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Howard Hinnantc51e1022010-05-11 19:42:16 +00001// -*- C++ -*-
2//===----------------------------- new ------------------------------------===//
3//
Howard Hinnantc566dc32010-05-11 21:36:01 +00004// The LLVM Compiler Infrastructure
Howard Hinnantc51e1022010-05-11 19:42:16 +00005//
Howard Hinnantee11c312010-11-16 22:09:02 +00006// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
Howard Hinnantc51e1022010-05-11 19:42:16 +00008//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_NEW
12#define _LIBCPP_NEW
13
14/*
15 new synopsis
16
17namespace std
18{
19
20class bad_alloc
21 : public exception
22{
23public:
Howard Hinnant1bc52cf2011-05-26 18:23:59 +000024 bad_alloc() noexcept;
25 bad_alloc(const bad_alloc&) noexcept;
26 bad_alloc& operator=(const bad_alloc&) noexcept;
27 virtual const char* what() const noexcept;
Howard Hinnantc51e1022010-05-11 19:42:16 +000028};
29
Eric Fiselier162922f2016-10-14 06:46:30 +000030class bad_array_length : public bad_alloc // FIXME: Not part of C++
Marshall Clow3bf77132013-09-11 01:38:42 +000031{
32public:
33 bad_array_length() noexcept;
34};
35
Eric Fiselier162922f2016-10-14 06:46:30 +000036class bad_array_new_length : public bad_alloc // C++14
Marshall Clow3bf77132013-09-11 01:38:42 +000037{
38public:
39 bad_array_new_length() noexcept;
40};
41
Eric Fiselier162922f2016-10-14 06:46:30 +000042enum class align_val_t : size_t {}; // C++17
Howard Hinnantc51e1022010-05-11 19:42:16 +000043struct nothrow_t {};
44extern const nothrow_t nothrow;
45typedef void (*new_handler)();
Howard Hinnant1bc52cf2011-05-26 18:23:59 +000046new_handler set_new_handler(new_handler new_p) noexcept;
47new_handler get_new_handler() noexcept;
Howard Hinnantc51e1022010-05-11 19:42:16 +000048
Marshall Clowdf5a11f2017-11-22 19:49:03 +000049// 21.6.4, pointer optimization barrier
50template <class T> constexpr T* launder(T* p) noexcept; // C++17
Howard Hinnantc51e1022010-05-11 19:42:16 +000051} // std
52
Marshall Clowbe8b84d2017-12-04 23:03:42 +000053void* operator new(std::size_t size); // replaceable, nodiscard in C++2a
54void* operator new(std::size_t size, std::align_val_t alignment); // replaceable, C++17, nodiscard in C++2a
55void* operator new(std::size_t size, const std::nothrow_t&) noexcept; // replaceable, nodiscard in C++2a
Eric Fiselier162922f2016-10-14 06:46:30 +000056void* operator new(std::size_t size, std::align_val_t alignment,
Marshall Clowbe8b84d2017-12-04 23:03:42 +000057 const std::nothrow_t&) noexcept; // replaceable, C++17, nodiscard in C++2a
Howard Hinnant1bc52cf2011-05-26 18:23:59 +000058void operator delete(void* ptr) noexcept; // replaceable
Larisse Voufo574190d2015-02-15 05:18:55 +000059void operator delete(void* ptr, std::size_t size) noexcept; // replaceable, C++14
Eric Fiselier162922f2016-10-14 06:46:30 +000060void operator delete(void* ptr, std::align_val_t alignment) noexcept; // replaceable, C++17
61void operator delete(void* ptr, std::size_t size,
62 std::align_val_t alignment) noexcept; // replaceable, C++17
