Re: [patch] gdbserver regcache fetch all regs

[Aleksandar Ristovski <aristovski at qnx dot com>]

Doug Evans wrote:
> On Tue, Jun 16, 2009 at 6:24 PM, Aleksandar Ristovski<aristovski@qnx.com> wrote:
> > Hello,
> >
> > I believe this is a bug in gdbserver/regcache.c
> >
> > Current code fetches regno 0 and marks regcache valid. I believe correct
> > should be: fetch all regs, and mark regache valid.
> > [...];
> > ChangeLog:
> >
> >
> > * regcache.c (get_regcache): Fetch all registers instead of
> > regno 0 only.
>
> Hi.  At first I thought "Yikes!". :-)
> But it turns out that all fetch_registers routines treat 0 and -1 equivalently.
> I wouldn't hold up this patch (it's fine with me fwiw), though I would
> change the ChangeLog entry to something like: "Use -1 instead of 0 to
> fetch all registers." since passing 0 does actually fetch all
> registers.

Very interesting. I see that now, but in target.h it says 
quite unambiguously:

  /* Fetch registers from the inferior process.

     If REGNO is -1, fetch all registers; otherwise, fetch 
at least REGNO.  */

  void (*fetch_registers) (int regno);


> It would be good to remove this oddity and stop the conflation of 0
> and -1, but I don't know what would break.
> We could run the testsuite and see what happens as a start.
> Does anyone know the history behind this?


Thanks,
--
Aleksandar Ristovski
QNX Software Systems