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 // 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 #include <bits/c++config.h>
  27 #include <cstdlib>
  28 #include <exception_defines.h>
  29 #include "unwind-cxx.h"
  30
  31 using namespace __cxxabiv1;
  32
  33 #include "unwind-pe.h"
  34
  35
  36 // Helper routine for when the exception handling code needs to call
  37 // terminate.
  38
  39 extern "C" void
  40 __cxa_call_terminate(_Unwind_Exception* ue_header) throw ()
  41 {
  42
  43   if (ue_header)
  44     {
  45       // terminate is classed as a catch handler.
  46       __cxa_begin_catch(ue_header);
  47
  48       // Call the terminate handler that was in effect when we threw this
  49       // exception.  */
  50       if (__is_gxx_exception_class(ue_header->exception_class))
  51         {
  52           __cxa_exception* xh;
  53
  54           xh = __get_exception_header_from_ue(ue_header);
  55           __terminate(xh->terminateHandler);
  56         }
  57     }
  58   /* Call the global routine if we don't have anything better.  */
  59   std::terminate();
  60 }
  61
  62
  63 #ifdef __ARM_EABI_UNWINDER__
  64 // The ARM EABI __cxa_call_unexpected has the same semantics as the generic
  65 // routine, but the exception specification has a different format.
  66 extern "C" void
  67 __cxa_call_unexpected(void* exc_obj_in)
  68 {
  69   _Unwind_Exception* exc_obj
  70     = reinterpret_cast<_Unwind_Exception*>(exc_obj_in);
  71
  72   int rtti_count = 0;
  73   _Unwind_Word rtti_stride = 0;
  74   _Unwind_Word* rtti_list = NULL;
  75   bool foreign_exception;
  76   std::unexpected_handler unexpectedHandler = NULL;
  77   std::terminate_handler terminateHandler = NULL;
  78   __cxa_exception* xh;
  79   if (__is_gxx_exception_class(exc_obj->exception_class))
  80     {
  81       // Save data from the EO, which may be clobbered by _cxa_begin_catch.
  82       xh = __get_exception_header_from_ue(exc_obj);
  83       unexpectedHandler = xh->unexpectedHandler;
  84       terminateHandler = xh->terminateHandler;
  85       rtti_count = exc_obj->barrier_cache.bitpattern[1];
  86
  87       rtti_stride = exc_obj->barrier_cache.bitpattern[3];
  88       rtti_list = (_Unwind_Word*) exc_obj->barrier_cache.bitpattern[4];
  89       foreign_exception = false;
  90     }
  91   else
  92     foreign_exception = true;
  93
  94   /* This must be called after extracting data from the EO, but before
  95      calling unexpected().   */
  96   __cxa_begin_catch(exc_obj);
  97
  98   // This function is a handler for our exception argument.  If we exit
  99   // by throwing a different exception, we'll need the original cleaned up.
 100   struct end_catch_protect
 101   {
 102     end_catch_protect() { }
 103     ~end_catch_protect() { __cxa_end_catch(); }
 104   } end_catch_protect_obj;
 105
 106
 107   __try
 108     {
 109       if (foreign_exception)
 110         std::unexpected();
 111       else
 112         __unexpected(unexpectedHandler);
 113     }
 114   __catch(...)
 115     {
 116       /* See if the new exception matches the rtti list.  */
 117       if (foreign_exception)
 118         std::terminate();
 119
 120       // Get the exception thrown from unexpected.
 121
 122       __cxa_eh_globals* globals = __cxa_get_globals_fast();
 123       __cxa_exception* new_xh = globals->caughtExceptions;
 124       void* new_ptr = __get_object_from_ambiguous_exception (new_xh);
 125       const std::type_info* catch_type;
 126       int n;
 127       bool bad_exception_allowed = false;
 128       const std::type_info& bad_exc = typeid(std::bad_exception);
 129
 130       // Check the new exception against the rtti list
 131       for (n = 0; n < rtti_count; n++)
 132         {
 133           _Unwind_Word offset;
 134
 135           offset = (_Unwind_Word) &rtti_list[n * (rtti_stride >> 2)];
 136           offset = _Unwind_decode_target2(offset);
 137           catch_type = (const std::type_info*) (offset);
 138
 139           if (__cxa_type_match(&new_xh->unwindHeader, catch_type, false,
 140                                &new_ptr) != ctm_failed)
 141             __throw_exception_again;
 142
 143           if (catch_type->__do_catch(&bad_exc, 0, 1))
 144             bad_exception_allowed = true;
 145         }
 146
 147       // If the exception spec allows std::bad_exception, throw that.
 148 #ifdef __EXCEPTIONS
 149       if (bad_exception_allowed)
 150         throw std::bad_exception();
 151 #endif
 152
 153       // Otherwise, die.
 154       __terminate(terminateHandler);
 155     }
 156 }
 157 #endif // __ARM_EABI_UNWINDER__