[PATCH] Add new debug kind LocTrackingOnly.

[Alexey Samsonov]

On Mon, Jun 23, 2014 at 3:20 PM, David Blaikie <dblaikie at gmail.com> wrote:

> On Mon, Jun 23, 2014 at 2:57 PM, Diego Novillo <dnovillo at google.com>
> wrote:
> >
> >
> >
> > On Mon, Jun 23, 2014 at 4:45 PM, David Blaikie <dblaikie at gmail.com>
> wrote:
> >>
> >>
> >> 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.
> >
> >
> > OK, I've removed the column info setting and modified the documentation
> to
> > match the current semantics.
> >
> > Let's try to enable column info with -gmlt separately, then. Should I
> open a
> > bug about it? