text: // Copyright 2012 the V8 project authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #include "src/v8.h"
  
  #if V8_TARGET_ARCH_X87
  
  #include "src/base/bits.h"
  #include "src/bootstrapper.h"
  #include "src/code-stubs.h"
  #include "src/codegen.h"
  #include "src/ic/handler-compiler.h"
  #include "src/ic/ic.h"
  #include "src/isolate.h"
  #include "src/jsregexp.h"
  #include "src/regexp-macro-assembler.h"
  #include "src/runtime.h"
  
  namespace v8 {
  namespace internal {
  
  
  static void InitializeArrayConstructorDescriptor(
      Isolate* isolate, CodeStubDescriptor* descriptor,
      int constant_stack_parameter_count) {
    // register state
    // eax -- number of arguments
    // edi -- function
    // ebx -- allocation site with elements kind
    Address deopt_handler = Runtime::FunctionForId(
        Runtime::kArrayConstructor)->entry;
  
    if (constant_stack_parameter_count == 0) {
      descriptor->Initialize(deopt_handler, constant_stack_parameter_count,
                             JS_FUNCTION_STUB_MODE);
    } else {
      descriptor->Initialize(eax, deopt_handler, constant_stack_parameter_count,
                             JS_FUNCTION_STUB_MODE, PASS_ARGUMENTS);
    }
  }
  
  
  static void InitializeInternalArrayConstructorDescriptor(
      Isolate* isolate, CodeStubDescriptor* descriptor,
      int constant_stack_parameter_count) {
    // register state
    // eax -- number of arguments
    // edi -- constructor function
    Address deopt_handler = Runtime::FunctionForId(
        Runtime::kInternalArrayConstructor)->entry;
  
    if (constant_stack_parameter_count == 0) {
      descriptor->Initialize(deopt_handler, constant_stack_parameter_count,
                             JS_FUNCTION_STUB_MODE);
    } else {
      descriptor->Initialize(eax, deopt_handler, constant_stack_parameter_count,
                             JS_FUNCTION_STUB_MODE, PASS_ARGUMENTS);
    }
  }
  
  
  void ArrayNoArgumentConstructorStub::InitializeDescriptor(
      CodeStubDescriptor* descriptor) {
    InitializeArrayConstructorDescriptor(isolate(), descriptor, 0);
  }
  
  
  void ArraySingleArgumentConstructorStub::InitializeDescriptor(
      CodeStubDescriptor* descriptor) {
    InitializeArrayConstructorDescriptor(isolate(), descriptor, 1);
  }
  
  
  void ArrayNArgumentsConstructorStub::InitializeDescriptor(
      CodeStubDescriptor* descriptor) {
    InitializeArrayConstructorDescriptor(isolate(), descriptor, -1);
  }
  
  
  void InternalArrayNoArgumentConstructorStub::InitializeDescriptor(
      CodeStubDescriptor* descriptor) {
    InitializeInternalArrayConstructorDescriptor(isolate(), descriptor, 0);
  }
  
  
  void InternalArraySingleArgumentConstructorStub::InitializeDescriptor(
      CodeStubDescriptor* descriptor) {
    InitializeInternalArrayConstructorDescriptor(isolate(), descriptor, 1);
  }
  
  
  void InternalArrayNArgumentsConstructorStub::InitializeDescriptor(
      CodeStubDescriptor* descriptor) {
    InitializeInternalArrayConstructorDescriptor(isolate(), descriptor, -1);
  }
  
  
  #define __ ACCESS_MASM(masm)
  
  
  void HydrogenCodeStub::GenerateLightweightMiss(MacroAssembler* masm,
                                                 ExternalReference miss) {
    // Update the static counter each time a new code stub is generated.
    isolate()->counters()->code_stubs()->Increment();
  
    CallInterfaceDescriptor descriptor = GetCallInterfaceDescriptor();
    int param_count = descriptor.GetEnvironmentParameterCount();
    {
      // Call the runtime system in a fresh internal frame.
      FrameScope scope(masm, StackFrame::INTERNAL);
      DCHECK(param_count == 0 ||
             eax.is(descriptor.GetEnvironmentParameterRegister(param_count - 1)));
      // Push arguments
      for (int i = 0; i < param_count; ++i) {
        __ push(descriptor.GetEnvironmentParameterRegister(i));
      }
      __ CallExternalReference(miss, param_count);
    }
  
    __ ret(0);
  }
  
  
  void StoreBufferOverflowStub::Generate(MacroAssembler* masm) {
    // We don't allow a GC during a store buffer overflow so there is no need to
    // store the registers in any particular way, but we do have to store and
    // restore them.
    __ pushad();
    if (save_doubles()) {
      // Save FPU stat in m108byte.
      __ sub(esp, Immediate(108));
      __ fnsave(Operand(esp, 0));
    }
    const int argument_count = 1;
  
    AllowExternalCallThatCantCauseGC scope(masm);
    __ PrepareCallCFunction(argument_count, ecx);
    __ mov(Operand(esp, 0 * kPointerSize),
           Immediate(ExternalReference::isolate_address(isolate())));
    __ CallCFunction(
        ExternalReference::store_buffer_overflow_function(isolate()),
        argument_count);
    if (save_doubles()) {
      // Restore FPU stat in m108byte.
      __ frstor(Operand(esp, 0));
      __ add(esp, Immediate(108));
    }
    __ popad();
    __ ret(0);
  }
  
  
  class FloatingPointHelper : public AllStatic {
   public:
    enum ArgLocation {
      ARGS_ON_STACK,
      ARGS_IN_REGISTERS
    };
  
    // Code pattern for loading a floating point value. Input value must
    // be either a smi or a heap number object (fp value). Requirements:
    // operand in register number. Returns operand as floating point number
    // on FPU stack.
    static void LoadFloatOperand(MacroAssembler* masm, Register number);
  
    // Test if operands are smi or number objects (fp). Requirements:
    // operand_1 in eax, operand_2 in edx; falls through on float
    // operands, jumps to the non_float label otherwise.
    static void CheckFloatOperands(MacroAssembler* masm,
                                   Label* non_float,
                                   Register scratch);
  };
  
  
  void DoubleToIStub::Generate(MacroAssembler* masm) {
    Register input_reg = this->source();
    Register final_result_reg = this->destination();
    DCHECK(is_truncating());
  
    Label check_negative, process_64_bits, done, done_no_stash;
  
    int double_offset = offset();
  
    // Account for return address and saved regs if input is esp.
    if (input_reg.is(esp)) double_offset += 3 * kPointerSize;
  
    MemOperand mantissa_operand(MemOperand(input_reg, double_offset));
    MemOperand exponent_operand(MemOperand(input_reg,
                                           double_offset + kDoubleSize / 2));
  
    Register scratch1;
    {
      Register scratch_candidates[3] = { ebx, edx, edi };
      for (int i = 0; i < 3; i++) {
        scratch1 = scratch_candidates[i];
        if (!final_result_reg.is(scratch1) && !input_reg.is(scratch1)) break;
      }
    }
    // Since we must use ecx for shifts below, use some other register (eax)
    // to calculate the result if ecx is the requested return register.
    Register result_reg = final_result_reg.is(ecx) ? eax : final_result_reg;
    // Save ecx if it isn't the return register and therefore volatile, or if it
    // is the return register, then save the temp register we use in its stead for
    // the result.
    Register save_reg = final_result_reg.is(ecx) ? eax : ecx;
    __ push(scratch1);
    __ push(save_reg);
  
    bool stash_exponent_copy = !input_reg.is(esp);
    __ mov(scratch1, mantissa_operand);
    __ mov(ecx, exponent_operand);
    if (stash_exponent_copy) __ push(ecx);
  
    __ and_(ecx, HeapNumber::kExponentMask);
    __ shr(ecx, HeapNumber::kExponentShift);
    __ lea(result_reg, MemOperand(ecx, -HeapNumber::kExponentBias));
    __ cmp(result_reg, Immediate(HeapNumber::kMantissaBits));
    __ j(below, &process_64_bits);
  
    // Result is entirely in lower 32-bits of mantissa
    int delta = HeapNumber::kExponentBias + Double::kPhysicalSignificandSize;
    __ sub(ecx, Immediate(delta));
    __ xor_(result_reg, result_reg);
    __ cmp(ecx, Immediate(31));
    __ j(above, &done);
    __ shl_cl(scratch1);
    __ jmp(&check_negative);
  
    __ bind(&process_64_bits);
    // Result must be extracted from shifted 32-bit mantissa
    __ sub(ecx, Immediate(delta));
    __ neg(ecx);
    if (stash_exponent_copy) {
      __ mov(result_reg, MemOperand(esp, 0));
    } else {
      __ mov(result_reg, exponent_operand);
    }
    __ and_(result_reg,
            Immediate(static_cast<uint32_t>(Double::kSignificandMask >> 32)));
    __ add(result_reg,
           Immediate(static_cast<uint32_t>(Double::kHiddenBit >> 32)));
    __ shrd(result_reg, scratch1);
    __ shr_cl(result_reg);
    __ test(ecx, Immediate(32));
    {
      Label skip_mov;
      __ j(equal, &skip_mov, Label::kNear);
      __ mov(scratch1, result_reg);
      __ bind(&skip_mov);
    }
  
    // If the double was negative, negate the integer result.
    __ bind(&check_negative);
    __ mov(result_reg, scratch1);
    __ neg(result_reg);
    if (stash_exponent_copy) {
      __ cmp(MemOperand(esp, 0), Immediate(0));
    } else {
      __ cmp(exponent_operand, Immediate(0));
    }
    {
      Label skip_mov;
      __ j(less_equal, &skip_mov, Label::kNear);
      __ mov(result_reg, scratch1);
      __ bind(&skip_mov);
    }
  
    // Restore registers
    __ bind(&done);
    if (stash_exponent_copy) {
      __ add(esp, Immediate(kDoubleSize / 2));
    }
    __ bind(&done_no_stash);
    if (!final_result_reg.is(result_reg)) {
      DCHECK(final_result_reg.is(ecx));
      __ mov(final_result_reg, result_reg);
    }
    __ pop(save_reg);
    __ pop(scratch1);
    __ ret(0);
  }
  
  
  void FloatingPointHelper::LoadFloatOperand(MacroAssembler* masm,
                                             Register number) {
    Label load_smi, done;
  
    __ JumpIfSmi(number, &load_smi, Label::kNear);
    __ fld_d(FieldOperand(number, HeapNumber::kValueOffset));
    __ jmp(&done, Label::kNear);
  
    __ bind(&load_smi);
    __ SmiUntag(number);
    __ push(number);
    __ fild_s(Operand(esp, 0));
    __ pop(number);
  
    __ bind(&done);
  }
  
  
  void FloatingPointHelper::CheckFloatOperands(MacroAssembler* masm,
                                               Label* non_float,
                                               Register scratch) {
    Label test_other, done;
    // Test if both operands are floats or smi -> scratch=k_is_float;
    // Otherwise scratch = k_not_float.
    __ JumpIfSmi(edx, &test_other, Label::kNear);
    __ mov(scratch, FieldOperand(edx, HeapObject::kMapOffset));
    Factory* factory = masm->isolate()->factory();
    __ cmp(scratch, factory->heap_number_map());
    __ j(not_equal, non_float);  // argument in edx is not a number -> NaN
  
    __ bind(&test_other);
    __ JumpIfSmi(eax, &done, Label::kNear);
    __ mov(scratch, FieldOperand(eax, HeapObject::kMapOffset));
    __ cmp(scratch, factory->heap_number_map());
    __ j(not_equal, non_float);  // argument in eax is not a number -> NaN
  
    // Fall-through: Both operands are numbers.
    __ bind(&done);
  }
  
  
  void MathPowStub::Generate(MacroAssembler* masm) {
    // No SSE2 support
    UNREACHABLE();
  }
  
  
  void FunctionPrototypeStub::Generate(MacroAssembler* masm) {
    Label miss;
    Register receiver = LoadDescriptor::ReceiverRegister();
  
    NamedLoadHandlerCompiler::GenerateLoadFunctionPrototype(masm, receiver, eax,
                                                            ebx, &miss);
    __ bind(&miss);
    PropertyAccessCompiler::TailCallBuiltin(
        masm, PropertyAccessCompiler::MissBuiltin(Code::LOAD_IC));
  }
  
  
  void LoadIndexedInterceptorStub::Generate(MacroAssembler* masm) {
    // Return address is on the stack.
    Label slow;
  
    Register receiver = LoadDescriptor::ReceiverRegister();
    Register key = LoadDescriptor::NameRegister();
    Register scratch = eax;
    DCHECK(!scratch.is(receiver) && !scratch.is(key));
  
    // Check that the key is an array index, that is Uint32.
    __ test(key, Immediate(kSmiTagMask | kSmiSignMask));
    __ j(not_zero, &slow);
  
    // Everything is fine, call runtime.
    __ pop(scratch);
    __ push(receiver);  // receiver
    __ push(key);       // key
    __ push(scratch);   // return address
  
    // Perform tail call to the entry.
    ExternalReference ref = ExternalReference(
        IC_Utility(IC::kLoadElementWithInterceptor), masm->isolate());
    __ TailCallExternalReference(ref, 2, 1);
  
    __ bind(&slow);
    PropertyAccessCompiler::TailCallBuiltin(
        masm, PropertyAccessCompiler::MissBuiltin(Code::KEYED_LOAD_IC));
  }
  
  
  void ArgumentsAccessStub::GenerateReadElement(MacroAssembler* masm) {
    // The key is in edx and the parameter count is in eax.
    DCHECK(edx.is(ArgumentsAccessReadDescriptor::index()));
    DCHECK(eax.is(ArgumentsAccessReadDescriptor::parameter_count()));
  
    // The displacement is used for skipping the frame pointer on the
    // stack. It is the offset of the last parameter (if any) relative
    // to the frame pointer.
    static const int kDisplacement = 1 * kPointerSize;
  
    // Check that the key is a smi.
    Label slow;
    __ JumpIfNotSmi(edx, &slow, Label::kNear);
  
    // Check if the calling frame is an arguments adaptor frame.
    Label adaptor;
    __ mov(ebx, Operand(ebp, StandardFrameConstants::kCallerFPOffset));
    __ mov(ecx, Operand(ebx, StandardFrameConstants::kContextOffset));
    __ cmp(ecx, Immediate(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
    __ j(equal, &adaptor, Label::kNear);
  
    // Check index against formal parameters count limit passed in
    // through register eax. Use unsigned comparison to get negative
    // check for free.
    __ cmp(edx, eax);
    __ j(above_equal, &slow, Label::kNear);
  
    // Read the argument from the stack and return it.
    STATIC_ASSERT(kSmiTagSize == 1);
    STATIC_ASSERT(kSmiTag == 0);  // Shifting code depends on these.
    __ lea(ebx, Operand(ebp, eax, times_2, 0));
    __ neg(edx);
    __ mov(eax, Operand(ebx, edx, times_2, kDisplacement));
    __ ret(0);
  
    // Arguments adaptor case: Check index against actual arguments
    // limit found in the arguments adaptor frame. Use unsigned
    // comparison to get negative check for free.
    __ bind(&adaptor);
    __ mov(ecx, Operand(ebx, ArgumentsAdaptorFrameConstants::kLengthOffset));
    __ cmp(edx, ecx);
    __ j(above_equal, &slow, Label::kNear);
  
    // Read the argument from the stack and return it.
    STATIC_ASSERT(kSmiTagSize == 1);
    STATIC_ASSERT(kSmiTag == 0);  // Shifting code depends on these.
    __ lea(ebx, Operand(ebx, ecx, times_2, 0));
    __ neg(edx);
    __ mov(eax, Operand(ebx, edx, times_2, kDisplacement));
    __ ret(0);
  
    // Slow-case: Handle non-smi or out-of-bounds access to arguments
    // by calling the runtime system.
    __ bind(&slow);
    __ pop(ebx);  // Return address.
    __ push(edx);
    __ push(ebx);
    __ TailCallRuntime(Runtime::kGetArgumentsProperty, 1, 1);
  }
  
  
  void ArgumentsAccessStub::GenerateNewSloppySlow(MacroAssembler* masm) {
    // esp[0] : return address
    // esp[4] : number of parameters
    // esp[8] : receiver displacement
    // esp[12] : function
  
    // Check if the calling frame is an arguments adaptor frame.
    Label runtime;
    __ mov(edx, Operand(ebp, StandardFrameConstants::kCallerFPOffset));
    __ mov(ecx, Operand(edx, StandardFrameConstants::kContextOffset));
    __ cmp(ecx, Immediate(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
    __ j(not_equal, &runtime, Label::kNear);
  
    // Patch the arguments.length and the parameters pointer.
    __ mov(ecx, Operand(edx, ArgumentsAdaptorFrameConstants::kLengthOffset));
    __ mov(Operand(esp, 1 * kPointerSize), ecx);
    __ lea(edx, Operand(edx, ecx, times_2,
                StandardFrameConstants::kCallerSPOffset));
    __ mov(Operand(esp, 2 * kPointerSize), edx);
  
    __ bind(&runtime);
    __ TailCallRuntime(Runtime::kNewSloppyArguments, 3, 1);
  }
  
  
  void ArgumentsAccessStub::GenerateNewSloppyFast(MacroAssembler* masm) {
    // esp[0] : return address
    // esp[4] : number of parameters (tagged)
    // esp[8] : receiver displacement
    // esp[12] : function
  
    // ebx = parameter count (tagged)
    __ mov(ebx, Operand(esp, 1 * kPointerSize));
  
    // Check if the calling frame is an arguments adaptor frame.
    // TODO(rossberg): Factor out some of the bits that are shared with the other
    // Generate* functions.
    Label runtime;
    Label adaptor_frame, try_allocate;
    __ mov(edx, Operand(ebp, StandardFrameConstants::kCallerFPOffset));
    __ mov(ecx, Operand(edx, StandardFrameConstants::kContextOffset));
    __ cmp(ecx, Immediate(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
    __ j(equal, &adaptor_frame, Label::kNear);
  
    // No adaptor, parameter count = argument count.
    __ mov(ecx, ebx);
    __ jmp(&try_allocate, Label::kNear);
  
    // We have an adaptor frame. Patch the parameters pointer.
    __ bind(&adaptor_frame);
    __ mov(ecx, Operand(edx, ArgumentsAdaptorFrameConstants::kLengthOffset));
    __ lea(edx, Operand(edx, ecx, times_2,
                        StandardFrameConstants::kCallerSPOffset));
    __ mov(Operand(esp, 2 * kPointerSize), edx);
  
    // ebx = parameter count (tagged)
    // ecx = argument count (smi-tagged)
    // esp[4] = parameter count (tagged)
    // esp[8] = address of receiver argument
    // Compute the mapped parameter count = min(ebx, ecx) in ebx.
    __ cmp(ebx, ecx);
    __ j(less_equal, &try_allocate, Label::kNear);
    __ mov(ebx, ecx);
  
    __ bind(&try_allocate);
  
    // Save mapped parameter count.
    __ push(ebx);
  
    // Compute the sizes of backing store, parameter map, and arguments object.
    // 1. Parameter map, has 2 extra words containing context and backing store.
    const int kParameterMapHeaderSize =
        FixedArray::kHeaderSize + 2 * kPointerSize;
    Label no_parameter_map;
    __ test(ebx, ebx);
    __ j(zero, &no_parameter_map, Label::kNear);
    __ lea(ebx, Operand(ebx, times_2, kParameterMapHeaderSize));
    __ bind(&no_parameter_map);
  
    // 2. Backing store.
    __ lea(ebx, Operand(ebx, ecx, times_2, FixedArray::kHeaderSize));
  
    // 3. Arguments object.
    __ add(ebx, Immediate(Heap::kSloppyArgumentsObjectSize));
  
    // Do the allocation of all three objects in one go.
    __ Allocate(ebx, eax, edx, edi, &runtime, TAG_OBJECT);
  
    // eax = address of new object(s) (tagged)
    // ecx = argument count (smi-tagged)
    // esp[0] = mapped parameter count (tagged)
    // esp[8] = parameter count (tagged)
    // esp[12] = address of receiver argument
    // Get the arguments map from the current native context into edi.
    Label has_mapped_parameters, instantiate;
    __ mov(edi, Operand(esi, Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX)));
    __ mov(edi, FieldOperand(edi, GlobalObject::kNativeContextOffset));
    __ mov(ebx, Operand(esp, 0 * kPointerSize));
    __ test(ebx, ebx);
    __ j(not_zero, &has_mapped_parameters, Label::kNear);
    __ mov(
        edi,
        Operand(edi, Context::SlotOffset(Context::SLOPPY_ARGUMENTS_MAP_INDEX)));
    __ jmp(&instantiate, Label::kNear);
  
    __ bind(&has_mapped_parameters);
    __ mov(
        edi,
        Operand(edi, Context::SlotOffset(Context::ALIASED_ARGUMENTS_MAP_INDEX)));
    __ bind(&instantiate);
  
    // eax = address of new object (tagged)
    // ebx = mapped parameter count (tagged)
    // ecx = argument count (smi-tagged)
    // edi = address of arguments map (tagged)
    // esp[0] = mapped parameter count (tagged)
    // esp[8] = parameter count (tagged)
    // esp[12] = address of receiver argument
    // Copy the JS object part.
    __ mov(FieldOperand(eax, JSObject::kMapOffset), edi);
    __ mov(FieldOperand(eax, JSObject::kPropertiesOffset),
           masm->isolate()->factory()->empty_fixed_array());
    __ mov(FieldOperand(eax, JSObject::kElementsOffset),
           masm->isolate()->factory()->empty_fixed_array());
  
    // Set up the callee in-object property.
    STATIC_ASSERT(Heap::kArgumentsCalleeIndex == 1);
    __ mov(edx, Operand(esp, 4 * kPointerSize));
    __ AssertNotSmi(edx);
    __ mov(FieldOperand(eax, JSObject::kHeaderSize +
                        Heap::kArgumentsCalleeIndex * kPointerSize),
           edx);
  
    // Use the length (smi tagged) and set that as an in-object property too.
    __ AssertSmi(ecx);
    STATIC_ASSERT(Heap::kArgumentsLengthIndex == 0);
    __ mov(FieldOperand(eax, JSObject::kHeaderSize +
                        Heap::kArgumentsLengthIndex * kPointerSize),
           ecx);
  