Howard Hinnant1bc52cf2011-05-26 18:23:59 +000063void operator delete(void* ptr, const std::nothrow_t&) noexcept; // replaceable
Eric Fiselier162922f2016-10-14 06:46:30 +000064void operator delete(void* ptr, std:align_val_t alignment,
65 const std::nothrow_t&) noexcept; // replaceable, C++17
Howard Hinnantc51e1022010-05-11 19:42:16 +000066
Marshall Clowbe8b84d2017-12-04 23:03:42 +000067void* operator new[](std::size_t size); // replaceable, nodiscard in C++2a
Eric Fiselier162922f2016-10-14 06:46:30 +000068void* operator new[](std::size_t size,
Marshall Clowbe8b84d2017-12-04 23:03:42 +000069 std::align_val_t alignment) noexcept; // replaceable, C++17, nodiscard in C++2a
70void* operator new[](std::size_t size, const std::nothrow_t&) noexcept; // replaceable, nodiscard in C++2a
Eric Fiselier162922f2016-10-14 06:46:30 +000071void* operator new[](std::size_t size, std::align_val_t alignment,
Marshall Clowbe8b84d2017-12-04 23:03:42 +000072 const std::nothrow_t&) noexcept; // replaceable, C++17, nodiscard in C++2a
Howard Hinnant1bc52cf2011-05-26 18:23:59 +000073void operator delete[](void* ptr) noexcept; // replaceable
Larisse Voufo574190d2015-02-15 05:18:55 +000074void operator delete[](void* ptr, std::size_t size) noexcept; // replaceable, C++14
Eric Fiselier162922f2016-10-14 06:46:30 +000075void operator delete[](void* ptr,
76 std::align_val_t alignment) noexcept; // replaceable, C++17
77void operator delete[](void* ptr, std::size_t size,
78 std::align_val_t alignment) noexcept; // replaceable, C++17
Howard Hinnant1bc52cf2011-05-26 18:23:59 +000079void operator delete[](void* ptr, const std::nothrow_t&) noexcept; // replaceable
Eric Fiselier162922f2016-10-14 06:46:30 +000080void operator delete[](void* ptr, std::align_val_t alignment,
81 const std::nothrow_t&) noexcept; // replaceable, C++17
Howard Hinnantc51e1022010-05-11 19:42:16 +000082
Marshall Clowbe8b84d2017-12-04 23:03:42 +000083void* operator new (std::size_t size, void* ptr) noexcept; // nodiscard in C++2a
84void* operator new[](std::size_t size, void* ptr) noexcept; // nodiscard in C++2a
Howard Hinnant1bc52cf2011-05-26 18:23:59 +000085void operator delete (void* ptr, void*) noexcept;
86void operator delete[](void* ptr, void*) noexcept;
Howard Hinnantc51e1022010-05-11 19:42:16 +000087
88*/
89
90#include <__config>
91#include <exception>
Eric Fiselier06548ab2018-03-22 04:42:56 +000092#include <type_traits>
Howard Hinnantc51e1022010-05-11 19:42:16 +000093#include <cstddef>
Marshall Clow0a1e7502018-09-12 19:41:40 +000094#include <version>
Eric Fiselier279c3192016-09-06 21:25:27 +000095#ifdef _LIBCPP_NO_EXCEPTIONS
96#include <cstdlib>
97#endif
Howard Hinnantc51e1022010-05-11 19:42:16 +000098
Shoaib Meenaicfd19602017-10-09 19:25:17 +000099#if defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_NO_VCRUNTIME)
Eric Fiselierec3a1672017-02-10 08:57:35 +0000100#include <new.h>
101#endif
102
Howard Hinnantaaaa52b2011-10-17 20:05:10 +0000103#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
Howard Hinnantc51e1022010-05-11 19:42:16 +0000104#pragma GCC system_header
