Re: proposed PATCH: make watchpoints work correctly

Daniel Jacobowitz
2003-05-29T15:37:20Z

On Thu, May 29, 2003 at 11:17:54AM -0400, Paul Koning wrote:
> >>>>> "Eli" == Eli Zaretskii <eliz@elta.co.il> writes:
>
> >> Date: Wed, 28 May 2003 16:27:33 -0400 From: Paul Koning
> >> <pkoning@equallogic.com>
> >>
> Eli> The above description made me nervous: it almost sounds like the
> Eli> current watchpoint support is pretty much dysfunctional, as most
> Eli> of the changes you suggest are not specific neither to remote.c
> Eli> nor to HAVE_NONSTEPPABLE_WATCHPOINT. So could you please
> Eli> explain how, given those deficiencies, watchpoints do work for
> Eli> native targets such as x86, but did not work for your target?
> >> I'm not sure. I just built a gdb for x86 on NetBSD, and all I get
> >> is software write watchpoints, no hardware watch support seems to
> >> be present.
>
> Eli> That's strange: I thought hardware-assisted watchpoints were
> Eli> supported for all native x86 platforms. Mark, could you please
> Eli> help us out here? is NetBSD an exception?
>
> I built 5.3 for Linux and did the experiment there. Hardware
> watchpoints do work there.
>
> Eli> I don't have time right now to read the parts of breakpoint.c
> Eli> that you describe, but I promise to do that later today. Thanks
> Eli> for taking time to explain your reasoning.
>
> >> The purpose of this patch submission is to get input from experts
> >> -- not necessarily to claim that the fix I submitted is the best
> >> way to solve the problem...
>
> Eli> Certainly, I understand that. I just was surprised that your
> Eli> description of the problem was so different from my recollection
> Eli> of how watchpoints work.
>
> I just ran a small test case on the x86 Linux native build of gdb 5.3,
> and the problem (step works as if it were stepi, falsely reported as a
> watchpoint hit) occurs there as well -- just as expected.

I don't know how facile you are with expect, but could you either write
a full testcase or at least give me a small sample code and session
transcript to reduce the problem, so that this can go into the
testsuite?

--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer