CSE2410 Fall 2014 Bounce

// Copyright 2012 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

// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "v8.h"

#if V8_TARGET_ARCH_IA32

#include "ic-inl.h"

#include "codegen.h"

#include "stub-cache.h"

namespace v8 {

namespace internal {

#define __ ACCESS_MASM(masm)

static void ProbeTable(Isolate* isolate,

                       MacroAssembler* masm,

                       Code::Flags flags,

                       StubCache::Table table,

                       Register name,

                       Register receiver,

                       // Number of the cache entry pointer-size scaled.

                       Register offset,

                       Register extra) {

  ExternalReference key_offset(isolate->stub_cache()->key_reference(table));

  ExternalReference value_offset(isolate->stub_cache()->value_reference(table));

  ExternalReference map_offset(isolate->stub_cache()->map_reference(table));

  Label miss;

  // Multiply by 3 because there are 3 fields per entry (name, code, map).

  __ lea(offset, Operand(offset, offset, times_2, 0));

  if (extra.is_valid()) {

    // Get the code entry from the cache.

    __ mov(extra, Operand::StaticArray(offset, times_1, value_offset));

    // Check that the key in the entry matches the name.

    __ cmp(name, Operand::StaticArray(offset, times_1, key_offset));

    __ j(not_equal, &miss);

    // Check the map matches.

    __ mov(offset, Operand::StaticArray(offset, times_1, map_offset));

    __ cmp(offset, FieldOperand(receiver, HeapObject::kMapOffset));

    __ j(not_equal, &miss);

    // Check that the flags match what we're looking for.

    __ mov(offset, FieldOperand(extra, Code::kFlagsOffset));

    __ and_(offset, ~Code::kFlagsNotUsedInLookup);

    __ cmp(offset, flags);

    __ j(not_equal, &miss);

#ifdef DEBUG

    if (FLAG_test_secondary_stub_cache && table == StubCache::kPrimary) {

      __ jmp(&miss);

    } else if (FLAG_test_primary_stub_cache && table == StubCache::kSecondary) {

      __ jmp(&miss);

    }

#endif

    // Jump to the first instruction in the code stub.

    __ add(extra, Immediate(Code::kHeaderSize - kHeapObjectTag));

    __ jmp(extra);

    __ bind(&miss);

  } else {

    // Save the offset on the stack.

    __ push(offset);

    // Check that the key in the entry matches the name.

    __ cmp(name, Operand::StaticArray(offset, times_1, key_offset));

    __ j(not_equal, &miss);

    // Check the map matches.

    __ mov(offset, Operand::StaticArray(offset, times_1, map_offset));

    __ cmp(offset, FieldOperand(receiver, HeapObject::kMapOffset));

    __ j(not_equal, &miss);

    // Restore offset register.

    __ mov(offset, Operand(esp, 0));

    // Get the code entry from the cache.

    __ mov(offset, Operand::StaticArray(offset, times_1, value_offset));

    // Check that the flags match what we're looking for.

    __ mov(offset, FieldOperand(offset, Code::kFlagsOffset));

    __ and_(offset, ~Code::kFlagsNotUsedInLookup);

    __ cmp(offset, flags);

    __ j(not_equal, &miss);

#ifdef DEBUG

    if (FLAG_test_secondary_stub_cache && table == StubCache::kPrimary) {

      __ jmp(&miss);

    } else if (FLAG_test_primary_stub_cache && table == StubCache::kSecondary) {

      __ jmp(&miss);

    }

#endif

    // Restore offset and re-load code entry from cache.

    __ pop(offset);

    __ mov(offset, Operand::StaticArray(offset, times_1, value_offset));

    // Jump to the first instruction in the code stub.

    __ add(offset, Immediate(Code::kHeaderSize - kHeapObjectTag));

    __ jmp(offset);

    // Pop at miss.

    __ bind(&miss);

    __ pop(offset);

  }

}

// 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 unique and receiver must be a heap object.

static void GenerateDictionaryNegativeLookup(MacroAssembler* masm,

                                             Label* miss_label,

                                             Register receiver,

                                             Handle<Name> name,

                                             Register r0,

                                             Register r1) {

  ASSERT(name->IsUniqueName());

  Counters* counters = masm->isolate()->counters();

  __ IncrementCounter(counters->negative_lookups(), 1);

  __ IncrementCounter(counters->negative_lookups_miss(), 1);

  __ mov(r0, FieldOperand(receiver, HeapObject::kMapOffset));

  const int kInterceptorOrAccessCheckNeededMask =

      (1 << Map::kHasNamedInterceptor) | (1 << Map::kIsAccessCheckNeeded);

  // Bail out if the receiver has a named interceptor or requires access checks.

  __ test_b(FieldOperand(r0, Map::kBitFieldOffset),

            kInterceptorOrAccessCheckNeededMask);

  __ j(not_zero, miss_label);

  // Check that receiver is a JSObject.

  __ CmpInstanceType(r0, FIRST_SPEC_OBJECT_TYPE);

  __ j(below, miss_label);

  // Load properties array.

  Register properties = r0;

  __ mov(properties, FieldOperand(receiver, JSObject::kPropertiesOffset));

  // Check that the properties array is a dictionary.

  __ cmp(FieldOperand(properties, HeapObject::kMapOffset),

         Immediate(masm->isolate()->factory()->hash_table_map()));

  __ j(not_equal, miss_label);

  Label done;

  NameDictionaryLookupStub::GenerateNegativeLookup(masm,

                                                   miss_label,

                                                   &done,

                                                   properties,

                                                   name,

                                                   r1);

  __ bind(&done);

  __ DecrementCounter(counters->negative_lookups_miss(), 1);

}

void StubCache::GenerateProbe(MacroAssembler* masm,

                              Code::Flags flags,

                              Register receiver,

                              Register name,

                              Register scratch,

                              Register extra,

                              Register extra2,

                              Register extra3) {

  Label miss;

  // Assert that code is valid.  The multiplying code relies on the entry size

  // being 12.

  ASSERT(sizeof(Entry) == 12);

  // Assert the flags do not name a specific type.

  ASSERT(Code::ExtractTypeFromFlags(flags) == 0);

  // Assert that there are no register conflicts.

  ASSERT(!scratch.is(receiver));

  ASSERT(!scratch.is(name));

  ASSERT(!extra.is(receiver));

  ASSERT(!extra.is(name));

  ASSERT(!extra.is(scratch));

  // Assert scratch and extra registers are valid, and extra2/3 are unused.

  ASSERT(!scratch.is(no_reg));

  ASSERT(extra2.is(no_reg));

  ASSERT(extra3.is(no_reg));

  Register offset = scratch;

  scratch = no_reg;

  Counters* counters = masm->isolate()->counters();

  __ IncrementCounter(counters->megamorphic_stub_cache_probes(), 1);

  // Check that the receiver isn't a smi.

