| // Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| #ifndef RUNTIME_PLATFORM_ATOMIC_H_ |
| #define RUNTIME_PLATFORM_ATOMIC_H_ |
| |
| #include <atomic> |
| |
| #include "platform/allocation.h" |
| #include "platform/globals.h" |
| |
| namespace dart { |
| |
| // Like std::atomic, but operations default to relaxed ordering instead of |
| // acquire-release ordering. |
| template <typename T> |
| class RelaxedAtomic { |
| public: |
| constexpr RelaxedAtomic() : value_() {} |
| constexpr RelaxedAtomic(T arg) : value_(arg) {} // NOLINT |
| RelaxedAtomic(const RelaxedAtomic& arg) : value_(arg) {} // NOLINT |
| |
| T load() const { return value_.load(std::memory_order_relaxed); } |
| void store(T arg) { value_.store(arg, std::memory_order_relaxed); } |
| |
| T fetch_add(T arg) { |
| return value_.fetch_add(arg, std::memory_order_relaxed); |
| } |
| T fetch_sub(T arg) { |
| return value_.fetch_sub(arg, std::memory_order_relaxed); |
| } |
| T fetch_or(T arg) { return value_.fetch_or(arg, std::memory_order_relaxed); } |
| T fetch_and(T arg) { |
| return value_.fetch_and(arg, std::memory_order_relaxed); |
| } |
| |
| bool compare_exchange_weak(T& expected, T desired) { // NOLINT |
| return value_.compare_exchange_weak(expected, desired, |
| std::memory_order_relaxed, |
| std::memory_order_relaxed); |
| } |
| bool compare_exchange_strong(T& expected, T desired) { // NOLINT |
| return value_.compare_exchange_strong(expected, desired, |
| std::memory_order_relaxed, |
| std::memory_order_relaxed); |
| } |
| |
| operator T() const { return load(); } |
| T operator=(T arg) { |
| store(arg); |
| return arg; |
| } |
| T operator=(const RelaxedAtomic& arg) { |
| T loaded_once = arg; |
| store(loaded_once); |
| return loaded_once; |
| } |
| T operator+=(T arg) { return fetch_add(arg) + arg; } |
| T operator-=(T arg) { return fetch_sub(arg) - arg; } |
| |
| private: |
| std::atomic<T> value_; |
| }; |
| |
| } // namespace dart |
| |
| #endif // RUNTIME_PLATFORM_ATOMIC_H_ |