On Tue, 2012-11-27 at 19:49 +0100, Ulrich Weigand wrote: > Mark Wielaard wrote: > > > Which other unwinders are out there, that might rely on the current > > numbering? > > Well, runtime unwinders using .eh_frame should be fine, since this > uses (and has always used) consistently the GCC numbering. I don't > know if there are other unwinders using .dwarf_frame ...
The reason systemtap hits this is that it can do unwinding of both user and kernel space. The linux kernel doesn't include eh_frames, so we have to fall back to .debug_frame. > The change will most likely be to consistently use GCC numbering in > .dwarf_frame as well, which changes only the encoding of the condition > code register. Since you're not using that at all in systemtap, you > shouldn't be affected. Yeah, we only use the unwinder currently to produce backtraces, which are unlikely to rely on the condition code register. > As far as Linux goes, yes, ppc was the only architecture with a > different encoding between .eh_frame and .dwarf_frame. In that case your option 3 seems ideal. Thanks, Mark