  __ JumpIfSmi(receiver, &miss);

  // Get the map of the receiver and compute the hash.

  __ mov(offset, FieldOperand(name, Name::kHashFieldOffset));

  __ add(offset, FieldOperand(receiver, HeapObject::kMapOffset));

  __ xor_(offset, flags);

  // We mask out the last two bits because they are not part of the hash and

  // they are always 01 for maps.  Also in the two 'and' instructions below.

  __ and_(offset, (kPrimaryTableSize - 1) << kHeapObjectTagSize);

  // ProbeTable expects the offset to be pointer scaled, which it is, because

  // the heap object tag size is 2 and the pointer size log 2 is also 2.

  ASSERT(kHeapObjectTagSize == kPointerSizeLog2);

  // Probe the primary table.

  ProbeTable(isolate(), masm, flags, kPrimary, name, receiver, offset, extra);

  // Primary miss: Compute hash for secondary probe.

  __ mov(offset, FieldOperand(name, Name::kHashFieldOffset));

  __ add(offset, FieldOperand(receiver, HeapObject::kMapOffset));

  __ xor_(offset, flags);

  __ and_(offset, (kPrimaryTableSize - 1) << kHeapObjectTagSize);

  __ sub(offset, name);

  __ add(offset, Immediate(flags));

  __ and_(offset, (kSecondaryTableSize - 1) << kHeapObjectTagSize);

  // Probe the secondary table.

  ProbeTable(

      isolate(), masm, flags, kSecondary, name, receiver, offset, extra);

  // Cache miss: Fall-through and let caller handle the miss by

  // entering the runtime system.

  __ bind(&miss);

  __ IncrementCounter(counters->megamorphic_stub_cache_misses(), 1);

}

void StubCompiler::GenerateLoadGlobalFunctionPrototype(MacroAssembler* masm,

                                                       int index,

                                                       Register prototype) {

  __ LoadGlobalFunction(index, prototype);

  __ LoadGlobalFunctionInitialMap(prototype, prototype);

  // Load the prototype from the initial map.

  __ mov(prototype, FieldOperand(prototype, Map::kPrototypeOffset));

}

void StubCompiler::GenerateDirectLoadGlobalFunctionPrototype(

    MacroAssembler* masm,

    int index,

    Register prototype,

    Label* miss) {

  // Check we're still in the same context.

  __ cmp(Operand(esi, Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX)),

         masm->isolate()->global_object());

  __ j(not_equal, miss);

  // Get the global function with the given index.

  Handle<JSFunction> function(

      JSFunction::cast(masm->isolate()->native_context()->get(index)));

  // Load its initial map. The global functions all have initial maps.

  __ Set(prototype, Immediate(Handle<Map>(function->initial_map())));

  // Load the prototype from the initial map.

  __ mov(prototype, FieldOperand(prototype, Map::kPrototypeOffset));

}

void StubCompiler::GenerateLoadArrayLength(MacroAssembler* masm,

                                           Register receiver,

                                           Register scratch,

                                           Label* miss_label) {

  // Check that the receiver isn't a smi.

  __ JumpIfSmi(receiver, miss_label);

  // Check that the object is a JS array.

  __ CmpObjectType(receiver, JS_ARRAY_TYPE, scratch);

  __ j(not_equal, miss_label);

  // Load length directly from the JS array.

  __ mov(eax, FieldOperand(receiver, JSArray::kLengthOffset));

  __ ret(0);

}

// Generate code to check if an object is a string.  If the object is

// a string, the map's instance type is left in the scratch register.

static void GenerateStringCheck(MacroAssembler* masm,

                                Register receiver,

                                Register scratch,

                                Label* smi,

                                Label* non_string_object) {

  // Check that the object isn't a smi.

  __ JumpIfSmi(receiver, smi);

  // Check that the object is a string.

  __ mov(scratch, FieldOperand(receiver, HeapObject::kMapOffset));

  __ movzx_b(scratch, FieldOperand(scratch, Map::kInstanceTypeOffset));

  STATIC_ASSERT(kNotStringTag != 0);

  __ test(scratch, Immediate(kNotStringTag));

  __ j(not_zero, non_string_object);

}

void StubCompiler::GenerateLoadStringLength(MacroAssembler* masm,

                                            Register receiver,

                                            Register scratch1,

                                            Register scratch2,

                                            Label* miss) {

  Label check_wrapper;

  // Check if the object is a string leaving the instance type in the

  // scratch register.

  GenerateStringCheck(masm, receiver, scratch1, miss, &check_wrapper);

  // Load length from the string and convert to a smi.

  __ mov(eax, FieldOperand(receiver, String::kLengthOffset));

  __ ret(0);

  // Check if the object is a JSValue wrapper.

  __ bind(&check_wrapper);

  __ cmp(scratch1, JS_VALUE_TYPE);

  __ j(not_equal, miss);

  // Check if the wrapped value is a string and load the length

  // directly if it is.

  __ mov(scratch2, FieldOperand(receiver, JSValue::kValueOffset));

  GenerateStringCheck(masm, scratch2, scratch1, miss, miss);

  __ mov(eax, FieldOperand(scratch2, String::kLengthOffset));

  __ ret(0);

}

void StubCompiler::GenerateLoadFunctionPrototype(MacroAssembler* masm,

                                                 Register receiver,

                                                 Register scratch1,

                                                 Register scratch2,

                                                 Label* miss_label) {

  __ TryGetFunctionPrototype(receiver, scratch1, scratch2, miss_label);

  __ mov(eax, scratch1);

  __ ret(0);

}

void StubCompiler::GenerateFastPropertyLoad(MacroAssembler* masm,

                                            Register dst,

                                            Register src,

                                            bool inobject,

                                            int index,

                                            Representation representation) {

  ASSERT(!FLAG_track_double_fields || !representation.IsDouble());

  int offset = index * kPointerSize;

  if (!inobject) {

    // Calculate the offset into the properties array.

    offset = offset + FixedArray::kHeaderSize;

    __ mov(dst, FieldOperand(src, JSObject::kPropertiesOffset));

    src = dst;

  }

  __ mov(dst, FieldOperand(src, offset));

}

static void PushInterceptorArguments(MacroAssembler* masm,

                                     Register receiver,

                                     Register holder,

                                     Register name,

                                     Handle<JSObject> holder_obj) {

  STATIC_ASSERT(StubCache::kInterceptorArgsNameIndex == 0);

  STATIC_ASSERT(StubCache::kInterceptorArgsInfoIndex == 1);

