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_MIPS

#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 receiver,

                       Register name,

                       // Number of the cache entry, not scaled.

                       Register offset,

                       Register scratch,

                       Register scratch2,

                       Register offset_scratch) {

  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));

  uint32_t key_off_addr = reinterpret_cast<uint32_t>(key_offset.address());

  uint32_t value_off_addr = reinterpret_cast<uint32_t>(value_offset.address());

  uint32_t map_off_addr = reinterpret_cast<uint32_t>(map_offset.address());

  // Check the relative positions of the address fields.

  ASSERT(value_off_addr > key_off_addr);

  ASSERT((value_off_addr - key_off_addr) % 4 == 0);

  ASSERT((value_off_addr - key_off_addr) < (256 * 4));

  ASSERT(map_off_addr > key_off_addr);

  ASSERT((map_off_addr - key_off_addr) % 4 == 0);

  ASSERT((map_off_addr - key_off_addr) < (256 * 4));

  Label miss;

  Register base_addr = scratch;

  scratch = no_reg;

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

  __ sll(offset_scratch, offset, 1);

  __ Addu(offset_scratch, offset_scratch, offset);

  // Calculate the base address of the entry.

  __ li(base_addr, Operand(key_offset));

  __ sll(at, offset_scratch, kPointerSizeLog2);

  __ Addu(base_addr, base_addr, at);

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

  __ lw(at, MemOperand(base_addr, 0));

  __ Branch(&miss, ne, name, Operand(at));

  // Check the map matches.

  __ lw(at, MemOperand(base_addr, map_off_addr - key_off_addr));

  __ lw(scratch2, FieldMemOperand(receiver, HeapObject::kMapOffset));

  __ Branch(&miss, ne, at, Operand(scratch2));

  // Get the code entry from the cache.

  Register code = scratch2;

  scratch2 = no_reg;

  __ lw(code, MemOperand(base_addr, value_off_addr - key_off_addr));

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

  Register flags_reg = base_addr;

  base_addr = no_reg;

  __ lw(flags_reg, FieldMemOperand(code, Code::kFlagsOffset));

  __ And(flags_reg, flags_reg, Operand(~Code::kFlagsNotUsedInLookup));

  __ Branch(&miss, ne, flags_reg, Operand(flags));

#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.

  __ Addu(at, code, Operand(Code::kHeaderSize - kHeapObjectTag));

  __ Jump(at);

  // Miss: fall through.

  __ bind(&miss);

}

// 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 scratch0,

                                             Register scratch1) {

  ASSERT(name->IsUniqueName());

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

  __ IncrementCounter(counters->negative_lookups(), 1, scratch0, scratch1);

  __ IncrementCounter(counters->negative_lookups_miss(), 1, scratch0, scratch1);

  Label done;

  const int kInterceptorOrAccessCheckNeededMask =

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

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

  Register map = scratch1;

  __ lw(map, FieldMemOperand(receiver, HeapObject::kMapOffset));

  __ lbu(scratch0, FieldMemOperand(map, Map::kBitFieldOffset));

  __ And(scratch0, scratch0, Operand(kInterceptorOrAccessCheckNeededMask));

  __ Branch(miss_label, ne, scratch0, Operand(zero_reg));

  // Check that receiver is a JSObject.

  __ lbu(scratch0, FieldMemOperand(map, Map::kInstanceTypeOffset));

  __ Branch(miss_label, lt, scratch0, Operand(FIRST_SPEC_OBJECT_TYPE));

  // Load properties array.

  Register properties = scratch0;

  __ lw(properties, FieldMemOperand(receiver, JSObject::kPropertiesOffset));

  // Check that the properties array is a dictionary.

  __ lw(map, FieldMemOperand(properties, HeapObject::kMapOffset));

  Register tmp = properties;

  __ LoadRoot(tmp, Heap::kHashTableMapRootIndex);

  __ Branch(miss_label, ne, map, Operand(tmp));

  // Restore the temporarily used register.

