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

   1 // -*- C++ -*- Exception handling and frame unwind runtime interface routines.
   2 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
   3 // 2011  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 // This is derived from the C++ ABI for IA-64.  Where we diverge
  27 // for cross-architecture compatibility are noted with "@@@".
  28
  29 #ifndef _UNWIND_CXX_H
  30 #define _UNWIND_CXX_H 1
  31
  32 // Level 2: C++ ABI
  33
  34 #include <typeinfo>
  35 #include <exception>
  36 #include <cstddef>
  37 #include "unwind.h"
  38 #include <bits/atomic_word.h>
  39 #include <cxxabi.h>
  40
  41 #pragma GCC visibility push(default)
  42
  43 namespace __cxxabiv1
  44 {
  45
  46 // A primary C++ exception object consists of a header, which is a wrapper
  47 // around an unwind object header with additional C++ specific information,
  48 // followed by the exception object itself.
  49
  50 struct __cxa_exception
  51 {
  52   // Manage the exception object itself.
  53   std::type_info *exceptionType;
  54   void (_GLIBCXX_CDTOR_CALLABI *exceptionDestructor)(void *);
  55
  56   // The C++ standard has entertaining rules wrt calling set_terminate
  57   // and set_unexpected in the middle of the exception cleanup process.
  58   std::unexpected_handler unexpectedHandler;
  59   std::terminate_handler terminateHandler;
  60
  61   // The caught exception stack threads through here.
  62   __cxa_exception *nextException;
  63
  64   // How many nested handlers have caught this exception.  A negated
  65   // value is a signal that this object has been rethrown.
  66   int handlerCount;
  67
  68 #ifdef __ARM_EABI_UNWINDER__
  69   // Stack of exceptions in cleanups.
  70   __cxa_exception* nextPropagatingException;
  71
  72   // The nuber of active cleanup handlers for this exception.
  73   int propagationCount;
  74 #else
  75   // Cache parsed handler data from the personality routine Phase 1
  76   // for Phase 2 and __cxa_call_unexpected.
  77   int handlerSwitchValue;
  78   const unsigned char *actionRecord;
  79   const unsigned char *languageSpecificData;
  80   _Unwind_Ptr catchTemp;
  81   void *adjustedPtr;
  82 #endif
  83
  84   // The generic exception header.  Must be last.
  85   _Unwind_Exception unwindHeader;
  86 };
  87
  88 struct __cxa_refcounted_exception
  89 {
  90   // Manage this header.
  91   _Atomic_word referenceCount;
  92   // __cxa_exception must be last, and no padding can be after it.
  93   __cxa_exception exc;
  94 };
  95
  96 // A dependent C++ exception object consists of a wrapper around an unwind
  97 // object header with additional C++ specific information, containing a pointer
  98 // to a primary exception object.
  99
 100 struct __cxa_dependent_exception
 101 {
 102   // The primary exception this thing depends on.
 103   void *primaryException;
 104
 105   // The C++ standard has entertaining rules wrt calling set_terminate
 106   // and set_unexpected in the middle of the exception cleanup process.
 107   std::unexpected_handler unexpectedHandler;
 108   std::terminate_handler terminateHandler;
 109
 110   // The caught exception stack threads through here.
 111   __cxa_exception *nextException;
 112
 113   // How many nested handlers have caught this exception.  A negated
 114   // value is a signal that this object has been rethrown.
 115   int handlerCount;
 116
 117 #ifdef __ARM_EABI_UNWINDER__
 118   // Stack of exceptions in cleanups.
 119   __cxa_exception* nextPropagatingException;
 120
 121   // The nuber of active cleanup handlers for this exception.
 122   int propagationCount;
 123 #else
 124   // Cache parsed handler data from the personality routine Phase 1
 125   // for Phase 2 and __cxa_call_unexpected.
 126   int handlerSwitchValue;
 127   const unsigned char *actionRecord;
 128   const unsigned char *languageSpecificData;
 129   _Unwind_Ptr catchTemp;
 130   void *adjustedPtr;
 131 #endif
 132
 133   // The generic exception header.  Must be last.
 134   _Unwind_Exception unwindHeader;
 135 };
 136
 137 // Each thread in a C++ program has access to a __cxa_eh_globals object.
 138 struct __cxa_eh_globals
 139 {
 140   __cxa_exception *caughtExceptions;
 141   unsigned int uncaughtExceptions;
 142 #ifdef __ARM_EABI_UNWINDER__
 143   __cxa_exception* propagatingExceptions;
 144 #endif
 145 };
 146
 147 // @@@ These are not directly specified by the IA-64 C++ ABI.
