1// The -*- C++ -*- dynamic memory management header.
2
3// Copyright (C) 1994-2024 Free Software Foundation, Inc.
4
5// This file is part of GCC.
6//
7// GCC is free software; you can redistribute it and/or modify
8// it under the terms of the GNU General Public License as published by
9// the Free Software Foundation; either version 3, or (at your option)
10// any later version.
11//
12// GCC is distributed in the hope that it will be useful,
13// but WITHOUT ANY WARRANTY; without even the implied warranty of
14// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15// GNU General Public License for more details.
16//
17// Under Section 7 of GPL version 3, you are granted additional
18// permissions described in the GCC Runtime Library Exception, version
19// 3.1, as published by the Free Software Foundation.
20
21// You should have received a copy of the GNU General Public License and
22// a copy of the GCC Runtime Library Exception along with this program;
23// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24// <http://www.gnu.org/licenses/>.
25
26/** @file new
27 * This is a Standard C++ Library header.
28 *
29 * The header @c new defines several functions to manage dynamic memory and
30 * handling memory allocation errors; see
31 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/dynamic_memory.html
32 * for more.
33 */
34
35#ifndef _NEW
36#define _NEW
37
38#pragma GCC system_header
39
40#include <bits/c++config.h>
41#include <bits/exception.h>
42
43#define __glibcxx_want_launder
44#define __glibcxx_want_hardware_interference_size
45#define __glibcxx_want_destroying_delete
46#include <bits/version.h>
47
48#pragma GCC visibility push(default)
49
50extern "C++" {
51
52namespace std
53{
54 /**
55 * @brief Exception possibly thrown by @c new.
56 * @ingroup exceptions
57 *
58 * @c bad_alloc (or classes derived from it) is used to report allocation
59 * errors from the throwing forms of @c new. */
60 class bad_alloc : public exception
61 {
62 public:
63 bad_alloc() throw() { }
64
65#if __cplusplus >= 201103L
66 bad_alloc(const bad_alloc&) = default;
67 bad_alloc& operator=(const bad_alloc&) = default;
68#endif
69
70 // This declaration is not useless:
71 // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
72 virtual ~bad_alloc() throw();
73
74 // See comment in eh_exception.cc.
75 virtual const char* what() const throw();
76 };
77
78#if __cplusplus >= 201103L
79 class bad_array_new_length : public bad_alloc
80 {
81 public:
82 bad_array_new_length() throw() { }
83
84 // This declaration is not useless:
85 // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
86 virtual ~bad_array_new_length() throw();
87
88 // See comment in eh_exception.cc.
89 virtual const char* what() const throw();
90 };
91#endif
92
93#if __cpp_aligned_new
94 enum class align_val_t: size_t {};
95#endif
96
97 struct nothrow_t
98 {
99#if __cplusplus >= 201103L
100 explicit nothrow_t() = default;
101#endif
102 };
103
104 extern const nothrow_t nothrow;
105
106 /** If you write your own error handler to be called by @c new, it must
107 * be of this type. */
108 typedef void (*new_handler)();
109
110 /// Takes a replacement handler as the argument, returns the
111 /// previous handler.
112 new_handler set_new_handler(new_handler) throw();
113
114#if __cplusplus >= 201103L
115 /// Return the current new handler.
116 new_handler get_new_handler() noexcept;
117#endif
118} // namespace std
119
120//@{
121/** These are replaceable signatures:
122 * - normal single new and delete (no arguments, throw @c bad_alloc on error)
123 * - normal array new and delete (same)
124 * - @c nothrow single new and delete (take a @c nothrow argument, return
125 * @c NULL on error)
126 * - @c nothrow array new and delete (same)
127 *
128 * Placement new and delete signatures (take a memory address argument,
129 * does nothing) may not be replaced by a user's program.
