src/ia32/builtins-ia32.cc

// Copyright 2010 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
//       disclaimer in the documentation and/or other materials provided
//       with the distribution.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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#include "v8.h"

#if defined(V8_TARGET_ARCH_IA32)

#include "codegen-inl.h"
#include "deoptimizer.h"
#include "full-codegen.h"

namespace v8 {
namespace internal {


#define __ ACCESS_MASM(masm)


void Builtins::Generate_Adaptor(MacroAssembler* masm,
                                CFunctionId id,
                                BuiltinExtraArguments extra_args) {
  // ----------- S t a t e -------------
  //  -- eax                : number of arguments excluding receiver
  //  -- edi                : called function (only guaranteed when
  //                          extra_args requires it)
  //  -- esi                : context
  //  -- esp[0]             : return address
  //  -- esp[4]             : last argument
  //  -- ...
  //  -- esp[4 * argc]      : first argument (argc == eax)
  //  -- esp[4 * (argc +1)] : receiver
  // -----------------------------------

  // Insert extra arguments.
  int num_extra_args = 0;
  if (extra_args == NEEDS_CALLED_FUNCTION) {
    num_extra_args = 1;
    Register scratch = ebx;
    __ pop(scratch);  // Save return address.
    __ push(edi);
    __ push(scratch);  // Restore return address.
  } else {
    ASSERT(extra_args == NO_EXTRA_ARGUMENTS);
  }

  // JumpToExternalReference expects eax to contain the number of arguments
  // including the receiver and the extra arguments.
  __ add(Operand(eax), Immediate(num_extra_args + 1));
  __ JumpToExternalReference(ExternalReference(id, masm->isolate()));
}


void Builtins::Generate_JSConstructCall(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- eax: number of arguments
  //  -- edi: constructor function
  // -----------------------------------

  Label non_function_call;
  // Check that function is not a smi.
  __ test(edi, Immediate(kSmiTagMask));
  __ j(zero, &non_function_call);
  // Check that function is a JSFunction.
  __ CmpObjectType(edi, JS_FUNCTION_TYPE, ecx);
  __ j(not_equal, &non_function_call);

  // Jump to the function-specific construct stub.
  __ mov(ebx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
  __ mov(ebx, FieldOperand(ebx, SharedFunctionInfo::kConstructStubOffset));
  __ lea(ebx, FieldOperand(ebx, Code::kHeaderSize));
  __ jmp(Operand(ebx));

  // edi: called object
  // eax: number of arguments
  __ bind(&non_function_call);
  // Set expected number of arguments to zero (not changing eax).
  __ Set(ebx, Immediate(0));
  __ GetBuiltinEntry(edx, Builtins::CALL_NON_FUNCTION_AS_CONSTRUCTOR);
  Handle<Code> arguments_adaptor =
      masm->isolate()->builtins()->ArgumentsAdaptorTrampoline();
  __ jmp(arguments_adaptor, RelocInfo::CODE_TARGET);
}


static void Generate_JSConstructStubHelper(MacroAssembler* masm,
                                           bool is_api_function,
                                           bool count_constructions) {
  // Should never count constructions for api objects.
  ASSERT(!is_api_function || !count_constructions);

  // Enter a construct frame.
  __ EnterConstructFrame();

  // Store a smi-tagged arguments count on the stack.
  __ SmiTag(eax);
  __ push(eax);

  // Push the function to invoke on the stack.
  __ push(edi);

  // Try to allocate the object without transitioning into C code. If any of the
  // preconditions is not met, the code bails out to the runtime call.
  Label rt_call, allocated;
  if (FLAG_inline_new) {
    Label undo_allocation;
#ifdef ENABLE_DEBUGGER_SUPPORT
    ExternalReference debug_step_in_fp =
        ExternalReference::debug_step_in_fp_address(masm->isolate());
    __ cmp(Operand::StaticVariable(debug_step_in_fp), Immediate(0));
    __ j(not_equal, &rt_call);
#endif

    // Verified that the constructor is a JSFunction.
    // Load the initial map and verify that it is in fact a map.
    // edi: constructor
    __ mov(eax, FieldOperand(edi, JSFunction::kPrototypeOrInitialMapOffset));
    // Will both indicate a NULL and a Smi
    __ test(eax, Immediate(kSmiTagMask));
    __ j(zero, &rt_call);
    // edi: constructor
    // eax: initial map (if proven valid below)
    __ CmpObjectType(eax, MAP_TYPE, ebx);
    __ j(not_equal, &rt_call);

    // Check that the constructor is not constructing a JSFunction (see comments
    // in Runtime_NewObject in runtime.cc). In which case the initial map's
    // instance type would be JS_FUNCTION_TYPE.
    // edi: constructor
    // eax: initial map
    __ CmpInstanceType(eax, JS_FUNCTION_TYPE);
    __ j(equal, &rt_call);

    if (count_constructions) {
      Label allocate;
      // Decrease generous allocation count.
      __ mov(ecx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
      __ dec_b(FieldOperand(ecx, SharedFunctionInfo::kConstructionCountOffset));
      __ j(not_zero, &allocate);

      __ push(eax);
      __ push(edi);

      __ push(edi);  // constructor
      // The call will replace the stub, so the countdown is only done once.
      __ CallRuntime(Runtime::kFinalizeInstanceSize, 1);

      __ pop(edi);
      __ pop(eax);

      __ bind(&allocate);
    }

    // Now allocate the JSObject on the heap.
    // edi: constructor
    // eax: initial map
    __ movzx_b(edi, FieldOperand(eax, Map::kInstanceSizeOffset));
    __ shl(edi, kPointerSizeLog2);
    __ AllocateInNewSpace(edi, ebx, edi, no_reg, &rt_call, NO_ALLOCATION_FLAGS);
    // Allocated the JSObject, now initialize the fields.
    // eax: initial map
    // ebx: JSObject
    // edi: start of next object
    __ mov(Operand(ebx, JSObject::kMapOffset), eax);
    Factory* factory = masm->isolate()->factory();
    __ mov(ecx, factory->empty_fixed_array());
    __ mov(Operand(ebx, JSObject::kPropertiesOffset), ecx);
    __ mov(Operand(ebx, JSObject::kElementsOffset), ecx);
    // Set extra fields in the newly allocated object.
    // eax: initial map
    // ebx: JSObject
    // edi: start of next object
    { Label loop, entry;
      // To allow for truncation.
      if (count_constructions) {
        __ mov(edx, factory->one_pointer_filler_map());
      } else {
        __ mov(edx, factory->undefined_value());
      }
      __ lea(ecx, Operand(ebx, JSObject::kHeaderSize));
      __ jmp(&entry);
      __ bind(&loop);
      __ mov(Operand(ecx, 0), edx);
      __ add(Operand(ecx), Immediate(kPointerSize));
      __ bind(&entry);
      __ cmp(ecx, Operand(edi));
      __ j(less, &loop);
    }

    // Add the object tag to make the JSObject real, so that we can continue and
    // jump into the continuation code at any time from now on. Any failures
    // need to undo the allocation, so that the heap is in a consistent state
    // and verifiable.
    // eax: initial map
    // ebx: JSObject
    // edi: start of next object
    __ or_(Operand(ebx), Immediate(kHeapObjectTag));