 148
 149 // Handles re-checking the exception specification if unexpectedHandler
 150 // throws, and if bad_exception needs to be thrown.  Called from the
 151 // compiler.
 152 extern "C" void __cxa_call_unexpected (void *) __attribute__((__noreturn__));
 153 extern "C" void __cxa_call_terminate (_Unwind_Exception*) throw ()
 154   __attribute__((__noreturn__));
 155
 156 #ifdef __ARM_EABI_UNWINDER__
 157 // Arm EABI specified routines.
 158 typedef enum {
 159   ctm_failed = 0,
 160   ctm_succeeded = 1,
 161   ctm_succeeded_with_ptr_to_base = 2
 162 } __cxa_type_match_result;
 163 extern "C" __cxa_type_match_result __cxa_type_match(_Unwind_Exception*,
 164                                                     const std::type_info*,
 165                                                     bool, void**);
 166 extern "C" bool __cxa_begin_cleanup (_Unwind_Exception*);
 167 extern "C" void __cxa_end_cleanup (void);
 168 #endif
 169
 170 // Handles cleanup from transactional memory restart.
 171 extern "C" void __cxa_tm_cleanup (void *, void *, unsigned int) throw();
 172
 173 // Invokes given handler, dying appropriately if the user handler was
 174 // so inconsiderate as to return.
 175 extern void __terminate(std::terminate_handler) throw ()
 176   __attribute__((__noreturn__));
 177 extern void __unexpected(std::unexpected_handler)
 178   __attribute__((__noreturn__));
 179
 180 // The current installed user handlers.
 181 extern std::terminate_handler __terminate_handler;
 182 extern std::unexpected_handler __unexpected_handler;
 183
 184 // These are explicitly GNU C++ specific.
 185
 186 // Acquire the C++ exception header from the C++ object.
 187 static inline __cxa_exception *
 188 __get_exception_header_from_obj (void *ptr)
 189 {
 190   return reinterpret_cast<__cxa_exception *>(ptr) - 1;
 191 }
 192
 193 // Acquire the C++ exception header from the generic exception header.
 194 static inline __cxa_exception *
 195 __get_exception_header_from_ue (_Unwind_Exception *exc)
 196 {
 197   return reinterpret_cast<__cxa_exception *>(exc + 1) - 1;
 198 }
 199
 200 // Acquire the C++ refcounted exception header from the C++ object.
 201 static inline __cxa_refcounted_exception *
 202 __get_refcounted_exception_header_from_obj (void *ptr)
 203 {
 204   return reinterpret_cast<__cxa_refcounted_exception *>(ptr) - 1;
 205 }
 206
 207 // Acquire the C++ refcounted exception header from the generic exception
 208 // header.
 209 static inline __cxa_refcounted_exception *
 210 __get_refcounted_exception_header_from_ue (_Unwind_Exception *exc)
 211 {
 212   return reinterpret_cast<__cxa_refcounted_exception *>(exc + 1) - 1;
 213 }
 214
 215 static inline __cxa_dependent_exception *
 216 __get_dependent_exception_from_ue (_Unwind_Exception *exc)
 217 {
 218   return reinterpret_cast<__cxa_dependent_exception *>(exc + 1) - 1;
 219 }
 220
 221 #ifdef __ARM_EABI_UNWINDER__
 222 static inline bool
 223 __is_gxx_exception_class(_Unwind_Exception_Class c)
 224 {
 225   // TODO: Take advantage of the fact that c will always be word aligned.
 226   return c[0] == 'G'
 227          && c[1] == 'N'
 228          && c[2] == 'U'
 229          && c[3] == 'C'
 230          && c[4] == 'C'
 231          && c[5] == '+'
 232          && c[6] == '+'
 233          && (c[7] == '\0' || c[7] == '\x01');
 234 }
 235
 236 // Only checks for primary or dependent, but not that it is a C++ exception at
 237 // all.
