contrib/gcc-4.4/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
   3 // 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
  40 #pragma GCC visibility push(default)
  41
  42 namespace __cxxabiv1
  43 {
  44
  45 // A primary C++ exception object consists of a header, which is a wrapper
  46 // around an unwind object header with additional C++ specific information,
  47 // followed by the exception object itself.
  48
  49 struct __cxa_exception
  50 {
  51   // Manage the exception object itself.
  52   std::type_info *exceptionType;
  53   void (*exceptionDestructor)(void *);
  54
  55   // The C++ standard has entertaining rules wrt calling set_terminate
  56   // and set_unexpected in the middle of the exception cleanup process.
  57   std::unexpected_handler unexpectedHandler;
  58   std::terminate_handler terminateHandler;
  59
  60   // The caught exception stack threads through here.
  61   __cxa_exception *nextException;
  62
  63   // How many nested handlers have caught this exception.  A negated
  64   // value is a signal that this object has been rethrown.
  65   int handlerCount;
  66
  67 #ifdef __ARM_EABI_UNWINDER__
  68   // Stack of exceptions in cleanups.
  69   __cxa_exception* nextPropagatingException;
  70
  71   // The nuber of active cleanup handlers for this exception.
  72   int propagationCount;
  73 #else
  74   // Cache parsed handler data from the personality routine Phase 1
  75   // for Phase 2 and __cxa_call_unexpected.
  76   int handlerSwitchValue;
  77   const unsigned char *actionRecord;
  78   const unsigned char *languageSpecificData;
  79   _Unwind_Ptr catchTemp;
  80   void *adjustedPtr;
  81 #endif
  82
  83   // The generic exception header.  Must be last.
  84   _Unwind_Exception unwindHeader;
  85 };
  86
  87 struct __cxa_refcounted_exception
  88 {
  89   // Manage this header.
  90   _Atomic_word referenceCount;
  91   // __cxa_exception must be last, and no padding can be after it.
  92   __cxa_exception exc;
  93 };
  94
  95 // A dependent C++ exception object consists of a wrapper around an unwind
  96 // object header with additional C++ specific information, containing a pointer
  97 // to a primary exception object.
  98
  99 struct __cxa_dependent_exception
 100 {
 101   // The primary exception this thing depends on.
 102   void *primaryException;
 103
 104   // The C++ standard has entertaining rules wrt calling set_terminate
 105   // and set_unexpected in the middle of the exception cleanup process.
 106   std::unexpected_handler unexpectedHandler;
 107   std::terminate_handler terminateHandler;
 108
 109   // The caught exception stack threads through here.
 110   __cxa_exception *nextException;
 111
 112   // How many nested handlers have caught this exception.  A negated
 113   // value is a signal that this object has been rethrown.
 114   int handlerCount;
 115
 116 #ifdef __ARM_EABI_UNWINDER__
 117   // Stack of exceptions in cleanups.
 118   __cxa_exception* nextPropagatingException;
 119
 120   // The nuber of active cleanup handlers for this exception.
 121   int propagationCount;
 122 #else
 123   // Cache parsed handler data from the personality routine Phase 1
 124   // for Phase 2 and __cxa_call_unexpected.
 125   int handlerSwitchValue;
 126   const unsigned char *actionRecord;
 127   const unsigned char *languageSpecificData;
 128   _Unwind_Ptr catchTemp;
 129   void *adjustedPtr;
 130 #endif
 131
 132   // The generic exception header.  Must be last.
 133   _Unwind_Exception unwindHeader;
 134 };
 135
 136 // Each thread in a C++ program has access to a __cxa_eh_globals object.
 137 struct __cxa_eh_globals
 138 {
 139   __cxa_exception *caughtExceptions;
 140   unsigned int uncaughtExceptions;
 141 #ifdef __ARM_EABI_UNWINDER__
 142   __cxa_exception* propagatingExceptions;
 143 #endif
 144 };
 145
 146
 147 // The __cxa_eh_globals for the current thread can be obtained by using
 148 // either of the following functions.  The "fast" version assumes at least
 149 // one prior call of __cxa_get_globals has been made from the current
 150 // thread, so no initialization is necessary.
 151 extern "C" __cxa_eh_globals *__cxa_get_globals () throw();
 152 extern "C" __cxa_eh_globals *__cxa_get_globals_fast () throw();
 153
 154 // Allocate memory for the primary exception plus the thrown object.
 155 extern "C" void *__cxa_allocate_exception(std::size_t thrown_size) throw();
 156
 157 // Free the space allocated for the primary exception.
 158 extern "C" void __cxa_free_exception(void *thrown_exception) throw();
 159
 160 // Allocate memory for a dependent exception.
 161 extern "C" __cxa_dependent_exception*
 162 __cxa_allocate_dependent_exception() throw();
 163
 164 // Free the space allocated for the dependent exception.
 165 extern "C" void
 166 __cxa_free_dependent_exception(__cxa_dependent_exception *ex) throw();
 167
 168 // Throw the exception.