    // Set up the elements pointer in the allocated arguments object.
    // If we allocated a parameter map, edi will point there, otherwise to the
    // backing store.
    __ lea(edi, Operand(eax, Heap::kSloppyArgumentsObjectSize));
    __ mov(FieldOperand(eax, JSObject::kElementsOffset), edi);
  
    // eax = address of new object (tagged)
    // ebx = mapped parameter count (tagged)
    // ecx = argument count (tagged)
    // edi = address of parameter map or backing store (tagged)
    // esp[0] = mapped parameter count (tagged)
    // esp[8] = parameter count (tagged)
    // esp[12] = address of receiver argument
    // Free a register.
    __ push(eax);
  
    // Initialize parameter map. If there are no mapped arguments, we're done.
    Label skip_parameter_map;
    __ test(ebx, ebx);
    __ j(zero, &skip_parameter_map);
  
    __ mov(FieldOperand(edi, FixedArray::kMapOffset),
           Immediate(isolate()->factory()->sloppy_arguments_elements_map()));
    __ lea(eax, Operand(ebx, reinterpret_cast<intptr_t>(Smi::FromInt(2))));
    __ mov(FieldOperand(edi, FixedArray::kLengthOffset), eax);
    __ mov(FieldOperand(edi, FixedArray::kHeaderSize + 0 * kPointerSize), esi);
    __ lea(eax, Operand(edi, ebx, times_2, kParameterMapHeaderSize));
    __ mov(FieldOperand(edi, FixedArray::kHeaderSize + 1 * kPointerSize), eax);
  
    // Copy the parameter slots and the holes in the arguments.
    // We need to fill in mapped_parameter_count slots. They index the context,
    // where parameters are stored in reverse order, at
    //   MIN_CONTEXT_SLOTS .. MIN_CONTEXT_SLOTS+parameter_count-1
    // The mapped parameter thus need to get indices
    //   MIN_CONTEXT_SLOTS+parameter_count-1 ..
    //       MIN_CONTEXT_SLOTS+parameter_count-mapped_parameter_count
    // We loop from right to left.
    Label parameters_loop, parameters_test;
    __ push(ecx);
    __ mov(eax, Operand(esp, 2 * kPointerSize));
    __ mov(ebx, Immediate(Smi::FromInt(Context::MIN_CONTEXT_SLOTS)));
    __ add(ebx, Operand(esp, 4 * kPointerSize));
    __ sub(ebx, eax);
    __ mov(ecx, isolate()->factory()->the_hole_value());
    __ mov(edx, edi);
    __ lea(edi, Operand(edi, eax, times_2, kParameterMapHeaderSize));
    // eax = loop variable (tagged)
    // ebx = mapping index (tagged)
    // ecx = the hole value
    // edx = address of parameter map (tagged)
    // edi = address of backing store (tagged)
    // esp[0] = argument count (tagged)
    // esp[4] = address of new object (tagged)
    // esp[8] = mapped parameter count (tagged)
    // esp[16] = parameter count (tagged)
    // esp[20] = address of receiver argument
    __ jmp(&parameters_test, Label::kNear);
  
    __ bind(&parameters_loop);
    __ sub(eax, Immediate(Smi::FromInt(1)));
    __ mov(FieldOperand(edx, eax, times_2, kParameterMapHeaderSize), ebx);
    __ mov(FieldOperand(edi, eax, times_2, FixedArray::kHeaderSize), ecx);
    __ add(ebx, Immediate(Smi::FromInt(1)));
    __ bind(&parameters_test);
    __ test(eax, eax);
    __ j(not_zero, &parameters_loop, Label::kNear);
    __ pop(ecx);
  
    __ bind(&skip_parameter_map);
  
    // ecx = argument count (tagged)
    // edi = address of backing store (tagged)
    // esp[0] = address of new object (tagged)
    // esp[4] = mapped parameter count (tagged)
    // esp[12] = parameter count (tagged)
    // esp[16] = address of receiver argument
    // Copy arguments header and remaining slots (if there are any).
    __ mov(FieldOperand(edi, FixedArray::kMapOffset),
           Immediate(isolate()->factory()->fixed_array_map()));
    __ mov(FieldOperand(edi, FixedArray::kLengthOffset), ecx);
  
    Label arguments_loop, arguments_test;
    __ mov(ebx, Operand(esp, 1 * kPointerSize));
    __ mov(edx, Operand(esp, 4 * kPointerSize));
    __ sub(edx, ebx);  // Is there a smarter way to do negative scaling?
    __ sub(edx, ebx);
    __ jmp(&arguments_test, Label::kNear);
  
    __ bind(&arguments_loop);
    __ sub(edx, Immediate(kPointerSize));
    __ mov(eax, Operand(edx, 0));
    __ mov(FieldOperand(edi, ebx, times_2, FixedArray::kHeaderSize), eax);
    __ add(ebx, Immediate(Smi::FromInt(1)));
  
    __ bind(&arguments_test);
    __ cmp(ebx, ecx);
    __ j(less, &arguments_loop, Label::kNear);
  
    // Restore.
    __ pop(eax);  // Address of arguments object.
    __ pop(ebx);  // Parameter count.
  
    // Return and remove the on-stack parameters.
    __ ret(3 * kPointerSize);
  
    // Do the runtime call to allocate the arguments object.
    __ bind(&runtime);
    __ pop(eax);  // Remove saved parameter count.
    __ mov(Operand(esp, 1 * kPointerSize), ecx);  // Patch argument count.
    __ TailCallRuntime(Runtime::kNewSloppyArguments, 3, 1);
  }
  
  
  void ArgumentsAccessStub::GenerateNewStrict(MacroAssembler* masm) {
    // esp[0] : return address
    // esp[4] : number of parameters
    // esp[8] : receiver displacement
    // esp[12] : function
  
    // Check if the calling frame is an arguments adaptor frame.
    Label adaptor_frame, try_allocate, runtime;
    __ mov(edx, Operand(ebp, StandardFrameConstants::kCallerFPOffset));
    __ mov(ecx, Operand(edx, StandardFrameConstants::kContextOffset));
    __ cmp(ecx, Immediate(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
    __ j(equal, &adaptor_frame, Label::kNear);
  
    // Get the length from the frame.
    __ mov(ecx, Operand(esp, 1 * kPointerSize));
    __ jmp(&try_allocate, Label::kNear);
  
    // Patch the arguments.length and the parameters pointer.
    __ bind(&adaptor_frame);
    __ mov(ecx, Operand(edx, ArgumentsAdaptorFrameConstants::kLengthOffset));
    __ mov(Operand(esp, 1 * kPointerSize), ecx);
    __ lea(edx, Operand(edx, ecx, times_2,
                        StandardFrameConstants::kCallerSPOffset));
    __ mov(Operand(esp, 2 * kPointerSize), edx);
  
    // Try the new space allocation. Start out with computing the size of
    // the arguments object and the elements array.
    Label add_arguments_object;
    __ bind(&try_allocate);
    __ test(ecx, ecx);
    __ j(zero, &add_arguments_object, Label::kNear);
    __ lea(ecx, Operand(ecx, times_2, FixedArray::kHeaderSize));
    __ bind(&add_arguments_object);
    __ add(ecx, Immediate(Heap::kStrictArgumentsObjectSize));
  
    // Do the allocation of both objects in one go.
    __ Allocate(ecx, eax, edx, ebx, &runtime, TAG_OBJECT);
  
    // Get the arguments map from the current native context.
    __ mov(edi, Operand(esi, Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX)));
    __ mov(edi, FieldOperand(edi, GlobalObject::kNativeContextOffset));
    const int offset = Context::SlotOffset(Context::STRICT_ARGUMENTS_MAP_INDEX);
    __ mov(edi, Operand(edi, offset));
  
    __ mov(FieldOperand(eax, JSObject::kMapOffset), edi);
    __ mov(FieldOperand(eax, JSObject::kPropertiesOffset),
           masm->isolate()->factory()->empty_fixed_array());
    __ mov(FieldOperand(eax, JSObject::kElementsOffset),
           masm->isolate()->factory()->empty_fixed_array());
  
    // Get the length (smi tagged) and set that as an in-object property too.
    STATIC_ASSERT(Heap::kArgumentsLengthIndex == 0);
    __ mov(ecx, Operand(esp, 1 * kPointerSize));
    __ AssertSmi(ecx);
    __ mov(FieldOperand(eax, JSObject::kHeaderSize +
                        Heap::kArgumentsLengthIndex * kPointerSize),
           ecx);
  
    // If there are no actual arguments, we're done.
    Label done;
    __ test(ecx, ecx);
    __ j(zero, &done, Label::kNear);
  
    // Get the parameters pointer from the stack.
    __ mov(edx, Operand(esp, 2 * kPointerSize));
  
    // Set up the elements pointer in the allocated arguments object and
    // initialize the header in the elements fixed array.
    __ lea(edi, Operand(eax, Heap::kStrictArgumentsObjectSize));
    __ mov(FieldOperand(eax, JSObject::kElementsOffset), edi);
    __ mov(FieldOperand(edi, FixedArray::kMapOffset),
           Immediate(isolate()->factory()->fixed_array_map()));
  
    __ mov(FieldOperand(edi, FixedArray::kLengthOffset), ecx);
    // Untag the length for the loop below.
    __ SmiUntag(ecx);
  
    // Copy the fixed array slots.
    Label loop;
    __ bind(&loop);
    __ mov(ebx, Operand(edx, -1 * kPointerSize));  // Skip receiver.
    __ mov(FieldOperand(edi, FixedArray::kHeaderSize), ebx);
    __ add(edi, Immediate(kPointerSize));
    __ sub(edx, Immediate(kPointerSize));
    __ dec(ecx);
    __ j(not_zero, &loop);
  
    // Return and remove the on-stack parameters.
    __ bind(&done);
    __ ret(3 * kPointerSize);
  
    // Do the runtime call to allocate the arguments object.
    __ bind(&runtime);
    __ TailCallRuntime(Runtime::kNewStrictArguments, 3, 1);
  }
  
  
  void RegExpExecStub::Generate(MacroAssembler* masm) {
    // Just jump directly to runtime if native RegExp is not selected at compile
    // time or if regexp entry in generated code is turned off runtime switch or
    // at compilation.
  #ifdef V8_INTERPRETED_REGEXP
    __ TailCallRuntime(Runtime::kRegExpExecRT, 4, 1);
  #else  // V8_INTERPRETED_REGEXP
  
    // Stack frame on entry.
    //  esp[0]: return address
    //  esp[4]: last_match_info (expected JSArray)
    //  esp[8]: previous index
    //  esp[12]: subject string
    //  esp[16]: JSRegExp object
  
    static const int kLastMatchInfoOffset = 1 * kPointerSize;
    static const int kPreviousIndexOffset = 2 * kPointerSize;
    static const int kSubjectOffset = 3 * kPointerSize;
    static const int kJSRegExpOffset = 4 * kPointerSize;
  
    Label runtime;
    Factory* factory = isolate()->factory();
  
    // Ensure that a RegExp stack is allocated.
    ExternalReference address_of_regexp_stack_memory_address =
        ExternalReference::address_of_regexp_stack_memory_address(isolate());
    ExternalReference address_of_regexp_stack_memory_size =
        ExternalReference::address_of_regexp_stack_memory_size(isolate());
    __ mov(ebx, Operand::StaticVariable(address_of_regexp_stack_memory_size));
    __ test(ebx, ebx);
    __ j(zero, &runtime);
  
    // Check that the first argument is a JSRegExp object.
    __ mov(eax, Operand(esp, kJSRegExpOffset));
    STATIC_ASSERT(kSmiTag == 0);
    __ JumpIfSmi(eax, &runtime);
    __ CmpObjectType(eax, JS_REGEXP_TYPE, ecx);
    __ j(not_equal, &runtime);
  
    // Check that the RegExp has been compiled (data contains a fixed array).
    __ mov(ecx, FieldOperand(eax, JSRegExp::kDataOffset));
    if (FLAG_debug_code) {
      __ test(ecx, Immediate(kSmiTagMask));
      __ Check(not_zero, kUnexpectedTypeForRegExpDataFixedArrayExpected);
      __ CmpObjectType(ecx, FIXED_ARRAY_TYPE, ebx);
      __ Check(equal, kUnexpectedTypeForRegExpDataFixedArrayExpected);
    }
  
    // ecx: RegExp data (FixedArray)
    // Check the type of the RegExp. Only continue if type is JSRegExp::IRREGEXP.
    __ mov(ebx, FieldOperand(ecx, JSRegExp::kDataTagOffset));
    __ cmp(ebx, Immediate(Smi::FromInt(JSRegExp::IRREGEXP)));
    __ j(not_equal, &runtime);
  
    // ecx: RegExp data (FixedArray)
    // Check that the number of captures fit in the static offsets vector buffer.
    __ mov(edx, FieldOperand(ecx, JSRegExp::kIrregexpCaptureCountOffset));
    // Check (number_of_captures + 1) * 2 <= offsets vector size
    // Or          number_of_captures * 2 <= offsets vector size - 2
    // Multiplying by 2 comes for free since edx is smi-tagged.
    STATIC_ASSERT(kSmiTag == 0);
    STATIC_ASSERT(kSmiTagSize + kSmiShiftSize == 1);
    STATIC_ASSERT(Isolate::kJSRegexpStaticOffsetsVectorSize >= 2);
    __ cmp(edx, Isolate::kJSRegexpStaticOffsetsVectorSize - 2);
    __ j(above, &runtime);
  
    // Reset offset for possibly sliced string.
    __ Move(edi, Immediate(0));
    __ mov(eax, Operand(esp, kSubjectOffset));
    __ JumpIfSmi(eax, &runtime);
    __ mov(edx, eax);  // Make a copy of the original subject string.
    __ mov(ebx, FieldOperand(eax, HeapObject::kMapOffset));
    __ movzx_b(ebx, FieldOperand(ebx, Map::kInstanceTypeOffset));
  
    // eax: subject string
    // edx: subject string
    // ebx: subject string instance type
    // ecx: RegExp data (FixedArray)
    // Handle subject string according to its encoding and representation:
    // (1) Sequential two byte?  If yes, go to (9).
    // (2) Sequential one byte?  If yes, go to (6).
    // (3) Anything but sequential or cons?  If yes, go to (7).
    // (4) Cons string.  If the string is flat, replace subject with first string.
    //     Otherwise bailout.
    // (5a) Is subject sequential two byte?  If yes, go to (9).
    // (5b) Is subject external?  If yes, go to (8).
    // (6) One byte sequential.  Load regexp code for one byte.
    // (E) Carry on.
    /// [...]
  
    // Deferred code at the end of the stub:
    // (7) Not a long external string?  If yes, go to (10).
    // (8) External string.  Make it, offset-wise, look like a sequential string.
    // (8a) Is the external string one byte?  If yes, go to (6).
    // (9) Two byte sequential.  Load regexp code for one byte. Go to (E).
    // (10) Short external string or not a string?  If yes, bail out to runtime.
    // (11) Sliced string.  Replace subject with parent. Go to (5a).
  
    Label seq_one_byte_string /* 6 */, seq_two_byte_string /* 9 */,
          external_string /* 8 */, check_underlying /* 5a */,
          not_seq_nor_cons /* 7 */, check_code /* E */,
          not_long_external /* 10 */;
  
    // (1) Sequential two byte?  If yes, go to (9).
    __ and_(ebx, kIsNotStringMask |
                 kStringRepresentationMask |
                 kStringEncodingMask |
                 kShortExternalStringMask);
    STATIC_ASSERT((kStringTag | kSeqStringTag | kTwoByteStringTag) == 0);
    __ j(zero, &seq_two_byte_string);  // Go to (9).
  
    // (2) Sequential one byte?  If yes, go to (6).
    // Any other sequential string must be one byte.
    __ and_(ebx, Immediate(kIsNotStringMask |
                           kStringRepresentationMask |
                           kShortExternalStringMask));
    __ j(zero, &seq_one_byte_string, Label::kNear);  // Go to (6).
  
    // (3) Anything but sequential or cons?  If yes, go to (7).
    // We check whether the subject string is a cons, since sequential strings
    // have already been covered.
    STATIC_ASSERT(kConsStringTag < kExternalStringTag);
    STATIC_ASSERT(kSlicedStringTag > kExternalStringTag);
    STATIC_ASSERT(kIsNotStringMask > kExternalStringTag);
    STATIC_ASSERT(kShortExternalStringTag > kExternalStringTag);
    __ cmp(ebx, Immediate(kExternalStringTag));
    __ j(greater_equal, &not_seq_nor_cons);  // Go to (7).
  
    // (4) Cons string.  Check that it's flat.
    // Replace subject with first string and reload instance type.
    __ cmp(FieldOperand(eax, ConsString::kSecondOffset), factory->empty_string());
    __ j(not_equal, &runtime);
    __ mov(eax, FieldOperand(eax, ConsString::kFirstOffset));
    __ bind(&check_underlying);
    __ mov(ebx, FieldOperand(eax, HeapObject::kMapOffset));
    __ mov(ebx, FieldOperand(ebx, Map::kInstanceTypeOffset));
  
    // (5a) Is subject sequential two byte?  If yes, go to (9).
    __ test_b(ebx, kStringRepresentationMask | kStringEncodingMask);
    STATIC_ASSERT((kSeqStringTag | kTwoByteStringTag) == 0);
    __ j(zero, &seq_two_byte_string);  // Go to (9).
    // (5b) Is subject external?  If yes, go to (8).
    __ test_b(ebx, kStringRepresentationMask);
    // The underlying external string is never a short external string.
    STATIC_ASSERT(ExternalString::kMaxShortLength < ConsString::kMinLength);
    STATIC_ASSERT(ExternalString::kMaxShortLength < SlicedString::kMinLength);
    __ j(not_zero, &external_string);  // Go to (8).
  
    // eax: sequential subject string (or look-alike, external string)
    // edx: original subject string
    // ecx: RegExp data (FixedArray)
    // (6) One byte sequential.  Load regexp code for one byte.
    __ bind(&seq_one_byte_string);
    // Load previous index and check range before edx is overwritten.  We have
    // to use edx instead of eax here because it might have been only made to
    // look like a sequential string when it actually is an external string.
    __ mov(ebx, Operand(esp, kPreviousIndexOffset));
    __ JumpIfNotSmi(ebx, &runtime);
    __ cmp(ebx, FieldOperand(edx, String::kLengthOffset));
    __ j(above_equal, &runtime);
    __ mov(edx, FieldOperand(ecx, JSRegExp::kDataOneByteCodeOffset));
    __ Move(ecx, Immediate(1));  // Type is one byte.
  
    // (E) Carry on.  String handling is done.
    __ bind(&check_code);
    // edx: irregexp code
    // Check that the irregexp code has been generated for the actual string
    // encoding. If it has, the field contains a code object otherwise it contains
    // a smi (code flushing support).
    __ JumpIfSmi(edx, &runtime);
  
    // eax: subject string
    // ebx: previous index (smi)
    // edx: code
    // ecx: encoding of subject string (1 if one_byte, 0 if two_byte);
    // All checks done. Now push arguments for native regexp code.
    Counters* counters = isolate()->counters();
    __ IncrementCounter(counters->regexp_entry_native(), 1);
  
    // Isolates: note we add an additional parameter here (isolate pointer).
    static const int kRegExpExecuteArguments = 9;
    __ EnterApiExitFrame(kRegExpExecuteArguments);
  
    // Argument 9: Pass current isolate address.
    __ mov(Operand(esp, 8 * kPointerSize),
        Immediate(ExternalReference::isolate_address(isolate())));
  
    // Argument 8: Indicate that this is a direct call from JavaScript.
    __ mov(Operand(esp, 7 * kPointerSize), Immediate(1));
  
    // Argument 7: Start (high end) of backtracking stack memory area.
    __ mov(esi, Operand::StaticVariable(address_of_regexp_stack_memory_address));
    __ add(esi, Operand::StaticVariable(address_of_regexp_stack_memory_size));
    __ mov(Operand(esp, 6 * kPointerSize), esi);
  
    // Argument 6: Set the number of capture registers to zero to force global
    // regexps to behave as non-global.  This does not affect non-global regexps.
    __ mov(Operand(esp, 5 * kPointerSize), Immediate(0));
  
    // Argument 5: static offsets vector buffer.
    __ mov(Operand(esp, 4 * kPointerSize),
           Immediate(ExternalReference::address_of_static_offsets_vector(
               isolate())));
  
    // Argument 2: Previous index.
    __ SmiUntag(ebx);
    __ mov(Operand(esp, 1 * kPointerSize), ebx);
  
    // Argument 1: Original subject string.
    // The original subject is in the previous stack frame. Therefore we have to
    // use ebp, which points exactly to one pointer size below the previous esp.
    // (Because creating a new stack frame pushes the previous ebp onto the stack
    // and thereby moves up esp by one kPointerSize.)
    __ mov(esi, Operand(ebp, kSubjectOffset + kPointerSize));
    __ mov(Operand(esp, 0 * kPointerSize), esi);
  
    // esi: original subject string
    // eax: underlying subject string
    // ebx: previous index
    // ecx: encoding of subject string (1 if one_byte 0 if two_byte);
    // edx: code
    // Argument 4: End of string data
    // Argument 3: Start of string data
    // Prepare start and end index of the input.
    // Load the length from the original sliced string if that is the case.
    __ mov(esi, FieldOperand(esi, String::kLengthOffset));
    __ add(esi, edi);  // Calculate input end wrt offset.
    __ SmiUntag(edi);
    __ add(ebx, edi);  // Calculate input start wrt offset.
  
