_set >= kMaxArgumentBuffers)
  				SPIRV_CROSS_THROW("Descriptor set index is out of range.");
  
  			const MSLConstexprSampler *constexpr_sampler = nullptr;
  			if (type.basetype == SPIRType::SampledImage || type.basetype == SPIRType::Sampler)
  			{
  				constexpr_sampler = find_constexpr_sampler(var_id);
  				if (constexpr_sampler)
  				{
  					// Mark this ID as a constexpr sampler for later in case it came from set/bindings.
  					constexpr_samplers_by_id[var_id] = *constexpr_sampler;
  				}
  			}
  
  			uint32_t binding = get_decoration(var_id, DecorationBinding);
  			if (type.basetype == SPIRType::SampledImage)
  			{
  				add_resource_name(var_id);
  
  				uint32_t plane_count = 1;
  				if (constexpr_sampler && constexpr_sampler->ycbcr_conversion_enable)
  					plane_count = constexpr_sampler->planes;
  
  				for (uint32_t i = 0; i < plane_count; i++)
  				{
  					uint32_t image_resource_index = get_metal_resource_index(var, SPIRType::Image, i);
  					resources_in_set[desc_set].push_back(
  					    { &var, to_name(var_id), SPIRType::Image, image_resource_index, i });
  				}
  
  				if (type.image.dim != DimBuffer && !constexpr_sampler)
  				{
  					uint32_t sampler_resource_index = get_metal_resource_index(var, SPIRType::Sampler);
  					resources_in_set[desc_set].push_back(
  					    { &var, to_sampler_expression(var_id), SPIRType::Sampler, sampler_resource_index, 0 });
  				}
  			}
  			else if (inline_uniform_blocks.count(SetBindingPair{ desc_set, binding }))
  			{
  				inline_block_vars.push_back(var_id);
  			}
  			else if (!constexpr_sampler && is_supported_argument_buffer_type(type))
  			{
  				// constexpr samplers are not declared as resources.
  				// Inline uniform blocks are always emitted at the end.
  				add_resource_name(var_id);
  				resources_in_set[desc_set].push_back(
  					{ &var, to_name(var_id), type.basetype, get_metal_resource_index(var, type.basetype), 0 });
  
  				// Emulate texture2D atomic operations
  				if (atomic_image_vars.count(var.self))
  				{
  					uint32_t buffer_resource_index = get_metal_resource_index(var, SPIRType::AtomicCounter, 0);
  					resources_in_set[desc_set].push_back(
  						{ &var, to_name(var_id) + "_atomic", SPIRType::Struct, buffer_resource_index, 0 });
  				}
  			}
  
  			// Check if this descriptor set needs a swizzle buffer.
  			if (needs_swizzle_buffer_def && is_sampled_image_type(type))
  				set_needs_swizzle_buffer[desc_set] = true;
  			else if (buffers_requiring_array_length.count(var_id) != 0)
  			{
  				set_needs_buffer_sizes[desc_set] = true;
  				needs_buffer_sizes = true;
  			}
  		}
  	});
  
  	if (needs_swizzle_buffer_def || needs_buffer_sizes)
  	{
  		uint32_t uint_ptr_type_id = 0;
  
  		// We might have to add a swizzle buffer resource to the set.
  		for (uint32_t desc_set = 0; desc_set < kMaxArgumentBuffers; desc_set++)
  		{
  			if (!set_needs_swizzle_buffer[desc_set] && !set_needs_buffer_sizes[desc_set])
  				continue;
  
  			if (uint_ptr_type_id == 0)
  			{
  				uint_ptr_type_id = ir.increase_bound_by(1);
  
  				// Create a buffer to hold extra data, including the swizzle constants.
  				SPIRType uint_type_pointer = get_uint_type();
  				uint_type_pointer.pointer = true;
  				uint_type_pointer.pointer_depth++;
  				uint_type_pointer.parent_type = get_uint_type_id();
  				uint_type_pointer.storage = StorageClassUniform;
  				set<SPIRType>(uint_ptr_type_id, uint_type_pointer);
  				set_decoration(uint_ptr_type_id, DecorationArrayStride, 4);
  			}
  