    // Check if a non-empty properties array is needed.
    // Allocate and initialize a FixedArray if it is.
    // eax: initial map
    // ebx: JSObject
    // edi: start of next object
    // Calculate the total number of properties described by the map.
    __ movzx_b(edx, FieldOperand(eax, Map::kUnusedPropertyFieldsOffset));
    __ movzx_b(ecx, FieldOperand(eax, Map::kPreAllocatedPropertyFieldsOffset));
    __ add(edx, Operand(ecx));
    // Calculate unused properties past the end of the in-object properties.
    __ movzx_b(ecx, FieldOperand(eax, Map::kInObjectPropertiesOffset));
    __ sub(edx, Operand(ecx));
    // Done if no extra properties are to be allocated.
    __ j(zero, &allocated);
    __ Assert(positive, "Property allocation count failed.");

    // Scale the number of elements by pointer size and add the header for
    // FixedArrays to the start of the next object calculation from above.
    // ebx: JSObject
    // edi: start of next object (will be start of FixedArray)
    // edx: number of elements in properties array
    __ AllocateInNewSpace(FixedArray::kHeaderSize,
                          times_pointer_size,
                          edx,
                          edi,
                          ecx,
                          no_reg,
                          &undo_allocation,
                          RESULT_CONTAINS_TOP);

    // Initialize the FixedArray.
    // ebx: JSObject
    // edi: FixedArray
    // edx: number of elements
    // ecx: start of next object
    __ mov(eax, factory->fixed_array_map());
    __ mov(Operand(edi, FixedArray::kMapOffset), eax);  // setup the map
    __ SmiTag(edx);
    __ mov(Operand(edi, FixedArray::kLengthOffset), edx);  // and length

    // Initialize the fields to undefined.
    // ebx: JSObject
    // edi: FixedArray
    // ecx: start of next object
    { Label loop, entry;
      __ mov(edx, factory->undefined_value());
      __ lea(eax, Operand(edi, FixedArray::kHeaderSize));
      __ jmp(&entry);
      __ bind(&loop);
      __ mov(Operand(eax, 0), edx);
      __ add(Operand(eax), Immediate(kPointerSize));
      __ bind(&entry);
      __ cmp(eax, Operand(ecx));
      __ j(below, &loop);
    }

    // Store the initialized FixedArray into the properties field of
    // the JSObject
    // ebx: JSObject
    // edi: FixedArray
    __ or_(Operand(edi), Immediate(kHeapObjectTag));  // add the heap tag
    __ mov(FieldOperand(ebx, JSObject::kPropertiesOffset), edi);


    // Continue with JSObject being successfully allocated
    // ebx: JSObject
    __ jmp(&allocated);

    // Undo the setting of the new top so that the heap is verifiable. For
    // example, the map's unused properties potentially do not match the
    // allocated objects unused properties.
    // ebx: JSObject (previous new top)
    __ bind(&undo_allocation);
    __ UndoAllocationInNewSpace(ebx);
  }

  // Allocate the new receiver object using the runtime call.
  __ bind(&rt_call);
  // Must restore edi (constructor) before calling runtime.
  __ mov(edi, Operand(esp, 0));
  // edi: function (constructor)
  __ push(edi);
  __ CallRuntime(Runtime::kNewObject, 1);
  __ mov(ebx, Operand(eax));  // store result in ebx

  // New object allocated.
  // ebx: newly allocated object
  __ bind(&allocated);
  // Retrieve the function from the stack.
  __ pop(edi);

  // Retrieve smi-tagged arguments count from the stack.
  __ mov(eax, Operand(esp, 0));
  __ SmiUntag(eax);

  // Push the allocated receiver to the stack. We need two copies
  // because we may have to return the original one and the calling
  // conventions dictate that the called function pops the receiver.
  __ push(ebx);
  __ push(ebx);

  // Setup pointer to last argument.
  __ lea(ebx, Operand(ebp, StandardFrameConstants::kCallerSPOffset));

  // Copy arguments and receiver to the expression stack.
  Label loop, entry;
  __ mov(ecx, Operand(eax));
  __ jmp(&entry);
  __ bind(&loop);
  __ push(Operand(ebx, ecx, times_4, 0));
  __ bind(&entry);
  __ dec(ecx);
  __ j(greater_equal, &loop);

  // Call the function.
  if (is_api_function) {
    __ mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
    Handle<Code> code =
        masm->isolate()->builtins()->HandleApiCallConstruct();
    ParameterCount expected(0);
    __ InvokeCode(code, expected, expected,
                  RelocInfo::CODE_TARGET, CALL_FUNCTION);
  } else {
    ParameterCount actual(eax);
    __ InvokeFunction(edi, actual, CALL_FUNCTION);
  }

  // Restore context from the frame.
  __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));

  // If the result is an object (in the ECMA sense), we should get rid
  // of the receiver and use the result; see ECMA-262 section 13.2.2-7
  // on page 74.
  Label use_receiver, exit;

  // If the result is a smi, it is *not* an object in the ECMA sense.
  __ test(eax, Immediate(kSmiTagMask));
  __ j(zero, &use_receiver, not_taken);

  // If the type of the result (stored in its map) is less than
  // FIRST_JS_OBJECT_TYPE, it is not an object in the ECMA sense.
  __ CmpObjectType(eax, FIRST_JS_OBJECT_TYPE, ecx);
  __ j(above_equal, &exit, not_taken);

  // Throw away the result of the constructor invocation and use the
  // on-stack receiver as the result.
  __ bind(&use_receiver);
  __ mov(eax, Operand(esp, 0));

  // Restore the arguments count and leave the construct frame.
  __ bind(&exit);
  __ mov(ebx, Operand(esp, kPointerSize));  // get arguments count
  __ LeaveConstructFrame();

  // Remove caller arguments from the stack and return.
  ASSERT(kSmiTagSize == 1 && kSmiTag == 0);
  __ pop(ecx);
  __ lea(esp, Operand(esp, ebx, times_2, 1 * kPointerSize));  // 1 ~ receiver
  __ push(ecx);
  __ IncrementCounter(masm->isolate()->counters()->constructed_objects(), 1);
  __ ret(0);
}


void Builtins::Generate_JSConstructStubCountdown(MacroAssembler* masm) {
  Generate_JSConstructStubHelper(masm, false, true);
}


void Builtins::Generate_JSConstructStubGeneric(MacroAssembler* masm) {
  Generate_JSConstructStubHelper(masm, false, false);
}


void Builtins::Generate_JSConstructStubApi(MacroAssembler* masm) {
  Generate_JSConstructStubHelper(masm, true, false);
}


static void Generate_JSEntryTrampolineHelper(MacroAssembler* masm,
                                             bool is_construct) {
  // Clear the context before we push it when entering the JS frame.
  __ Set(esi, Immediate(0));

  // Enter an internal frame.
  __ EnterInternalFrame();

  // Load the previous frame pointer (ebx) to access C arguments
  __ mov(ebx, Operand(ebp, 0));

  // Get the function from the frame and setup the context.
  __ mov(ecx, Operand(ebx, EntryFrameConstants::kFunctionArgOffset));
  __ mov(esi, FieldOperand(ecx, JSFunction::kContextOffset));

  // Push the function and the receiver onto the stack.
  __ push(ecx);
  __ push(Operand(ebx, EntryFrameConstants::kReceiverArgOffset));

  // Load the number of arguments and setup pointer to the arguments.
  __ mov(eax, Operand(ebx, EntryFrameConstants::kArgcOffset));
  __ mov(ebx, Operand(ebx, EntryFrameConstants::kArgvOffset));

  // Copy arguments to the stack in a loop.
  Label loop, entry;
  __ Set(ecx, Immediate(0));
  __ jmp(&entry);
  __ bind(&loop);
  __ mov(edx, Operand(ebx, ecx, times_4, 0));  // push parameter from argv
  __ push(Operand(edx, 0));  // dereference handle
  __ inc(Operand(ecx));
  __ bind(&entry);
  __ cmp(ecx, Operand(eax));
  __ j(not_equal, &loop);

  // Get the function from the stack and call it.
  __ mov(edi, Operand(esp, eax, times_4, +1 * kPointerSize));  // +1 ~ receiver

  // Invoke the code.
  if (is_construct) {
    __ call(masm->isolate()->builtins()->JSConstructCall(),
            RelocInfo::CODE_TARGET);
  } else {
    ParameterCount actual(eax);
    __ InvokeFunction(edi, actual, CALL_FUNCTION);
  }

  // Exit the JS frame. Notice that this also removes the empty
  // context and the function left on the stack by the code
  // invocation.
  __ LeaveInternalFrame();
  __ ret(1 * kPointerSize);  // remove receiver
}


void Builtins::Generate_JSEntryTrampoline(MacroAssembler* masm) {
  Generate_JSEntryTrampolineHelper(masm, false);
}


void Builtins::Generate_JSConstructEntryTrampoline(MacroAssembler* masm) {
  Generate_JSEntryTrampolineHelper(masm, true);
}


void Builtins::Generate_LazyCompile(MacroAssembler* masm) {
  // Enter an internal frame.
  __ EnterInternalFrame();

  // Push a copy of the function onto the stack.
  __ push(edi);

  __ push(edi);  // Function is also the parameter to the runtime call.
  __ CallRuntime(Runtime::kLazyCompile, 1);
  __ pop(edi);

  // Tear down temporary frame.
  __ LeaveInternalFrame();

  // Do a tail-call of the compiled function.
  __ lea(ecx, FieldOperand(eax, Code::kHeaderSize));
  __ jmp(Operand(ecx));
}


void Builtins::Generate_LazyRecompile(MacroAssembler* masm) {
  // Enter an internal frame.
  __ EnterInternalFrame();

  // Push a copy of the function onto the stack.
  __ push(edi);

  __ push(edi);  // Function is also the parameter to the runtime call.
  __ CallRuntime(Runtime::kLazyRecompile, 1);

  // Restore function and tear down temporary frame.
  __ pop(edi);
  __ LeaveInternalFrame();

  // Do a tail-call of the compiled function.
  __ lea(ecx, FieldOperand(eax, Code::kHeaderSize));
  __ jmp(Operand(ecx));
}


static void Generate_NotifyDeoptimizedHelper(MacroAssembler* masm,
                                             Deoptimizer::BailoutType type) {
  // Enter an internal frame.
  __ EnterInternalFrame();

  // Pass the function and deoptimization type to the runtime system.
  __ push(Immediate(Smi::FromInt(static_cast<int>(type))));
  __ CallRuntime(Runtime::kNotifyDeoptimized, 1);

  // Tear down temporary frame.
  __ LeaveInternalFrame();

  // Get the full codegen state from the stack and untag it.
  __ mov(ecx, Operand(esp, 1 * kPointerSize));
  __ SmiUntag(ecx);

  // Switch on the state.
  NearLabel not_no_registers, not_tos_eax;
  __ cmp(ecx, FullCodeGenerator::NO_REGISTERS);
  __ j(not_equal, &not_no_registers);
  __ ret(1 * kPointerSize);  // Remove state.

  __ bind(&not_no_registers);
  __ mov(eax, Operand(esp, 2 * kPointerSize));
  __ cmp(ecx, FullCodeGenerator::TOS_REG);
  __ j(not_equal, &not_tos_eax);
  __ ret(2 * kPointerSize);  // Remove state, eax.

  __ bind(&not_tos_eax);
  __ Abort("no cases left");
}


void Builtins::Generate_NotifyDeoptimized(MacroAssembler* masm) {
  Generate_NotifyDeoptimizedHelper(masm, Deoptimizer::EAGER);
}


void Builtins::Generate_NotifyLazyDeoptimized(MacroAssembler* masm) {
  Generate_NotifyDeoptimizedHelper(masm, Deoptimizer::LAZY);
}


void Builtins::Generate_NotifyOSR(MacroAssembler* masm) {
  // TODO(kasperl): Do we need to save/restore the XMM registers too?

  // For now, we are relying on the fact that Runtime::NotifyOSR
  // doesn't do any garbage collection which allows us to save/restore
  // the registers without worrying about which of them contain
  // pointers. This seems a bit fragile.
  __ pushad();
  __ EnterInternalFrame();
  __ CallRuntime(Runtime::kNotifyOSR, 0);
  __ LeaveInternalFrame();
  __ popad();
  __ ret(0);
}


void Builtins::Generate_FunctionCall(MacroAssembler* masm) {
  Factory* factory = masm->isolate()->factory();

  // 1. Make sure we have at least one argument.
  { Label done;
    __ test(eax, Operand(eax));
    __ j(not_zero, &done, taken);
    __ pop(ebx);
    __ push(Immediate(factory->undefined_value()));
    __ push(ebx);
    __ inc(eax);
    __ bind(&done);
  }

  // 2. Get the function to call (passed as receiver) from the stack, check
  //    if it is a function.
  Label non_function;
  // 1 ~ return address.
  __ mov(edi, Operand(esp, eax, times_4, 1 * kPointerSize));
  __ test(edi, Immediate(kSmiTagMask));
  __ j(zero, &non_function, not_taken);
  __ CmpObjectType(edi, JS_FUNCTION_TYPE, ecx);
  __ j(not_equal, &non_function, not_taken);


  // 3a. Patch the first argument if necessary when calling a function.
  Label shift_arguments;
  { Label convert_to_object, use_global_receiver, patch_receiver;
    // Change context eagerly in case we need the global receiver.
    __ mov(esi, FieldOperand(edi, JSFunction::kContextOffset));

    // Do not transform the receiver for strict mode functions.
    __ mov(ebx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
    __ test_b(FieldOperand(ebx, SharedFunctionInfo::kStrictModeByteOffset),
              1 << SharedFunctionInfo::kStrictModeBitWithinByte);
    __ j(not_equal, &shift_arguments);

    // Compute the receiver in non-strict mode.
    __ mov(ebx, Operand(esp, eax, times_4, 0));  // First argument.
    __ test(ebx, Immediate(kSmiTagMask));
    __ j(zero, &convert_to_object);

    __ cmp(ebx, factory->null_value());
    __ j(equal, &use_global_receiver);
    __ cmp(ebx, factory->undefined_value());
    __ j(equal, &use_global_receiver);

    // We don't use IsObjectJSObjectType here because we jump on success.
    __ mov(ecx, FieldOperand(ebx, HeapObject::kMapOffset));
    __ movzx_b(ecx, FieldOperand(ecx, Map::kInstanceTypeOffset));
    __ sub(Operand(ecx), Immediate(FIRST_JS_OBJECT_TYPE));
    __ cmp(ecx, LAST_JS_OBJECT_TYPE - FIRST_JS_OBJECT_TYPE);
    __ j(below_equal, &shift_arguments);

    __ bind(&convert_to_object);
    __ EnterInternalFrame();  // In order to preserve argument count.
    __ SmiTag(eax);
    __ push(eax);