Howard Hinnantaaaa52b2011-10-17 20:05:10 +0000105#endif
Howard Hinnantc51e1022010-05-11 19:42:16 +0000106
Louis Dionne5e0eadd2018-08-01 02:08:59 +0000107#if !(defined(_LIBCPP_BUILDING_LIBRARY) || _LIBCPP_STD_VER >= 14 || \
Eric Fiselier162922f2016-10-14 06:46:30 +0000108 (defined(__cpp_sized_deallocation) && __cpp_sized_deallocation >= 201309))
109# define _LIBCPP_HAS_NO_SIZED_DEALLOCATION
110#endif
111
Eric Fiselier06548ab2018-03-22 04:42:56 +0000112#if !__has_builtin(__builtin_operator_new) || \
113 __has_builtin(__builtin_operator_new) < 201802L || \
114 defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION) || \
115 !defined(__cpp_aligned_new) || __cpp_aligned_new < 201606
116#define _LIBCPP_HAS_NO_BUILTIN_ALIGNED_OPERATOR_NEW_DELETE
117#endif
118
Howard Hinnantc51e1022010-05-11 19:42:16 +0000119namespace std // purposefully not using versioning namespace
120{
121
Shoaib Meenaicfd19602017-10-09 19:25:17 +0000122#if !defined(_LIBCPP_ABI_MICROSOFT) || defined(_LIBCPP_NO_VCRUNTIME)
Eric Fiselierec3a1672017-02-10 08:57:35 +0000123struct _LIBCPP_TYPE_VIS nothrow_t {};
124extern _LIBCPP_FUNC_VIS const nothrow_t nothrow;
125
Howard Hinnantc51e1022010-05-11 19:42:16 +0000126class _LIBCPP_EXCEPTION_ABI bad_alloc
127 : public exception
128{
129public:
Howard Hinnant1bc52cf2011-05-26 18:23:59 +0000130 bad_alloc() _NOEXCEPT;
131 virtual ~bad_alloc() _NOEXCEPT;
132 virtual const char* what() const _NOEXCEPT;
Howard Hinnantc51e1022010-05-11 19:42:16 +0000133};
134
135class _LIBCPP_EXCEPTION_ABI bad_array_new_length
136 : public bad_alloc
137{
138public:
Howard Hinnant1bc52cf2011-05-26 18:23:59 +0000139 bad_array_new_length() _NOEXCEPT;
140 virtual ~bad_array_new_length() _NOEXCEPT;
141 virtual const char* what() const _NOEXCEPT;
Howard Hinnantc51e1022010-05-11 19:42:16 +0000142};
143
Eric Fiselierec3a1672017-02-10 08:57:35 +0000144typedef void (*new_handler)();
145_LIBCPP_FUNC_VIS new_handler set_new_handler(new_handler) _NOEXCEPT;
146_LIBCPP_FUNC_VIS new_handler get_new_handler() _NOEXCEPT;
147
Shoaib Meenaicfd19602017-10-09 19:25:17 +0000148#endif // !_LIBCPP_ABI_MICROSOFT || _LIBCPP_NO_VCRUNTIME
Eric Fiselierec3a1672017-02-10 08:57:35 +0000149
Marshall Clow8fea1612016-08-25 15:09:01 +0000150_LIBCPP_NORETURN _LIBCPP_FUNC_VIS void __throw_bad_alloc(); // not in C++ spec
151
Eric Fiselierec3a1672017-02-10 08:57:35 +0000152#if defined(_LIBCPP_BUILDING_LIBRARY) || (_LIBCPP_STD_VER > 11)
Howard Hinnant4582a2b2013-11-07 17:15:51 +0000153
Mehdi Amini228053d2017-05-04 17:08:54 +0000154class _LIBCPP_EXCEPTION_ABI _LIBCPP_AVAILABILITY_BAD_ARRAY_LENGTH
155 bad_array_length : public bad_alloc {
Marshall Clow3bf77132013-09-11 01:38:42 +0000156public:
157 bad_array_length() _NOEXCEPT;
158 virtual ~bad_array_length() _NOEXCEPT;
159 virtual const char* what() const _NOEXCEPT;
160};
Howard Hinnant4582a2b2013-11-07 17:15:51 +0000161
162#define _LIBCPP_BAD_ARRAY_LENGTH_DEFINED
163
Louis Dionne5e0eadd2018-08-01 02:08:59 +0000164#endif // defined(_LIBCPP_BUILDING_LIBRARY) || (_LIBCPP_STD_VER > 11)
Marshall Clow3bf77132013-09-11 01:38:42 +0000165
