Load API holder from prototype chain instead embedding it in handler.

src/ic/call-optimization.cc

 // 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.
 
 #include "src/v8.h"
 
 #include "src/ic/call-optimization.h"
 
 
 namespace v8 {
 namespace internal {
 
 CallOptimization::CallOptimization(Handle<JSFunction> function) {
   Initialize(function);
 }
 
 
 Handle<JSObject> CallOptimization::LookupHolderOfExpectedType(
-    Handle<Map> object_map, HolderLookup* holder_lookup) const {
+    Handle<Map> object_map, HolderLookup* holder_lookup,
+    int* holder_depth_in_prototype_chain) const {
   DCHECK(is_simple_api_call());
   if (!object_map->IsJSObjectMap()) {
     *holder_lookup = kHolderNotFound;
     return Handle<JSObject>::null();
   }
   if (expected_receiver_type_.is_null() ||
       expected_receiver_type_->IsTemplateFor(*object_map)) {
     *holder_lookup = kHolderIsReceiver;
     return Handle<JSObject>::null();
   }
-  while (true) {
+  for (int depth = 1; true; depth++) {
     if (!object_map->prototype()->IsJSObject()) break;
     Handle<JSObject> prototype(JSObject::cast(object_map->prototype()));
     if (!prototype->map()->is_hidden_prototype()) break;
     object_map = handle(prototype->map());
     if (expected_receiver_type_->IsTemplateFor(*object_map)) {
       *holder_lookup = kHolderFound;
+      if (holder_depth_in_prototype_chain != NULL) {
+        *holder_depth_in_prototype_chain = depth;
+      }
       return prototype;
     }
   }
   *holder_lookup = kHolderNotFound;
   return Handle<JSObject>::null();
 }
 
 
 bool CallOptimization::IsCompatibleReceiver(Handle<Object> receiver,
                                             Handle<JSObject> holder) const {
@@ skipping 49 matching lines @@
 
   if (!info->signature()->IsUndefined()) {
     expected_receiver_type_ =
         handle(FunctionTemplateInfo::cast(info->signature()));
   }
 
   is_simple_api_call_ = true;
 }
 }
 }  // namespace v8::internal