libcxx/include/__atomic/support.h

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef _LIBCPP___ATOMIC_SUPPORT_H
  10 #define _LIBCPP___ATOMIC_SUPPORT_H
  11
  12 #include <__config>
  13 #include <__type_traits/is_trivially_copyable.h>
  14
  15 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  16 #  pragma GCC system_header
  17 #endif
  18
  19 //
  20 // This file implements base support for atomics on the platform.
  21 //
  22 // The following operations and types must be implemented (where _Atmc
  23 // is __cxx_atomic_base_impl for readability):
  24 //
  25 // clang-format off
  26 //
  27 // template <class _Tp>
  28 // struct __cxx_atomic_base_impl;
  29 //
  30 // #define __cxx_atomic_is_lock_free(__size)
  31 //
  32 // void __cxx_atomic_thread_fence(memory_order __order) noexcept;
  33 // void __cxx_atomic_signal_fence(memory_order __order) noexcept;
  34 //
  35 // template <class _Tp>
  36 // void __cxx_atomic_init(_Atmc<_Tp> volatile* __a, _Tp __val) noexcept;
  37 // template <class _Tp>
  38 // void __cxx_atomic_init(_Atmc<_Tp>* __a, _Tp __val) noexcept;
  39 //
  40 // template <class _Tp>
  41 // void __cxx_atomic_store(_Atmc<_Tp> volatile* __a, _Tp __val, memory_order __order) noexcept;
  42 // template <class _Tp>
  43 // void __cxx_atomic_store(_Atmc<_Tp>* __a, _Tp __val, memory_order __order) noexcept;
  44 //
  45 // template <class _Tp>
  46 // _Tp __cxx_atomic_load(_Atmc<_Tp> const volatile* __a, memory_order __order) noexcept;
  47 // template <class _Tp>
  48 // _Tp __cxx_atomic_load(_Atmc<_Tp> const* __a, memory_order __order) noexcept;
  49 //
  50 // template <class _Tp>
  51 // void __cxx_atomic_load_inplace(_Atmc<_Tp> const volatile* __a, _Tp* __dst, memory_order __order) noexcept;
  52 // template <class _Tp>
  53 // void __cxx_atomic_load_inplace(_Atmc<_Tp> const* __a, _Tp* __dst, memory_order __order) noexcept;
  54 //
  55 // template <class _Tp>
  56 // _Tp __cxx_atomic_exchange(_Atmc<_Tp> volatile* __a, _Tp __value, memory_order __order) noexcept;
  57 // template <class _Tp>
  58 // _Tp __cxx_atomic_exchange(_Atmc<_Tp>* __a, _Tp __value, memory_order __order) noexcept;
  59 //
  60 // template <class _Tp>
  61 // bool __cxx_atomic_compare_exchange_strong(_Atmc<_Tp> volatile* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) noexcept;
  62 // template <class _Tp>
  63 // bool __cxx_atomic_compare_exchange_strong(_Atmc<_Tp>* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) noexcept;
  64 //
  65 // template <class _Tp>
  66 // bool __cxx_atomic_compare_exchange_weak(_Atmc<_Tp> volatile* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) noexcept;
  67 // template <class _Tp>
  68 // bool __cxx_atomic_compare_exchange_weak(_Atmc<_Tp>* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) noexcept;
  69 //
  70 // template <class _Tp>
  71 // _Tp __cxx_atomic_fetch_add(_Atmc<_Tp> volatile* __a, _Tp __delta, memory_order __order) noexcept;
  72 // template <class _Tp>
  73 // _Tp __cxx_atomic_fetch_add(_Atmc<_Tp>* __a, _Tp __delta, memory_order __order) noexcept;
  74 //
  75 // template <class _Tp>
  76 // _Tp* __cxx_atomic_fetch_add(_Atmc<_Tp*> volatile* __a, ptrdiff_t __delta, memory_order __order) noexcept;
  77 // template <class _Tp>
  78 // _Tp* __cxx_atomic_fetch_add(_Atmc<_Tp*>* __a, ptrdiff_t __delta, memory_order __order) noexcept;
  79 //
  80 // template <class _Tp>
  81 // _Tp __cxx_atomic_fetch_sub(_Atmc<_Tp> volatile* __a, _Tp __delta, memory_order __order) noexcept;
  82 // template <class _Tp>
  83 // _Tp __cxx_atomic_fetch_sub(_Atmc<_Tp>* __a, _Tp __delta, memory_order __order) noexcept;
  84 // template <class _Tp>
  85 // _Tp* __cxx_atomic_fetch_sub(_Atmc<_Tp*> volatile* __a, ptrdiff_t __delta, memory_order __order) noexcept;
  86 // template <class _Tp>
  87 // _Tp* __cxx_atomic_fetch_sub(_Atmc<_Tp*>* __a, ptrdiff_t __delta, memory_order __order) noexcept;
  88 //
  89 // template <class _Tp>
  90 // _Tp __cxx_atomic_fetch_and(_Atmc<_Tp> volatile* __a, _Tp __pattern, memory_order __order) noexcept;
  91 // template <class _Tp>
  92 // _Tp __cxx_atomic_fetch_and(_Atmc<_Tp>* __a, _Tp __pattern, memory_order __order) noexcept;
  93 //
  94 // template <class _Tp>
  95 // _Tp __cxx_atomic_fetch_or(_Atmc<_Tp> volatile* __a, _Tp __pattern, memory_order __order) noexcept;
  96 // template <class _Tp>
  97 // _Tp __cxx_atomic_fetch_or(_Atmc<_Tp>* __a, _Tp __pattern, memory_order __order) noexcept;
  98 // template <class _Tp>
  99 // _Tp __cxx_atomic_fetch_xor(_Atmc<_Tp> volatile* __a, _Tp __pattern, memory_order __order) noexcept;
 100 // template <class _Tp>
 101 // _Tp __cxx_atomic_fetch_xor(_Atmc<_Tp>* __a, _Tp __pattern, memory_order __order) noexcept;
 102 //
 103 // clang-format on
 104 //
 105
 106 #if _LIBCPP_HAS_GCC_ATOMIC_IMP
 107 #  include <__atomic/support/gcc.h>
 108 #elif _LIBCPP_HAS_C_ATOMIC_IMP
 109 #  include <__atomic/support/c11.h>
 110 #endif
 111
 112 _LIBCPP_BEGIN_NAMESPACE_STD
 113
 114 template <typename _Tp, typename _Base = __cxx_atomic_base_impl<_Tp> >
 115 struct __cxx_atomic_impl : public _Base {
 116   static_assert(is_trivially_copyable<_Tp>::value, "std::atomic<T> requires that 'T' be a trivially copyable type");
 117
 118   _LIBCPP_HIDE_FROM_ABI __cxx_atomic_impl() _NOEXCEPT = default;
 119   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __cxx_atomic_impl(_Tp __value) _NOEXCEPT : _Base(__value) {}
 120 };
 121
 122 _LIBCPP_END_NAMESPACE_STD
 123
 124 #endif // _LIBCPP___ATOMIC_SUPPORT_H