Make maps in monomorphic IC stubs weak.

src/ic.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 88 matching lines @@
 
   bool IsNameCompatibleWithMonomorphicPrototypeFailure(Handle<Object> name);
   bool TryMarkMonomorphicPrototypeFailure(Handle<Object> name) {
     if (IsNameCompatibleWithMonomorphicPrototypeFailure(name)) {
       state_ = MONOMORPHIC_PROTOTYPE_FAILURE;
       return true;
     }
     return false;
   }
 
+  // If the stub contains weak maps then this function adds the stub to
+  // the dependent code array of each weak map.
+  static void RegisterWeakMapDependency(Handle<Code> stub);
+
+  // This function is called when a weak map in the stub is dying,
+  // invalidates the stub by setting maps in it to undefined.
+  static void InvalidateMaps(Code* stub);
+
   // Clear the inline cache to initial state.
   static void Clear(Isolate* isolate,
                     Address address,
                     ConstantPoolArray* constant_pool);
 
 #ifdef DEBUG
   bool IsLoadStub() const {
     return target()->is_load_stub() || target()->is_keyed_load_stub();
   }
 
@@ skipping 47 matching lines @@
   // Get the shared function info of the caller.
   SharedFunctionInfo* GetSharedFunctionInfo() const;
   // Get the code object of the caller.
   Code* GetCode() const;
   // Get the original (non-breakpointed) code object of the caller.
   Code* GetOriginalCode() const;
 #endif
 
   // Set the call-site target.
   void set_target(Code* code) {
+#ifdef VERIFY_HEAP
+    code->VerifyEmbeddedObjectsDependency();
+#endif
     SetTargetAtAddress(address(), code, constant_pool());
     target_set_ = true;
   }
 
   bool is_target_set() { return target_set_; }
 
 #ifdef DEBUG
   char TransitionMarkFromState(IC::State state);
 
   void TraceIC(const char* type, Handle<Object> name);
@@ skipping 779 matching lines @@
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, ElementsTransitionAndStoreIC_Miss);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, BinaryOpIC_Miss);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, BinaryOpIC_MissWithAllocationSite);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, CompareNilIC_Miss);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, ToBooleanIC_Miss);
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_IC_H_