1 // Exception Handling support header (exception_ptr class) for -*- C++ -*- 2 3 // Copyright (C) 2008-2022 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 bits/exception_ptr.h 27 * This is an internal header file, included by other library headers. 28 * Do not attempt to use it directly. @headername{exception} 29 */ 30 31 #ifndef _EXCEPTION_PTR_H 32 #define _EXCEPTION_PTR_H 33 34 #pragma GCC visibility push(default) 35 36 #include <bits/c++config.h> 37 #include <bits/exception_defines.h> 38 #include <bits/cxxabi_init_exception.h> 39 #include <typeinfo> 40 #include <new> 41 42 #if __cplusplus >= 201103L 43 # include <bits/move.h> 44 #endif 45 46 #ifdef _GLIBCXX_EH_PTR_RELOPS_COMPAT 47 # define _GLIBCXX_EH_PTR_USED __attribute__((__used__)) 48 #else 49 # define _GLIBCXX_EH_PTR_USED 50 #endif 51 52 extern "C++" { 53 54 namespace std 55 { 56 class type_info; 57 58 /** 59 * @addtogroup exceptions 60 * @{ 61 */ 62 63 namespace __exception_ptr 64 { 65 class exception_ptr; 66 } 67 68 using __exception_ptr::exception_ptr; 69 70 /** Obtain an exception_ptr to the currently handled exception. If there 71 * is none, or the currently handled exception is foreign, return the null 72 * value. 73 */ 74 exception_ptr current_exception() _GLIBCXX_USE_NOEXCEPT; 75 76 template<typename _Ex> 77 exception_ptr make_exception_ptr(_Ex) _GLIBCXX_USE_NOEXCEPT; 78 79 /// Throw the object pointed to by the exception_ptr. 80 void rethrow_exception(exception_ptr) __attribute__ ((__noreturn__)); 81 82 namespace __exception_ptr 83 { 84 using std::rethrow_exception; 85 86 /** 87 * @brief An opaque pointer to an arbitrary exception. 88 * @ingroup exceptions 89 */ 90 class exception_ptr 91 { 92 void* _M_exception_object; 93 94 explicit exception_ptr(void* __e) _GLIBCXX_USE_NOEXCEPT; 95 96 void _M_addref() _GLIBCXX_USE_NOEXCEPT; 97 void _M_release() _GLIBCXX_USE_NOEXCEPT; 98 99 void *_M_get() const _GLIBCXX_NOEXCEPT __attribute__ ((__pure__)); 100 101 friend exception_ptr std::current_exception() _GLIBCXX_USE_NOEXCEPT; 102 friend void std::rethrow_exception(exception_ptr); 103 template<typename _Ex> 104 friend exception_ptr std::make_exception_ptr(_Ex) _GLIBCXX_USE_NOEXCEPT; 105 106 public: 107 exception_ptr() _GLIBCXX_USE_NOEXCEPT; 108 109 exception_ptr(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT; 110 111 #if __cplusplus >= 201103L exception_ptr(nullptr_t)112 exception_ptr(nullptr_t) noexcept 113 : _M_exception_object(nullptr) 114 { } 115 exception_ptr(exception_ptr && __o)116 exception_ptr(exception_ptr&& __o) noexcept 117 : _M_exception_object(__o._M_exception_object) 118 { __o._M_exception_object = nullptr; } 119 #endif 120 121 #if (__cplusplus < 201103L) || defined (_GLIBCXX_EH_PTR_COMPAT) 122 typedef void (exception_ptr::*__safe_bool)(); 123 124 // For construction from nullptr or 0. 125 exception_ptr(__safe_bool) _GLIBCXX_USE_NOEXCEPT; 126 #endif 127 128 exception_ptr& 129 operator=(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT; 130 131 #if __cplusplus >= 201103L 132 exception_ptr& 133 operator=(exception_ptr&& __o) noexcept 134 { 135 exception_ptr(static_cast<exception_ptr&&>(__o)).swap(*this); 136 return *this; 137 } 138 #endif 139 140 ~exception_ptr() _GLIBCXX_USE_NOEXCEPT; 141 142 void 143 swap(exception_ptr&) _GLIBCXX_USE_NOEXCEPT; 144 145 #ifdef _GLIBCXX_EH_PTR_COMPAT 146 // Retained for compatibility with CXXABI_1.3. 147 void _M_safe_bool_dummy() _GLIBCXX_USE_NOEXCEPT 148 __attribute__ ((__const__)); 149 bool operator!