Revert of Update implementation of atomics with latest Chromium version but use compiler builtin atomics

src/base/atomicops_internals_mac.h

Index: src/base/atomicops_internals_mac.h
diff --git a/src/base/atomicops_internals_mac.h b/src/base/atomicops_internals_mac.h
new file mode 100644
index 0000000000000000000000000000000000000000..c112506238adc6eea5a6ed3813a09408b6e06e68
--- /dev/null
+++ b/src/base/atomicops_internals_mac.h
@@ -0,0 +1,216 @@
+// Copyright 2010 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.
+
+// This file is an internal atomic implementation, use atomicops.h instead.
+
+#ifndef V8_BASE_ATOMICOPS_INTERNALS_MAC_H_
+#define V8_BASE_ATOMICOPS_INTERNALS_MAC_H_
+
+#include <libkern/OSAtomic.h>
+
+namespace v8 {
+namespace base {
+
+#define ATOMICOPS_COMPILER_BARRIER() __asm__ __volatile__("" : : : "memory")
+
+inline void MemoryBarrier() { OSMemoryBarrier(); }
+
+inline void AcquireMemoryBarrier() {
+// On x86 processors, loads already have acquire semantics, so
+// there is no need to put a full barrier here.
+#if V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64
+  ATOMICOPS_COMPILER_BARRIER();
+#else
+  MemoryBarrier();
+#endif
+}
+
+inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr,
+                                         Atomic32 old_value,
+                                         Atomic32 new_value) {
+  Atomic32 prev_value;
+  do {
+    if (OSAtomicCompareAndSwap32(old_value, new_value,
+                                 const_cast<Atomic32*>(ptr))) {
+      return old_value;
+    }
+    prev_value = *ptr;
+  } while (prev_value == old_value);
+  return prev_value;
+}
+
+inline Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr,
+                                         Atomic32 new_value) {
+  Atomic32 old_value;
+  do {
+    old_value = *ptr;
+  } while (!OSAtomicCompareAndSwap32(old_value, new_value,
+                                     const_cast<Atomic32*>(ptr)));
+  return old_value;
+}
+
+inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr,
+                                          Atomic32 increment) {
+  return OSAtomicAdd32(increment, const_cast<Atomic32*>(ptr));
+}
+
+inline Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr,
+                                        Atomic32 increment) {
+  return OSAtomicAdd32Barrier(increment, const_cast<Atomic32*>(ptr));
+}
+
+inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr,
+                                       Atomic32 old_value,
+                                       Atomic32 new_value) {
+  Atomic32 prev_value;
+  do {
+    if (OSAtomicCompareAndSwap32Barrier(old_value, new_value,
+                                        const_cast<Atomic32*>(ptr))) {
+      return old_value;
+    }
+    prev_value = *ptr;
+  } while (prev_value == old_value);
+  return prev_value;
+}
+
+inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
+                                       Atomic32 old_value,
+                                       Atomic32 new_value) {
+  return Acquire_CompareAndSwap(ptr, old_value, new_value);
+}
+
+inline void NoBarrier_Store(volatile Atomic8* ptr, Atomic8 value) {
+  *ptr = value;
+}
+
+inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) {
+  *ptr = value;
+}
+
+inline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) {
+  *ptr = value;
+  MemoryBarrier();
+}
+
+inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) {
+  MemoryBarrier();
+  *ptr = value;
+}
+
+inline Atomic8 NoBarrier_Load(volatile const Atomic8* ptr) {
+  return *ptr;
+}
+
+inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) {
+  return *ptr;
+}
+
+inline Atomic32 Acquire_Load(volatile const Atomic32* ptr) {
+  Atomic32 value = *ptr;
+  AcquireMemoryBarrier();
+  return value;
+}
+
+inline Atomic32 Release_Load(volatile const Atomic32* ptr) {
+  MemoryBarrier();
+  return *ptr;
+}
+
+#ifdef __LP64__
+
+// 64-bit implementation on 64-bit platform
+
+inline Atomic64 NoBarrier_CompareAndSwap(volatile Atomic64* ptr,
+                                         Atomic64 old_value,
+                                         Atomic64 new_value) {
+  Atomic64 prev_value;
+  do {
+    if (OSAtomicCompareAndSwap64(old_value, new_value,
+                                 reinterpret_cast<volatile int64_t*>(ptr))) {
+      return old_value;
+    }
+    prev_value = *ptr;
+  } while (prev_value == old_value);
+  return prev_value;
+}
+
+inline Atomic64 NoBarrier_AtomicExchange(volatile Atomic64* ptr,
+                                         Atomic64 new_value) {
+  Atomic64 old_value;
+  do {
+    old_value = *ptr;
+  } while (!OSAtomicCompareAndSwap64(old_value, new_value,
+                                     reinterpret_cast<volatile int64_t*>(ptr)));
+  return old_value;
+}
+
+inline Atomic64 NoBarrier_AtomicIncrement(volatile Atomic64* ptr,
+                                          Atomic64 increment) {
+  return OSAtomicAdd64(increment, reinterpret_cast<volatile int64_t*>(ptr));
+}
+
+inline Atomic64 Barrier_AtomicIncrement(volatile Atomic64* ptr,
+                                        Atomic64 increment) {
+  return OSAtomicAdd64Barrier(increment,
+                              reinterpret_cast<volatile int64_t*>(ptr));
+}
+
+inline Atomic64 Acquire_CompareAndSwap(volatile Atomic64* ptr,
+                                       Atomic64 old_value,
+                                       Atomic64 new_value) {
+  Atomic64 prev_value;
+  do {
+    if (OSAtomicCompareAndSwap64Barrier(
+        old_value, new_value, reinterpret_cast<volatile int64_t*>(ptr))) {
+      return old_value;
+    }
+    prev_value = *ptr;
+  } while (prev_value == old_value);
+  return prev_value;
+}
+
+inline Atomic64 Release_CompareAndSwap(volatile Atomic64* ptr,
+                                       Atomic64 old_value,
+                                       Atomic64 new_value) {
+  // The lib kern interface does not distinguish between
+  // Acquire and Release memory barriers; they are equivalent.
+  return Acquire_CompareAndSwap(ptr, old_value, new_value);
+}
+
+inline void NoBarrier_Store(volatile Atomic64* ptr, Atomic64 value) {
+  *ptr = value;
+}
+
+inline void Acquire_Store(volatile Atomic64* ptr, Atomic64 value) {
+  *ptr = value;
+  MemoryBarrier();
+}
+
+inline void Release_Store(volatile Atomic64* ptr, Atomic64 value) {
+  MemoryBarrier();
+  *ptr = value;
+}
+
+inline Atomic64 NoBarrier_Load(volatile const Atomic64* ptr) {
+  return *ptr;
+}
+
+inline Atomic64 Acquire_Load(volatile const Atomic64* ptr) {
+  Atomic64 value = *ptr;
+  AcquireMemoryBarrier();
+  return value;
+}
+
+inline Atomic64 Release_Load(volatile const Atomic64* ptr) {
+  MemoryBarrier();
+  return *ptr;
+}
+
+#endif  // defined(__LP64__)
+
+#undef ATOMICOPS_COMPILER_BARRIER
+}  // namespace base
+}  // namespace v8
+
+#endif  // V8_BASE_ATOMICOPS_INTERNALS_MAC_H_