1 // -*- C++ -*- Exception handling and frame unwind runtime interface routines. 2 // Copyright (C) 2001-2013 Free Software Foundation, Inc. 3 // 4 // This file is part of GCC. 5 // 6 // GCC is free software; you can redistribute it and/or modify 7 // it under the terms of the GNU General Public License as published by 8 // the Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 // 11 // GCC is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU General Public License for more details. 15 // 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 // This is derived from the C++ ABI for IA-64. Where we diverge 26 // for cross-architecture compatibility are noted with "@@@". 27 28 #ifndef _UNWIND_CXX_H 29 #define _UNWIND_CXX_H 1 30 31 // Level 2: C++ ABI 32 33 #include <typeinfo> 34 #include <exception> 35 #include <cstddef> 36 #include "unwind.h" 37 #include <bits/atomic_word.h> 38 #include <cxxabi.h> 39 40 #ifdef _GLIBCXX_HAVE_SYS_SDT_H 41 #include <sys/sdt.h> 42 /* We only want to use stap probes starting with v3. Earlier versions 43 added too much startup cost. */ 44 #if defined (STAP_PROBE2) && _SDT_NOTE_TYPE >= 3 45 #define PROBE2(name, arg1, arg2) STAP_PROBE2 (libstdcxx, name, arg1, arg2) 46 #endif 47 #endif 48 49 #ifndef PROBE2 50 #define PROBE2(name, arg1, arg2) 51 #endif 52 53 #pragma GCC visibility push(default) 54 55 namespace __cxxabiv1 56 { 57 58 // A primary C++ exception object consists of a header, which is a wrapper 59 // around an unwind object header with additional C++ specific information, 60 // followed by the exception object itself. 61 62 struct __cxa_exception 63 { 64 // Manage the exception object itself. 65 std::type_info *exceptionType; 66 void (_GLIBCXX_CDTOR_CALLABI *exceptionDestructor)(void *); 67 68 // The C++ standard has entertaining rules wrt calling set_terminate 69 // and set_unexpected in the middle of the exception cleanup process. 70 std::unexpected_handler unexpectedHandler; 71 std::terminate_handler terminateHandler; 72 73 // The caught exception stack threads through here. 74 __cxa_exception *nextException; 75 76 // How many nested handlers have caught this exception. A negated 77 // value is a signal that this object has been rethrown. 78 int handlerCount; 79 80 #ifdef __ARM_EABI_UNWINDER__ 81 // Stack of exceptions in cleanups. 82 __cxa_exception* nextPropagatingException; 83 84 // The nuber of active cleanup handlers for this exception. 85 int propagationCount; 86 #else 87 // Cache parsed handler data from the personality routine Phase 1 88 // for Phase 2 and __cxa_call_unexpected. 89 int handlerSwitchValue; 90 const unsigned char *actionRecord; 91 const unsigned char *languageSpecificData; 92 _Unwind_Ptr catchTemp; 93 void *adjustedPtr; 94 #endif 95 96 // The generic exception header. Must be last. 97 _Unwind_Exception unwindHeader; 98 }; 99 100 struct __cxa_refcounted_exception 101 { 102 // Manage this header. 103 _Atomic_word referenceCount; 104 // __cxa_exception must be last, and no padding can be after it. 105 __cxa_exception exc; 106 }; 107 108 // A dependent C++ exception object consists of a wrapper around an unwind 109 // object header with additional C++ specific information, containing a pointer 110 // to a primary exception object. 111 112 struct __cxa_dependent_exception 113 { 114 // The primary exception this thing depends on. 115 void *primaryException; 116 117 // The C++ standard has entertaining rules wrt calling set_terminate 118 // and set_unexpected in the middle of the exception cleanup process. 119 std::unexpected_handler unexpectedHandler; 120 std::terminate_handler terminateHandler; 121 122 // The caught exception stack threads through here. 123 __cxa_exception *nextException; 124 125 // How many nested handlers have caught this exception. A negated 126 // value is a signal that this object has been rethrown. 127 int handlerCount; 128 129 #ifdef __ARM_EABI_UNWINDER__ 130 // Stack of exceptions in cleanups. 131 __cxa_exception* nextPropagatingException; 132 133 // The nuber of active cleanup handlers for this exception. 