  __ lw(properties, FieldMemOperand(receiver, JSObject::kPropertiesOffset));

  NameDictionaryLookupStub::GenerateNegativeLookup(masm,

                                                   miss_label,

                                                   &done,

                                                   receiver,

                                                   properties,

                                                   name,

                                                   scratch1);

  __ bind(&done);

  __ DecrementCounter(counters->negative_lookups_miss(), 1, scratch0, scratch1);

}

void StubCache::GenerateProbe(MacroAssembler* masm,

                              Code::Flags flags,

                              Register receiver,

                              Register name,

                              Register scratch,

                              Register extra,

                              Register extra2,

                              Register extra3) {

  Isolate* isolate = masm->isolate();

  Label miss;

  // Make sure that code is valid. The multiplying code relies on the

  // entry size being 12.

  ASSERT(sizeof(Entry) == 12);

  // Make sure the flags does not name a specific type.

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

  // Make sure 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(!extra2.is(receiver));

  ASSERT(!extra2.is(name));

  ASSERT(!extra2.is(scratch));

  ASSERT(!extra2.is(extra));

  // Check register validity.

  ASSERT(!scratch.is(no_reg));

  ASSERT(!extra.is(no_reg));

  ASSERT(!extra2.is(no_reg));

  ASSERT(!extra3.is(no_reg));

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

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

                      extra2, extra3);

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

  __ JumpIfSmi(receiver, &miss);

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

  __ lw(scratch, FieldMemOperand(name, Name::kHashFieldOffset));

  __ lw(at, FieldMemOperand(receiver, HeapObject::kMapOffset));

  __ Addu(scratch, scratch, at);

  uint32_t mask = kPrimaryTableSize - 1;

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

  // they are always 01 for maps.

  __ srl(scratch, scratch, kHeapObjectTagSize);

  __ Xor(scratch, scratch, Operand((flags >> kHeapObjectTagSize) & mask));

  __ And(scratch, scratch, Operand(mask));

  // Probe the primary table.

  ProbeTable(isolate,

             masm,

             flags,

             kPrimary,

             receiver,

             name,

             scratch,

             extra,

             extra2,

             extra3);

  // Primary miss: Compute hash for secondary probe.

  __ srl(at, name, kHeapObjectTagSize);

  __ Subu(scratch, scratch, at);

  uint32_t mask2 = kSecondaryTableSize - 1;

  __ Addu(scratch, scratch, Operand((flags >> kHeapObjectTagSize) & mask2));

  __ And(scratch, scratch, Operand(mask2));

  // Probe the secondary table.

  ProbeTable(isolate,

             masm,

             flags,

             kSecondary,

             receiver,

             name,

             scratch,

             extra,

             extra2,

             extra3);

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

  // entering the runtime system.

  __ bind(&miss);

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

                      extra2, extra3);

}

void StubCompiler::GenerateLoadGlobalFunctionPrototype(MacroAssembler* masm,

                                                       int index,

                                                       Register prototype) {

  // Load the global or builtins object from the current context.

  __ lw(prototype,

        MemOperand(cp, Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX)));

  // Load the native context from the global or builtins object.

  __ lw(prototype,

         FieldMemOperand(prototype, GlobalObject::kNativeContextOffset));

  // Load the function from the native context.

  __ lw(prototype, MemOperand(prototype, Context::SlotOffset(index)));

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

  __ lw(prototype,

         FieldMemOperand(prototype, JSFunction::kPrototypeOrInitialMapOffset));

  // Load the prototype from the initial map.

  __ lw(prototype, FieldMemOperand(prototype, Map::kPrototypeOffset));

}

void StubCompiler::GenerateDirectLoadGlobalFunctionPrototype(

    MacroAssembler* masm,

    int index,

    Register prototype,

    Label* miss) {

  Isolate* isolate = masm->isolate();

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

  __ lw(prototype,

        MemOperand(cp, Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX)));

  ASSERT(!prototype.is(at));

  __ li(at, isolate->global_object());

  __ Branch(miss, ne, prototype, Operand(at));

  // Get the global function with the given index.

