v1/__atomic/support.h

0001 //===----------------------------------------------------------------------===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008
0009 #ifndef _LIBCPP___ATOMIC_SUPPORT_H
0010 #define _LIBCPP___ATOMIC_SUPPORT_H
0011
0012 #include <__config>
0013 #include <__type_traits/is_trivially_copyable.h>
0014
0015 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0016 #  pragma GCC system_header
0017 #endif
0018
0019 //
0020 // This file implements base support for atomics on the platform.
0021 //
0022 // The following operations and types must be implemented (where _Atmc
0023 // is __cxx_atomic_base_impl for readability):
0024 //
0025 // clang-format off
0026 //
0027 // template <class _Tp>
0028 // struct __cxx_atomic_base_impl;
0029 //
0030 // #define __cxx_atomic_is_lock_free(__size)
0031 //
0032 // void __cxx_atomic_thread_fence(memory_order __order) noexcept;
0033 // void __cxx_atomic_signal_fence(memory_order __order) noexcept;
0034 //
0035 // template <class _Tp>
0036 // void __cxx_atomic_init(_Atmc<_Tp> volatile* __a, _Tp __val) noexcept;
0037 // template <class _Tp>
0038 // void __cxx_atomic_init(_Atmc<_Tp>* __a, _Tp __val) noexcept;
0039 //
0040 // template <class _Tp>
0041 // void __cxx_atomic_store(_Atmc<_Tp> volatile* __a, _Tp __val, memory_order __order) noexcept;
0042 // template <class _Tp>
0043 // void __cxx_atomic_store(_Atmc<_Tp>* __a, _Tp __val, memory_order __order) noexcept;
0044 //
0045 // template <class _Tp>
0046 // _Tp __cxx_atomic_load(_Atmc<_Tp> const volatile* __a, memory_order __order) noexcept;
0047 // template <class _Tp>
0048 // _Tp __cxx_atomic_load(_Atmc<_Tp> const* __a, memory_order __order) noexcept;
0049 //
0050 // template <class _Tp>
0051 // void __cxx_atomic_load_inplace(_Atmc<_Tp> const volatile* __a, _Tp* __dst, memory_order __order) noexcept;
0052 // template <class _Tp>
0053 // void __cxx_atomic_load_inplace(_Atmc<_Tp> const* __a, _Tp* __dst, memory_order __order) noexcept;
0054 //
0055 // template <class _Tp>
0056 // _Tp __cxx_atomic_exchange(_Atmc<_Tp> volatile* __a, _Tp __value, memory_order __order) noexcept;
0057 // template <class _Tp>
0058 // _Tp __cxx_atomic_exchange(_Atmc<_Tp>* __a, _Tp __value, memory_order __order) noexcept;
0059 //
0060 // template <class _Tp>
0061 // bool __cxx_atomic_compare_exchange_strong(_Atmc<_Tp> volatile* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) noexcept;
0062 // template <class _Tp>
0063 // bool __cxx_atomic_compare_exchange_strong(_Atmc<_Tp>* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) noexcept;
0064 //
0065 // template <class _Tp>
0066 // bool __cxx_atomic_compare_exchange_weak(_Atmc<_Tp> volatile* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) noexcept;
0067 // template <class _Tp>
0068 // bool __cxx_atomic_compare_exchange_weak(_Atmc<_Tp>* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) noexcept;
0069 //
0070 // template <class _Tp>
0071 // _Tp __cxx_atomic_fetch_add(_Atmc<_Tp> volatile* __a, _Tp __delta, memory_order __order) noexcept;
0072 // template <class _Tp>
0073 // _Tp __cxx_atomic_fetch_add(_Atmc<_Tp>* __a, _Tp __delta, memory_order __order) noexcept;
0074 //
0075 // template <class _Tp>
0076 // _Tp* __cxx_atomic_fetch_add(_Atmc<_Tp*> volatile* __a, ptrdiff_t __delta, memory_order __order) noexcept;
0077 // template <class _Tp>
0078 // _Tp* __cxx_atomic_fetch_add(_Atmc<_Tp*>* __a, ptrdiff_t __delta, memory_order __order) noexcept;
0079 //
0080 // template <class _Tp>
0081 // _Tp __cxx_atomic_fetch_sub(_Atmc<_Tp> volatile* __a, _Tp __delta, memory_order __order) noexcept;
0082 // template <class _Tp>
0083 // _Tp __cxx_atomic_fetch_sub(_Atmc<_Tp>* __a, _Tp __delta, memory_order __order) noexcept;
0084 // template <class _Tp>
0085 // _Tp* __cxx_atomic_fetch_sub(_Atmc<_Tp*> volatile* __a, ptrdiff_t __delta, memory_order __order) noexcept;
0086 // template <class _Tp>
0087 // _Tp* __cxx_atomic_fetch_sub(_Atmc<_Tp*>* __a, ptrdiff_t __delta, memory_order __order) noexcept;
0088 //
0089 // template <class _Tp>
0090 // _Tp __cxx_atomic_fetch_and(_Atmc<_Tp> volatile* __a, _Tp __pattern, memory_order __order) noexcept;
0091 // template <class _Tp>
0092 // _Tp __cxx_atomic_fetch_and(_Atmc<_Tp>* __a, _Tp __pattern, memory_order __order) noexcept;
0093 //
0094 // template <class _Tp>
0095 // _Tp __cxx_atomic_fetch_or(_Atmc<_Tp> volatile* __a, _Tp __pattern, memory_order __order) noexcept;
0096 // template <class _Tp>
0097 // _Tp __cxx_atomic_fetch_or(_Atmc<_Tp>* __a, _Tp __pattern, memory_order __order) noexcept;
0098 // template <class _Tp>
0099 // _Tp __cxx_atomic_fetch_xor(_Atmc<_Tp> volatile* __a, _Tp __pattern, memory_order __order) noexcept;
0100 // template <class _Tp>
0101 // _Tp __cxx_atomic_fetch_xor(_Atmc<_Tp>* __a, _Tp __pattern, memory_order __order) noexcept;
0102 //
0103 // clang-format on
0104 //
0105
0106 #if _LIBCPP_HAS_GCC_ATOMIC_IMP
0107 #  include <__atomic/support/gcc.h>
0108 #elif _LIBCPP_HAS_C_ATOMIC_IMP
0109 #  include <__atomic/support/c11.h>
0110 #endif
0111
0112 _LIBCPP_BEGIN_NAMESPACE_STD
0113
0114 template <typename _Tp, typename _Base = __cxx_atomic_base_impl<_Tp> >
0115 struct __cxx_atomic_impl : public _Base {
0116   static_assert(is_trivially_copyable<_Tp>::value, "std::atomic<T> requires that 'T' be a trivially copyable type");
0117
0118   _LIBCPP_HIDE_FROM_ABI __cxx_atomic_impl() _NOEXCEPT = default;
0119   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __cxx_atomic_impl(_Tp __value) _NOEXCEPT : _Base(__value) {}
0120 };
0121
0122 _LIBCPP_END_NAMESPACE_STD
0123
0124 #endif // _LIBCPP___ATOMIC_SUPPORT_H