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

["Mark Kettenis" <mark.kettenis@xs4all.nl>]

>  On Wed, Dec 13, 2006 at 10:40:52PM +0100, Mark Kettenis wrote:
> > 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.
>
>  Sorry, but I'm confused again :-(
>
>  Do you mean making the DWARF2 unwinder decide that ra == 0 is a clean
>  terminator?  That seems like a bad thing to do if you want to ever show
>  PC == 0 as abnormal termination; then it will do so only if the last
>  frame left on the stack didn't have DWARF2 info.  Or do you mean some
>  other change to the unwinder?

No, sorry, it is me who is confused.  I didn't actually look at Jan's patch
and assumed it did the the right thing of marking the return address as
undefined.

Mark