Re: RFC: implement DW_OP_call_frame_cfa

[Tom Tromey <tromey at redhat dot com>]

>>>>> "Daniel" == Daniel Jacobowitz <drow@false.org> writes:

Daniel> It isn't, sorry.  It will crash with bad debug info (e.g. manually
Daniel> stripped .debug_frame), because it runs the unwinder without passing
Daniel> through the sniffer.  It also allocates an entire unwinding cache for
Daniel> every local variable using this operation, which is very wasteful.

Thanks for the reply.

Daniel> I think, as much as we've tried to avoid it, you're going to need a
Daniel> back channel to find the existing cache iff the frame has a particular
Daniel> unwinder type.

Ok, I will look into this.

I could actually use a way to get the Dwarf CFA from a frame in the
next-over-throw case.  My current patch there does its CFA comparisons
in a bogus way (since I didn't really understand enough when I wrote
it...).

Daniel> IMO, not good enough; this is what gdb.dwarf2/ is for.  My compiler
Daniel> doesn't generate this extension but I'd still like to not break it.
Daniel> Maybe an x86-specific test?

Will do.

Tom