    __ push(ebx);
    __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
    __ mov(ebx, eax);

    __ pop(eax);
    __ SmiUntag(eax);
    __ LeaveInternalFrame();
    // Restore the function to edi.
    __ mov(edi, Operand(esp, eax, times_4, 1 * kPointerSize));
    __ jmp(&patch_receiver);

    // Use the global receiver object from the called function as the
    // receiver.
    __ bind(&use_global_receiver);
    const int kGlobalIndex =
        Context::kHeaderSize + Context::GLOBAL_INDEX * kPointerSize;
    __ mov(ebx, FieldOperand(esi, kGlobalIndex));
    __ mov(ebx, FieldOperand(ebx, GlobalObject::kGlobalContextOffset));
    __ mov(ebx, FieldOperand(ebx, kGlobalIndex));
    __ mov(ebx, FieldOperand(ebx, GlobalObject::kGlobalReceiverOffset));

    __ bind(&patch_receiver);
    __ mov(Operand(esp, eax, times_4, 0), ebx);

    __ jmp(&shift_arguments);
  }

  // 3b. Patch the first argument when calling a non-function.  The
  //     CALL_NON_FUNCTION builtin expects the non-function callee as
  //     receiver, so overwrite the first argument which will ultimately
  //     become the receiver.
  __ bind(&non_function);
  __ mov(Operand(esp, eax, times_4, 0), edi);
  // Clear edi to indicate a non-function being called.
  __ Set(edi, Immediate(0));

  // 4. Shift arguments and return address one slot down on the stack
  //    (overwriting the original receiver).  Adjust argument count to make
  //    the original first argument the new receiver.
  __ bind(&shift_arguments);
  { Label loop;
    __ mov(ecx, eax);
    __ bind(&loop);
    __ mov(ebx, Operand(esp, ecx, times_4, 0));
    __ mov(Operand(esp, ecx, times_4, kPointerSize), ebx);
    __ dec(ecx);
    __ j(not_sign, &loop);  // While non-negative (to copy return address).
    __ pop(ebx);  // Discard copy of return address.
    __ dec(eax);  // One fewer argument (first argument is new receiver).
  }

  // 5a. Call non-function via tail call to CALL_NON_FUNCTION builtin.
  { Label function;
    __ test(edi, Operand(edi));
    __ j(not_zero, &function, taken);
    __ Set(ebx, Immediate(0));
    __ GetBuiltinEntry(edx, Builtins::CALL_NON_FUNCTION);
    __ jmp(masm->isolate()->builtins()->ArgumentsAdaptorTrampoline(),
           RelocInfo::CODE_TARGET);
    __ bind(&function);
  }

  // 5b. Get the code to call from the function and check that the number of
  //     expected arguments matches what we're providing.  If so, jump
  //     (tail-call) to the code in register edx without checking arguments.
  __ mov(edx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
  __ mov(ebx,
         FieldOperand(edx, SharedFunctionInfo::kFormalParameterCountOffset));
  __ mov(edx, FieldOperand(edi, JSFunction::kCodeEntryOffset));
  __ SmiUntag(ebx);
  __ cmp(eax, Operand(ebx));
  __ j(not_equal,
       masm->isolate()->builtins()->ArgumentsAdaptorTrampoline());

  ParameterCount expected(0);
  __ InvokeCode(Operand(edx), expected, expected, JUMP_FUNCTION);
}


void Builtins::Generate_FunctionApply(MacroAssembler* masm) {
  __ EnterInternalFrame();

  __ push(Operand(ebp, 4 * kPointerSize));  // push this
  __ push(Operand(ebp, 2 * kPointerSize));  // push arguments
  __ InvokeBuiltin(Builtins::APPLY_PREPARE, CALL_FUNCTION);

  // Check the stack for overflow. We are not trying need to catch
  // interruptions (e.g. debug break and preemption) here, so the "real stack
  // limit" is checked.
  Label okay;
  ExternalReference real_stack_limit =
      ExternalReference::address_of_real_stack_limit(masm->isolate());
  __ mov(edi, Operand::StaticVariable(real_stack_limit));
  // Make ecx the space we have left. The stack might already be overflowed
  // here which will cause ecx to become negative.
  __ mov(ecx, Operand(esp));
  __ sub(ecx, Operand(edi));
  // Make edx the space we need for the array when it is unrolled onto the
  // stack.
  __ mov(edx, Operand(eax));
  __ shl(edx, kPointerSizeLog2 - kSmiTagSize);
  // Check if the arguments will overflow the stack.
  __ cmp(ecx, Operand(edx));
  __ j(greater, &okay, taken);  // Signed comparison.

  // Out of stack space.
  __ push(Operand(ebp, 4 * kPointerSize));  // push this
  __ push(eax);
  __ InvokeBuiltin(Builtins::APPLY_OVERFLOW, CALL_FUNCTION);
  __ bind(&okay);
  // End of stack check.

  // Push current index and limit.
  const int kLimitOffset =
      StandardFrameConstants::kExpressionsOffset - 1 * kPointerSize;
  const int kIndexOffset = kLimitOffset - 1 * kPointerSize;
  __ push(eax);  // limit
  __ push(Immediate(0));  // index

  // Change context eagerly to get the right global object if
  // necessary.
  __ mov(edi, Operand(ebp, 4 * kPointerSize));
  __ mov(esi, FieldOperand(edi, JSFunction::kContextOffset));

  // Compute the receiver.
  Label call_to_object, use_global_receiver, push_receiver;
  __ mov(ebx, Operand(ebp, 3 * kPointerSize));

  // 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, &push_receiver);

  // Compute the receiver in non-strict mode.
  __ test(ebx, Immediate(kSmiTagMask));
  __ j(zero, &call_to_object);
  Factory* factory = masm->isolate()->factory();
  __ cmp(ebx, factory->null_value());
  __ j(equal, &use_global_receiver);
  __ cmp(ebx, factory->undefined_value());
  __ j(equal, &use_global_receiver);

  // If given receiver is already a JavaScript object then there's no
  // reason for converting it.
  // We don't use IsObjectJSObjectType here because we jump on success.
  __ mov(ecx, FieldOperand(ebx, HeapObject::kMapOffset));
  __ movzx_b(ecx, FieldOperand(ecx, Map::kInstanceTypeOffset));
  __ sub(Operand(ecx), Immediate(FIRST_JS_OBJECT_TYPE));
  __ cmp(ecx, LAST_JS_OBJECT_TYPE - FIRST_JS_OBJECT_TYPE);
  __ j(below_equal, &push_receiver);

  // Convert the receiver to an object.
  __ bind(&call_to_object);
  __ push(ebx);
  __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
  __ mov(ebx, Operand(eax));
  __ jmp(&push_receiver);

  // Use the current global receiver object as the receiver.
  __ bind(&use_global_receiver);
  const int kGlobalOffset =
      Context::kHeaderSize + Context::GLOBAL_INDEX * kPointerSize;
  __ mov(ebx, FieldOperand(esi, kGlobalOffset));
  __ mov(ebx, FieldOperand(ebx, GlobalObject::kGlobalContextOffset));
  __ mov(ebx, FieldOperand(ebx, kGlobalOffset));
  __ mov(ebx, FieldOperand(ebx, GlobalObject::kGlobalReceiverOffset));

  // Push the receiver.
  __ bind(&push_receiver);
  __ push(ebx);

  // Copy all arguments from the array to the stack.
  Label entry, loop;
  __ mov(eax, Operand(ebp, kIndexOffset));
  __ jmp(&entry);
  __ bind(&loop);
  __ mov(edx, Operand(ebp, 2 * kPointerSize));  // load arguments

  // Use inline caching to speed up access to arguments.
  Handle<Code> ic = masm->isolate()->builtins()->KeyedLoadIC_Initialize();
  __ call(ic, RelocInfo::CODE_TARGET);
  // It is important that we do not have a test instruction after the
  // call.  A test instruction after the call is used to indicate that
  // we have generated an inline version of the keyed load.  In this
  // case, we know that we are not generating a test instruction next.

