Add support for WritableRegister policy in the register allocator.

runtime/vm/assembler_x64.cc

 // Copyright (c) 2012, 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.h"
 #include "vm/heap.h"
 #include "vm/memory_region.h"
@@ skipping 1576 matching lines @@
   cmpl(value, Immediate(
       (kNewObjectAlignmentOffset >> 1) + kHeapObjectTag +
       kOldObjectAlignmentOffset + kHeapObjectTag));
   j(NOT_ZERO, no_update, Assembler::kNearJump);
 }
 
 
 void Assembler::StoreIntoObject(Register object,
                                 const FieldAddress& dest,
                                 Register value) {
-  // TODO(kmillikin): pass temp registers to avoid pushing registers.
+  ASSERT(object != value);
   movq(dest, value);
-
   Label done;
-  pushq(value);
   StoreIntoObjectFilter(object, value, &done);
   // A store buffer update is required.
   if (value != RAX) pushq(RAX);
   leaq(RAX, dest);
   call(&StubCode::UpdateStoreBufferLabel());
   if (value != RAX) popq(RAX);
   Bind(&done);
-  popq(value);
 }
 
 
 void Assembler::StoreIntoObjectNoBarrier(Register object,
                                          const FieldAddress& dest,
                                          Register value) {
   movq(dest, value);
 #if defined(DEBUG)
   Label done;
   pushq(value);
@@ skipping 367 matching lines @@
 
 const char* Assembler::XmmRegisterName(XmmRegister reg) {
   ASSERT((0 <= reg) && (reg < kNumberOfXmmRegisters));
   return xmm_reg_names[reg];
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64