  STATIC_ASSERT(StubCache::kInterceptorArgsThisIndex == 2);

  STATIC_ASSERT(StubCache::kInterceptorArgsHolderIndex == 3);

  STATIC_ASSERT(StubCache::kInterceptorArgsLength == 4);

  __ push(name);

  Handle<InterceptorInfo> interceptor(holder_obj->GetNamedInterceptor());

  ASSERT(!masm->isolate()->heap()->InNewSpace(*interceptor));

  Register scratch = name;

  __ mov(scratch, Immediate(interceptor));

  __ push(scratch);

  __ push(receiver);

  __ push(holder);

}

static void CompileCallLoadPropertyWithInterceptor(

    MacroAssembler* masm,

    Register receiver,

    Register holder,

    Register name,

    Handle<JSObject> holder_obj) {

  PushInterceptorArguments(masm, receiver, holder, name, holder_obj);

  __ CallExternalReference(

      ExternalReference(IC_Utility(IC::kLoadPropertyWithInterceptorOnly),

                        masm->isolate()),

      StubCache::kInterceptorArgsLength);

}

// Number of pointers to be reserved on stack for fast API call.

static const int kFastApiCallArguments = FunctionCallbackArguments::kArgsLength;

// Reserves space for the extra arguments to API function in the

// caller's frame.

//

// These arguments are set by CheckPrototypes and GenerateFastApiCall.

static void ReserveSpaceForFastApiCall(MacroAssembler* masm, Register scratch) {

  // ----------- S t a t e -------------

  //  -- esp[0] : return address

  //  -- esp[4] : last argument in the internal frame of the caller

  // -----------------------------------

  __ pop(scratch);

  for (int i = 0; i < kFastApiCallArguments; i++) {

    __ push(Immediate(Smi::FromInt(0)));

  }

  __ push(scratch);

}

// Undoes the effects of ReserveSpaceForFastApiCall.

static void FreeSpaceForFastApiCall(MacroAssembler* masm, Register scratch) {

  // ----------- S t a t e -------------

  //  -- esp[0]  : return address.

  //  -- esp[4]  : last fast api call extra argument.

  //  -- ...

  //  -- esp[kFastApiCallArguments * 4] : first fast api call extra argument.

  //  -- esp[kFastApiCallArguments * 4 + 4] : last argument in the internal

  //                                          frame.

  // -----------------------------------

  __ pop(scratch);

  __ add(esp, Immediate(kPointerSize * kFastApiCallArguments));

  __ push(scratch);

}

// Generates call to API function.

static void GenerateFastApiCall(MacroAssembler* masm,

                                const CallOptimization& optimization,

                                int argc,

                                bool restore_context) {

  // ----------- S t a t e -------------

  //  -- esp[0]              : return address

  //  -- esp[4] - esp[28]    : FunctionCallbackInfo, incl.

  //                         :  object passing the type check

  //                            (set by CheckPrototypes)

  //  -- esp[32]             : last argument

  //  -- ...

  //  -- esp[(argc + 7) * 4] : first argument

  //  -- esp[(argc + 8) * 4] : receiver

  // -----------------------------------

  typedef FunctionCallbackArguments FCA;

  // Save calling context.

  __ mov(Operand(esp, (1 + FCA::kContextSaveIndex) * kPointerSize), esi);

  // Get the function and setup the context.

  Handle<JSFunction> function = optimization.constant_function();

  __ LoadHeapObject(edi, function);

  __ mov(esi, FieldOperand(edi, JSFunction::kContextOffset));

  // Construct the FunctionCallbackInfo.

  __ mov(Operand(esp, (1 + FCA::kCalleeIndex) * kPointerSize), edi);

  Handle<CallHandlerInfo> api_call_info = optimization.api_call_info();

  Handle<Object> call_data(api_call_info->data(), masm->isolate());

  if (masm->isolate()->heap()->InNewSpace(*call_data)) {

    __ mov(ecx, api_call_info);

    __ mov(ebx, FieldOperand(ecx, CallHandlerInfo::kDataOffset));

    __ mov(Operand(esp, (1 + FCA::kDataIndex) * kPointerSize), ebx);

  } else {

    __ mov(Operand(esp, (1 + FCA::kDataIndex) * kPointerSize),

           Immediate(call_data));

  }

  __ mov(Operand(esp, (1 + FCA::kIsolateIndex) * kPointerSize),

         Immediate(reinterpret_cast<int>(masm->isolate())));

  __ mov(Operand(esp, (1 + FCA::kReturnValueOffset) * kPointerSize),

         masm->isolate()->factory()->undefined_value());

  __ mov(Operand(esp, (1 + FCA::kReturnValueDefaultValueIndex) * kPointerSize),

         masm->isolate()->factory()->undefined_value());

  // Prepare arguments.

  STATIC_ASSERT(kFastApiCallArguments == 7);

  __ lea(eax, Operand(esp, 1 * kPointerSize));

  // 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;

  // Function address is a foreign pointer outside V8's heap.

  Address function_address = v8::ToCData<Address>(api_call_info->callback());

  __ PrepareCallApiFunction(kApiArgc + kApiStackSpace);

  // FunctionCallbackInfo::implicit_args_.

  __ mov(ApiParameterOperand(2), eax);

  __ add(eax, Immediate((argc + kFastApiCallArguments - 1) * kPointerSize));

  // FunctionCallbackInfo::values_.

  __ mov(ApiParameterOperand(3), eax);

  // FunctionCallbackInfo::length_.

  __ Set(ApiParameterOperand(4), Immediate(argc));

  // FunctionCallbackInfo::is_construct_call_.

  __ Set(ApiParameterOperand(5), Immediate(0));

  // v8::InvocationCallback's argument.

  __ lea(eax, ApiParameterOperand(2));

  __ mov(ApiParameterOperand(0), eax);

  Address thunk_address = FUNCTION_ADDR(&InvokeFunctionCallback);

  Operand context_restore_operand(ebp,

                                  (2 + FCA::kContextSaveIndex) * kPointerSize);

  Operand return_value_operand(ebp,

                               (2 + FCA::kReturnValueOffset) * kPointerSize);

  __ CallApiFunctionAndReturn(function_address,

                              thunk_address,

                              ApiParameterOperand(1),

                              argc + kFastApiCallArguments + 1,

                              return_value_operand,

                              restore_context ?

                                  &context_restore_operand : NULL);

}

// Generate call to api function.

static void GenerateFastApiCall(MacroAssembler* masm,

                                const CallOptimization& optimization,

                                Register receiver,

                                Register scratch,

                                int argc,

                                Register* values) {

  ASSERT(optimization.is_simple_api_call());

  ASSERT(!receiver.is(scratch));

  const int stack_space = kFastApiCallArguments + argc + 1;

  const int kHolderIndex = FunctionCallbackArguments::kHolderIndex + 1;

  // Copy return value.

