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/allocator_traits.h> 15 #include <__utility/forward.h> 16 #include <cstddef> 17 #include <new> 18 #include <stdexcept> 19 #include <type_traits> 20 21 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 22 #pragma GCC system_header 23 #endif 24 25 _LIBCPP_PUSH_MACROS 26 #include <__undef_macros> 27 28 _LIBCPP_BEGIN_NAMESPACE_STD 29 30 template <class _Tp> class allocator; 31 32 #if _LIBCPP_STD_VER <= 17 33 template <> 34 class _LIBCPP_TEMPLATE_VIS allocator<void> 35 { 36 public: 37 _LIBCPP_DEPRECATED_IN_CXX17 typedef void* pointer; 38 _LIBCPP_DEPRECATED_IN_CXX17 typedef const void* const_pointer; 39 _LIBCPP_DEPRECATED_IN_CXX17 typedef void value_type; 40 41 template <class _Up> struct _LIBCPP_DEPRECATED_IN_CXX17 rebind {typedef allocator<_Up> other;}; 42 }; 43 44 template <> 45 class _LIBCPP_TEMPLATE_VIS allocator<const void> 46 { 47 public: 48 _LIBCPP_DEPRECATED_IN_CXX17 typedef const void* pointer; 49 _LIBCPP_DEPRECATED_IN_CXX17 typedef const void* const_pointer; 50 _LIBCPP_DEPRECATED_IN_CXX17 typedef const void value_type; 51 52 template <class _Up> struct _LIBCPP_DEPRECATED_IN_CXX17 rebind {typedef allocator<_Up> other;}; 53 }; 54 #endif 55 56 // This class provides a non-trivial default constructor to the class that derives from it 57 // if the condition is satisfied. 58 // 59 // The second template parameter exists to allow giving a unique type to __non_trivial_if, 60 // which makes it possible to avoid breaking the ABI when making this a base class of an 61 // existing class. Without that, imagine we have classes D1 and D2, both of which used to 62 // have no base classes, but which now derive from __non_trivial_if. The layout of a class 63 // that inherits from both D1 and D2 will change because the two __non_trivial_if base 64 // classes are not allowed to share the same address. 65 // 66 // By making those __non_trivial_if base classes unique, we work around this problem and 67 // it is safe to start deriving from __non_trivial_if in existing classes. 68 template <bool _Cond, class _Unique> 69 struct __non_trivial_if { }; 70 71 template <class _Unique> 72 struct __non_trivial_if<true, _Unique> { 73 _LIBCPP_INLINE_VISIBILITY 74 _LIBCPP_CONSTEXPR __non_trivial_if() _NOEXCEPT { } 75 }; 76 77 // allocator 78 // 79 // Note: For ABI compatibility between C++20 and previous standards, we make 80 // allocator<void> trivial in C++20. 81 82 template <class _Tp> 83 class _LIBCPP_TEMPLATE_VIS allocator 84 : private __non_trivial_if<!is_void<_Tp>::value, allocator<_Tp> > 85 { 86 public: 87 typedef size_t size_type; 88 typedef ptrdiff_t difference_type; 89 typedef _Tp value_type; 90 typedef true_type propagate_on_container_move_assignment; 91 typedef true_type is_always_equal; 92 93 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 94 allocator() _NOEXCEPT _LIBCPP_DEFAULT 95 96 template <class _Up> 97 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 98 allocator(const allocator<_Up>&) _NOEXCEPT { } 99 100 _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 101 _Tp* allocate(size_t __n) { 102 if (__n > allocator_traits<allocator>::max_size(*this)) 103 __throw_length_error("allocator<T>::allocate(size_t n)" 104 " 'n' exceeds maximum supported size"); 105 if (__libcpp_is_constant_evaluated()) { 106 return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp))); 107 } else { 108 return static_cast<_Tp*>(_VSTD::__libcpp_allocate(__n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp))); 109 } 110 } 111 112 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 113 void deallocate(_Tp* __p, size_t __n) _NOEXCEPT { 114 if (__libcpp_is_constant_evaluated()) { 115 ::operator delete(__p); 116 } else { 117 _VSTD::__libcpp_deallocate((void*)__p, __n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp)); 118 } 119 } 120 121 // C++20 Removed members 122 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS) 123 _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp* pointer; 124 _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp* const_pointer; 125 _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp& reference; 126 _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp& const_reference; 127 128 template <class _Up> 129 struct _LIBCPP_DEPRECATED_IN_CXX17 rebind { 130 typedef allocator<_Up> other; 