() const _GLIBCXX_USE_NOEXCEPT 150 __attribute__ ((__pure__)); 151 operator __safe_bool() const _GLIBCXX_USE_NOEXCEPT; 152 #endif 153 154 #if __cplusplus >= 201103L 155 explicit operator bool() const noexcept 156 { return _M_exception_object; } 157 #endif 158 159 #if __cpp_impl_three_way_comparison >= 201907L \ 160 && ! defined _GLIBCXX_EH_PTR_RELOPS_COMPAT 161 friend bool 162 operator==(const exception_ptr&, const exception_ptr&) noexcept = default; 163 #else 164 friend _GLIBCXX_EH_PTR_USED bool 165 operator==(const exception_ptr& __x, const exception_ptr& __y) 166 _GLIBCXX_USE_NOEXCEPT 167 { return __x._M_exception_object == __y._M_exception_object; } 168 169 friend _GLIBCXX_EH_PTR_USED bool 170 operator!=(const exception_ptr& __x, const exception_ptr& __y) 171 _GLIBCXX_USE_NOEXCEPT 172 { return __x._M_exception_object != __y._M_exception_object; } 173 #endif 174 175 const class std::type_info* 176 __cxa_exception_type() const _GLIBCXX_USE_NOEXCEPT 177 __attribute__ ((__pure__)); 178 }; 179 180 _GLIBCXX_EH_PTR_USED 181 inline exception_ptr()182 exception_ptr::exception_ptr() _GLIBCXX_USE_NOEXCEPT 183 : _M_exception_object(0) 184 { } 185 186 _GLIBCXX_EH_PTR_USED 187 inline exception_ptr(const exception_ptr & __other)188 exception_ptr::exception_ptr(const exception_ptr& __other) 189 _GLIBCXX_USE_NOEXCEPT 190 : _M_exception_object(__other._M_exception_object) 191 { 192 if (_M_exception_object) 193 _M_addref(); 194 } 195 196 _GLIBCXX_EH_PTR_USED 197 inline ~exception_ptr()198 exception_ptr::~exception_ptr() _GLIBCXX_USE_NOEXCEPT 199 { 200 if (_M_exception_object) 201 _M_release(); 202 } 203 204 _GLIBCXX_EH_PTR_USED 205 inline exception_ptr& 206 exception_ptr::operator=(const exception_ptr& __other) _GLIBCXX_USE_NOEXCEPT 207 { 208 exception_ptr(__other).swap(*this); 209 return *this; 210 } 211 212 _GLIBCXX_EH_PTR_USED 213 inline void swap(exception_ptr & __other)214 exception_ptr::swap(exception_ptr &__other) _GLIBCXX_USE_NOEXCEPT 215 { 216 void *__tmp = _M_exception_object; 217 _M_exception_object = __other._M_exception_object; 218 __other._M_exception_object = __tmp; 219 } 220 221 /// @relates exception_ptr 222 inline void swap(exception_ptr & __lhs,exception_ptr & __rhs)223 swap(exception_ptr& __lhs, exception_ptr& __rhs) 224 { __lhs.swap(__rhs); } 225 226 /// @cond undocumented 227 template<typename _Ex> 228 _GLIBCXX_CDTOR_CALLABI 229 inline void __dest_thunk(void * __x)230 __dest_thunk(void* __x) 231 { static_cast<_Ex*>(__x)->~_Ex(); } 232 /// @endcond 233 234 } // namespace __exception_ptr 235 236 /// Obtain an exception_ptr pointing to a copy of the supplied object. 237 #if (__cplusplus >= 201103L && __cpp_rtti) || __cpp_exceptions 238 template<typename _Ex> 239 exception_ptr make_exception_ptr(_Ex __ex)240 make_exception_ptr(_Ex __ex) _GLIBCXX_USE_NOEXCEPT 241 { 242 #if __cplusplus >= 201103L && __cpp_rtti 243 using _Ex2 = typename decay<_Ex>::type; 244 void* __e = __cxxabiv1::__cxa_allocate_exception(sizeof(_Ex)); 245 (void) __cxxabiv1::__cxa_init_primary_exception( 246 __e, const_cast<std::type_info*>(&typeid(_Ex)), 247 __exception_ptr::__dest_thunk<_Ex2>); 248 __try 249 { 250 ::new (__e) _Ex2(__ex); 251 return exception_ptr(__e); 252 } 253 __catch(...) 254 { 255 __cxxabiv1::__cxa_free_exception(__e); 256 return current_exception(); 257 } 258 #else 259 try 260 { 261 throw __ex; 262 } 263 catch(...) 264 { 265 return current_exception(); 266 } 267 #endif 268 } 269 #else // no RTTI and no exceptions 270 // This is always_inline so the linker will never use this useless definition 271 // instead of a working one compiled with RTTI and/or exceptions enabled. 272 template<typename _Ex> 273 __attribute__ ((__always_inline__)) 274 inline exception_ptr make_exception_ptr(_Ex)275 make_exception_ptr(_Ex) _GLIBCXX_USE_NOEXCEPT 276 { return exception_ptr(); } 277 #endif 278 279 #undef _GLIBCXX_EH_PTR_USED 280 281 /// @} group exceptions 282 } // namespace std 283 284 } // extern "C++" 285 286 #pragma GCC visibility pop 287 288 #endif 289