- Add AtomicOperations::CompareAndSwapWord

runtime/vm/atomic_macos.h

Index: runtime/vm/atomic_macos.h
===================================================================
--- runtime/vm/atomic_macos.h	(working copy)
+++ runtime/vm/atomic_macos.h	(working copy)
@@ -2,19 +2,31 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-#include "platform/globals.h"
-#if defined(TARGET_OS_MACOS)
+#ifndef VM_ATOMIC_MACOS_H_
+#define VM_ATOMIC_MACOS_H_
 
-#include "vm/atomic.h"
+#if !defined VM_ATOMIC_H_
+#error Do not include atomic_macos.h directly. Use atomic.h instead.
+#endif
 
+#if !defined(TARGET_OS_MACOS)
+#error This file should only be included on Mac OS X builds.
+#endif
+
 namespace dart {
 
 
-uintptr_t AtomicOperations::FetchAndIncrement(uintptr_t* p) {
+inline uintptr_t AtomicOperations::FetchAndIncrement(uintptr_t* p) {
   return __sync_fetch_and_add(p, 1);
 }
 
 
+inline uword AtomicOperations::CompareAndSwapWord(uword* ptr,
+                                                  uword old_value,
+                                                  uword new_value) {
+  return __sync_val_compare_and_swap(ptr, old_value, new_value);
+}
+
 }  // namespace dart
 
-#endif  // defined(TARGET_OS_MACOS)
+#endif  // VM_ATOMIC_MACOS_H_