131 }; 132 133 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY 134 pointer address(reference __x) const _NOEXCEPT { 135 return _VSTD::addressof(__x); 136 } 137 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY 138 const_pointer address(const_reference __x) const _NOEXCEPT { 139 return _VSTD::addressof(__x); 140 } 141 142 _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_DEPRECATED_IN_CXX17 143 _Tp* allocate(size_t __n, const void*) { 144 return allocate(__n); 145 } 146 147 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY size_type max_size() const _NOEXCEPT { 148 return size_type(~0) / sizeof(_Tp); 149 } 150 151 template <class _Up, class... _Args> 152 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY 153 void construct(_Up* __p, _Args&&... __args) { 154 ::new ((void*)__p) _Up(_VSTD::forward<_Args>(__args)...); 155 } 156 157 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY 158 void destroy(pointer __p) { 159 __p->~_Tp(); 160 } 161 #endif 162 }; 163 164 template <class _Tp> 165 class _LIBCPP_TEMPLATE_VIS allocator<const _Tp> 166 : private __non_trivial_if<!is_void<_Tp>::value, allocator<const _Tp> > 167 { 168 public: 169 typedef size_t size_type; 170 typedef ptrdiff_t difference_type; 171 typedef const _Tp value_type; 172 typedef true_type propagate_on_container_move_assignment; 173 typedef true_type is_always_equal; 174 175 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 176 allocator() _NOEXCEPT _LIBCPP_DEFAULT 177 178 template <class _Up> 179 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 180 allocator(const allocator<_Up>&) _NOEXCEPT { } 181 182 _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 183 const _Tp* allocate(size_t __n) { 184 if (__n > allocator_traits<allocator>::max_size(*this)) 185 __throw_length_error("allocator<const T>::allocate(size_t n)" 186 " 'n' exceeds maximum supported size"); 187 if (__libcpp_is_constant_evaluated()) { 188 return static_cast<const _Tp*>(::operator new(__n * sizeof(_Tp))); 189 } else { 190 return static_cast<const _Tp*>(_VSTD::__libcpp_allocate(__n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp))); 191 } 192 } 193 194 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 195 void deallocate(const _Tp* __p, size_t __n) { 196 if (__libcpp_is_constant_evaluated()) { 197 ::operator delete(const_cast<_Tp*>(__p)); 198 } else { 199 _VSTD::__libcpp_deallocate((void*) const_cast<_Tp *>(__p), __n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp)); 200 } 201 } 202 203 // C++20 Removed members 204 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS) 205 _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp* pointer; 206 _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp* const_pointer; 207 _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp& reference; 208 _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp& const_reference; 209 210 template <class _Up> 211 struct _LIBCPP_DEPRECATED_IN_CXX17 rebind { 212 typedef allocator<_Up> other; 213 }; 214 215 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY 216 const_pointer address(const_reference __x) const _NOEXCEPT { 217 return _VSTD::addressof(__x); 218 } 219 220 _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_DEPRECATED_IN_CXX17 221 const _Tp* allocate(size_t __n, const void*) { 222 return allocate(__n); 223 } 224 225 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY size_type max_size() const _NOEXCEPT { 226 return size_type(~0) / sizeof(_Tp); 227 } 228 229 template <class _Up, class... _Args> 230 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY 231 void construct(_Up* __p, _Args&&... __args) { 232 ::new ((void*)__p) _Up(_VSTD::forward<_Args>(__args)...); 233 } 234 235 _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY 236 void destroy(pointer __p) { 237 __p->~_Tp(); 238 } 239 #endif 240 }; 241 242 template <class _Tp, class _Up> 243 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 244 bool operator==(const allocator<_Tp>&, const allocator<_Up>&) _NOEXCEPT {return true;} 245 246 template <class _Tp, class _Up> 247 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 248 bool operator!=(const allocator<_Tp>&, const allocator<_Up>&) _NOEXCEPT {return false;} 249 250 _LIBCPP_END_NAMESPACE_STD 251 252 _LIBCPP_POP_MACROS 253 254 #endif // _LIBCPP___MEMORY_ALLOCATOR_H 255