Make all global private symbols own symbols.

src/array-iterator.js

 // 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.
 
 'use strict';
 
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $Array = global.Array;
 
 
-var arrayIteratorObjectSymbol = GLOBAL_PRIVATE("ArrayIterator#object");
-var arrayIteratorNextIndexSymbol = GLOBAL_PRIVATE("ArrayIterator#next");
-var arrayIterationKindSymbol = GLOBAL_PRIVATE("ArrayIterator#kind");
+var arrayIteratorObjectSymbol = GLOBAL_PRIVATE_OWN("ArrayIterator#object");
+var arrayIteratorNextIndexSymbol = GLOBAL_PRIVATE_OWN("ArrayIterator#next");
+var arrayIterationKindSymbol = GLOBAL_PRIVATE_OWN("ArrayIterator#kind");
+
+var arrayEndOfIterationMarker = new $Object();
 
 
 function ArrayIterator() {}
 
 
 // TODO(wingo): Update section numbers when ES6 has stabilized.  The
 // section numbers below are already out of date as of the May 2014
 // draft.
 
 
@@ skipping 17 matching lines @@
 // 22.1.5.2.2 %ArrayIteratorPrototype%[@@iterator]
 function ArrayIteratorIterator() {
     return this;
 }
 
 
 // 15.4.5.2.2 ArrayIterator.prototype.next( )
 function ArrayIteratorNext() {
   var iterator = ToObject(this);
 
-  if (!HAS_PRIVATE(iterator, arrayIteratorObjectSymbol)) {
+  if (IS_PRIVATE_OWN_UNDEFINED(iterator, arrayIteratorObjectSymbol)) {
     throw MakeTypeError('incompatible_method_receiver',
                         ['Array Iterator.prototype.next']);
   }
 
   var array = GET_PRIVATE(iterator, arrayIteratorObjectSymbol);
-  if (IS_UNDEFINED(array)) {
+  if (array === arrayEndOfIterationMarker) {
     return CreateIteratorResultObject(UNDEFINED, true);
   }
 
   var index = GET_PRIVATE(iterator, arrayIteratorNextIndexSymbol);
   var itemKind = GET_PRIVATE(iterator, arrayIterationKindSymbol);
   var length = TO_UINT32(array.length);
 
   // "sparse" is never used.
 
   if (index >= length) {
-    SET_PRIVATE(iterator, arrayIteratorObjectSymbol, UNDEFINED);
+    SET_PRIVATE(iterator, arrayIteratorObjectSymbol, arrayEndOfIterationMarker);
     return CreateIteratorResultObject(UNDEFINED, true);
   }
 
   SET_PRIVATE(iterator, arrayIteratorNextIndexSymbol, index + 1);
 
   if (itemKind == ITERATOR_KIND_VALUES) {
     return CreateIteratorResultObject(array[index], false);
   }
 
   if (itemKind == ITERATOR_KIND_ENTRIES) {
@@ skipping 67 matching lines @@
 macro EXTEND_TYPED_ARRAY(NAME)
   %AddNamedProperty($NAME.prototype, 'entries', ArrayEntries, DONT_ENUM);
   %AddNamedProperty($NAME.prototype, 'values', ArrayValues, DONT_ENUM);
   %AddNamedProperty($NAME.prototype, 'keys', ArrayKeys, DONT_ENUM);
   %AddNamedProperty($NAME.prototype, symbolIterator, ArrayValues, DONT_ENUM);
 endmacro
 
   TYPED_ARRAYS(EXTEND_TYPED_ARRAY)
 }
 ExtendTypedArrayPrototypes();