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___PSTL_BACKENDS_STD_THREAD_H
 10#define _LIBCPP___PSTL_BACKENDS_STD_THREAD_H
 11
 12#include <__config>
 13#include <__pstl/backend_fwd.h>
 14#include <__pstl/cpu_algos/any_of.h>
 15#include <__pstl/cpu_algos/cpu_traits.h>
 16#include <__pstl/cpu_algos/fill.h>
 17#include <__pstl/cpu_algos/find_if.h>
 18#include <__pstl/cpu_algos/for_each.h>
 19#include <__pstl/cpu_algos/merge.h>
 20#include <__pstl/cpu_algos/stable_sort.h>
 21#include <__pstl/cpu_algos/transform.h>
 22#include <__pstl/cpu_algos/transform_reduce.h>
 23#include <__utility/empty.h>
 24#include <__utility/move.h>
 25#include <optional>
 26
 27#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 28#  pragma GCC system_header
 29#endif
 30
 31_LIBCPP_PUSH_MACROS
 32#include <__undef_macros>
 33
 34#if _LIBCPP_STD_VER >= 17
 35
 36_LIBCPP_BEGIN_NAMESPACE_STD
 37namespace __pstl {
 38
 39//
 40// This partial backend implementation is for testing purposes only and not meant for production use. This will be
 41// replaced by a proper implementation once the PSTL implementation is somewhat stable.
 42//
 43// This is intended to be used on top of the "default backend".
 44//
 45
 46template <>
 47struct __cpu_traits<__std_thread_backend_tag> {
 48  template <class _RandomAccessIterator, class _Fp>
 49  _LIBCPP_HIDE_FROM_ABI static optional<__empty>
 50  __for_each(_RandomAccessIterator __first, _RandomAccessIterator __last, _Fp __f) {
 51    __f(__first, __last);
 52    return __empty{};
 53  }
 54
 55  template <class _Index, class _UnaryOp, class _Tp, class _BinaryOp, class _Reduce>
 56  _LIBCPP_HIDE_FROM_ABI static optional<_Tp>
 57  __transform_reduce(_Index __first, _Index __last, _UnaryOp, _Tp __init, _BinaryOp, _Reduce __reduce) {
 58    return __reduce(std::move(__first), std::move(__last), std::move(__init));
 59  }
 60
 61  template <class _RandomAccessIterator, class _Compare, class _LeafSort>
 62  _LIBCPP_HIDE_FROM_ABI static optional<__empty>
 63  __stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp, _LeafSort __leaf_sort) {
 64    __leaf_sort(__first, __last, __comp);
 65    return __empty{};
 66  }
 67
 68  _LIBCPP_HIDE_FROM_ABI static void __cancel_execution() {}
 69
 70  template <class _RandomAccessIterator1,
 71            class _RandomAccessIterator2,
 72            class _RandomAccessIterator3,
 73            class _Compare,
 74            class _LeafMerge>
 75  _LIBCPP_HIDE_FROM_ABI static optional<__empty>
 76  __merge(_RandomAccessIterator1 __first1,
 77          _RandomAccessIterator1 __last1,
 78          _RandomAccessIterator2 __first2,
 79          _RandomAccessIterator2 __last2,
 80          _RandomAccessIterator3 __outit,
 81          _Compare __comp,
 82          _LeafMerge __leaf_merge) {
 83    __leaf_merge(__first1, __last1, __first2, __last2, __outit, __comp);
 84    return __empty{};
 85  }
 86
 87  static constexpr size_t __lane_size = 64;
 88};
 89
 90// Mandatory implementations of the computational basis
 91template <class _ExecutionPolicy>
 92struct __find_if<__std_thread_backend_tag, _ExecutionPolicy>
 93    : __cpu_parallel_find_if<__std_thread_backend_tag, _ExecutionPolicy> {};
 94
 95template <class _ExecutionPolicy>
 96struct __for_each<__std_thread_backend_tag, _ExecutionPolicy>
 97    : __cpu_parallel_for_each<__std_thread_backend_tag, _ExecutionPolicy> {};
 98
 99template <class _ExecutionPolicy>
100struct __merge<__std_thread_backend_tag, _ExecutionPolicy>
101    : __cpu_parallel_merge<__std_thread_backend_tag, _ExecutionPolicy> {};
102
103template <class _ExecutionPolicy>
104struct __stable_sort<__std_thread_backend_tag, _ExecutionPolicy>
105    : __cpu_parallel_stable_sort<__std_thread_backend_tag, _ExecutionPolicy> {};
106
107template <class _ExecutionPolicy>
108struct __transform<__std_thread_backend_tag, _ExecutionPolicy>
109    : __cpu_parallel_transform<__std_thread_backend_tag, _ExecutionPolicy> {};
110
111template <class _ExecutionPolicy>
112struct __transform_binary<__std_thread_backend_tag, _ExecutionPolicy>
113    : __cpu_parallel_transform_binary<__std_thread_backend_tag, _ExecutionPolicy> {};
114
115template <class _ExecutionPolicy>
116struct __transform_reduce<__std_thread_backend_tag, _ExecutionPolicy>
117    : __cpu_parallel_transform_reduce<__std_thread_backend_tag, _ExecutionPolicy> {};
118
119template <class _ExecutionPolicy>
120struct __transform_reduce_binary<__std_thread_backend_tag, _ExecutionPolicy>
121    : __cpu_parallel_transform_reduce_binary<__std_thread_backend_tag, _ExecutionPolicy> {};
122
123// Not mandatory, but better optimized
124template <class _ExecutionPolicy>
125struct __any_of<__std_thread_backend_tag, _ExecutionPolicy>
126    : __cpu_parallel_any_of<__std_thread_backend_tag, _ExecutionPolicy> {};
127
128template <class _ExecutionPolicy>
129struct __fill<__std_thread_backend_tag, _ExecutionPolicy>
130    : __cpu_parallel_fill<__std_thread_backend_tag, _ExecutionPolicy> {};
131
132} // namespace __pstl
133_LIBCPP_END_NAMESPACE_STD
134
135#endif // _LIBCPP_STD_VER >= 17
136
137_LIBCPP_POP_MACROS
138
139#endif // _LIBCPP___PSTL_BACKENDS_STD_THREAD_H