 169 extern "C" void __cxa_throw (void *thrown_exception,
 170                              std::type_info *tinfo,
 171                              void (*dest) (void *))
 172      __attribute__((noreturn));
 173
 174 // Used to implement exception handlers.
 175 extern "C" void *__cxa_get_exception_ptr (void *) throw();
 176 extern "C" void *__cxa_begin_catch (void *) throw();
 177 extern "C" void __cxa_end_catch ();
 178 extern "C" void __cxa_rethrow () __attribute__((noreturn));
 179
 180 // These facilitate code generation for recurring situations.
 181 extern "C" void __cxa_bad_cast ();
 182 extern "C" void __cxa_bad_typeid ();
 183
 184 // @@@ These are not directly specified by the IA-64 C++ ABI.
 185
 186 // Handles re-checking the exception specification if unexpectedHandler
 187 // throws, and if bad_exception needs to be thrown.  Called from the
 188 // compiler.
 189 extern "C" void __cxa_call_unexpected (void *) __attribute__((noreturn));
 190 extern "C" void __cxa_call_terminate (void*) __attribute__((noreturn));
 191
 192 #ifdef __ARM_EABI_UNWINDER__
 193 // Arm EABI specified routines.
 194 typedef enum {
 195   ctm_failed = 0,
 196   ctm_succeeded = 1,
 197   ctm_succeeded_with_ptr_to_base = 2
 198 } __cxa_type_match_result;
 199 extern "C" bool __cxa_type_match(_Unwind_Exception*, const std::type_info*,
 200                                  bool, void**);
 201 extern "C" void __cxa_begin_cleanup (_Unwind_Exception*);
 202 extern "C" void __cxa_end_cleanup (void);
 203 #endif
 204
 205 // Invokes given handler, dying appropriately if the user handler was
 206 // so inconsiderate as to return.
 207 extern void __terminate(std::terminate_handler) __attribute__((noreturn));
 208 extern void __unexpected(std::unexpected_handler) __attribute__((noreturn));
 209
 210 // The current installed user handlers.
 211 extern std::terminate_handler __terminate_handler;
 212 extern std::unexpected_handler __unexpected_handler;
 213
 214 // These are explicitly GNU C++ specific.
 215
 216 // Acquire the C++ exception header from the C++ object.
 217 static inline __cxa_exception *
 218 __get_exception_header_from_obj (void *ptr)
 219 {
 220   return reinterpret_cast<__cxa_exception *>(ptr) - 1;
 221 }
 222
 223 // Acquire the C++ exception header from the generic exception header.
 224 static inline __cxa_exception *
 225 __get_exception_header_from_ue (_Unwind_Exception *exc)
 226 {
 227   return reinterpret_cast<__cxa_exception *>(exc + 1) - 1;
 228 }
 229
 230 // Acquire the C++ refcounted exception header from the C++ object.
 231 static inline __cxa_refcounted_exception *
 232 __get_refcounted_exception_header_from_obj (void *ptr)
 233 {
 234   return reinterpret_cast<__cxa_refcounted_exception *>(ptr) - 1;
 235 }
 236
 237 // Acquire the C++ refcounted exception header from the generic exception
 238 // header.
 239 static inline __cxa_refcounted_exception *
 240 __get_refcounted_exception_header_from_ue (_Unwind_Exception *exc)
 241 {
 242   return reinterpret_cast<__cxa_refcounted_exception *>(exc + 1) - 1;
 243 }
 244
 245 static inline __cxa_dependent_exception *
 246 __get_dependent_exception_from_ue (_Unwind_Exception *exc)
 247 {
 248   return reinterpret_cast<__cxa_dependent_exception *>(exc + 1) - 1;
 249 }
 250
 251 #ifdef __ARM_EABI_UNWINDER__
 252 static inline bool
 253 __is_gxx_exception_class(_Unwind_Exception_Class c)
 254 {
 255   // TODO: Take advantage of the fact that c will always be word aligned.
 256   return c[0] == 'G'
 257          && c[1] == 'N'
 258          && c[2] == 'U'
 259          && c[3] == 'C'
 260          && c[4] == 'C'
 261          && c[5] == '+'
 262          && c[6] == '+'
 263          && (c[7] == '\0' || c[7] == '\x01');
 264 }
 265
 266 // Only checks for primary or dependent, but not that it is a C++ exception at
 267 // all.
