Speed up the LookupIterator

src/objects.cc

 // Copyright 2015 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/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <sstream>
 
@@ skipping 8422 matching lines @@
     Handle<FixedArray> array, int length) {
   DCHECK_LE(length, array->length());
   if (array->length() == length) return array;
   return array->GetIsolate()->factory()->CopyFixedArrayUpTo(array, length);
 }
 
 bool Map::OnlyHasSimpleProperties() {
   // Wrapped string elements aren't explicitly stored in the elements backing
   // store, but are loaded indirectly from the underlying string.
   return !IsStringWrapperElementsKind(elements_kind()) &&
-         !is_access_check_needed() && !has_named_interceptor() &&
-         !has_indexed_interceptor() && !has_hidden_prototype() &&
-         !is_dictionary_map();
+         instance_type() > LAST_SPECIAL_RECEIVER_TYPE &&
+         !has_hidden_prototype() && !is_dictionary_map();
 }
 
 namespace {
 
 Handle<FixedArray> GetFastEnumPropertyKeys(Isolate* isolate,
                                            Handle<JSObject> object) {
   Handle<Map> map(object->map());
   bool cache_enum_length = map->OnlyHasSimpleProperties();
 
   Handle<DescriptorArray> descs =
@@ skipping 11402 matching lines @@
   if (cell->value() != *new_value) {
     cell->set_value(*new_value);
     Isolate* isolate = cell->GetIsolate();
     cell->dependent_code()->DeoptimizeDependentCodeGroup(
         isolate, DependentCode::kPropertyCellChangedGroup);
   }
 }
 
 }  // namespace internal
 }  // namespace v8