  			if (set_needs_swizzle_buffer[desc_set])
  			{
  				uint32_t var_id = ir.increase_bound_by(1);
  				auto &var = set<SPIRVariable>(var_id, uint_ptr_type_id, StorageClassUniformConstant);
  				set_name(var_id, "spvSwizzleConstants");
  				set_decoration(var_id, DecorationDescriptorSet, desc_set);
  				set_decoration(var_id, DecorationBinding, kSwizzleBufferBinding);
  				resources_in_set[desc_set].push_back(
  				    { &var, to_name(var_id), SPIRType::UInt, get_metal_resource_index(var, SPIRType::UInt), 0 });
  			}
  
  			if (set_needs_buffer_sizes[desc_set])
  			{
  				uint32_t var_id = ir.increase_bound_by(1);
  				auto &var = set<SPIRVariable>(var_id, uint_ptr_type_id, StorageClassUniformConstant);
  				set_name(var_id, "spvBufferSizeConstants");
  				set_decoration(var_id, DecorationDescriptorSet, desc_set);
  				set_decoration(var_id, DecorationBinding, kBufferSizeBufferBinding);
  				resources_in_set[desc_set].push_back(
  				    { &var, to_name(var_id), SPIRType::UInt, get_metal_resource_index(var, SPIRType::UInt), 0 });
  			}
  		}
  	}
  
  	// Now add inline uniform blocks.
  	for (uint32_t var_id : inline_block_vars)
  	{
  		auto &var = get<SPIRVariable>(var_id);
  		uint32_t desc_set = get_decoration(var_id, DecorationDescriptorSet);
  		add_resource_name(var_id);
  		resources_in_set[desc_set].push_back(
  		    { &var, to_name(var_id), SPIRType::Struct, get_metal_resource_index(var, SPIRType::Struct), 0 });
  	}
  
  	for (uint32_t desc_set = 0; desc_set < kMaxArgumentBuffers; desc_set++)
  	{
  		auto &resources = resources_in_set[desc_set];
  		if (resources.empty())
  			continue;
  
  		assert(descriptor_set_is_argument_buffer(desc_set));
  
  		uint32_t next_id = ir.increase_bound_by(3);
  		uint32_t type_id = next_id + 1;
  		uint32_t ptr_type_id = next_id + 2;
  		argument_buffer_ids[desc_set] = next_id;
  
  		auto &buffer_type = set<SPIRType>(type_id);
  
  		buffer_type.basetype = SPIRType::Struct;
  
  		if ((argument_buffer_device_storage_mask & (1u << desc_set)) != 0)
  		{
  			buffer_type.storage = StorageClassStorageBuffer;
  			// Make sure the argument buffer gets marked as const device.
  			set_decoration(next_id, DecorationNonWritable);
  			// Need to mark the type as a Block to enable this.
  			set_decoration(type_id, DecorationBlock);
  		}
  		else
  			buffer_type.storage = StorageClassUniform;
  
  		set_name(type_id, join("spvDescriptorSetBuffer", desc_set));
  
  		auto &ptr_type = set<SPIRType>(ptr_type_id);
  		ptr_type = buffer_type;
  		ptr_type.pointer = true;
  		ptr_type.pointer_depth++;
  		ptr_type.parent_type = type_id;
  
  		uint32_t buffer_variable_id = next_id;
  		set<SPIRVariable>(buffer_variable_id, ptr_type_id, StorageClassUniform);
  		set_name(buffer_variable_id, join("spvDescriptorSet", desc_set));
  
  		// Ids must be emitted in ID order.
  		sort(begin(resources), end(resources), [&](const Resource &lhs, const Resource &rhs) -> bool {
  			return tie(lhs.index, lhs.basetype) < tie(rhs.index, rhs.basetype);
  		});
  
  		uint32_t member_index = 0;
  		uint32_t next_arg_buff_index = 0;
  		for (auto &resource : resources)
  		{
  			auto &var = *resource.var;
  			auto &type = get_variable_data_type(var);
  
