text: /*
   * Copyright © 2013 Intel Corporation
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice (including the next
   * paragraph) shall be included in all copies or substantial portions of the
   * Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   * DEALINGS IN THE SOFTWARE.
   */
  
  #include "glsl_parser_extras.h"
  #include "ir.h"
  #include "ir_uniform.h"
  #include "linker.h"
  #include "main/macros.h"
  
  namespace {
     /*
      * Atomic counter uniform as seen by the program.
      */
     struct active_atomic_counter_uniform {
        unsigned uniform_loc;
        ir_variable *var;
     };
  
     /*
      * Atomic counter buffer referenced by the program.  There is a one
      * to one correspondence between these and the objects that can be
      * queried using glGetActiveAtomicCounterBufferiv().
      */
     struct active_atomic_buffer {
        active_atomic_buffer()
           : uniforms(0), num_uniforms(0), stage_counter_references(), size(0)
        {}
  
        ~active_atomic_buffer()
        {
           free(uniforms);
        }
  
        void push_back(unsigned uniform_loc, ir_variable *var)
        {
           active_atomic_counter_uniform *new_uniforms;
  
           new_uniforms = (active_atomic_counter_uniform *)
              realloc(uniforms, sizeof(active_atomic_counter_uniform) *
                      (num_uniforms + 1));
  
           if (new_uniforms == NULL) {
              _mesa_error_no_memory(__func__);
              return;
           }
  
           uniforms = new_uniforms;
           uniforms[num_uniforms].uniform_loc = uniform_loc;
           uniforms[num_uniforms].var = var;
           num_uniforms++;
        }
  
        active_atomic_counter_uniform *uniforms;
        unsigned num_uniforms;
        unsigned stage_counter_references[MESA_SHADER_STAGES];
        unsigned size;
     };
  
     int
     cmp_actives(const void *a, const void *b)
     {
        const active_atomic_counter_uniform *const first = (active_atomic_counter_uniform *) a;
        const active_atomic_counter_uniform *const second = (active_atomic_counter_uniform *) b;
  
        return int(first->var->data.offset) - int(second->var->data.offset);
     }
  
     bool
     check_atomic_counters_overlap(const ir_variable *x, const ir_variable *y)
     {
        return ((x->data.offset >= y->data.offset &&
                 x->data.offset < y->data.offset + y->type->atomic_size()) ||
                (y->data.offset >= x->data.offset &&
                 y->data.offset < x->data.offset + x->type->atomic_size()));
     }
  
     void
     process_atomic_variable(const glsl_type *t, struct gl_shader_program *prog,
                             unsigned *uniform_loc, ir_variable *var,
                             active_atomic_buffer *const buffers,
                             unsigned *num_buffers, int *offset,
                             const unsigned shader_stage)
     {
        /* FIXME: Arrays of arrays get counted separately. For example:
         * x1[3][3][2] = 9 uniforms, 18 atomic counters
         * x2[3][2]    = 3 uniforms, 6 atomic counters
         * x3[2]       = 1 uniform, 2 atomic counters
         *
         * However this code marks all the counters as active even when they
         * might not be used.
         */
        if (t->is_array() && t->fields.array->is_array()) {
           for (unsigned i = 0; i < t->length; i++) {
              process_atomic_variable(t->fields.array, prog, uniform_loc,
                                      var, buffers, num_buffers, offset,
                                      shader_stage);
           }
        } else {
           active_atomic_buffer *buf = &buffers[var->data.binding];
           gl_uniform_storage *const storage =
              &prog->data->UniformStorage[*uniform_loc];
  
           /* If this is the first time the buffer is used, increment
            * the counter of buffers used.
            */
           if (buf->size == 0)
              (*num_buffers)++;
  
           buf->push_back(*uniform_loc, var);
  
           /* When checking for atomic counters we should count every member in
            * an array as an atomic counter reference.
            */
           if (t->is_array())
              buf->stage_counter_references[shader_stage] += t->length;
           else
              buf->stage_counter_references[shader_stage]++;
           buf->size = MAX2(buf->size, *offset + t->atomic_size());
  
           storage->offset = *offset;
           *offset += t->atomic_size();
  
