Atomic ops: sync with Chromium.

src/atomicops.h

Index: src/atomicops.h
diff --git a/src/atomicops.h b/src/atomicops.h
index d7d4df6763f791d54caa996627a69f49a591eb36..aa2b22f141aa738d5e342d76c808c72cb25881ca 100644
--- a/src/atomicops.h
+++ b/src/atomicops.h
@@ -51,6 +51,15 @@
 #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 {
 
@@ -58,9 +67,7 @@ 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;
@@ -69,11 +76,7 @@ typedef intptr_t Atomic64;
 
 // 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;
@@ -155,18 +158,24 @@ Atomic64 Release_Load(volatile const Atomic64* ptr);
 #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_