  			// If needed, synthesize and add padding members.
  			// member_index and next_arg_buff_index are incremented when padding members are added.
  			if (msl_options.pad_argument_buffer_resources)
  			{
  				while (resource.index > next_arg_buff_index)
  				{
  					auto &rez_bind = get_argument_buffer_resource(desc_set, next_arg_buff_index);
  					switch (rez_bind.basetype)
  					{
  					case SPIRType::Void:
  					case SPIRType::Boolean:
  					case SPIRType::SByte:
  					case SPIRType::UByte:
  					case SPIRType::Short:
  					case SPIRType::UShort:
  					case SPIRType::Int:
  					case SPIRType::UInt:
  					case SPIRType::Int64:
  					case SPIRType::UInt64:
  					case SPIRType::AtomicCounter:
  					case SPIRType::Half:
  					case SPIRType::Float:
  					case SPIRType::Double:
  						add_argument_buffer_padding_buffer_type(buffer_type, member_index, next_arg_buff_index, rez_bind);
  						break;
  					case SPIRType::Image:
  						add_argument_buffer_padding_image_type(buffer_type, member_index, next_arg_buff_index, rez_bind);
  						break;
  					case SPIRType::Sampler:
  						add_argument_buffer_padding_sampler_type(buffer_type, member_index, next_arg_buff_index, rez_bind);
  						break;
  					case SPIRType::SampledImage:
  						if (next_arg_buff_index == rez_bind.msl_sampler)
  							add_argument_buffer_padding_sampler_type(buffer_type, member_index, next_arg_buff_index, rez_bind);
  						else
  							add_argument_buffer_padding_image_type(buffer_type, member_index, next_arg_buff_index, rez_bind);
  						break;
  					default:
  						break;
  					}
  				}
  
  				// Adjust the number of slots consumed by current member itself.
  				// If actual member is an array, allow runtime array resolution as well.
  				uint32_t elem_cnt = type.array.empty() ? 1 : to_array_size_literal(type);
  				if (elem_cnt == 0)
  					elem_cnt = get_resource_array_size(var.self);
  
  				next_arg_buff_index += elem_cnt;
  			}
  
  			string mbr_name = ensure_valid_name(resource.name, "m");
  			if (resource.plane > 0)
  				mbr_name += join(plane_name_suffix, resource.plane);
  			set_member_name(buffer_type.self, member_index, mbr_name);
  
  			if (resource.basetype == SPIRType::Sampler && type.basetype != SPIRType::Sampler)
  			{
  				// Have to synthesize a sampler type here.
  
  				bool type_is_array = !type.array.empty();
  				uint32_t sampler_type_id = ir.increase_bound_by(type_is_array ? 2 : 1);
  				auto &new_sampler_type = set<SPIRType>(sampler_type_id);
  				new_sampler_type.basetype = SPIRType::Sampler;
  				new_sampler_type.storage = StorageClassUniformConstant;
  
  				if (type_is_array)
  				{
  					uint32_t sampler_type_array_id = sampler_type_id + 1;
  					auto &sampler_type_array = set<SPIRType>(sampler_type_array_id);
  					sampler_type_array = new_sampler_type;
  					sampler_type_array.array = type.array;
  					sampler_type_array.array_size_literal = type.array_size_literal;
  					sampler_type_array.parent_type = sampler_type_id;
  					buffer_type.member_types.push_back(sampler_type_array_id);
  				}
  				else
  					buffer_type.member_types.push_back(sampler_type_id);
  			}
  			else
  			{
  				uint32_t binding = get_decoration(var.self, DecorationBinding);
  				SetBindingPair pair = { desc_set, binding };
  
  				if (resource.basetype == SPIRType::Image || resource.basetype == SPIRType::Sampler ||
  				    resource.basetype == SPIRType::SampledImage)
  				{
  					// Drop pointer information when we emit the resources into a struct.
  					buffer_type.member_types.push_back(get_variable_data_type_id(var));
  					if (resource.plane == 0)
  						set_qualified_name(var.self, join(to_name(buffer_variable_id), ".", mbr_name));
  				}
  				else if (buffers_requiring_dynamic_offset.count(pair))
  				{
  					// Don't set the qualified name here; we'll define a variable holding the corrected buffer address later.
  					buffer_type.member_types.push_back(var.basetype);
  					buffers_requiring_dynamic_offset[pair].second = var.self;
  				}
  				else if (inline_uniform_blocks.count(pair))
  				{
  					// Put the buffer block itself into the argument buffer.
  					buffer_type.member_types.push_back(get_variable_data_type_id(var));
  					set_qualified_name(var.self, join(to_name(buffer_variable_id), ".", mbr_name));
  				}
  				else if (atomic_image_vars.count(var.self))
  				{
  					// Emulate texture2D atomic operations.
  					// Don't set the qualified name: it's already set for this variable,
  					// and the code that references the buffer manually appends "_atomic"
  					// to the name.
  					uint32_t offset = ir.increase_bound_by(2);
  					uint32_t atomic_type_id = offset;
  					uint32_t type_ptr_id = offset + 1;
  
