eh_catch.cc Source File

00001 // -*- C++ -*- Exception handling routines for catching.
00002 // Copyright (C) 2001 Free Software Foundation, Inc.
00003 //
00004 // This file is part of GNU CC.
00005 //
00006 // GNU CC is free software; you can redistribute it and/or modify
00007 // it under the terms of the GNU General Public License as published by
00008 // the Free Software Foundation; either version 2, or (at your option)
00009 // any later version.
00010 //
00011 // GNU CC is distributed in the hope that it will be useful,
00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014 // GNU General Public License for more details.
00015 //
00016 // You should have received a copy of the GNU General Public License
00017 // along with GNU CC; see the file COPYING.  If not, write to
00018 // the Free Software Foundation, 59 Temple Place - Suite 330,
00019 // Boston, MA 02111-1307, USA.
00020 
00021 // As a special exception, you may use this file as part of a free software
00022 // library without restriction.  Specifically, if other files instantiate
00023 // templates or use macros or inline functions from this file, or you compile
00024 // this file and link it with other files to produce an executable, this
00025 // file does not by itself cause the resulting executable to be covered by
00026 // the GNU General Public License.  This exception does not however
00027 // invalidate any other reasons why the executable file might be covered by
00028 // the GNU General Public License.
00029 
00030 
00031 #include <cstdlib>
00032 #include "unwind-cxx.h"
00033 
00034 using namespace __cxxabiv1;
00035 
00036 
00037 extern "C" void *
00038 __cxa_begin_catch (_Unwind_Exception *exceptionObject)
00039 {
00040   // ??? Foreign exceptions can't be stacked here, and there doesn't
00041   // appear to be any place to store for __cxa_end_catch to destroy.
00042 
00043   __cxa_exception *header = __get_exception_header_from_ue (exceptionObject);
00044   __cxa_eh_globals *globals = __cxa_get_globals ();
00045   __cxa_exception *prev = globals->caughtExceptions;
00046   int count = header->handlerCount;
00047 
00048   if (count < 0)
00049     // This exception was rethrown from an immediately enclosing region.
00050     count = -count + 1;
00051   else
00052     count += 1;
00053   header->handlerCount = count;
00054 
00055   globals->uncaughtExceptions -= 1;
00056   if (header != prev)
00057     {
00058       header->nextException = prev;
00059       globals->caughtExceptions = header;
00060     }
00061 
00062   return header->adjustedPtr;
00063 }
00064 
00065 
00066 extern "C" void
00067 __cxa_end_catch ()
00068 {
00069   __cxa_eh_globals *globals = __cxa_get_globals_fast ();
00070   __cxa_exception *header = globals->caughtExceptions;
00071   int count = header->handlerCount;
00072 
00073   if (count < 0)
00074     {
00075       // This exception was rethrown.  Decrement the (inverted) catch
00076       // count and remove it from the chain when it reaches zero.
00077       if (++count == 0)
00078     {
00079       globals->uncaughtExceptions += 1;
00080       globals->caughtExceptions = header->nextException;
00081     }
00082     }
00083   else if (--count == 0)
00084     {
00085       // Handling for this exception is complete.  Destroy the object.
00086       globals->caughtExceptions = header->nextException;
00087       _Unwind_DeleteException (&header->unwindHeader);
00088       return;
00089     }
00090   else if (count < 0)
00091     // A bug in the exception handling library or compiler.
00092     std::abort ();
00093 
00094   header->handlerCount = count;
00095 }
00096 
00097 
00098 bool
00099 std::uncaught_exception() throw()
00100 {
00101   __cxa_eh_globals *globals = __cxa_get_globals ();
00102   return globals->uncaughtExceptions != 0;
00103 }