1// The -*- C++ -*- dynamic memory management header.
2
3// Copyright (C) 1994-2019 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 *  http://gcc.gnu.org/onlinedocs/libstdc++/18_support/howto.html#4 for more.
32 */
33
34#ifndef _NEW
35#define _NEW
36
37#pragma GCC system_header
38
39#include <bits/c++config.h>
40#include <exception>
41
42#pragma GCC visibility push(default)
43
44extern "C++" {
45
46namespace std
47{
48  /**
49   *  @brief  Exception possibly thrown by @c new.
50   *  @ingroup exceptions
51   *
52   *  @c bad_alloc (or classes derived from it) is used to report allocation
53   *  errors from the throwing forms of @c new.  */
54  class bad_alloc : public exception
55  {
56  public:
57    bad_alloc() throw() { }
58
59#if __cplusplus >= 201103L
60    bad_alloc(const bad_alloc&) = default;
61    bad_alloc& operator=(const bad_alloc&) = default;
62#endif
63
64    // This declaration is not useless:
65    // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
66    virtual ~bad_alloc() throw();
67
68    // See comment in eh_exception.cc.
69    virtual const char* what() const throw();
70  };
71
72#if __cplusplus >= 201103L
73  class bad_array_new_length : public bad_alloc
74  {
75  public:
76    bad_array_new_length() throw() { }
77
78    // This declaration is not useless:
79    // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
80    virtual ~bad_array_new_length() throw();
81
82    // See comment in eh_exception.cc.
83    virtual const char* what() const throw();
84  };
85#endif
86
87#if __cpp_aligned_new
88  enum class align_val_t: size_t {};
89#endif
90
91  struct nothrow_t
92  {
93#if __cplusplus >= 201103L
94    explicit nothrow_t() = default;
95#endif
96  };
97
98  extern const nothrow_t nothrow;
99
100  /** If you write your own error handler to be called by @c new, it must
101   *  be of this type.  */
102  typedef void (*new_handler)();
103
104  /// Takes a replacement handler as the argument, returns the
105  /// previous handler.
106  new_handler set_new_handler(new_handler) throw();
107
108#if __cplusplus >= 201103L
109  /// Return the current new handler.
110  new_handler get_new_handler() noexcept;
111#endif
112} // namespace std
113
114//@{
115/** These are replaceable signatures:
116 *  - normal single new and delete (no arguments, throw @c bad_alloc on error)
117 *  - normal array new and delete (same)
118 *  - @c nothrow single new and delete (take a @c nothrow argument, return
119 *    @c NULL on error)
120 *  - @c nothrow array new and delete (same)
121 *
122 *  Placement new and delete signatures (take a memory address argument,
123 *  does nothing) may not be replaced by a user's program.
124*/
125_GLIBCXX_NODISCARD void* operator new(std::size_t) _GLIBCXX_THROW (std::bad_alloc)
126  __attribute__((__externally_visible__));
127_GLIBCXX_NODISCARD void* operator new[](std::size_t) _GLIBCXX_THROW (std::bad_alloc)
128  __attribute__((__externally_visible__));
129void operator delete(void*) _GLIBCXX_USE_NOEXCEPT
130  __attribute__((__externally_visible__));
131void operator delete[](void*) _GLIBCXX_USE_NOEXCEPT
132  __attribute__((__externally_visible__));
133#if __cpp_sized_deallocation
134void operator delete(void*, std::size_t) _GLIBCXX_USE_NOEXCEPT
135  __attribute__((__externally_visible__));
136void operator delete[](void*, std::size_t) _GLIBCXX_USE_NOEXCEPT
137  __attribute__((__externally_visible__));
138#endif
139_GLIBCXX_NODISCARD void* operator new(std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
140  __attribute__((__externally_visible__, __malloc__));
141_GLIBCXX_NODISCARD void* operator new[](std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
142  __attribute__((__externally_visible__, __malloc__));
143void operator delete(void*, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
144  __attribute__((__externally_visible__));
145void operator delete[](void*, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
146  __attribute__((__externally_visible__));
147#if __cpp_aligned_new
148_GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t)
149  __attribute__((__externally_visible__));
150_GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t, const std::nothrow_t&)
151  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__, __malloc__));
152void operator delete(void*, std::align_val_t)
153  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
154void operator delete(void*, std::align_val_t, const std::nothrow_t&)
155  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
156_GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t)
157  __attribute__((__externally_visible__));
158_GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t, const std::nothrow_t&)
159  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__, __malloc__));
160void operator delete[](void*, std::align_val_t)
161  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
162void operator delete[](void*, std::align_val_t, const std::nothrow_t&)
163  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
164#if __cpp_sized_deallocation
165void operator delete(void*, std::size_t, std::align_val_t)
166  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
167void operator delete[](void*, std::size_t, std::align_val_t)
168  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
169#endif // __cpp_sized_deallocation
170#endif // __cpp_aligned_new
171
172// Default placement versions of operator new.
173_GLIBCXX_NODISCARD inline void* operator new(std::size_t, void* __p) _GLIBCXX_USE_NOEXCEPT
174{ return __p; }
175_GLIBCXX_NODISCARD inline void* operator new[](std::size_t, void* __p) _GLIBCXX_USE_NOEXCEPT
176{ return __p; }
177
178// Default placement versions of operator delete.
179inline void operator delete  (void*, void*) _GLIBCXX_USE_NOEXCEPT { }
180inline void operator delete[](void*, void*) _GLIBCXX_USE_NOEXCEPT { }
181//@}
182} // extern "C++"
183
184#if __cplusplus >= 201703L
185#ifdef _GLIBCXX_HAVE_BUILTIN_LAUNDER
186namespace std
187{
188#define __cpp_lib_launder 201606
189  /// Pointer optimization barrier [ptr.launder]
190  template<typename _Tp>
191    [[nodiscard]] constexpr _Tp*
192    launder(_Tp* __p) noexcept
193    { return __builtin_launder(__p); }
194
195  // The program is ill-formed if T is a function type or
196  // (possibly cv-qualified) void.
197
198  template<typename _Ret, typename... _Args _GLIBCXX_NOEXCEPT_PARM>
199    void launder(_Ret (*)(_Args...) _GLIBCXX_NOEXCEPT_QUAL) = delete;
200  template<typename _Ret, typename... _Args _GLIBCXX_NOEXCEPT_PARM>
201    void launder(_Ret (*)(_Args......) _GLIBCXX_NOEXCEPT_QUAL) = delete;
202
203  void launder(void*) = delete;
204  void launder(const void*) = delete;
205  void launder(volatile void*) = delete;
206  void launder(const volatile void*) = delete;
207}
208#endif // _GLIBCXX_HAVE_BUILTIN_LAUNDER
209#endif // C++17
210
211#if __cplusplus > 201703L
212namespace std
213{
214  struct destroying_delete_t
215  {
216    explicit destroying_delete_t() = default;
217  };
218  inline constexpr destroying_delete_t destroying_delete{};
219}
220// Only define the feature test macro if the compiler supports the feature:
221#if __cpp_impl_destroying_delete
222# define __cpp_lib_destroying_delete 201806L
223#endif
224#endif // C++20
225
226#pragma GCC visibility pop
227
228#endif
229