Re: [RFA/PATCH] breakpoint.c: fix until command

[Michael Snyder <msnyder at redhat dot com>]

Elena Zannoni wrote:
> 
> Michael Snyder writes:
>  > Daniel Jacobowitz wrote:
>  > >
>  > > On Mon, Dec 23, 2002 at 04:57:00PM -0800, Michael Snyder wrote:
>  > > > Daniel Jacobowitz wrote:
>  > > > >
>  > > > > On Mon, Dec 23, 2002 at 03:53:22PM -0800, Michael Snyder wrote:
>  > > > > > Elena Zannoni wrote:
>  > > > > > >
>  > > > > > > This fixes the problem reported in:
>  > > > > > > http://sources.redhat.com/ml/gdb/2002-11/msg00144.html
>  > > > > > >
>  > > > > > > testsuite patch coming
>  > > > > >
>  > > > > > Elena, can you sum up in a sentence or two, what this change
>  > > > > > is intended to do?
>  > > > >
>  > > > > [Since I happen to be reading email right now, I'll do a sketchy
>  > > > > imitation.]
>  > > > >
>  > > > > The problem is that we were marking the breakpoint on the
>  > > > > user-specified line with the current frame.  But when we hit that
>  > > > > breakpoint, if it's in a different function, it will have a different
>  > > > > frame.  Right now we see that the frames don't match and resume
>  > > > > executing.
>  > > > >
>  > > > > Oops.
>  > > >
>  > > > OK, thanks.  But we _need_ to mark the breakpoint with the current
>  > > > frame, because if the breakpoint is in the current frame, we don't
>  > > > want to stop in an inner recursive call, ie. not until the current
>  > > > frame hits the breakpoint.
>  > > >
>  > > > So this needs further consideration, and I don't think it can
>  > > > be approved as is.
>  > >
>  > > OK.  Is that really what you expect "until" to do, though?  I'd be
>  > > pretty surprised if an inner function call executed that line without
>  > > stopping.
>  >
>  > Nevertheless, that is and has always been the intent.
>  > If you're in factorial(5), and you say "until 100",
>  > you don't stop until line 100 is hit by factorial(5).
> 
> I am tracking down this to something that changed between (ahem...)
> 4.18 and 5.0. The code in breakpoint.c didn't change. Right now,
> stepping the two gdb's side to side, I can see a difference in
> get_prev_frame, because of a different value returned by
> FRAME_CHAIN_VALID. :-( (i have not still stepped past that to see how
> that could influence the until foo behavior, maybe it doesn't).
> 
> The behavior you specify above is in 5.0 and not in 4.18, while the
> 'until foo' works in 4.18 and is broken in 5.0.
> 
> More digging.

Heh.  Clearly we need more "until" tests.   ;-/