RE: [RFA] Patch to fix "reverse-next" command error

Marc Khouzam
2009-06-15T15:37:05Z

> -----Original Message-----
> From: gdb-patches-owner@sourceware.org
> [mailto:gdb-patches-owner@sourceware.org] On Behalf Of Hui Zhu
> Sent: June-15-09 2:47 AM
> To: Michael Snyder; Marc Khouzam
> Cc: gdb-patches@sourceware.org
> Subject: Re: [RFA] Patch to fix "reverse-next" command error
>
> On Mon, Jun 15, 2009 at 10:45, Michael
> Snyder<msnyder@vmware.com> wrote:
> > Hui Zhu wrote:
> >>
> >> Ping.
> >
> > Hui, I rewrote your patch a little bit.  I think we can use
> > gdbarch_skip_trampoline_code to detect the fact that we have
> > stepped into a trampoline (ie. "plt").  This is more general.
> >
> > Mark, please tell me if this patch fixes your original problem,
> > and Hui, please tell me if the patch is OK with you.
> >
>
> This patch is OK with me.

I also tested this one and it works great for me as well.

Thanks

>
> BTW, the patch that you sent include the prev one.
>
>
> Thanks,
> Hui
>
> >> On Mon, May 11, 2009 at 15:07, Hui Zhu<teawater@gmail.com> wrote:
> >>>
> >>> PING
> >>>
> >>> On Wed, May 6, 2009 at 14:00, Hui Zhu <teawater@gmail.com> wrote:
> >>>>
> >>>> Hi Michael,
> >>>>
> >>>> I try this issue with cvs-head.  It still affect cvs-head.
> >>>> And I try the patch, it can fix this issue.  It's time
> close to 7.0
> >>>> branch.  So could you please help me review it?
> >>>>
> >>>> The attachment is the new patch follow cvs-head.
> >>>>
> >>>> 2009-05-06  Hui Zhu  <teawater@gmail.com>
> >>>>
> >>>>      * infrun.c (handle_inferior_event): Make inferior step if it
> >>>>      stepping over a function call in reverse , and stop at the
> >>>>      start address of the function.
> >>>>
> >>>> Thanks,
> >>>> Hui
> >>>>
> >>>> On Thu, Jan 22, 2009 at 17:00, teawater
> <teawater@gmail.com> wrote:
> >>>>>
> >>>>> Hi guys,
> >>>>>
> >>>>> This patch is for bug in
> >>>>> http://sourceware.org/ml/gdb/2009-01/msg00146.html
> >>>>>
> >>>>> This issue is because sometime the inferior is already
> in function
> >>>>> start address (i.e. plt), set a breakpoint and continue
> will make
> >>>>> "reverse-next" work error.
> >>>>>
> >>>>> This patch make inferior step if it reverse step and stop at the
> >>>>> function start address.
> >>>>> It tested OK with process record patch and testsuite
> gdb.twreverse in
> >>>>> branch reverse-20081226-branch.
> >>>>>
> >>>>> 2009-01-22  Hui Zhu  <teawater@gmail.com>
> >>>>>
> >>>>>       * infrun.c (handle_inferior_event): Make inferior
> step if it
> >>>>>       stepping over a function call in reverse , and stop at the
> >>>>>       start address of the function.
> >>>>>
> >>>>> OK for mainline?
> >>>>>
> >>>>> Thanks,
> >>>>> Hui
> >>>>>
> >>
> >
> >
> > 2009-06-14  Hui Zhu  <teawater@gmail.com>
> >            Michael Snyder  <msnyder@vmware.com>
> >
> >        * infrun.c (handle_inferior_event): Reverse-next
> through trampoline.
> >
> > Index: infrun.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/infrun.c,v
> > retrieving revision 1.387
> > diff -u -p -r1.387 infrun.c
> > --- infrun.c    11 Jun 2009 11:57:46 -0000      1.387
> > +++ infrun.c    15 Jun 2009 02:39:51 -0000
> > @@ -3623,9 +3623,17 @@ infrun: not switching back to stepped th
> >
> >      Note that step_range_end is the address of the first
> instruction
> >      beyond the step range, and NOT the address of the last
> instruction
> > -     within it! */
> > +     within it!
> > +
> > +     Note also that during reverse execution, we may be stepping
> > +     through a function epilogue and therefore must detect when
> > +     the current-frame changes in the middle of a line.  */
> > +
> >   if (stop_pc >= ecs->event_thread->step_range_start
> > -      && stop_pc < ecs->event_thread->step_range_end)
> > +      && stop_pc < ecs->event_thread->step_range_end
> > +      && (execution_direction != EXEC_REVERSE
> > +         || frame_id_eq (get_frame_id (get_current_frame ()),
> > +                         ecs->event_thread->step_frame_id)))
> >     {
> >       if (debug_infrun)
> >        fprintf_unfiltered (gdb_stdlog, "infrun: stepping
> inside range
> > [0x%s-0x%s]\n",
> > @@ -3762,10 +3770,21 @@ infrun: not switching back to stepped th
> >                  keep_going (ecs);
> >                  return;
> >                }
> > -             /* Normal (staticly linked) function call return.  */
> > -             init_sal (&sr_sal);
> > -             sr_sal.pc = ecs->stop_func_start;
> > -             insert_step_resume_breakpoint_at_sal (sr_sal,
> null_frame_id);
> > +             if (gdbarch_skip_trampoline_code(current_gdbarch,
> > +                                              get_current_frame (),
> > +                                              stop_pc))
> > +               {
> > +                 /* We are in a function call trampoline.
> > +                    Keep stepping backward to get to the
> caller.  */
> > +                 ecs->event_thread->stepping_over_breakpoint = 1;
> > +               }
> > +             else
> > +               {
> > +                 /* Normal function call return (static or
> dynamic).  */
> > +                 init_sal (&sr_sal);
> > +                 sr_sal.pc = ecs->stop_func_start;
> > +                 insert_step_resume_breakpoint_at_sal (sr_sal,
> > null_frame_id);
> > +               }
> >            }
> >          else
> >            insert_step_resume_breakpoint_at_caller
> (get_current_frame ());
> >
> >
>