diff options
Diffstat (limited to 'security/sandbox/chromium/base/atomicops_internals_portable.h')
| -rw-r--r-- | security/sandbox/chromium/base/atomicops_internals_portable.h | 229 |
1 files changed, 0 insertions, 229 deletions
diff --git a/security/sandbox/chromium/base/atomicops_internals_portable.h b/security/sandbox/chromium/base/atomicops_internals_portable.h deleted file mode 100644 index ee034dee1..000000000 --- a/security/sandbox/chromium/base/atomicops_internals_portable.h +++ /dev/null @@ -1,229 +0,0 @@ -// Copyright (c) 2014 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 atomicops.h instead. -// -// This implementation uses C++11 atomics' member functions. The code base is -// currently written assuming atomicity revolves around accesses instead of -// C++11's memory locations. The burden is on the programmer to ensure that all -// memory locations accessed atomically are never accessed non-atomically (tsan -// should help with this). -// -// TODO(jfb) Modify the atomicops.h API and user code to declare atomic -// locations as truly atomic. See the static_assert below. -// -// Of note in this implementation: -// * All NoBarrier variants are implemented as relaxed. -// * All Barrier variants are implemented as sequentially-consistent. -// * Compare exchange's failure ordering is always the same as the success one -// (except for release, which fails as relaxed): using a weaker ordering is -// only valid under certain uses of compare exchange. -// * Acquire store doesn't exist in the C11 memory model, it is instead -// implemented as a relaxed store followed by a sequentially consistent -// fence. -// * Release load doesn't exist in the C11 memory model, it is instead -// implemented as sequentially consistent fence followed by a relaxed load. -// * Atomic increment is expected to return the post-incremented value, whereas -// C11 fetch add returns the previous value. The implementation therefore -// needs to increment twice (which the compiler should be able to detect and -// optimize). - -#ifndef BASE_ATOMICOPS_INTERNALS_PORTABLE_H_ -#define BASE_ATOMICOPS_INTERNALS_PORTABLE_H_ - -#include <atomic> - -#include "build/build_config.h" - -namespace base { -namespace subtle { - -// This implementation is transitional and maintains the original API for -// atomicops.h. This requires casting memory locations to the atomic types, and -// assumes that the API and the C++11 implementation are layout-compatible, -// which isn't true for all implementations or hardware platforms. The static -// assertion should detect this issue, were it to fire then this header -// shouldn't be used. -// -// TODO(jfb) If this header manages to stay committed then the API should be -// modified, and all call sites updated. -typedef volatile std::atomic<Atomic32>* AtomicLocation32; -static_assert(sizeof(*(AtomicLocation32) nullptr) == sizeof(Atomic32), - "incompatible 32-bit atomic layout"); - -inline void MemoryBarrier() { -#if defined(__GLIBCXX__) - // Work around libstdc++ bug 51038 where atomic_thread_fence was declared but - // not defined, leading to the linker complaining about undefined references. - __atomic_thread_fence(std::memory_order_seq_cst); -#else - std::atomic_thread_fence(std::memory_order_seq_cst); -#endif -} - -inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr, - Atomic32 old_value, - Atomic32 new_value) { - ((AtomicLocation32)ptr) - ->compare_exchange_strong(old_value, - new_value, - std::memory_order_relaxed, - std::memory_order_relaxed); - return old_value; -} - -inline Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr, - Atomic32 new_value) { - return ((AtomicLocation32)ptr) - ->exchange(new_value, std::memory_order_relaxed); -} - -inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr, - Atomic32 increment) { - return increment + - ((AtomicLocation32)ptr) - ->fetch_add(increment, std::memory_order_relaxed); -} - -inline Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr, - Atomic32 increment) { - return