    // ebx: start index of the input string
    // esi: end index of the input string
    Label setup_two_byte, setup_rest;
    __ test(ecx, ecx);
    __ j(zero, &setup_two_byte, Label::kNear);
    __ SmiUntag(esi);
    __ lea(ecx, FieldOperand(eax, esi, times_1, SeqOneByteString::kHeaderSize));
    __ mov(Operand(esp, 3 * kPointerSize), ecx);  // Argument 4.
    __ lea(ecx, FieldOperand(eax, ebx, times_1, SeqOneByteString::kHeaderSize));
    __ mov(Operand(esp, 2 * kPointerSize), ecx);  // Argument 3.
    __ jmp(&setup_rest, Label::kNear);
  
    __ bind(&setup_two_byte);
    STATIC_ASSERT(kSmiTag == 0);
    STATIC_ASSERT(kSmiTagSize == 1);  // esi is smi (powered by 2).
    __ lea(ecx, FieldOperand(eax, esi, times_1, SeqTwoByteString::kHeaderSize));
    __ mov(Operand(esp, 3 * kPointerSize), ecx);  // Argument 4.
    __ lea(ecx, FieldOperand(eax, ebx, times_2, SeqTwoByteString::kHeaderSize));
    __ mov(Operand(esp, 2 * kPointerSize), ecx);  // Argument 3.
  
    __ bind(&setup_rest);
  
    // Locate the code entry and call it.
    __ add(edx, Immediate(Code::kHeaderSize - kHeapObjectTag));
    __ call(edx);
  
    // Drop arguments and come back to JS mode.
    __ LeaveApiExitFrame(true);
  
    // Check the result.
    Label success;
    __ cmp(eax, 1);
    // We expect exactly one result since we force the called regexp to behave
    // as non-global.
    __ j(equal, &success);
    Label failure;
    __ cmp(eax, NativeRegExpMacroAssembler::FAILURE);
    __ j(equal, &failure);
    __ cmp(eax, NativeRegExpMacroAssembler::EXCEPTION);
    // If not exception it can only be retry. Handle that in the runtime system.
    __ j(not_equal, &runtime);
    // Result must now be exception. If there is no pending exception already a
    // stack overflow (on the backtrack stack) was detected in RegExp code but
    // haven't created the exception yet. Handle that in the runtime system.
    // TODO(592): Rerunning the RegExp to get the stack overflow exception.
    ExternalReference pending_exception(Isolate::kPendingExceptionAddress,
                                        isolate());
    __ mov(edx, Immediate(isolate()->factory()->the_hole_value()));
    __ mov(eax, Operand::StaticVariable(pending_exception));
    __ cmp(edx, eax);
    __ j(equal, &runtime);
    // For exception, throw the exception again.
  
    // Clear the pending exception variable.
    __ mov(Operand::StaticVariable(pending_exception), edx);
  
    // Special handling of termination exceptions which are uncatchable
    // by javascript code.
    __ cmp(eax, factory->termination_exception());
    Label throw_termination_exception;
    __ j(equal, &throw_termination_exception, Label::kNear);
  
    // Handle normal exception by following handler chain.
    __ Throw(eax);
  
    __ bind(&throw_termination_exception);
    __ ThrowUncatchable(eax);
  
    __ bind(&failure);
    // For failure to match, return null.
    __ mov(eax, factory->null_value());
    __ ret(4 * kPointerSize);
  
    // Load RegExp data.
    __ bind(&success);
    __ mov(eax, Operand(esp, kJSRegExpOffset));
    __ mov(ecx, FieldOperand(eax, JSRegExp::kDataOffset));
    __ mov(edx, FieldOperand(ecx, JSRegExp::kIrregexpCaptureCountOffset));
    // Calculate number of capture registers (number_of_captures + 1) * 2.
    STATIC_ASSERT(kSmiTag == 0);
    STATIC_ASSERT(kSmiTagSize + kSmiShiftSize == 1);
    __ add(edx, Immediate(2));  // edx was a smi.
  
    // edx: Number of capture registers
    // Load last_match_info which is still known to be a fast case JSArray.
    // Check that the fourth object is a JSArray object.
    __ mov(eax, Operand(esp, kLastMatchInfoOffset));
    __ JumpIfSmi(eax, &runtime);
    __ CmpObjectType(eax, JS_ARRAY_TYPE, ebx);
    __ j(not_equal, &runtime);
    // Check that the JSArray is in fast case.
    __ mov(ebx, FieldOperand(eax, JSArray::kElementsOffset));
    __ mov(eax, FieldOperand(ebx, HeapObject::kMapOffset));
    __ cmp(eax, factory->fixed_array_map());
    __ j(not_equal, &runtime);
    // Check that the last match info has space for the capture registers and the
    // additional information.
    __ mov(eax, FieldOperand(ebx, FixedArray::kLengthOffset));
    __ SmiUntag(eax);
    __ sub(eax, Immediate(RegExpImpl::kLastMatchOverhead));
    __ cmp(edx, eax);
    __ j(greater, &runtime);
  
    // ebx: last_match_info backing store (FixedArray)
    // edx: number of capture registers
    // Store the capture count.
    __ SmiTag(edx);  // Number of capture registers to smi.
    __ mov(FieldOperand(ebx, RegExpImpl::kLastCaptureCountOffset), edx);
    __ SmiUntag(edx);  // Number of capture registers back from smi.
    // Store last subject and last input.
    __ mov(eax, Operand(esp, kSubjectOffset));
    __ mov(ecx, eax);
    __ mov(FieldOperand(ebx, RegExpImpl::kLastSubjectOffset), eax);
    __ RecordWriteField(ebx, RegExpImpl::kLastSubjectOffset, eax, edi,
                        kDontSaveFPRegs);
    __ mov(eax, ecx);
    __ mov(FieldOperand(ebx, RegExpImpl::kLastInputOffset), eax);
    __ RecordWriteField(ebx, RegExpImpl::kLastInputOffset, eax, edi,
                        kDontSaveFPRegs);
  
    // Get the static offsets vector filled by the native regexp code.
    ExternalReference address_of_static_offsets_vector =
        ExternalReference::address_of_static_offsets_vector(isolate());
    __ mov(ecx, Immediate(address_of_static_offsets_vector));
  
    // ebx: last_match_info backing store (FixedArray)
    // ecx: offsets vector
    // edx: number of capture registers
    Label next_capture, done;
    // Capture register counter starts from number of capture registers and
    // counts down until wraping after zero.
    __ bind(&next_capture);
    __ sub(edx, Immediate(1));
    __ j(negative, &done, Label::kNear);
    // Read the value from the static offsets vector buffer.
    __ mov(edi, Operand(ecx, edx, times_int_size, 0));
    __ SmiTag(edi);
    // Store the smi value in the last match info.
    __ mov(FieldOperand(ebx,
                        edx,
                        times_pointer_size,
                        RegExpImpl::kFirstCaptureOffset),
                        edi);
    __ jmp(&next_capture);
    __ bind(&done);
  
    // Return last match info.
    __ mov(eax, Operand(esp, kLastMatchInfoOffset));
    __ ret(4 * kPointerSize);
  
    // Do the runtime call to execute the regexp.
    __ bind(&runtime);
    __ TailCallRuntime(Runtime::kRegExpExecRT, 4, 1);
  
    // Deferred code for string handling.
    // (7) Not a long external string?  If yes, go to (10).
    __ bind(&not_seq_nor_cons);
    // Compare flags are still set from (3).
    __ j(greater, &not_long_external, Label::kNear);  // Go to (10).
  
    // (8) External string.  Short external strings have been ruled out.
    __ bind(&external_string);
    // Reload instance type.
    __ mov(ebx, FieldOperand(eax, HeapObject::kMapOffset));
    __ movzx_b(ebx, FieldOperand(ebx, Map::kInstanceTypeOffset));
    if (FLAG_debug_code) {
      // Assert that we do not have a cons or slice (indirect strings) here.
      // Sequential strings have already been ruled out.
      __ test_b(ebx, kIsIndirectStringMask);
      __ Assert(zero, kExternalStringExpectedButNotFound);
    }
    __ mov(eax, FieldOperand(eax, ExternalString::kResourceDataOffset));
    // Move the pointer so that offset-wise, it looks like a sequential string.
    STATIC_ASSERT(SeqTwoByteString::kHeaderSize == SeqOneByteString::kHeaderSize);
    __ sub(eax, Immediate(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
    STATIC_ASSERT(kTwoByteStringTag == 0);
    // (8a) Is the external string one byte?  If yes, go to (6).
    __ test_b(ebx, kStringEncodingMask);
    __ j(not_zero, &seq_one_byte_string);  // Goto (6).
  
    // eax: sequential subject string (or look-alike, external string)
    // edx: original subject string
    // ecx: RegExp data (FixedArray)
    // (9) Two byte sequential.  Load regexp code for one byte. Go to (E).
    __ bind(&seq_two_byte_string);
    // Load previous index and check range before edx is overwritten.  We have
    // to use edx instead of eax here because it might have been only made to
    // look like a sequential string when it actually is an external string.
    __ mov(ebx, Operand(esp, kPreviousIndexOffset));
    __ JumpIfNotSmi(ebx, &runtime);
    __ cmp(ebx, FieldOperand(edx, String::kLengthOffset));
    __ j(above_equal, &runtime);
    __ mov(edx, FieldOperand(ecx, JSRegExp::kDataUC16CodeOffset));
    __ Move(ecx, Immediate(0));  // Type is two byte.
    __ jmp(&check_code);  // Go to (E).
  
    // (10) Not a string or a short external string?  If yes, bail out to runtime.
    __ bind(&not_long_external);
    // Catch non-string subject or short external string.
    STATIC_ASSERT(kNotStringTag != 0 && kShortExternalStringTag !=0);
    __ test(ebx, Immediate(kIsNotStringMask | kShortExternalStringTag));
    __ j(not_zero, &runtime);
  
    // (11) Sliced string.  Replace subject with parent.  Go to (5a).
    // Load offset into edi and replace subject string with parent.
    __ mov(edi, FieldOperand(eax, SlicedString::kOffsetOffset));
    __ mov(eax, FieldOperand(eax, SlicedString::kParentOffset));
    __ jmp(&check_underlying);  // Go to (5a).
  #endif  // V8_INTERPRETED_REGEXP
  }
  
  
  static int NegativeComparisonResult(Condition cc) {
    DCHECK(cc != equal);
    DCHECK((cc == less) || (cc == less_equal)
        || (cc == greater) || (cc == greater_equal));
    return (cc == greater || cc == greater_equal) ? LESS : GREATER;
  }
  
  
  static void CheckInputType(MacroAssembler* masm, Register input,
                             CompareICState::State expected, Label* fail) {
    Label ok;
    if (expected == CompareICState::SMI) {
      __ JumpIfNotSmi(input, fail);
    } else if (expected == CompareICState::NUMBER) {
      __ JumpIfSmi(input, &ok);
      __ cmp(FieldOperand(input, HeapObject::kMapOffset),
             Immediate(masm->isolate()->factory()->heap_number_map()));
      __ j(not_equal, fail);
    }
    // We could be strict about internalized/non-internalized here, but as long as
    // hydrogen doesn't care, the stub doesn't have to care either.
    __ bind(&ok);
  }
  
  
  static void BranchIfNotInternalizedString(MacroAssembler* masm,
                                            Label* label,
                                            Register object,
                                            Register scratch) {
    __ JumpIfSmi(object, label);
    __ mov(scratch, FieldOperand(object, HeapObject::kMapOffset));
    __ movzx_b(scratch, FieldOperand(scratch, Map::kInstanceTypeOffset));
    STATIC_ASSERT(kInternalizedTag == 0 && kStringTag == 0);
    __ test(scratch, Immediate(kIsNotStringMask | kIsNotInternalizedMask));
    __ j(not_zero, label);
  }
  
  
  void CompareICStub::GenerateGeneric(MacroAssembler* masm) {
    Label check_unequal_objects;
    Condition cc = GetCondition();
  
    Label miss;
    CheckInputType(masm, edx, left(), &miss);
    CheckInputType(masm, eax, right(), &miss);
  
    // Compare two smis.
    Label non_smi, smi_done;
    __ mov(ecx, edx);
    __ or_(ecx, eax);
    __ JumpIfNotSmi(ecx, &non_smi, Label::kNear);
    __ sub(edx, eax);  // Return on the result of the subtraction.
    __ j(no_overflow, &smi_done, Label::kNear);
    __ not_(edx);  // Correct sign in case of overflow. edx is never 0 here.
    __ bind(&smi_done);
    __ mov(eax, edx);
    __ ret(0);
    __ bind(&non_smi);
  
    // NOTICE! This code is only reached after a smi-fast-case check, so
    // it is certain that at least one operand isn't a smi.
  
    // Identical objects can be compared fast, but there are some tricky cases
    // for NaN and undefined.
    Label generic_heap_number_comparison;
    {
      Label not_identical;
      __ cmp(eax, edx);
      __ j(not_equal, &not_identical);
  
      if (cc != equal) {
        // Check for undefined.  undefined OP undefined is false even though
        // undefined == undefined.
        Label check_for_nan;
        __ cmp(edx, isolate()->factory()->undefined_value());
        __ j(not_equal, &check_for_nan, Label::kNear);
        __ Move(eax, Immediate(Smi::FromInt(NegativeComparisonResult(cc))));
        __ ret(0);
        __ bind(&check_for_nan);
      }
  
      // Test for NaN. Compare heap numbers in a general way,
      // to hanlde NaNs correctly.
      __ cmp(FieldOperand(edx, HeapObject::kMapOffset),
             Immediate(isolate()->factory()->heap_number_map()));
      __ j(equal, &generic_heap_number_comparison, Label::kNear);
      if (cc != equal) {
        // Call runtime on identical JSObjects.  Otherwise return equal.
        __ CmpObjectType(eax, FIRST_SPEC_OBJECT_TYPE, ecx);
        __ j(above_equal, &not_identical);
      }
      __ Move(eax, Immediate(Smi::FromInt(EQUAL)));
      __ ret(0);
  
  
      __ bind(&not_identical);
    }
  
    // Strict equality can quickly decide whether objects are equal.
    // Non-strict object equality is slower, so it is handled later in the stub.
    if (cc == equal && strict()) {
      Label slow;  // Fallthrough label.
      Label not_smis;
      // If we're doing a strict equality comparison, we don't have to do
      // type conversion, so we generate code to do fast comparison for objects
      // and oddballs. Non-smi numbers and strings still go through the usual
      // slow-case code.
      // If either is a Smi (we know that not both are), then they can only
      // be equal if the other is a HeapNumber. If so, use the slow case.
      STATIC_ASSERT(kSmiTag == 0);
      DCHECK_EQ(0, Smi::FromInt(0));
      __ mov(ecx, Immediate(kSmiTagMask));
      __ and_(ecx, eax);
      __ test(ecx, edx);
      __ j(not_zero, &not_smis, Label::kNear);
      // One operand is a smi.
  
      // Check whether the non-smi is a heap number.
      STATIC_ASSERT(kSmiTagMask == 1);
      // ecx still holds eax & kSmiTag, which is either zero or one.
      __ sub(ecx, Immediate(0x01));
      __ mov(ebx, edx);
      __ xor_(ebx, eax);
      __ and_(ebx, ecx);  // ebx holds either 0 or eax ^ edx.
      __ xor_(ebx, eax);
      // if eax was smi, ebx is now edx, else eax.
  
      // Check if the non-smi operand is a heap number.
      __ cmp(FieldOperand(ebx, HeapObject::kMapOffset),
             Immediate(isolate()->factory()->heap_number_map()));
      // If heap number, handle it in the slow case.
      __ j(equal, &slow, Label::kNear);
      // Return non-equal (ebx is not zero)
      __ mov(eax, ebx);
      __ ret(0);
  
      __ bind(&not_smis);
      // If either operand is a JSObject or an oddball value, then they are not
      // equal since their pointers are different
      // There is no test for undetectability in strict equality.
  
      // Get the type of the first operand.
      // If the first object is a JS object, we have done pointer comparison.
      Label first_non_object;
      STATIC_ASSERT(LAST_TYPE == LAST_SPEC_OBJECT_TYPE);
      __ CmpObjectType(eax, FIRST_SPEC_OBJECT_TYPE, ecx);
      __ j(below, &first_non_object, Label::kNear);
  
      // Return non-zero (eax is not zero)
      Label return_not_equal;
      STATIC_ASSERT(kHeapObjectTag != 0);
      __ bind(&return_not_equal);
      __ ret(0);
  
      __ bind(&first_non_object);
      // Check for oddballs: true, false, null, undefined.
      __ CmpInstanceType(ecx, ODDBALL_TYPE);
      __ j(equal, &return_not_equal);
  
      __ CmpObjectType(edx, FIRST_SPEC_OBJECT_TYPE, ecx);
      __ j(above_equal, &return_not_equal);
  
      // Check for oddballs: true, false, null, undefined.
      __ CmpInstanceType(ecx, ODDBALL_TYPE);
      __ j(equal, &return_not_equal);
  
      // Fall through to the general case.
      __ bind(&slow);
    }
  
    // Generate the number comparison code.
    Label non_number_comparison;
    Label unordered;
    __ bind(&generic_heap_number_comparison);
    FloatingPointHelper::CheckFloatOperands(
        masm, &non_number_comparison, ebx);
    FloatingPointHelper::LoadFloatOperand(masm, eax);
    FloatingPointHelper::LoadFloatOperand(masm, edx);
    __ FCmp();
  
    // Don't base result on EFLAGS when a NaN is involved.
    __ j(parity_even, &unordered, Label::kNear);
  
    Label below_label, above_label;
    // Return a result of -1, 0, or 1, based on EFLAGS.
    __ j(below, &below_label, Label::kNear);
    __ j(above, &above_label, Label::kNear);
  
    __ Move(eax, Immediate(0));
    __ ret(0);
  
    __ bind(&below_label);
    __ mov(eax, Immediate(Smi::FromInt(-1)));
    __ ret(0);
  
    __ bind(&above_label);
    __ mov(eax, Immediate(Smi::FromInt(1)));
    __ ret(0);
  
    // If one of the numbers was NaN, then the result is always false.
    // The cc is never not-equal.
    __ bind(&unordered);
    DCHECK(cc != not_equal);
    if (cc == less || cc == less_equal) {
      __ mov(eax, Immediate(Smi::FromInt(1)));
    } else {
      __ mov(eax, Immediate(Smi::FromInt(-1)));
    }
    __ ret(0);
  
    // The number comparison code did not provide a valid result.
    __ bind(&non_number_comparison);
  
    // Fast negative check for internalized-to-internalized equality.
    Label check_for_strings;
    if (cc == equal) {
      BranchIfNotInternalizedString(masm, &check_for_strings, eax, ecx);
      BranchIfNotInternalizedString(masm, &check_for_strings, edx, ecx);
  
      // We've already checked for object identity, so if both operands
      // are internalized they aren't equal. Register eax already holds a
      // non-zero value, which indicates not equal, so just return.
      __ ret(0);
    }
  
    __ bind(&check_for_strings);
  
    __ JumpIfNotBothSequentialOneByteStrings(edx, eax, ecx, ebx,
                                             &check_unequal_objects);
  
    // Inline comparison of one-byte strings.
    if (cc == equal) {
      StringHelper::GenerateFlatOneByteStringEquals(masm, edx, eax, ecx, ebx);
    } else {
      StringHelper::GenerateCompareFlatOneByteStrings(masm, edx, eax, ecx, ebx,
                                                      edi);
    }
  #ifdef DEBUG
    __ Abort(kUnexpectedFallThroughFromStringComparison);
  #endif
  
    __ bind(&check_unequal_objects);
    if (cc == equal && !strict()) {
      // Non-strict equality.  Objects are unequal if
      // they are both JSObjects and not undetectable,
      // and their pointers are different.
      Label not_both_objects;
      Label return_unequal;
      // At most one is a smi, so we can test for smi by adding the two.
      // A smi plus a heap object has the low bit set, a heap object plus
      // a heap object has the low bit clear.
      STATIC_ASSERT(kSmiTag == 0);
      STATIC_ASSERT(kSmiTagMask == 1);
      __ lea(ecx, Operand(eax, edx, times_1, 0));
      __ test(ecx, Immediate(kSmiTagMask));
      __ j(not_zero, &not_both_objects, Label::kNear);
      __ CmpObjectType(eax, FIRST_SPEC_OBJECT_TYPE, ecx);
      __ j(below, &not_both_objects, Label::kNear);
      __ CmpObjectType(edx, FIRST_SPEC_OBJECT_TYPE, ebx);
      __ j(below, &not_both_objects, Label::kNear);
      // We do not bail out after this point.  Both are JSObjects, and
      // they are equal if and only if both are undetectable.
      // The and of the undetectable flags is 1 if and only if they are equal.
      __ test_b(FieldOperand(ecx, Map::kBitFieldOffset),
                1 << Map::kIsUndetectable);
      __ j(zero, &return_unequal, Label::kNear);
      __ test_b(FieldOperand(ebx, Map::kBitFieldOffset),
                1 << Map::kIsUndetectable);
      __ j(zero, &return_unequal, Label::kNear);
      // The objects are both undetectable, so they both compare as the value
      // undefined, and are equal.
      __ Move(eax, Immediate(EQUAL));
      __ bind(&return_unequal);
      // Return non-equal by returning the non-zero object pointer in eax,
      // or return equal if we fell through to here.
      __ ret(0);  // rax, rdx were pushed
      __ bind(&not_both_objects);
    }
  
    // Push arguments below the return address.
    __ pop(ecx);
    __ push(edx);
    __ push(eax);
  
    // Figure out which native to call and setup the arguments.
    Builtins::JavaScript builtin;
    if (cc == equal) {
      builtin = strict() ? Builtins::STRICT_EQUALS : Builtins::EQUALS;
    } else {
      builtin = Builtins::COMPARE;
      __ push(Immediate(Smi::FromInt(NegativeComparisonResult(cc))));
    }
  
    // Restore return address on the stack.
    __ push(ecx);
  
    // Call the native; it returns -1 (less), 0 (equal), or 1 (greater)
    // tagged as a small integer.
    __ InvokeBuiltin(builtin, JUMP_FUNCTION);
  
    __ bind(&miss);
    GenerateMiss(masm);
  }
  
  
  static void GenerateRecordCallTarget(MacroAssembler* masm) {
    // Cache the called function in a feedback vector slot.  Cache states
    // are uninitialized, monomorphic (indicated by a JSFunction), and
    // megamorphic.
    // eax : number of arguments to the construct function
    // ebx : Feedback vector
    // edx : slot in feedback vector (Smi)
    // edi : the function to call
    Isolate* isolate = masm->isolate();
    Label initialize, done, miss, megamorphic, not_array_function;
  