130*/
131_GLIBCXX_NODISCARD void* operator new(std::size_t) _GLIBCXX_THROW (std::bad_alloc)
132 __attribute__((__externally_visible__));
133_GLIBCXX_NODISCARD void* operator new[](std::size_t) _GLIBCXX_THROW (std::bad_alloc)
134 __attribute__((__externally_visible__));
135void operator delete(void*) _GLIBCXX_USE_NOEXCEPT
136 __attribute__((__externally_visible__));
137void operator delete[](void*) _GLIBCXX_USE_NOEXCEPT
138 __attribute__((__externally_visible__));
139#if __cpp_sized_deallocation
140void operator delete(void*, std::size_t) _GLIBCXX_USE_NOEXCEPT
141 __attribute__((__externally_visible__));
142void operator delete[](void*, std::size_t) _GLIBCXX_USE_NOEXCEPT
143 __attribute__((__externally_visible__));
144#endif
145_GLIBCXX_NODISCARD void* operator new(std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
146 __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
147_GLIBCXX_NODISCARD void* operator new[](std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
148 __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
149void operator delete(void*, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
150 __attribute__((__externally_visible__));
151void operator delete[](void*, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
152 __attribute__((__externally_visible__));
153#if __cpp_aligned_new
154_GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t)
155 __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
156_GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t, const std::nothrow_t&)
157 _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
158void operator delete(void*, std::align_val_t)
159 _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
160void operator delete(void*, std::align_val_t, const std::nothrow_t&)
161 _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
162_GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t)
163 __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
164_GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t, const std::nothrow_t&)
165 _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
166void operator delete[](void*, std::align_val_t)
167 _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
168void operator delete[](void*, std::align_val_t, const std::nothrow_t&)
169 _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
170#if __cpp_sized_deallocation
171void operator delete(void*, std::size_t, std::align_val_t)
172 _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
173void operator delete[](void*, std::size_t, std::align_val_t)
174 _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
175#endif // __cpp_sized_deallocation
176#endif // __cpp_aligned_new
177
178// Default placement versions of operator new.
179_GLIBCXX_NODISCARD inline void* operator new(std::size_t, void* __p) _GLIBCXX_USE_NOEXCEPT
180{ return __p; }
181_GLIBCXX_NODISCARD inline void* operator new[](std::size_t, void* __p) _GLIBCXX_USE_NOEXCEPT
182{ return __p; }
183
184// Default placement versions of operator delete.
185inline void operator delete (void*, void*) _GLIBCXX_USE_NOEXCEPT { }
186inline void operator delete[](void*, void*) _GLIBCXX_USE_NOEXCEPT { }
187//@}
188} // extern "C++"
189
190#if __cplusplus >= 201703L
191namespace std
192{
193#ifdef __cpp_lib_launder // C++ >= 17 && HAVE_BUILTIN_LAUNDER
194 /// Pointer optimization barrier [ptr.launder]
195 template<typename _Tp>
196 [[nodiscard]] constexpr _Tp*
197 launder(_Tp* __p) noexcept
198 { return __builtin_launder(__p); }
199
200 // The program is ill-formed if T is a function type or
201 // (possibly cv-qualified) void.
202
203 template<typename _Ret, typename... _Args _GLIBCXX_NOEXCEPT_PARM>
204 void launder(_Ret (*)(_Args...) _GLIBCXX_NOEXCEPT_QUAL) = delete;
205 template<typename _Ret, typename... _Args _GLIBCXX_NOEXCEPT_PARM>
206 void launder(_Ret (*)(_Args......) _GLIBCXX_NOEXCEPT_QUAL) = delete;
207
208 void launder(void*) = delete;
209 void launder(const void*) = delete;
210 void launder(volatile void*) = delete;
211 void launder(const volatile void*) = delete;
212#endif // __cpp_lib_launder
213
214#ifdef __cpp_lib_hardware_interference_size // C++ >= 17 && defined(gcc_dest_sz)
215 inline constexpr size_t hardware_destructive_interference_size = __GCC_DESTRUCTIVE_SIZE;
216 inline constexpr size_t hardware_constructive_interference_size = __GCC_CONSTRUCTIVE_SIZE;
217#endif // __cpp_lib_hardware_interference_size
218}
219#endif // C++17
220
221// Emitted despite the FTM potentially being undefined.
222#if __cplusplus > 201703L
223namespace std
224{
225 /// Tag type used to declare a class-specific operator delete that can
226 /// invoke the destructor before deallocating the memory.
227 struct destroying_delete_t
228 {
229 explicit destroying_delete_t() = default;
230 };
231 /// Tag variable of type destroying_delete_t.
232 inline constexpr destroying_delete_t destroying_delete{};
233}
234#endif // C++20
235
236#pragma GCC visibility pop
237
238#endif
239