  // Push the nth argument.
  __ push(eax);

  // Update the index on the stack and in register eax.
  __ mov(eax, Operand(ebp, kIndexOffset));
  __ add(Operand(eax), Immediate(1 << kSmiTagSize));
  __ mov(Operand(ebp, kIndexOffset), eax);

  __ bind(&entry);
  __ cmp(eax, Operand(ebp, kLimitOffset));
  __ j(not_equal, &loop);

  // Invoke the function.
  ParameterCount actual(eax);
  __ SmiUntag(eax);
  __ mov(edi, Operand(ebp, 4 * kPointerSize));
  __ InvokeFunction(edi, actual, CALL_FUNCTION);

  __ LeaveInternalFrame();
  __ ret(3 * kPointerSize);  // remove this, receiver, and arguments
}


// Number of empty elements to allocate for an empty array.
static const int kPreallocatedArrayElements = 4;


// Allocate an empty JSArray. The allocated array is put into the result
// register. If the parameter initial_capacity is larger than zero an elements
// backing store is allocated with this size and filled with the hole values.
// Otherwise the elements backing store is set to the empty FixedArray.
static void AllocateEmptyJSArray(MacroAssembler* masm,
                                 Register array_function,
                                 Register result,
                                 Register scratch1,
                                 Register scratch2,
                                 Register scratch3,
                                 int initial_capacity,
                                 Label* gc_required) {
  ASSERT(initial_capacity >= 0);

  // Load the initial map from the array function.
  __ mov(scratch1, FieldOperand(array_function,
                                JSFunction::kPrototypeOrInitialMapOffset));

  // Allocate the JSArray object together with space for a fixed array with the
  // requested elements.
  int size = JSArray::kSize;
  if (initial_capacity > 0) {
    size += FixedArray::SizeFor(initial_capacity);
  }
  __ AllocateInNewSpace(size,
                        result,
                        scratch2,
                        scratch3,
                        gc_required,
                        TAG_OBJECT);

  // Allocated the JSArray. Now initialize the fields except for the elements
  // array.
  // result: JSObject
  // scratch1: initial map
  // scratch2: start of next object
  __ mov(FieldOperand(result, JSObject::kMapOffset), scratch1);
  Factory* factory = masm->isolate()->factory();
  __ mov(FieldOperand(result, JSArray::kPropertiesOffset),
         factory->empty_fixed_array());
  // Field JSArray::kElementsOffset is initialized later.
  __ mov(FieldOperand(result, JSArray::kLengthOffset), Immediate(0));

  // If no storage is requested for the elements array just set the empty
  // fixed array.
  if (initial_capacity == 0) {
    __ mov(FieldOperand(result, JSArray::kElementsOffset),
           factory->empty_fixed_array());
    return;
  }

  // Calculate the location of the elements array and set elements array member
  // of the JSArray.
  // result: JSObject
  // scratch2: start of next object
  __ lea(scratch1, Operand(result, JSArray::kSize));
  __ mov(FieldOperand(result, JSArray::kElementsOffset), scratch1);

  // Initialize the FixedArray and fill it with holes. FixedArray length is
  // stored as a smi.
  // result: JSObject
  // scratch1: elements array
  // scratch2: start of next object
  __ mov(FieldOperand(scratch1, FixedArray::kMapOffset),
         factory->fixed_array_map());
  __ mov(FieldOperand(scratch1, FixedArray::kLengthOffset),
         Immediate(Smi::FromInt(initial_capacity)));

  // Fill the FixedArray with the hole value. Inline the code if short.
  // Reconsider loop unfolding if kPreallocatedArrayElements gets changed.
  static const int kLoopUnfoldLimit = 4;
  ASSERT(kPreallocatedArrayElements <= kLoopUnfoldLimit);
  if (initial_capacity <= kLoopUnfoldLimit) {
    // Use a scratch register here to have only one reloc info when unfolding
    // the loop.
    __ mov(scratch3, factory->the_hole_value());
    for (int i = 0; i < initial_capacity; i++) {
      __ mov(FieldOperand(scratch1,
                          FixedArray::kHeaderSize + i * kPointerSize),
             scratch3);
    }
  } else {
    Label loop, entry;
    __ jmp(&entry);
    __ bind(&loop);
    __ mov(Operand(scratch1, 0), factory->the_hole_value());
    __ add(Operand(scratch1), Immediate(kPointerSize));
    __ bind(&entry);
    __ cmp(scratch1, Operand(scratch2));
    __ j(below, &loop);
  }
}


// Allocate a JSArray with the number of elements stored in a register. The
// register array_function holds the built-in Array function and the register
// array_size holds the size of the array as a smi. The allocated array is put
// into the result register and beginning and end of the FixedArray elements
// storage is put into registers elements_array and elements_array_end  (see
// below for when that is not the case). If the parameter fill_with_holes is
// true the allocated elements backing store is filled with the hole values
// otherwise it is left uninitialized. When the backing store is filled the
// register elements_array is scratched.
static void AllocateJSArray(MacroAssembler* masm,
                            Register array_function,  // Array function.
                            Register array_size,  // As a smi, cannot be 0.
                            Register result,
                            Register elements_array,
                            Register elements_array_end,
                            Register scratch,
                            bool fill_with_hole,
                            Label* gc_required) {
  ASSERT(scratch.is(edi));  // rep stos destination
  ASSERT(!fill_with_hole || array_size.is(ecx));  // rep stos count
  ASSERT(!fill_with_hole || !result.is(eax));  // result is never eax

  // Load the initial map from the array function.
  __ mov(elements_array,
         FieldOperand(array_function,
                      JSFunction::kPrototypeOrInitialMapOffset));

  // Allocate the JSArray object together with space for a FixedArray with the
  // requested elements.
  ASSERT(kSmiTagSize == 1 && kSmiTag == 0);
  __ AllocateInNewSpace(JSArray::kSize + FixedArray::kHeaderSize,
                        times_half_pointer_size,  // array_size is a smi.
                        array_size,
                        result,
                        elements_array_end,
                        scratch,
                        gc_required,
                        TAG_OBJECT);

  // Allocated the JSArray. Now initialize the fields except for the elements
  // array.
  // result: JSObject
  // elements_array: initial map
  // elements_array_end: start of next object
  // array_size: size of array (smi)
  __ mov(FieldOperand(result, JSObject::kMapOffset), elements_array);
  Factory* factory = masm->isolate()->factory();
  __ mov(elements_array, factory->empty_fixed_array());
  __ mov(FieldOperand(result, JSArray::kPropertiesOffset), elements_array);
  // Field JSArray::kElementsOffset is initialized later.
  __ mov(FieldOperand(result, JSArray::kLengthOffset), array_size);