    // Load the cache state into ecx.
    __ mov(ecx, FieldOperand(ebx, edx, times_half_pointer_size,
                             FixedArray::kHeaderSize));
  
    // A monomorphic cache hit or an already megamorphic state: invoke the
    // function without changing the state.
    __ cmp(ecx, edi);
    __ j(equal, &done, Label::kFar);
    __ cmp(ecx, Immediate(TypeFeedbackVector::MegamorphicSentinel(isolate)));
    __ j(equal, &done, Label::kFar);
  
    if (!FLAG_pretenuring_call_new) {
      // If we came here, we need to see if we are the array function.
      // If we didn't have a matching function, and we didn't find the megamorph
      // sentinel, then we have in the slot either some other function or an
      // AllocationSite. Do a map check on the object in ecx.
      Handle<Map> allocation_site_map = isolate->factory()->allocation_site_map();
      __ cmp(FieldOperand(ecx, 0), Immediate(allocation_site_map));
      __ j(not_equal, &miss);
  
      // Make sure the function is the Array() function
      __ LoadGlobalFunction(Context::ARRAY_FUNCTION_INDEX, ecx);
      __ cmp(edi, ecx);
      __ j(not_equal, &megamorphic);
      __ jmp(&done, Label::kFar);
    }
  
    __ bind(&miss);
  
    // A monomorphic miss (i.e, here the cache is not uninitialized) goes
    // megamorphic.
    __ cmp(ecx, Immediate(TypeFeedbackVector::UninitializedSentinel(isolate)));
    __ j(equal, &initialize);
    // MegamorphicSentinel is an immortal immovable object (undefined) so no
    // write-barrier is needed.
    __ bind(&megamorphic);
    __ mov(
        FieldOperand(ebx, edx, times_half_pointer_size, FixedArray::kHeaderSize),
        Immediate(TypeFeedbackVector::MegamorphicSentinel(isolate)));
    __ jmp(&done, Label::kFar);
  
    // An uninitialized cache is patched with the function or sentinel to
    // indicate the ElementsKind if function is the Array constructor.
    __ bind(&initialize);
    if (!FLAG_pretenuring_call_new) {
      // Make sure the function is the Array() function
      __ LoadGlobalFunction(Context::ARRAY_FUNCTION_INDEX, ecx);
      __ cmp(edi, ecx);
      __ j(not_equal, &not_array_function);
  
      // The target function is the Array constructor,
      // Create an AllocationSite if we don't already have it, store it in the
      // slot.
      {
        FrameScope scope(masm, StackFrame::INTERNAL);
  
        // Arguments register must be smi-tagged to call out.
        __ SmiTag(eax);
        __ push(eax);
        __ push(edi);
        __ push(edx);
        __ push(ebx);
  
        CreateAllocationSiteStub create_stub(isolate);
        __ CallStub(&create_stub);
  
        __ pop(ebx);
        __ pop(edx);
        __ pop(edi);
        __ pop(eax);
        __ SmiUntag(eax);
      }
      __ jmp(&done);
  
      __ bind(&not_array_function);
    }
  
    __ mov(FieldOperand(ebx, edx, times_half_pointer_size,
                        FixedArray::kHeaderSize),
           edi);
    // We won't need edx or ebx anymore, just save edi
    __ push(edi);
    __ push(ebx);
    __ push(edx);
    __ RecordWriteArray(ebx, edi, edx, kDontSaveFPRegs, EMIT_REMEMBERED_SET,
                        OMIT_SMI_CHECK);
    __ pop(edx);
    __ pop(ebx);
    __ pop(edi);
  
    __ bind(&done);
  }
  
  
  static void EmitContinueIfStrictOrNative(MacroAssembler* masm, Label* cont) {
    // Do not transform the receiver for strict mode functions.
    __ mov(ecx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
    __ test_b(FieldOperand(ecx, SharedFunctionInfo::kStrictModeByteOffset),
              1 << SharedFunctionInfo::kStrictModeBitWithinByte);
    __ j(not_equal, cont);
  
    // Do not transform the receiver for natives (shared already in ecx).
    __ test_b(FieldOperand(ecx, SharedFunctionInfo::kNativeByteOffset),
              1 << SharedFunctionInfo::kNativeBitWithinByte);
    __ j(not_equal, cont);
  }
  
  
  static void EmitSlowCase(Isolate* isolate,
                           MacroAssembler* masm,
                           int argc,
                           Label* non_function) {
    // Check for function proxy.
    __ CmpInstanceType(ecx, JS_FUNCTION_PROXY_TYPE);
    __ j(not_equal, non_function);
    __ pop(ecx);
    __ push(edi);  // put proxy as additional argument under return address
    __ push(ecx);
    __ Move(eax, Immediate(argc + 1));
    __ Move(ebx, Immediate(0));
    __ GetBuiltinEntry(edx, Builtins::CALL_FUNCTION_PROXY);
    {
      Handle<Code> adaptor = isolate->builtins()->ArgumentsAdaptorTrampoline();
      __ jmp(adaptor, RelocInfo::CODE_TARGET);
    }
  
    // CALL_NON_FUNCTION expects the non-function callee as receiver (instead
    // of the original receiver from the call site).
    __ bind(non_function);
    __ mov(Operand(esp, (argc + 1) * kPointerSize), edi);
    __ Move(eax, Immediate(argc));
    __ Move(ebx, Immediate(0));
    __ GetBuiltinEntry(edx, Builtins::CALL_NON_FUNCTION);
    Handle<Code> adaptor = isolate->builtins()->ArgumentsAdaptorTrampoline();
    __ jmp(adaptor, RelocInfo::CODE_TARGET);
  }
  
  
  static void EmitWrapCase(MacroAssembler* masm, int argc, Label* cont) {
    // Wrap the receiver and patch it back onto the stack.
    { FrameScope frame_scope(masm, StackFrame::INTERNAL);
      __ push(edi);
      __ push(eax);
      __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
      __ pop(edi);
    }
    __ mov(Operand(esp, (argc + 1) * kPointerSize), eax);
    __ jmp(cont);
  }
  
  
  static void CallFunctionNoFeedback(MacroAssembler* masm,
                                     int argc, bool needs_checks,
                                     bool call_as_method) {
    // edi : the function to call
    Label slow, non_function, wrap, cont;
  
    if (needs_checks) {
      // Check that the function really is a JavaScript function.
      __ JumpIfSmi(edi, &non_function);
  
      // Goto slow case if we do not have a function.
      __ CmpObjectType(edi, JS_FUNCTION_TYPE, ecx);
      __ j(not_equal, &slow);
    }
  
    // Fast-case: Just invoke the function.
    ParameterCount actual(argc);
  
    if (call_as_method) {
      if (needs_checks) {
        EmitContinueIfStrictOrNative(masm, &cont);
      }
  
      // Load the receiver from the stack.
      __ mov(eax, Operand(esp, (argc + 1) * kPointerSize));
  
      if (needs_checks) {
        __ JumpIfSmi(eax, &wrap);
  
        __ CmpObjectType(eax, FIRST_SPEC_OBJECT_TYPE, ecx);
        __ j(below, &wrap);
      } else {
        __ jmp(&wrap);
      }
  
      __ bind(&cont);
    }
  
    __ InvokeFunction(edi, actual, JUMP_FUNCTION, NullCallWrapper());
  
    if (needs_checks) {
      // Slow-case: Non-function called.
      __ bind(&slow);
      // (non_function is bound in EmitSlowCase)
      EmitSlowCase(masm->isolate(), masm, argc, &non_function);
    }
  
    if (call_as_method) {
      __ bind(&wrap);
      EmitWrapCase(masm, argc, &cont);
    }
  }
  
  
  void CallFunctionStub::Generate(MacroAssembler* masm) {
    CallFunctionNoFeedback(masm, argc(), NeedsChecks(), CallAsMethod());
  }
  
  
  void CallConstructStub::Generate(MacroAssembler* masm) {
    // eax : number of arguments
    // ebx : feedback vector
    // edx : (only if ebx is not the megamorphic symbol) slot in feedback
    //       vector (Smi)
    // edi : constructor function
    Label slow, non_function_call;
  
    // Check that function is not a smi.
    __ JumpIfSmi(edi, &non_function_call);
    // Check that function is a JSFunction.
    __ CmpObjectType(edi, JS_FUNCTION_TYPE, ecx);
    __ j(not_equal, &slow);
  
    if (RecordCallTarget()) {
      GenerateRecordCallTarget(masm);
  
      if (FLAG_pretenuring_call_new) {
        // Put the AllocationSite from the feedback vector into ebx.
        // By adding kPointerSize we encode that we know the AllocationSite
        // entry is at the feedback vector slot given by edx + 1.
        __ mov(ebx, FieldOperand(ebx, edx, times_half_pointer_size,
                                 FixedArray::kHeaderSize + kPointerSize));
      } else {
        Label feedback_register_initialized;
        // Put the AllocationSite from the feedback vector into ebx, or undefined.
        __ mov(ebx, FieldOperand(ebx, edx, times_half_pointer_size,
                                 FixedArray::kHeaderSize));
        Handle<Map> allocation_site_map =
            isolate()->factory()->allocation_site_map();
        __ cmp(FieldOperand(ebx, 0), Immediate(allocation_site_map));
        __ j(equal, &feedback_register_initialized);
        __ mov(ebx, isolate()->factory()->undefined_value());
        __ bind(&feedback_register_initialized);
      }
  
      __ AssertUndefinedOrAllocationSite(ebx);
    }
  
    // Jump to the function-specific construct stub.
    Register jmp_reg = ecx;
    __ mov(jmp_reg, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
    __ mov(jmp_reg, FieldOperand(jmp_reg,
                                 SharedFunctionInfo::kConstructStubOffset));
    __ lea(jmp_reg, FieldOperand(jmp_reg, Code::kHeaderSize));
    __ jmp(jmp_reg);
  
    // edi: called object
    // eax: number of arguments
    // ecx: object map
    Label do_call;
    __ bind(&slow);
    __ CmpInstanceType(ecx, JS_FUNCTION_PROXY_TYPE);
    __ j(not_equal, &non_function_call);
    __ GetBuiltinEntry(edx, Builtins::CALL_FUNCTION_PROXY_AS_CONSTRUCTOR);
    __ jmp(&do_call);
  
    __ bind(&non_function_call);
    __ GetBuiltinEntry(edx, Builtins::CALL_NON_FUNCTION_AS_CONSTRUCTOR);
    __ bind(&do_call);
    // Set expected number of arguments to zero (not changing eax).
    __ Move(ebx, Immediate(0));
    Handle<Code> arguments_adaptor =
        isolate()->builtins()->ArgumentsAdaptorTrampoline();
    __ jmp(arguments_adaptor, RelocInfo::CODE_TARGET);
  }
  
  
  static void EmitLoadTypeFeedbackVector(MacroAssembler* masm, Register vector) {
    __ mov(vector, Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
    __ mov(vector, FieldOperand(vector, JSFunction::kSharedFunctionInfoOffset));
    __ mov(vector, FieldOperand(vector,
                                SharedFunctionInfo::kFeedbackVectorOffset));
  }
  
  
  void CallIC_ArrayStub::Generate(MacroAssembler* masm) {
    // edi - function
    // edx - slot id
    Label miss;
    int argc = arg_count();
    ParameterCount actual(argc);
  
    EmitLoadTypeFeedbackVector(masm, ebx);
  
    __ LoadGlobalFunction(Context::ARRAY_FUNCTION_INDEX, ecx);
    __ cmp(edi, ecx);
    __ j(not_equal, &miss);
  
    __ mov(eax, arg_count());
    __ mov(ecx, FieldOperand(ebx, edx, times_half_pointer_size,
                             FixedArray::kHeaderSize));
  
    // Verify that ecx contains an AllocationSite
    Factory* factory = masm->isolate()->factory();
    __ cmp(FieldOperand(ecx, HeapObject::kMapOffset),
           factory->allocation_site_map());
    __ j(not_equal, &miss);
  
    __ mov(ebx, ecx);
    ArrayConstructorStub stub(masm->isolate(), arg_count());
    __ TailCallStub(&stub);
  
    __ bind(&miss);
    GenerateMiss(masm);
  
    // The slow case, we need this no matter what to complete a call after a miss.
    CallFunctionNoFeedback(masm,
                           arg_count(),
                           true,
                           CallAsMethod());
  
    // Unreachable.
    __ int3();
  }
  
  
  void CallICStub::Generate(MacroAssembler* masm) {
    // edi - function
    // edx - slot id
    Isolate* isolate = masm->isolate();
    Label extra_checks_or_miss, slow_start;
    Label slow, non_function, wrap, cont;
    Label have_js_function;
    int argc = arg_count();
    ParameterCount actual(argc);
  
    EmitLoadTypeFeedbackVector(masm, ebx);
  
    // The checks. First, does edi match the recorded monomorphic target?
    __ cmp(edi, FieldOperand(ebx, edx, times_half_pointer_size,
                             FixedArray::kHeaderSize));
    __ j(not_equal, &extra_checks_or_miss);
  
    __ bind(&have_js_function);
    if (CallAsMethod()) {
      EmitContinueIfStrictOrNative(masm, &cont);
  
      // Load the receiver from the stack.
      __ mov(eax, Operand(esp, (argc + 1) * kPointerSize));
  
      __ JumpIfSmi(eax, &wrap);
  
      __ CmpObjectType(eax, FIRST_SPEC_OBJECT_TYPE, ecx);
      __ j(below, &wrap);
  
      __ bind(&cont);
    }
  
    __ InvokeFunction(edi, actual, JUMP_FUNCTION, NullCallWrapper());
  
    __ bind(&slow);
    EmitSlowCase(isolate, masm, argc, &non_function);
  
    if (CallAsMethod()) {
      __ bind(&wrap);
      EmitWrapCase(masm, argc, &cont);
    }
  
    __ bind(&extra_checks_or_miss);
    Label miss;
  
    __ mov(ecx, FieldOperand(ebx, edx, times_half_pointer_size,
                             FixedArray::kHeaderSize));
    __ cmp(ecx, Immediate(TypeFeedbackVector::MegamorphicSentinel(isolate)));
    __ j(equal, &slow_start);
    __ cmp(ecx, Immediate(TypeFeedbackVector::UninitializedSentinel(isolate)));
    __ j(equal, &miss);
  
    if (!FLAG_trace_ic) {
      // We are going megamorphic. If the feedback is a JSFunction, it is fine
      // to handle it here. More complex cases are dealt with in the runtime.
      __ AssertNotSmi(ecx);
      __ CmpObjectType(ecx, JS_FUNCTION_TYPE, ecx);
      __ j(not_equal, &miss);
      __ mov(FieldOperand(ebx, edx, times_half_pointer_size,
                          FixedArray::kHeaderSize),
             Immediate(TypeFeedbackVector::MegamorphicSentinel(isolate)));
      __ jmp(&slow_start);
    }
  
    // We are here because tracing is on or we are going monomorphic.
    __ bind(&miss);
    GenerateMiss(masm);
  
    // the slow case
    __ bind(&slow_start);
  
    // Check that the function really is a JavaScript function.
    __ JumpIfSmi(edi, &non_function);
  
    // Goto slow case if we do not have a function.
    __ CmpObjectType(edi, JS_FUNCTION_TYPE, ecx);
    __ j(not_equal, &slow);
    __ jmp(&have_js_function);
  
    // Unreachable
    __ int3();
  }
  
  
  void CallICStub::GenerateMiss(MacroAssembler* masm) {
    // Get the receiver of the function from the stack; 1 ~ return address.
    __ mov(ecx, Operand(esp, (arg_count() + 1) * kPointerSize));
  
    {
      FrameScope scope(masm, StackFrame::INTERNAL);
  
      // Push the receiver and the function and feedback info.
      __ push(ecx);
      __ push(edi);
      __ push(ebx);
      __ push(edx);
  
      // Call the entry.
      IC::UtilityId id = GetICState() == DEFAULT ? IC::kCallIC_Miss
                                                 : IC::kCallIC_Customization_Miss;
  
      ExternalReference miss = ExternalReference(IC_Utility(id),
                                                 masm->isolate());
      __ CallExternalReference(miss, 4);
  
      // Move result to edi and exit the internal frame.
      __ mov(edi, eax);
    }
  }
  
  
  bool CEntryStub::NeedsImmovableCode() {
    return false;
  }
  
  
  void CodeStub::GenerateStubsAheadOfTime(Isolate* isolate) {
    CEntryStub::GenerateAheadOfTime(isolate);
    StoreBufferOverflowStub::GenerateFixedRegStubsAheadOfTime(isolate);
    StubFailureTrampolineStub::GenerateAheadOfTime(isolate);
    // It is important that the store buffer overflow stubs are generated first.
    ArrayConstructorStubBase::GenerateStubsAheadOfTime(isolate);
    CreateAllocationSiteStub::GenerateAheadOfTime(isolate);
    BinaryOpICStub::GenerateAheadOfTime(isolate);
    BinaryOpICWithAllocationSiteStub::GenerateAheadOfTime(isolate);
  }
  
  
  void CodeStub::GenerateFPStubs(Isolate* isolate) {
    CEntryStub save_doubles(isolate, 1, kSaveFPRegs);
    // Stubs might already be in the snapshot, detect that and don't regenerate,
    // which would lead to code stub initialization state being messed up.
    Code* save_doubles_code;
    if (!save_doubles.FindCodeInCache(&save_doubles_code)) {
      save_doubles_code = *(save_doubles.GetCode());
    }
    isolate->set_fp_stubs_generated(true);
  }
  
  
  void CEntryStub::GenerateAheadOfTime(Isolate* isolate) {
    CEntryStub stub(isolate, 1, kDontSaveFPRegs);
    stub.GetCode();
  }
  
  
  void CEntryStub::Generate(MacroAssembler* masm) {
    // eax: number of arguments including receiver
    // ebx: pointer to C function  (C callee-saved)
    // ebp: frame pointer  (restored after C call)
    // esp: stack pointer  (restored after C call)
    // esi: current context (C callee-saved)
    // edi: JS function of the caller (C callee-saved)
  
    ProfileEntryHookStub::MaybeCallEntryHook(masm);
  
    // Enter the exit frame that transitions from JavaScript to C++.
    __ EnterExitFrame(save_doubles());
  
    // ebx: pointer to C function  (C callee-saved)
    // ebp: frame pointer  (restored after C call)
    // esp: stack pointer  (restored after C call)
    // edi: number of arguments including receiver  (C callee-saved)
    // esi: pointer to the first argument (C callee-saved)
  
    // Result returned in eax, or eax+edx if result size is 2.
  
    // Check stack alignment.
    if (FLAG_debug_code) {
      __ CheckStackAlignment();
    }
  
    // Call C function.
    __ mov(Operand(esp, 0 * kPointerSize), edi);  // argc.
    __ mov(Operand(esp, 1 * kPointerSize), esi);  // argv.
    __ mov(Operand(esp, 2 * kPointerSize),
           Immediate(ExternalReference::isolate_address(isolate())));
    __ call(ebx);
    // Result is in eax or edx:eax - do not destroy these registers!
  
    // Runtime functions should not return 'the hole'.  Allowing it to escape may
    // lead to crashes in the IC code later.
    if (FLAG_debug_code) {
      Label okay;
      __ cmp(eax, isolate()->factory()->the_hole_value());
      __ j(not_equal, &okay, Label::kNear);
      __ int3();
      __ bind(&okay);
    }
  
    // Check result for exception sentinel.
    Label exception_returned;
    __ cmp(eax, isolate()->factory()->exception());
    __ j(equal, &exception_returned);
  
    ExternalReference pending_exception_address(
        Isolate::kPendingExceptionAddress, isolate());
  
    // Check that there is no pending exception, otherwise we
    // should have returned the exception sentinel.
    if (FLAG_debug_code) {
      __ push(edx);
      __ mov(edx, Immediate(isolate()->factory()->the_hole_value()));
      Label okay;
      __ cmp(edx, Operand::StaticVariable(pending_exception_address));
      // Cannot use check here as it attempts to generate call into runtime.
      __ j(equal, &okay, Label::kNear);
      __ int3();
      __ bind(&okay);
      __ pop(edx);
    }
  
    // Exit the JavaScript to C++ exit frame.
    __ LeaveExitFrame(save_doubles());
    __ ret(0);
  
    // Handling of exception.
    __ bind(&exception_returned);
  
    // Retrieve the pending exception.
    __ mov(eax, Operand::StaticVariable(pending_exception_address));
  
    // Clear the pending exception.
    __ mov(edx, Immediate(isolate()->factory()->the_hole_value()));
    __ mov(Operand::StaticVariable(pending_exception_address), edx);
  
    // Special handling of termination exceptions which are uncatchable
    // by javascript code.
    Label throw_termination_exception;
    __ cmp(eax, isolate()->factory()->termination_exception());
    __ j(equal, &throw_termination_exception);
  
    // Handle normal exception.
    __ Throw(eax);
  
    __ bind(&throw_termination_exception);
    __ ThrowUncatchable(eax);
  }
  
  
  void JSEntryStub::Generate(MacroAssembler* masm) {
    Label invoke, handler_entry, exit;
    Label not_outermost_js, not_outermost_js_2;
  
    ProfileEntryHookStub::MaybeCallEntryHook(masm);
  
    // Set up frame.
    __ push(ebp);
    __ mov(ebp, esp);
  
    // Push marker in two places.
    int marker = type();
    __ push(Immediate(Smi::FromInt(marker)));  // context slot
    __ push(Immediate(Smi::FromInt(marker)));  // function slot
    // Save callee-saved registers (C calling conventions).
    __ push(edi);
    __ push(esi);
    __ push(ebx);
  
    // Save copies of the top frame descriptor on the stack.
    ExternalReference c_entry_fp(Isolate::kCEntryFPAddress, isolate());
    __ push(Operand::StaticVariable(c_entry_fp));
  
    // If this is the outermost JS call, set js_entry_sp value.
    ExternalReference js_entry_sp(Isolate::kJSEntrySPAddress, isolate());
    __ cmp(Operand::StaticVariable(js_entry_sp), Immediate(0));
    __ j(not_equal, &not_outermost_js, Label::kNear);
    __ mov(Operand::StaticVariable(js_entry_sp), ebp);
    __ push(Immediate(Smi::FromInt(StackFrame::OUTERMOST_JSENTRY_FRAME)));
    __ jmp(&invoke, Label::kNear);
    __ bind(&not_outermost_js);
    __ push(Immediate(Smi::FromInt(StackFrame::INNER_JSENTRY_FRAME)));
  
    // Jump to a faked try block that does the invoke, with a faked catch
    // block that sets the pending exception.
    __ jmp(&invoke);
    __ bind(&handler_entry);
    handler_offset_ = handler_entry.pos();
    // Caught exception: Store result (exception) in the pending exception
    // field in the JSEnv and return a failure sentinel.
    ExternalReference pending_exception(Isolate::kPendingExceptionAddress,
                                        isolate());
    __ mov(Operand::StaticVariable(pending_exception), eax);
    __ mov(eax, Immediate(isolate()->factory()->exception()));
    __ jmp(&exit);
  
    // Invoke: Link this frame into the handler chain.  There's only one
    // handler block in this code object, so its index is 0.
    __ bind(&invoke);
    __ PushTryHandler(StackHandler::JS_ENTRY, 0);
  
    // Clear any pending exceptions.
    __ mov(edx, Immediate(isolate()->factory()->the_hole_value()));
    __ mov(Operand::StaticVariable(pending_exception), edx);
  
    // Fake a receiver (NULL).
    __ push(Immediate(0));  // receiver
  
    // Invoke the function by calling through JS entry trampoline builtin and
    // pop the faked function when we return. Notice that we cannot store a
    // reference to the trampoline code directly in this stub, because the
    // builtin stubs may not have been generated yet.
    if (type() == StackFrame::ENTRY_CONSTRUCT) {
      ExternalReference construct_entry(Builtins::kJSConstructEntryTrampoline,
                                        isolate());
      __ mov(edx, Immediate(construct_entry));
    } else {
      ExternalReference entry(Builtins::kJSEntryTrampoline, isolate());
      __ mov(edx, Immediate(entry));
    }
    __ mov(edx, Operand(edx, 0));  // deref address
    __ lea(edx, FieldOperand(edx, Code::kHeaderSize));
    __ call(edx);
  
    // Unlink this frame from the handler chain.
    __ PopTryHandler();
  
    __ bind(&exit);
    // Check if the current stack frame is marked as the outermost JS frame.
    __ pop(ebx);
    __ cmp(ebx, Immediate(Smi::FromInt(StackFrame::OUTERMOST_JSENTRY_FRAME)));
    __ j(not_equal, &not_outermost_js_2);
    __ mov(Operand::StaticVariable(js_entry_sp), Immediate(0));
    __ bind(&not_outermost_js_2);
  
    // Restore the top frame descriptor from the stack.
    __ pop(Operand::StaticVariable(ExternalReference(
        Isolate::kCEntryFPAddress, isolate())));
  
    // Restore callee-saved registers (C calling conventions).
    __ pop(ebx);
    __ pop(esi);
    __ pop(edi);
    __ add(esp, Immediate(2 * kPointerSize));  // remove markers
  
    // Restore frame pointer and return.
    __ pop(ebp);
    __ ret(0);
  }
  
  
  // Generate stub code for instanceof.
  // This code can patch a call site inlined cache of the instance of check,
  // which looks like this.
  //
  //   81 ff XX XX XX XX   cmp    edi, <the hole, patched to a map>
  //   75 0a               jne    <some near label>
  //   b8 XX XX XX XX      mov    eax, <the hole, patched to either true or false>
  //
  // If call site patching is requested the stack will have the delta from the
  // return address to the cmp instruction just below the return address. This
  // also means that call site patching can only take place with arguments in
  // registers. TOS looks like this when call site patching is requested
  //
  //   esp[0] : return address
  //   esp[4] : delta from return address to cmp instruction
  //
  void InstanceofStub::Generate(MacroAssembler* masm) {
    // Call site inlining and patching implies arguments in registers.
    DCHECK(HasArgsInRegisters() || !HasCallSiteInlineCheck());
  
    // Fixed register usage throughout the stub.
    Register object = eax;  // Object (lhs).
    Register map = ebx;  // Map of the object.
    Register function = edx;  // Function (rhs).
    Register prototype = edi;  // Prototype of the function.
    Register scratch = ecx;
  
    // Constants describing the call site code to patch.
    static const int kDeltaToCmpImmediate = 2;
    static const int kDeltaToMov = 8;
    static const int kDeltaToMovImmediate = 9;
    static const int8_t kCmpEdiOperandByte1 = bit_cast<int8_t, uint8_t>(0x3b);
    static const int8_t kCmpEdiOperandByte2 = bit_cast<int8_t, uint8_t>(0x3d);
    static const int8_t kMovEaxImmediateByte = bit_cast<int8_t, uint8_t>(0xb8);
  
    DCHECK_EQ(object.code(), InstanceofStub::left().code());
    DCHECK_EQ(function.code(), InstanceofStub::right().code());
  
    // Get the object and function - they are always both needed.
    Label slow, not_js_object;
    if (!HasArgsInRegisters()) {
      __ mov(object, Operand(esp, 2 * kPointerSize));
      __ mov(function, Operand(esp, 1 * kPointerSize));
    }
  
    // Check that the left hand is a JS object.
    __ JumpIfSmi(object, &not_js_object);
    __ IsObjectJSObjectType(object, map, scratch, &not_js_object);
  
    // If there is a call site cache don't look in the global cache, but do the
    // real lookup and update the call site cache.
    if (!HasCallSiteInlineCheck() && !ReturnTrueFalseObject()) {
      // Look up the function and the map in the instanceof cache.
      Label miss;
      __ CompareRoot(function, scratch, Heap::kInstanceofCacheFunctionRootIndex);
      __ j(not_equal, &miss, Label::kNear);
      __ CompareRoot(map, scratch, Heap::kInstanceofCacheMapRootIndex);
      __ j(not_equal, &miss, Label::kNear);
      __ LoadRoot(eax, Heap::kInstanceofCacheAnswerRootIndex);
      __ ret((HasArgsInRegisters() ? 0 : 2) * kPointerSize);
      __ bind(&miss);
    }
  
    // Get the prototype of the function.
    __ TryGetFunctionPrototype(function, prototype, scratch, &slow, true);
  
    // Check that the function prototype is a JS object.
    __ JumpIfSmi(prototype, &slow);
    __ IsObjectJSObjectType(prototype, scratch, scratch, &slow);
  
    // Update the global instanceof or call site inlined cache with the current
    // map and function. The cached answer will be set when it is known below.
    if (!HasCallSiteInlineCheck()) {
      __ StoreRoot(map, scratch, Heap::kInstanceofCacheMapRootIndex);
      __ StoreRoot(function, scratch, Heap::kInstanceofCacheFunctionRootIndex);
    } else {
      // The constants for the code patching are based on no push instructions
      // at the call site.
      DCHECK(HasArgsInRegisters());
      // Get return address and delta to inlined map check.
      __ mov(scratch, Operand(esp, 0 * kPointerSize));
      __ sub(scratch, Operand(esp, 1 * kPointerSize));
      if (FLAG_debug_code) {
        __ cmpb(Operand(scratch, 0), kCmpEdiOperandByte1);
        __ Assert(equal, kInstanceofStubUnexpectedCallSiteCacheCmp1);
        __ cmpb(Operand(scratch, 1), kCmpEdiOperandByte2);
        __ Assert(equal, kInstanceofStubUnexpectedCallSiteCacheCmp2);
      }
      __ mov(scratch, Operand(scratch, kDeltaToCmpImmediate));
      __ mov(Operand(scratch, 0), map);
    }
  
    // Loop through the prototype chain of the object looking for the function
    // prototype.
    __ mov(scratch, FieldOperand(map, Map::kPrototypeOffset));
    Label loop, is_instance, is_not_instance;
    __ bind(&loop);
    __ cmp(scratch, prototype);
    __ j(equal, &is_instance, Label::kNear);
    Factory* factory = isolate()->factory();
    __ cmp(scratch, Immediate(factory->null_value()));
    __ j(equal, &is_not_instance, Label::kNear);
    __ mov(scratch, FieldOperand(scratch, HeapObject::kMapOffset));
    __ mov(scratch, FieldOperand(scratch, Map::kPrototypeOffset));
    __ jmp(&loop);
  
    __ bind(&is_instance);
    if (!HasCallSiteInlineCheck()) {
      __ mov(eax, Immediate(0));
      __ StoreRoot(eax, scratch, Heap::kInstanceofCacheAnswerRootIndex);
      if (ReturnTrueFalseObject()) {
        __ mov(eax, factory->true_value());
      }
    } else {
      // Get return address and delta to inlined map check.
      __ mov(eax, factory->true_value());
      __ mov(scratch, Operand(esp, 0 * kPointerSize));
      __ sub(scratch, Operand(esp, 1 * kPointerSize));
      if (FLAG_debug_code) {
        __ cmpb(Operand(scratch, kDeltaToMov), kMovEaxImmediateByte);
        __ Assert(equal, kInstanceofStubUnexpectedCallSiteCacheMov);
      }
      __ mov(Operand(scratch, kDeltaToMovImmediate), eax);
      if (!ReturnTrueFalseObject()) {
        __ Move(eax, Immediate(0));
      }
    }
    __ ret((HasArgsInRegisters() ? 0 : 2) * kPointerSize);
  
    __ bind(&is_not_instance);
    if (!HasCallSiteInlineCheck()) {
      __ mov(eax, Immediate(Smi::FromInt(1)));
      __ StoreRoot(eax, scratch, Heap::kInstanceofCacheAnswerRootIndex);
      if (ReturnTrueFalseObject()) {
        __ mov(eax, factory->false_value());
      }
    } else {
      // Get return address and delta to inlined map check.
      __ mov(eax, factory->false_value());
      __ mov(scratch, Operand(esp, 0 * kPointerSize));
      __ sub(scratch, Operand(esp, 1 * kPointerSize));
      if (FLAG_debug_code) {
        __ cmpb(Operand(scratch, kDeltaToMov), kMovEaxImmediateByte);
        __ Assert(equal, kInstanceofStubUnexpectedCallSiteCacheMov);
      }
      __ mov(Operand(scratch, kDeltaToMovImmediate), eax);
      if (!ReturnTrueFalseObject()) {
        __ Move(eax, Immediate(Smi::FromInt(1)));
      }
    }
    __ ret((HasArgsInRegisters() ? 0 : 2) * kPointerSize);
  
    Label object_not_null, object_not_null_or_smi;
    __ bind(&not_js_object);
    // Before null, smi and string value checks, check that the rhs is a function
    // as for a non-function rhs an exception needs to be thrown.
    __ JumpIfSmi(function, &slow, Label::kNear);
    __ CmpObjectType(function, JS_FUNCTION_TYPE, scratch);
    __ j(not_equal, &slow, Label::kNear);
  
    // Null is not instance of anything.
    __ cmp(object, factory->null_value());
    __ j(not_equal, &object_not_null, Label::kNear);
    if (ReturnTrueFalseObject()) {
      __ mov(eax, factory->false_value());
    } else {
      __ Move(eax, Immediate(Smi::FromInt(1)));
    }
    __ ret((HasArgsInRegisters() ? 0 : 2) * kPointerSize);
  
    __ bind(&object_not_null);
    // Smi values is not instance of anything.
    __ JumpIfNotSmi(object, &object_not_null_or_smi, Label::kNear);
    if (ReturnTrueFalseObject()) {
      __ mov(eax, factory->false_value());
    } else {
      __ Move(eax, Immediate(Smi::FromInt(1)));
    }
    __ ret((HasArgsInRegisters() ? 0 : 2) * kPointerSize);
  
    __ bind(&object_not_null_or_smi);
    // String values is not instance of anything.
    Condition is_string = masm->IsObjectStringType(object, scratch, scratch);
    __ j(NegateCondition(is_string), &slow, Label::kNear);
    if (ReturnTrueFalseObject()) {
      __ mov(eax, factory->false_value());
    } else {
      __ Move(eax, Immediate(Smi::FromInt(1)));
    }
    __ ret((HasArgsInRegisters() ? 0 : 2) * kPointerSize);
  
    // Slow-case: Go through the JavaScript implementation.
    __ bind(&slow);
    if (!ReturnTrueFalseObject()) {
      // Tail call the builtin which returns 0 or 1.
      if (HasArgsInRegisters()) {
        // Push arguments below return address.
        __ pop(scratch);
        __ push(object);
        __ push(function);
        __ push(scratch);
      }
      __ InvokeBuiltin(Builtins::INSTANCE_OF, JUMP_FUNCTION);
    } else {
      // Call the builtin and convert 0/1 to true/false.
      {
        FrameScope scope(masm, StackFrame::INTERNAL);
        __ push(object);
        __ push(function);
        __ InvokeBuiltin(Builtins::INSTANCE_OF, CALL_FUNCTION);
      }
      Label true_value, done;
      __ test(eax, eax);
      __ j(zero, &true_value, Label::kNear);
      __ mov(eax, factory->false_value());
      __ jmp(&done, Label::kNear);
      __ bind(&true_value);
      __ mov(eax, factory->true_value());
      __ bind(&done);
      __ ret((HasArgsInRegisters() ? 0 : 2) * kPointerSize);
    }
  }
  
  
  // -------------------------------------------------------------------------
  // StringCharCodeAtGenerator
  
  void StringCharCodeAtGenerator::GenerateFast(MacroAssembler* masm) {
    // If the receiver is a smi trigger the non-string case.
    STATIC_ASSERT(kSmiTag == 0);
    __ JumpIfSmi(object_, receiver_not_string_);
  
    // Fetch the instance type of the receiver into result register.
    __ mov(result_, FieldOperand(object_, HeapObject::kMapOffset));
    __ movzx_b(result_, FieldOperand(result_, Map::kInstanceTypeOffset));
    // If the receiver is not a string trigger the non-string case.
    __ test(result_, Immediate(kIsNotStringMask));
    __ j(not_zero, receiver_not_string_);
  
    // If the index is non-smi trigger the non-smi case.
    STATIC_ASSERT(kSmiTag == 0);
    __ JumpIfNotSmi(index_, &index_not_smi_);
    __ bind(&got_smi_index_);
  
    // Check for index out of range.
    __ cmp(index_, FieldOperand(object_, String::kLengthOffset));
    __ j(above_equal, index_out_of_range_);
  
    __ SmiUntag(index_);
  
    Factory* factory = masm->isolate()->factory();
    StringCharLoadGenerator::Generate(
        masm, factory, object_, index_, result_, &call_runtime_);
  
    __ SmiTag(result_);
    __ bind(&exit_);
  }
  
  
  void StringCharCodeAtGenerator::GenerateSlow(
      MacroAssembler* masm,
      const RuntimeCallHelper& call_helper) {
    __ Abort(kUnexpectedFallthroughToCharCodeAtSlowCase);
  
    // Index is not a smi.
    __ bind(&index_not_smi_);
    // If index is a heap number, try converting it to an integer.
    __ CheckMap(index_,
                masm->isolate()->factory()->heap_number_map(),
                index_not_number_,
                DONT_DO_SMI_CHECK);
    call_helper.BeforeCall(masm);
    __ push(object_);
    __ push(index_);  // Consumed by runtime conversion function.
    if (index_flags_ == STRING_INDEX_IS_NUMBER) {
      __ CallRuntime(Runtime::kNumberToIntegerMapMinusZero, 1);
    } else {
      DCHECK(index_flags_ == STRING_INDEX_IS_ARRAY_INDEX);
      // NumberToSmi discards numbers that are not exact integers.
      __ CallRuntime(Runtime::kNumberToSmi, 1);
    }
    if (!index_.is(eax)) {
      // Save the conversion result before the pop instructions below
      // have a chance to overwrite it.
      __ mov(index_, eax);
    }
    __ pop(object_);
    // Reload the instance type.
    __ mov(result_, FieldOperand(object_, HeapObject::kMapOffset));
    __ movzx_b(result_, FieldOperand(result_, Map::kInstanceTypeOffset));
    call_helper.AfterCall(masm);
    // If index is still not a smi, it must be out of range.
    STATIC_ASSERT(kSmiTag == 0);
    __ JumpIfNotSmi(index_, index_out_of_range_);
    // Otherwise, return to the fast path.
    __ jmp(&got_smi_index_);
  
    // Call runtime. We get here when the receiver is a string and the
    // index is a number, but the code of getting the actual character
    // is too complex (e.g., when the string needs to be flattened).
    __ bind(&call_runtime_);
    call_helper.BeforeCall(masm);
    __ push(object_);
    __ SmiTag(index_);
    __ push(index_);
    __ CallRuntime(Runtime::kStringCharCodeAtRT, 2);
    if (!result_.is(eax)) {
      __ mov(result_, eax);
    }
    call_helper.AfterCall(masm);
    __ jmp(&exit_);
  
    __ Abort(kUnexpectedFallthroughFromCharCodeAtSlowCase);
  }
  
  
  // -------------------------------------------------------------------------
  // StringCharFromCodeGenerator
  
  void StringCharFromCodeGenerator::GenerateFast(MacroAssembler* masm) {
    // Fast case of Heap::LookupSingleCharacterStringFromCode.
    STATIC_ASSERT(kSmiTag == 0);
    STATIC_ASSERT(kSmiShiftSize == 0);
    DCHECK(base::bits::IsPowerOfTwo32(String::kMaxOneByteCharCode + 1));
    __ test(code_,
            Immediate(kSmiTagMask |
                      ((~String::kMaxOneByteCharCode) << kSmiTagSize)));
    __ j(not_zero, &slow_case_);
  
    Factory* factory = masm->isolate()->factory();
    __ Move(result_, Immediate(factory->single_character_string_cache()));
    STATIC_ASSERT(kSmiTag == 0);
    STATIC_ASSERT(kSmiTagSize == 1);
    STATIC_ASSERT(kSmiShiftSize == 0);
    // At this point code register contains smi tagged one byte char code.
    __ mov(result_, FieldOperand(result_,
                                 code_, times_half_pointer_size,
                                 FixedArray::kHeaderSize));
    __ cmp(result_, factory->undefined_value());
    __ j(equal, &slow_case_);
    __ bind(&exit_);
  }
  
  
  void StringCharFromCodeGenerator::GenerateSlow(
      MacroAssembler* masm,
      const RuntimeCallHelper& call_helper) {
    __ Abort(kUnexpectedFallthroughToCharFromCodeSlowCase);
  
    __ bind(&slow_case_);
    call_helper.BeforeCall(masm);
    __ push(code_);
    __ CallRuntime(Runtime::kCharFromCode, 1);
    if (!result_.is(eax)) {
      __ mov(result_, eax);
    }
    call_helper.AfterCall(masm);
    __ jmp(&exit_);
  
    __ Abort(kUnexpectedFallthroughFromCharFromCodeSlowCase);
  }
  
  
  void StringHelper::GenerateCopyCharacters(MacroAssembler* masm,
                                            Register dest,
                                            Register src,
                                            Register count,
                                            Register scratch,
                                            String::Encoding encoding) {
    DCHECK(!scratch.is(dest));
    DCHECK(!scratch.is(src));
    DCHECK(!scratch.is(count));
  
    // Nothing to do for zero characters.
    Label done;
    __ test(count, count);
    __ j(zero, &done);
  
    // Make count the number of bytes to copy.
    if (encoding == String::TWO_BYTE_ENCODING) {
      __ shl(count, 1);
    }
  
    Label loop;
    __ bind(&loop);
    __ mov_b(scratch, Operand(src, 0));
    __ mov_b(Operand(dest, 0), scratch);
    __ inc(src);
    __ inc(dest);
    __ dec(count);
    __ j(not_zero, &loop);
  
    __ bind(&done);
  }
  
  
  void SubStringStub::Generate(MacroAssembler* masm) {
    Label runtime;
  
    // Stack frame on entry.
    //  esp[0]: return address
    //  esp[4]: to
    //  esp[8]: from
    //  esp[12]: string
  
    // Make sure first argument is a string.
    __ mov(eax, Operand(esp, 3 * kPointerSize));
    STATIC_ASSERT(kSmiTag == 0);
    __ JumpIfSmi(eax, &runtime);
    Condition is_string = masm->IsObjectStringType(eax, ebx, ebx);
    __ j(NegateCondition(is_string), &runtime);
  
    // eax: string
    // ebx: instance type
  
    // Calculate length of sub string using the smi values.
    __ mov(ecx, Operand(esp, 1 * kPointerSize));  // To index.
    __ JumpIfNotSmi(ecx, &runtime);
    __ mov(edx, Operand(esp, 2 * kPointerSize));  // From index.
    __ JumpIfNotSmi(edx, &runtime);
    __ sub(ecx, edx);
    __ cmp(ecx, FieldOperand(eax, String::kLengthOffset));
    Label not_original_string;
    // Shorter than original string's length: an actual substring.
    __ j(below, &not_original_string, Label::kNear);
    // Longer than original string's length or negative: unsafe arguments.
    __ j(above, &runtime);
    // Return original string.
    Counters* counters = isolate()->counters();
    __ IncrementCounter(counters->sub_string_native(), 1);
    __ ret(3 * kPointerSize);
    __ bind(&not_original_string);
  
    Label single_char;
    __ cmp(ecx, Immediate(Smi::FromInt(1)));
    __ j(equal, &single_char);
  
    // eax: string
    // ebx: instance type
    // ecx: sub string length (smi)
    // edx: from index (smi)
    // Deal with different string types: update the index if necessary
    // and put the underlying string into edi.
    Label underlying_unpacked, sliced_string, seq_or_external_string;
    // If the string is not indirect, it can only be sequential or external.
    STATIC_ASSERT(kIsIndirectStringMask == (kSlicedStringTag & kConsStringTag));
    STATIC_ASSERT(kIsIndirectStringMask != 0);
    __ test(ebx, Immediate(kIsIndirectStringMask));
    __ j(zero, &seq_or_external_string, Label::kNear);
  
