1// -*- C++ -*- 2//===----------------------------------------------------------------------===// 3// 4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5// See https://llvm.org/LICENSE.txt for license information. 6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7// 8//===----------------------------------------------------------------------===// 9 10#ifndef _LIBCPP_EXECUTION 11#define _LIBCPP_EXECUTION 12 13/* 14namespace std::execution { 15 struct sequenced_policy; 16 struct parallel_policy; 17 struct parallel_unsequenced_policy; 18 struct unsequenced_policy; // since C++20 19 20 inline constexpr sequenced_policy seq = implementation-defined; 21 inline constexpr parallel_policy par = implementation-defined; 22 inline constexpr parallel_unsequenced_policy par_unseq = implementation-defined; 23 inline constexpr unsequenced_policy unseq = implementation-defined; // since C++20 24} 25 26namespace std { 27 template <class T> 28 struct is_execution_policy; 29 30 template <class T> 31 inline constexpr bool is_execution_policy_v; 32} 33*/ 34 35#include <__assert> // all public C++ headers provide the assertion handler 36#include <__config> 37#include <__type_traits/is_execution_policy.h> 38#include <__type_traits/is_same.h> 39#include <__type_traits/remove_cvref.h> 40#include <version> 41 42#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 43# pragma GCC system_header 44#endif 45 46#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17 47 48_LIBCPP_BEGIN_NAMESPACE_STD 49 50namespace execution { 51struct sequenced_policy { 52 _LIBCPP_HIDE_FROM_ABI constexpr explicit sequenced_policy(__disable_user_instantiations_tag) {} 53 sequenced_policy(const sequenced_policy&) = delete; 54 sequenced_policy& operator=(const sequenced_policy&) = delete; 55}; 56 57inline constexpr sequenced_policy seq{__disable_user_instantiations_tag{}}; 58 59struct parallel_policy { 60 _LIBCPP_HIDE_FROM_ABI constexpr explicit parallel_policy(__disable_user_instantiations_tag) {} 61 parallel_policy(const parallel_policy&) = delete; 62 parallel_policy& operator=(const parallel_policy&) = delete; 63}; 64 65inline constexpr parallel_policy par{__disable_user_instantiations_tag{}}; 66 67struct parallel_unsequenced_policy { 68 _LIBCPP_HIDE_FROM_ABI constexpr explicit parallel_unsequenced_policy(__disable_user_instantiations_tag) {} 69 parallel_unsequenced_policy(const parallel_unsequenced_policy&) = delete; 70 parallel_unsequenced_policy& operator=(const parallel_unsequenced_policy&) = delete; 71}; 72 73inline constexpr parallel_unsequenced_policy par_unseq{__disable_user_instantiations_tag{}}; 74 75struct __unsequenced_policy { 76 _LIBCPP_HIDE_FROM_ABI constexpr explicit __unsequenced_policy(__disable_user_instantiations_tag) {} 77 __unsequenced_policy(const __unsequenced_policy&) = delete; 78 __unsequenced_policy& operator=(const __unsequenced_policy&) = delete; 79}; 80 81constexpr __unsequenced_policy __unseq{__disable_user_instantiations_tag{}}; 82 83# if _LIBCPP_STD_VER >= 20 84 85struct unsequenced_policy { 86 _LIBCPP_HIDE_FROM_ABI constexpr explicit unsequenced_policy(__disable_user_instantiations_tag) {} 87 unsequenced_policy(const unsequenced_policy&) = delete; 88 unsequenced_policy& operator=(const unsequenced_policy&) = delete; 89}; 90 91inline constexpr unsequenced_policy unseq{__disable_user_instantiations_tag{}}; 92 93# endif // _LIBCPP_STD_VER >= 20 94 95} // namespace execution 96 97template <> 98inline constexpr bool is_execution_policy_v<execution::sequenced_policy> = true; 99 100template <> 101inline constexpr bool is_execution_policy_v<execution::parallel_policy> = true; 102 103template <> 104inline constexpr bool is_execution_policy_v<execution::parallel_unsequenced_policy> = true; 105 106template <> 107inline constexpr bool is_execution_policy_v<execution::__unsequenced_policy> = true; 108 109template <> 110inline constexpr bool __is_parallel_execution_policy_impl<execution::parallel_policy> = true; 111 112template <> 113inline constexpr bool __is_parallel_execution_policy_impl<execution::parallel_unsequenced_policy> = true; 114 115template <> 116inline constexpr bool __is_unsequenced_execution_policy_impl<execution::__unsequenced_policy> = true; 117 118template <> 119inline constexpr bool __is_unsequenced_execution_policy_impl<execution::parallel_unsequenced_policy> = true; 120 121# if _LIBCPP_STD_VER >= 20 122template <> 123inline constexpr bool is_execution_policy_v<execution::unsequenced_policy> = true; 124 125template <> 126inline constexpr bool __is_unsequenced_execution_policy_impl<execution::unsequenced_policy> = true; 127 128# endif 129 130template <class _Tp> 131struct is_execution_policy : bool_constant<is_execution_policy_v<_Tp>> {}; 132 133template <class _ExecutionPolicy> 134_LIBCPP_HIDE_FROM_ABI auto __remove_parallel_policy(const _ExecutionPolicy&) { 135 if constexpr (is_same_v<_ExecutionPolicy, execution::parallel_policy>) { 136 return execution::sequenced_policy(execution::__disable_user_instantiations_tag{}); 137 } else if constexpr (is_same_v<_ExecutionPolicy, execution::parallel_unsequenced_policy>) { 138 return execution::__unsequenced_policy{execution::__disable_user_instantiations_tag{}}; 139 } 140} 141 142_LIBCPP_END_NAMESPACE_STD 143 144#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17 145 146#endif // _LIBCPP_EXECUTION 147