  __ mov(scratch, Operand(esp, 0));

  // Assign stack space for the call arguments.

  __ sub(esp, Immediate(stack_space * kPointerSize));

  // Move the return address on top of the stack.

  __ mov(Operand(esp, 0), scratch);

  // Write holder to stack frame.

  __ mov(Operand(esp, kHolderIndex * kPointerSize), receiver);

  // Write receiver to stack frame.

  int index = stack_space;

  __ mov(Operand(esp, index-- * kPointerSize), receiver);

  // Write the arguments to stack frame.

  for (int i = 0; i < argc; i++) {

    ASSERT(!receiver.is(values[i]));

    ASSERT(!scratch.is(values[i]));

    __ mov(Operand(esp, index-- * kPointerSize), values[i]);

  }

  GenerateFastApiCall(masm, optimization, argc, true);

}

class CallInterceptorCompiler BASE_EMBEDDED {

 public:

  CallInterceptorCompiler(StubCompiler* stub_compiler,

                          const ParameterCount& arguments,

                          Register name,

                          Code::ExtraICState extra_state)

      : stub_compiler_(stub_compiler),

        arguments_(arguments),

        name_(name),

        extra_state_(extra_state) {}

  void Compile(MacroAssembler* masm,

               Handle<JSObject> object,

               Handle<JSObject> holder,

               Handle<Name> name,

               LookupResult* lookup,

               Register receiver,

               Register scratch1,

               Register scratch2,

               Register scratch3,

               Label* miss) {

    ASSERT(holder->HasNamedInterceptor());

    ASSERT(!holder->GetNamedInterceptor()->getter()->IsUndefined());

    // Check that the receiver isn't a smi.

    __ JumpIfSmi(receiver, miss);

    CallOptimization optimization(lookup);

    if (optimization.is_constant_call()) {

      CompileCacheable(masm, object, receiver, scratch1, scratch2, scratch3,

                       holder, lookup, name, optimization, miss);

    } else {

      CompileRegular(masm, object, receiver, scratch1, scratch2, scratch3,

                     name, holder, miss);

    }

  }

 private:

  void CompileCacheable(MacroAssembler* masm,

                        Handle<JSObject> object,

                        Register receiver,

                        Register scratch1,

                        Register scratch2,

                        Register scratch3,

                        Handle<JSObject> interceptor_holder,

                        LookupResult* lookup,

                        Handle<Name> name,

                        const CallOptimization& optimization,

                        Label* miss_label) {

    ASSERT(optimization.is_constant_call());

    ASSERT(!lookup->holder()->IsGlobalObject());

    int depth1 = kInvalidProtoDepth;

    int depth2 = kInvalidProtoDepth;

    bool can_do_fast_api_call = false;

    if (optimization.is_simple_api_call() &&

        !lookup->holder()->IsGlobalObject()) {

      depth1 = optimization.GetPrototypeDepthOfExpectedType(

          object, interceptor_holder);

      if (depth1 == kInvalidProtoDepth) {

        depth2 = optimization.GetPrototypeDepthOfExpectedType(

            interceptor_holder, Handle<JSObject>(lookup->holder()));

      }

      can_do_fast_api_call =

          depth1 != kInvalidProtoDepth || depth2 != kInvalidProtoDepth;

    }

    Counters* counters = masm->isolate()->counters();

    __ IncrementCounter(counters->call_const_interceptor(), 1);

    if (can_do_fast_api_call) {

      __ IncrementCounter(counters->call_const_interceptor_fast_api(), 1);

      ReserveSpaceForFastApiCall(masm, scratch1);

    }

    // Check that the maps from receiver to interceptor's holder

    // haven't changed and thus we can invoke interceptor.

    Label miss_cleanup;

    Label* miss = can_do_fast_api_call ? &miss_cleanup : miss_label;

    Register holder =

        stub_compiler_->CheckPrototypes(object, receiver, interceptor_holder,

                                        scratch1, scratch2, scratch3,

                                        name, depth1, miss);

    // Invoke an interceptor and if it provides a value,

    // branch to |regular_invoke|.

    Label regular_invoke;

    LoadWithInterceptor(masm, receiver, holder, interceptor_holder,

                        &regular_invoke);

    // Interceptor returned nothing for this property.  Try to use cached

    // constant function.

    // Check that the maps from interceptor's holder to constant function's

    // holder haven't changed and thus we can use cached constant function.

    if (*interceptor_holder != lookup->holder()) {

      stub_compiler_->CheckPrototypes(interceptor_holder, receiver,

                                      Handle<JSObject>(lookup->holder()),

                                      scratch1, scratch2, scratch3,

                                      name, depth2, miss);

    } else {

      // CheckPrototypes has a side effect of fetching a 'holder'

      // for API (object which is instanceof for the signature).  It's

      // safe to omit it here, as if present, it should be fetched

      // by the previous CheckPrototypes.

      ASSERT(depth2 == kInvalidProtoDepth);

    }

    // Invoke function.

    if (can_do_fast_api_call) {

      GenerateFastApiCall(masm, optimization, arguments_.immediate(), false);

    } else {

      CallKind call_kind = CallICBase::Contextual::decode(extra_state_)

          ? CALL_AS_FUNCTION

          : CALL_AS_METHOD;

      Handle<JSFunction> function = optimization.constant_function();

      ParameterCount expected(function);

      __ InvokeFunction(function, expected, arguments_,

                        JUMP_FUNCTION, NullCallWrapper(), call_kind);

    }

    // Deferred code for fast API call case---clean preallocated space.

    if (can_do_fast_api_call) {

      __ bind(&miss_cleanup);

      FreeSpaceForFastApiCall(masm, scratch1);

      __ jmp(miss_label);

    }

    // Invoke a regular function.

    __ bind(&regular_invoke);

    if (can_do_fast_api_call) {

      FreeSpaceForFastApiCall(masm, scratch1);

    }

  }

  void CompileRegular(MacroAssembler* masm,

                      Handle<JSObject> object,

                      Register receiver,

                      Register scratch1,

                      Register scratch2,

                      Register scratch3,

                      Handle<Name> name,

                      Handle<JSObject> interceptor_holder,

                      Label* miss_label) {

    Register holder =

        stub_compiler_->CheckPrototypes(object, receiver, interceptor_holder,

                                        scratch1, scratch2, scratch3,

                                        name, miss_label);

    FrameScope scope(masm, StackFrame::INTERNAL);

    // Save the name_ register across the call.

