368faacac7
This commit reverts 5aaefa51 (and also partly 7f285f48e77 and b6d75682f9, which were related to the original commit). As landed, 5aaefa51 had unintended consequences on some downstream bots and didn't have proper coverage upstream due to a few subtle things. Implementing this is something we should do in libc++, however we'll first need to address a few issues listed in https://reviews.llvm.org/D106124#3349710. Differential Revision: https://reviews.llvm.org/D120683
111 lines
3.3 KiB
C++
111 lines
3.3 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___MEMORY_CONSTRUCT_AT_H
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#define _LIBCPP___MEMORY_CONSTRUCT_AT_H
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#include <__assert>
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#include <__config>
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#include <__iterator/access.h>
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#include <__memory/addressof.h>
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#include <__memory/voidify.h>
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#include <__utility/forward.h>
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#include <__utility/move.h>
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#include <type_traits>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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// construct_at
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#if _LIBCPP_STD_VER > 17
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template<class _Tp, class ..._Args, class = decltype(
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::new (declval<void*>()) _Tp(declval<_Args>()...)
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)>
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_LIBCPP_HIDE_FROM_ABI
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constexpr _Tp* construct_at(_Tp* __location, _Args&& ...__args) {
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_LIBCPP_ASSERT(__location, "null pointer given to construct_at");
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return ::new (_VSTD::__voidify(*__location)) _Tp(_VSTD::forward<_Args>(__args)...);
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}
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#endif
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// destroy_at
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// The internal functions are available regardless of the language version (with the exception of the `__destroy_at`
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// taking an array).
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template <class _ForwardIterator>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
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_ForwardIterator __destroy(_ForwardIterator, _ForwardIterator);
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template <class _Tp, typename enable_if<!is_array<_Tp>::value, int>::type = 0>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
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void __destroy_at(_Tp* __loc) {
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_LIBCPP_ASSERT(__loc, "null pointer given to destroy_at");
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__loc->~_Tp();
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}
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#if _LIBCPP_STD_VER > 17
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template <class _Tp, typename enable_if<is_array<_Tp>::value, int>::type = 0>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
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void __destroy_at(_Tp* __loc) {
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_LIBCPP_ASSERT(__loc, "null pointer given to destroy_at");
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_VSTD::__destroy(_VSTD::begin(*__loc), _VSTD::end(*__loc));
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}
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#endif
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template <class _ForwardIterator>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
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_ForwardIterator __destroy(_ForwardIterator __first, _ForwardIterator __last) {
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for (; __first != __last; ++__first)
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_VSTD::__destroy_at(_VSTD::addressof(*__first));
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return __first;
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}
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#if _LIBCPP_STD_VER > 14
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template <class _Tp, enable_if_t<!is_array_v<_Tp>, int> = 0>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
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void destroy_at(_Tp* __loc) {
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_VSTD::__destroy_at(__loc);
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}
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#if _LIBCPP_STD_VER > 17
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template <class _Tp, enable_if_t<is_array_v<_Tp>, int> = 0>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
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void destroy_at(_Tp* __loc) {
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_VSTD::__destroy_at(__loc);
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}
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#endif
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template <class _ForwardIterator>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
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void destroy(_ForwardIterator __first, _ForwardIterator __last) {
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(void)_VSTD::__destroy(_VSTD::move(__first), _VSTD::move(__last));
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}
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template <class _ForwardIterator, class _Size>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
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_ForwardIterator destroy_n(_ForwardIterator __first, _Size __n) {
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for (; __n > 0; (void)++__first, --__n)
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_VSTD::__destroy_at(_VSTD::addressof(*__first));
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return __first;
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}
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#endif // _LIBCPP_STD_VER > 14
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___MEMORY_CONSTRUCT_AT_H
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