  // Calculate the location of the elements array and set elements array member
  // of the JSArray.
  // result: JSObject
  // elements_array_end: start of next object
  // array_size: size of array (smi)
  __ lea(elements_array, Operand(result, JSArray::kSize));
  __ mov(FieldOperand(result, JSArray::kElementsOffset), elements_array);

  // Initialize the fixed array. FixedArray length is stored as a smi.
  // result: JSObject
  // elements_array: elements array
  // elements_array_end: start of next object
  // array_size: size of array (smi)
  __ mov(FieldOperand(elements_array, FixedArray::kMapOffset),
         factory->fixed_array_map());
  // For non-empty JSArrays the length of the FixedArray and the JSArray is the
  // same.
  __ mov(FieldOperand(elements_array, FixedArray::kLengthOffset), array_size);

  // Fill the allocated FixedArray with the hole value if requested.
  // result: JSObject
  // elements_array: elements array
  if (fill_with_hole) {
    __ SmiUntag(array_size);
    __ lea(edi, Operand(elements_array,
                        FixedArray::kHeaderSize - kHeapObjectTag));
    __ mov(eax, factory->the_hole_value());
    __ cld();
    // Do not use rep stos when filling less than kRepStosThreshold
    // words.
    const int kRepStosThreshold = 16;
    Label loop, entry, done;
    __ cmp(ecx, kRepStosThreshold);
    __ j(below, &loop);  // Note: ecx > 0.
    __ rep_stos();
    __ jmp(&done);
    __ bind(&loop);
    __ stos();
    __ bind(&entry);
    __ cmp(edi, Operand(elements_array_end));
    __ j(below, &loop);
    __ bind(&done);
  }
}


// Create a new array for the built-in Array function. This function allocates
// the JSArray object and the FixedArray elements array and initializes these.
// If the Array cannot be constructed in native code the runtime is called. This
// function assumes the following state:
//   edi: constructor (built-in Array function)
//   eax: argc
//   esp[0]: return address
//   esp[4]: last argument
// This function is used for both construct and normal calls of Array. Whether
// it is a construct call or not is indicated by the construct_call parameter.
// The only difference between handling a construct call and a normal call is
// that for a construct call the constructor function in edi needs to be
// preserved for entering the generic code. In both cases argc in eax needs to
// be preserved.
static void ArrayNativeCode(MacroAssembler* masm,
                            bool construct_call,
                            Label* call_generic_code) {
  Label argc_one_or_more, argc_two_or_more, prepare_generic_code_call,
        empty_array, not_empty_array;

  // Push the constructor and argc. No need to tag argc as a smi, as there will
  // be no garbage collection with this on the stack.
  int push_count = 0;
  if (construct_call) {
    push_count++;
    __ push(edi);
  }
  push_count++;
  __ push(eax);

  // Check for array construction with zero arguments.
  __ test(eax, Operand(eax));
  __ j(not_zero, &argc_one_or_more);

  __ bind(&empty_array);
  // Handle construction of an empty array.
  AllocateEmptyJSArray(masm,
                       edi,
                       eax,
                       ebx,
                       ecx,
                       edi,
                       kPreallocatedArrayElements,
                       &prepare_generic_code_call);
  __ IncrementCounter(masm->isolate()->counters()->array_function_native(), 1);
  __ pop(ebx);
  if (construct_call) {
    __ pop(edi);
  }
  __ ret(kPointerSize);

  // Check for one argument. Bail out if argument is not smi or if it is
  // negative.
  __ bind(&argc_one_or_more);
  __ cmp(eax, 1);
  __ j(not_equal, &argc_two_or_more);
  ASSERT(kSmiTag == 0);
  __ mov(ecx, Operand(esp, (push_count + 1) * kPointerSize));
  __ test(ecx, Operand(ecx));
  __ j(not_zero, &not_empty_array);

  // The single argument passed is zero, so we jump to the code above used to
  // handle the case of no arguments passed. To adapt the stack for that we move
  // the return address and the pushed constructor (if pushed) one stack slot up
  // thereby removing the passed argument. Argc is also on the stack - at the
  // bottom - and it needs to be changed from 1 to 0 to have the call into the
  // runtime system work in case a GC is required.
  for (int i = push_count; i > 0; i--) {
    __ mov(eax, Operand(esp, i * kPointerSize));
    __ mov(Operand(esp, (i + 1) * kPointerSize), eax);
  }
  __ add(Operand(esp), Immediate(2 * kPointerSize));  // Drop two stack slots.
  __ push(Immediate(0));  // Treat this as a call with argc of zero.
  __ jmp(&empty_array);

  __ bind(&not_empty_array);
  __ test(ecx, Immediate(kIntptrSignBit | kSmiTagMask));
  __ j(not_zero, &prepare_generic_code_call);

  // Handle construction of an empty array of a certain size. Get the size from
  // the stack and bail out if size is to large to actually allocate an elements
  // array.
  __ cmp(ecx, JSObject::kInitialMaxFastElementArray << kSmiTagSize);
  __ j(greater_equal, &prepare_generic_code_call);

  // edx: array_size (smi)
  // edi: constructor
  // esp[0]: argc (cannot be 0 here)
  // esp[4]: constructor (only if construct_call)
  // esp[8]: return address
  // esp[C]: argument
  AllocateJSArray(masm,
                  edi,
                  ecx,
                  ebx,
                  eax,
                  edx,
                  edi,
                  true,
                  &prepare_generic_code_call);
  Counters* counters = masm->isolate()->counters();
  __ IncrementCounter(counters->array_function_native(), 1);
  __ mov(eax, ebx);
  __ pop(ebx);
  if (construct_call) {
    __ pop(edi);
  }
  __ ret(2 * kPointerSize);

  // Handle construction of an array from a list of arguments.
  __ bind(&argc_two_or_more);
  ASSERT(kSmiTag == 0);
  __ SmiTag(eax);  // Convet argc to a smi.
  // eax: array_size (smi)
  // edi: constructor
  // esp[0] : argc
  // esp[4]: constructor (only if construct_call)
  // esp[8] : return address
  // esp[C] : last argument
  AllocateJSArray(masm,
                  edi,
                  eax,
                  ebx,
                  ecx,
                  edx,
                  edi,
                  false,
                  &prepare_generic_code_call);
  __ IncrementCounter(counters->array_function_native(), 1);
  __ mov(eax, ebx);
  __ pop(ebx);
  if (construct_call) {
    __ pop(edi);
  }
  __ push(eax);
  // eax: JSArray
  // ebx: argc
  // edx: elements_array_end (untagged)
  // esp[0]: JSArray
  // esp[4]: return address
  // esp[8]: last argument

  // Location of the last argument
  __ lea(edi, Operand(esp, 2 * kPointerSize));

  // Location of the first array element (Parameter fill_with_holes to
  // AllocateJSArrayis false, so the FixedArray is returned in ecx).
  __ lea(edx, Operand(ecx, FixedArray::kHeaderSize - kHeapObjectTag));

  // ebx: argc
  // edx: location of the first array element
  // edi: location of the last argument
  // esp[0]: JSArray
  // esp[4]: return address
  // esp[8]: last argument
  Label loop, entry;
  __ mov(ecx, ebx);
  __ jmp(&entry);
  __ bind(&loop);
  __ mov(eax, Operand(edi, ecx, times_pointer_size, 0));
  __ mov(Operand(edx, 0), eax);
  __ add(Operand(edx), Immediate(kPointerSize));
  __ bind(&entry);
  __ dec(ecx);
  __ j(greater_equal, &loop);

