Add fast path for array indices to Runtime_HasOwnProperty

src/runtime/runtime-object.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/arguments.h"
 #include "src/bootstrapper.h"
 #include "src/debug.h"
 #include "src/runtime/runtime.h"
@@ skipping 797 matching lines @@
 
   uint32_t index;
   const bool key_is_array_index = key->AsArrayIndex(&index);
 
   // Only JS objects can have properties.
   if (object->IsJSObject()) {
     Handle<JSObject> js_obj = Handle<JSObject>::cast(object);
     // Fast case: either the key is a real named property or it is not
     // an array index and there are no interceptors or hidden
     // prototypes.
-    Maybe<bool> maybe = JSObject::HasRealNamedProperty(js_obj, key);
+    Maybe<bool> maybe;
+    if (key_is_array_index) {
+      maybe = JSObject::HasOwnElement(js_obj, index);
+    } else {
+      maybe = JSObject::HasRealNamedProperty(js_obj, key);
+    }
     if (!maybe.has_value) return isolate->heap()->exception();
     DCHECK(!isolate->has_pending_exception());
     if (maybe.value) {
       return isolate->heap()->true_value();
     }
     Map* map = js_obj->map();
     if (!key_is_array_index && !map->has_named_interceptor() &&
         !HeapObject::cast(map->prototype())->map()->is_hidden_prototype()) {
       return isolate->heap()->false_value();
     }
@@ skipping 771 matching lines @@
 
 RUNTIME_FUNCTION(RuntimeReference_ClassOf) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_CHECKED(Object, obj, 0);
   if (!obj->IsJSReceiver()) return isolate->heap()->null_value();
   return JSReceiver::cast(obj)->class_name();
 }
 }
 }  // namespace v8::internal