Eric Fiseliere67336f2018-02-11 22:00:19 +0000166#if !defined(_LIBCPP_ABI_MICROSOFT) || defined(_LIBCPP_NO_VCRUNTIME)
Eric Fiselier9bb114e2017-01-21 14:42:44 +0000167#if !defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION) || _LIBCPP_STD_VER > 14
Eric Fiselier162922f2016-10-14 06:46:30 +0000168#ifndef _LIBCPP_CXX03_LANG
169enum class _LIBCPP_ENUM_VIS align_val_t : size_t { };
170#else
171enum align_val_t { __zero = 0, __max = (size_t)-1 };
172#endif
173#endif
Eric Fiseliere67336f2018-02-11 22:00:19 +0000174#endif
Eric Fiselier162922f2016-10-14 06:46:30 +0000175
Howard Hinnantc51e1022010-05-11 19:42:16 +0000176} // std
177
Eric Fiselier499a0a52017-01-02 23:27:42 +0000178#if defined(_LIBCPP_CXX03_LANG)
Eric Fiselier162922f2016-10-14 06:46:30 +0000179#define _THROW_BAD_ALLOC throw(std::bad_alloc)
180#else
181#define _THROW_BAD_ALLOC
Howard Hinnant1bc52cf2011-05-26 18:23:59 +0000182#endif
Eric Fiselier162922f2016-10-14 06:46:30 +0000183
Shoaib Meenaicfd19602017-10-09 19:25:17 +0000184#if !defined(_LIBCPP_ABI_MICROSOFT) || defined(_LIBCPP_NO_VCRUNTIME)
Eric Fiselierec3a1672017-02-10 08:57:35 +0000185
Marshall Clowbe8b84d2017-12-04 23:03:42 +0000186_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new(std::size_t __sz) _THROW_BAD_ALLOC;
187_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new(std::size_t __sz, const std::nothrow_t&) _NOEXCEPT _NOALIAS;
Shoaib Meenai2d71db42016-11-16 22:18:10 +0000188_LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete(void* __p) _NOEXCEPT;
189_LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete(void* __p, const std::nothrow_t&) _NOEXCEPT;
Eric Fiselier162922f2016-10-14 06:46:30 +0000190#ifndef _LIBCPP_HAS_NO_SIZED_DEALLOCATION
Mehdi Amini228053d2017-05-04 17:08:54 +0000191_LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE void operator delete(void* __p, std::size_t __sz) _NOEXCEPT;
Larisse Voufoa744a7e2015-02-20 06:13:05 +0000192#endif
Howard Hinnanta37d3cf2013-08-12 18:38:34 +0000193
Marshall Clowbe8b84d2017-12-04 23:03:42 +0000194_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new[](std::size_t __sz) _THROW_BAD_ALLOC;
195_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new[](std::size_t __sz, const std::nothrow_t&) _NOEXCEPT _NOALIAS;
Shoaib Meenai2d71db42016-11-16 22:18:10 +0000196_LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete[](void* __p) _NOEXCEPT;
197_LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete[](void* __p, const std::nothrow_t&) _NOEXCEPT;
Shoaib Meenaia2ee1d42016-11-18 04:31:09 +0000198#ifndef _LIBCPP_HAS_NO_SIZED_DEALLOCATION
Mehdi Amini228053d2017-05-04 17:08:54 +0000199_LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE void operator delete[](void* __p, std::size_t __sz) _NOEXCEPT;
Larisse Voufoa744a7e2015-02-20 06:13:05 +0000200#endif
Howard Hinnanta37d3cf2013-08-12 18:38:34 +0000201
Eric Fiselier162922f2016-10-14 06:46:30 +0000202#ifndef _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
Marshall Clowbe8b84d2017-12-04 23:03:42 +0000203_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new(std::size_t __sz, std::align_val_t) _THROW_BAD_ALLOC;
