Revert "Remove Code::active_instructions_."

runtime/vm/object.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/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 13491 matching lines @@
 
 bool Code::IsFunctionCode() const {
   const Object& obj = Object::Handle(owner());
   return obj.IsFunction();
 }
 
 
 void Code::DisableDartCode() const {
   DEBUG_ASSERT(IsMutatorOrAtSafepoint());
   ASSERT(IsFunctionCode());
-  ASSERT(!IsDisabled());
+  ASSERT(instructions() == active_instructions());
   const Code& new_code =
       Code::Handle(StubCode::FixCallersTarget_entry()->code());
-  ASSERT(new_code.instructions()->IsVMHeapObject());
   SetActiveInstructions(new_code.instructions());
 }
 
 
 void Code::DisableStubCode() const {
   ASSERT(Thread::Current()->IsMutatorThread());
   ASSERT(IsAllocationStubCode());
-  ASSERT(!IsDisabled());
+  ASSERT(instructions() == active_instructions());
   const Code& new_code =
       Code::Handle(StubCode::FixAllocationStubTarget_entry()->code());
-  ASSERT(new_code.instructions()->IsVMHeapObject());
   SetActiveInstructions(new_code.instructions());
 }
 
 
 void Code::SetActiveInstructions(RawInstructions* instructions) const {
   DEBUG_ASSERT(IsMutatorOrAtSafepoint() || !is_alive());
   // RawInstructions are never allocated in New space and hence a
   // store buffer update is not needed here.
+  StorePointer(&raw_ptr()->active_instructions_, instructions);
   StoreNonPointer(&raw_ptr()->entry_point_,
                   reinterpret_cast<uword>(instructions->ptr()) +
                   Instructions::HeaderSize());
 }
 
 
 uword Code::GetLazyDeoptPc() const {
   return (lazy_deopt_pc_offset() != kInvalidPc)
       ? EntryPoint() + lazy_deopt_pc_offset() : 0;
 }
@@ skipping 8409 matching lines @@
   return UserTag::null();
 }
 
 
 const char* UserTag::ToCString() const {
   const String& tag_label = String::Handle(label());
   return tag_label.ToCString();
 }
 
 }  // namespace dart