Re: proposed PATCH: make watchpoints work correctly

[Daniel Jacobowitz <drow at mvista dot com>]

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