Do not use js builtins object to determine whether a function is a builtin.

src/objects-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.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 5519 matching lines @@
 ACCESSORS(Script, source_mapping_url, Object, kSourceMappingUrlOffset)
 
 Script::CompilationType Script::compilation_type() {
   return BooleanBit::get(flags(), kCompilationTypeBit) ?
       COMPILATION_TYPE_EVAL : COMPILATION_TYPE_HOST;
 }
 void Script::set_compilation_type(CompilationType type) {
   set_flags(BooleanBit::set(flags(), kCompilationTypeBit,
       type == COMPILATION_TYPE_EVAL));
 }
+bool Script::hide_source() { return BooleanBit::get(flags(), kHideSourceBit); }
+void Script::set_hide_source(bool value) {
+  set_flags(BooleanBit::set(flags(), kHideSourceBit, value));
+}
 Script::CompilationState Script::compilation_state() {
   return BooleanBit::get(flags(), kCompilationStateBit) ?
       COMPILATION_STATE_COMPILED : COMPILATION_STATE_INITIAL;
 }
 void Script::set_compilation_state(CompilationState state) {
   set_flags(BooleanBit::set(flags(), kCompilationStateBit,
       state == COMPILATION_STATE_COMPILED));
 }
 ScriptOriginOptions Script::origin_options() {
   return ScriptOriginOptions((flags()->value() & kOriginOptionsMask) >>
@@ skipping 445 matching lines @@
   }
 }
 
 
 void SharedFunctionInfo::set_disable_optimization_reason(BailoutReason reason) {
   set_opt_count_and_bailout_reason(DisabledOptimizationReasonBits::update(
       opt_count_and_bailout_reason(), reason));
 }
 
 
-bool SharedFunctionInfo::IsSubjectToDebugging() {
+bool SharedFunctionInfo::IsBuiltin() {
   Object* script_obj = script();
-  if (script_obj->IsUndefined()) return false;
+  if (script_obj->IsUndefined()) return true;
   Script* script = Script::cast(script_obj);
   Script::Type type = static_cast<Script::Type>(script->type()->value());
-  return type == Script::TYPE_NORMAL;
+  return type != Script::TYPE_NORMAL;
 }
 
 
-bool JSFunction::IsBuiltin() {
-  return context()->global_object()->IsJSBuiltinsObject();
-}
+bool SharedFunctionInfo::IsSubjectToDebugging() { return !IsBuiltin(); }
+
+
+bool JSFunction::IsBuiltin() { return shared()->IsBuiltin(); }
 
 
 bool JSFunction::IsSubjectToDebugging() {
   return shared()->IsSubjectToDebugging();
 }
 
 
 bool JSFunction::NeedsArgumentsAdaption() {
   return shared()->internal_formal_parameter_count() !=
          SharedFunctionInfo::kDontAdaptArgumentsSentinel;
@@ skipping 1800 matching lines @@
 #undef READ_INT64_FIELD
 #undef WRITE_INT64_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_