 238 static inline bool
 239 __is_dependent_exception(_Unwind_Exception_Class c)
 240 {
 241   return c[7] == '\x01';
 242 }
 243
 244 static inline void
 245 __GXX_INIT_PRIMARY_EXCEPTION_CLASS(_Unwind_Exception_Class c)
 246 {
 247   c[0] = 'G';
 248   c[1] = 'N';
 249   c[2] = 'U';
 250   c[3] = 'C';
 251   c[4] = 'C';
 252   c[5] = '+';
 253   c[6] = '+';
 254   c[7] = '\0';
 255 }
 256
 257 static inline void
 258 __GXX_INIT_DEPENDENT_EXCEPTION_CLASS(_Unwind_Exception_Class c)
 259 {
 260   c[0] = 'G';
 261   c[1] = 'N';
 262   c[2] = 'U';
 263   c[3] = 'C';
 264   c[4] = 'C';
 265   c[5] = '+';
 266   c[6] = '+';
 267   c[7] = '\x01';
 268 }
 269
 270 static inline bool
 271 __is_gxx_forced_unwind_class(_Unwind_Exception_Class c)
 272 {
 273   return c[0] == 'G'
 274          && c[1] == 'N'
 275          && c[2] == 'U'
 276          && c[3] == 'C'
 277          && c[4] == 'F'
 278          && c[5] == 'O'
 279          && c[6] == 'R'
 280          && c[7] == '\0';
 281 }
 282
 283 static inline void
 284 __GXX_INIT_FORCED_UNWIND_CLASS(_Unwind_Exception_Class c)
 285 {
 286   c[0] = 'G';
 287   c[1] = 'N';
 288   c[2] = 'U';
 289   c[3] = 'C';
 290   c[4] = 'F';
 291   c[5] = 'O';
 292   c[6] = 'R';
 293   c[7] = '\0';
 294 }
 295
 296 static inline void*
 297 __gxx_caught_object(_Unwind_Exception* eo)
 298 {
 299   return (void*)eo->barrier_cache.bitpattern[0];
 300 }
 301 #else // !__ARM_EABI_UNWINDER__
 302 // This is the primary exception class we report -- "GNUCC++\0".
 303 const _Unwind_Exception_Class __gxx_primary_exception_class
 304 = ((((((((_Unwind_Exception_Class) 'G'
 305          << 8 | (_Unwind_Exception_Class) 'N')
 306         << 8 | (_Unwind_Exception_Class) 'U')
 307        << 8 | (_Unwind_Exception_Class) 'C')
 308       << 8 | (_Unwind_Exception_Class) 'C')
 309      << 8 | (_Unwind_Exception_Class) '+')
 310     << 8 | (_Unwind_Exception_Class) '+')
 311    << 8 | (_Unwind_Exception_Class) '\0');
 312
 313 // This is the dependent (from std::rethrow_exception) exception class we report
 314 // "GNUCC++\x01"
 315 const _Unwind_Exception_Class __gxx_dependent_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) '\x01');
 324
 325 static inline bool
 326 __is_gxx_exception_class(_Unwind_Exception_Class c)
 327 {
 328   return c == __gxx_primary_exception_class
 329       || c == __gxx_dependent_exception_class;
 330 }
 331
 332 // Only checks for primary or dependent, but not that it is a C++ exception at
 333 // all.
 334 static inline bool
 335 __is_dependent_exception(_Unwind_Exception_Class c)
 336 {
 337   return (c & 1);
 338 }
 339
 340 #define __GXX_INIT_PRIMARY_EXCEPTION_CLASS(c) c = __gxx_primary_exception_class
 341 #define __GXX_INIT_DEPENDENT_EXCEPTION_CLASS(c) \
 342   c = __gxx_dependent_exception_class
 343
 344 // GNU C++ personality routine, Version 0.
 345 extern "C" _Unwind_Reason_Code __gxx_personality_v0
 346      (int, _Unwind_Action, _Unwind_Exception_Class,
 347       struct _Unwind_Exception *, struct _Unwind_Context *);
 348
 349 // GNU C++ sjlj personality routine, Version 0.
 350 extern "C" _Unwind_Reason_Code __gxx_personality_sj0
 351      (int, _Unwind_Action, _Unwind_Exception_Class,
 352       struct _Unwind_Exception *, struct _Unwind_Context *);
 353
 354 static inline void*
 355 __gxx_caught_object(_Unwind_Exception* eo)
 356 {
 357   // Bad as it looks, this actually works for dependent exceptions too.
 358   __cxa_exception* header = __get_exception_header_from_ue (eo);
 359   return header->adjustedPtr;
 360 }
 361 #endif // !__ARM_EABI_UNWINDER__
 362
 363 static inline void*
 364 __get_object_from_ue(_Unwind_Exception* eo) throw()
 365 {
 366   return __is_dependent_exception (eo->exception_class) ?
 367     __get_dependent_exception_from_ue (eo)->primaryException :
 368     eo + 1;
 369 }
 370
 371 static inline void *
 372 __get_object_from_ambiguous_exception(__cxa_exception *p_or_d) throw()
 373 {
 374         return __get_object_from_ue (&p_or_d->unwindHeader);
 375 }
 376
 377
 378 } /* namespace __cxxabiv1 */
 379
 380 #pragma GCC visibility pop
 381
 382 #endif // _UNWIND_CXX_H