3b8faee6c6
This makes the placement of the attribute more consistent. This also avoids clang dropping the attribute silently (see #120722).
76 lines
2.7 KiB
C++
76 lines
2.7 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_ALLOCATOR_ARG_T_H
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#define _LIBCPP___MEMORY_ALLOCATOR_ARG_T_H
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#include <__config>
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#include <__memory/uses_allocator.h>
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#include <__type_traits/integral_constant.h>
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#include <__type_traits/is_constructible.h>
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#include <__type_traits/remove_cvref.h>
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#include <__utility/forward.h>
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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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struct _LIBCPP_TEMPLATE_VIS allocator_arg_t {
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explicit allocator_arg_t() = default;
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};
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#if _LIBCPP_STD_VER >= 17
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inline constexpr allocator_arg_t allocator_arg = allocator_arg_t();
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#elif !defined(_LIBCPP_CXX03_LANG)
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constexpr allocator_arg_t allocator_arg = allocator_arg_t();
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#endif
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#ifndef _LIBCPP_CXX03_LANG
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// allocator construction
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template <class _Tp, class _Alloc, class... _Args>
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struct __uses_alloc_ctor_imp {
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using _RawAlloc _LIBCPP_NODEBUG = __remove_cvref_t<_Alloc>;
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static const bool __ua = uses_allocator<_Tp, _RawAlloc>::value;
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static const bool __ic = is_constructible<_Tp, allocator_arg_t, _Alloc, _Args...>::value;
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static const int value = __ua ? 2 - __ic : 0;
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};
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template <class _Tp, class _Alloc, class... _Args>
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struct __uses_alloc_ctor : integral_constant<int, __uses_alloc_ctor_imp<_Tp, _Alloc, _Args...>::value> {};
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template <class _Tp, class _Allocator, class... _Args>
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inline _LIBCPP_HIDE_FROM_ABI void
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__user_alloc_construct_impl(integral_constant<int, 0>, _Tp* __storage, const _Allocator&, _Args&&... __args) {
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new (__storage) _Tp(std::forward<_Args>(__args)...);
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}
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// FIXME: This should have a version which takes a non-const alloc.
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template <class _Tp, class _Allocator, class... _Args>
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inline _LIBCPP_HIDE_FROM_ABI void
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__user_alloc_construct_impl(integral_constant<int, 1>, _Tp* __storage, const _Allocator& __a, _Args&&... __args) {
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new (__storage) _Tp(allocator_arg, __a, std::forward<_Args>(__args)...);
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}
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// FIXME: This should have a version which takes a non-const alloc.
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template <class _Tp, class _Allocator, class... _Args>
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inline _LIBCPP_HIDE_FROM_ABI void
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__user_alloc_construct_impl(integral_constant<int, 2>, _Tp* __storage, const _Allocator& __a, _Args&&... __args) {
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new (__storage) _Tp(std::forward<_Args>(__args)..., __a);
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}
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#endif // _LIBCPP_CXX03_LANG
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___MEMORY_ALLOCATOR_ARG_T_H
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