    Factory* factory = isolate()->factory();
    __ test(ebx, Immediate(kSlicedNotConsMask));
    __ j(not_zero, &sliced_string, Label::kNear);
    // Cons string.  Check whether it is flat, then fetch first part.
    // Flat cons strings have an empty second part.
    __ cmp(FieldOperand(eax, ConsString::kSecondOffset),
           factory->empty_string());
    __ j(not_equal, &runtime);
    __ mov(edi, FieldOperand(eax, ConsString::kFirstOffset));
    // Update instance type.
    __ mov(ebx, FieldOperand(edi, HeapObject::kMapOffset));
    __ movzx_b(ebx, FieldOperand(ebx, Map::kInstanceTypeOffset));
    __ jmp(&underlying_unpacked, Label::kNear);
  
    __ bind(&sliced_string);
    // Sliced string.  Fetch parent and adjust start index by offset.
    __ add(edx, FieldOperand(eax, SlicedString::kOffsetOffset));
    __ mov(edi, FieldOperand(eax, SlicedString::kParentOffset));
    // Update instance type.
    __ mov(ebx, FieldOperand(edi, HeapObject::kMapOffset));
    __ movzx_b(ebx, FieldOperand(ebx, Map::kInstanceTypeOffset));
    __ jmp(&underlying_unpacked, Label::kNear);
  
    __ bind(&seq_or_external_string);
    // Sequential or external string.  Just move string to the expected register.
    __ mov(edi, eax);
  
    __ bind(&underlying_unpacked);
  
    if (FLAG_string_slices) {
      Label copy_routine;
      // edi: underlying subject string
      // ebx: instance type of underlying subject string
      // edx: adjusted start index (smi)
      // ecx: length (smi)
      __ cmp(ecx, Immediate(Smi::FromInt(SlicedString::kMinLength)));
      // Short slice.  Copy instead of slicing.
      __ j(less, &copy_routine);
      // Allocate new sliced string.  At this point we do not reload the instance
      // type including the string encoding because we simply rely on the info
      // provided by the original string.  It does not matter if the original
      // string's encoding is wrong because we always have to recheck encoding of
      // the newly created string's parent anyways due to externalized strings.
      Label two_byte_slice, set_slice_header;
      STATIC_ASSERT((kStringEncodingMask & kOneByteStringTag) != 0);
      STATIC_ASSERT((kStringEncodingMask & kTwoByteStringTag) == 0);
      __ test(ebx, Immediate(kStringEncodingMask));
      __ j(zero, &two_byte_slice, Label::kNear);
      __ AllocateOneByteSlicedString(eax, ebx, no_reg, &runtime);
      __ jmp(&set_slice_header, Label::kNear);
      __ bind(&two_byte_slice);
      __ AllocateTwoByteSlicedString(eax, ebx, no_reg, &runtime);
      __ bind(&set_slice_header);
      __ mov(FieldOperand(eax, SlicedString::kLengthOffset), ecx);
      __ mov(FieldOperand(eax, SlicedString::kHashFieldOffset),
             Immediate(String::kEmptyHashField));
      __ mov(FieldOperand(eax, SlicedString::kParentOffset), edi);
      __ mov(FieldOperand(eax, SlicedString::kOffsetOffset), edx);
      __ IncrementCounter(counters->sub_string_native(), 1);
      __ ret(3 * kPointerSize);
  
      __ bind(&copy_routine);
    }
  
    // edi: underlying subject string
    // ebx: instance type of underlying subject string
    // edx: adjusted start index (smi)
    // ecx: length (smi)
    // The subject string can only be external or sequential string of either
    // encoding at this point.
    Label two_byte_sequential, runtime_drop_two, sequential_string;
    STATIC_ASSERT(kExternalStringTag != 0);
    STATIC_ASSERT(kSeqStringTag == 0);
    __ test_b(ebx, kExternalStringTag);
    __ j(zero, &sequential_string);
  
    // Handle external string.
    // Rule out short external strings.
    STATIC_ASSERT(kShortExternalStringTag != 0);
    __ test_b(ebx, kShortExternalStringMask);
    __ j(not_zero, &runtime);
    __ mov(edi, FieldOperand(edi, ExternalString::kResourceDataOffset));
    // Move the pointer so that offset-wise, it looks like a sequential string.
    STATIC_ASSERT(SeqTwoByteString::kHeaderSize == SeqOneByteString::kHeaderSize);
    __ sub(edi, Immediate(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
  
    __ bind(&sequential_string);
    // Stash away (adjusted) index and (underlying) string.
    __ push(edx);
    __ push(edi);
    __ SmiUntag(ecx);
    STATIC_ASSERT((kOneByteStringTag & kStringEncodingMask) != 0);
    __ test_b(ebx, kStringEncodingMask);
    __ j(zero, &two_byte_sequential);
  
    // Sequential one byte string.  Allocate the result.
    __ AllocateOneByteString(eax, ecx, ebx, edx, edi, &runtime_drop_two);
  
    // eax: result string
    // ecx: result string length
    // Locate first character of result.
    __ mov(edi, eax);
    __ add(edi, Immediate(SeqOneByteString::kHeaderSize - kHeapObjectTag));
    // Load string argument and locate character of sub string start.
    __ pop(edx);
    __ pop(ebx);
    __ SmiUntag(ebx);
    __ lea(edx, FieldOperand(edx, ebx, times_1, SeqOneByteString::kHeaderSize));
  
    // eax: result string
    // ecx: result length
    // edi: first character of result
    // edx: character of sub string start
    StringHelper::GenerateCopyCharacters(
        masm, edi, edx, ecx, ebx, String::ONE_BYTE_ENCODING);
    __ IncrementCounter(counters->sub_string_native(), 1);
    __ ret(3 * kPointerSize);
  
    __ bind(&two_byte_sequential);
    // Sequential two-byte string.  Allocate the result.
    __ AllocateTwoByteString(eax, ecx, ebx, edx, edi, &runtime_drop_two);
  
    // eax: result string
    // ecx: result string length
    // Locate first character of result.
    __ mov(edi, eax);
    __ add(edi,
           Immediate(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
    // Load string argument and locate character of sub string start.
    __ pop(edx);
    __ pop(ebx);
    // As from is a smi it is 2 times the value which matches the size of a two
    // byte character.
    STATIC_ASSERT(kSmiTag == 0);
    STATIC_ASSERT(kSmiTagSize + kSmiShiftSize == 1);
    __ lea(edx, FieldOperand(edx, ebx, times_1, SeqTwoByteString::kHeaderSize));
  
    // eax: result string
    // ecx: result length
    // edi: first character of result
    // edx: character of sub string start
    StringHelper::GenerateCopyCharacters(
        masm, edi, edx, ecx, ebx, String::TWO_BYTE_ENCODING);
    __ IncrementCounter(counters->sub_string_native(), 1);
    __ ret(3 * kPointerSize);
  
    // Drop pushed values on the stack before tail call.
    __ bind(&runtime_drop_two);
    __ Drop(2);
  
    // Just jump to runtime to create the sub string.
    __ bind(&runtime);
    __ TailCallRuntime(Runtime::kSubString, 3, 1);
  
    __ bind(&single_char);
    // eax: string
    // ebx: instance type
    // ecx: sub string length (smi)
    // edx: from index (smi)
    StringCharAtGenerator generator(
        eax, edx, ecx, eax, &runtime, &runtime, &runtime, STRING_INDEX_IS_NUMBER);
    generator.GenerateFast(masm);
    __ ret(3 * kPointerSize);
    generator.SkipSlow(masm, &runtime);
  }
  
  
  void StringHelper::GenerateFlatOneByteStringEquals(MacroAssembler* masm,
                                                     Register left,
                                                     Register right,
                                                     Register scratch1,
                                                     Register scratch2) {
    Register length = scratch1;
  
    // Compare lengths.
    Label strings_not_equal, check_zero_length;
    __ mov(length, FieldOperand(left, String::kLengthOffset));
    __ cmp(length, FieldOperand(right, String::kLengthOffset));
    __ j(equal, &check_zero_length, Label::kNear);
    __ bind(&strings_not_equal);
    __ Move(eax, Immediate(Smi::FromInt(NOT_EQUAL)));
    __ ret(0);
  
    // Check if the length is zero.
    Label compare_chars;
    __ bind(&check_zero_length);
    STATIC_ASSERT(kSmiTag == 0);
    __ test(length, length);
    __ j(not_zero, &compare_chars, Label::kNear);
    __ Move(eax, Immediate(Smi::FromInt(EQUAL)));
    __ ret(0);
  
    // Compare characters.
    __ bind(&compare_chars);
    GenerateOneByteCharsCompareLoop(masm, left, right, length, scratch2,
                                    &strings_not_equal, Label::kNear);
  
    // Characters are equal.
    __ Move(eax, Immediate(Smi::FromInt(EQUAL)));
    __ ret(0);
  }
  
  
  void StringHelper::GenerateCompareFlatOneByteStrings(
      MacroAssembler* masm, Register left, Register right, Register scratch1,
      Register scratch2, Register scratch3) {
    Counters* counters = masm->isolate()->counters();
    __ IncrementCounter(counters->string_compare_native(), 1);
  
    // Find minimum length.
    Label left_shorter;
    __ mov(scratch1, FieldOperand(left, String::kLengthOffset));
    __ mov(scratch3, scratch1);
    __ sub(scratch3, FieldOperand(right, String::kLengthOffset));
  
    Register length_delta = scratch3;
  
    __ j(less_equal, &left_shorter, Label::kNear);
    // Right string is shorter. Change scratch1 to be length of right string.
    __ sub(scratch1, length_delta);
    __ bind(&left_shorter);
  
    Register min_length = scratch1;
  
    // If either length is zero, just compare lengths.
    Label compare_lengths;
    __ test(min_length, min_length);
    __ j(zero, &compare_lengths, Label::kNear);
  
    // Compare characters.
    Label result_not_equal;
    GenerateOneByteCharsCompareLoop(masm, left, right, min_length, scratch2,
                                    &result_not_equal, Label::kNear);
  
    // Compare lengths -  strings up to min-length are equal.
    __ bind(&compare_lengths);
    __ test(length_delta, length_delta);
    Label length_not_equal;
    __ j(not_zero, &length_not_equal, Label::kNear);
  
    // Result is EQUAL.
    STATIC_ASSERT(EQUAL == 0);
    STATIC_ASSERT(kSmiTag == 0);
    __ Move(eax, Immediate(Smi::FromInt(EQUAL)));
    __ ret(0);
  
    Label result_greater;
    Label result_less;
    __ bind(&length_not_equal);
    __ j(greater, &result_greater, Label::kNear);
    __ jmp(&result_less, Label::kNear);
    __ bind(&result_not_equal);
    __ j(above, &result_greater, Label::kNear);
    __ bind(&result_less);
  
    // Result is LESS.
    __ Move(eax, Immediate(Smi::FromInt(LESS)));
    __ ret(0);
  
    // Result is GREATER.
    __ bind(&result_greater);
    __ Move(eax, Immediate(Smi::FromInt(GREATER)));
    __ ret(0);
  }
  
  
  void StringHelper::GenerateOneByteCharsCompareLoop(
      MacroAssembler* masm, Register left, Register right, Register length,
      Register scratch, Label* chars_not_equal,
      Label::Distance chars_not_equal_near) {
    // Change index to run from -length to -1 by adding length to string
    // start. This means that loop ends when index reaches zero, which
    // doesn't need an additional compare.
    __ SmiUntag(length);
    __ lea(left,
           FieldOperand(left, length, times_1, SeqOneByteString::kHeaderSize));
    __ lea(right,
           FieldOperand(right, length, times_1, SeqOneByteString::kHeaderSize));
    __ neg(length);
    Register index = length;  // index = -length;
  
    // Compare loop.
    Label loop;
    __ bind(&loop);
    __ mov_b(scratch, Operand(left, index, times_1, 0));
    __ cmpb(scratch, Operand(right, index, times_1, 0));
    __ j(not_equal, chars_not_equal, chars_not_equal_near);
    __ inc(index);
    __ j(not_zero, &loop);
  }
  
  
  void StringCompareStub::Generate(MacroAssembler* masm) {
    Label runtime;
  
    // Stack frame on entry.
    //  esp[0]: return address
    //  esp[4]: right string
    //  esp[8]: left string
  
    __ mov(edx, Operand(esp, 2 * kPointerSize));  // left
    __ mov(eax, Operand(esp, 1 * kPointerSize));  // right
  
    Label not_same;
    __ cmp(edx, eax);
    __ j(not_equal, &not_same, Label::kNear);
    STATIC_ASSERT(EQUAL == 0);
    STATIC_ASSERT(kSmiTag == 0);
    __ Move(eax, Immediate(Smi::FromInt(EQUAL)));
    __ IncrementCounter(isolate()->counters()->string_compare_native(), 1);
    __ ret(2 * kPointerSize);
  
    __ bind(&not_same);
  
    // Check that both objects are sequential one-byte strings.
    __ JumpIfNotBothSequentialOneByteStrings(edx, eax, ecx, ebx, &runtime);
  
    // Compare flat one-byte strings.
    // Drop arguments from the stack.
    __ pop(ecx);
    __ add(esp, Immediate(2 * kPointerSize));
    __ push(ecx);
    StringHelper::GenerateCompareFlatOneByteStrings(masm, edx, eax, ecx, ebx,
                                                    edi);
  
    // Call the runtime; it returns -1 (less), 0 (equal), or 1 (greater)
    // tagged as a small integer.
    __ bind(&runtime);
    __ TailCallRuntime(Runtime::kStringCompare, 2, 1);
  }
  
  
  void BinaryOpICWithAllocationSiteStub::Generate(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- edx    : left
    //  -- eax    : right
    //  -- esp[0] : return address
    // -----------------------------------
  
    // Load ecx with the allocation site.  We stick an undefined dummy value here
    // and replace it with the real allocation site later when we instantiate this
    // stub in BinaryOpICWithAllocationSiteStub::GetCodeCopyFromTemplate().
    __ mov(ecx, handle(isolate()->heap()->undefined_value()));
  
    // Make sure that we actually patched the allocation site.
    if (FLAG_debug_code) {
      __ test(ecx, Immediate(kSmiTagMask));
      __ Assert(not_equal, kExpectedAllocationSite);
      __ cmp(FieldOperand(ecx, HeapObject::kMapOffset),
             isolate()->factory()->allocation_site_map());
      __ Assert(equal, kExpectedAllocationSite);
    }
  
    // Tail call into the stub that handles binary operations with allocation
    // sites.
    BinaryOpWithAllocationSiteStub stub(isolate(), state());
    __ TailCallStub(&stub);
  }
  
  
  void CompareICStub::GenerateSmis(MacroAssembler* masm) {
    DCHECK(state() == CompareICState::SMI);
    Label miss;
    __ mov(ecx, edx);
    __ or_(ecx, eax);
    __ JumpIfNotSmi(ecx, &miss, Label::kNear);
  
    if (GetCondition() == equal) {
      // For equality we do not care about the sign of the result.
      __ sub(eax, edx);
    } else {
      Label done;
      __ sub(edx, eax);
      __ j(no_overflow, &done, Label::kNear);
      // Correct sign of result in case of overflow.
      __ not_(edx);
      __ bind(&done);
      __ mov(eax, edx);
    }
    __ ret(0);
  
    __ bind(&miss);
    GenerateMiss(masm);
  }
  
  
  void CompareICStub::GenerateNumbers(MacroAssembler* masm) {
    DCHECK(state() == CompareICState::NUMBER);
  
    Label generic_stub;
    Label unordered, maybe_undefined1, maybe_undefined2;
    Label miss;
  
    if (left() == CompareICState::SMI) {
      __ JumpIfNotSmi(edx, &miss);
    }
    if (right() == CompareICState::SMI) {
      __ JumpIfNotSmi(eax, &miss);
    }
  
    // Inlining the double comparison and falling back to the general compare
    // stub if NaN is involved or SSE2 or CMOV is unsupported.
    __ mov(ecx, edx);
    __ and_(ecx, eax);
    __ JumpIfSmi(ecx, &generic_stub, Label::kNear);
  
    __ cmp(FieldOperand(eax, HeapObject::kMapOffset),
           isolate()->factory()->heap_number_map());
    __ j(not_equal, &maybe_undefined1, Label::kNear);
    __ cmp(FieldOperand(edx, HeapObject::kMapOffset),
           isolate()->factory()->heap_number_map());
    __ j(not_equal, &maybe_undefined2, Label::kNear);
  
    __ bind(&unordered);
    __ bind(&generic_stub);
    CompareICStub stub(isolate(), op(), CompareICState::GENERIC,
                       CompareICState::GENERIC, CompareICState::GENERIC);
    __ jmp(stub.GetCode(), RelocInfo::CODE_TARGET);
  
    __ bind(&maybe_undefined1);
    if (Token::IsOrderedRelationalCompareOp(op())) {
      __ cmp(eax, Immediate(isolate()->factory()->undefined_value()));
      __ j(not_equal, &miss);
      __ JumpIfSmi(edx, &unordered);
      __ CmpObjectType(edx, HEAP_NUMBER_TYPE, ecx);
      __ j(not_equal, &maybe_undefined2, Label::kNear);
      __ jmp(&unordered);
    }
  
    __ bind(&maybe_undefined2);
    if (Token::IsOrderedRelationalCompareOp(op())) {
      __ cmp(edx, Immediate(isolate()->factory()->undefined_value()));
      __ j(equal, &unordered);
    }
  
    __ bind(&miss);
    GenerateMiss(masm);
  }
  
  
  void CompareICStub::GenerateInternalizedStrings(MacroAssembler* masm) {
    DCHECK(state() == CompareICState::INTERNALIZED_STRING);
    DCHECK(GetCondition() == equal);
  
    // Registers containing left and right operands respectively.
    Register left = edx;
    Register right = eax;
    Register tmp1 = ecx;
    Register tmp2 = ebx;
  
    // Check that both operands are heap objects.
    Label miss;
    __ mov(tmp1, left);
    STATIC_ASSERT(kSmiTag == 0);
    __ and_(tmp1, right);
    __ JumpIfSmi(tmp1, &miss, Label::kNear);
  
    // Check that both operands are internalized strings.
    __ mov(tmp1, FieldOperand(left, HeapObject::kMapOffset));
    __ mov(tmp2, FieldOperand(right, HeapObject::kMapOffset));
    __ movzx_b(tmp1, FieldOperand(tmp1, Map::kInstanceTypeOffset));
    __ movzx_b(tmp2, FieldOperand(tmp2, Map::kInstanceTypeOffset));
    STATIC_ASSERT(kInternalizedTag == 0 && kStringTag == 0);
    __ or_(tmp1, tmp2);
    __ test(tmp1, Immediate(kIsNotStringMask | kIsNotInternalizedMask));
    __ j(not_zero, &miss, Label::kNear);
  
    // Internalized strings are compared by identity.
    Label done;
    __ cmp(left, right);
    // Make sure eax is non-zero. At this point input operands are
    // guaranteed to be non-zero.
    DCHECK(right.is(eax));
    __ j(not_equal, &done, Label::kNear);
    STATIC_ASSERT(EQUAL == 0);
    STATIC_ASSERT(kSmiTag == 0);
    __ Move(eax, Immediate(Smi::FromInt(EQUAL)));
    __ bind(&done);
    __ ret(0);
  
    __ bind(&miss);
    GenerateMiss(masm);
  }
  
  
  void CompareICStub::GenerateUniqueNames(MacroAssembler* masm) {
    DCHECK(state() == CompareICState::UNIQUE_NAME);
    DCHECK(GetCondition() == equal);
  
    // Registers containing left and right operands respectively.
    Register left = edx;
    Register right = eax;
    Register tmp1 = ecx;
    Register tmp2 = ebx;
  
    // Check that both operands are heap objects.
    Label miss;
    __ mov(tmp1, left);
    STATIC_ASSERT(kSmiTag == 0);
    __ and_(tmp1, right);
    __ JumpIfSmi(tmp1, &miss, Label::kNear);
  
    // Check that both operands are unique names. This leaves the instance
    // types loaded in tmp1 and tmp2.
    __ mov(tmp1, FieldOperand(left, HeapObject::kMapOffset));
    __ mov(tmp2, FieldOperand(right, HeapObject::kMapOffset));
    __ movzx_b(tmp1, FieldOperand(tmp1, Map::kInstanceTypeOffset));
    __ movzx_b(tmp2, FieldOperand(tmp2, Map::kInstanceTypeOffset));
  
    __ JumpIfNotUniqueNameInstanceType(tmp1, &miss, Label::kNear);
    __ JumpIfNotUniqueNameInstanceType(tmp2, &miss, Label::kNear);
  
    // Unique names are compared by identity.
    Label done;
    __ cmp(left, right);
    // Make sure eax is non-zero. At this point input operands are
    // guaranteed to be non-zero.
    DCHECK(right.is(eax));
    __ j(not_equal, &done, Label::kNear);
    STATIC_ASSERT(EQUAL == 0);
    STATIC_ASSERT(kSmiTag == 0);
    __ Move(eax, Immediate(Smi::FromInt(EQUAL)));
    __ bind(&done);
    __ ret(0);
  
    __ bind(&miss);
    GenerateMiss(masm);
  }
  
  
  void CompareICStub::GenerateStrings(MacroAssembler* masm) {
    DCHECK(state() == CompareICState::STRING);
    Label miss;
  
    bool equality = Token::IsEqualityOp(op());
  
    // Registers containing left and right operands respectively.
    Register left = edx;
    Register right = eax;
    Register tmp1 = ecx;
    Register tmp2 = ebx;
    Register tmp3 = edi;
  
    // Check that both operands are heap objects.
    __ mov(tmp1, left);
    STATIC_ASSERT(kSmiTag == 0);
    __ and_(tmp1, right);
    __ JumpIfSmi(tmp1, &miss);
  
    // Check that both operands are strings. This leaves the instance
    // types loaded in tmp1 and tmp2.
    __ mov(tmp1, FieldOperand(left, HeapObject::kMapOffset));
    __ mov(tmp2, FieldOperand(right, HeapObject::kMapOffset));
    __ movzx_b(tmp1, FieldOperand(tmp1, Map::kInstanceTypeOffset));
    __ movzx_b(tmp2, FieldOperand(tmp2, Map::kInstanceTypeOffset));
    __ mov(tmp3, tmp1);
    STATIC_ASSERT(kNotStringTag != 0);
    __ or_(tmp3, tmp2);
    __ test(tmp3, Immediate(kIsNotStringMask));
    __ j(not_zero, &miss);
  
    // Fast check for identical strings.
    Label not_same;
    __ cmp(left, right);
    __ j(not_equal, &not_same, Label::kNear);
    STATIC_ASSERT(EQUAL == 0);
    STATIC_ASSERT(kSmiTag == 0);
    __ Move(eax, Immediate(Smi::FromInt(EQUAL)));
    __ ret(0);
  
    // Handle not identical strings.
    __ bind(&not_same);
  
    // Check that both strings are internalized. If they are, we're done
    // because we already know they are not identical.  But in the case of
    // non-equality compare, we still need to determine the order. We
    // also know they are both strings.
    if (equality) {
      Label do_compare;
      STATIC_ASSERT(kInternalizedTag == 0);
      __ or_(tmp1, tmp2);
      __ test(tmp1, Immediate(kIsNotInternalizedMask));
      __ j(not_zero, &do_compare, Label::kNear);
      // Make sure eax is non-zero. At this point input operands are
      // guaranteed to be non-zero.
      DCHECK(right.is(eax));
      __ ret(0);
      __ bind(&do_compare);
    }
  
    // Check that both strings are sequential one-byte.
    Label runtime;
    __ JumpIfNotBothSequentialOneByteStrings(left, right, tmp1, tmp2, &runtime);
  
    // Compare flat one byte strings. Returns when done.
    if (equality) {
      StringHelper::GenerateFlatOneByteStringEquals(masm, left, right, tmp1,
                                                    tmp2);
    } else {
      StringHelper::GenerateCompareFlatOneByteStrings(masm, left, right, tmp1,
                                                      tmp2, tmp3);
    }
  
    // Handle more complex cases in runtime.
    __ bind(&runtime);
    __ pop(tmp1);  // Return address.
    __ push(left);
    __ push(right);
    __ push(tmp1);
    if (equality) {
      __ TailCallRuntime(Runtime::kStringEquals, 2, 1);
    } else {
      __ TailCallRuntime(Runtime::kStringCompare, 2, 1);
    }
  
    __ bind(&miss);
    GenerateMiss(masm);
  }
  
  
  void CompareICStub::GenerateObjects(MacroAssembler* masm) {
    DCHECK(state() == CompareICState::OBJECT);
    Label miss;
    __ mov(ecx, edx);
    __ and_(ecx, eax);
    __ JumpIfSmi(ecx, &miss, Label::kNear);
  
    __ CmpObjectType(eax, JS_OBJECT_TYPE, ecx);
    __ j(not_equal, &miss, Label::kNear);
    __ CmpObjectType(edx, JS_OBJECT_TYPE, ecx);
    __ j(not_equal, &miss, Label::kNear);
  
    DCHECK(GetCondition() == equal);
    __ sub(eax, edx);
    __ ret(0);
  
    __ bind(&miss);
    GenerateMiss(masm);
  }
  
  
  void CompareICStub::GenerateKnownObjects(MacroAssembler* masm) {
    Label miss;
    __ mov(ecx, edx);
    __ and_(ecx, eax);
    __ JumpIfSmi(ecx, &miss, Label::kNear);
  
    __ mov(ecx, FieldOperand(eax, HeapObject::kMapOffset));
    __ mov(ebx, FieldOperand(edx, HeapObject::kMapOffset));
    __ cmp(ecx, known_map_);
    __ j(not_equal, &miss, Label::kNear);
    __ cmp(ebx, known_map_);
    __ j(not_equal, &miss, Label::kNear);
  
    __ sub(eax, edx);
    __ ret(0);
  
    __ bind(&miss);
    GenerateMiss(masm);
  }
  
  
  void CompareICStub::GenerateMiss(MacroAssembler* masm) {
    {
      // Call the runtime system in a fresh internal frame.
      ExternalReference miss = ExternalReference(IC_Utility(IC::kCompareIC_Miss),
                                                 isolate());
      FrameScope scope(masm, StackFrame::INTERNAL);
      __ push(edx);  // Preserve edx and eax.
      __ push(eax);
      __ push(edx);  // And also use them as the arguments.
      __ push(eax);
      __ push(Immediate(Smi::FromInt(op())));
      __ CallExternalReference(miss, 3);
      // Compute the entry point of the rewritten stub.
      __ lea(edi, FieldOperand(eax, Code::kHeaderSize));
      __ pop(eax);
      __ pop(edx);
    }
  
    // Do a tail call to the rewritten stub.
    __ jmp(edi);
  }
  
  
  // Helper function used to check that the dictionary doesn't contain
  // the property. This function may return false negatives, so miss_label
  // must always call a backup property check that is complete.
  // This function is safe to call if the receiver has fast properties.
  // Name must be a unique name and receiver must be a heap object.
  void NameDictionaryLookupStub::GenerateNegativeLookup(MacroAssembler* masm,
                                                        Label* miss,
                                                        Label* done,
                                                        Register properties,
                                                        Handle<Name> name,
                                                        Register r0) {
    DCHECK(name->IsUniqueName());
  
    // If names of slots in range from 1 to kProbes - 1 for the hash value are
    // not equal to the name and kProbes-th slot is not used (its name is the
    // undefined value), it guarantees the hash table doesn't contain the
    // property. It's true even if some slots represent deleted properties
    // (their names are the hole value).
    for (int i = 0; i < kInlinedProbes; i++) {
      // Compute the masked index: (hash + i + i * i) & mask.
      Register index = r0;
      // Capacity is smi 2^n.
      __ mov(index, FieldOperand(properties, kCapacityOffset));
      __ dec(index);
      __ and_(index,
              Immediate(Smi::FromInt(name->Hash() +
                                     NameDictionary::GetProbeOffset(i))));
  
      // Scale the index by multiplying by the entry size.
      DCHECK(NameDictionary::kEntrySize == 3);
      __ lea(index, Operand(index, index, times_2, 0));  // index *= 3.
      Register entity_name = r0;
      // Having undefined at this place means the name is not contained.
      DCHECK_EQ(kSmiTagSize, 1);
      __ mov(entity_name, Operand(properties, index, times_half_pointer_size,
                                  kElementsStartOffset - kHeapObjectTag));
      __ cmp(entity_name, masm->isolate()->factory()->undefined_value());
      __ j(equal, done);
  
      // Stop if found the property.
      __ cmp(entity_name, Handle<Name>(name));
      __ j(equal, miss);
  
      Label good;
      // Check for the hole and skip.
      __ cmp(entity_name, masm->isolate()->factory()->the_hole_value());
      __ j(equal, &good, Label::kNear);
  
      // Check if the entry name is not a unique name.
      __ mov(entity_name, FieldOperand(entity_name, HeapObject::kMapOffset));
      __ JumpIfNotUniqueNameInstanceType(
          FieldOperand(entity_name, Map::kInstanceTypeOffset), miss);
      __ bind(&good);
    }
  
    NameDictionaryLookupStub stub(masm->isolate(), properties, r0, r0,
                                  NEGATIVE_LOOKUP);
    __ push(Immediate(Handle<Object>(name)));
    __ push(Immediate(name->Hash()));
    __ CallStub(&stub);
    __ test(r0, r0);
    __ j(not_zero, miss);
    __ jmp(done);
  }
  
  
  // Probe the name dictionary in the |elements| register. Jump to the
  // |done| label if a property with the given name is found leaving the
  // index into the dictionary in |r0|. Jump to the |miss| label
  // otherwise.
  void NameDictionaryLookupStub::GeneratePositiveLookup(MacroAssembler* masm,
                                                        Label* miss,
                                                        Label* done,
                                                        Register elements,
                                                        Register name,
                                                        Register r0,
                                                        Register r1) {
    DCHECK(!elements.is(r0));
    DCHECK(!elements.is(r1));
    DCHECK(!name.is(r0));
    DCHECK(!name.is(r1));
  
    __ AssertName(name);
  
    __ mov(r1, FieldOperand(elements, kCapacityOffset));
    __ shr(r1, kSmiTagSize);  // convert smi to int
    __ dec(r1);
  
    // Generate an unrolled loop that performs a few probes before
    // giving up. Measurements done on Gmail indicate that 2 probes
    // cover ~93% of loads from dictionaries.
    for (int i = 0; i < kInlinedProbes; i++) {
      // Compute the masked index: (hash + i + i * i) & mask.
      __ mov(r0, FieldOperand(name, Name::kHashFieldOffset));
      __ shr(r0, Name::kHashShift);
      if (i > 0) {
        __ add(r0, Immediate(NameDictionary::GetProbeOffset(i)));
      }
      __ and_(r0, r1);
  
      // Scale the index by multiplying by the entry size.
      DCHECK(NameDictionary::kEntrySize == 3);
      __ lea(r0, Operand(r0, r0, times_2, 0));  // r0 = r0 * 3
  
      // Check if the key is identical to the name.
      __ cmp(name, Operand(elements,
                           r0,
                           times_4,
                           kElementsStartOffset - kHeapObjectTag));
      __ j(equal, done);
    }
  
    NameDictionaryLookupStub stub(masm->isolate(), elements, r1, r0,
                                  POSITIVE_LOOKUP);
    __ push(name);
    __ mov(r0, FieldOperand(name, Name::kHashFieldOffset));
    __ shr(r0, Name::kHashShift);
    __ push(r0);
    __ CallStub(&stub);
  
    __ test(r1, r1);
    __ j(zero, miss);
    __ jmp(done);
  }
  
  
  void NameDictionaryLookupStub::Generate(MacroAssembler* masm) {
    // This stub overrides SometimesSetsUpAFrame() to return false.  That means
    // we cannot call anything that could cause a GC from this stub.
    // Stack frame on entry:
    //  esp[0 * kPointerSize]: return address.
    //  esp[1 * kPointerSize]: key's hash.
    //  esp[2 * kPointerSize]: key.
    // Registers:
    //  dictionary_: NameDictionary to probe.
    //  result_: used as scratch.
    //  index_: will hold an index of entry if lookup is successful.
    //          might alias with result_.
    // Returns:
    //  result_ is zero if lookup failed, non zero otherwise.
  
    Label in_dictionary, maybe_in_dictionary, not_in_dictionary;
  
    Register scratch = result();
  
    __ mov(scratch, FieldOperand(dictionary(), kCapacityOffset));
    __ dec(scratch);
    __ SmiUntag(scratch);
    __ push(scratch);
  
    // If names of slots in range from 1 to kProbes - 1 for the hash value are
    // not equal to the name and kProbes-th slot is not used (its name is the
    // undefined value), it guarantees the hash table doesn't contain the
    // property. It's true even if some slots represent deleted properties
    // (their names are the null value).
    for (int i = kInlinedProbes; i < kTotalProbes; i++) {
      // Compute the masked index: (hash + i + i * i) & mask.
      __ mov(scratch, Operand(esp, 2 * kPointerSize));
      if (i > 0) {
        __ add(scratch, Immediate(NameDictionary::GetProbeOffset(i)));
      }
      __ and_(scratch, Operand(esp, 0));
  
      // Scale the index by multiplying by the entry size.
      DCHECK(NameDictionary::kEntrySize == 3);
      __ lea(index(), Operand(scratch, scratch, times_2, 0));  // index *= 3.
  
      // Having undefined at this place means the name is not contained.
      DCHECK_EQ(kSmiTagSize, 1);
      __ mov(scratch, Operand(dictionary(), index(), times_pointer_size,
                              kElementsStartOffset - kHeapObjectTag));
      __ cmp(scratch, isolate()->factory()->undefined_value());
      __ j(equal, &not_in_dictionary);
  
      // Stop if found the property.
      __ cmp(scratch, Operand(esp, 3 * kPointerSize));
      __ j(equal, &in_dictionary);
  
      if (i != kTotalProbes - 1 && mode() == NEGATIVE_LOOKUP) {
        // If we hit a key that is not a unique name during negative
        // lookup we have to bailout as this key might be equal to the
        // key we are looking for.
  
        // Check if the entry name is not a unique name.
        __ mov(scratch, FieldOperand(scratch, HeapObject::kMapOffset));
        __ JumpIfNotUniqueNameInstanceType(
            FieldOperand(scratch, Map::kInstanceTypeOffset),
            &maybe_in_dictionary);
      }
    }
  
    __ bind(&maybe_in_dictionary);
    // If we are doing negative lookup then probing failure should be
    // treated as a lookup success. For positive lookup probing failure
    // should be treated as lookup failure.
    if (mode() == POSITIVE_LOOKUP) {
      __ mov(result(), Immediate(0));
      __ Drop(1);
      __ ret(2 * kPointerSize);
    }
  
    __ bind(&in_dictionary);
    __ mov(result(), Immediate(1));
    __ Drop(1);
    __ ret(2 * kPointerSize);
  
    __ bind(&not_in_dictionary);
    __ mov(result(), Immediate(0));
    __ Drop(1);
    __ ret(2 * kPointerSize);
  }
  
  
  void StoreBufferOverflowStub::GenerateFixedRegStubsAheadOfTime(
      Isolate* isolate) {
    StoreBufferOverflowStub stub(isolate, kDontSaveFPRegs);
    stub.GetCode();
    StoreBufferOverflowStub stub2(isolate, kSaveFPRegs);
    stub2.GetCode();
  }
  
  
  // Takes the input in 3 registers: address_ value_ and object_.  A pointer to
  // the value has just been written into the object, now this stub makes sure
  // we keep the GC informed.  The word in the object where the value has been
  // written is in the address register.
  void RecordWriteStub::Generate(MacroAssembler* masm) {
    Label skip_to_incremental_noncompacting;
    Label skip_to_incremental_compacting;
  
    // The first two instructions are generated with labels so as to get the
    // offset fixed up correctly by the bind(Label*) call.  We patch it back and
    // forth between a compare instructions (a nop in this position) and the
    // real branch when we start and stop incremental heap marking.
    __ jmp(&skip_to_incremental_noncompacting, Label::kNear);
    __ jmp(&skip_to_incremental_compacting, Label::kFar);
  
    if (remembered_set_action() == EMIT_REMEMBERED_SET) {
      __ RememberedSetHelper(object(), address(), value(), save_fp_regs_mode(),
                             MacroAssembler::kReturnAtEnd);
    } else {
      __ ret(0);
    }
  
    __ bind(&skip_to_incremental_noncompacting);
    GenerateIncremental(masm, INCREMENTAL);
  
    __ bind(&skip_to_incremental_compacting);
    GenerateIncremental(masm, INCREMENTAL_COMPACTION);
  
    // Initial mode of the stub is expected to be STORE_BUFFER_ONLY.
    // Will be checked in IncrementalMarking::ActivateGeneratedStub.
    masm->set_byte_at(0, kTwoByteNopInstruction);
    masm->set_byte_at(2, kFiveByteNopInstruction);
  }
  
  
  void RecordWriteStub::GenerateIncremental(MacroAssembler* masm, Mode mode) {
    regs_.Save(masm);
  
    if (remembered_set_action() == EMIT_REMEMBERED_SET) {
      Label dont_need_remembered_set;
  
      __ mov(regs_.scratch0(), Operand(regs_.address(), 0));
      __ JumpIfNotInNewSpace(regs_.scratch0(),  // Value.
                             regs_.scratch0(),
                             &dont_need_remembered_set);
  
      __ CheckPageFlag(regs_.object(),
                       regs_.scratch0(),
                       1 << MemoryChunk::SCAN_ON_SCAVENGE,
                       not_zero,
                       &dont_need_remembered_set);
  
      // First notify the incremental marker if necessary, then update the
      // remembered set.
      CheckNeedsToInformIncrementalMarker(
          masm,
          kUpdateRememberedSetOnNoNeedToInformIncrementalMarker,
          mode);
      InformIncrementalMarker(masm);
      regs_.Restore(masm);
      __ RememberedSetHelper(object(), address(), value(), save_fp_regs_mode(),
                             MacroAssembler::kReturnAtEnd);
  
      __ bind(&dont_need_remembered_set);
    }
  
    CheckNeedsToInformIncrementalMarker(
        masm,
        kReturnOnNoNeedToInformIncrementalMarker,
        mode);
    InformIncrementalMarker(masm);
    regs_.Restore(masm);
    __ ret(0);
  }
  
  
  void RecordWriteStub::InformIncrementalMarker(MacroAssembler* masm) {
    regs_.SaveCallerSaveRegisters(masm, save_fp_regs_mode());
    int argument_count = 3;
    __ PrepareCallCFunction(argument_count, regs_.scratch0());
    __ mov(Operand(esp, 0 * kPointerSize), regs_.object());
    __ mov(Operand(esp, 1 * kPointerSize), regs_.address());  // Slot.
    __ mov(Operand(esp, 2 * kPointerSize),
           Immediate(ExternalReference::isolate_address(isolate())));
  
    AllowExternalCallThatCantCauseGC scope(masm);
    __ CallCFunction(
        ExternalReference::incremental_marking_record_write_function(isolate()),
        argument_count);
  
    regs_.RestoreCallerSaveRegisters(masm, save_fp_regs_mode());
  }
  
  
  void RecordWriteStub::CheckNeedsToInformIncrementalMarker(
      MacroAssembler* masm,
      OnNoNeedToInformIncrementalMarker on_no_need,
      Mode mode) {
    Label object_is_black, need_incremental, need_incremental_pop_object;
  
    __ mov(regs_.scratch0(), Immediate(~Page::kPageAlignmentMask));
    __ and_(regs_.scratch0(), regs_.object());
    __ mov(regs_.scratch1(),
           Operand(regs_.scratch0(),
                   MemoryChunk::kWriteBarrierCounterOffset));
    __ sub(regs_.scratch1(), Immediate(1));
    __ mov(Operand(regs_.scratch0(),
                   MemoryChunk::kWriteBarrierCounterOffset),
           regs_.scratch1());
    __ j(negative, &need_incremental);
  
    // Let's look at the color of the object:  If it is not black we don't have
    // to inform the incremental marker.
    __ JumpIfBlack(regs_.object(),
                   regs_.scratch0(),
                   regs_.scratch1(),
                   &object_is_black,
                   Label::kNear);
  
    regs_.Restore(masm);
    if (on_no_need == kUpdateRememberedSetOnNoNeedToInformIncrementalMarker) {
      __ RememberedSetHelper(object(), address(), value(), save_fp_regs_mode(),
                             MacroAssembler::kReturnAtEnd);
    } else {
      __ ret(0);
    }
  
    __ bind(&object_is_black);
  
    // Get the value from the slot.
    __ mov(regs_.scratch0(), Operand(regs_.address(), 0));
  
    if (mode == INCREMENTAL_COMPACTION) {
      Label ensure_not_white;
  
      __ CheckPageFlag(regs_.scratch0(),  // Contains value.
                       regs_.scratch1(),  // Scratch.
                       MemoryChunk::kEvacuationCandidateMask,
                       zero,
                       &ensure_not_white,
                       Label::kNear);
  
      __ CheckPageFlag(regs_.object(),
                       regs_.scratch1(),  // Scratch.
                       MemoryChunk::kSkipEvacuationSlotsRecordingMask,
                       not_zero,
                       &ensure_not_white,
                       Label::kNear);
  
      __ jmp(&need_incremental);
  
      __ bind(&ensure_not_white);
    }
  
    // We need an extra register for this, so we push the object register
    // temporarily.
    __ push(regs_.object());
    __ EnsureNotWhite(regs_.scratch0(),  // The value.
                      regs_.scratch1(),  // Scratch.
                      regs_.object(),  // Scratch.
                      &need_incremental_pop_object,
                      Label::kNear);
    __ pop(regs_.object());
  
    regs_.Restore(masm);
    if (on_no_need == kUpdateRememberedSetOnNoNeedToInformIncrementalMarker) {
      __ RememberedSetHelper(object(), address(), value(), save_fp_regs_mode(),
                             MacroAssembler::kReturnAtEnd);
    } else {
      __ ret(0);
    }
  
    __ bind(&need_incremental_pop_object);
    __ pop(regs_.object());
  
    __ bind(&need_incremental);
  
    // Fall through when we need to inform the incremental marker.
  }
  
  
  void StoreArrayLiteralElementStub::Generate(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- eax    : element value to store
    //  -- ecx    : element index as smi
    //  -- esp[0] : return address
    //  -- esp[4] : array literal index in function
    //  -- esp[8] : array literal
    // clobbers ebx, edx, edi
    // -----------------------------------
  
    Label element_done;
    Label double_elements;
    Label smi_element;
    Label slow_elements;
    Label slow_elements_from_double;
    Label fast_elements;
  
    // Get array literal index, array literal and its map.
    __ mov(edx, Operand(esp, 1 * kPointerSize));
    __ mov(ebx, Operand(esp, 2 * kPointerSize));
    __ mov(edi, FieldOperand(ebx, JSObject::kMapOffset));
  
    __ CheckFastElements(edi, &double_elements);
  
    // Check for FAST_*_SMI_ELEMENTS or FAST_*_ELEMENTS elements
    __ JumpIfSmi(eax, &smi_element);
    __ CheckFastSmiElements(edi, &fast_elements, Label::kNear);
  
    // Store into the array literal requires a elements transition. Call into
    // the runtime.
  
