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 <__utility/forward.h> 17 #include <cstddef> 18 #include <new> 19 #include <stdexcept> 20 #include <type_traits> 21 22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 23 # pragma GCC system_header 24 #endif 25 26 _LIBCPP_BEGIN_NAMESPACE_STD 27 28 template <class _Tp> class allocator; 29 30 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_VOID_SPECIALIZATION) 31 // These specializations shouldn't be marked _LIBCPP_DEPRECATED_IN_CXX17. 32 // Specializing allocator<void> is deprecated, but not using it. 33 template <> 34 class _LIBCPP_TEMPLATE_VIS allocator<void> 35 { 36 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS) 37 public: 38 _LIBCPP_DEPRECATED_IN_CXX17 typedef void* pointer; 39 _LIBCPP_DEPRECATED_IN_CXX17 typedef const void* const_pointer; 40 _LIBCPP_DEPRECATED_IN_CXX17 typedef void value_type; 41 42 template <class _Up> struct _LIBCPP_DEPRECATED_IN_CXX17 rebind {typedef allocator<_Up> other;}; 43 #endif 44 }; 45 46 template <> 47 class _LIBCPP_TEMPLATE_VIS allocator<const void> 48 { 49 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS) 50 public: 51 _LIBCPP_DEPRECATED_IN_CXX17 typedef const void* pointer; 52 _LIBCPP_DEPRECATED_IN_CXX17 typedef const void* const_pointer; 53 _LIBCPP_DEPRECATED_IN_CXX17 typedef const void value_type; 54 55 template <class _Up> struct _LIBCPP_DEPRECATED_IN_CXX17 rebind {typedef allocator<_Up> other;}; 56 #endif 57 }; 58 #endif 59 60 // This class provides a non-trivial default constructor to the class that derives from it 61 // if the condition is satisfied. 62 // 63 // The second template parameter exists to allow giving a unique type to __non_trivial_if, 64 // which makes it possible to avoid breaking the ABI when making this a base class of an 65 // existing class. Without that, imagine we have classes D1 and D2, both of which used to 66 // have no base classes, but which now derive from __non_trivial_if. The layout of a class 67 // that inherits from both D1 and D2 will change because the two __non_trivial_if base 68 // classes are not allowed to share the same address. 69 // 70 // By making those __non_trivial_if base classes unique, we work around this problem and 71 // it is safe to start deriving from __non_trivial_if in existing classes. 72 template <bool _Cond, class _Unique> 73 struct __non_trivial_if { }; 74 75 template <class _Unique> 76 struct __non_trivial_if<true, _Unique> { 77 _LIBCPP_INLINE_VISIBILITY 78 _LIBCPP_CONSTEXPR __non_trivial_if() _NOEXCEPT { } 79 }; 80 81 // allocator 82 // 83 // Note: For ABI compatibility between C++20 and previous standards, we make 84 // allocator<void> trivial in C++20. 85 86 template <class _Tp> 87 class _LIBCPP_TEMPLATE_VIS allocator 88 : private __non_trivial_if<!is_void<_Tp>::value, allocator<_Tp> > 89 { 90 static_assert(!is_volatile<_Tp>::value, "std::allocator does not support volatile types"); 91 public: 92 typedef size_t size_type; 93 typedef ptrdiff_t difference_type; 94 typedef _Tp value_type; 95 typedef true_type propagate_on_container_move_assignment; 96 typedef true_type is_always_equal; 97 98 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 99 allocator() _NOEXCEPT = default; 100 101 template <class _Up> 102 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 103 allocator(const allocator<_Up>&) _NOEXCEPT { } 104 105 _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 106 _Tp* allocate(size_t __n) { 107 if (__n > allocator_traits<allocator>::max_size(*this)) 108 __throw_bad_array_new_length(); 109 if (__libcpp_is_constant_evaluated()) { 110 return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp))); 111 } else { 112 return static_cast<_Tp*>(_VSTD::__libcpp_allocate(__n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp))); 113 } 114 } 115 116 #if _LIBCPP_STD_VER > 20 117 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr 118 allocation_result<_Tp*> allocate_at_least(size_t __n) { 119 return {allocate(__n), __n}; 120 } 121 #endif 122 123 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 124 void deallocate(_Tp* __p, size_t __n) _NOEXCEPT { 125 if (__libcpp_is_constant_evaluated()) { 126 ::operator delete(__p); 127 } else { 128 _VSTD::__libcpp_deallocate((void*)__p, __n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp)); 129 } 130 } 131 132 // C++20 Removed members 133 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS) 134 _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp* pointer; 135 _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp* const_pointer; 136 _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp& reference; 137 _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp& const_reference; 