           (*uniform_loc)++;
        }
     }
  
     active_atomic_buffer *
     find_active_atomic_counters(struct gl_context *ctx,
                                 struct gl_shader_program *prog,
                                 unsigned *num_buffers)
     {
        active_atomic_buffer *const buffers =
           new active_atomic_buffer[ctx->Const.MaxAtomicBufferBindings];
  
        *num_buffers = 0;
  
        for (unsigned i = 0; i < MESA_SHADER_STAGES; ++i) {
           struct gl_linked_shader *sh = prog->_LinkedShaders[i];
           if (sh == NULL)
              continue;
  
           foreach_in_list(ir_instruction, node, sh->ir) {
              ir_variable *var = node->as_variable();
  
              if (var && var->type->contains_atomic()) {
                 int offset = var->data.offset;
                 unsigned uniform_loc = var->data.location;
                 process_atomic_variable(var->type, prog, &uniform_loc,
                                         var, buffers, num_buffers, &offset, i);
              }
           }
        }
  
        for (unsigned i = 0; i < ctx->Const.MaxAtomicBufferBindings; i++) {
           if (buffers[i].size == 0)
              continue;
  
           qsort(buffers[i].uniforms, buffers[i].num_uniforms,
                 sizeof(active_atomic_counter_uniform),
                 cmp_actives);
  
           for (unsigned j = 1; j < buffers[i].num_uniforms; j++) {
              /* If an overlapping counter found, it must be a reference to the
               * same counter from a different shader stage.
               */
              if (check_atomic_counters_overlap(buffers[i].uniforms[j-1].var,
                                                buffers[i].uniforms[j].var)
                  && strcmp(buffers[i].uniforms[j-1].var->name,
                            buffers[i].uniforms[j].var->name) != 0) {
                 linker_error(prog, "Atomic counter %s declared at offset %d "
                              "which is already in use.",
                              buffers[i].uniforms[j].var->name,
                              buffers[i].uniforms[j].var->data.offset);
              }
           }
        }
        return buffers;
     }
  }
  
  void
  link_assign_atomic_counter_resources(struct gl_context *ctx,
                                       struct gl_shader_program *prog)
  {
     unsigned num_buffers;
     unsigned num_atomic_buffers[MESA_SHADER_STAGES] = {};
     active_atomic_buffer *abs =
        find_active_atomic_counters(ctx, prog, &num_buffers);
  
     prog->data->AtomicBuffers = rzalloc_array(prog->data, gl_active_atomic_buffer,
                                               num_buffers);
     prog->data->NumAtomicBuffers = num_buffers;
  
     unsigned i = 0;
     for (unsigned binding = 0;
          binding < ctx->Const.MaxAtomicBufferBindings;
          binding++) {
  
        /* If the binding was not used, skip.
         */
        if (abs[binding].size == 0)
           continue;
  
        active_atomic_buffer &ab = abs[binding];
        gl_active_atomic_buffer &mab = prog->data->AtomicBuffers[i];
  
        /* Assign buffer-specific fields. */
        mab.Binding = binding;
        mab.MinimumSize = ab.size;
        mab.Uniforms = rzalloc_array(prog->data->AtomicBuffers, GLuint,
                                     ab.num_uniforms);
        mab.NumUniforms = ab.num_uniforms;
  
        /* Assign counter-specific fields. */
        for (unsigned j = 0; j < ab.num_uniforms; j++) {
           ir_variable *const var = ab.uniforms[j].var;
           gl_uniform_storage *const storage =
              &prog->data->UniformStorage[ab.uniforms[j].uniform_loc];
  
           mab.Uniforms[j] = ab.uniforms[j].uniform_loc;
           if (!var->data.explicit_binding)
              var->data.binding = i;
  
           storage->atomic_buffer_index = i;
           storage->offset = var->data.offset;
           storage->array_stride = (var->type->is_array() ?
                                    var->type->without_array()->atomic_size() : 0);
           if (!var->type->is_matrix())
              storage->matrix_stride = 0;
        }
  
