RE: Wrong Reverse result

["Marc Khouzam" <marc.khouzam@ericsson.com>]

> -----Original Message-----
> From: Hui Zhu [mailto:teawater@gmail.com] 
> Sent: June-11-09 1:34 AM
> To: Marc Khouzam
> Cc: gdb@sourceware.org; Michael Snyder
> Subject: Re: Wrong Reverse result
> 
> I have reproduced this issue and find out the cause.

Great.  Thanks for doing that so quick.
I forgot how to turn on those nice traces.  Can you 
remind me?
The traces don't mean much to me, but I can include them
in any future (if any :-)) issues.

> infrun: TARGET_WAITKIND_STOPPED
> infrun: stop_pc = 0x8048361
> infrun: stepped into subroutine
> infrun: inserting step-resume breakpoint at 0x8048349
> 
> stop_stepping is better.
> 
> infrun: resume (step=0, signal=0), trap_expected=0
> infrun: prepare_to_wait
> infrun: target_wait (-1, status) =
> infrun:   10798 [process 10798],
> infrun:   status->kind = no-history
> infrun: infwait_normal_state
> 
> No more reverse-execution history.
> infrun: stop_stepping
> main () at 1.c:7
> 
> On Thu, Jun 11, 2009 at 00:49, Marc 
> Khouzam<marc.khouzam@ericsson.com> wrote:
> > Hi,
> >
> > I'm getting a weird behaviour in reverse, where GDB
> > jumps to far backwards.
> >
> > I have GDB HEAD from two weeks ago with the three
> > missing PRrecord patches applied (that were pinged
> > by Hui this very week).
> 
> All of patches are not for prec, they are for reverse.

I realized that just after pressing 'send' :-)

> > I'm running on Ubuntu.
> > Is it me or can someone reproduce it?
> > (It happened during my presentation at the GCC summit,
> > so I have witnesses :-))
> 
> I am not sure Michael in GCC summit or not.  If so, you can let he fix
> it at there directly.  :)

The summit is over now, but I did meet with Michael.  It's nice to see
people face to face.  I was able to put a bit of pressure on him
about reviewing the missing patches ;-).  I'm sure that as soon as he
has time, he'll have a look at these four things.

Thanks Hui

marc

> 
> Thanks for your help.
> 
> Hui
> 
> >
> > Thanks
> >
> > Marc
> >
> > GNU gdb (GDB) 6.8.50.20090522-cvs
> > Copyright (C) 2009 Free Software Foundation, Inc.
> > License GPLv3+: GNU GPL version 3 or later
> > <http://gnu.org/licenses/gpl.html>
> > This is free software: you are free to change and redistribute it.
> > There is NO WARRANTY, to the extent permitted by law.  Type "show
> > copying"
> > and "show warranty" for details.
> > This GDB was configured as "i686-pc-linux-gnu".
> > For bug reporting instructions, please see:
> > <http://www.gnu.org/software/gdb/bugs/>...
> > (gdb) l
> > 1       void foo() {
> > 2           return;
> > 3       }
> > 4
> > 5       int main() {
> > 6
> > 7               foo(); // 1
> > 8               foo(); // 2
> > 9               foo(); // 3
> > 10
> > (gdb) l
> > 11              return 0;
> > 12      }
> > (gdb) start
> > Temporary breakpoint 1 at 0x80483f7: file r.c, line 7.
> > Starting program: /home/marc/testing/a.out
> >
> > Temporary breakpoint 1, main () at r.c:7
> > 7               foo(); // 1
> > Current language:  auto; currently c++
> > (gdb) record
> > (gdb) n
> > 8               foo(); // 2
> > (gdb) n
> > 9               foo(); // 3
> > (gdb) n
> > 11              return 0;
> > (gdb) rn
> > 9               foo(); // 3
> > (gdb) s
> > foo () at r.c:3
> > 3       }
> > (gdb) rn
> >
> > No more reverse-execution history.
> > main () at r.c:7
> > 7               foo(); // 1
> >
> > ======== This is weird.  Why does it go back to the top?
> >
>