increment + ((AtomicLocation32)ptr)->fetch_add(increment); -} - -inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr, - Atomic32 old_value, - Atomic32 new_value) { - ((AtomicLocation32)ptr) - ->compare_exchange_strong(old_value, - new_value, - std::memory_order_acquire, - std::memory_order_acquire); - return old_value; -} - -inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr, - Atomic32 old_value, - Atomic32 new_value) { - ((AtomicLocation32)ptr) - ->compare_exchange_strong(old_value, - new_value, - std::memory_order_release, - std::memory_order_relaxed); - return old_value; -} - -inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) { - ((AtomicLocation32)ptr)->store(value, std::memory_order_relaxed); -} - -inline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) { - ((AtomicLocation32)ptr)->store(value, std::memory_order_relaxed); - MemoryBarrier(); -} - -inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) { - ((AtomicLocation32)ptr)->store(value, std::memory_order_release); -} - -inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) { - return ((AtomicLocation32)ptr)->load(std::memory_order_relaxed); -} - -inline Atomic32 Acquire_Load(volatile const Atomic32* ptr) { - return ((AtomicLocation32)ptr)->load(std::memory_order_acquire); -} - -inline Atomic32 Release_Load(volatile const Atomic32* ptr) { - MemoryBarrier(); - return ((AtomicLocation32)ptr)->load(std::memory_order_relaxed); -} - -#if defined(ARCH_CPU_64_BITS) - -typedef volatile std::atomic<Atomic64>* AtomicLocation64; -static_assert(sizeof(*(AtomicLocation64) nullptr) == sizeof(Atomic64), - "incompatible 64-bit atomic layout"); - -inline Atomic64 NoBarrier_CompareAndSwap(volatile Atomic64* ptr, - Atomic64 old_value, - Atomic64 new_value) { - ((AtomicLocation64)ptr) - ->compare_exchange_strong(old_value, - new_value, - std::memory_order_relaxed, - std::memory_order_relaxed); - return old_value; -} - -inline Atomic64 NoBarrier_AtomicExchange(volatile Atomic64* ptr, - Atomic64 new_value) { - return ((AtomicLocation64)ptr) - ->exchange(new_value, std::memory_order_relaxed); -} - -inline Atomic64 NoBarrier_AtomicIncrement(volatile Atomic64* ptr, - Atomic64 increment) { - return increment + - ((AtomicLocation64)ptr) - ->fetch_add(increment, std::memory_order_relaxed); -} - -inline Atomic64 Barrier_AtomicIncrement(volatile Atomic64* ptr, - Atomic64 increment) { - return increment + ((AtomicLocation64)ptr)->fetch_add(increment); -} - -inline Atomic64 Acquire_CompareAndSwap(volatile Atomic64* ptr, - Atomic64 old_value, - Atomic64 new_value) { - ((AtomicLocation64)ptr) - ->compare_exchange_strong(old_value, - new_value, - std::memory_order_acquire, - std::memory_order_acquire); - return old_value; -} - -inline Atomic64 Release_CompareAndSwap(volatile Atomic64* ptr, - Atomic64 old_value, - Atomic64 new_value) { - ((AtomicLocation64)ptr) - ->compare_exchange_strong(old_value, - new_value, - std::memory_order_release, - std::memory_order_relaxed); - return old_value; -} - -inline void NoBarrier_Store(volatile Atomic64* ptr, Atomic64 value) { - ((AtomicLocation64)ptr)->store(value, std::memory_order_relaxed); -} - -inline void Acquire_Store(volatile Atomic64* ptr, Atomic64 value) { - ((AtomicLocation64)ptr)->store(value, std::memory_order_relaxed); - MemoryBarrier(); -} - -inline void Release_Store(volatile Atomic64* ptr, Atomic64 value) { - ((AtomicLocation64)ptr)->store(value, std::memory_order_release); -} - -inline Atomic64 NoBarrier_Load(volatile const Atomic64* ptr) { - return ((AtomicLocation64)ptr)->load(std::memory_order_relaxed); -} - -inline Atomic64 Acquire_Load(volatile const Atomic64* ptr) { - return ((AtomicLocation64)ptr)->load(std::memory_order_acquire); -} - -inline Atomic64 Release_Load(volatile const Atomic64* ptr) { - MemoryBarrier(); - return ((AtomicLocation64)ptr)->load(std::memory_order_relaxed); -} - -#endif // defined(ARCH_CPU_64_BITS) -} // namespace subtle -} // namespace base - -#endif // BASE_ATOMICOPS_INTERNALS_PORTABLE_H_ |