Cache IC handlers on the prototype's map if possible

src/property.h

 // Copyright 2014 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_PROPERTY_H_
 #define V8_PROPERTY_H_
 
 #include "src/factory.h"
 #include "src/field-index.h"
 #include "src/field-index-inl.h"
@@ skipping 442 matching lines @@
     return GetFieldOwnerFromMap(holder()->map());
   }
 
   Map* GetFieldOwnerFromMap(Map* map) const {
     ASSERT(lookup_type_ == DESCRIPTOR_TYPE ||
            lookup_type_ == TRANSITION_TYPE);
     ASSERT(number_ < map->NumberOfOwnDescriptors());
     return map->FindFieldOwner(number_);
   }
 
+  bool ReceiverIsHolder(Handle<Object> receiver) {
+    if (*receiver == holder()) return true;
+    if (lookup_type_ == TRANSITION_TYPE) return true;
+    return false;
+  }
+
   void Iterate(ObjectVisitor* visitor);
 
  private:
   Isolate* isolate_;
   LookupResult* next_;
 
   // Where did we find the result;
   enum {
     NOT_FOUND,
     DESCRIPTOR_TYPE,
     TRANSITION_TYPE,
     DICTIONARY_TYPE,
     HANDLER_TYPE,
     INTERCEPTOR_TYPE
   } lookup_type_;
 
   JSReceiver* holder_;
   Map* transition_;
   int number_;
   bool cacheable_;
   PropertyDetails details_;
 };
 
 
 OStream& operator<<(OStream& os, const LookupResult& r);
 } }  // namespace v8::internal
 
 #endif  // V8_PROPERTY_H_