| Index: src/ia32/lithium-codegen-ia32.cc | 
| diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc | 
| index 225584a83d536ce7c4207de712b2eadbc5ddae12..b000e58cab40371e39af05df30666e136626ad54 100644 | 
| --- a/src/ia32/lithium-codegen-ia32.cc | 
| +++ b/src/ia32/lithium-codegen-ia32.cc | 
| @@ -4260,26 +4260,36 @@ void LCodeGen::EmitDeepCopy(Handle<JSObject> object, | 
| __ Assert(equal, "Unexpected object literal boilerplate"); | 
| } | 
|  | 
| +  // Only elements backing stores for non-cow arrays need to be copied. | 
| +  Handle<FixedArrayBase> elements(object->elements()); | 
| +  bool has_elements = elements->length() > 0 && | 
| +      elements->map() != isolate()->heap()->fixed_cow_array_map(); | 
| + | 
| // Increase the offset so that subsequent objects end up right after | 
| -  // this one. | 
| -  int current_offset = *offset; | 
| -  int size = object->map()->instance_size(); | 
| -  *offset += size; | 
| +  // this object and its backing store. | 
| +  int object_offset = *offset; | 
| +  int object_size = object->map()->instance_size(); | 
| +  int elements_offset = *offset + object_size; | 
| +  int elements_size = has_elements ? elements->Size() : 0; | 
| +  *offset += object_size + elements_size; | 
|  | 
| // Copy object header. | 
| ASSERT(object->properties()->length() == 0); | 
| -  ASSERT(object->elements()->length() == 0 || | 
| -         object->elements()->map() == isolate()->heap()->fixed_cow_array_map()); | 
| int inobject_properties = object->map()->inobject_properties(); | 
| -  int header_size = size - inobject_properties * kPointerSize; | 
| +  int header_size = object_size - inobject_properties * kPointerSize; | 
| for (int i = 0; i < header_size; i += kPointerSize) { | 
| -    __ mov(ecx, FieldOperand(source, i)); | 
| -    __ mov(FieldOperand(result, current_offset + i), ecx); | 
| +    if (has_elements && i == JSObject::kElementsOffset) { | 
| +      __ lea(ecx, Operand(result, elements_offset)); | 
| +      __ mov(FieldOperand(result, object_offset + i), ecx); | 
| +    } else { | 
| +      __ mov(ecx, FieldOperand(source, i)); | 
| +      __ mov(FieldOperand(result, object_offset + i), ecx); | 
| +    } | 
| } | 
|  | 
| // Copy in-object properties. | 
| for (int i = 0; i < inobject_properties; i++) { | 
| -    int total_offset = current_offset + object->GetInObjectPropertyOffset(i); | 
| +    int total_offset = object_offset + object->GetInObjectPropertyOffset(i); | 
| Handle<Object> value = Handle<Object>(object->InObjectPropertyAt(i)); | 
| if (value->IsJSObject()) { | 
| Handle<JSObject> value_object = Handle<JSObject>::cast(value); | 
| @@ -4294,10 +4304,40 @@ void LCodeGen::EmitDeepCopy(Handle<JSObject> object, | 
| __ mov(FieldOperand(result, total_offset), Immediate(value)); | 
| } | 
| } | 
| + | 
| +  // Copy elements backing store header. | 
| +  ASSERT(!has_elements || elements->IsFixedArray()); | 
| +  if (has_elements) { | 
| +    __ LoadHeapObject(source, elements); | 
| +    for (int i = 0; i < FixedArray::kHeaderSize; i += kPointerSize) { | 
| +      __ mov(ecx, FieldOperand(source, i)); | 
| +      __ mov(FieldOperand(result, elements_offset + i), ecx); | 
| +    } | 
| +  } | 
| + | 
| +  // Copy elements backing store content. | 
| +  ASSERT(!has_elements || elements->IsFixedArray()); | 
| +  int elements_length = has_elements ? elements->length() : 0; | 
| +  for (int i = 0; i < elements_length; i++) { | 
| +    int total_offset = elements_offset + FixedArray::OffsetOfElementAt(i); | 
| +    Handle<Object> value = JSObject::GetElement(object, i); | 
| +    if (value->IsJSObject()) { | 
| +      Handle<JSObject> value_object = Handle<JSObject>::cast(value); | 
| +      __ lea(ecx, Operand(result, *offset)); | 
| +      __ mov(FieldOperand(result, total_offset), ecx); | 
| +      __ LoadHeapObject(source, value_object); | 
| +      EmitDeepCopy(value_object, result, source, offset); | 
| +    } else if (value->IsHeapObject()) { | 
| +      __ LoadHeapObject(ecx, Handle<HeapObject>::cast(value)); | 
| +      __ mov(FieldOperand(result, total_offset), ecx); | 
| +    } else { | 
| +      __ mov(FieldOperand(result, total_offset), Immediate(value)); | 
| +    } | 
| +  } | 
| } | 
|  | 
|  | 
| -void LCodeGen::DoObjectLiteralFast(LObjectLiteralFast* instr) { | 
| +void LCodeGen::DoFastLiteral(LFastLiteral* instr) { | 
| ASSERT(ToRegister(instr->context()).is(esi)); | 
| int size = instr->hydrogen()->total_size(); | 
|  | 
| @@ -4319,7 +4359,7 @@ void LCodeGen::DoObjectLiteralFast(LObjectLiteralFast* instr) { | 
| } | 
|  | 
|  | 
| -void LCodeGen::DoObjectLiteralGeneric(LObjectLiteralGeneric* instr) { | 
| +void LCodeGen::DoObjectLiteral(LObjectLiteral* instr) { | 
| ASSERT(ToRegister(instr->context()).is(esi)); | 
| Handle<FixedArray> literals(instr->environment()->closure()->literals()); | 
| Handle<FixedArray> constant_properties = | 
|  |