[CRIS] Backtrace past clone

[Orjan Friberg <orjan.friberg@axis.com>]

I'm having trouble with backtrace not stopping at clone (in the child). 
  Normally I rely on the Dwarf-2 CFI, but clone doesn't have any, so 
this falls back on the manual unwinder.

I understand that using frame pointer register != 0 is dubious (since 
the code we may end up analyzing in the manual unwinder could be 
compiled without a frame pointer), although the glibc clone function for 
CRIS does set the frame pointer to 0.  Other than that, I can't see how 
to detect that the call stack ends for the child.

I see this has been discussed for MIPS in the thread starting at 
http://sources.redhat.com/ml/gdb-patches/2004-03/msg00128.html, which 
also references missing Dwarf-2 information.  Besides this, "grep clone" 
in src/gdb gave surprisingly few hits, as did searching for "clone 
backtrace" in the gdb-patches archive.  The lack of architecture 
-specific search results me wonder if this is something that should be 
handled by the Dwarf-2 unwinder (and that what needs to be fixed is the 
missing Dwarf-2 CFI for clone).

Any suggestions?

-- 
Orjan Friberg
Axis Communications