  // Remove caller arguments from the stack and return.
  // ebx: argc
  // esp[0]: JSArray
  // esp[4]: return address
  // esp[8]: last argument
  __ pop(eax);
  __ pop(ecx);
  __ lea(esp, Operand(esp, ebx, times_pointer_size, 1 * kPointerSize));
  __ push(ecx);
  __ ret(0);

  // Restore argc and constructor before running the generic code.
  __ bind(&prepare_generic_code_call);
  __ pop(eax);
  if (construct_call) {
    __ pop(edi);
  }
  __ jmp(call_generic_code);
}


void Builtins::Generate_ArrayCode(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- eax : argc
  //  -- esp[0] : return address
  //  -- esp[4] : last argument
  // -----------------------------------
  Label generic_array_code;

  // Get the Array function.
  __ LoadGlobalFunction(Context::ARRAY_FUNCTION_INDEX, edi);

  if (FLAG_debug_code) {
    // Initial map for the builtin Array function shoud be a map.
    __ mov(ebx, FieldOperand(edi, JSFunction::kPrototypeOrInitialMapOffset));
    // Will both indicate a NULL and a Smi.
    __ test(ebx, Immediate(kSmiTagMask));
    __ Assert(not_zero, "Unexpected initial map for Array function");
    __ CmpObjectType(ebx, MAP_TYPE, ecx);
    __ Assert(equal, "Unexpected initial map for Array function");
  }

  // Run the native code for the Array function called as a normal function.
  ArrayNativeCode(masm, false, &generic_array_code);

  // Jump to the generic array code in case the specialized code cannot handle
  // the construction.
  __ bind(&generic_array_code);
  Handle<Code> array_code =
      masm->isolate()->builtins()->ArrayCodeGeneric();
  __ jmp(array_code, RelocInfo::CODE_TARGET);
}


void Builtins::Generate_ArrayConstructCode(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- eax : argc
  //  -- edi : constructor
  //  -- esp[0] : return address
  //  -- esp[4] : last argument
  // -----------------------------------
  Label generic_constructor;

  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(ebx, FieldOperand(edi, JSFunction::kPrototypeOrInitialMapOffset));
    // Will both indicate a NULL and a Smi.
    __ test(ebx, Immediate(kSmiTagMask));
    __ Assert(not_zero, "Unexpected initial map for Array function");
    __ CmpObjectType(ebx, MAP_TYPE, ecx);
    __ Assert(equal, "Unexpected initial map for Array function");
  }

  // Run the native code for the Array function called as constructor.
  ArrayNativeCode(masm, true, &generic_constructor);

  // Jump to the generic construct code in case the specialized code cannot
  // handle the construction.
  __ bind(&generic_constructor);
  Handle<Code> generic_construct_stub =
      masm->isolate()->builtins()->JSConstructStubGeneric();
  __ jmp(generic_construct_stub, RelocInfo::CODE_TARGET);
}


void Builtins::Generate_StringConstructCode(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- eax                 : number of arguments
  //  -- edi                 : constructor function
  //  -- esp[0]              : return address
  //  -- esp[(argc - n) * 4] : arg[n] (zero-based)
  //  -- esp[(argc + 1) * 4] : receiver
  // -----------------------------------
  Counters* counters = masm->isolate()->counters();
  __ IncrementCounter(counters->string_ctor_calls(), 1);

  if (FLAG_debug_code) {
    __ LoadGlobalFunction(Context::STRING_FUNCTION_INDEX, ecx);
    __ cmp(edi, Operand(ecx));
    __ Assert(equal, "Unexpected String function");
  }

  // Load the first argument into eax and get rid of the rest
  // (including the receiver).
  Label no_arguments;
  __ test(eax, Operand(eax));
  __ j(zero, &no_arguments);
  __ mov(ebx, Operand(esp, eax, times_pointer_size, 0));
  __ pop(ecx);
  __ lea(esp, Operand(esp, eax, times_pointer_size, kPointerSize));
  __ push(ecx);
  __ mov(eax, ebx);

  // Lookup the argument in the number to string cache.
  Label not_cached, argument_is_string;
  NumberToStringStub::GenerateLookupNumberStringCache(
      masm,
      eax,  // Input.
      ebx,  // Result.
      ecx,  // Scratch 1.
      edx,  // Scratch 2.
      false,  // Input is known to be smi?
      &not_cached);
  __ IncrementCounter(counters->string_ctor_cached_number(), 1);
  __ bind(&argument_is_string);
  // ----------- S t a t e -------------
  //  -- ebx    : argument converted to string
  //  -- edi    : constructor function
  //  -- esp[0] : return address
  // -----------------------------------

  // Allocate a JSValue and put the tagged pointer into eax.
  Label gc_required;
  __ AllocateInNewSpace(JSValue::kSize,
                        eax,  // Result.
                        ecx,  // New allocation top (we ignore it).
                        no_reg,
                        &gc_required,
                        TAG_OBJECT);

  // Set the map.
  __ LoadGlobalFunctionInitialMap(edi, ecx);
  if (FLAG_debug_code) {
    __ cmpb(FieldOperand(ecx, Map::kInstanceSizeOffset),
            JSValue::kSize >> kPointerSizeLog2);
    __ Assert(equal, "Unexpected string wrapper instance size");
    __ cmpb(FieldOperand(ecx, Map::kUnusedPropertyFieldsOffset), 0);
    __ Assert(equal, "Unexpected unused properties of string wrapper");
  }
  __ mov(FieldOperand(eax, HeapObject::kMapOffset), ecx);

  // Set properties and elements.
  Factory* factory = masm->isolate()->factory();
  __ Set(ecx, Immediate(factory->empty_fixed_array()));
  __ mov(FieldOperand(eax, JSObject::kPropertiesOffset), ecx);
  __ mov(FieldOperand(eax, JSObject::kElementsOffset), ecx);

  // Set the value.
  __ mov(FieldOperand(eax, JSValue::kValueOffset), ebx);

  // Ensure the object is fully initialized.
  STATIC_ASSERT(JSValue::kSize == 4 * kPointerSize);

  // We're done. Return.
  __ ret(0);

  // The argument was not found in the number to string cache. Check
  // if it's a string already before calling the conversion builtin.
  Label convert_argument;
  __ bind(&not_cached);
  STATIC_ASSERT(kSmiTag == 0);
  __ test(eax, Immediate(kSmiTagMask));
  __ j(zero, &convert_argument);
  Condition is_string = masm->IsObjectStringType(eax, ebx, ecx);
  __ j(NegateCondition(is_string), &convert_argument);
  __ mov(ebx, eax);
  __ IncrementCounter(counters->string_ctor_string_value(), 1);
  __ jmp(&argument_is_string);

  // Invoke the conversion builtin and put the result into ebx.
  __ bind(&convert_argument);
  __ IncrementCounter(counters->string_ctor_conversions(), 1);
  __ EnterInternalFrame();
  __ push(edi);  // Preserve the function.
  __ push(eax);
  __ InvokeBuiltin(Builtins::TO_STRING, CALL_FUNCTION);
  __ pop(edi);
  __ LeaveInternalFrame();
  __ mov(ebx, eax);
  __ jmp(&argument_is_string);

