Add zapping of Map contents in debug mode.

src/objects-debug.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 974 matching lines @@
       if (e->IsMap()) {
         Map::cast(e)->SharedMapVerify();
       } else {
         ASSERT(e->IsUndefined());
       }
     }
   }
 }
 
 
+void Map::ZapInstanceDescriptors() {
+  DescriptorArray* descriptors = instance_descriptors();
+  if (descriptors == GetHeap()->empty_descriptor_array()) return;
+  FixedArray* contents = FixedArray::cast(
+      descriptors->get(DescriptorArray::kContentArrayIndex));
+  MemsetPointer(descriptors->data_start(),
+                GetHeap()->the_hole_value(),
+                descriptors->length());
+  MemsetPointer(contents->data_start(),
+                GetHeap()->the_hole_value(),
+                contents->length());
+}
+
+
+void Map::ZapPrototypeTransitions() {
+  FixedArray* proto_transitions = prototype_transitions();
+  MemsetPointer(proto_transitions->data_start(),
+                GetHeap()->the_hole_value(),
+                proto_transitions->length());
+}
+
+
 #endif  // DEBUG
 
 } }  // namespace v8::internal