  Handle<JSFunction> function(

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

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

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

  // Load the prototype from the initial map.

  __ lw(prototype, FieldMemOperand(prototype, Map::kPrototypeOffset));

}

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;

    __ lw(dst, FieldMemOperand(src, JSObject::kPropertiesOffset));

    src = dst;

  }

  __ lw(dst, FieldMemOperand(src, offset));

}

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.

  __ GetObjectType(receiver, scratch, scratch);

  __ Branch(miss_label, ne, scratch, Operand(JS_ARRAY_TYPE));

  // Load length directly from the JS array.

  __ Ret(USE_DELAY_SLOT);

  __ lw(v0, FieldMemOperand(receiver, JSArray::kLengthOffset));

}

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

// heap object, its map's instance type is left in the scratch1 register.

// If this is not needed, scratch1 and scratch2 may be the same register.

static void GenerateStringCheck(MacroAssembler* masm,

                                Register receiver,

                                Register scratch1,

                                Register scratch2,

                                Label* smi,

                                Label* non_string_object) {

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

  __ JumpIfSmi(receiver, smi, t0);

  // Check that the object is a string.

  __ lw(scratch1, FieldMemOperand(receiver, HeapObject::kMapOffset));

  __ lbu(scratch1, FieldMemOperand(scratch1, Map::kInstanceTypeOffset));

  __ And(scratch2, scratch1, Operand(kIsNotStringMask));

  // The cast is to resolve the overload for the argument of 0x0.

  __ Branch(non_string_object,

            ne,

            scratch2,

            Operand(static_cast<int32_t>(kStringTag)));

}

// Generate code to load the length from a string object and return the length.

// If the receiver object is not a string or a wrapped string object the

// execution continues at the miss label. The register containing the

// receiver is potentially clobbered.

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

  // scratch1 register.

  GenerateStringCheck(masm, receiver, scratch1, scratch2, miss, &check_wrapper);

  // Load length directly from the string.

  __ Ret(USE_DELAY_SLOT);

  __ lw(v0, FieldMemOperand(receiver, String::kLengthOffset));

  // Check if the object is a JSValue wrapper.

  __ bind(&check_wrapper);

  __ Branch(miss, ne, scratch1, Operand(JS_VALUE_TYPE));

  // Unwrap the value and check if the wrapped value is a string.

  __ lw(scratch1, FieldMemOperand(receiver, JSValue::kValueOffset));

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

  __ Ret(USE_DELAY_SLOT);

  __ lw(v0, FieldMemOperand(scratch1, String::kLengthOffset));

}

void StubCompiler::GenerateLoadFunctionPrototype(MacroAssembler* masm,

                                                 Register receiver,

                                                 Register scratch1,

                                                 Register scratch2,

                                                 Label* miss_label) {

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

  __ Ret(USE_DELAY_SLOT);

  __ mov(v0, scratch1);

}

// 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<Cell> cell = GlobalObject::EnsurePropertyCell(global, name);

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

  __ li(scratch, Operand(cell));

  __ lw(scratch, FieldMemOperand(scratch, Cell::kValueOffset));

  __ LoadRoot(at, Heap::kTheHoleValueRootIndex);

  __ Branch(miss, ne, scratch, Operand(at));

}

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());

  }

}

// Generate StoreTransition code, value is passed in a0 register.

// After executing generated code, the receiver_reg and name_reg

// may be clobbered.

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 scratch3,

                                                Label* miss_label,

                                                Label* slow) {

  // a0 : value.

