Re: trouble with gdb backtraces on ppc with gcc4

[Andreas Schwab <schwab@suse.de>]

Olaf Hering <olh@suse.de> writes:

> the backtraces in gdb 6.3 and also in gdb-mainline are usually broken in
> openSuSE. How does gdb generate them? I guess gdb needs to deal with the
> gcc generated debug info.

When there is one.  In your example there isn't.  The openSuSE gdb has
been patched to make use of the DWARF unwind information, which works
quite well if it is present.

> (gdb) bt
> #0  0x0ff6443c in __write_nocancel () from /lib/tls/libc.so.6
> #1  0x0ff141c4 in _IO_new_file_write () from /lib/tls/libc.so.6
> #2  0x0ff126e0 in new_do_write () from /lib/tls/libc.so.6
> #3  0x0ff12898 in _IO_new_do_write () from /lib/tls/libc.so.6
> #4  0x0ff13424 in _IO_new_file_overflow () from /lib/tls/libc.so.6
> #5  0x0ff143f4 in _IO_new_file_xsputn () from /lib/tls/libc.so.6
> #6  0x0feeb990 in vfprintf () from /lib/tls/libc.so.6
> #7  0x0feeb990 in vfprintf () from /lib/tls/libc.so.6

No debug info in /lib/tls/libc.so.6.  Will work fine when debug info
exists.

> SLES9 does a better job:

SLES9 has an older compiler, which does less aggressive optimisations.

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
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