134 int propagationCount; 135 #else 136 // Cache parsed handler data from the personality routine Phase 1 137 // for Phase 2 and __cxa_call_unexpected. 138 int handlerSwitchValue; 139 const unsigned char *actionRecord; 140 const unsigned char *languageSpecificData; 141 _Unwind_Ptr catchTemp; 142 void *adjustedPtr; 143 #endif 144 145 // The generic exception header. Must be last. 146 _Unwind_Exception unwindHeader; 147 }; 148 149 // Each thread in a C++ program has access to a __cxa_eh_globals object. 150 struct __cxa_eh_globals 151 { 152 __cxa_exception *caughtExceptions; 153 unsigned int uncaughtExceptions; 154 #ifdef __ARM_EABI_UNWINDER__ 155 __cxa_exception* propagatingExceptions; 156 #endif 157 }; 158 159 // @@@ These are not directly specified by the IA-64 C++ ABI. 160 161 // Handles re-checking the exception specification if unexpectedHandler 162 // throws, and if bad_exception needs to be thrown. Called from the 163 // compiler. 164 extern "C" void __cxa_call_unexpected (void *) __attribute__((__noreturn__)); 165 extern "C" void __cxa_call_terminate (_Unwind_Exception*) throw () 166 __attribute__((__noreturn__)); 167 168 #ifdef __ARM_EABI_UNWINDER__ 169 // Arm EABI specified routines. 170 typedef enum { 171 ctm_failed = 0, 172 ctm_succeeded = 1, 173 ctm_succeeded_with_ptr_to_base = 2 174 } __cxa_type_match_result; 175 extern "C" __cxa_type_match_result __cxa_type_match(_Unwind_Exception*, 176 const std::type_info*, 177 bool, void**); 178 extern "C" bool __cxa_begin_cleanup (_Unwind_Exception*); 179 extern "C" void __cxa_end_cleanup (void); 180 #endif 181 182 // Handles cleanup from transactional memory restart. 183 extern "C" void __cxa_tm_cleanup (void *, void *, unsigned int) throw(); 184 185 // Invokes given handler, dying appropriately if the user handler was 186 // so inconsiderate as to return. 187 extern void __terminate(std::terminate_handler) throw () 188 __attribute__((__noreturn__)); 189 extern void __unexpected(std::unexpected_handler) 190 __attribute__((__noreturn__)); 191 192 // The current installed user handlers. 193 extern std::terminate_handler __terminate_handler; 194 extern std::unexpected_handler __unexpected_handler; 195 196 // These are explicitly GNU C++ specific. 197 198 // Acquire the C++ exception header from the C++ object. 199 static inline __cxa_exception * 200 __get_exception_header_from_obj (void *ptr) 201 { 202 return reinterpret_cast<__cxa_exception *>(ptr) - 1; 203 } 204 205 // Acquire the C++ exception header from the generic exception header. 206 static inline __cxa_exception * 207 __get_exception_header_from_ue (_Unwind_Exception *exc) 208 { 209 return reinterpret_cast<__cxa_exception *>(exc + 1) - 1; 210 } 211 212 // Acquire the C++ refcounted exception header from the C++ object. 213 static inline __cxa_refcounted_exception * 214 __get_refcounted_exception_header_from_obj (void *ptr) 215 { 216 return reinterpret_cast<__cxa_refcounted_exception *>(ptr) - 1; 217 } 218 219 // Acquire the C++ refcounted exception header from the generic exception 220 // header. 221 static inline __cxa_refcounted_exception * 222 __get_refcounted_exception_header_from_ue (_Unwind_Exception *exc) 223 { 224 return reinterpret_cast<__cxa_refcounted_exception *>(exc + 1) - 1; 225 } 226 227 static inline __cxa_dependent_exception * 228 __get_dependent_exception_from_ue (_Unwind_Exception *exc) 229 { 230 return reinterpret_cast<__cxa_dependent_exception *>(exc + 1) - 1; 231 } 232 233 #ifdef __ARM_EABI_UNWINDER__ 234 static inline bool 235 __is_gxx_exception_class(_Unwind_Exception_Class c) 236 { 237 // TODO: Take advantage of the fact that c will always be word aligned. 