    __ bind(&slow_elements);
    __ pop(edi);  // Pop return address and remember to put back later for tail
                  // call.
    __ push(ebx);
    __ push(ecx);
    __ push(eax);
    __ mov(ebx, Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
    __ push(FieldOperand(ebx, JSFunction::kLiteralsOffset));
    __ push(edx);
    __ push(edi);  // Return return address so that tail call returns to right
                   // place.
    __ TailCallRuntime(Runtime::kStoreArrayLiteralElement, 5, 1);
  
    __ bind(&slow_elements_from_double);
    __ pop(edx);
    __ jmp(&slow_elements);
  
    // Array literal has ElementsKind of FAST_*_ELEMENTS and value is an object.
    __ bind(&fast_elements);
    __ mov(ebx, FieldOperand(ebx, JSObject::kElementsOffset));
    __ lea(ecx, FieldOperand(ebx, ecx, times_half_pointer_size,
                             FixedArrayBase::kHeaderSize));
    __ mov(Operand(ecx, 0), eax);
    // Update the write barrier for the array store.
    __ RecordWrite(ebx, ecx, eax, kDontSaveFPRegs, EMIT_REMEMBERED_SET,
                   OMIT_SMI_CHECK);
    __ ret(0);
  
    // Array literal has ElementsKind of FAST_*_SMI_ELEMENTS or FAST_*_ELEMENTS,
    // and value is Smi.
    __ bind(&smi_element);
    __ mov(ebx, FieldOperand(ebx, JSObject::kElementsOffset));
    __ mov(FieldOperand(ebx, ecx, times_half_pointer_size,
                        FixedArrayBase::kHeaderSize), eax);
    __ ret(0);
  
    // Array literal has ElementsKind of FAST_*_DOUBLE_ELEMENTS.
    __ bind(&double_elements);
  
    __ push(edx);
    __ mov(edx, FieldOperand(ebx, JSObject::kElementsOffset));
    __ StoreNumberToDoubleElements(eax,
                                   edx,
                                   ecx,
                                   edi,
                                   &slow_elements_from_double,
                                   false);
    __ pop(edx);
    __ ret(0);
  }
  
  
  void StubFailureTrampolineStub::Generate(MacroAssembler* masm) {
    CEntryStub ces(isolate(), 1, kSaveFPRegs);
    __ call(ces.GetCode(), RelocInfo::CODE_TARGET);
    int parameter_count_offset =
        StubFailureTrampolineFrame::kCallerStackParameterCountFrameOffset;
    __ mov(ebx, MemOperand(ebp, parameter_count_offset));
    masm->LeaveFrame(StackFrame::STUB_FAILURE_TRAMPOLINE);
    __ pop(ecx);
    int additional_offset =
        function_mode() == JS_FUNCTION_STUB_MODE ? kPointerSize : 0;
    __ lea(esp, MemOperand(esp, ebx, times_pointer_size, additional_offset));
    __ jmp(ecx);  // Return to IC Miss stub, continuation still on stack.
  }
  
  
  void LoadICTrampolineStub::Generate(MacroAssembler* masm) {
    EmitLoadTypeFeedbackVector(masm, VectorLoadICDescriptor::VectorRegister());
    VectorLoadStub stub(isolate(), state());
    __ jmp(stub.GetCode(), RelocInfo::CODE_TARGET);
  }
  
  
  void KeyedLoadICTrampolineStub::Generate(MacroAssembler* masm) {
    EmitLoadTypeFeedbackVector(masm, VectorLoadICDescriptor::VectorRegister());
    VectorKeyedLoadStub stub(isolate());
    __ jmp(stub.GetCode(), RelocInfo::CODE_TARGET);
  }
  
  
  void ProfileEntryHookStub::MaybeCallEntryHook(MacroAssembler* masm) {
    if (masm->isolate()->function_entry_hook() != NULL) {
      ProfileEntryHookStub stub(masm->isolate());
      masm->CallStub(&stub);
    }
  }
  
  
  void ProfileEntryHookStub::Generate(MacroAssembler* masm) {
    // Save volatile registers.
    const int kNumSavedRegisters = 3;
    __ push(eax);
    __ push(ecx);
    __ push(edx);
  
    // Calculate and push the original stack pointer.
    __ lea(eax, Operand(esp, (kNumSavedRegisters + 1) * kPointerSize));
    __ push(eax);
  
    // Retrieve our return address and use it to calculate the calling
    // function's address.
    __ mov(eax, Operand(esp, (kNumSavedRegisters + 1) * kPointerSize));
    __ sub(eax, Immediate(Assembler::kCallInstructionLength));
    __ push(eax);
  
    // Call the entry hook.
    DCHECK(isolate()->function_entry_hook() != NULL);
    __ call(FUNCTION_ADDR(isolate()->function_entry_hook()),
            RelocInfo::RUNTIME_ENTRY);
    __ add(esp, Immediate(2 * kPointerSize));
  
    // Restore ecx.
    __ pop(edx);
    __ pop(ecx);
    __ pop(eax);
  
    __ ret(0);
  }
  
  
  template<class T>
  static void CreateArrayDispatch(MacroAssembler* masm,
                                  AllocationSiteOverrideMode mode) {
    if (mode == DISABLE_ALLOCATION_SITES) {
      T stub(masm->isolate(),
             GetInitialFastElementsKind(),
             mode);
      __ TailCallStub(&stub);
    } else if (mode == DONT_OVERRIDE) {
      int last_index = GetSequenceIndexFromFastElementsKind(
          TERMINAL_FAST_ELEMENTS_KIND);
      for (int i = 0; i <= last_index; ++i) {
        Label next;
        ElementsKind kind = GetFastElementsKindFromSequenceIndex(i);
        __ cmp(edx, kind);
        __ j(not_equal, &next);
        T stub(masm->isolate(), kind);
        __ TailCallStub(&stub);
        __ bind(&next);
      }
  
      // If we reached this point there is a problem.
      __ Abort(kUnexpectedElementsKindInArrayConstructor);
    } else {
      UNREACHABLE();
    }
  }
  
  
  static void CreateArrayDispatchOneArgument(MacroAssembler* masm,
                                             AllocationSiteOverrideMode mode) {
    // ebx - allocation site (if mode != DISABLE_ALLOCATION_SITES)
    // edx - kind (if mode != DISABLE_ALLOCATION_SITES)
    // eax - number of arguments
    // edi - constructor?
    // esp[0] - return address
    // esp[4] - last argument
    Label normal_sequence;
    if (mode == DONT_OVERRIDE) {
      DCHECK(FAST_SMI_ELEMENTS == 0);
      DCHECK(FAST_HOLEY_SMI_ELEMENTS == 1);
      DCHECK(FAST_ELEMENTS == 2);
      DCHECK(FAST_HOLEY_ELEMENTS == 3);
      DCHECK(FAST_DOUBLE_ELEMENTS == 4);
      DCHECK(FAST_HOLEY_DOUBLE_ELEMENTS == 5);
  
      // is the low bit set? If so, we are holey and that is good.
      __ test_b(edx, 1);
      __ j(not_zero, &normal_sequence);
    }
  
    // look at the first argument
    __ mov(ecx, Operand(esp, kPointerSize));
    __ test(ecx, ecx);
    __ j(zero, &normal_sequence);
  
    if (mode == DISABLE_ALLOCATION_SITES) {
      ElementsKind initial = GetInitialFastElementsKind();
      ElementsKind holey_initial = GetHoleyElementsKind(initial);
  
      ArraySingleArgumentConstructorStub stub_holey(masm->isolate(),
                                                    holey_initial,
                                                    DISABLE_ALLOCATION_SITES);
      __ TailCallStub(&stub_holey);
  
      __ bind(&normal_sequence);
      ArraySingleArgumentConstructorStub stub(masm->isolate(),
                                              initial,
                                              DISABLE_ALLOCATION_SITES);
      __ TailCallStub(&stub);
    } else if (mode == DONT_OVERRIDE) {
      // We are going to create a holey array, but our kind is non-holey.
      // Fix kind and retry.
      __ inc(edx);
  
      if (FLAG_debug_code) {
        Handle<Map> allocation_site_map =
            masm->isolate()->factory()->allocation_site_map();
        __ cmp(FieldOperand(ebx, 0), Immediate(allocation_site_map));
        __ Assert(equal, kExpectedAllocationSite);
      }
  
      // Save the resulting elements kind in type info. We can't just store r3
      // in the AllocationSite::transition_info field because elements kind is
      // restricted to a portion of the field...upper bits need to be left alone.
      STATIC_ASSERT(AllocationSite::ElementsKindBits::kShift == 0);
      __ add(FieldOperand(ebx, AllocationSite::kTransitionInfoOffset),
             Immediate(Smi::FromInt(kFastElementsKindPackedToHoley)));
  
      __ bind(&normal_sequence);
      int last_index = GetSequenceIndexFromFastElementsKind(
          TERMINAL_FAST_ELEMENTS_KIND);
      for (int i = 0; i <= last_index; ++i) {
        Label next;
        ElementsKind kind = GetFastElementsKindFromSequenceIndex(i);
        __ cmp(edx, kind);
        __ j(not_equal, &next);
        ArraySingleArgumentConstructorStub stub(masm->isolate(), kind);
        __ TailCallStub(&stub);
        __ bind(&next);
      }
  
      // If we reached this point there is a problem.
      __ Abort(kUnexpectedElementsKindInArrayConstructor);
    } else {
      UNREACHABLE();
    }
  }
  
  
  template<class T>
  static void ArrayConstructorStubAheadOfTimeHelper(Isolate* isolate) {
    int to_index = GetSequenceIndexFromFastElementsKind(
        TERMINAL_FAST_ELEMENTS_KIND);
    for (int i = 0; i <= to_index; ++i) {
      ElementsKind kind = GetFastElementsKindFromSequenceIndex(i);
      T stub(isolate, kind);
      stub.GetCode();
      if (AllocationSite::GetMode(kind) != DONT_TRACK_ALLOCATION_SITE) {
        T stub1(isolate, kind, DISABLE_ALLOCATION_SITES);
        stub1.GetCode();
      }
    }
  }
  
  
  void ArrayConstructorStubBase::GenerateStubsAheadOfTime(Isolate* isolate) {
    ArrayConstructorStubAheadOfTimeHelper<ArrayNoArgumentConstructorStub>(
        isolate);
    ArrayConstructorStubAheadOfTimeHelper<ArraySingleArgumentConstructorStub>(
        isolate);
    ArrayConstructorStubAheadOfTimeHelper<ArrayNArgumentsConstructorStub>(
        isolate);
  }
  
  
  void InternalArrayConstructorStubBase::GenerateStubsAheadOfTime(
      Isolate* isolate) {
    ElementsKind kinds[2] = { FAST_ELEMENTS, FAST_HOLEY_ELEMENTS };
    for (int i = 0; i < 2; i++) {
      // For internal arrays we only need a few things
      InternalArrayNoArgumentConstructorStub stubh1(isolate, kinds[i]);
      stubh1.GetCode();
      InternalArraySingleArgumentConstructorStub stubh2(isolate, kinds[i]);
      stubh2.GetCode();
      InternalArrayNArgumentsConstructorStub stubh3(isolate, kinds[i]);
      stubh3.GetCode();
    }
  }
  
  
  void ArrayConstructorStub::GenerateDispatchToArrayStub(
      MacroAssembler* masm,
      AllocationSiteOverrideMode mode) {
    if (argument_count() == ANY) {
      Label not_zero_case, not_one_case;
      __ test(eax, eax);
      __ j(not_zero, &not_zero_case);
      CreateArrayDispatch<ArrayNoArgumentConstructorStub>(masm, mode);
  
      __ bind(&not_zero_case);
      __ cmp(eax, 1);
      __ j(greater, &not_one_case);
      CreateArrayDispatchOneArgument(masm, mode);
  
      __ bind(&not_one_case);
      CreateArrayDispatch<ArrayNArgumentsConstructorStub>(masm, mode);
    } else if (argument_count() == NONE) {
      CreateArrayDispatch<ArrayNoArgumentConstructorStub>(masm, mode);
    } else if (argument_count() == ONE) {
      CreateArrayDispatchOneArgument(masm, mode);
    } else if (argument_count() == MORE_THAN_ONE) {
      CreateArrayDispatch<ArrayNArgumentsConstructorStub>(masm, mode);
    } else {
      UNREACHABLE();
    }
  }
  
  
  void ArrayConstructorStub::Generate(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- eax : argc (only if argument_count() == ANY)
    //  -- ebx : AllocationSite or undefined
    //  -- edi : constructor
    //  -- esp[0] : return address
    //  -- esp[4] : last argument
    // -----------------------------------
    if (FLAG_debug_code) {
      // The array construct code is only set for the global and natives
      // builtin Array functions which always have maps.
  
      // Initial map for the builtin Array function should be a map.
      __ mov(ecx, FieldOperand(edi, JSFunction::kPrototypeOrInitialMapOffset));
      // Will both indicate a NULL and a Smi.
      __ test(ecx, Immediate(kSmiTagMask));
      __ Assert(not_zero, kUnexpectedInitialMapForArrayFunction);
      __ CmpObjectType(ecx, MAP_TYPE, ecx);
      __ Assert(equal, kUnexpectedInitialMapForArrayFunction);
  
      // We should either have undefined in ebx or a valid AllocationSite
      __ AssertUndefinedOrAllocationSite(ebx);
    }
  
    Label no_info;
    // If the feedback vector is the undefined value call an array constructor
    // that doesn't use AllocationSites.
    __ cmp(ebx, isolate()->factory()->undefined_value());
    __ j(equal, &no_info);
  
    // Only look at the lower 16 bits of the transition info.
    __ mov(edx, FieldOperand(ebx, AllocationSite::kTransitionInfoOffset));
    __ SmiUntag(edx);
    STATIC_ASSERT(AllocationSite::ElementsKindBits::kShift == 0);
    __ and_(edx, Immediate(AllocationSite::ElementsKindBits::kMask));
    GenerateDispatchToArrayStub(masm, DONT_OVERRIDE);
  
    __ bind(&no_info);
    GenerateDispatchToArrayStub(masm, DISABLE_ALLOCATION_SITES);
  }
  
  
  void InternalArrayConstructorStub::GenerateCase(
      MacroAssembler* masm, ElementsKind kind) {
    Label not_zero_case, not_one_case;
    Label normal_sequence;
  
    __ test(eax, eax);
    __ j(not_zero, &not_zero_case);
    InternalArrayNoArgumentConstructorStub stub0(isolate(), kind);
    __ TailCallStub(&stub0);
  
    __ bind(&not_zero_case);
    __ cmp(eax, 1);
    __ j(greater, &not_one_case);
  
    if (IsFastPackedElementsKind(kind)) {
      // We might need to create a holey array
      // look at the first argument
      __ mov(ecx, Operand(esp, kPointerSize));
      __ test(ecx, ecx);
      __ j(zero, &normal_sequence);
  
      InternalArraySingleArgumentConstructorStub
          stub1_holey(isolate(), GetHoleyElementsKind(kind));
      __ TailCallStub(&stub1_holey);
    }
  
    __ bind(&normal_sequence);
    InternalArraySingleArgumentConstructorStub stub1(isolate(), kind);
    __ TailCallStub(&stub1);
  
    __ bind(&not_one_case);
    InternalArrayNArgumentsConstructorStub stubN(isolate(), kind);
    __ TailCallStub(&stubN);
  }
  
  
  void InternalArrayConstructorStub::Generate(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- eax : argc
    //  -- edi : constructor
    //  -- esp[0] : return address
    //  -- esp[4] : last argument
    // -----------------------------------
  
    if (FLAG_debug_code) {
      // The array construct code is only set for the global and natives
      // builtin Array functions which always have maps.
  
      // Initial map for the builtin Array function should be a map.
      __ mov(ecx, FieldOperand(edi, JSFunction::kPrototypeOrInitialMapOffset));
      // Will both indicate a NULL and a Smi.
      __ test(ecx, Immediate(kSmiTagMask));
      __ Assert(not_zero, kUnexpectedInitialMapForArrayFunction);
      __ CmpObjectType(ecx, MAP_TYPE, ecx);
      __ Assert(equal, kUnexpectedInitialMapForArrayFunction);
    }
  
    // Figure out the right elements kind
    __ mov(ecx, FieldOperand(edi, JSFunction::kPrototypeOrInitialMapOffset));
  
    // Load the map's "bit field 2" into |result|. We only need the first byte,
    // but the following masking takes care of that anyway.
    __ mov(ecx, FieldOperand(ecx, Map::kBitField2Offset));
    // Retrieve elements_kind from bit field 2.
    __ DecodeField<Map::ElementsKindBits>(ecx);
  
    if (FLAG_debug_code) {
      Label done;
      __ cmp(ecx, Immediate(FAST_ELEMENTS));
      __ j(equal, &done);
      __ cmp(ecx, Immediate(FAST_HOLEY_ELEMENTS));
      __ Assert(equal,
                kInvalidElementsKindForInternalArrayOrInternalPackedArray);
      __ bind(&done);
    }
  
    Label fast_elements_case;
    __ cmp(ecx, Immediate(FAST_ELEMENTS));
    __ j(equal, &fast_elements_case);
    GenerateCase(masm, FAST_HOLEY_ELEMENTS);
  
    __ bind(&fast_elements_case);
    GenerateCase(masm, FAST_ELEMENTS);
  }
  
  
  void CallApiFunctionStub::Generate(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- eax                 : callee
    //  -- ebx                 : call_data
    //  -- ecx                 : holder
    //  -- edx                 : api_function_address
    //  -- esi                 : context
    //  --
    //  -- esp[0]              : return address
    //  -- esp[4]              : last argument
    //  -- ...
    //  -- esp[argc * 4]       : first argument
    //  -- esp[(argc + 1) * 4] : receiver
    // -----------------------------------
  
    Register callee = eax;
    Register call_data = ebx;
    Register holder = ecx;
    Register api_function_address = edx;
    Register return_address = edi;
    Register context = esi;
  
    int argc = this->argc();
    bool is_store = this->is_store();
    bool call_data_undefined = this->call_data_undefined();
  
    typedef FunctionCallbackArguments FCA;
  
    STATIC_ASSERT(FCA::kContextSaveIndex == 6);
    STATIC_ASSERT(FCA::kCalleeIndex == 5);
    STATIC_ASSERT(FCA::kDataIndex == 4);
    STATIC_ASSERT(FCA::kReturnValueOffset == 3);
    STATIC_ASSERT(FCA::kReturnValueDefaultValueIndex == 2);
    STATIC_ASSERT(FCA::kIsolateIndex == 1);
    STATIC_ASSERT(FCA::kHolderIndex == 0);
    STATIC_ASSERT(FCA::kArgsLength == 7);
  
    __ pop(return_address);
  
    // context save
    __ push(context);
    // load context from callee
    __ mov(context, FieldOperand(callee, JSFunction::kContextOffset));
  
    // callee
    __ push(callee);
  
    // call data
    __ push(call_data);
  
    Register scratch = call_data;
    if (!call_data_undefined) {
      // return value
      __ push(Immediate(isolate()->factory()->undefined_value()));
      // return value default
      __ push(Immediate(isolate()->factory()->undefined_value()));
    } else {
      // return value
      __ push(scratch);
      // return value default
      __ push(scratch);
    }
    // isolate
    __ push(Immediate(reinterpret_cast<int>(isolate())));
    // holder
    __ push(holder);
  
    __ mov(scratch, esp);
  
    // return address
    __ push(return_address);
  
    // API function gets reference to the v8::Arguments. If CPU profiler
    // is enabled wrapper function will be called and we need to pass
    // address of the callback as additional parameter, always allocate
    // space for it.
    const int kApiArgc = 1 + 1;
  
    // Allocate the v8::Arguments structure in the arguments' space since
    // it's not controlled by GC.
    const int kApiStackSpace = 4;
  
    __ PrepareCallApiFunction(kApiArgc + kApiStackSpace);
  
    // FunctionCallbackInfo::implicit_args_.
    __ mov(ApiParameterOperand(2), scratch);
    __ add(scratch, Immediate((argc + FCA::kArgsLength - 1) * kPointerSize));
    // FunctionCallbackInfo::values_.
    __ mov(ApiParameterOperand(3), scratch);
    // FunctionCallbackInfo::length_.
    __ Move(ApiParameterOperand(4), Immediate(argc));
    // FunctionCallbackInfo::is_construct_call_.
    __ Move(ApiParameterOperand(5), Immediate(0));
  
    // v8::InvocationCallback's argument.
    __ lea(scratch, ApiParameterOperand(2));
    __ mov(ApiParameterOperand(0), scratch);
  
    ExternalReference thunk_ref =
        ExternalReference::invoke_function_callback(isolate());
  
    Operand context_restore_operand(ebp,
                                    (2 + FCA::kContextSaveIndex) * kPointerSize);
    // Stores return the first js argument
    int return_value_offset = 0;
    if (is_store) {
      return_value_offset = 2 + FCA::kArgsLength;
    } else {
      return_value_offset = 2 + FCA::kReturnValueOffset;
    }
    Operand return_value_operand(ebp, return_value_offset * kPointerSize);
    __ CallApiFunctionAndReturn(api_function_address,
                                thunk_ref,
                                ApiParameterOperand(1),
                                argc + FCA::kArgsLength + 1,
                                return_value_operand,
                                &context_restore_operand);
  }
  
  
  void CallApiGetterStub::Generate(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- esp[0]                  : return address
    //  -- esp[4]                  : name
    //  -- esp[8 - kArgsLength*4]  : PropertyCallbackArguments object
    //  -- ...
    //  -- edx                    : api_function_address
    // -----------------------------------
    DCHECK(edx.is(ApiGetterDescriptor::function_address()));
  
    // array for v8::Arguments::values_, handler for name and pointer
    // to the values (it considered as smi in GC).
    const int kStackSpace = PropertyCallbackArguments::kArgsLength + 2;
    // Allocate space for opional callback address parameter in case
    // CPU profiler is active.
    const int kApiArgc = 2 + 1;
  
    Register api_function_address = edx;
    Register scratch = ebx;
  
    // load address of name
    __ lea(scratch, Operand(esp, 1 * kPointerSize));
  
    __ PrepareCallApiFunction(kApiArgc);
    __ mov(ApiParameterOperand(0), scratch);  // name.
    __ add(scratch, Immediate(kPointerSize));
    __ mov(ApiParameterOperand(1), scratch);  // arguments pointer.
  
    ExternalReference thunk_ref =
        ExternalReference::invoke_accessor_getter_callback(isolate());
  
    __ CallApiFunctionAndReturn(api_function_address,
                                thunk_ref,
                                ApiParameterOperand(2),
                                kStackSpace,
                                Operand(ebp, 7 * kPointerSize),
                                NULL);
  }
  
  
  #undef __
  
  } }  // namespace v8::internal
  
  #endif  // V8_TARGET_ARCH_X87
  