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

   1 // -*- C++ -*- Exception handling and frame unwind runtime interface routines.
   2 // Copyright (C) 2001 Free Software Foundation, Inc.
   3 //
   4 // This file is part of GNU CC.
   5 //
   6 // GNU CC 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 2, or (at your option)
   9 // any later version.
  10 //
  11 // GNU CC 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 // You should have received a copy of the GNU General Public License
  17 // along with GNU CC; see the file COPYING.  If not, write to
  18 // the Free Software Foundation, 59 Temple Place - Suite 330,
  19 // Boston, MA 02111-1307, USA.
  20
  21 // This is derived from the C++ ABI for IA-64.  Where we diverge
  22 // for cross-architecture compatibility are noted with "@@@".
  23
  24 #ifndef __UNWIND_CXX_H
  25 #define __UNWIND_CXX_H 1
  26
  27 // Level 2: C++ ABI
  28
  29 #include <typeinfo>
  30 #include <exception>
  31 #include <cstddef>
  32 #include "unwind.h"
  33
  34 namespace __cxxabiv1
  35 {
  36
  37 // A C++ exception object consists of a header, which is a wrapper around
  38 // an unwind object header with additional C++ specific information,
  39 // followed by the exception object itself.
  40
  41 struct __cxa_exception
  42 {
  43   // Manage the exception object itself.
  44   std::type_info *exceptionType;
  45   void (*exceptionDestructor)(void *);
  46
  47   // The C++ standard has entertaining rules wrt calling set_terminate
  48   // and set_unexpected in the middle of the exception cleanup process.
  49   std::unexpected_handler unexpectedHandler;
  50   std::terminate_handler terminateHandler;
  51
  52   // The caught exception stack threads through here.
  53   __cxa_exception *nextException;
  54
  55   // How many nested handlers have caught this exception.  A negated
  56   // value is a signal that this object has been rethrown.
  57   int handlerCount;
  58
  59   // Cache parsed handler data from the personality routine Phase 1
  60   // for Phase 2 and __cxa_call_unexpected.
  61   int handlerSwitchValue;
  62   const unsigned char *actionRecord;
  63   const unsigned char *languageSpecificData;
  64   void *catchTemp;
  65   void *adjustedPtr;
  66
  67   // The generic exception header.  Must be last.
  68   _Unwind_Exception unwindHeader;
  69 };
  70
  71 // Each thread in a C++ program has access to a __cxa_eh_globals object.
  72 struct __cxa_eh_globals
  73 {
  74   __cxa_exception *caughtExceptions;
  75   unsigned int uncaughtExceptions;
  76 };
  77
  78
  79 // The __cxa_eh_globals for the current thread can be obtained by using
  80 // either of the following functions.  The "fast" version assumes at least
  81 // one prior call of __cxa_get_globals has been made from the current
  82 // thread, so no initialization is necessary.
  83 extern "C" __cxa_eh_globals *__cxa_get_globals () throw();
  84 extern "C" __cxa_eh_globals *__cxa_get_globals_fast () throw();
  85
  86 // Allocate memory for the exception plus the thown object.
  87 extern "C" void *__cxa_allocate_exception(std::size_t thrown_size) throw();
  88
  89 // Free the space allocated for the exception.
  90 extern "C" void __cxa_free_exception(void *thrown_exception) throw();
  91
  92 // Throw the exception.
  93 extern "C" void __cxa_throw (void *thrown_exception,
  94                              std::type_info *tinfo,
  95                              void (*dest) (void *))
  96      __attribute__((noreturn));
  97
  98 // Used to implement exception handlers.
  99 extern "C" void *__cxa_begin_catch (_Unwind_Exception *) throw();
 100 extern "C" void __cxa_end_catch ();
 101 extern "C" void __cxa_rethrow () __attribute__((noreturn));
 102
 103 // These facilitate code generation for recurring situations.
 104 extern "C" void __cxa_bad_cast ();
 105 extern "C" void __cxa_bad_typeid ();
 106
 107 // @@@ These are not directly specified by the IA-64 C++ ABI.
 108
 109 // Handles re-checking the exception specification if unexpectedHandler
 110 // throws, and if bad_exception needs to be thrown.  Called from the
 111 // compiler.
 112 extern "C" void __cxa_call_unexpected (_Unwind_Exception *)
 113      __attribute__((noreturn));
 114
 115 // Invokes given handler, dying appropriately if the user handler was
 116 // so inconsiderate as to return.
 117 extern void __terminate(std::terminate_handler) __attribute__((noreturn));
 118 extern void __unexpected(std::unexpected_handler) __attribute__((noreturn));
 119
 120 // The current installed user handlers.
 121 extern std::terminate_handler __terminate_handler;
 122 extern std::unexpected_handler __unexpected_handler;
 123
 124 // These are explicitly GNU C++ specific.
 125
 126 // This is the exception class we report -- "GNUCC++\0".
 127 const _Unwind_Exception_Class __gxx_exception_class
 128 = ((((((((_Unwind_Exception_Class) 'G'
 129          << 8 | (_Unwind_Exception_Class) 'N')
 130         << 8 | (_Unwind_Exception_Class) 'U')
 131        << 8 | (_Unwind_Exception_Class) 'C')
 132       << 8 | (_Unwind_Exception_Class) 'C')
 133      << 8 | (_Unwind_Exception_Class) '+')
 134     << 8 | (_Unwind_Exception_Class) '+')
 135    << 8 | (_Unwind_Exception_Class) '\0');
 136
 137 // GNU C++ personality routine, Version 0.
 138 extern "C" _Unwind_Reason_Code __gxx_personality_v0
 139      (int, _Unwind_Action, _Unwind_Exception_Class,
 140       struct _Unwind_Exception *, struct _Unwind_Context *);
 141
 142 // GNU C++ sjlj personality routine, Version 0.
 143 extern "C" _Unwind_Reason_Code __gxx_personality_sj0
 144      (int, _Unwind_Action, _Unwind_Exception_Class,
 145       struct _Unwind_Exception *, struct _Unwind_Context *);
 146
 147 // Acquire the C++ exception header from the C++ object.
 148 static inline __cxa_exception *
 149 __get_exception_header_from_obj (void *ptr)
 150 {
 151   return reinterpret_cast<__cxa_exception *>(ptr) - 1;
 152 }
 153
 154 // Acquire the C++ exception header from the generic exception header.
 155 static inline __cxa_exception *
 156 __get_exception_header_from_ue (_Unwind_Exception *exc)
 157 {
 158   return reinterpret_cast<__cxa_exception *>(exc + 1) - 1;
 159 }
 160
 161 } /* namespace __cxxabiv1 */
 162
 163 #endif // __UNWIND_CXX_H