Use Cells to check prototype chain validity (disabled by default).

src/objects.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 1813 matching lines @@
                                     Handle<Object> value,
                                     PropertyDetails details);
 
   static void OptimizeAsPrototype(Handle<JSObject> object,
                                   PrototypeOptimizationMode mode);
   static void ReoptimizeIfPrototype(Handle<JSObject> object);
   static void RegisterPrototypeUser(Handle<JSObject> prototype,
                                     Handle<HeapObject> user);
   static void UnregisterPrototypeUser(Handle<JSObject> prototype,
                                       Handle<HeapObject> user);
+  static void InvalidatePrototypeChains(Map* map);
 
   // Retrieve interceptors.
   InterceptorInfo* GetNamedInterceptor();
   InterceptorInfo* GetIndexedInterceptor();
 
   // Used from JSReceiver.
   MUST_USE_RESULT static Maybe<PropertyAttributes>
       GetPropertyAttributesWithInterceptor(Handle<JSObject> holder,
                                            Handle<Object> receiver,
                                            Handle<Name> name);
@@ skipping 4134 matching lines @@
   inline FixedArrayBase* GetInitialElements();
 
   // [raw_transitions]: Provides access to the transitions storage field.
   // Don't call set_raw_transitions() directly to overwrite transitions, use
   // the TransitionArray::ReplaceTransitions() wrapper instead!
   DECL_ACCESSORS(raw_transitions, Object)
   // [prototype_info]: Per-prototype metadata. Aliased with transitions
   // (which prototype maps don't have).
   DECL_ACCESSORS(prototype_info, Object)
 
+  // [prototype chain validity cell]: Associated with a prototype object,
+  // stored in that object's map's PrototypeInfo, indicates that prototype
+  // chains through this object are currently valid. The cell will be
+  // invalidated and replaced when the prototype chain changes.
+  static Handle<Cell> GetOrCreatePrototypeChainValidityCell(Handle<Map> map,
+                                                            Isolate* isolate);
+  static const int kPrototypeChainValid = 0;
+  static const int kPrototypeChainInvalid = 1;
+
   Map* FindRootMap();
   Map* FindFieldOwner(int descriptor);
 
   inline int GetInObjectPropertyOffset(int index);
 
   int NumberOfFields();
 
   // TODO(ishell): candidate with JSObject::MigrateToMap().
   bool InstancesNeedRewriting(Map* target, int target_number_of_fields,
                               int target_inobject, int target_unused,
@@ skipping 5041 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_