Fix cached EnumLength retrieval in JSObject::NumberOfOwnProperties

src/objects.cc

 // Copyright 2013 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 14773 matching lines @@
   Maybe<PropertyAttributes> maybe_result = GetPropertyAttributes(&it);
   return maybe_result.IsJust() ? Just(it.state() == LookupIterator::ACCESSOR)
                                : Nothing<bool>();
 }
 
 
 int JSObject::NumberOfOwnProperties(PropertyAttributes filter) {
   if (HasFastProperties()) {
     Map* map = this->map();
     if (filter == NONE) return map->NumberOfOwnDescriptors();
-    if (filter & DONT_ENUM) {
+    if (filter == DONT_SHOW) {
+      // The cached enum length was computed with filter == DONT_SHOW, so
+      // that's the only filter for which it's valid to retrieve it.
       int result = map->EnumLength();
       if (result != kInvalidEnumCacheSentinel) return result;
     }
     return map->NumberOfDescribedProperties(OWN_DESCRIPTORS, filter);
   } else if (IsGlobalObject()) {
     return global_dictionary()->NumberOfElementsFilterAttributes(filter);
   } else {
     return property_dictionary()->NumberOfElementsFilterAttributes(filter);
   }
 }
@@ skipping 3128 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