Atomic ops: sync with Chromium.

src/atomicops.h

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 33 matching lines @@
 // Although there are currently no compiler enforcement, you are encouraged
 // to use these.
 //
 
 #ifndef V8_ATOMICOPS_H_
 #define V8_ATOMICOPS_H_
 
 #include "../include/v8.h"
 #include "globals.h"
 
+#if defined(_WIN32) && defined(V8_HOST_ARCH_64_BIT)
+// 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 v8 {
 namespace internal {
 
 typedef int32_t Atomic32;
 #ifdef V8_HOST_ARCH_64_BIT
 // We need to be able to go between Atomic64 and AtomicWord implicitly.  This
 // means Atomic64 and AtomicWord should be the same type on 64-bit.
-#if defined(__ILP32__) || defined(__APPLE__)
-// MacOS is an exception to the implicit conversion rule above,
-// because it uses long for intptr_t.
+#if defined(__ILP32__)
 typedef int64_t Atomic64;
 #else
 typedef intptr_t Atomic64;
 #endif
 #endif
 
 // Use AtomicWord for a machine-sized pointer.  It will use the Atomic32 or
 // Atomic64 routines below, depending on your architecture.
-#if defined(__OpenBSD__) && defined(__i386__)
-typedef Atomic32 AtomicWord;
-#else
 typedef intptr_t AtomicWord;
-#endif
 
 // Atomically execute:
 //      result = *ptr;
 //      if (*ptr == old_value)
 //        *ptr = new_value;
 //      return result;
 //
 // I.e., replace "*ptr" with "new_value" if "*ptr" used to be "old_value".
 // Always return the old value of "*ptr"
 //
@@ skipping 61 matching lines @@
 Atomic64 Release_Load(volatile const Atomic64* ptr);
 #endif  // V8_HOST_ARCH_64_BIT
 
 } }  // namespace v8::internal
 
 // Include our platform specific implementation.
 #if defined(THREAD_SANITIZER)
 #include "atomicops_internals_tsan.h"
 #elif defined(_MSC_VER) && (V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64)
 #include "atomicops_internals_x86_msvc.h"
-#elif defined(__APPLE__) && (V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64)
-#include "atomicops_internals_x86_macosx.h"
-#elif defined(__GNUC__) && (V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64)
-#include "atomicops_internals_x86_gcc.h"
+#elif defined(__APPLE__)
+#include "atomicops_internals_mac.h"
 #elif defined(__GNUC__) && V8_HOST_ARCH_A64
 #include "atomicops_internals_a64_gcc.h"
 #elif defined(__GNUC__) && V8_HOST_ARCH_ARM
 #include "atomicops_internals_arm_gcc.h"
+#elif defined(__GNUC__) && (V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64)
+#include "atomicops_internals_x86_gcc.h"
 #elif defined(__GNUC__) && V8_HOST_ARCH_MIPS
 #include "atomicops_internals_mips_gcc.h"
 #else
 #error "Atomic operations are not supported on your platform"
 #endif
 
+// On some platforms we need additional declarations to make
+// AtomicWord compatible with our other Atomic* types.
+#if defined(__APPLE__) || defined(__OpenBSD__)
+#include "atomicops_internals_atomicword_compat.h"
+#endif
+
 #endif  // V8_ATOMICOPS_H_