[Dwarf-discuss] Using CFI to end a backtrace

[Daniel Jacobowitz]

Several times recently I have wanted a "clean" way to indicate to GDB
that a backtrace was over - give up, go away, nothing more to see here.
This is useful in startup code, kernel exception handlers, et cetera.
There's no immediately obvious way to use .debug_frame for this;
however, it seems to me that marking the return address column as
DW_CFA_undefined should do what I want.  If we can't find the return
address, then there's no point in unwinding further.

Does this interpretation make sense?  If so, should it be documented,
so that others don't need to reinvent it?

-- 
Daniel Jacobowitz
CodeSourcery, LLC