Re: proposed PATCH: make watchpoints work correctly

Paul Koning
2003-05-29T15:17:54Z

>>>>> "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.

paul