238 return c[0] == 'G' 239 && c[1] == 'N' 240 && c[2] == 'U' 241 && c[3] == 'C' 242 && c[4] == 'C' 243 && c[5] == '+' 244 && c[6] == '+' 245 && (c[7] == '\0' || c[7] == '\x01'); 246 } 247 248 // Only checks for primary or dependent, but not that it is a C++ exception at 249 // all. 250 static inline bool 251 __is_dependent_exception(_Unwind_Exception_Class c) 252 { 253 return c[7] == '\x01'; 254 } 255 256 static inline void 257 __GXX_INIT_PRIMARY_EXCEPTION_CLASS(_Unwind_Exception_Class c) 258 { 259 c[0] = 'G'; 260 c[1] = 'N'; 261 c[2] = 'U'; 262 c[3] = 'C'; 263 c[4] = 'C'; 264 c[5] = '+'; 265 c[6] = '+'; 266 c[7] = '\0'; 267 } 268 269 static inline void 270 __GXX_INIT_DEPENDENT_EXCEPTION_CLASS(_Unwind_Exception_Class c) 271 { 272 c[0] = 'G'; 273 c[1] = 'N'; 274 c[2] = 'U'; 275 c[3] = 'C'; 276 c[4] = 'C'; 277 c[5] = '+'; 278 c[6] = '+'; 279 c[7] = '\x01'; 280 } 281 282 static inline bool 283 __is_gxx_forced_unwind_class(_Unwind_Exception_Class c) 284 { 285 return c[0] == 'G' 286 && c[1] == 'N' 287 && c[2] == 'U' 288 && c[3] == 'C' 289 && c[4] == 'F' 290 && c[5] == 'O' 291 && c[6] == 'R' 292 && c[7] == '\0'; 293 } 294 295 static inline void 296 __GXX_INIT_FORCED_UNWIND_CLASS(_Unwind_Exception_Class c) 297 { 298 c[0] = 'G'; 299 c[1] = 'N'; 300 c[2] = 'U'; 301 c[3] = 'C'; 302 c[4] = 'F'; 303 c[5] = 'O'; 304 c[6] = 'R'; 305 c[7] = '\0'; 306 } 307 308 static inline void* 309 __gxx_caught_object(_Unwind_Exception* eo) 310 { 311 return (void*)eo->barrier_cache.bitpattern[0]; 312 } 313 #else // !__ARM_EABI_UNWINDER__ 314 // This is the primary exception class we report -- "GNUCC++\0". 315 const _Unwind_Exception_Class __gxx_primary_exception_class 316 = ((((((((_Unwind_Exception_Class) 'G' 317 << 8 | (_Unwind_Exception_Class) 'N') 318 << 8 | (_Unwind_Exception_Class) 'U') 319 << 8 | (_Unwind_Exception_Class) 'C') 320 << 8 | (_Unwind_Exception_Class) 'C') 321 << 8 | (_Unwind_Exception_Class) '+') 322 << 8 | (_Unwind_Exception_Class) '+') 323 << 8 | (_Unwind_Exception_Class) '\0'); 324 325 // This is the dependent (from std::rethrow_exception) exception class we report 326 // "GNUCC++\x01" 327 const _Unwind_Exception_Class __gxx_dependent_exception_class 328 = ((((((((_Unwind_Exception_Class) 'G' 329 << 8 | (_Unwind_Exception_Class) 'N') 330 << 8 | (_Unwind_Exception_Class) 'U') 331 << 8 | (_Unwind_Exception_Class) 'C') 332 << 8 | (_Unwind_Exception_Class) 'C') 333 << 8 | (_Unwind_Exception_Class) '+') 334 << 8 | (_Unwind_Exception_Class) '+') 335 << 8 | (_Unwind_Exception_Class) '\x01'); 336 337 static inline bool 338 __is_gxx_exception_class(_Unwind_Exception_Class c) 339 { 340 return c == __gxx_primary_exception_class 341 || c == __gxx_dependent_exception_class; 342 } 343 344 // Only checks for primary or dependent, but not that it is a C++ exception at 345 // all. 346 static inline bool 347 __is_dependent_exception(_Unwind_Exception_Class c) 348 { 349 return (c & 1); 350 } 351 352 #define __GXX_INIT_PRIMARY_EXCEPTION_CLASS(c) c = __gxx_primary_exception_class 353 #define __GXX_INIT_DEPENDENT_EXCEPTION_CLASS(c) \ 354 c = __gxx_dependent_exception_class 355 356 // GNU C++ personality routine, Version 0. 357 extern "C" _Unwind_Reason_Code __gxx_personality_v0 358 (int, _Unwind_Action, _Unwind_Exception_Class, 359 struct _Unwind_Exception *, struct _Unwind_Context *); 360 361 // GNU C++ sjlj personality routine, Version 0. 362 extern "C" _Unwind_Reason_Code __gxx_personality_sj0 363 (int, _Unwind_Action, _Unwind_Exception_Class, 364 struct _Unwind_Exception *, struct _Unwind_Context *); 365 366 static inline void* 367 __gxx_caught_object(_Unwind_Exception* eo) 368 { 369 // Bad as it looks, this actually works for dependent exceptions too. 370 __cxa_exception* header = __get_exception_header_from_ue (eo); 371 return header->adjustedPtr; 372 } 373 #endif // !__ARM_EABI_UNWINDER__ 374 375 static inline void* 376 __get_object_from_ue(_Unwind_Exception* eo) throw() 377 { 378 return __is_dependent_exception (eo->exception_class) ? 379 __get_dependent_exception_from_ue (eo)->primaryException : 380 eo + 1; 381 } 382 383 static inline void * 384 __get_object_from_ambiguous_exception(__cxa_exception *p_or_d) throw() 385 { 386 return __get_object_from_ue (&p_or_d->unwindHeader); 387 } 388 389 390 } /* namespace __cxxabiv1 */ 391 392 #pragma GCC visibility pop 393 394 #endif // _UNWIND_CXX_H 395