c0cde79e9e
As explained in the release note, libc++ used to provide various global variables as an extension in C++03 mode. Unfortunately, that made our definition non-conforming in all standard modes. This was never a big problem until recently, since we are trying to support C++20 Modules in libc++, and that requires cleaning up the definition of these variables. This change is the first in a series of changes to achieve our end goal. This patch removes the ability for users to rely on the (incorrect) definition of those global variables inside the shared library. The plan is to then remove those definitions from the shared library (which is an ABI break but I don't think it will have impact), and finally to make our definition of those variables conforming in all standard modes. Differential Revision: https://reviews.llvm.org/D145422
81 lines
2.7 KiB
C++
81 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___FUNCTIONAL_ALLOCATOR_ARG_T_H
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#define _LIBCPP___FUNCTIONAL_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 { explicit allocator_arg_t() = default; };
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#if defined(_LIBCPP_BUILDING_LIBRARY)
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extern _LIBCPP_EXPORTED_FROM_ABI const allocator_arg_t allocator_arg;
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#elif !defined(_LIBCPP_CXX03_LANG)
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/* inline */ 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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{
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typedef _LIBCPP_NODEBUG __remove_cvref_t<_Alloc> _RawAlloc;
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static const bool __ua = uses_allocator<_Tp, _RawAlloc>::value;
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static const bool __ic =
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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
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: integral_constant<int, __uses_alloc_ctor_imp<_Tp, _Alloc, _Args...>::value>
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{};
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template <class _Tp, class _Allocator, class... _Args>
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inline _LIBCPP_INLINE_VISIBILITY
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void __user_alloc_construct_impl (integral_constant<int, 0>, _Tp *__storage, const _Allocator &, _Args &&... __args )
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{
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new (__storage) _Tp (_VSTD::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_INLINE_VISIBILITY
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void __user_alloc_construct_impl (integral_constant<int, 1>, _Tp *__storage, const _Allocator &__a, _Args &&... __args )
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{
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new (__storage) _Tp (allocator_arg, __a, _VSTD::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_INLINE_VISIBILITY
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void __user_alloc_construct_impl (integral_constant<int, 2>, _Tp *__storage, const _Allocator &__a, _Args &&... __args )
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{
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new (__storage) _Tp (_VSTD::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___FUNCTIONAL_ALLOCATOR_ARG_T_H
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