Introduce a PrototypeIterator class and use it for prototype access

src/ic-inl.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_IC_INL_H_
 #define V8_IC_INL_H_
 
 #include "src/ic.h"
 
 #include "src/compiler.h"
 #include "src/debug.h"
 #include "src/macro-assembler.h"
+#include "src/prototype.h"
 
 namespace v8 {
 namespace internal {
 
 
 Address IC::address() const {
   // Get the address of the call.
   Address result = Assembler::target_address_from_return_address(pc());
 
   Debug* debug = isolate()->debug();
@@ skipping 102 matching lines @@
   ASSERT(object->IsString() || object->IsSymbol() ||
          object->IsNumber() || object->IsBoolean());
   return PROTOTYPE_MAP;
 }
 
 
 HeapObject* IC::GetCodeCacheHolder(Isolate* isolate,
                                    Object* object,
                                    InlineCacheHolderFlag holder) {
   if (object->IsSmi()) holder = PROTOTYPE_MAP;
-  Object* map_owner = holder == OWN_MAP
-      ? object : object->GetPrototype(isolate);
-  return HeapObject::cast(map_owner);
+  PrototypeIterator iter(isolate, object,
+                         holder == OWN_MAP
+                             ? PrototypeIterator::START_AT_RECEIVER
+                             : PrototypeIterator::START_AT_PROTOTYPE);
+  return HeapObject::cast(iter.GetCurrent());
 }
 
 
 InlineCacheHolderFlag IC::GetCodeCacheFlag(HeapType* type) {
   if (type->Is(HeapType::Boolean()) ||
       type->Is(HeapType::Number()) ||
       type->Is(HeapType::String()) ||
       type->Is(HeapType::Symbol())) {
     return PROTOTYPE_MAP;
   }
@@ skipping 19 matching lines @@
     }
     return handle(JSObject::cast(constructor->instance_prototype())->map());
   }
   return TypeToMap(type, isolate);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_IC_INL_H_