PATCH: gdbserver: Clear regcache if buf is NULL
Mark Kettenis
mark.kettenis@xs4all.nl
Sun Oct 31 13:25:00 GMT 2010
> From: Pedro Alves <pedro@codesourcery.com>
> Date: Sat, 16 Oct 2010 21:49:36 +0100
>
> On Saturday 16 October 2010 21:16:37, H.J. Lu wrote:
> > >
> > > Thanks, and sorry as for not coming back to this promptly.
> > > Hmm, I don't think I have a way to trigger that.
> > > So is the registers' value really zero, or should gdb
> > > ideally present them as not available (and zero is just a
> > > hack)?
> > >
> >
> > You will see it only on machines with XSAVE and enabled in OS.
> > Please see
> >
> > 13.6 XSAVE/XRSTOR AND PROCESSOR EXTENDED STATE
> > MANAGEMENT
> >
> > in
> >
> > Intel® 64 and IA-32 Architectures Software DeveloperÂs Manual
> > Volume 3A: System Programming Guide, Part 1
> >
> > Basically values in vector registers may not be valid, depending
> > on vector state.
>
> Okay, thanks. The changes I'm working on would make gdb print
> for such registers:
>
> (gdb) info registers
> ...
> foo-register *value not available*
> ...
>
> rather than:
>
> (gdb) info registers
> ...
> foo-register 0x0 0
> ...
>
> Trying to print the register's value will show something
> like "$1 = <unavailable>", and using it's value in expression
> evaluation to determine a computed expression value, an error
> will be reported.
>
> Does that sound good? Or do you think keep using 0 would
> be better in this case?
I think that sounds good.
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