Re: [patch, rfc, 6.0] Change frame predicates to sniffers

[Andrew Cagney <ac131313@redhat.com>]

> Hello,
> 
> This patch adds frame sniffers (name stolen from other sniffer code) to the frame code.  Unlike the existing frame predicate methods that take a PC parameter, these take a full NEXT_FRAME.  It leaves the old frame predicates alone (making this safe for the branch).
> 
> I figure that should be enough to keep any unwinder, trying to decide if the frame is good, happy :-)
> 
> I'll look to commit this to both the trunk and 6.0 branch early next week.  I'll then follow up with patches to:
> 
> - rips out the old predicate methods (mainline only)
> 
> - replace the dwarf2 predicate with a dwarf2 sniffer
> Will apply to mainline and branch.  Should fix weird edge case where a function has no cfi but is doing a tail call to a no-return function, but the code following the function does have CFI.
> 
> - (I guess) something to work around the dwarf2 unwind info (need to look at Mark's old code)
> 
> I've so far tested it on a RH9 system (with the sniffer enabled) and it hasn't shown a sign of regressing.
> 
> Can anyone point me at testcases that will magically start passing with this fixed?

I've checked this part in

Andres ;-)