Re: libstdc++/9756: __verbose_terminate_handler enters infinite loop

[Phil Edwards <phil@jaj.com>]

The following reply was made to PR libstdc++/9756; it has been noted by GNATS.

From: Phil Edwards <phil@jaj.com>
To: "Stephen M. Webb" <stephenw@cryptocard.com>
Cc: gcc-gnats@gcc.gnu.org
Subject: Re: libstdc++/9756: __verbose_terminate_handler enters infinite loop
Date: Thu, 20 Feb 2003 11:25:08 -0500

 On Thu, Feb 20, 2003 at 11:01:23AM -0500, Stephen M. Webb wrote:
 > On February 19, 2003 05:04 pm, Phil Edwards wrote:
 > > > >How-To-Repeat:
 > > >
 > > > echo "int main() { throw 0; }" > dc.cpp
 > > > g++ -o dc dc.cpp
 > > > ./dc
 > > > ^C
 > >
 > > I can't reproduce this.
 > 
 > I can't see how it's anything unique I've done, since gcc was built from 
 > unmodified CVS sources for both my 3.2 and 3.4 versions.  Is it possible the 
 > problem comes from binutils (I'm using 2.13.90 20021125 for gcc 3.4) or libc 
 > (I have 2.2.5)?
 
 Possibly, yes.
 
 
 > When I compile with gcc 3.2, I get expected behaviour:
 
 The sources have changed since then; in 3.2 we simply died.  Now the
 verbose termination routine is on by default.
 
 
 > ....
 > #10212 0x400ace0d in __cxa_rethrow () at 
 > /home/stephenw/gnu/gcc/libstdc++-v3/libsupc++/eh_throw.cc:104
 > #10213 0x400af034 in __gnu_cxx::__verbose_terminate_handler() ()
 >     at /home/stephenw/gnu/gcc/libstdc++-v3/libsupc++/vterminate.cc:81
 > #10214 0x400acbf5 in __cxxabiv1::__terminate(void (*)()) (
 >     handler=0x400aef50 <__gnu_cxx::__verbose_terminate_handler()>)
 >     at /home/stephenw/gnu/gcc/libstdc++-v3/libsupc++/eh_terminate.cc:43
 > #10215 0x400acc32 in std::terminate() () at 
 > /home/stephenw/gnu/gcc/libstdc++-v3/libsupc++/eh_terminate.cc:53
 > #10216 0x400ace0d in __cxa_rethrow () at 
 > /home/stephenw/gnu/gcc/libstdc++-v3/libsupc++/eh_throw.cc:104
 > #10217 0x400af034 in __gnu_cxx::__verbose_terminate_handler() ()
 >     at /home/stephenw/gnu/gcc/libstdc++-v3/libsupc++/vterminate.cc:81
 > #10218 0x400acbf5 in __cxxabiv1::__terminate(void (*)()) (
 >     handler=0x400aef50 <__gnu_cxx::__verbose_terminate_handler()>)
 >     at /home/stephenw/gnu/gcc/libstdc++-v3/libsupc++/eh_terminate.cc:43
 > #10219 0x400acc32 in std::terminate() () at 
 > /home/stephenw/gnu/gcc/libstdc++-v3/libsupc++/eh_terminate.cc:53
 > #10220 0x400acdc2 in __cxa_throw (obj=0x400b7d59, tinfo=0x2d, dest=0x2d)
 >     at /home/stephenw/gnu/gcc/libstdc++-v3/libsupc++/eh_throw.cc:80
 > #10221 0x080484fe in main ()
 
 Hmmmm.
 
 The verbose terminate handler re-throws the exception in order to try and
 give the user more help:
 
         // If the exception is derived from std::exception, we can give more
         // information.
         try { __throw_exception_again; }
     #ifdef __EXCEPTIONS
         catch (exception &exc)
           {
             char const *w = exc.what();
             writestr("  what():  ");
             writestr(w);
             writestr("\n");
           }
     #endif
         catch (...) { }
 
 The rethrow never... eh, I don't know how to express this clearly.
 
 The rethrow never rethrows; it never leaves the try block.  Instead,
 the support routine __cxa_rethrow calles std::terminate, and there's the
 infinite loop.
 
 I have no idea why; the core dump I get (and the rest of us got during
 testing) shows this:
 
 #0  0x40124a51 in kill () from /lib/libc.so.6
 #1  0x40124872 in raise () from /lib/libc.so.6
 #2  0x40125986 in abort () from /lib/libc.so.6
 #3  0x400a1fcb in __gnu_cxx::__verbose_terminate_handler() () at /home/pme/src/unified/libstdc++-v3/libsupc++/vterminate.cc:96
 
 The same thing up until the rethrow; it's supposed to finish the rethrow,
 hit the "catch (...) { }" line, and then abort() a few lines later (line 96).
 
 
 Phil
 
 -- 
 I would therefore like to posit that computing's central challenge, viz. "How
 not to make a mess of it," has /not/ been met.
                                                  - Edsger Dijkstra, 1930-2002