  					SPIRType atomic_type;
  					atomic_type.basetype = SPIRType::AtomicCounter;
  					atomic_type.width = 32;
  					atomic_type.vecsize = 1;
  					set<SPIRType>(atomic_type_id, atomic_type);
  
  					atomic_type.pointer = true;
  					atomic_type.pointer_depth++;
  					atomic_type.parent_type = atomic_type_id;
  					atomic_type.storage = StorageClassStorageBuffer;
  					auto &atomic_ptr_type = set<SPIRType>(type_ptr_id, atomic_type);
  					atomic_ptr_type.self = atomic_type_id;
  
  					buffer_type.member_types.push_back(type_ptr_id);
  				}
  				else
  				{
  					// Resources will be declared as pointers not references, so automatically dereference as appropriate.
  					buffer_type.member_types.push_back(var.basetype);
  					if (type.array.empty())
  						set_qualified_name(var.self, join("(*", to_name(buffer_variable_id), ".", mbr_name, ")"));
  					else
  						set_qualified_name(var.self, join(to_name(buffer_variable_id), ".", mbr_name));
  				}
  			}
  
  			set_extended_member_decoration(buffer_type.self, member_index, SPIRVCrossDecorationResourceIndexPrimary,
  			                               resource.index);
  			set_extended_member_decoration(buffer_type.self, member_index, SPIRVCrossDecorationInterfaceOrigID,
  			                               var.self);
  			member_index++;
  		}
  	}
  }
  
  // Return the resource type of the app-provided resources for the descriptor set,
  // that matches the resource index of the argument buffer index.
  // This is a two-step lookup, first lookup the resource binding number from the argument buffer index,
  // then lookup the resource binding using the binding number.
  MSLResourceBinding &CompilerMSL::get_argument_buffer_resource(uint32_t desc_set, uint32_t arg_idx)
  {
  	auto stage = get_entry_point().model;
  	StageSetBinding arg_idx_tuple = { stage, desc_set, arg_idx };
  	auto arg_itr = resource_arg_buff_idx_to_binding_number.find(arg_idx_tuple);
  	if (arg_itr != end(resource_arg_buff_idx_to_binding_number))
  	{
  		StageSetBinding bind_tuple = { stage, desc_set, arg_itr->second };
  		auto bind_itr = resource_bindings.find(bind_tuple);
  		if (bind_itr != end(resource_bindings))
  			return bind_itr->second.first;
  	}
  	SPIRV_CROSS_THROW("Argument buffer resource base type could not be determined. When padding argument buffer "
  	                  "elements, all descriptor set resources must be supplied with a base type by the app.");
  }
  
  // Adds an argument buffer padding argument buffer type as one or more members of the struct type at the member index.
  // Metal does not support arrays of buffers, so these are emitted as multiple struct members.
  void CompilerMSL::add_argument_buffer_padding_buffer_type(SPIRType &struct_type, uint32_t &mbr_idx,
                                                            uint32_t &arg_buff_index, MSLResourceBinding &rez_bind)
  {
  	if (!argument_buffer_padding_buffer_type_id)
  	{
  		uint32_t buff_type_id = ir.increase_bound_by(2);
  		auto &buff_type = set<SPIRType>(buff_type_id);
  		buff_type.basetype = rez_bind.basetype;
  		buff_type.storage = StorageClassUniformConstant;
  
  		uint32_t ptr_type_id = buff_type_id + 1;
  		auto &ptr_type = set<SPIRType>(ptr_type_id);
  		ptr_type = buff_type;
  		ptr_type.pointer = true;
  		ptr_type.pointer_depth++;
  		ptr_type.parent_type = buff_type_id;
  
  		argument_buffer_padding_buffer_type_id = ptr_type_id;
  	}
  
  	for (uint32_t rez_idx = 0; rez_idx < rez_bind.count; rez_idx++)
  		add_argument_buffer_padding_type(argument_buffer_padding_buffer_type_id, struct_type, mbr_idx, arg_buff_index, 1);
  }
  