  // Load the empty string into ebx, remove the receiver from the
  // stack, and jump back to the case where the argument is a string.
  __ bind(&no_arguments);
  __ Set(ebx, Immediate(factory->empty_string()));
  __ pop(ecx);
  __ lea(esp, Operand(esp, kPointerSize));
  __ push(ecx);
  __ jmp(&argument_is_string);

  // At this point the argument is already a string. Call runtime to
  // create a string wrapper.
  __ bind(&gc_required);
  __ IncrementCounter(counters->string_ctor_gc_required(), 1);
  __ EnterInternalFrame();
  __ push(ebx);
  __ CallRuntime(Runtime::kNewStringWrapper, 1);
  __ LeaveInternalFrame();
  __ ret(0);
}


static void EnterArgumentsAdaptorFrame(MacroAssembler* masm) {
  __ push(ebp);
  __ mov(ebp, Operand(esp));

  // Store the arguments adaptor context sentinel.
  __ push(Immediate(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));

  // Push the function on the stack.
  __ push(edi);

  // Preserve the number of arguments on the stack. Must preserve both
  // eax and ebx because these registers are used when copying the
  // arguments and the receiver.
  ASSERT(kSmiTagSize == 1);
  __ lea(ecx, Operand(eax, eax, times_1, kSmiTag));
  __ push(ecx);
}


static void LeaveArgumentsAdaptorFrame(MacroAssembler* masm) {
  // Retrieve the number of arguments from the stack.
  __ mov(ebx, Operand(ebp, ArgumentsAdaptorFrameConstants::kLengthOffset));

  // Leave the frame.
  __ leave();

  // Remove caller arguments from the stack.
  ASSERT(kSmiTagSize == 1 && kSmiTag == 0);
  __ pop(ecx);
  __ lea(esp, Operand(esp, ebx, times_2, 1 * kPointerSize));  // 1 ~ receiver
  __ push(ecx);
}


void Builtins::Generate_ArgumentsAdaptorTrampoline(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- eax : actual number of arguments
  //  -- ebx : expected number of arguments
  //  -- edx : code entry to call
  // -----------------------------------

  Label invoke, dont_adapt_arguments;
  __ IncrementCounter(masm->isolate()->counters()->arguments_adaptors(), 1);

  Label enough, too_few;
  __ cmp(eax, Operand(ebx));
  __ j(less, &too_few);
  __ cmp(ebx, SharedFunctionInfo::kDontAdaptArgumentsSentinel);
  __ j(equal, &dont_adapt_arguments);

  {  // Enough parameters: Actual >= expected.
    __ bind(&enough);
    EnterArgumentsAdaptorFrame(masm);

    // Copy receiver and all expected arguments.
    const int offset = StandardFrameConstants::kCallerSPOffset;
    __ lea(eax, Operand(ebp, eax, times_4, offset));
    __ mov(ecx, -1);  // account for receiver

    Label copy;
    __ bind(&copy);
    __ inc(ecx);
    __ push(Operand(eax, 0));
    __ sub(Operand(eax), Immediate(kPointerSize));
    __ cmp(ecx, Operand(ebx));
    __ j(less, &copy);
    __ jmp(&invoke);
  }

  {  // Too few parameters: Actual < expected.
    __ bind(&too_few);
    EnterArgumentsAdaptorFrame(masm);

    // Copy receiver and all actual arguments.
    const int offset = StandardFrameConstants::kCallerSPOffset;
    __ lea(edi, Operand(ebp, eax, times_4, offset));
    __ mov(ecx, -1);  // account for receiver

    Label copy;
    __ bind(&copy);
    __ inc(ecx);
    __ push(Operand(edi, 0));
    __ sub(Operand(edi), Immediate(kPointerSize));
    __ cmp(ecx, Operand(eax));
    __ j(less, &copy);

    // Fill remaining expected arguments with undefined values.
    Label fill;
    __ bind(&fill);
    __ inc(ecx);
    __ push(Immediate(masm->isolate()->factory()->undefined_value()));
    __ cmp(ecx, Operand(ebx));
    __ j(less, &fill);

    // Restore function pointer.
    __ mov(edi, Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
  }

  // Call the entry point.
  __ bind(&invoke);
  __ call(Operand(edx));

  // Leave frame and return.
  LeaveArgumentsAdaptorFrame(masm);
  __ ret(0);

  // -------------------------------------------
  // Dont adapt arguments.
  // -------------------------------------------
  __ bind(&dont_adapt_arguments);
  __ jmp(Operand(edx));
}


void Builtins::Generate_OnStackReplacement(MacroAssembler* masm) {
  // We shouldn't be performing on-stack replacement in the first
  // place if the CPU features we need for the optimized Crankshaft
  // code aren't supported.
  CpuFeatures* cpu_features = masm->isolate()->cpu_features();
  cpu_features->Probe(false);
  if (!cpu_features->IsSupported(SSE2)) {
    __ Abort("Unreachable code: Cannot optimize without SSE2 support.");
    return;
  }

  // Get the loop depth of the stack guard check. This is recorded in
  // a test(eax, depth) instruction right after the call.
  Label stack_check;
  __ mov(ebx, Operand(esp, 0));  // return address
  if (FLAG_debug_code) {
    __ cmpb(Operand(ebx, 0), Assembler::kTestAlByte);
    __ Assert(equal, "test eax instruction not found after loop stack check");
  }
  __ movzx_b(ebx, Operand(ebx, 1));  // depth

  // Get the loop nesting level at which we allow OSR from the
  // unoptimized code and check if we want to do OSR yet. If not we
  // should perform a stack guard check so we can get interrupts while
  // waiting for on-stack replacement.
  __ mov(eax, Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
  __ mov(ecx, FieldOperand(eax, JSFunction::kSharedFunctionInfoOffset));
  __ mov(ecx, FieldOperand(ecx, SharedFunctionInfo::kCodeOffset));
  __ cmpb(ebx, FieldOperand(ecx, Code::kAllowOSRAtLoopNestingLevelOffset));
  __ j(greater, &stack_check);

  // Pass the function to optimize as the argument to the on-stack
  // replacement runtime function.
  __ EnterInternalFrame();
  __ push(eax);
  __ CallRuntime(Runtime::kCompileForOnStackReplacement, 1);
  __ LeaveInternalFrame();

  // If the result was -1 it means that we couldn't optimize the
  // function. Just return and continue in the unoptimized version.
  NearLabel skip;
  __ cmp(Operand(eax), Immediate(Smi::FromInt(-1)));
  __ j(not_equal, &skip);
  __ ret(0);

  // If we decide not to perform on-stack replacement we perform a
  // stack guard check to enable interrupts.
  __ bind(&stack_check);
  NearLabel ok;
  ExternalReference stack_limit =
      ExternalReference::address_of_stack_limit(masm->isolate());
  __ cmp(esp, Operand::StaticVariable(stack_limit));
  __ j(above_equal, &ok, taken);
  StackCheckStub stub;
  __ TailCallStub(&stub);
  __ Abort("Unreachable code: returned from tail call.");
  __ bind(&ok);
  __ ret(0);

  __ bind(&skip);
  // Untag the AST id and push it on the stack.
  __ SmiUntag(eax);
  __ push(eax);

  // Generate the code for doing the frame-to-frame translation using
  // the deoptimizer infrastructure.
  Deoptimizer::EntryGenerator generator(masm, Deoptimizer::OSR);
  generator.Generate();
}


#undef __
}
}  // namespace v8::internal

#endif  // V8_TARGET_ARCH_IA32