  Label exit;

  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());

    __ LoadObject(scratch1, constant);

    __ Branch(miss_label, ne, value_reg, Operand(scratch1));

  } 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;

    __ LoadRoot(scratch3, Heap::kHeapNumberMapRootIndex);

    __ AllocateHeapNumber(storage_reg, scratch1, scratch2, scratch3, slow);

    __ JumpIfNotSmi(value_reg, &heap_number);

    __ SmiUntag(scratch1, value_reg);

    __ mtc1(scratch1, f6);

    __ cvt_d_w(f4, f6);

    __ jmp(&do_store);

    __ bind(&heap_number);

    __ CheckMap(value_reg, scratch1, Heap::kHeapNumberMapRootIndex,

                miss_label, DONT_DO_SMI_CHECK);

    __ ldc1(f4, FieldMemOperand(value_reg, HeapNumber::kValueOffset));

    __ bind(&do_store);

    __ sdc1(f4, FieldMemOperand(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.

    __ push(receiver_reg);

    __ li(a2, Operand(transition));

    __ Push(a2, a0);

    __ TailCallExternalReference(

           ExternalReference(IC_Utility(IC::kSharedStoreIC_ExtendStorage),

                             masm->isolate()),

           3, 1);

    return;

  }

  // Update the map of the object.

  __ li(scratch1, Operand(transition));

  __ sw(scratch1, FieldMemOperand(receiver_reg, HeapObject::kMapOffset));

  // Update the write barrier for the map field.

  __ RecordWriteField(receiver_reg,

                      HeapObject::kMapOffset,

                      scratch1,

                      scratch2,

                      kRAHasNotBeenSaved,

                      kDontSaveFPRegs,

                      OMIT_REMEMBERED_SET,

                      OMIT_SMI_CHECK);

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

    ASSERT(value_reg.is(a0));

    __ Ret(USE_DELAY_SLOT);

    __ mov(v0, a0);

    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();

  // 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);

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

      __ sw(storage_reg, FieldMemOperand(receiver_reg, offset));

    } else {

      __ sw(value_reg, FieldMemOperand(receiver_reg, offset));

    }

    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,

                          kRAHasNotBeenSaved,

                          kDontSaveFPRegs,

                          EMIT_REMEMBERED_SET,

                          smi_check);

    }

  } else {

    // Write to the properties array.

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

    // Get the properties array

    __ lw(scratch1,

          FieldMemOperand(receiver_reg, JSObject::kPropertiesOffset));

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

      __ sw(storage_reg, FieldMemOperand(scratch1, offset));

    } else {

      __ sw(value_reg, FieldMemOperand(scratch1, offset));

    }

    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,

                          kRAHasNotBeenSaved,

                          kDontSaveFPRegs,

                          EMIT_REMEMBERED_SET,

                          smi_check);

    }

  }

  // Return the value (register v0).

  ASSERT(value_reg.is(a0));

  __ bind(&exit);

  __ Ret(USE_DELAY_SLOT);

  __ mov(v0, a0);

}

// Generate StoreField code, value is passed in a0 register.

// When leaving generated code after success, the receiver_reg and name_reg

// may be clobbered.  Upon branch to miss_label, the receiver and name

// registers have their original values.

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) {

  // a0 : value

  Label exit;

  // 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);

      __ lw(scratch1, FieldMemOperand(receiver_reg, offset));

    } else {

      __ lw(scratch1,

            FieldMemOperand(receiver_reg, JSObject::kPropertiesOffset));

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

      __ lw(scratch1, FieldMemOperand(scratch1, offset));

    }

    // Store the value into the storage.

    Label do_store, heap_number;

    __ JumpIfNotSmi(value_reg, &heap_number);

    __ SmiUntag(scratch2, value_reg);

    __ mtc1(scratch2, f6);

    __ cvt_d_w(f4, f6);

    __ jmp(&do_store);

    __ bind(&heap_number);

    __ CheckMap(value_reg, scratch2, Heap::kHeapNumberMapRootIndex,

                miss_label, DONT_DO_SMI_CHECK);

    __ ldc1(f4, FieldMemOperand(value_reg, HeapNumber::kValueOffset));

    __ bind(&do_store);

    __ sdc1(f4, FieldMemOperand(scratch1, HeapNumber::kValueOffset));

    // Return the value (register v0).

