[Dwarf-discuss] Using CFI to end a backtrace

[Andrew Cagney]

Check the archives, I proposed something similar some time ago.  Both 
the return address, and the CFA column are candidates.

Daniel Jacobowitz wrote:
> 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?