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

[Daniel Jacobowitz]

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?

-- 
Daniel Jacobowitz
CodeSourcery