204_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new(std::size_t __sz, std::align_val_t, const std::nothrow_t&) _NOEXCEPT _NOALIAS;
Akira Hatanaka8c77d152017-06-30 18:50:23 +0000205_LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete(void* __p, std::align_val_t) _NOEXCEPT;
206_LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete(void* __p, std::align_val_t, const std::nothrow_t&) _NOEXCEPT;
Eric Fiselier162922f2016-10-14 06:46:30 +0000207#ifndef _LIBCPP_HAS_NO_SIZED_DEALLOCATION
Akira Hatanaka8c77d152017-06-30 18:50:23 +0000208_LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE void operator delete(void* __p, std::size_t __sz, std::align_val_t) _NOEXCEPT;
Eric Fiselier162922f2016-10-14 06:46:30 +0000209#endif
210
Marshall Clowbe8b84d2017-12-04 23:03:42 +0000211_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new[](std::size_t __sz, std::align_val_t) _THROW_BAD_ALLOC;
212_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new[](std::size_t __sz, std::align_val_t, const std::nothrow_t&) _NOEXCEPT _NOALIAS;
Akira Hatanaka8c77d152017-06-30 18:50:23 +0000213_LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete[](void* __p, std::align_val_t) _NOEXCEPT;
214_LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete[](void* __p, std::align_val_t, const std::nothrow_t&) _NOEXCEPT;
Eric Fiselier162922f2016-10-14 06:46:30 +0000215#ifndef _LIBCPP_HAS_NO_SIZED_DEALLOCATION
Akira Hatanaka8c77d152017-06-30 18:50:23 +0000216_LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE void operator delete[](void* __p, std::size_t __sz, std::align_val_t) _NOEXCEPT;
Eric Fiselier162922f2016-10-14 06:46:30 +0000217#endif
218#endif
219
Marshall Clowbe8b84d2017-12-04 23:03:42 +0000220_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_INLINE_VISIBILITY void* operator new (std::size_t, void* __p) _NOEXCEPT {return __p;}
221_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_INLINE_VISIBILITY void* operator new[](std::size_t, void* __p) _NOEXCEPT {return __p;}
Howard Hinnantb8a8ca22013-10-04 22:09:00 +0000222inline _LIBCPP_INLINE_VISIBILITY void operator delete (void*, void*) _NOEXCEPT {}
223inline _LIBCPP_INLINE_VISIBILITY void operator delete[](void*, void*) _NOEXCEPT {}
Howard Hinnantc51e1022010-05-11 19:42:16 +0000224
Shoaib Meenaicfd19602017-10-09 19:25:17 +0000225#endif // !_LIBCPP_ABI_MICROSOFT || _LIBCPP_NO_VCRUNTIME
Eric Fiselierec3a1672017-02-10 08:57:35 +0000226
Richard Smith1f1c1472014-06-04 19:54:15 +0000227_LIBCPP_BEGIN_NAMESPACE_STD
228
Eric Fiselier06548ab2018-03-22 04:42:56 +0000229_LIBCPP_CONSTEXPR inline _LIBCPP_INLINE_VISIBILITY bool __is_overaligned_for_new(size_t __align) _NOEXCEPT {
230#ifdef __STDCPP_DEFAULT_NEW_ALIGNMENT__
231 return __align > __STDCPP_DEFAULT_NEW_ALIGNMENT__;
232#else
233 return __align > alignment_of<max_align_t>::value;
234#endif
235}
236
237inline _LIBCPP_INLINE_VISIBILITY void *__libcpp_allocate(size_t __size, size_t __align) {
238#ifndef _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