        /* Assign stage-specific fields. */
        for (unsigned j = 0; j < MESA_SHADER_STAGES; ++j) {
           if (ab.stage_counter_references[j]) {
              mab.StageReferences[j] = GL_TRUE;
              num_atomic_buffers[j]++;
           } else {
              mab.StageReferences[j] = GL_FALSE;
           }
        }
  
        i++;
     }
  
     /* Store a list pointers to atomic buffers per stage and store the index
      * to the intra-stage buffer list in uniform storage.
      */
     for (unsigned j = 0; j < MESA_SHADER_STAGES; ++j) {
        if (prog->_LinkedShaders[j] && num_atomic_buffers[j] > 0) {
           struct gl_program *gl_prog = prog->_LinkedShaders[j]->Program;
           gl_prog->info.num_abos = num_atomic_buffers[j];
           gl_prog->sh.AtomicBuffers =
              rzalloc_array(gl_prog, gl_active_atomic_buffer *,
                            num_atomic_buffers[j]);
  
           unsigned intra_stage_idx = 0;
           for (unsigned i = 0; i < num_buffers; i++) {
              struct gl_active_atomic_buffer *atomic_buffer =
                 &prog->data->AtomicBuffers[i];
              if (atomic_buffer->StageReferences[j]) {
                 gl_prog->sh.AtomicBuffers[intra_stage_idx] = atomic_buffer;
  
                 for (unsigned u = 0; u < atomic_buffer->NumUniforms; u++) {
                    prog->data->UniformStorage[atomic_buffer->Uniforms[u]].opaque[j].index =
                       intra_stage_idx;
                    prog->data->UniformStorage[atomic_buffer->Uniforms[u]].opaque[j].active =
                       true;
                 }
  
                 intra_stage_idx++;
              }
           }
        }
     }
  
     delete [] abs;
     assert(i == num_buffers);
  }
  
  void
  link_check_atomic_counter_resources(struct gl_context *ctx,
                                      struct gl_shader_program *prog)
  {
     unsigned num_buffers;
     active_atomic_buffer *const abs =
        find_active_atomic_counters(ctx, prog, &num_buffers);
     unsigned atomic_counters[MESA_SHADER_STAGES] = {};
     unsigned atomic_buffers[MESA_SHADER_STAGES] = {};
     unsigned total_atomic_counters = 0;
     unsigned total_atomic_buffers = 0;
  
     /* Sum the required resources.  Note that this counts buffers and
      * counters referenced by several shader stages multiple times
      * against the combined limit -- That's the behavior the spec
      * requires.
      */
     for (unsigned i = 0; i < ctx->Const.MaxAtomicBufferBindings; i++) {
        if (abs[i].size == 0)
           continue;
  
        for (unsigned j = 0; j < MESA_SHADER_STAGES; ++j) {
           const unsigned n = abs[i].stage_counter_references[j];
  
           if (n) {
              atomic_counters[j] += n;
              total_atomic_counters += n;
              atomic_buffers[j]++;
              total_atomic_buffers++;
           }
        }
     }
  
     /* Check that they are within the supported limits. */
     for (unsigned i = 0; i < MESA_SHADER_STAGES; i++) {
        if (atomic_counters[i] > ctx->Const.Program[i].MaxAtomicCounters)
           linker_error(prog, "Too many %s shader atomic counters",
                        _mesa_shader_stage_to_string(i));
  
        if (atomic_buffers[i] > ctx->Const.Program[i].MaxAtomicBuffers)
           linker_error(prog, "Too many %s shader atomic counter buffers",
                        _mesa_shader_stage_to_string(i));
     }
  
     if (total_atomic_counters > ctx->Const.MaxCombinedAtomicCounters)
        linker_error(prog, "Too many combined atomic counters");
  
     if (total_atomic_buffers > ctx->Const.MaxCombinedAtomicBuffers)
        linker_error(prog, "Too many combined atomic buffers");
  
     delete [] abs;
  }
  