    __ push(name_);

    PushInterceptorArguments(masm, receiver, holder, name_, interceptor_holder);

    __ CallExternalReference(

        ExternalReference(IC_Utility(IC::kLoadPropertyWithInterceptorForCall),

                          masm->isolate()),

        StubCache::kInterceptorArgsLength);

    // Restore the name_ register.

    __ pop(name_);

    // Leave the internal frame.

  }

  void LoadWithInterceptor(MacroAssembler* masm,

                           Register receiver,

                           Register holder,

                           Handle<JSObject> holder_obj,

                           Label* interceptor_succeeded) {

    {

      FrameScope scope(masm, StackFrame::INTERNAL);

      __ push(holder);  // Save the holder.

      __ push(name_);  // Save the name.

      CompileCallLoadPropertyWithInterceptor(masm,

                                             receiver,

                                             holder,

                                             name_,

                                             holder_obj);

      __ pop(name_);  // Restore the name.

      __ pop(receiver);  // Restore the holder.

      // Leave the internal frame.

    }

    __ cmp(eax, masm->isolate()->factory()->no_interceptor_result_sentinel());

    __ j(not_equal, interceptor_succeeded);

  }

  StubCompiler* stub_compiler_;

  const ParameterCount& arguments_;

  Register name_;

  Code::ExtraICState extra_state_;

};

void StoreStubCompiler::GenerateRestoreName(MacroAssembler* masm,

                                            Label* label,

                                            Handle<Name> name) {

  if (!label->is_unused()) {

    __ bind(label);

    __ mov(this->name(), Immediate(name));

  }

}

// Generate code to check that a global property cell is empty. Create

// the property cell at compilation time if no cell exists for the

// property.

static void GenerateCheckPropertyCell(MacroAssembler* masm,

                                      Handle<GlobalObject> global,

                                      Handle<Name> name,

                                      Register scratch,

                                      Label* miss) {

  Handle<PropertyCell> cell =

      GlobalObject::EnsurePropertyCell(global, name);

  ASSERT(cell->value()->IsTheHole());

  Handle<Oddball> the_hole = masm->isolate()->factory()->the_hole_value();

  if (Serializer::enabled()) {

    __ mov(scratch, Immediate(cell));

    __ cmp(FieldOperand(scratch, PropertyCell::kValueOffset),

           Immediate(the_hole));

  } else {

    __ cmp(Operand::ForCell(cell), Immediate(the_hole));

  }

  __ j(not_equal, miss);

}

void StoreStubCompiler::GenerateNegativeHolderLookup(

    MacroAssembler* masm,

    Handle<JSObject> holder,

    Register holder_reg,

    Handle<Name> name,

    Label* miss) {

  if (holder->IsJSGlobalObject()) {

    GenerateCheckPropertyCell(

        masm, Handle<GlobalObject>::cast(holder), name, scratch1(), miss);

  } else if (!holder->HasFastProperties() && !holder->IsJSGlobalProxy()) {

    GenerateDictionaryNegativeLookup(

        masm, miss, holder_reg, name, scratch1(), scratch2());

  }

}

// Receiver_reg is preserved on jumps to miss_label, but may be destroyed if

// store is successful.

void StoreStubCompiler::GenerateStoreTransition(MacroAssembler* masm,

                                                Handle<JSObject> object,

                                                LookupResult* lookup,

                                                Handle<Map> transition,

                                                Handle<Name> name,

                                                Register receiver_reg,

                                                Register storage_reg,

                                                Register value_reg,

                                                Register scratch1,

                                                Register scratch2,

                                                Register unused,

                                                Label* miss_label,

                                                Label* slow) {

  int descriptor = transition->LastAdded();

  DescriptorArray* descriptors = transition->instance_descriptors();

  PropertyDetails details = descriptors->GetDetails(descriptor);

  Representation representation = details.representation();

  ASSERT(!representation.IsNone());

  if (details.type() == CONSTANT) {

    Handle<Object> constant(descriptors->GetValue(descriptor), masm->isolate());

    __ CmpObject(value_reg, constant);

    __ j(not_equal, miss_label);

  } else if (FLAG_track_fields && representation.IsSmi()) {

      __ JumpIfNotSmi(value_reg, miss_label);

  } else if (FLAG_track_heap_object_fields && representation.IsHeapObject()) {

    __ JumpIfSmi(value_reg, miss_label);

  } else if (FLAG_track_double_fields && representation.IsDouble()) {

    Label do_store, heap_number;

    __ AllocateHeapNumber(storage_reg, scratch1, scratch2, slow);

    __ JumpIfNotSmi(value_reg, &heap_number);

    __ SmiUntag(value_reg);

    if (CpuFeatures::IsSupported(SSE2)) {

      CpuFeatureScope use_sse2(masm, SSE2);

      __ Cvtsi2sd(xmm0, value_reg);

    } else {

      __ push(value_reg);

      __ fild_s(Operand(esp, 0));

      __ pop(value_reg);

    }

    __ SmiTag(value_reg);

    __ jmp(&do_store);

    __ bind(&heap_number);

    __ CheckMap(value_reg, masm->isolate()->factory()->heap_number_map(),

                miss_label, DONT_DO_SMI_CHECK);

    if (CpuFeatures::IsSupported(SSE2)) {

      CpuFeatureScope use_sse2(masm, SSE2);

      __ movsd(xmm0, FieldOperand(value_reg, HeapNumber::kValueOffset));

    } else {

      __ fld_d(FieldOperand(value_reg, HeapNumber::kValueOffset));

    }

    __ bind(&do_store);

    if (CpuFeatures::IsSupported(SSE2)) {

      CpuFeatureScope use_sse2(masm, SSE2);

      __ movsd(FieldOperand(storage_reg, HeapNumber::kValueOffset), xmm0);

    } else {

      __ fstp_d(FieldOperand(storage_reg, HeapNumber::kValueOffset));

    }

  }

  // Stub never generated for non-global objects that require access

  // checks.

  ASSERT(object->IsJSGlobalProxy() || !object->IsAccessCheckNeeded());

  // Perform map transition for the receiver if necessary.

  if (details.type() == FIELD &&

      object->map()->unused_property_fields() == 0) {

    // The properties must be extended before we can store the value.

    // We jump to a runtime call that extends the properties array.

    __ pop(scratch1);  // Return address.

    __ push(receiver_reg);

    __ push(Immediate(transition));

    __ push(value_reg);

    __ push(scratch1);

    __ TailCallExternalReference(

        ExternalReference(IC_Utility(IC::kSharedStoreIC_ExtendStorage),

                          masm->isolate()),

        3,

        1);

    return;

  }

  // Update the map of the object.

  __ mov(scratch1, Immediate(transition));

  __ mov(FieldOperand(receiver_reg, HeapObject::kMapOffset), scratch1);

  // Update the write barrier for the map field.

