RE: Question about solaris CANNOT_STEP_HW_WATCHPOINTS macro

["Pierre Muller" <pierre dot muller at ics-cnrs dot unistra dot fr>]

  I reproduced Pieter's results and filed
a bug report:
http://sourceware.org/bugzilla/show_bug.cgi?id=11531

  This changes the scenery completely:
it becomes important that CANNOT_STEP_HW_WATCHPOINTS macro
does not get set.
  If, as Pedro said, GDB does not check for a hardware watchpoint 
trigger after the step anyway, the whole code of this macro
becomes useless and only creates problems.

  I will try to submit a testcase for this bug report.

Pierre Muller

> -----Message d'origine-----
> De?: gdb-owner@sourceware.org [mailto:gdb-owner@sourceware.org] De la
> part de Pieter Maljaars
> Envoyé?: Friday, April 23, 2010 9:42 AM
> À?: Joel Brobecker; Pierre Muller
> Cc?: Peter.Schauer@regent.e-technik.tu-muenchen.de; gdb@sourceware.org;
> 'Joseph S. Myers'; 'Pedro Alves'
> Objet?: Re: Question about solaris CANNOT_STEP_HW_WATCHPOINTS macro
> 
> > Looks like a different bug is now occurring:
> >
> >     (gdb) start
> >     Temporary breakpoint 1 at 0x805067a: file foo.c, line 13.
> >     Starting program: [...]/foo
> >
> >     Temporary breakpoint 1, main () at foo.c:13
> >     13        myrec.x = 5;
> >     (gdb) print myrec.x
> >     $1 = 0
> >     (gdb) watch myrec.x
> >     Hardware watchpoint 2: myrec.x
> >     (gdb) s
> >     14        myrec.y = 3.4;
> 
> I have tested this with Solaris 2.10 and GDB-7.1. I have removed
> the CANNOT_STEP_HW_WATCHPOINT define.  Here this bug does not occur.
> 
>     (gdb) start
>     Temporary breakpoint 1 at 0x8050681: file watchp.c, line 13.
>     Starting program: [...]/watchp
> 
>     Temporary breakpoint 1, main () at watchp.c:13
>     13        myrec.x = 5;
>     (gdb) print myrec.x
>     $1 = 0
>     (gdb) watch myrec.x
>     Hardware watchpoint 2: myrec.x
>     (gdb) s
>     Hardware watchpoint 2: myrec.x
> 
>     Old value = 0
>     New value = 5
>     main () at watchp.c:14
>     14        myrec.y = 3.4;
> 
> 
> Here it works as expected.  GDB stops also at the other watchpoint.
> So with "step" and "continue" both watchpoints are triggered, like
> it behaves on x86-linux.
> 
> Pieter Maljaars