libstdc++-v3/libsupc++/eh_call.cc

   1 // -*- C++ -*- Helpers for calling unextected and terminate
   2 // Copyright (C) 2001, 2002, 2003 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 2, 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 // You should have received a copy of the GNU General Public License
  17 // along with GCC; 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 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30
  31 #include <bits/c++config.h>
  32 #include <cstdlib>
  33 #include <exception_defines.h>
  34 #include "unwind-cxx.h"
  35
  36 using namespace __cxxabiv1;
  37
  38 #include "unwind-pe.h"
  39
  40
  41 // Helper routine for when the exception handling code needs to call
  42 // terminate.
  43
  44 extern "C" void
  45 __cxa_call_terminate(_Unwind_Exception* ue_header)
  46 {
  47
  48   if (ue_header)
  49     {
  50       // terminate is classed as a catch handler.
  51       __cxa_begin_catch(ue_header);
  52
  53       // Call the terminate handler that was in effect when we threw this
  54       // exception.  */
  55       if (__is_gxx_exception_class(ue_header->exception_class))
  56         {
  57           __cxa_exception* xh;
  58
  59           xh = __get_exception_header_from_ue(ue_header);
  60           __terminate(xh->terminateHandler);
  61         }
  62     }
  63   /* Call the global routine if we don't have anything better.  */
  64   std::terminate();
  65 }
  66
  67
  68 #ifdef __ARM_EABI_UNWINDER__
  69 // The ARM EABI __cxa_call_unexpected has the same semantics as the generic
  70 // routine, but the exception specification has a different format.
  71 extern "C" void
  72 __cxa_call_unexpected(void* exc_obj_in)
  73 {
  74   _Unwind_Exception* exc_obj
  75     = reinterpret_cast<_Unwind_Exception*>(exc_obj_in);
  76
  77   int rtti_count = 0;
  78   _Unwind_Word rtti_stride = 0;
  79   _Unwind_Word* rtti_list = NULL;
  80   bool foreign_exception;
  81   std::unexpected_handler unexpectedHandler = NULL;
  82   std::terminate_handler terminateHandler = NULL;
  83   __cxa_exception* xh;
  84   if (__is_gxx_exception_class(exc_obj->exception_class))
  85     {
  86       // Save data from the EO, which may be clobbered by _cxa_begin_catch.
  87       xh = __get_exception_header_from_ue(exc_obj);
  88       unexpectedHandler = xh->unexpectedHandler;
  89       terminateHandler = xh->terminateHandler;
  90       rtti_count = exc_obj->barrier_cache.bitpattern[1];
  91
  92       rtti_stride = exc_obj->barrier_cache.bitpattern[3];
  93       rtti_list = (_Unwind_Word*) exc_obj->barrier_cache.bitpattern[4];
  94       foreign_exception = false;
  95     }
  96   else
  97     foreign_exception = true;
  98
  99   /* This must be called after extracting data from the EO, but before
 100      calling unexpected().   */
 101   __cxa_begin_catch(exc_obj);
 102
 103   // This function is a handler for our exception argument.  If we exit
 104   // by throwing a different exception, we'll need the original cleaned up.
 105   struct end_catch_protect
 106   {
 107     end_catch_protect() { }
 108     ~end_catch_protect() { __cxa_end_catch(); }
 109   } end_catch_protect_obj;
 110
 111
 112   try
 113     {
 114       if (foreign_exception)
 115         std::unexpected();
 116       else
 117         __unexpected(unexpectedHandler);
 118     }
 119   catch(...)
 120     {
 121       /* See if the new exception matches the rtti list.  */
 122       if (foreign_exception)
 123         std::terminate();
 124
 125       // Get the exception thrown from unexpected.
 126
 127       __cxa_eh_globals* globals = __cxa_get_globals_fast();
 128       __cxa_exception* new_xh = globals->caughtExceptions;
 129       void* new_ptr = new_xh + 1;
 130       const std::type_info* catch_type;
 131       int n;
 132       bool bad_exception_allowed = false;
 133       const std::type_info& bad_exc = typeid(std::bad_exception);
 134
 135       // Check the new exception against the rtti list
 136       for (n = 0; n < rtti_count; n++)
 137         {
 138           _Unwind_Word offset;
 139
 140           offset = (_Unwind_Word) &rtti_list[n * (rtti_stride >> 2)];
 141           offset = _Unwind_decode_target2(offset);
 142           catch_type = (const std::type_info*) (offset);
 143
 144           if (__cxa_type_match(&new_xh->unwindHeader, catch_type, false,
 145                                &new_ptr) != ctm_failed)
 146             __throw_exception_again;
 147
 148           if (catch_type->__do_catch(&bad_exc, 0, 1))
 149             bad_exception_allowed = true;
 150         }
 151
 152       // If the exception spec allows std::bad_exception, throw that.
 153 #ifdef __EXCEPTIONS
 154       if (bad_exception_allowed)
 155         throw std::bad_exception();
 156 #endif
 157
 158       // Otherwise, die.
 159       __terminate(terminateHandler);
 160     }
 161 }
 162 #endif // __ARM_EABI_UNWINDER__