138 139 template <class _Up> 140 struct _LIBCPP_DEPRECATED_IN_CXX17 rebind { 141 typedef allocator<_Up> other; 142 }; 143 144 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY 145 pointer address(reference __x) const _NOEXCEPT { 146 return _VSTD::addressof(__x); 147 } 148 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY 149 const_pointer address(const_reference __x) const _NOEXCEPT { 150 return _VSTD::addressof(__x); 151 } 152 153 _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_DEPRECATED_IN_CXX17 154 _Tp* allocate(size_t __n, const void*) { 155 return allocate(__n); 156 } 157 158 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY size_type max_size() const _NOEXCEPT { 159 return size_type(~0) / sizeof(_Tp); 160 } 161 162 template <class _Up, class... _Args> 163 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY 164 void construct(_Up* __p, _Args&&... __args) { 165 ::new ((void*)__p) _Up(_VSTD::forward<_Args>(__args)...); 166 } 167 168 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY 169 void destroy(pointer __p) { 170 __p->~_Tp(); 171 } 172 #endif 173 }; 174 175 template <class _Tp> 176 class _LIBCPP_TEMPLATE_VIS allocator<const _Tp> 177 : private __non_trivial_if<!is_void<_Tp>::value, allocator<const _Tp> > 178 { 179 static_assert(!is_volatile<_Tp>::value, "std::allocator does not support volatile types"); 180 public: 181 typedef size_t size_type; 182 typedef ptrdiff_t difference_type; 183 typedef const _Tp value_type; 184 typedef true_type propagate_on_container_move_assignment; 185 typedef true_type is_always_equal; 186 187 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 188 allocator() _NOEXCEPT = default; 189 190 template <class _Up> 191 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 192 allocator(const allocator<_Up>&) _NOEXCEPT { } 193 194 _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 195 const _Tp* allocate(size_t __n) { 196 if (__n > allocator_traits<allocator>::max_size(*this)) 197 __throw_bad_array_new_length(); 198 if (__libcpp_is_constant_evaluated()) { 199 return static_cast<const _Tp*>(::operator new(__n * sizeof(_Tp))); 200 } else { 201 return static_cast<const _Tp*>(_VSTD::__libcpp_allocate(__n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp))); 202 } 203 } 204 205 #if _LIBCPP_STD_VER > 20 206 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr 207 allocation_result<const _Tp*> allocate_at_least(size_t __n) { 208 return {allocate(__n), __n}; 209 } 210 #endif 211 212 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 213 void deallocate(const _Tp* __p, size_t __n) { 214 if (__libcpp_is_constant_evaluated()) { 215 ::operator delete(const_cast<_Tp*>(__p)); 216 } else { 217 _VSTD::__libcpp_deallocate((void*) const_cast<_Tp *>(__p), __n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp)); 218 } 219 } 220 221 // C++20 Removed members 222 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS) 223 _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp* pointer; 224 _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp* const_pointer; 225 _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp& reference; 226 _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp& const_reference; 227 228 template <class _Up> 229 struct _LIBCPP_DEPRECATED_IN_CXX17 rebind { 230 typedef allocator<_Up> other; 231 }; 232 233 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY 234 const_pointer address(const_reference __x) const _NOEXCEPT { 235 return _VSTD::addressof(__x); 236 } 237 238 _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_DEPRECATED_IN_CXX17 239 const _Tp* allocate(size_t __n, const void*) { 240 return allocate(__n); 241 } 242 243 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY size_type max_size() const _NOEXCEPT { 244 return size_type(~0) / sizeof(_Tp); 245 } 246 247 template <class _Up, class... _Args> 248 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY 249 void construct(_Up* __p, _Args&&... __args) { 250 ::new ((void*)__p) _Up(_VSTD::forward<_Args>(__args)...); 251 } 252 253 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY 254 void destroy(pointer __p) { 255 __p->~_Tp(); 256 } 257 #endif 258 }; 259 260 template <class _Tp, class _Up> 261 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 262 bool operator==(const allocator<_Tp>&, const allocator<_Up>&) _NOEXCEPT {return true;} 263 264 template <class _Tp, class _Up> 265 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 266 bool operator!=(const allocator<_Tp>&, const allocator<_Up>&) _NOEXCEPT {return false;} 267 268 _LIBCPP_END_NAMESPACE_STD 269 270 #endif // _LIBCPP___MEMORY_ALLOCATOR_H 271