    ASSERT(value_reg.is(a0));

    __ Ret(USE_DELAY_SLOT);

    __ mov(v0, a0);

    return;

  }

  // 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);

    __ sw(value_reg, FieldMemOperand(receiver_reg, offset));

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

      // Skip updating write barrier if storing a smi.

      __ JumpIfSmi(value_reg, &exit);

      // Update the write barrier for the array address.

      // Pass the now unused name_reg as a scratch register.

      __ mov(name_reg, value_reg);

      __ RecordWriteField(receiver_reg,

                          offset,

                          name_reg,

                          scratch1,

                          kRAHasNotBeenSaved,

                          kDontSaveFPRegs,

                          EMIT_REMEMBERED_SET,

                          smi_check);

    }

  } else {

    // Write to the properties array.

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

    // Get the properties array.

    __ lw(scratch1,

          FieldMemOperand(receiver_reg, JSObject::kPropertiesOffset));

    __ sw(value_reg, FieldMemOperand(scratch1, offset));

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

      // Skip updating write barrier if storing a smi.

      __ JumpIfSmi(value_reg, &exit);

      // Update the write barrier for the array address.

      // Ok to clobber receiver_reg and name_reg, since we return.

      __ mov(name_reg, value_reg);

      __ RecordWriteField(scratch1,

                          offset,

                          name_reg,

                          receiver_reg,

                          kRAHasNotBeenSaved,

                          kDontSaveFPRegs,

                          EMIT_REMEMBERED_SET,

                          smi_check);

    }

  }

  // Return the value (register v0).

  ASSERT(value_reg.is(a0));

  __ bind(&exit);

  __ Ret(USE_DELAY_SLOT);

  __ mov(v0, a0);

}

void StoreStubCompiler::GenerateRestoreName(MacroAssembler* masm,

                                            Label* label,

                                            Handle<Name> name) {

  if (!label->is_unused()) {

    __ bind(label);

    __ li(this->name(), Operand(name));

  }

}

static void GenerateCallFunction(MacroAssembler* masm,

                                 Handle<Object> object,

                                 const ParameterCount& arguments,

                                 Label* miss,

                                 Code::ExtraICState extra_ic_state) {

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

  //  -- a0: receiver

  //  -- a1: function to call

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

  // Check that the function really is a function.

  __ JumpIfSmi(a1, miss);

  __ GetObjectType(a1, a3, a3);

  __ Branch(miss, ne, a3, Operand(JS_FUNCTION_TYPE));

  // Patch the receiver on the stack with the global proxy if

  // necessary.

  if (object->IsGlobalObject()) {

    __ lw(a3, FieldMemOperand(a0, GlobalObject::kGlobalReceiverOffset));

    __ sw(a3, MemOperand(sp, arguments.immediate() * kPointerSize));

  }

  // Invoke the function.

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

      ? CALL_AS_FUNCTION

      : CALL_AS_METHOD;

  __ InvokeFunction(a1, arguments, JUMP_FUNCTION, NullCallWrapper(), call_kind);

}

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;

  __ li(scratch, Operand(interceptor));

  __ Push(scratch, receiver, holder);

}

static void CompileCallLoadPropertyWithInterceptor(

    MacroAssembler* masm,

    Register receiver,

    Register holder,

    Register name,

    Handle<JSObject> holder_obj) {

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

  ExternalReference ref =

      ExternalReference(IC_Utility(IC::kLoadPropertyWithInterceptorOnly),

          masm->isolate());

  __ PrepareCEntryArgs(StubCache::kInterceptorArgsLength);

  __ PrepareCEntryFunction(ref);

  CEntryStub stub(1);

  __ CallStub(&stub);

}

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 GenerateFastApiDirectCall.

static void ReserveSpaceForFastApiCall(MacroAssembler* masm,

                                       Register scratch) {

  ASSERT(Smi::FromInt(0) == 0);

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

    __ push(zero_reg);

  }

}

// Undoes the effects of ReserveSpaceForFastApiCall.

static void FreeSpaceForFastApiCall(MacroAssembler* masm) {

  __ Drop(kFastApiCallArguments);

}

static void GenerateFastApiDirectCall(MacroAssembler* masm,

                                      const CallOptimization& optimization,

                                      int argc,

                                      bool restore_context) {

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

  //  -- sp[0] - sp[24]     : FunctionCallbackInfo, incl.

