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
220 lines
6.7 KiB
C++
220 lines
6.7 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_POINTER_TRAITS_H
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#define _LIBCPP___MEMORY_POINTER_TRAITS_H
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#include <__config>
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#include <__memory/addressof.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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template <class _Tp, class = void>
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struct __has_element_type : false_type {};
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template <class _Tp>
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struct __has_element_type<_Tp,
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typename __void_t<typename _Tp::element_type>::type> : true_type {};
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template <class _Ptr, bool = __has_element_type<_Ptr>::value>
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struct __pointer_traits_element_type;
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template <class _Ptr>
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struct __pointer_traits_element_type<_Ptr, true>
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{
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typedef _LIBCPP_NODEBUG typename _Ptr::element_type type;
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};
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template <template <class, class...> class _Sp, class _Tp, class ..._Args>
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struct __pointer_traits_element_type<_Sp<_Tp, _Args...>, true>
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{
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typedef _LIBCPP_NODEBUG typename _Sp<_Tp, _Args...>::element_type type;
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};
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template <template <class, class...> class _Sp, class _Tp, class ..._Args>
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struct __pointer_traits_element_type<_Sp<_Tp, _Args...>, false>
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{
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typedef _LIBCPP_NODEBUG _Tp type;
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};
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template <class _Tp, class = void>
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struct __has_difference_type : false_type {};
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template <class _Tp>
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struct __has_difference_type<_Tp,
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typename __void_t<typename _Tp::difference_type>::type> : true_type {};
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template <class _Ptr, bool = __has_difference_type<_Ptr>::value>
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struct __pointer_traits_difference_type
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{
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typedef _LIBCPP_NODEBUG ptrdiff_t type;
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};
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template <class _Ptr>
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struct __pointer_traits_difference_type<_Ptr, true>
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{
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typedef _LIBCPP_NODEBUG typename _Ptr::difference_type type;
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};
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template <class _Tp, class _Up>
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struct __has_rebind
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{
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private:
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struct __two {char __lx; char __lxx;};
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template <class _Xp> static __two __test(...);
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_LIBCPP_SUPPRESS_DEPRECATED_PUSH
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template <class _Xp> static char __test(typename _Xp::template rebind<_Up>* = 0);
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_LIBCPP_SUPPRESS_DEPRECATED_POP
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public:
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static const bool value = sizeof(__test<_Tp>(0)) == 1;
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};
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template <class _Tp, class _Up, bool = __has_rebind<_Tp, _Up>::value>
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struct __pointer_traits_rebind
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{
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#ifndef _LIBCPP_CXX03_LANG
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typedef _LIBCPP_NODEBUG typename _Tp::template rebind<_Up> type;
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#else
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typedef _LIBCPP_NODEBUG typename _Tp::template rebind<_Up>::other type;
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#endif
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};
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template <template <class, class...> class _Sp, class _Tp, class ..._Args, class _Up>
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struct __pointer_traits_rebind<_Sp<_Tp, _Args...>, _Up, true>
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{
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#ifndef _LIBCPP_CXX03_LANG
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typedef _LIBCPP_NODEBUG typename _Sp<_Tp, _Args...>::template rebind<_Up> type;
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#else
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typedef _LIBCPP_NODEBUG typename _Sp<_Tp, _Args...>::template rebind<_Up>::other type;
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#endif
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};
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template <template <class, class...> class _Sp, class _Tp, class ..._Args, class _Up>
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struct __pointer_traits_rebind<_Sp<_Tp, _Args...>, _Up, false>
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{
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typedef _Sp<_Up, _Args...> type;
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};
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template <class _Ptr>
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struct _LIBCPP_TEMPLATE_VIS pointer_traits
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{
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typedef _Ptr pointer;
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typedef typename __pointer_traits_element_type<pointer>::type element_type;
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typedef typename __pointer_traits_difference_type<pointer>::type difference_type;
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#ifndef _LIBCPP_CXX03_LANG
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template <class _Up> using rebind = typename __pointer_traits_rebind<pointer, _Up>::type;
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#else
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template <class _Up> struct rebind
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{typedef typename __pointer_traits_rebind<pointer, _Up>::type other;};
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#endif // _LIBCPP_CXX03_LANG
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private:
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struct __nat {};
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public:
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_LIBCPP_INLINE_VISIBILITY
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static pointer pointer_to(typename conditional<is_void<element_type>::value,
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__nat, element_type>::type& __r)
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{return pointer::pointer_to(__r);}
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};
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template <class _Tp>
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struct _LIBCPP_TEMPLATE_VIS pointer_traits<_Tp*>
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{
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typedef _Tp* pointer;
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typedef _Tp element_type;
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typedef ptrdiff_t difference_type;
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#ifndef _LIBCPP_CXX03_LANG
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template <class _Up> using rebind = _Up*;
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#else
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template <class _Up> struct rebind {typedef _Up* other;};
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#endif
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private:
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struct __nat {};
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public:
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
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static pointer pointer_to(typename conditional<is_void<element_type>::value,
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__nat, element_type>::type& __r) _NOEXCEPT
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{return _VSTD::addressof(__r);}
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};
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template <class _From, class _To>
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struct __rebind_pointer {
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#ifndef _LIBCPP_CXX03_LANG
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typedef typename pointer_traits<_From>::template rebind<_To> type;
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#else
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typedef typename pointer_traits<_From>::template rebind<_To>::other type;
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#endif
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};
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// to_address
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template <class _Pointer, class = void>
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struct __to_address_helper;
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template <class _Tp>
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
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_Tp* __to_address(_Tp* __p) _NOEXCEPT {
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static_assert(!is_function<_Tp>::value, "_Tp is a function type");
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return __p;
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}
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// enable_if is needed here to avoid instantiating checks for fancy pointers on raw pointers
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template <class _Pointer, class = __enable_if_t<
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!is_pointer<_Pointer>::value && !is_array<_Pointer>::value && !is_function<_Pointer>::value
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> >
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
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typename decay<decltype(__to_address_helper<_Pointer>::__call(declval<const _Pointer&>()))>::type
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__to_address(const _Pointer& __p) _NOEXCEPT {
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return __to_address_helper<_Pointer>::__call(__p);
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}
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template <class _Pointer, class>
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struct __to_address_helper {
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
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static decltype(_VSTD::__to_address(declval<const _Pointer&>().operator->()))
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__call(const _Pointer& __p) _NOEXCEPT {
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return _VSTD::__to_address(__p.operator->());
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}
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};
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template <class _Pointer>
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struct __to_address_helper<_Pointer, decltype((void)pointer_traits<_Pointer>::to_address(declval<const _Pointer&>()))> {
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
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static decltype(pointer_traits<_Pointer>::to_address(declval<const _Pointer&>()))
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__call(const _Pointer& __p) _NOEXCEPT {
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return pointer_traits<_Pointer>::to_address(__p);
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}
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};
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#if _LIBCPP_STD_VER > 17
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template <class _Tp>
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inline _LIBCPP_INLINE_VISIBILITY constexpr
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auto to_address(_Tp *__p) noexcept {
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return _VSTD::__to_address(__p);
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}
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template <class _Pointer>
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inline _LIBCPP_INLINE_VISIBILITY constexpr
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auto to_address(const _Pointer& __p) noexcept {
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return _VSTD::__to_address(__p);
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}
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#endif
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___MEMORY_POINTER_TRAITS_H
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