  __ RecordWriteField(receiver_reg,

                      HeapObject::kMapOffset,

                      scratch1,

                      scratch2,

                      kDontSaveFPRegs,

                      OMIT_REMEMBERED_SET,

                      OMIT_SMI_CHECK);

  if (details.type() == CONSTANT) {

    ASSERT(value_reg.is(eax));

    __ ret(0);

    return;

  }

  int index = transition->instance_descriptors()->GetFieldIndex(

      transition->LastAdded());

  // Adjust for the number of properties stored in the object. Even in the

  // face of a transition we can use the old map here because the size of the

  // object and the number of in-object properties is not going to change.

  index -= object->map()->inobject_properties();

  SmiCheck smi_check = representation.IsTagged()

      ? INLINE_SMI_CHECK : OMIT_SMI_CHECK;

  // TODO(verwaest): Share this code as a code stub.

  if (index < 0) {

    // Set the property straight into the object.

    int offset = object->map()->instance_size() + (index * kPointerSize);

    if (FLAG_track_double_fields && representation.IsDouble()) {

      __ mov(FieldOperand(receiver_reg, offset), storage_reg);

    } else {

      __ mov(FieldOperand(receiver_reg, offset), value_reg);

    }

    if (!FLAG_track_fields || !representation.IsSmi()) {

      // Update the write barrier for the array address.

      if (!FLAG_track_double_fields || !representation.IsDouble()) {

        __ mov(storage_reg, value_reg);

      }

      __ RecordWriteField(receiver_reg,

                          offset,

                          storage_reg,

                          scratch1,

                          kDontSaveFPRegs,

                          EMIT_REMEMBERED_SET,

                          smi_check);

    }

  } else {

    // Write to the properties array.

    int offset = index * kPointerSize + FixedArray::kHeaderSize;

    // Get the properties array (optimistically).

    __ mov(scratch1, FieldOperand(receiver_reg, JSObject::kPropertiesOffset));

    if (FLAG_track_double_fields && representation.IsDouble()) {

      __ mov(FieldOperand(scratch1, offset), storage_reg);

    } else {

      __ mov(FieldOperand(scratch1, offset), value_reg);

    }

    if (!FLAG_track_fields || !representation.IsSmi()) {

      // Update the write barrier for the array address.

      if (!FLAG_track_double_fields || !representation.IsDouble()) {

        __ mov(storage_reg, value_reg);

      }

      __ RecordWriteField(scratch1,

                          offset,

                          storage_reg,

                          receiver_reg,

                          kDontSaveFPRegs,

                          EMIT_REMEMBERED_SET,

                          smi_check);

    }

  }

  // Return the value (register eax).

  ASSERT(value_reg.is(eax));

  __ ret(0);

}

// Both name_reg and receiver_reg are preserved on jumps to miss_label,

// but may be destroyed if store is successful.

void StoreStubCompiler::GenerateStoreField(MacroAssembler* masm,

                                           Handle<JSObject> object,

                                           LookupResult* lookup,

                                           Register receiver_reg,

                                           Register name_reg,

                                           Register value_reg,

                                           Register scratch1,

                                           Register scratch2,

                                           Label* miss_label) {

  // Stub never generated for non-global objects that require access

  // checks.

  ASSERT(object->IsJSGlobalProxy() || !object->IsAccessCheckNeeded());

  int index = lookup->GetFieldIndex().field_index();

  // Adjust for the number of properties stored in the object. Even in the

  // face of a transition we can use the old map here because the size of the

  // object and the number of in-object properties is not going to change.

  index -= object->map()->inobject_properties();

  Representation representation = lookup->representation();

  ASSERT(!representation.IsNone());

  if (FLAG_track_fields && representation.IsSmi()) {

    __ JumpIfNotSmi(value_reg, miss_label);

  } else if (FLAG_track_heap_object_fields && representation.IsHeapObject()) {

    __ JumpIfSmi(value_reg, miss_label);

  } else if (FLAG_track_double_fields && representation.IsDouble()) {

    // Load the double storage.

    if (index < 0) {

      int offset = object->map()->instance_size() + (index * kPointerSize);

      __ mov(scratch1, FieldOperand(receiver_reg, offset));

    } else {

      __ mov(scratch1, FieldOperand(receiver_reg, JSObject::kPropertiesOffset));

      int offset = index * kPointerSize + FixedArray::kHeaderSize;

      __ mov(scratch1, FieldOperand(scratch1, offset));

    }

    // Store the value into the storage.

    Label do_store, heap_number;

    __ JumpIfNotSmi(value_reg, &heap_number);

    __ SmiUntag(value_reg);

    if (CpuFeatures::IsSupported(SSE2)) {

      CpuFeatureScope use_sse2(masm, SSE2);

      __ Cvtsi2sd(xmm0, value_reg);

    } else {

      __ push(value_reg);

      __ fild_s(Operand(esp, 0));

      __ pop(value_reg);

    }

    __ SmiTag(value_reg);

    __ jmp(&do_store);

    __ bind(&heap_number);

    __ CheckMap(value_reg, masm->isolate()->factory()->heap_number_map(),

                miss_label, DONT_DO_SMI_CHECK);

    if (CpuFeatures::IsSupported(SSE2)) {

      CpuFeatureScope use_sse2(masm, SSE2);

      __ movsd(xmm0, FieldOperand(value_reg, HeapNumber::kValueOffset));

    } else {

      __ fld_d(FieldOperand(value_reg, HeapNumber::kValueOffset));

    }

    __ bind(&do_store);

    if (CpuFeatures::IsSupported(SSE2)) {

      CpuFeatureScope use_sse2(masm, SSE2);

      __ movsd(FieldOperand(scratch1, HeapNumber::kValueOffset), xmm0);

    } else {

      __ fstp_d(FieldOperand(scratch1, HeapNumber::kValueOffset));

    }

    // Return the value (register eax).

    ASSERT(value_reg.is(eax));

    __ ret(0);

    return;

  }

  ASSERT(!FLAG_track_double_fields || !representation.IsDouble());

  // TODO(verwaest): Share this code as a code stub.

  SmiCheck smi_check = representation.IsTagged()

      ? INLINE_SMI_CHECK : OMIT_SMI_CHECK;

  if (index < 0) {

    // Set the property straight into the object.

    int offset = object->map()->instance_size() + (index * kPointerSize);

    __ mov(FieldOperand(receiver_reg, offset), value_reg);

    if (!FLAG_track_fields || !representation.IsSmi()) {

      // Update the write barrier for the array address.

      // Pass the value being stored in the now unused name_reg.

