On Mon, Jun 23, 2014 at 2:04 PM, David Blaikie <[email protected]> wrote: > On Mon, Jun 23, 2014 at 2:02 PM, Eric Christopher <[email protected]> wrote: >>>> Hm, perhaps. I would be penalizing -Rpass, however. But I guess it doesn't >>>> matter much. I'll amend the documentation to state that -gcolumn-inf is >>>> needed with -Rpass. >>> >>> Well it's not worse - currently -Rpass doesn't enable debug info at >>> all , but I suppose it at least suggests the user enable both -gmlt >>> and -gcolumn-info. But I assume if they enabled -g(mlt or otherwise) >>> they wouldn't be told they should use -gcolumn-info. >>> >>> So, committing this patch without the column info would be sort of a >>> regression, but sort of not... Given this is a developer feature only, >>> I'm OK with it being a little rough around the edges. Up to you >>> though, we can discuss the issues with -gcolumn-info and -Rpass in >>> this review if you prefer. Just figured it'd be better to separate >>> them if practical. >>> >> >> Separately from the rest of the patch we might want to look into >> turning column info back on for -gmlt in particular. It's the use case >> for the sanitizers etc and so having slightly more accurate back >> traces is a fairly good thing there. Especially as we get the size of >> -gmlt down we can look into using that room for things that are >> explicitly useful. >> >> Thoughts? > > Sure, sounds plausible. I have this vague recollection that one of the > reasons it was turned off was performance implications in clang, > querying for the column info for everything wasn't terribly cheap - > but I'm probably misremembering. Maybe it's just creating the extra > MDNodes that gets costly. > > In any case, whatever the cost was, if any (maybe it was just "GDB > gets weird when you add column info" - in which case that's less of > (not at all?) a problem for -gmlt). >
IIRC it was mostly "it's a lot of size and nothing uses it". It was also non-trivial for compile time. -eric _______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