  // Adds an argument buffer padding argument image type as a member of the struct type at the member index.
  void CompilerMSL::add_argument_buffer_padding_image_type(SPIRType &struct_type, uint32_t &mbr_idx,
                                                           uint32_t &arg_buff_index, MSLResourceBinding &rez_bind)
  {
  	if (!argument_buffer_padding_image_type_id)
  	{
  		uint32_t base_type_id = ir.increase_bound_by(2);
  		auto &base_type = set<SPIRType>(base_type_id);
  		base_type.basetype = SPIRType::Float;
  		base_type.width = 32;
  
  		uint32_t img_type_id = base_type_id + 1;
  		auto &img_type = set<SPIRType>(img_type_id);
  		img_type.basetype = SPIRType::Image;
  		img_type.storage = StorageClassUniformConstant;
  
  		img_type.image.type = base_type_id;
  		img_type.image.dim = Dim2D;
  		img_type.image.depth = false;
  		img_type.image.arrayed = false;
  		img_type.image.ms = false;
  		img_type.image.sampled = 1;
  		img_type.image.format = ImageFormatUnknown;
  		img_type.image.access = AccessQualifierMax;
  
  		argument_buffer_padding_image_type_id = img_type_id;
  	}
  
  	add_argument_buffer_padding_type(argument_buffer_padding_image_type_id, struct_type, mbr_idx, arg_buff_index, rez_bind.count);
  }
  
  // Adds an argument buffer padding argument sampler type as a member of the struct type at the member index.
  void CompilerMSL::add_argument_buffer_padding_sampler_type(SPIRType &struct_type, uint32_t &mbr_idx,
                                                             uint32_t &arg_buff_index, MSLResourceBinding &rez_bind)
  {
  	if (!argument_buffer_padding_sampler_type_id)
  	{
  		uint32_t samp_type_id = ir.increase_bound_by(1);
  		auto &samp_type = set<SPIRType>(samp_type_id);
  		samp_type.basetype = SPIRType::Sampler;
  		samp_type.storage = StorageClassUniformConstant;
  
  		argument_buffer_padding_sampler_type_id = samp_type_id;
  	}
  
  	add_argument_buffer_padding_type(argument_buffer_padding_sampler_type_id, struct_type, mbr_idx, arg_buff_index, rez_bind.count);
  }
  
  // Adds the argument buffer padding argument type as a member of the struct type at the member index.
  // Advances both arg_buff_index and mbr_idx to next argument slots.
  void CompilerMSL::add_argument_buffer_padding_type(uint32_t mbr_type_id, SPIRType &struct_type, uint32_t &mbr_idx,
                                                     uint32_t &arg_buff_index, uint32_t count)
  {
  	uint32_t type_id = mbr_type_id;
  	if (count > 1)
  	{
  		uint32_t ary_type_id = ir.increase_bound_by(1);
  		auto &ary_type = set<SPIRType>(ary_type_id);
  		ary_type = get<SPIRType>(type_id);
  		ary_type.array.push_back(count);
  		ary_type.array_size_literal.push_back(true);
  		ary_type.parent_type = type_id;
  		type_id = ary_type_id;
  	}
  
  	set_member_name(struct_type.self, mbr_idx, join("_m", arg_buff_index, "_pad"));
  	set_extended_member_decoration(struct_type.self, mbr_idx, SPIRVCrossDecorationResourceIndexPrimary, arg_buff_index);
  	struct_type.member_types.push_back(type_id);
  
  	arg_buff_index += count;
  	mbr_idx++;
  }
  
  void CompilerMSL::activate_argument_buffer_resources()
  {
  	// For ABI compatibility, force-enable all resources which are part of argument buffers.
  	ir.for_each_typed_id<SPIRVariable>([&](uint32_t self, const SPIRVariable &) {
  		if (!has_decoration(self, DecorationDescriptorSet))
  			return;
  
  		uint32_t desc_set = get_decoration(self, DecorationDescriptorSet);
  		if (descriptor_set_is_argument_buffer(desc_set))
  			active_interface_variables.insert(self);
  	});
  }
  
  bool CompilerMSL::using_builtin_array() const
  {
  	return msl_options.force_native_arrays || is_using_builtin_array;
  }
  
  void CompilerMSL::set_combined_sampler_suffix(const char *suffix)
  {
  	sampler_name_suffix = suffix;
  }
  
  const char *CompilerMSL::get_combined_sampler_suffix() const
  {
  	return sampler_name_suffix.c_str();
  }
  
  void CompilerMSL::emit_block_hints(const SPIRBlock &)
  {
  }
  
  string CompilerMSL::additional_fixed_sample_mask_str() const
  {
  	char print_buffer[32];
  	sprintf(print_buffer, "0x%x", msl_options.additional_fixed_sample_mask);
  	return print_buffer;
  }
  