Re: backtrace issues

[Andrew Cagney <cagney@gnu.org>]

> At the time when we discussed this, we argued that the only hope was
> with dwarf2 CFI, but it just so happens that I noticed the exact same
> sort of problem on Windows XP (where we don't have dwarf-2 :-/).
> 
> I have been brooding for a while over this, and really don't see any
> solution to this, right now. Maybe it's unfair to say this: I find
> the new frame code well structured and blissfully free of all the hacks
> we used to have. However, it seems less tolerant to difficult cases,
> where we just stop unwinding while we used to be able to have a useful
> backtrace with 5.3.
> 
> (please don't see this as a complaint or don't think I am pointing
> finger at anybody - if I had found a better solution, believe me, 
> I would have sent a suggestion).

Have a look at the output from "set debug frame 1" (yes it is extreemly 
verbose but all the info is in there).  Two things could be going wrong 
(only two?):

- the debug info for the frame is wrong (gdb looses)
If you comment out the code adding the dwarf2 sniffer does it work 
better?  Things to do one day include "set backtrace unwind dwarf2 
{on,off}".  That it happens with XP indicates it is actually ...

- we lost something in translation
It's already using the traditional unwinder but the conversion frayed an 
edge case - straight debugging.

Andrew