  //                        :  holder (set by CheckPrototypes)

  //  -- sp[28]             : last JS argument

  //  -- ...

  //  -- sp[(argc + 6) * 4] : first JS argument

  //  -- sp[(argc + 7) * 4] : receiver

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

  typedef FunctionCallbackArguments FCA;

  // Save calling context.

  __ sw(cp, MemOperand(sp, FCA::kContextSaveIndex * kPointerSize));

  // Get the function and setup the context.

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

  __ LoadHeapObject(t1, function);

  __ lw(cp, FieldMemOperand(t1, JSFunction::kContextOffset));

  __ sw(t1, MemOperand(sp, FCA::kCalleeIndex * kPointerSize));

  // Construct the FunctionCallbackInfo.

  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)) {

    __ li(a0, api_call_info);

    __ lw(t2, FieldMemOperand(a0, CallHandlerInfo::kDataOffset));

  } else {

    __ li(t2, call_data);

  }

  // Store call data.

  __ sw(t2, MemOperand(sp, FCA::kDataIndex * kPointerSize));

  // Store isolate.

  __ li(t3, Operand(ExternalReference::isolate_address(masm->isolate())));

  __ sw(t3, MemOperand(sp, FCA::kIsolateIndex * kPointerSize));

  // Store ReturnValue default and ReturnValue.

  __ LoadRoot(t1, Heap::kUndefinedValueRootIndex);

  __ sw(t1, MemOperand(sp, FCA::kReturnValueOffset * kPointerSize));

  __ sw(t1, MemOperand(sp, FCA::kReturnValueDefaultValueIndex * kPointerSize));

  // Prepare arguments.

  __ Move(a2, sp);

  // Allocate the v8::Arguments structure in the arguments' space since

  // it's not controlled by GC.

  const int kApiStackSpace = 4;

  FrameScope frame_scope(masm, StackFrame::MANUAL);

  __ EnterExitFrame(false, kApiStackSpace);

  // a0 = FunctionCallbackInfo&

  // Arguments is built at sp + 1 (sp is a reserved spot for ra).

  __ Addu(a0, sp, kPointerSize);

  // FunctionCallbackInfo::implicit_args_

  __ sw(a2, MemOperand(a0, 0 * kPointerSize));

  // FunctionCallbackInfo::values_

  __ Addu(t0, a2, Operand((kFastApiCallArguments - 1 + argc) * kPointerSize));

  __ sw(t0, MemOperand(a0, 1 * kPointerSize));

  // FunctionCallbackInfo::length_ = argc

  __ li(t0, Operand(argc));

  __ sw(t0, MemOperand(a0, 2 * kPointerSize));

  // FunctionCallbackInfo::is_construct_call = 0

  __ sw(zero_reg, MemOperand(a0, 3 * kPointerSize));

  const int kStackUnwindSpace = argc + kFastApiCallArguments + 1;

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

  ApiFunction fun(function_address);

  ExternalReference::Type type = ExternalReference::DIRECT_API_CALL;

  ExternalReference ref =

      ExternalReference(&fun,

                        type,

                        masm->isolate());

  Address thunk_address = FUNCTION_ADDR(&InvokeFunctionCallback);

  ExternalReference::Type thunk_type = ExternalReference::PROFILING_API_CALL;

  ApiFunction thunk_fun(thunk_address);

  ExternalReference thunk_ref = ExternalReference(&thunk_fun, thunk_type,

      masm->isolate());

  AllowExternalCallThatCantCauseGC scope(masm);

  MemOperand context_restore_operand(

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

  MemOperand return_value_operand(

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

  __ CallApiFunctionAndReturn(ref,

                              function_address,

                              thunk_ref,

                              a1,

                              kStackUnwindSpace,

                              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));

  typedef FunctionCallbackArguments FCA;

  const int stack_space = kFastApiCallArguments + argc + 1;

  // Assign stack space for the call arguments.

