Introduce a PrototypeIterator class and use it for prototype access

src/isolate.cc

 // 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.
 
 #include <stdlib.h>
 
 #include "src/v8.h"
 
 #include "src/ast.h"
 #include "src/base/platform/platform.h"
 #include "src/base/utils/random-number-generator.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
 #include "src/compilation-cache.h"
 #include "src/cpu-profiler.h"
 #include "src/debug.h"
 #include "src/deoptimizer.h"
 #include "src/heap-profiler.h"
 #include "src/hydrogen.h"
 #include "src/isolate-inl.h"
 #include "src/lithium-allocator.h"
 #include "src/log.h"
 #include "src/messages.h"
+#include "src/prototype.h"
 #include "src/regexp-stack.h"
 #include "src/runtime-profiler.h"
 #include "src/sampler.h"
 #include "src/scopeinfo.h"
 #include "src/serialize.h"
 #include "src/simulator.h"
 #include "src/spaces.h"
 #include "src/stub-cache.h"
 #include "src/sweeper-thread.h"
 #include "src/version.h"
@@ skipping 941 matching lines @@
 
 bool Isolate::IsErrorObject(Handle<Object> obj) {
   if (!obj->IsJSObject()) return false;
 
   Handle<String> error_key =
       factory()->InternalizeOneByteString(STATIC_ASCII_VECTOR("$Error"));
   Handle<Object> error_constructor = Object::GetProperty(
       js_builtins_object(), error_key).ToHandleChecked();
 
   DisallowHeapAllocation no_gc;
-  for (Object* prototype = *obj; !prototype->IsNull();
-       prototype = prototype->GetPrototype(this)) {
-    if (!prototype->IsJSObject()) return false;
-    if (JSObject::cast(prototype)->map()->constructor() ==
+  for (PrototypeIterator iter(this, *obj, PrototypeIterator::START_AT_RECEIVER);
+       !iter.IsAtEnd(); iter.Advance()) {
+    if (iter.GetCurrent()->IsJSProxy()) return false;
+    if (JSObject::cast(iter.GetCurrent())->map()->constructor() ==
         *error_constructor) {
       return true;
     }
   }
   return false;
 }
 
 static int fatal_exception_depth = 0;
 
 void Isolate::DoThrow(Object* exception, MessageLocation* location) {
@@ skipping 1349 matching lines @@
   if (prev_ && prev_->Intercept(flag)) return true;
   // Then check whether this scope intercepts.
   if ((flag & intercept_mask_)) {
     intercepted_flags_ |= flag;
     return true;
   }
   return false;
 }
 
 } }  // namespace v8::internal