      __ mov(name_reg, value_reg);

      __ RecordWriteField(receiver_reg,

                          offset,

                          name_reg,

                          scratch1,

                          kDontSaveFPRegs,

                          EMIT_REMEMBERED_SET,

                          smi_check);

    }

  } else {

    // Write to the properties array.

    int offset = index * kPointerSize + FixedArray::kHeaderSize;

    // Get the properties array (optimistically).

    __ mov(scratch1, FieldOperand(receiver_reg, JSObject::kPropertiesOffset));

    __ mov(FieldOperand(scratch1, offset), value_reg);

    if (!FLAG_track_fields || !representation.IsSmi()) {

      // Update the write barrier for the array address.

      // Pass the value being stored in the now unused name_reg.

      __ mov(name_reg, value_reg);

      __ RecordWriteField(scratch1,

                          offset,

                          name_reg,

                          receiver_reg,

                          kDontSaveFPRegs,

                          EMIT_REMEMBERED_SET,

                          smi_check);

    }

  }

  // Return the value (register eax).

  ASSERT(value_reg.is(eax));

  __ ret(0);

}

// Calls GenerateCheckPropertyCell for each global object in the prototype chain

// from object to (but not including) holder.

static void GenerateCheckPropertyCells(MacroAssembler* masm,

                                       Handle<JSObject> object,

                                       Handle<JSObject> holder,

                                       Handle<Name> name,

                                       Register scratch,

                                       Label* miss) {

  Handle<JSObject> current = object;

  while (!current.is_identical_to(holder)) {

    if (current->IsGlobalObject()) {

      GenerateCheckPropertyCell(masm,

                                Handle<GlobalObject>::cast(current),

                                name,

                                scratch,

                                miss);

    }

    current = Handle<JSObject>(JSObject::cast(current->GetPrototype()));

  }

}

void StubCompiler::GenerateTailCall(MacroAssembler* masm, Handle<Code> code) {

  __ jmp(code, RelocInfo::CODE_TARGET);

}

#undef __

#define __ ACCESS_MASM(masm())

Register StubCompiler::CheckPrototypes(Handle<JSObject> object,

                                       Register object_reg,

                                       Handle<JSObject> holder,

                                       Register holder_reg,

                                       Register scratch1,

                                       Register scratch2,

                                       Handle<Name> name,

                                       int save_at_depth,

                                       Label* miss,

                                       PrototypeCheckType check) {

  const int kHolderIndex = FunctionCallbackArguments::kHolderIndex + 1;

  // Make sure that the type feedback oracle harvests the receiver map.

  // TODO(svenpanne) Remove this hack when all ICs are reworked.

  __ mov(scratch1, Handle<Map>(object->map()));

  Handle<JSObject> first = object;

  // Make sure there's no overlap between holder and object registers.

  ASSERT(!scratch1.is(object_reg) && !scratch1.is(holder_reg));

  ASSERT(!scratch2.is(object_reg) && !scratch2.is(holder_reg)

         && !scratch2.is(scratch1));

  // Keep track of the current object in register reg.

  Register reg = object_reg;

  Handle<JSObject> current = object;

  int depth = 0;

  if (save_at_depth == depth) {

    __ mov(Operand(esp, kHolderIndex * kPointerSize), reg);

  }

  // Traverse the prototype chain and check the maps in the prototype chain for

  // fast and global objects or do negative lookup for normal objects.

  while (!current.is_identical_to(holder)) {

    ++depth;

    // Only global objects and objects that do not require access

    // checks are allowed in stubs.

    ASSERT(current->IsJSGlobalProxy() || !current->IsAccessCheckNeeded());

    Handle<JSObject> prototype(JSObject::cast(current->GetPrototype()));

    if (!current->HasFastProperties() &&

        !current->IsJSGlobalObject() &&

        !current->IsJSGlobalProxy()) {

      if (!name->IsUniqueName()) {

        ASSERT(name->IsString());

        name = factory()->InternalizeString(Handle<String>::cast(name));

      }

      ASSERT(current->property_dictionary()->FindEntry(*name) ==

             NameDictionary::kNotFound);

      GenerateDictionaryNegativeLookup(masm(), miss, reg, name,

                                       scratch1, scratch2);

      __ mov(scratch1, FieldOperand(reg, HeapObject::kMapOffset));

      reg = holder_reg;  // From now on the object will be in holder_reg.

      __ mov(reg, FieldOperand(scratch1, Map::kPrototypeOffset));

    } else {

      bool in_new_space = heap()->InNewSpace(*prototype);

      Handle<Map> current_map(current->map());

      if (!current.is_identical_to(first) || check == CHECK_ALL_MAPS) {

        __ CheckMap(reg, current_map, miss, DONT_DO_SMI_CHECK);

      }

      // Check access rights to the global object.  This has to happen after

      // the map check so that we know that the object is actually a global

      // object.

      if (current->IsJSGlobalProxy()) {

        __ CheckAccessGlobalProxy(reg, scratch1, scratch2, miss);

      }

      if (in_new_space) {

        // Save the map in scratch1 for later.

        __ mov(scratch1, FieldOperand(reg, HeapObject::kMapOffset));

      }

      reg = holder_reg;  // From now on the object will be in holder_reg.

      if (in_new_space) {

        // The prototype is in new space; we cannot store a reference to it

        // in the code.  Load it from the map.

        __ mov(reg, FieldOperand(scratch1, Map::kPrototypeOffset));

      } else {

        // The prototype is in old space; load it directly.

        __ mov(reg, prototype);

      }

    }

    if (save_at_depth == depth) {

      __ mov(Operand(esp, kHolderIndex * kPointerSize), reg);

    }

    // Go to the next object in the prototype chain.

    current = prototype;

  }

  ASSERT(current.is_identical_to(holder));

  // Log the check depth.

  LOG(isolate(), IntEvent("check-maps-depth", depth + 1));

  if (!holder.is_identical_to(first) || check == CHECK_ALL_MAPS) {

    // Check the holder map.

    __ CheckMap(reg, Handle<Map>(holder->map()), miss, DONT_DO_SMI_CHECK);

  }

  // Perform security check for access to the global object.

  ASSERT(holder->IsJSGlobalProxy() || !holder->IsAccessCheckNeeded());

  if (holder->IsJSGlobalProxy()) {

    __ CheckAccessGlobalProxy(reg, scratch1, scratch2, miss);

  }

  // If we've skipped any global objects, it's not enough to verify that

  // their maps haven't changed.  We also need to check that the property

  // cell for the property is still empty.

