On Mon, Dec 10, 2012 at 10:07 PM, Mike Stump <mikest...@comcast.net> wrote: > On Dec 10, 2012, at 12:42 PM, Xinliang David Li <davi...@google.com> wrote: >> I have not measured the CFI size impact -- but conceivably it should >> be larger -- which is unfortunate. > > Code speed and size are preferable to optimizing dwarf size… :-) I'd let > dwarf 5 fix it!
Well, different to debug info, CFI data has to be in memory to make unwinding work. These days most Linux distributions enable asyncronous unwind tables so any size savings due to shorter push/pop epilogue/prologue sequences has to be offsetted by the increase in CFI data. I'm not sure there is really a speed difference between both variants (well, maybe due to better icache footprint of the push/pop variant). That said - I'd prefer to have more data on this before making the switch for the generic model. What was your original motivation? Just "theory" or was it a real case? Thanks, Richard.
