RE: Reverse debugging

Marc Khouzam
2009-09-11T13:26:23Z

Hi,

the time for 7.0 is fast approaching and I was hoping
to have a solution for setting memory during reverse debugging.
If you remember, when using Eclipse, the use of nquery() automatically
makes the answer be 'N', so I can never set memory during reverse.

We didn't reach a consensus on genericallyfixing queries for frontends and
I believe the most popular solution was to add a switch to enable/disable
this specifc query.

Hui, shall I write a patch for this?
For simplicity, I would go for
set record query <on | off>
which would enable/disable all precord queries.

Sound good?

Thanks

Marc

> -----Original Message-----
> From: Hui Zhu [mailto:teawater@gmail.com]
> Sent: Sunday, July 19, 2009 11:27 PM
> To: Marc Khouzam; Nick Roberts
> Cc: Daniel Jacobowitz; gdb@sources.redhat.com; Michael Snyder
> Subject: Re: Reverse debugging
>
> Thanks Marc, but what about I keep it but add some switches for it?
> I want keep the query to tui user.
> For example:
> set record query off
> set record changememeory on
>
> Thanks,
> Hui
>
>
> On Sun, Jul 19, 2009 at 11:19, Marc
> Khouzam<marc.khouzam@ericsson.com> wrote:
> >> -----Original Message-----
> >> From: Daniel Jacobowitz [mailto:drow@false.org]
> >> Sent: July-17-09 10:25 AM
> >> To: Marc Khouzam
> >> Cc: Nick Roberts; Hui Zhu; gdb@sources.redhat.com; Michael Snyder
> >> Subject: Re: Reverse debugging
> >>
> >> On Fri, Jul 17, 2009 at 10:12:00AM -0400, Marc Khouzam wrote:
> >> > I noticed that the previous CDT GDB integration has its console
> >> > considered
> >> > a tty.  It may be worth looking into the difference... when
> >> time allows
> >> > it :-)
> >>
> >> Wasn't someone just talking on cdt-dev about trouble with
> whether DSF
> >> used Spawner or not?  That'd do it.
> >
> > I was wrong about the console being a tty.  The old CDT GDB
> integration
> > console is also not a tty.  What they do though is use
> > 'set confirm off'.  That makes sense since queries are
> being answered
> > automatically anyway.
> >
> > Nick, in your specific case 'confirm off' would work.  The default
> > answer to
> > 'record stop' is yes (well, there is not default, but in
> that case, 'y'
> > is
> > chosen).  If you don't want to always 'set confirm off' you
> may consider
> > setting it right before sending 'record stop' and turn it back on
> > right after.  That may be a good enough workaround until there is a
> > proper
> > solution to this query problem.
> >
> > For me the problem for PRecord remains because the default value is
> > not always what I want.  For example, in PRecord the default answer
> > to changing memory and loosing the recorded history
> > is "N", but as a frontend, I want to answer "Y".
> >
> > To fix this problem I suggest that in record.c,
> > we replace 'nquery' with 'query'; that will make the
> default be 'Y' when
> >
> > confirm is off or when there is no tty.  Note that this
> seems to be what
> >
> > is being done everywhere else in GDB.  There is only one
> case (pending
> > breakpoints) that uses default queries, outside of PRecord.
>  Except for
> > that
> > one case, it is really only PRecord that uses yquery and
> nquery.  And
> > the
> > pending breakpoint case is not a problem for frontends that use MI
> > because
> > the MI command does not trigger the query.
> >
> > Note that up to now, I've been recompiling GDB with that suggestion
> > so that I can properly use PRecord in Eclipse.
> >
> > The below patch implements the suggestion.
> >
> > Thanks
> >
> > Marc
> >
> > ChangeLog
> > 2009-07-18  Marc Khouzam  <marc.khouzam@ericsson.com>
> >
> >        * record.c (record_store_registers): Replace nquery with
> >        query to allow frontends to automatically answer 'y'.
> >        (record_xfer_partial): Ditto.
> >
> >
> > ### Eclipse Workspace Patch 1.0
> > #P src
> > Index: gdb/record.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/record.c,v
> > retrieving revision 1.8
> > diff -u -r1.8 record.c
> > --- gdb/record.c        2 Jul 2009 17:21:06 -0000       1.8
> > +++ gdb/record.c        19 Jul 2009 03:06:01 -0000
> > @@ -937,13 +937,13 @@
> >          /* Let user choose if he wants to write register
> or not.  */
> >          if (regno < 0)
> >            n =
> > -             nquery (_("Because GDB is in replay mode,
> changing the "
> > +             query (_("Because GDB is in replay mode,
> changing the "
> >                        "value of a register will make the
> execution "
> >                        "log unusable from this point onward.  "
> >                        "Change all registers?"));
> >          else
> >            n =
> > -             nquery (_("Because GDB is in replay mode, changing the
> > value "
> > +             query (_("Because GDB is in replay mode, changing the
> > value "
> >                        "of a register will make the execution log
> > unusable "
> >                        "from this point onward.  Change
> register %s?"),
> >                      gdbarch_register_name (get_regcache_arch
> > (regcache),
> > @@ -993,7 +993,7 @@
> >       if (RECORD_IS_REPLAY)
> >        {
> >          /* Let user choose if he wants to write memory or not.  */
> > -         if (!nquery (_("Because GDB is in replay mode, writing to
> > memory "
> > +         if (!query (_("Because GDB is in replay mode, writing to
> > memory "
> >                         "will make the execution log
> unusable from this
> > "
> >                         "point onward.  Write memory at
> address %s?"),
> >                       paddress (target_gdbarch, offset)))
> >
> >
> >
> >
>