[PATCH] Re: Unwinding CFI gcc practice of assumed `same value' regs

[Mark Kettenis]

>  On Wed, Dec 13, 2006 at 09:46:04PM +0100, Jan Kratochvil wrote:
> > Attaching patch for current gdb CVS to properly terminate on return
> > address 0.
> > The check was already present there but it got applied one backward step
> > later.
> >
> > I hope these three patches are be 100% reliable and also backward
> > compatible.
>
>  Please read the previous discussion and patch on this topic:
>    http://sourceware.org/ml/gdb-patches/2006-07/msg00392.html
>
>  Mark, I don't suppose you find it convincing that the libgcc unwinder
>  terminates on PC == 0 too?

It's a perfectly reasonable thing for the libgcc unwinder to do (just
as it is for us in GDB).  But in a debugger I want to see that PC == 0
if it is an abnormal backtrace termination.

What really needs to be done is making the DWARF2 unwinder recognize the
condition and return a suitable frame id for that.

Mark