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Re: gdb requires watchpoints to fire after the write
> Pedro> Yeah, it's confusing.
>
> [... great explanation ... ]
>
> This would be great as comments in gdbarch.sh and target.h.
> None of these things have comments currently.
Agreed. I was going to send a patch doing so when I read Pedro's
message, and then read this. I'm happy to do the patch, but don't
want to start if Pedro is already on it.
> Pedro> We could most probably streamline all of this and come up with a better
> Pedro> design with some thought. See also the comment in mips-tdep.c:
>
> Pedro> /* FIXME: cagney/2003-08-29: The macros target_have_steppable_watchpoint,
> Pedro> HAVE_NONSTEPPABLE_WATCHPOINT, and target_have_continuable_watchpoint
> Pedro> need to all be folded into the target vector. Since they are
> Pedro> being used as guards for target_stopped_by_watchpoint, why not have
> Pedro> target_stopped_by_watchpoint return the type of watchpoint that the code
> Pedro> is sitting on? */
> Pedro> set_gdbarch_have_nonsteppable_watchpoint (gdbarch, 1);
>
> I'm curious about why this should be in the target rather than in the
> gdbarch. It seems like a property of the ISA.
>
> Is it possible for gdbserver to do the single-step itself, avoiding a
> round trip? That was the only rationale I could think of.
It might not be gdbserver itself, which I don't think should try
to remain as minimalistic as possible in terms of this kind of
"intelligence", but maybe some other stubs? For instance, a stub
might be designed to be usable against another kind of debugger
which might be expecting a certain type of behavior forcing
the stub to have to do the single-step itself. (?)
My perspective is that, if we don't have a concrete situation where
this functionality should be a property of the target, and we find
that it simplifies the code or avoids confusion to remove that target
property, then let's. The obvious question then becomes - what to do
with ia64-linux? Is this platform still in use and relevant enough
for us to invest energy into redesigning the watchpoint support on
this platform a bit?
--
Joel