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

   1 // -*- C++ -*- Helpers for calling unextected and terminate
   2 // Copyright (C) 2001-2018 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 3, 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 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 #include <bits/c++config.h>
  26 #include <cstdlib>
  27 #include <bits/exception_defines.h>
  28 #include "unwind-cxx.h"
  29
  30 using namespace __cxxabiv1;
  31
  32 #include "unwind-pe.h"
  33
  34
  35 // Helper routine for when the exception handling code needs to call
  36 // terminate.
  37
  38 extern "C" void
  39 __cxa_call_terminate(_Unwind_Exception* ue_header) throw ()
  40 {
  41
  42   if (ue_header)
  43     {
  44       // terminate is classed as a catch handler.
  45       __cxa_begin_catch(ue_header);
  46
  47       // Call the terminate handler that was in effect when we threw this
  48       // exception.  */
  49       if (__is_gxx_exception_class(ue_header->exception_class))
  50         {
  51           __cxa_exception* xh;
  52
  53           xh = __get_exception_header_from_ue(ue_header);
  54           __terminate(xh->terminateHandler);
  55         }
  56     }
  57   /* Call the global routine if we don't have anything better.  */
  58   std::terminate();
  59 }
  60
  61
  62 #ifdef __ARM_EABI_UNWINDER__
  63 // The ARM EABI __cxa_call_unexpected has the same semantics as the generic
  64 // routine, but the exception specification has a different format.
  65 extern "C" void
  66 __cxa_call_unexpected(void* exc_obj_in)
  67 {
  68   _Unwind_Exception* exc_obj
  69     = reinterpret_cast<_Unwind_Exception*>(exc_obj_in);
  70
  71   int rtti_count = 0;
  72   _Unwind_Word rtti_stride = 0;
  73   _Unwind_Word* rtti_list = NULL;
  74   _Unwind_Ptr rtti_base = 0;
  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       rtti_base = (_Unwind_Ptr) exc_obj->barrier_cache.bitpattern[2];
  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_typeinfo_ptr(rtti_base, 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 the exception spec allows std::bad_exception, throw that.
 144           // We don't have a thrown object to compare against, but since
 145           // bad_exception doesn't have virtual bases, that's OK; just pass NULL.
 146           void* obj = NULL;
 147           if (catch_type->__do_catch(&bad_exc, &obj, 1))
 148             bad_exception_allowed = true;
 149         }
 150
 151       // If the exception spec allows std::bad_exception, throw that.
 152 #if __cpp_exceptions
 153       if (bad_exception_allowed)
 154         throw std::bad_exception();
 155 #endif
 156
 157       // Otherwise, die.
 158       __terminate(terminateHandler);
 159     }
 160 }
 161 #endif // __ARM_EABI_UNWINDER__