Eliminate RawObject::class_ field entirely.

runtime/vm/assembler_macros_x64.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler_macros.h"
 
 #include "vm/assembler.h"
 
 namespace dart {
 
 DECLARE_FLAG(bool, inline_alloc);
 
 #define __ assembler->
 
 // Static.
 void AssemblerMacros::TryAllocate(Assembler* assembler,
                                   const Class& cls,
-                                  Register class_reg,
                                   Label* failure,
                                   Register instance_reg) {
 #if defined(DEBUG)
   __ Untested("AssemblerMacros::TryAllocate");
-  Label ok;
-  __ LoadObject(instance_reg, cls);
-  __ cmpq(instance_reg, class_reg);
-  __ j(EQUAL, &ok, Assembler::kNearJump);
-  __ Stop("AssemblerMacros::TryAllocate, wrong arguments");
-  __ Bind(&ok);
 #endif
   ASSERT(failure != NULL);
-  ASSERT(class_reg != instance_reg);
   if (FLAG_inline_alloc) {
     Heap* heap = Isolate::Current()->heap();
     const intptr_t instance_size = cls.instance_size();
     __ movq(TMP, Immediate(heap->TopAddress()));
     __ movq(instance_reg, Address(TMP, 0));
     __ addq(instance_reg, Immediate(instance_size));
     // instance_reg: potential next object start.
     __ movq(TMP, Immediate(heap->EndAddress()));
     __ cmpq(instance_reg, Address(TMP, 0));
     __ j(ABOVE_EQUAL, failure, Assembler::kNearJump);
     // Successfully allocated the object, now update top to point to
     // next object start and store the class in the class field of object.
     __ movq(TMP, Immediate(heap->TopAddress()));
     __ movq(Address(TMP, 0), instance_reg);
     ASSERT(instance_size >= kHeapObjectTag);
     __ subq(instance_reg, Immediate(instance_size - kHeapObjectTag));
-    __ StoreIntoObject(instance_reg,
-                       FieldAddress(instance_reg, Instance::class_offset()),
-                       class_reg);
     uword tags = 0;
     tags = RawObject::SizeTag::update(instance_size, tags);
     ASSERT(cls.id() != kIllegalObjectKind);
     tags = RawObject::ClassIdTag::update(cls.id(), tags);
     __ movq(FieldAddress(instance_reg, Object::tags_offset()), Immediate(tags));
   } else {
     __ jmp(failure);
   }
 }
 
@@ skipping 19 matching lines @@
 void AssemblerMacros::EnterStubFrame(Assembler* assembler) {
   __ EnterFrame(0);
   __ pushq(Immediate(0));  // Push 0 in the saved PC area for stub frames.
 }
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64