239 if (__is_overaligned_for_new(__align)) {
240 const align_val_t __align_val = static_cast<align_val_t>(__align);
241# ifdef _LIBCPP_HAS_NO_BUILTIN_ALIGNED_OPERATOR_NEW_DELETE
242 return ::operator new(__size, __align_val);
243# else
244 return __builtin_operator_new(__size, __align_val);
245# endif
246 }
247#else
248 ((void)__align);
249#endif
Richard Smith1f1c1472014-06-04 19:54:15 +0000250#ifdef _LIBCPP_HAS_NO_BUILTIN_OPERATOR_NEW_DELETE
251 return ::operator new(__size);
252#else
253 return __builtin_operator_new(__size);
254#endif
255}
256
Eric Fiselier06548ab2018-03-22 04:42:56 +0000257inline _LIBCPP_INLINE_VISIBILITY void __libcpp_deallocate(void* __ptr, size_t __align) {
258#ifndef _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
259 if (__is_overaligned_for_new(__align)) {
260 const align_val_t __align_val = static_cast<align_val_t>(__align);
261# ifdef _LIBCPP_HAS_NO_BUILTIN_ALIGNED_OPERATOR_NEW_DELETE
262 return ::operator delete(__ptr, __align_val);
263# else
264 return __builtin_operator_delete(__ptr, __align_val);
265# endif
266 }
Richard Smith1f1c1472014-06-04 19:54:15 +0000267#else
Eric Fiselier06548ab2018-03-22 04:42:56 +0000268 ((void)__align);
269#endif
270#ifdef _LIBCPP_HAS_NO_BUILTIN_OPERATOR_NEW_DELETE
271 return ::operator delete(__ptr);
272#else
273 return __builtin_operator_delete(__ptr);
Richard Smith1f1c1472014-06-04 19:54:15 +0000274#endif
275}
276
Marshall Clow8fea1612016-08-25 15:09:01 +0000277#ifdef _LIBCPP_BAD_ARRAY_LENGTH_DEFINED
Louis Dionne16fe2952018-07-11 23:14:33 +0000278_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
Mehdi Amini228053d2017-05-04 17:08:54 +0000279#ifndef _LIBCPP_NO_EXCEPTIONS
280_LIBCPP_AVAILABILITY_BAD_ARRAY_LENGTH
281#endif
Marshall Clow8fea1612016-08-25 15:09:01 +0000282void __throw_bad_array_length()
283{
284#ifndef _LIBCPP_NO_EXCEPTIONS
285 throw bad_array_length();
286#else
Louis Dionne44bcff92018-08-03 22:36:53 +0000287 _VSTD::abort();
Marshall Clow8fea1612016-08-25 15:09:01 +0000288#endif
289}
290#endif
291
Marshall Clowdf5a11f2017-11-22 19:49:03 +0000292template <class _Tp>
Louis Dionne44bcff92018-08-03 22:36:53 +0000293_LIBCPP_NODISCARD_AFTER_CXX17 inline
Marshall Clowdf5a11f2017-11-22 19:49:03 +0000294_LIBCPP_CONSTEXPR _Tp* __launder(_Tp* __p) _NOEXCEPT
295{
296 static_assert (!(is_function<_Tp>::value), "can't launder functions" );
297 static_assert (!(is_same<void, typename remove_cv<_Tp>::type>::value), "can't launder cv-void" );
298#ifdef _LIBCPP_COMPILER_HAS_BUILTIN_LAUNDER
299 return __builtin_launder(__p);
300#else
301 return __p;
302#endif
303}
304
305
306#if _LIBCPP_STD_VER > 14
307template <class _Tp>
308_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_INLINE_VISIBILITY
309constexpr _Tp* launder(_Tp* __p) noexcept
310{
Marshall Clow6ac349c2017-11-23 01:25:03 +0000311 return _VSTD::__launder(__p);
Marshall Clowdf5a11f2017-11-22 19:49:03 +0000312}
313#endif
314
Richard Smith1f1c1472014-06-04 19:54:15 +0000315_LIBCPP_END_NAMESPACE_STD
316
Howard Hinnantc51e1022010-05-11 19:42:16 +0000317#endif // _LIBCPP_NEW