libstdc++-v3/libsupc++/unwind-cxx.h

   1 // -*- C++ -*- Exception handling and frame unwind runtime interface routines.
   2 // Copyright (C) 2001-2014 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