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

   1 // -*- C++ -*- Exception handling routines for throwing.
   2 // Copyright (C) 2001-2020 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::
  57 __cxa_init_primary_exception(void *obj, std::type_info *tinfo,
  58                              void (_GLIBCXX_CDTOR_CALLABI *dest) (void *))
  59 _GLIBCXX_NOTHROW
  60 {
  61   __cxa_refcounted_exception *header
  62     = __get_refcounted_exception_header_from_obj (obj);
  63   header->referenceCount = 0;
  64   header->exc.exceptionType = tinfo;
  65   header->exc.exceptionDestructor = dest;
  66   header->exc.unexpectedHandler = std::get_unexpected ();
  67   header->exc.terminateHandler = std::get_terminate ();
  68   __GXX_INIT_PRIMARY_EXCEPTION_CLASS(header->exc.unwindHeader.exception_class);
  69   header->exc.unwindHeader.exception_cleanup = __gxx_exception_cleanup;
  70
  71   return header;
  72 }
  73
  74 extern "C" void
  75 __cxxabiv1::__cxa_throw (void *obj, std::type_info *tinfo,
  76                          void (_GLIBCXX_CDTOR_CALLABI *dest) (void *))
  77 {
  78   PROBE2 (throw, obj, tinfo);
  79
  80   __cxa_eh_globals *globals = __cxa_get_globals ();
  81   globals->uncaughtExceptions += 1;
  82   // Definitely a primary.
  83   __cxa_refcounted_exception *header =
  84     __cxa_init_primary_exception(obj, tinfo, dest);
  85   header->referenceCount = 1;
  86
  87 #ifdef __USING_SJLJ_EXCEPTIONS__
  88   _Unwind_SjLj_RaiseException (&header->exc.unwindHeader);
  89 #else
  90   _Unwind_RaiseException (&header->exc.unwindHeader);
  91 #endif
  92
  93   // Some sort of unwinding error.  Note that terminate is a handler.
  94   __cxa_begin_catch (&header->exc.unwindHeader);
  95   std::terminate ();
  96 }
  97
  98 extern "C" void
  99 __cxxabiv1::__cxa_rethrow ()
 100 {
 101   __cxa_eh_globals *globals = __cxa_get_globals ();
 102   __cxa_exception *header = globals->caughtExceptions;
 103
 104   globals->uncaughtExceptions += 1;
 105
 106   // Watch for luser rethrowing with no active exception.
 107   if (header)
 108     {
 109       // Tell __cxa_end_catch this is a rethrow.
 110       if (!__is_gxx_exception_class(header->unwindHeader.exception_class))
 111         globals->caughtExceptions = 0;
 112       else
 113         {
 114           header->handlerCount = -header->handlerCount;
 115           // Only notify probe for C++ exceptions.
 116           PROBE2 (rethrow, __get_object_from_ambiguous_exception(header),
 117                   header->exceptionType);
 118         }
 119
 120 #ifdef __USING_SJLJ_EXCEPTIONS__
 121       _Unwind_SjLj_Resume_or_Rethrow (&header->unwindHeader);
 122 #else
 123 #if defined(_LIBUNWIND_STD_ABI)
 124       _Unwind_RaiseException (&header->unwindHeader);
 125 #else
 126       _Unwind_Resume_or_Rethrow (&header->unwindHeader);
 127 #endif
 128 #endif
 129
 130       // Some sort of unwinding error.  Note that terminate is a handler.
 131       __cxa_begin_catch (&header->unwindHeader);
 132     }
 133   std::terminate ();
 134 }