SUMMARY: gdb: incomplete backtrace, strange step(?) in C++ (egcs 1.1.2)

From: Achim Bohnet <ach_at_mpe.mpg.de>
Date: Wed, 26 Jul 2000 21:43:16 +0200

Hallo,

busy day so the summary was delayed half a day. Sorry.


Thanks to

  Richard L Jackson Jr <rjackson_at_gmu.edu>
  Tim Mooney <mooney_at_dogbert.cc.ndsu.nodak.edu>

Summary:

  next/step:
        It's a bug in gcc (and egcs) that should be fixed in cvs and
        therefore in the next gcc release. Workaround are also available:
        Here's are gcc patches

                http://gcc.gnu.org/ml/gcc-patches/2000-05/msg01285.html
                http://gcc.gnu.org/ml/gcc-patches/2000-05/msg01282.html

        or gdb patches:

                http://sources.redhat.com/ml/bug-gdb/1999-04/msg00109.html

        Someone else mentioned that -gcoff instead of -g also helps

                http://sources.redhat.com/ml/bug-gdb/2000-04/msg00038.html

  incomplete backtrace
        Looks like this need more investigations and is not fixed up to
        now.

I still have to try the solutions but I better wait until the workload
is below 10 again. I will summarize again when I've verified that one
or more of them work here too.

Achim
P.S. Here's my original question:

Achim Bohnet writes:
>
> Hello,
>
> we use(d) gdb 4.17,4,18 and 5.0 together with egcs 1.1.2 on
> V4.0E + duv40eas0004 jumbo patch. Debugging C++ code for, e.g, SEGV
> or FPE shows incomplete backtraces. Most of the
> time 'bt' lists a Constructor and the methods called from there.
> But all frames that called the constructor are lost.
>
> A brute force interative N*next+crash then (N-1)next+step etc
> does not work because because 'step' instead of 'next' also crashes with
> and empty backtrace and gdb tells me that the 'current line' is
> the opening brace of a metthod.
>
> Therefore it's almost impossible to debug :(
>
> Egcs and gdb are build straight forward: configure, make .. etc. Only
> egcs uses -fsquangle as default (in gcc/cp/decl2.c from GCC FAQ).
>
> Has anybody a reliably combination of gdb/g++ on Digital Unix?
>
> Will summarize.
>
> Thx,
> Achim

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Received on Wed Jul 26 2000 - 19:44:39 NZST