Add map-based read barrier to WeakCell

src/objects-debug.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/disasm.h"
 #include "src/disassembler.h"
 #include "src/heap/objects-visiting.h"
 #include "src/jsregexp.h"
 #include "src/macro-assembler.h"
+#include "src/objects-inl.h"
 #include "src/ostreams.h"
 
 namespace v8 {
 namespace internal {
 
 #ifdef VERIFY_HEAP
 
 void Object::ObjectVerify() {
   if (IsSmi()) {
     Smi::cast(this)->SmiVerify();
@@ skipping 618 matching lines @@
 
 void PropertyCell::PropertyCellVerify() {
   CHECK(IsPropertyCell());
   VerifyObjectField(kValueOffset);
   VerifyObjectField(kTypeOffset);
 }
 
 
 void WeakCell::WeakCellVerify() {
   CHECK(IsWeakCell());
-  VerifyObjectField(kValueOffset);
+  Object* value = ValueNoReadBarrier();
+  VerifyPointer(value);
   VerifyObjectField(kNextOffset);
 }
 
 
 void Code::CodeVerify() {
   CHECK(IsAligned(reinterpret_cast<intptr_t>(instruction_start()),
                   kCodeAlignment));
   relocation_info()->ObjectVerify();
   Address last_gc_pc = NULL;
   Isolate* isolate = GetIsolate();
@@ skipping 589 matching lines @@
     while (map != heap->roots_array_start()[i++]) {
       CHECK_LT(i, Heap::kStrongRootListLength);
     }
   }
 }
 
 
 #endif  // DEBUG
 
 } }  // namespace v8::internal