think-o: dwarf2 CFA != frame->frame (x86-64)

[Andrew Cagney]

> 
> It might just be misnamed.

No.  DW_OP_fbreg refers explicitly to DW_AT_frame_base.  CFA is a 
concept local to the CFI.  They would typically evaluate to the same 
value though.

> I've converted rs6000 to use the dwarf2 cfa info (It's a little hairier, 
> since on x86-64, you *always* have the info, it's part of the ABI), and it 
> works just fine, even on optimized code.  This is with the fallback to 
> normal methods in case the info isn't in the executable, disabled, so i'd 
> get errors if it wasn't using *only* the dwarf2 info.
> 
> 

See:

http://sources.redhat.com/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gdb&pr=466

Andrew