Reland Update implementation of atomics with latest Chromium version but use compiler builtin atomi…

src/base/atomicops_internals_mac.h

-// 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_