 268 static inline bool
 269 __is_dependent_exception(_Unwind_Exception_Class c)
 270 {
 271   return c[7] == '\x01';
 272 }
 273
 274 static inline void
 275 __GXX_INIT_PRIMARY_EXCEPTION_CLASS(_Unwind_Exception_Class c)
 276 {
 277   c[0] = 'G';
 278   c[1] = 'N';
 279   c[2] = 'U';
 280   c[3] = 'C';
 281   c[4] = 'C';
 282   c[5] = '+';
 283   c[6] = '+';
 284   c[7] = '\0';
 285 }
 286
 287 static inline void
 288 __GXX_INIT_DEPENDENT_EXCEPTION_CLASS(_Unwind_Exception_Class c)
 289 {
 290   c[0] = 'G';
 291   c[1] = 'N';
 292   c[2] = 'U';
 293   c[3] = 'C';
 294   c[4] = 'C';
 295   c[5] = '+';
 296   c[6] = '+';
 297   c[7] = '\x01';
 298 }
 299
 300 static inline bool
 301 __is_gxx_forced_unwind_class(_Unwind_Exception_Class c)
 302 {
 303   return c[0] == 'G'
 304          && c[1] == 'N'
 305          && c[2] == 'U'
 306          && c[3] == 'C'
 307          && c[4] == 'F'
 308          && c[5] == 'O'
 309          && c[6] == 'R'
 310          && c[7] == '\0';
 311 }
 312
 313 static inline void
 314 __GXX_INIT_FORCED_UNWIND_CLASS(_Unwind_Exception_Class c)
 315 {
 316   c[0] = 'G';
 317   c[1] = 'N';
 318   c[2] = 'U';
 319   c[3] = 'C';
 320   c[4] = 'F';
 321   c[5] = 'O';
 322   c[6] = 'R';
 323   c[7] = '\0';
 324 }
 325
 326 static inline void*
 327 __gxx_caught_object(_Unwind_Exception* eo)
 328 {
 329   return (void*)eo->barrier_cache.bitpattern[0];
 330 }
 331 #else // !__ARM_EABI_UNWINDER__
 332 // This is the primary exception class we report -- "GNUCC++\0".
 333 const _Unwind_Exception_Class __gxx_primary_exception_class
 334 = ((((((((_Unwind_Exception_Class) 'G'
 335          << 8 | (_Unwind_Exception_Class) 'N')
 336         << 8 | (_Unwind_Exception_Class) 'U')
 337        << 8 | (_Unwind_Exception_Class) 'C')
 338       << 8 | (_Unwind_Exception_Class) 'C')
 339      << 8 | (_Unwind_Exception_Class) '+')
 340     << 8 | (_Unwind_Exception_Class) '+')
 341    << 8 | (_Unwind_Exception_Class) '\0');
 342
 343 // This is the dependent (from std::rethrow_exception) exception class we report
 344 // "GNUCC++\x01"
 345 const _Unwind_Exception_Class __gxx_dependent_exception_class
 346 = ((((((((_Unwind_Exception_Class) 'G'
 347          << 8 | (_Unwind_Exception_Class) 'N')
 348         << 8 | (_Unwind_Exception_Class) 'U')
 349        << 8 | (_Unwind_Exception_Class) 'C')
 350       << 8 | (_Unwind_Exception_Class) 'C')
 351      << 8 | (_Unwind_Exception_Class) '+')
 352     << 8 | (_Unwind_Exception_Class) '+')
 353    << 8 | (_Unwind_Exception_Class) '\x01');
 354
 355 static inline bool
 356 __is_gxx_exception_class(_Unwind_Exception_Class c)
 357 {
 358   return c == __gxx_primary_exception_class
 359       || c == __gxx_dependent_exception_class;
 360 }
 361
 362 // Only checks for primary or dependent, but not that it is a C++ exception at
 363 // all.
 364 static inline bool
 365 __is_dependent_exception(_Unwind_Exception_Class c)
 366 {
 367   return (c & 1);
 368 }
 369
 370 #define __GXX_INIT_PRIMARY_EXCEPTION_CLASS(c) c = __gxx_primary_exception_class
 371 #define __GXX_INIT_DEPENDENT_EXCEPTION_CLASS(c) \
 372   c = __gxx_dependent_exception_class
 373
 374 // GNU C++ personality routine, Version 0.
 375 extern "C" _Unwind_Reason_Code __gxx_personality_v0
 376      (int, _Unwind_Action, _Unwind_Exception_Class,
 377       struct _Unwind_Exception *, struct _Unwind_Context *);
 378
 379 // GNU C++ sjlj personality routine, Version 0.
 380 extern "C" _Unwind_Reason_Code __gxx_personality_sj0
 381      (int, _Unwind_Action, _Unwind_Exception_Class,
 382       struct _Unwind_Exception *, struct _Unwind_Context *);
 383
 384 static inline void*
 385 __gxx_caught_object(_Unwind_Exception* eo)
 386 {
 387   // Bad as it looks, this actually works for dependent exceptions too.
 388   __cxa_exception* header = __get_exception_header_from_ue (eo);
 389   return header->adjustedPtr;
 390 }
 391 #endif // !__ARM_EABI_UNWINDER__
 392
 393 static inline void*
 394 __get_object_from_ue(_Unwind_Exception* eo) throw()
 395 {
 396   return __is_dependent_exception (eo->exception_class) ?
 397     __get_dependent_exception_from_ue (eo)->primaryException :
 398     eo + 1;
 399 }
 400
 401 static inline void *
 402 __get_object_from_ambiguous_exception(__cxa_exception *p_or_d) throw()
 403 {
 404         return __get_object_from_ue (&p_or_d->unwindHeader);
 405 }
 406
 407
 408 } /* namespace __cxxabiv1 */
 409
 410 #pragma GCC visibility pop
 411
 412 #endif // _UNWIND_CXX_H