RFC: implement DW_OP_call_frame_cfa
Tom Tromey
tromey@redhat.com
Tue Jun 9 15:51:00 GMT 2009
>>>>> "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
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