STOPPED_BY_WATCHPOINT peculiarity

[Daniel Jacobowitz]

On Tue, Apr 02, 2002 at 01:54:47PM -0800, Doug Evans wrote:
> Something is not right, or at least confusing, in watchpoint-land.
> 
> This code in infrun.c is odd:
> 
>     /* It may be possible to simply continue after a watchpoint.  */
>     if (HAVE_CONTINUABLE_WATCHPOINT)
>       STOPPED_BY_WATCHPOINT (ecs->ws);
> 
> STOPPED_BY_WATCHPOINT is a predicate.
> Therefore at first glance this code is pointless.
> 
> Things are slightly less confusing by recognizing that in the
> process of computing STOPPED_BY_WATCHPOINT some debugging printf's
> may get printed.  e.g. grep for maint_show_dr in
> i386-nat.c:i386_stopped_data_address.
> 
> nm-i386.h:
> #define STOPPED_BY_WATCHPOINT(W)       (i386_stopped_data_address () != 0)
> 
> Is that all there is to it?
> 
> If so, a comment should be added, maybe something like
> 
> -    /* It may be possible to simply continue after a watchpoint.  */
> +    /* It may be possible to simply continue after a watchpoint.
> +       While at first glance this code is pointless, STOPPED_BY_WATCHPOINT
> +       is called in case there are any maintenance debugging printf's.  */
>      if (HAVE_CONTINUABLE_WATCHPOINT)
>        STOPPED_BY_WATCHPOINT (ecs->ws);

What astonishing timing... I believe there is more going on here, and I
was in the middle of looking at this code just a moment ago.  See the
test failure on i386-linux in gdb.c++/annota2.exp (watch a.x).  We have
a problem actually correctly detecting that we are stopped by a
watchpoint.

-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer