Louis Dionne bd3f5a4bd3
[libc++][pstl] Improve exception handling (#88998)
There were various places where we incorrectly handled exceptions in the
PSTL. Typical issues were missing `noexcept` and taking iterators by
value instead of by reference.

This patch fixes those inconsistent and incorrect instances, and adds
proper tests for all of those. Note that the previous tests were often
incorrectly turned into no-ops by the compiler due to copy ellision,
which doesn't happen with these new tests.
2024-05-22 12:39:21 -07:00

127 lines
5.1 KiB
C++

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___ALGORITHM_PSTL_COUNT_H
#define _LIBCPP___ALGORITHM_PSTL_COUNT_H
#include <__algorithm/count.h>
#include <__algorithm/for_each.h>
#include <__algorithm/pstl_for_each.h>
#include <__algorithm/pstl_frontend_dispatch.h>
#include <__atomic/atomic.h>
#include <__config>
#include <__functional/operations.h>
#include <__iterator/cpp17_iterator_concepts.h>
#include <__iterator/iterator_traits.h>
#include <__numeric/pstl_transform_reduce.h>
#include <__pstl/configuration.h>
#include <__type_traits/enable_if.h>
#include <__type_traits/is_execution_policy.h>
#include <__type_traits/remove_cvref.h>
#include <__utility/move.h>
#include <optional>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
_LIBCPP_BEGIN_NAMESPACE_STD
template <class>
void __pstl_count_if(); // declaration needed for the frontend dispatch below
template <class _ExecutionPolicy,
class _ForwardIterator,
class _Predicate,
class _RawPolicy = __remove_cvref_t<_ExecutionPolicy>,
enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__iter_diff_t<_ForwardIterator>> __count_if(
_ExecutionPolicy&& __policy, _ForwardIterator&& __first, _ForwardIterator&& __last, _Predicate&& __pred) noexcept {
using __diff_t = __iter_diff_t<_ForwardIterator>;
return std::__pstl_frontend_dispatch(
_LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_count_if, _RawPolicy),
[&](_ForwardIterator __g_first, _ForwardIterator __g_last, _Predicate __g_pred) -> optional<__diff_t> {
return std::__transform_reduce(
__policy,
std::move(__g_first),
std::move(__g_last),
__diff_t(),
std::plus{},
[&](__iter_reference<_ForwardIterator> __element) -> bool { return __g_pred(__element); });
},
std::move(__first),
std::move(__last),
std::move(__pred));
}
template <class _ExecutionPolicy,
class _ForwardIterator,
class _Predicate,
class _RawPolicy = __remove_cvref_t<_ExecutionPolicy>,
enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
_LIBCPP_HIDE_FROM_ABI __iter_diff_t<_ForwardIterator>
count_if(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) {
_LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(
_ForwardIterator, "count_if(first, last, pred) requires [first, last) to be ForwardIterators");
auto __res = std::__count_if(__policy, std::move(__first), std::move(__last), std::move(__pred));
if (!__res)
std::__throw_bad_alloc();
return *std::move(__res);
}
template <class>
void __pstl_count(); // declaration needed for the frontend dispatch below
template <class _ExecutionPolicy,
class _ForwardIterator,
class _Tp,
class _RawPolicy = __remove_cvref_t<_ExecutionPolicy>,
enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__iter_diff_t<_ForwardIterator>> __count(
_ExecutionPolicy&& __policy, _ForwardIterator&& __first, _ForwardIterator&& __last, const _Tp& __value) noexcept {
return std::__pstl_frontend_dispatch(
_LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_count, _RawPolicy),
[&](_ForwardIterator __g_first, _ForwardIterator __g_last, const _Tp& __g_value)
-> optional<__iter_diff_t<_ForwardIterator>> {
return std::count_if(__policy, __g_first, __g_last, [&](__iter_reference<_ForwardIterator> __v) {
return __v == __g_value;
});
},
std::forward<_ForwardIterator>(__first),
std::forward<_ForwardIterator>(__last),
__value);
}
template <class _ExecutionPolicy,
class _ForwardIterator,
class _Tp,
class _RawPolicy = __remove_cvref_t<_ExecutionPolicy>,
enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
_LIBCPP_HIDE_FROM_ABI __iter_diff_t<_ForwardIterator>
count(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
_LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(
_ForwardIterator, "count(first, last, val) requires [first, last) to be ForwardIterators");
auto __res = std::__count(__policy, std::move(__first), std::move(__last), __value);
if (!__res)
std::__throw_bad_alloc();
return *__res;
}
_LIBCPP_END_NAMESPACE_STD
#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
_LIBCPP_POP_MACROS
#endif // _LIBCPP___ALGORITHM_PSTL_COUNT_H