Workaround to make MemoryBarrier compile on Win x64

base/atomicops_internals_x86_msvc.h

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file is an internal atomic implementation, use base/atomicops.h instead.
 
 #ifndef BASE_ATOMICOPS_INTERNALS_X86_MSVC_H_
 #define BASE_ATOMICOPS_INTERNALS_X86_MSVC_H_
 
 #include <windows.h>
 
+#if defined(ARCH_CPU_64_BITS)
+// windows.h #defines this (only on x64). This causes problems because the
+// public API also uses MemoryBarrier at the public name for this fence. So, on
+// X64, undef it, and call its documented
+// (http://msdn.microsoft.com/en-us/library/windows/desktop/ms684208.aspx)
+// implementation directly.
+#undef MemoryBarrier
+#endif
+
 namespace base {
 namespace subtle {
 
 inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr,
                                          Atomic32 old_value,
                                          Atomic32 new_value) {
   LONG result = InterlockedCompareExchange(
       reinterpret_cast<volatile LONG*>(ptr),
       static_cast<LONG>(new_value),
       static_cast<LONG>(old_value));
@@ skipping 17 matching lines @@
 
 inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr,
                                           Atomic32 increment) {
   return Barrier_AtomicIncrement(ptr, increment);
 }
 
 #if !(defined(_MSC_VER) && _MSC_VER >= 1400)
 #error "We require at least vs2005 for MemoryBarrier"
 #endif
 inline void MemoryBarrier() {
+#if defined(ARCH_CPU_64_BITS)
+  // See #undef and note at the top of this file.
+  __faststorefence();
+#else
   // We use MemoryBarrier from WinNT.h
   ::MemoryBarrier();
+#endif
 }
 
 inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr,
                                        Atomic32 old_value,
                                        Atomic32 new_value) {
   return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
 }
 
 inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
                                        Atomic32 old_value,
@@ skipping 110 matching lines @@
   return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
 }
 
 
 #endif  // defined(_WIN64)
 
 }  // namespace base::subtle
 }  // namespace base
 
 #endif  // BASE_ATOMICOPS_INTERNALS_X86_MSVC_H_