Enable weak embedded maps in optimized code.

src/mark-compact.h

 // 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 835 matching lines @@
   void ProcessMarkingDeque();
 
   // Mark objects reachable (transitively) from objects in the marking stack
   // or overflowed in the heap.  This respects references only considered in
   // the final atomic marking pause including the following:
   //    - Processing of objects reachable through Harmony WeakMaps.
   //    - Objects reachable due to host application logic like object groups
   //      or implicit references' groups.
   void ProcessEphemeralMarking(ObjectVisitor* visitor);
 
+  // If the call-site of the top optimized code was not prepared for
+  // deoptimization, then treat the maps in the code as strong pointers,
+  // otherwise a map can die and deoptimize the code.
+  void ProcessTopOptimizedFrame(ObjectVisitor* visitor);
+
   // Mark objects reachable (transitively) from objects in the marking
   // stack.  This function empties the marking stack, but may leave
   // overflowed objects in the heap, in which case the marking stack's
   // overflow flag will be set.
   void EmptyMarkingDeque();
 
   // Refill the marking stack with overflowed objects from the heap.  This
   // function either leaves the marking stack full or clears the overflow
   // flag on the marking stack.
   void RefillMarkingDeque();
@@ skipping 92 matching lines @@
  private:
   MarkCompactCollector* collector_;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 
 } }  // namespace v8::internal
 
 #endif  // V8_MARK_COMPACT_H_