How does gdb deal with bizarre frame descriptions?

[Tom Horsley]

On Wed, 19 May 2010 18:41:59 -0400
Mike Frysinger wrote:

> look at the frames sections of the gdb internals manual as it describes the 
> algorithms gdb uses (or rather, the framework gdb has that each arch/port 
> extends).
> 
> you can also use 'set debug frame 1' to get more insight on the frame 
> construction.

Thanks for the pointers, but I think I have discovered that the
compiler is actually generating correct, but ridiculous frame info.
The code really is using ebp as a frame register, but it also
has stored a copy of the frame pointer on the stack and described
that saved copy in the dwarf instead of just using ebp+offset
like all the code it generated actually does. I have no clue
why it does that :-).