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

   1 // -*- C++ -*- Exception handling routines for throwing.
   2 // Copyright (C) 2001-2017 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 "unwind-cxx.h"
  27 #include "eh_atomics.h"
  28
  29 using namespace __cxxabiv1;
  30
  31
  32 static void
  33 __gxx_exception_cleanup (_Unwind_Reason_Code code, _Unwind_Exception *exc)
  34 {
  35   // This cleanup is set only for primaries.
  36   __cxa_refcounted_exception *header
  37     = __get_refcounted_exception_header_from_ue (exc);
  38
  39   // We only want to be called through _Unwind_DeleteException.
  40   // _Unwind_DeleteException in the HP-UX IA64 libunwind library
  41   // returns _URC_NO_REASON and not _URC_FOREIGN_EXCEPTION_CAUGHT
  42   // like the GCC _Unwind_DeleteException function does.
  43   if (code != _URC_FOREIGN_EXCEPTION_CAUGHT && code != _URC_NO_REASON)
  44     __terminate (header->exc.terminateHandler);
  45
  46   if (__gnu_cxx::__eh_atomic_dec (&header->referenceCount))
  47     {
  48       if (header->exc.exceptionDestructor)
  49         header->exc.exceptionDestructor (header + 1);
  50
  51       __cxa_free_exception (header + 1);
  52     }
  53 }
  54
  55 extern "C" __cxa_refcounted_exception*
  56 __cxxabiv1::__cxa_init_primary_exception(void *obj, std::type_info *tinfo,
  57                                          void (_GLIBCXX_CDTOR_CALLABI *dest) (void *))
  58 {
  59   __cxa_refcounted_exception *header
  60     = __get_refcounted_exception_header_from_obj (obj);
  61   header->referenceCount = 0;
  62   header->exc.exceptionType = tinfo;
  63   header->exc.exceptionDestructor = dest;
  64   header->exc.unexpectedHandler = std::get_unexpected ();
  65   header->exc.terminateHandler = std::get_terminate ();
  66   __GXX_INIT_PRIMARY_EXCEPTION_CLASS(header->exc.unwindHeader.exception_class);
  67   header->exc.unwindHeader.exception_cleanup = __gxx_exception_cleanup;
  68
  69   return header;
  70 }
  71
  72 extern "C" void
  73 __cxxabiv1::__cxa_throw (void *obj, std::type_info *tinfo,
  74                          void (_GLIBCXX_CDTOR_CALLABI *dest) (void *))
  75 {
  76   PROBE2 (throw, obj, tinfo);
  77
  78   __cxa_eh_globals *globals = __cxa_get_globals ();
  79   globals->uncaughtExceptions += 1;
  80   // Definitely a primary.
  81   __cxa_refcounted_exception *header =
  82     __cxa_init_primary_exception(obj, tinfo, dest);
  83   header->referenceCount = 1;
  84
  85 #ifdef __USING_SJLJ_EXCEPTIONS__
  86   _Unwind_SjLj_RaiseException (&header->exc.unwindHeader);
  87 #else
  88   _Unwind_RaiseException (&header->exc.unwindHeader);
  89 #endif
  90
  91   // Some sort of unwinding error.  Note that terminate is a handler.
  92   __cxa_begin_catch (&header->exc.unwindHeader);
  93   std::terminate ();
  94 }
  95
  96 extern "C" void
  97 __cxxabiv1::__cxa_rethrow ()
  98 {
  99   __cxa_eh_globals *globals = __cxa_get_globals ();
 100   __cxa_exception *header = globals->caughtExceptions;
 101
 102   globals->uncaughtExceptions += 1;
 103
 104   // Watch for luser rethrowing with no active exception.
 105   if (header)
 106     {
 107       // Tell __cxa_end_catch this is a rethrow.
 108       if (!__is_gxx_exception_class(header->unwindHeader.exception_class))
 109         globals->caughtExceptions = 0;
 110       else
 111         {
 112           header->handlerCount = -header->handlerCount;
 113           // Only notify probe for C++ exceptions.
 114           PROBE2 (rethrow, __get_object_from_ambiguous_exception(header),
 115                   header->exceptionType);
 116         }
 117
 118 #ifdef __USING_SJLJ_EXCEPTIONS__
 119       _Unwind_SjLj_Resume_or_Rethrow (&header->unwindHeader);
 120 #else
 121 #if defined(_LIBUNWIND_STD_ABI)
 122       _Unwind_RaiseException (&header->unwindHeader);
 123 #else
 124       _Unwind_Resume_or_Rethrow (&header->unwindHeader);
 125 #endif
 126 #endif
 127
 128       // Some sort of unwinding error.  Note that terminate is a handler.
 129       __cxa_begin_catch (&header->unwindHeader);
 130     }
 131   std::terminate ();
 132 }