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 <__config>
36#include <__type_traits/is_execution_policy.h>
37#include <__type_traits/is_same.h>
38#include <__type_traits/remove_cvref.h>
39#include <version>
40
41#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
42# pragma GCC system_header
43#endif
44
45#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
46
47_LIBCPP_BEGIN_NAMESPACE_STD
48
49namespace execution {
50struct sequenced_policy {
51 _LIBCPP_HIDE_FROM_ABI constexpr explicit sequenced_policy(__disable_user_instantiations_tag) {}
52 sequenced_policy(const sequenced_policy&) = delete;
53 sequenced_policy& operator=(const sequenced_policy&) = delete;
54};
55
56inline constexpr sequenced_policy seq{__disable_user_instantiations_tag{}};
57
58struct parallel_policy {
59 _LIBCPP_HIDE_FROM_ABI constexpr explicit parallel_policy(__disable_user_instantiations_tag) {}
60 parallel_policy(const parallel_policy&) = delete;
61 parallel_policy& operator=(const parallel_policy&) = delete;
62};
63
64inline constexpr parallel_policy par{__disable_user_instantiations_tag{}};
65
66struct parallel_unsequenced_policy {
67 _LIBCPP_HIDE_FROM_ABI constexpr explicit parallel_unsequenced_policy(__disable_user_instantiations_tag) {}
68 parallel_unsequenced_policy(const parallel_unsequenced_policy&) = delete;
69 parallel_unsequenced_policy& operator=(const parallel_unsequenced_policy&) = delete;
70};
71
72inline constexpr parallel_unsequenced_policy par_unseq{__disable_user_instantiations_tag{}};
73
74struct __unsequenced_policy {
75 _LIBCPP_HIDE_FROM_ABI constexpr explicit __unsequenced_policy(__disable_user_instantiations_tag) {}
76 __unsequenced_policy(const __unsequenced_policy&) = delete;
77 __unsequenced_policy& operator=(const __unsequenced_policy&) = delete;
78};
79
80constexpr __unsequenced_policy __unseq{__disable_user_instantiations_tag{}};
81
82# if _LIBCPP_STD_VER >= 20
83
84struct unsequenced_policy {
85 _LIBCPP_HIDE_FROM_ABI constexpr explicit unsequenced_policy(__disable_user_instantiations_tag) {}
86 unsequenced_policy(const unsequenced_policy&) = delete;
87 unsequenced_policy& operator=(const unsequenced_policy&) = delete;
88};
89
90inline constexpr unsequenced_policy unseq{__disable_user_instantiations_tag{}};
91
92# endif // _LIBCPP_STD_VER >= 20
93
94} // namespace execution
95
96template <>
97inline constexpr bool is_execution_policy_v<execution::sequenced_policy> = true;
98
99template <>
100inline constexpr bool is_execution_policy_v<execution::parallel_policy> = true;
101
102template <>
103inline constexpr bool is_execution_policy_v<execution::parallel_unsequenced_policy> = true;
104
105template <>
106inline constexpr bool is_execution_policy_v<execution::__unsequenced_policy> = true;
107
108template <>
109inline constexpr bool __is_parallel_execution_policy_impl<execution::parallel_policy> = true;
110
111template <>
112inline constexpr bool __is_parallel_execution_policy_impl<execution::parallel_unsequenced_policy> = true;
113
114template <>
115inline constexpr bool __is_unsequenced_execution_policy_impl<execution::__unsequenced_policy> = true;
116
117template <>
118inline constexpr bool __is_unsequenced_execution_policy_impl<execution::parallel_unsequenced_policy> = true;
119
120# if _LIBCPP_STD_VER >= 20
121template <>
122inline constexpr bool is_execution_policy_v<execution::unsequenced_policy> = true;
123
124template <>
125inline constexpr bool __is_unsequenced_execution_policy_impl<execution::unsequenced_policy> = true;
126
127# endif
128
129template <class _Tp>
130struct is_execution_policy : bool_constant<is_execution_policy_v<_Tp>> {};
131
132template <class _ExecutionPolicy>
133_LIBCPP_HIDE_FROM_ABI auto __remove_parallel_policy(const _ExecutionPolicy&) {
134 if constexpr (is_same_v<_ExecutionPolicy, execution::parallel_policy>) {
135 return execution::sequenced_policy(execution::__disable_user_instantiations_tag{});
136 } else if constexpr (is_same_v<_ExecutionPolicy, execution::parallel_unsequenced_policy>) {
137 return execution::__unsequenced_policy{execution::__disable_user_instantiations_tag{}};
138 }
139}
140
141_LIBCPP_END_NAMESPACE_STD
142
143#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
144
145#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
146# include <cstddef>
147#endif
148
149#endif // _LIBCPP_EXECUTION
150