Prevent false positive from GCMole in DeferredFormatStackTrace.

src/heap.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 7678 matching lines @@
       // Check whether the stack property is backed by the original getter.
       LookupResult lookup(isolate);
       JSObject::cast(object)->LocalLookupRealNamedProperty(*stack_key, &lookup);
       if (!lookup.IsFound() || lookup.type() != CALLBACKS) continue;
       Object* callback = lookup.GetCallbackObject();
       if (!callback->IsAccessorPair()) continue;
       Object* getter_obj = AccessorPair::cast(callback)->getter();
       if (!getter_obj->IsJSFunction()) continue;
       getter_fun = JSFunction::cast(getter_obj);
       String* key = isolate->heap()->hidden_stack_trace_string();
-      if (key != getter_fun->GetHiddenProperty(key)) continue;
+      Object* value = getter_fun->GetHiddenProperty(key);
+      if (key != value) continue;
     }
 
     budget--;
     HandleScope scope(isolate);
     bool has_exception = false;
 #ifdef DEBUG
     Handle<Map> map(HeapObject::cast(object)->map(), isolate);
 #endif
     Handle<Object> object_handle(object, isolate);
     Handle<Object> getter_handle(getter_fun, isolate);
@@ skipping 150 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   FIXED_ARRAY_SUB_INSTANCE_TYPE_LIST(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   OS::MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   OS::MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 
 } }  // namespace v8::internal