  __ Subu(sp, sp, Operand(stack_space * kPointerSize));

  // Write holder to stack frame.

  __ sw(receiver, MemOperand(sp, FCA::kHolderIndex * kPointerSize));

  // Write receiver to stack frame.

  int index = stack_space - 1;

  __ sw(receiver, MemOperand(sp, index * kPointerSize));

  // Write the arguments to stack frame.

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

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

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

    __ sw(receiver, MemOperand(sp, index-- * kPointerSize));

  }

  GenerateFastApiDirectCall(masm, optimization, argc, true);

}

class CallInterceptorCompiler BASE_EMBEDDED {

 public:

  CallInterceptorCompiler(StubCompiler* stub_compiler,

                          const ParameterCount& arguments,

                          Register name,

                          Code::ExtraICState extra_ic_state)

      : stub_compiler_(stub_compiler),

        arguments_(arguments),

        name_(name),

        extra_ic_state_(extra_ic_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());

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

    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;

    }

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

                        scratch1, scratch2);

    if (can_do_fast_api_call) {

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

                          scratch1, scratch2);

      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, scratch2,

                        &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) {

      GenerateFastApiDirectCall(

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

    } else {

      CallKind call_kind = CallICBase::Contextual::decode(extra_ic_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);

      __ Branch(miss_label);

    }

    // Invoke a regular function.

    __ bind(&regular_invoke);

    if (can_do_fast_api_call) {

      FreeSpaceForFastApiCall(masm);

    }

  }

  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);

    // Call a runtime function to load the interceptor property.

    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,

                           Register scratch,

                           Label* interceptor_succeeded) {

    {

      FrameScope scope(masm, StackFrame::INTERNAL);

      __ Push(holder, name_);

      CompileCallLoadPropertyWithInterceptor(masm,

                                             receiver,

                                             holder,

                                             name_,

                                             holder_obj);

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

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

    }

    // If interceptor returns no-result sentinel, call the constant function.

    __ LoadRoot(scratch, Heap::kNoInterceptorResultSentinelRootIndex);

    __ Branch(interceptor_succeeded, ne, v0, Operand(scratch));

  }

  StubCompiler* stub_compiler_;

  const ParameterCount& arguments_;

  Register name_;

  Code::ExtraICState extra_ic_state_;

};

// 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) {

  __ Jump(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) {

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

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

  __ li(scratch1, Operand(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;

  int depth = 0;

  typedef FunctionCallbackArguments FCA;

  if (save_at_depth == depth) {

    __ sw(reg, MemOperand(sp, FCA::kHolderIndex * kPointerSize));

  }

  // Check the maps in the prototype chain.

  // Traverse the prototype chain from the object and do map checks.

  Handle<JSObject> current = object;

  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);

      __ lw(scratch1, FieldMemOperand(reg, HeapObject::kMapOffset));

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

      __ lw(reg, FieldMemOperand(scratch1, Map::kPrototypeOffset));

    } else {

      Register map_reg = scratch1;

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

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

        // CheckMap implicitly loads the map of |reg| into |map_reg|.

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

      } else {

        __ lw(map_reg, FieldMemOperand(reg, HeapObject::kMapOffset));

      }

      // 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, scratch2, miss);

      }

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

      if (heap()->InNewSpace(*prototype)) {

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

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

        __ lw(reg, FieldMemOperand(map_reg, Map::kPrototypeOffset));

      } else {

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

        __ li(reg, Operand(prototype));

      }

    }

    if (save_at_depth == depth) {

      __ sw(reg, MemOperand(sp, FCA::kHolderIndex * kPointerSize));

    }

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

    current = prototype;

  }

  // 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, scratch1, 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, 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()) {

    __ Branch(success);

    __ bind(miss);

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

  }

}

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

                                              Label* success,

                                              Label* miss) {

  if (!miss->is_unused()) {

    __ b(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()));

    ASSERT(!reg.is(scratch4()));

    // Load the properties dictionary.

