Use SameValueZero for Map and Set

src/collection.js

 // 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.
 
 "use strict";
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $Array = global.Array;
 
 var $Set = global.Set;
 var $Map = global.Map;
 
-// Global sentinel to be used instead of undefined keys, which are not
-// supported internally but required for Harmony sets and maps.
-var undefined_sentinel = {};
-
-
-// Map and Set uses SameValueZero which means that +0 and -0 should be treated
-// as the same value.
-function NormalizeKey(key) {
-  if (IS_UNDEFINED(key)) {
-    return undefined_sentinel;
-  }
-
-  if (key === 0) {
-    return 0;
-  }
-
-  return key;
-}
-
 
 // -------------------------------------------------------------------
 // Harmony Set
 
 function SetConstructor() {
   if (%_IsConstructCall()) {
     %SetInitialize(this);
   } else {
     throw MakeTypeError('constructor_not_function', ['Set']);
   }
 }
 
 
 function SetAddJS(key) {
   if (!IS_SET(this)) {
     throw MakeTypeError('incompatible_method_receiver',
                         ['Set.prototype.add', this]);
   }
-  return %SetAdd(this, NormalizeKey(key));
+  return %SetAdd(this, key);
 }
 
 
 function SetHasJS(key) {
   if (!IS_SET(this)) {
     throw MakeTypeError('incompatible_method_receiver',
                         ['Set.prototype.has', this]);
   }
-  return %SetHas(this, NormalizeKey(key));
+  return %SetHas(this, key);
 }
 
 
 function SetDeleteJS(key) {
   if (!IS_SET(this)) {
     throw MakeTypeError('incompatible_method_receiver',
                         ['Set.prototype.delete', this]);
   }
-  key = NormalizeKey(key);
   if (%SetHas(this, key)) {
     %SetDelete(this, key);
     return true;
   } else {
     return false;
   }
 }
 
 
 function SetGetSizeJS() {
@@ skipping 67 matching lines @@
     throw MakeTypeError('constructor_not_function', ['Map']);
   }
 }
 
 
 function MapGetJS(key) {
   if (!IS_MAP(this)) {
     throw MakeTypeError('incompatible_method_receiver',
                         ['Map.prototype.get', this]);
   }
-  return %MapGet(this, NormalizeKey(key));
+  return %MapGet(this, key);
 }
 
 
 function MapSetJS(key, value) {
   if (!IS_MAP(this)) {
     throw MakeTypeError('incompatible_method_receiver',
                         ['Map.prototype.set', this]);
   }
-  return %MapSet(this, NormalizeKey(key), value);
+  return %MapSet(this, key, value);
 }
 
 
 function MapHasJS(key) {
   if (!IS_MAP(this)) {
     throw MakeTypeError('incompatible_method_receiver',
                         ['Map.prototype.has', this]);
   }
-  return %MapHas(this, NormalizeKey(key));
+  return %MapHas(this, key);
 }
 
 
 function MapDeleteJS(key) {
   if (!IS_MAP(this)) {
     throw MakeTypeError('incompatible_method_receiver',
                         ['Map.prototype.delete', this]);
   }
-  return %MapDelete(this, NormalizeKey(key));
+  return %MapDelete(this, key);
 }
 
 
 function MapGetSizeJS() {
   if (!IS_MAP(this)) {
     throw MakeTypeError('incompatible_method_receiver',
                         ['Map.prototype.size', this]);
   }
   return %MapGetSize(this);
 }
@@ skipping 43 matching lines @@
     "get", MapGetJS,
     "set", MapSetJS,
     "has", MapHasJS,
     "delete", MapDeleteJS,
     "clear", MapClearJS,
     "forEach", MapForEach
   ));
 }
 
 SetUpMap();