1// The -*- C++ -*- dynamic memory management header.
2
3// Copyright (C) 1994-2020 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 <exception>
42
43#pragma GCC visibility push(default)
44
45extern "C++" {
46
47namespace std
48{
49  /**
50   *  @brief  Exception possibly thrown by @c new.
51   *  @ingroup exceptions
52   *
53   *  @c bad_alloc (or classes derived from it) is used to report allocation
54   *  errors from the throwing forms of @c new.  */
55  class bad_alloc : public exception
56  {
57  public:
58    bad_alloc() throw() { }
59
60#if __cplusplus >= 201103L
61    bad_alloc(const bad_alloc&) = default;
62    bad_alloc& operator=(const bad_alloc&) = default;
63#endif
64
65    // This declaration is not useless:
66    // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
67    virtual ~bad_alloc() throw();
68
69    // See comment in eh_exception.cc.
70    virtual const char* what() const throw();
71  };
72
73#if __cplusplus >= 201103L
74  class bad_array_new_length : public bad_alloc
75  {
76  public:
77    bad_array_new_length() throw() { }
78
79    // This declaration is not useless:
80    // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
81    virtual ~bad_array_new_length() throw();
82
83    // See comment in eh_exception.cc.
84    virtual const char* what() const throw();
85  };
86#endif
87
88#if __cpp_aligned_new
89  enum class align_val_t: size_t {};
90#endif
91
92  struct nothrow_t
93  {
94#if __cplusplus >= 201103L
95    explicit nothrow_t() = default;
96#endif
97  };
98
99  extern const nothrow_t nothrow;
100
101  /** If you write your own error handler to be called by @c new, it must
102   *  be of this type.  */
103  typedef void (*new_handler)();
104
105  /// Takes a replacement handler as the argument, returns the
106  /// previous handler.
107  new_handler set_new_handler(new_handler) throw();
108
109#if __cplusplus >= 201103L
110  /// Return the current new handler.
111  new_handler get_new_handler() noexcept;
112#endif
113} // namespace std
114
115//@{
116/** These are replaceable signatures:
117 *  - normal single new and delete (no arguments, throw @c bad_alloc on error)
118 *  - normal array new and delete (same)
119 *  - @c nothrow single new and delete (take a @c nothrow argument, return
120 *    @c NULL on error)
121 *  - @c nothrow array new and delete (same)
122 *
123 *  Placement new and delete signatures (take a memory address argument,
124 *  does nothing) may not be replaced by a user's program.
125*/
126_GLIBCXX_NODISCARD void* operator new(std::size_t) _GLIBCXX_THROW (std::bad_alloc)
127  __attribute__((__externally_visible__));
128_GLIBCXX_NODISCARD void* operator new[](std::size_t) _GLIBCXX_THROW (std::bad_alloc)
129  __attribute__((__externally_visible__));
130void operator delete(void*) _GLIBCXX_USE_NOEXCEPT
131  __attribute__((__externally_visible__));
132void operator delete[](void*) _GLIBCXX_USE_NOEXCEPT
133  __attribute__((__externally_visible__));
134#if __cpp_sized_deallocation
135void operator delete(void*, std::size_t) _GLIBCXX_USE_NOEXCEPT
136  __attribute__((__externally_visible__));
137void operator delete[](void*, std::size_t) _GLIBCXX_USE_NOEXCEPT
138  __attribute__((__externally_visible__));
139#endif
140_GLIBCXX_NODISCARD void* operator new(std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
141  __attribute__((__externally_visible__, __malloc__));
142_GLIBCXX_NODISCARD void* operator new[](std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
143  __attribute__((__externally_visible__, __malloc__));
144void operator delete(void*, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
145  __attribute__((__externally_visible__));
146void operator delete[](void*, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
147  __attribute__((__externally_visible__));
148#if __cpp_aligned_new
149_GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t)
150  __attribute__((__externally_visible__));
151_GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t, const std::nothrow_t&)
152  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__, __malloc__));
153void operator delete(void*, std::align_val_t)
154  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
155void operator delete(void*, std::align_val_t, const std::nothrow_t&)
156  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
157_GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t)
158  __attribute__((__externally_visible__));
159_GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t, const std::nothrow_t&)
160  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__, __malloc__));
161void operator delete[](void*, std::align_val_t)
162  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
163void operator delete[](void*, std::align_val_t, const std::nothrow_t&)
164  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
165#if __cpp_sized_deallocation
166void operator delete(void*, std::size_t, std::align_val_t)
167  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
168void operator delete[](void*, std::size_t, std::align_val_t)
169  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
170#endif // __cpp_sized_deallocation
171#endif // __cpp_aligned_new
172
173// Default placement versions of operator new.
174_GLIBCXX_NODISCARD inline void* operator new(std::size_t, void* __p) _GLIBCXX_USE_NOEXCEPT
175{ return __p; }
176_GLIBCXX_NODISCARD inline void* operator new[](std::size_t, void* __p) _GLIBCXX_USE_NOEXCEPT
177{ return __p; }
178
179// Default placement versions of operator delete.
180inline void operator delete  (void*, void*) _GLIBCXX_USE_NOEXCEPT { }
181inline void operator delete[](void*, void*) _GLIBCXX_USE_NOEXCEPT { }
182//@}
183} // extern "C++"
184
185#if __cplusplus >= 201703L
186#ifdef _GLIBCXX_HAVE_BUILTIN_LAUNDER
187namespace std
188{
189#define __cpp_lib_launder 201606
190  /// Pointer optimization barrier [ptr.launder]
191  template<typename _Tp>
192    [[nodiscard]] constexpr _Tp*
193    launder(_Tp* __p) noexcept
194    { return __builtin_launder(__p); }
195
196  // The program is ill-formed if T is a function type or
197  // (possibly cv-qualified) void.
198
199  template<typename _Ret, typename... _Args _GLIBCXX_NOEXCEPT_PARM>
200    void launder(_Ret (*)(_Args...) _GLIBCXX_NOEXCEPT_QUAL) = delete;
201  template<typename _Ret, typename... _Args _GLIBCXX_NOEXCEPT_PARM>
202    void launder(_Ret (*)(_Args......) _GLIBCXX_NOEXCEPT_QUAL) = delete;
203
204  void launder(void*) = delete;
205  void launder(const void*) = delete;
206  void launder(volatile void*) = delete;
207  void launder(const volatile void*) = delete;
208}
209#endif // _GLIBCXX_HAVE_BUILTIN_LAUNDER
210#endif // C++17
211
212#if __cplusplus > 201703L
213namespace std
214{
215  /// Tag type used to declare a class-specific operator delete that can
216  /// invoke the destructor before deallocating the memory.
217  struct destroying_delete_t
218  {
219    explicit destroying_delete_t() = default;
220  };
221  /// Tag variable of type destroying_delete_t.
222  inline constexpr destroying_delete_t destroying_delete{};
223}
224// Only define the feature test macro if the compiler supports the feature:
225#if __cpp_impl_destroying_delete
226# define __cpp_lib_destroying_delete 201806L
227#endif
228#endif // C++20
229
230#pragma GCC visibility pop
231
232#endif
233