[Atomics] code stubs for atomic operations

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 44 matching lines @@
 //-------------------------------------------------------------------
 
 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 AtomicsLoadJS(sta, index) {
-  CheckSharedIntegerTypedArray(sta);
-  index = ValidateIndex(index, %_TypedArrayGetLength(sta));
-  return %_AtomicsLoad(sta, index);
-}
-
 function AtomicsStoreJS(sta, index, value) {
   CheckSharedIntegerTypedArray(sta);
   index = ValidateIndex(index, %_TypedArrayGetLength(sta));
   value = TO_NUMBER(value);
   return %_AtomicsStore(sta, index, value);
 }
 
 function AtomicsAddJS(ia, index, value) {
   CheckSharedIntegerTypedArray(ia);
   index = ValidateIndex(index, %_TypedArrayGetLength(ia));
@@ skipping 73 matching lines @@
   index2 = ValidateIndex(index2, %_TypedArrayGetLength(ia));
   if (index1 < 0 || index1 >= %_TypedArrayGetLength(ia) ||
       index2 < 0 || index2 >= %_TypedArrayGetLength(ia)) {
     return UNDEFINED;
   }
   return %AtomicsFutexWakeOrRequeue(ia, index1, count, value, index2);
 }
 
 // -------------------------------------------------------------------
 
-function AtomicsConstructor() {}
+var Atomics = global.Atomics;
 
-var Atomics = new AtomicsConstructor();
-
-%InternalSetPrototype(Atomics, GlobalObject.prototype);
-%AddNamedProperty(global, "Atomics", Atomics, DONT_ENUM);
-%FunctionSetInstanceClassName(AtomicsConstructor, 'Atomics');
+// The Atomics global is defined by the bootstrapper.
 
 %AddNamedProperty(Atomics, toStringTagSymbol, "Atomics", READ_ONLY | DONT_ENUM);
 
 // These must match the values in src/futex-emulation.h
 utils.InstallConstants(Atomics, [
   "OK", 0,
   "NOTEQUAL", -1,
   "TIMEDOUT", -2,
 ]);
 
 utils.InstallFunctions(Atomics, DONT_ENUM, [
+  // TODO(binji): remove the rest of the (non futex) Atomics functions as they
+  // become builtins.
   "compareExchange", AtomicsCompareExchangeJS,
-  "load", AtomicsLoadJS,
   "store", AtomicsStoreJS,
   "add", AtomicsAddJS,
   "sub", AtomicsSubJS,
   "and", AtomicsAndJS,
   "or", AtomicsOrJS,
   "xor", AtomicsXorJS,
   "exchange", AtomicsExchangeJS,
   "isLockFree", AtomicsIsLockFreeJS,
   "futexWait", AtomicsFutexWaitJS,
   "futexWake", AtomicsFutexWakeJS,
   "futexWakeOrRequeue", AtomicsFutexWakeOrRequeueJS,
 ]);
 
 })