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1 : // -*- C++ -*-
2 : //===----------------------------------------------------------------------===//
3 : //
4 : // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 : // See https://llvm.org/LICENSE.txt for license information.
6 : // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 : //
8 : //===----------------------------------------------------------------------===//
9 :
10 : #ifndef _LIBCPP___MEMORY_ALLOCATOR_H
11 : #define _LIBCPP___MEMORY_ALLOCATOR_H
12 :
13 : #include <__config>
14 : #include <__memory/allocate_at_least.h>
15 : #include <__memory/allocator_traits.h>
16 : #include <__type_traits/is_constant_evaluated.h>
17 : #include <__type_traits/is_same.h>
18 : #include <__type_traits/is_void.h>
19 : #include <__type_traits/is_volatile.h>
20 : #include <__utility/forward.h>
21 : #include <cstddef>
22 : #include <new>
23 : #include <stdexcept>
24 :
25 : #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
26 : # pragma GCC system_header
27 : #endif
28 :
29 : _LIBCPP_BEGIN_NAMESPACE_STD
30 :
31 : template <class _Tp> class allocator;
32 :
33 : #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_VOID_SPECIALIZATION)
34 : // These specializations shouldn't be marked _LIBCPP_DEPRECATED_IN_CXX17.
35 : // Specializing allocator<void> is deprecated, but not using it.
36 : template <>
37 : class _LIBCPP_TEMPLATE_VIS allocator<void>
38 : {
39 : #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS)
40 : public:
41 : _LIBCPP_DEPRECATED_IN_CXX17 typedef void* pointer;
42 : _LIBCPP_DEPRECATED_IN_CXX17 typedef const void* const_pointer;
43 : _LIBCPP_DEPRECATED_IN_CXX17 typedef void value_type;
44 :
45 : template <class _Up> struct _LIBCPP_DEPRECATED_IN_CXX17 rebind {typedef allocator<_Up> other;};
46 : #endif
47 : };
48 :
49 : template <>
50 : class _LIBCPP_TEMPLATE_VIS allocator<const void>
51 : {
52 : #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS)
53 : public:
54 : _LIBCPP_DEPRECATED_IN_CXX17 typedef const void* pointer;
55 : _LIBCPP_DEPRECATED_IN_CXX17 typedef const void* const_pointer;
56 : _LIBCPP_DEPRECATED_IN_CXX17 typedef const void value_type;
57 :
58 : template <class _Up> struct _LIBCPP_DEPRECATED_IN_CXX17 rebind {typedef allocator<_Up> other;};
59 : #endif
60 : };
61 : #endif
62 :
63 : // This class provides a non-trivial default constructor to the class that derives from it
64 : // if the condition is satisfied.
65 : //
66 : // The second template parameter exists to allow giving a unique type to __non_trivial_if,
67 : // which makes it possible to avoid breaking the ABI when making this a base class of an
68 : // existing class. Without that, imagine we have classes D1 and D2, both of which used to
69 : // have no base classes, but which now derive from __non_trivial_if. The layout of a class
70 : // that inherits from both D1 and D2 will change because the two __non_trivial_if base
71 : // classes are not allowed to share the same address.
72 : //
73 : // By making those __non_trivial_if base classes unique, we work around this problem and
74 : // it is safe to start deriving from __non_trivial_if in existing classes.
75 : template <bool _Cond, class _Unique>
76 : struct __non_trivial_if { };
77 :
78 : template <class _Unique>
79 : struct __non_trivial_if<true, _Unique> {
80 : _LIBCPP_INLINE_VISIBILITY
81 11624 : _LIBCPP_CONSTEXPR __non_trivial_if() _NOEXCEPT { }
82 : };
83 :
84 : // allocator
85 : //
86 : // Note: For ABI compatibility between C++20 and previous standards, we make
87 : // allocator<void> trivial in C++20.
