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

   1 // -*- C++ -*- Exception handling routines for throwing.
   2 // Copyright (C) 2001-2016 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
  28 using namespace __cxxabiv1;
  29
  30
  31 static void
  32 __gxx_exception_cleanup (_Unwind_Reason_Code code, _Unwind_Exception *exc)
  33 {
  34   // This cleanup is set only for primaries.
  35   __cxa_refcounted_exception *header
  36     = __get_refcounted_exception_header_from_ue (exc);
  37
  38   // We only want to be called through _Unwind_DeleteException.
  39   // _Unwind_DeleteException in the HP-UX IA64 libunwind library
  40   // returns _URC_NO_REASON and not _URC_FOREIGN_EXCEPTION_CAUGHT
  41   // like the GCC _Unwind_DeleteException function does.
  42   if (code != _URC_FOREIGN_EXCEPTION_CAUGHT && code != _URC_NO_REASON)
  43     __terminate (header->exc.terminateHandler);
  44
  45 #if ATOMIC_INT_LOCK_FREE > 1
  46   if (__atomic_sub_fetch (&header->referenceCount, 1, __ATOMIC_ACQ_REL) == 0)
  47     {
  48 #endif
  49       if (header->exc.exceptionDestructor)
  50         header->exc.exceptionDestructor (header + 1);
  51
  52       __cxa_free_exception (header + 1);
  53 #if ATOMIC_INT_LOCK_FREE > 1
  54     }
  55 #endif
  56 }
  57
  58 extern "C" __cxa_refcounted_exception*
  59 __cxxabiv1::__cxa_init_primary_exception(void *obj, std::type_info *tinfo,
  60                                          void (_GLIBCXX_CDTOR_CALLABI *dest) (void *))
  61 {
  62   __cxa_refcounted_exception *header
  63     = __get_refcounted_exception_header_from_obj (obj);
  64   header->referenceCount = 0;
  65   header->exc.exceptionType = tinfo;
  66   header->exc.exceptionDestructor = dest;
  67   header->exc.unexpectedHandler = std::get_unexpected ();
  68   header->exc.terminateHandler = std::get_terminate ();
  69   __GXX_INIT_PRIMARY_EXCEPTION_CLASS(header->exc.unwindHeader.exception_class);
  70   header->exc.unwindHeader.exception_cleanup = __gxx_exception_cleanup;
  71
  72   return header;
  73 }
  74
  75 extern "C" void
  76 __cxxabiv1::__cxa_throw (void *obj, std::type_info *tinfo,
  77                          void (_GLIBCXX_CDTOR_CALLABI *dest) (void *))
  78 {
  79   PROBE2 (throw, obj, tinfo);
  80
  81   __cxa_eh_globals *globals = __cxa_get_globals ();
  82   globals->uncaughtExceptions += 1;
  83   // Definitely a primary.
  84   __cxa_refcounted_exception *header =
  85     __cxa_init_primary_exception(obj, tinfo, dest);
  86   header->referenceCount = 1;
  87
  88 #ifdef __USING_SJLJ_EXCEPTIONS__
  89   _Unwind_SjLj_RaiseException (&header->exc.unwindHeader);
  90 #else
  91   _Unwind_RaiseException (&header->exc.unwindHeader);
  92 #endif
  93
  94   // Some sort of unwinding error.  Note that terminate is a handler.
  95   __cxa_begin_catch (&header->exc.unwindHeader);
  96   std::terminate ();
  97 }
  98
  99 extern "C" void
 100 __cxxabiv1::__cxa_rethrow ()
 101 {
 102   __cxa_eh_globals *globals = __cxa_get_globals ();
 103   __cxa_exception *header = globals->caughtExceptions;
 104
 105   globals->uncaughtExceptions += 1;
 106
 107   // Watch for luser rethrowing with no active exception.
 108   if (header)
 109     {
 110       // Tell __cxa_end_catch this is a rethrow.
 111       if (!__is_gxx_exception_class(header->unwindHeader.exception_class))
 112         globals->caughtExceptions = 0;
 113       else
 114         {
 115           header->handlerCount = -header->handlerCount;
 116           // Only notify probe for C++ exceptions.
 117           PROBE2 (rethrow, __get_object_from_ambiguous_exception(header),
 118                   header->exceptionType);
 119         }
 120
 121 #ifdef __USING_SJLJ_EXCEPTIONS__
 122       _Unwind_SjLj_Resume_or_Rethrow (&header->unwindHeader);
 123 #else
 124 #if defined(_LIBUNWIND_STD_ABI)
 125       _Unwind_RaiseException (&header->unwindHeader);
 126 #else
 127       _Unwind_Resume_or_Rethrow (&header->unwindHeader);
 128 #endif
 129 #endif
 130
 131       // Some sort of unwinding error.  Note that terminate is a handler.
 132       __cxa_begin_catch (&header->unwindHeader);
 133     }
 134   std::terminate ();
 135 }