  GenerateCheckPropertyCells(masm(), object, holder, name, scratch1, miss);

  // Return the register containing the holder.

  return reg;

}

void LoadStubCompiler::HandlerFrontendFooter(Handle<Name> name,

                                             Label* success,

                                             Label* miss) {

  if (!miss->is_unused()) {

    __ jmp(success);

    __ bind(miss);

    TailCallBuiltin(masm(), MissBuiltin(kind()));

  }

}

void StoreStubCompiler::HandlerFrontendFooter(Handle<Name> name,

                                              Label* success,

                                              Label* miss) {

  if (!miss->is_unused()) {

    __ jmp(success);

    GenerateRestoreName(masm(), miss, name);

    TailCallBuiltin(masm(), MissBuiltin(kind()));

  }

}

Register LoadStubCompiler::CallbackHandlerFrontend(

    Handle<JSObject> object,

    Register object_reg,

    Handle<JSObject> holder,

    Handle<Name> name,

    Label* success,

    Handle<Object> callback) {

  Label miss;

  Register reg = HandlerFrontendHeader(object, object_reg, holder, name, &miss);

  if (!holder->HasFastProperties() && !holder->IsJSGlobalObject()) {

    ASSERT(!reg.is(scratch2()));

    ASSERT(!reg.is(scratch3()));

    Register dictionary = scratch1();

    bool must_preserve_dictionary_reg = reg.is(dictionary);

    // Load the properties dictionary.

    if (must_preserve_dictionary_reg) {

      __ push(dictionary);

    }

    __ mov(dictionary, FieldOperand(reg, JSObject::kPropertiesOffset));

    // Probe the dictionary.

    Label probe_done, pop_and_miss;

    NameDictionaryLookupStub::GeneratePositiveLookup(masm(),

                                                     &pop_and_miss,

                                                     &probe_done,

                                                     dictionary,

                                                     this->name(),

                                                     scratch2(),

                                                     scratch3());

    __ bind(&pop_and_miss);

    if (must_preserve_dictionary_reg) {

      __ pop(dictionary);

    }

    __ jmp(&miss);

    __ bind(&probe_done);

    // If probing finds an entry in the dictionary, scratch2 contains the

    // index into the dictionary. Check that the value is the callback.

    Register index = scratch2();

    const int kElementsStartOffset =

        NameDictionary::kHeaderSize +

        NameDictionary::kElementsStartIndex * kPointerSize;

    const int kValueOffset = kElementsStartOffset + kPointerSize;

    __ mov(scratch3(),

           Operand(dictionary, index, times_4, kValueOffset - kHeapObjectTag));

    if (must_preserve_dictionary_reg) {

      __ pop(dictionary);

    }

    __ cmp(scratch3(), callback);

    __ j(not_equal, &miss);

  }

  HandlerFrontendFooter(name, success, &miss);

  return reg;

}

void LoadStubCompiler::NonexistentHandlerFrontend(

    Handle<JSObject> object,

    Handle<JSObject> last,

    Handle<Name> name,

    Label* success,

    Handle<GlobalObject> global) {

  Label miss;

  HandlerFrontendHeader(object, receiver(), last, name, &miss);

  // If the last object in the prototype chain is a global object,

  // check that the global property cell is empty.

  if (!global.is_null()) {

    GenerateCheckPropertyCell(masm(), global, name, scratch2(), &miss);

  }

  HandlerFrontendFooter(name, success, &miss);

}

void LoadStubCompiler::GenerateLoadField(Register reg,

                                         Handle<JSObject> holder,

                                         PropertyIndex field,

                                         Representation representation) {

  if (!reg.is(receiver())) __ mov(receiver(), reg);

  if (kind() == Code::LOAD_IC) {

    LoadFieldStub stub(field.is_inobject(holder),

                       field.translate(holder),

                       representation);

    GenerateTailCall(masm(), stub.GetCode(isolate()));

  } else {

    KeyedLoadFieldStub stub(field.is_inobject(holder),

                            field.translate(holder),

                            representation);

    GenerateTailCall(masm(), stub.GetCode(isolate()));

  }

}

void LoadStubCompiler::GenerateLoadCallback(

    const CallOptimization& call_optimization) {

  GenerateFastApiCall(

      masm(), call_optimization, receiver(), scratch3(), 0, NULL);

}

void LoadStubCompiler::GenerateLoadCallback(

    Register reg,

    Handle<ExecutableAccessorInfo> callback) {

  // Insert additional parameters into the stack frame above return address.

  ASSERT(!scratch3().is(reg));

  __ pop(scratch3());  // Get return address to place it below.

  STATIC_ASSERT(PropertyCallbackArguments::kHolderIndex == 0);

  STATIC_ASSERT(PropertyCallbackArguments::kIsolateIndex == 1);

  STATIC_ASSERT(PropertyCallbackArguments::kReturnValueDefaultValueIndex == 2);

  STATIC_ASSERT(PropertyCallbackArguments::kReturnValueOffset == 3);

  STATIC_ASSERT(PropertyCallbackArguments::kDataIndex == 4);

  STATIC_ASSERT(PropertyCallbackArguments::kThisIndex == 5);

  __ push(receiver());  // receiver

  // Push data from ExecutableAccessorInfo.

  if (isolate()->heap()->InNewSpace(callback->data())) {

    ASSERT(!scratch2().is(reg));

    __ mov(scratch2(), Immediate(callback));

    __ push(FieldOperand(scratch2(), ExecutableAccessorInfo::kDataOffset));

  } else {

    __ push(Immediate(Handle<Object>(callback->data(), isolate())));

  }

  __ push(Immediate(isolate()->factory()->undefined_value()));  // ReturnValue

  // ReturnValue default value

  __ push(Immediate(isolate()->factory()->undefined_value()));

  __ push(Immediate(reinterpret_cast<int>(isolate())));

  __ push(reg);  // holder

  // Save a pointer to where we pushed the arguments. This will be

  // passed as the const PropertyAccessorInfo& to the C++ callback.

  __ push(esp);

  __ push(name());  // name

  __ mov(ebx, esp);  // esp points to reference to name (handler).

  __ push(scratch3());  // Restore return 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;

  Address getter_address = v8::ToCData<Address>(callback->getter());

  __ PrepareCallApiFunction(kApiArgc);

  __ mov(ApiParameterOperand(0), ebx);  // name.

  __ add(ebx, Immediate(kPointerSize));

  __ mov(ApiParameterOperand(1), ebx);  // arguments pointer.

  // Emitting a stub call may try to allocate (if the code is not

  // already generated).  Do not allow the assembler to perform a

  // garbage collection but instead return the allocation failure

  // object.

  Address thunk_address = FUNCTION_ADDR(&InvokeAccessorGetterCallback);

  __ CallApiFunctionAndReturn(getter_address,

                              thunk_address,

                              ApiParameterOperand(2),

                              kStackSpace,

                              Operand(ebp, 7 * kPointerSize),

                              NULL);