88 :
89 : template <class _Tp>
90 : class _LIBCPP_TEMPLATE_VIS allocator
91 : : private __non_trivial_if<!is_void<_Tp>::value, allocator<_Tp> >
92 : {
93 : static_assert(!is_volatile<_Tp>::value, "std::allocator does not support volatile types");
94 : public:
95 : typedef size_t size_type;
96 : typedef ptrdiff_t difference_type;
97 : typedef _Tp value_type;
98 : typedef true_type propagate_on_container_move_assignment;
99 : typedef true_type is_always_equal;
100 :
101 : _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
102 14088 : allocator() _NOEXCEPT = default;
103 :
104 : template <class _Up>
105 : _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
106 : allocator(const allocator<_Up>&) _NOEXCEPT { }
107 :
108 : _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
109 111 : _Tp* allocate(size_t __n) {
110 111 : if (__n > allocator_traits<allocator>::max_size(*this))
111 0 : __throw_bad_array_new_length();
112 111 : if (__libcpp_is_constant_evaluated()) {
113 0 : return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp)));
114 : } else {
115 111 : return static_cast<_Tp*>(_VSTD::__libcpp_allocate(__n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp)));
116 : }
117 111 : }
118 :
119 : #if _LIBCPP_STD_VER > 20
120 : [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr
121 : allocation_result<_Tp*> allocate_at_least(size_t __n) {
122 : return {allocate(__n), __n};
123 : }
124 : #endif
125 :
126 : _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
127 33 : void deallocate(_Tp* __p, size_t __n) _NOEXCEPT {
128 33 : if (__libcpp_is_constant_evaluated()) {
129 0 : ::operator delete(__p);
130 0 : } else {
131 33 : _VSTD::__libcpp_deallocate((void*)__p, __n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp));
132 : }
133 33 : }
134 :
135 : // C++20 Removed members
136 : #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS)
137 : _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp* pointer;
138 : _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp* const_pointer;
139 : _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp& reference;
140 : _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp& const_reference;
141 :
142 : template <class _Up>
143 : struct _LIBCPP_DEPRECATED_IN_CXX17 rebind {
144 : typedef allocator<_Up> other;
145 : };
146 :
147 : _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY
148 : pointer address(reference __x) const _NOEXCEPT {
149 : return _VSTD::addressof(__x);
150 : }
151 : _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY
152 : const_pointer address(const_reference __x) const _NOEXCEPT {
153 : return _VSTD::addressof(__x);
154 : }
155 :
156 : _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_DEPRECATED_IN_CXX17
157 : _Tp* allocate(size_t __n, const void*) {
158 : return allocate(__n);
159 : }
160 :
161 36998 : _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY size_type max_size() const _NOEXCEPT {
162 36998 : return size_type(~0) / sizeof(_Tp);
163 : }
164 :
165 : template <class _Up, class... _Args>
166 : _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY
167 2983 : void construct(_Up* __p, _Args&&... __args) {
168 2983 : ::new ((void*)__p) _Up(_VSTD::forward<_Args>(__args)...);
169 2983 : }
170 :
171 : _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY
172 3055 : void destroy(pointer __p) {
173 3055 : __p->~_Tp();
174 3055 : }
175 : #endif
176 : };
177 :
178 : template <class _Tp>
179 : class _LIBCPP_TEMPLATE_VIS allocator<const _Tp>
180 : : private __non_trivial_if<!is_void<_Tp>::value, allocator<const _Tp> >
181 : {
182 : static_assert(!is_volatile<_Tp>::value, "std::allocator does not support volatile types");
183 : public:
184 : typedef size_t size_type;
185 : typedef ptrdiff_t difference_type;
186 : typedef const _Tp value_type;
187 : typedef true_type propagate_on_container_move_assignment;
188 : typedef true_type is_always_equal;
189 :
190 : _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
191 : allocator() _NOEXCEPT = default;
192 :
193 : template <class _Up>
194 : _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
195 : allocator(const allocator<_Up>&) _NOEXCEPT { }
196 :
197 : _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
198 : const _Tp* allocate(size_t __n) {
199 : if (__n > allocator_traits<allocator>::max_size(*this))
200 : __throw_bad_array_new_length();
201 : if (__libcpp_is_constant_evaluated()) {
202 : return static_cast<const _Tp*>(::operator new(__n * sizeof(_Tp)));
203 : } else {
204 : return static_cast<const _Tp*>(_VSTD::__libcpp_allocate(__n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp)));
205 : }
206 : }
207 :
208 : #if _LIBCPP_STD_VER > 20
209 : [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr
210 : allocation_result<const _Tp*> allocate_at_least(size_t __n) {
211 : return {allocate(__n), __n};
212 : }
213 : #endif
214 :
215 : _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
216 : void deallocate(const _Tp* __p, size_t __n) {
217 : if (__libcpp_is_constant_evaluated()) {
218 : ::operator delete(const_cast<_Tp*>(__p));
219 : } else {
220 : _VSTD::__libcpp_deallocate((void*) const_cast<_Tp *>(__p), __n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp));
221 : }
222 : }
223 :
224 : // C++20 Removed members
225 : #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS)
226 : _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp* pointer;
227 : _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp* const_pointer;
228 : _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp& reference;
229 : _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp& const_reference;
230 :
231 : template <class _Up>
232 : struct _LIBCPP_DEPRECATED_IN_CXX17 rebind {
233 : typedef allocator<_Up> other;
234 : };
235 :
236 : _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY
237 : const_pointer address(const_reference __x) const _NOEXCEPT {
238 : return _VSTD::addressof(__x);
239 : }
240 :
241 : _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_DEPRECATED_IN_CXX17
242 : const _Tp* allocate(size_t __n, const void*) {
243 : return allocate(__n);
244 : }
245 :
246 : _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY size_type max_size() const _NOEXCEPT {
247 : return size_type(~0) / sizeof(_Tp);
248 : }
249 :
250 : template <class _Up, class... _Args>
251 : _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY
252 : void construct(_Up* __p, _Args&&... __args) {
253 : ::new ((void*)__p) _Up(_VSTD::forward<_Args>(__args)...);
254 : }
255 :
256 : _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY
257 : void destroy(pointer __p) {
258 : __p->~_Tp();
259 : }
260 : #endif
261 : };
262 :
263 : template <class _Tp, class _Up>
264 : inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
265 : bool operator==(const allocator<_Tp>&, const allocator<_Up>&) _NOEXCEPT {return true;}
266 :
267 : template <class _Tp, class _Up>
268 : inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
269 : bool operator!=(const allocator<_Tp>&, const allocator<_Up>&) _NOEXCEPT {return false;}
270 :
271 : _LIBCPP_END_NAMESPACE_STD
272 :
273 : #endif // _LIBCPP___MEMORY_ALLOCATOR_H
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