    Register dictionary = scratch4();

    __ lw(dictionary, FieldMemOperand(reg, JSObject::kPropertiesOffset));

    // Probe the dictionary.

    Label probe_done;

    NameDictionaryLookupStub::GeneratePositiveLookup(masm(),

                                                     &miss,

                                                     &probe_done,

                                                     dictionary,

                                                     this->name(),

                                                     scratch2(),

                                                     scratch3());

    __ bind(&probe_done);

    // If probing finds an entry in the dictionary, scratch3 contains the

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

    Register pointer = scratch3();

    const int kElementsStartOffset = NameDictionary::kHeaderSize +

        NameDictionary::kElementsStartIndex * kPointerSize;

    const int kValueOffset = kElementsStartOffset + kPointerSize;

    __ lw(scratch2(), FieldMemOperand(pointer, kValueOffset));

    __ Branch(&miss, ne, scratch2(), Operand(callback));

  }

  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::GenerateLoadConstant(Handle<Object> value) {

  // Return the constant value.

  __ LoadObject(v0, value);

  __ Ret();

}

void LoadStubCompiler::GenerateLoadCallback(

    const CallOptimization& call_optimization) {

  GenerateFastApiCall(

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

}

void LoadStubCompiler::GenerateLoadCallback(

    Register reg,

    Handle<ExecutableAccessorInfo> callback) {

  // Build AccessorInfo::args_ list on the stack and push property name below

  // the exit frame to make GC aware of them and store pointers to them.

  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);

  STATIC_ASSERT(PropertyCallbackArguments::kArgsLength == 6);

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

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

  ASSERT(!scratch4().is(reg));

  __ push(receiver());

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

    __ li(scratch3(), callback);

    __ lw(scratch3(), FieldMemOperand(scratch3(),

                                      ExecutableAccessorInfo::kDataOffset));

  } else {

    __ li(scratch3(), Handle<Object>(callback->data(), isolate()));

  }

  __ Subu(sp, sp, 6 * kPointerSize);

  __ sw(scratch3(), MemOperand(sp, 5 * kPointerSize));

  __ LoadRoot(scratch3(), Heap::kUndefinedValueRootIndex);

  __ sw(scratch3(), MemOperand(sp, 4 * kPointerSize));

  __ sw(scratch3(), MemOperand(sp, 3 * kPointerSize));

  __ li(scratch4(),

        Operand(ExternalReference::isolate_address(isolate())));

  __ sw(scratch4(), MemOperand(sp, 2 * kPointerSize));

  __ sw(reg, MemOperand(sp, 1 * kPointerSize));

  __ sw(name(), MemOperand(sp, 0 * kPointerSize));

  __ Addu(scratch2(), sp, 1 * kPointerSize);

  __ mov(a2, scratch2());  // Saved in case scratch2 == a1.

  __ mov(a0, sp);  // (first argument - a0) = Handle<Name>

  const int kApiStackSpace = 1;

  FrameScope frame_scope(masm(), StackFrame::MANUAL);

  __ EnterExitFrame(false, kApiStackSpace);

  // Create PropertyAccessorInfo instance on the stack above the exit frame with

  // scratch2 (internal::Object** args_) as the data.

  __ sw(a2, MemOperand(sp, kPointerSize));

  // (second argument - a1) = AccessorInfo&

  __ Addu(a1, sp, kPointerSize);

  const int kStackUnwindSpace = PropertyCallbackArguments::kArgsLength + 1;

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

  ApiFunction fun(getter_address);

  ExternalReference::Type type = ExternalReference::DIRECT_GETTER_CALL;

  ExternalReference ref = ExternalReference(&fun, type, isolate());

  Address thunk_address = FUNCTION_ADDR(&InvokeAccessorGetterCallback);

  ExternalReference::Type thunk_type =

      ExternalReference::PROFILING_GETTER_CALL;

  ApiFunction thunk_fun(thunk_address);