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

   1 // -*- C++ -*- Helpers for calling unextected and terminate
   2 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
   3 // 2011
   4 // Free Software Foundation, Inc.
   5 //
   6 // This file is part of GCC.
   7 //
   8 // GCC is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3, or (at your option)
  11 // any later version.
  12 //
  13 // GCC is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17 //
  18 // Under Section 7 of GPL version 3, you are granted additional
  19 // permissions described in the GCC Runtime Library Exception, version
  20 // 3.1, as published by the Free Software Foundation.
  21
  22 // You should have received a copy of the GNU General Public License and
  23 // a copy of the GCC Runtime Library Exception along with this program;
  24 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  25 // <http://www.gnu.org/licenses/>.
  26
  27 #include <bits/c++config.h>
  28 #include <cstdlib>
  29 #include <bits/exception_defines.h>
  30 #include "unwind-cxx.h"
  31
  32 using namespace __cxxabiv1;
  33
  34 #include "unwind-pe.h"
  35
  36
  37 // Helper routine for when the exception handling code needs to call
  38 // terminate.
  39
  40 extern "C" void
  41 __cxa_call_terminate(_Unwind_Exception* ue_header) throw ()
  42 {
  43
  44   if (ue_header)
  45     {
  46       // terminate is classed as a catch handler.
  47       __cxa_begin_catch(ue_header);
  48
  49       // Call the terminate handler that was in effect when we threw this
  50       // exception.  */
  51       if (__is_gxx_exception_class(ue_header->exception_class))
  52         {
  53           __cxa_exception* xh;
  54
  55           xh = __get_exception_header_from_ue(ue_header);
  56           __terminate(xh->terminateHandler);
  57         }
  58     }
  59   /* Call the global routine if we don't have anything better.  */
  60   std::terminate();
  61 }
  62
  63
  64 #ifdef __ARM_EABI_UNWINDER__
  65 // The ARM EABI __cxa_call_unexpected has the same semantics as the generic
  66 // routine, but the exception specification has a different format.
  67 extern "C" void
  68 __cxa_call_unexpected(void* exc_obj_in)
  69 {
  70   _Unwind_Exception* exc_obj
  71     = reinterpret_cast<_Unwind_Exception*>(exc_obj_in);
  72
  73   int rtti_count = 0;
  74   _Unwind_Word rtti_stride = 0;
  75   _Unwind_Word* rtti_list = NULL;
  76   bool foreign_exception;
  77   std::unexpected_handler unexpectedHandler = NULL;
  78   std::terminate_handler terminateHandler = NULL;
  79   __cxa_exception* xh;
  80   if (__is_gxx_exception_class(exc_obj->exception_class))
  81     {
  82       // Save data from the EO, which may be clobbered by _cxa_begin_catch.
  83       xh = __get_exception_header_from_ue(exc_obj);
  84       unexpectedHandler = xh->unexpectedHandler;
  85       terminateHandler = xh->terminateHandler;
  86       rtti_count = exc_obj->barrier_cache.bitpattern[1];
  87
  88       rtti_stride = exc_obj->barrier_cache.bitpattern[3];
  89       rtti_list = (_Unwind_Word*) exc_obj->barrier_cache.bitpattern[4];
  90       foreign_exception = false;
  91     }
  92   else
  93     foreign_exception = true;
  94
  95   /* This must be called after extracting data from the EO, but before
  96      calling unexpected().   */
  97   __cxa_begin_catch(exc_obj);
  98
  99   // This function is a handler for our exception argument.  If we exit
 100   // by throwing a different exception, we'll need the original cleaned up.
 101   struct end_catch_protect
 102   {
 103     end_catch_protect() { }
 104     ~end_catch_protect() { __cxa_end_catch(); }
 105   } end_catch_protect_obj;
 106
 107
 108   __try
 109     {
 110       if (foreign_exception)
 111         std::unexpected();
 112       else
 113         __unexpected(unexpectedHandler);
 114     }
 115   __catch(...)
 116     {
 117       /* See if the new exception matches the rtti list.  */
 118       if (foreign_exception)
 119         std::terminate();
 120
 121       // Get the exception thrown from unexpected.
 122
 123       __cxa_eh_globals* globals = __cxa_get_globals_fast();
 124       __cxa_exception* new_xh = globals->caughtExceptions;
 125       void* new_ptr = __get_object_from_ambiguous_exception (new_xh);
 126       const std::type_info* catch_type;
 127       int n;
 128       bool bad_exception_allowed = false;
 129       const std::type_info& bad_exc = typeid(std::bad_exception);
 130
 131       // Check the new exception against the rtti list
 132       for (n = 0; n < rtti_count; n++)
 133         {
 134           _Unwind_Word offset;
 135
 136           offset = (_Unwind_Word) &rtti_list[n * (rtti_stride >> 2)];
 137           offset = _Unwind_decode_target2(offset);
 138           catch_type = (const std::type_info*) (offset);
 139
 140           if (__cxa_type_match(&new_xh->unwindHeader, catch_type, false,
 141                                &new_ptr) != ctm_failed)
 142             __throw_exception_again;
 143
 144           if (catch_type->__do_catch(&bad_exc, 0, 1))
 145             bad_exception_allowed = true;
 146         }
 147
 148       // If the exception spec allows std::bad_exception, throw that.
 149 #ifdef __EXCEPTIONS
 150       if (bad_exception_allowed)
 151         throw std::bad_exception();
 152 #endif
 153
 154       // Otherwise, die.
 155       __terminate(terminateHandler);
 156     }
 157 }
 158 #endif // __ARM_EABI_UNWINDER__