Store JSGlobalProxy's identity hash directly on the proxy itself

src/objects.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 2110 matching lines @@
 
   enum KeyCollectionType { LOCAL_ONLY, INCLUDE_PROTOS };
 
   // Computes the enumerable keys for a JSObject. Used for implementing
   // "for (n in object) { }".
   MUST_USE_RESULT static MaybeHandle<FixedArray> GetKeys(
       Handle<JSReceiver> object,
       KeyCollectionType type);
 
  protected:
-  Smi* GenerateIdentityHash();
-
   MUST_USE_RESULT static MaybeHandle<Object> SetPropertyWithDefinedSetter(
       Handle<JSReceiver> object,
       Handle<JSReceiver> setter,
       Handle<Object> value);
 
  private:
   static PropertyAttributes GetPropertyAttributeForResult(
       Handle<JSReceiver> object,
       Handle<JSReceiver> receiver,
       LookupResult* result,
@@ skipping 5704 matching lines @@
 // A JSGlobalProxy can be reinitialized which will preserve its identity.
 //
 // Accessing a JSGlobalProxy requires security check.
 
 class JSGlobalProxy : public JSObject {
  public:
   // [native_context]: the owner native context of this global proxy object.
   // It is null value if this object is not used by any context.
   DECL_ACCESSORS(native_context, Object)
 
+  // [hash]: The hash code property (undefined if not initialized yet).
+  DECL_ACCESSORS(hash, Object)
+
   // Casting.
   static inline JSGlobalProxy* cast(Object* obj);
 
   inline bool IsDetachedFrom(GlobalObject* global);
 
   // Dispatched behavior.
   DECLARE_PRINTER(JSGlobalProxy)
   DECLARE_VERIFIER(JSGlobalProxy)
 
   // Layout description.
   static const int kNativeContextOffset = JSObject::kHeaderSize;
-  static const int kSize = kNativeContextOffset + kPointerSize;
+  static const int kHashOffset = kNativeContextOffset + kPointerSize;
+  static const int kSize = kHashOffset + kPointerSize;
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(JSGlobalProxy);
 };
 
 
 // Forward declaration.
 class JSBuiltinsObject;
 
 // Common super class for JavaScript global objects and the special
@@ skipping 3400 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_