[Atomics] Make Atomics.compareExchange a builtin using TF

src/js/harmony-atomics.js

 // 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.
 
 (function(global, utils) {
 
 "use strict";
 
 %CheckIsBootstrapping();
 
@@ skipping 34 matching lines @@
     throw %make_range_error(kInvalidAtomicAccessIndex);
   }
   if (accessIndex < 0 || accessIndex >= length) {
     throw %make_range_error(kInvalidAtomicAccessIndex);
   }
   return accessIndex;
 }
 
 //-------------------------------------------------------------------
 
-function AtomicsCompareExchangeJS(sta, index, oldValue, newValue) {
-  CheckSharedIntegerTypedArray(sta);
-  index = ValidateIndex(index, %_TypedArrayGetLength(sta));
-  oldValue = TO_NUMBER(oldValue);
-  newValue = TO_NUMBER(newValue);
-  return %_AtomicsCompareExchange(sta, index, oldValue, newValue);
-}
-
 function AtomicsAddJS(ia, index, value) {
   CheckSharedIntegerTypedArray(ia);
   index = ValidateIndex(index, %_TypedArrayGetLength(ia));
   value = TO_NUMBER(value);
   return %_AtomicsAdd(ia, index, value);
 }
 
 function AtomicsSubJS(ia, index, value) {
   CheckSharedIntegerTypedArray(ia);
   index = ValidateIndex(index, %_TypedArrayGetLength(ia));
@@ skipping 58 matching lines @@
 
 var Atomics = global.Atomics;
 
 // The Atomics global is defined by the bootstrapper.
 
 %AddNamedProperty(Atomics, toStringTagSymbol, "Atomics", READ_ONLY | DONT_ENUM);
 
 utils.InstallFunctions(Atomics, DONT_ENUM, [
   // TODO(binji): remove the rest of the (non futex) Atomics functions as they
   // become builtins.
-  "compareExchange", AtomicsCompareExchangeJS,
   "add", AtomicsAddJS,
   "sub", AtomicsSubJS,
   "and", AtomicsAndJS,
   "or", AtomicsOrJS,
   "xor", AtomicsXorJS,
   "isLockFree", AtomicsIsLockFreeJS,
   "wait", AtomicsWaitJS,
   "wake", AtomicsWakeJS,
 ]);
 
 })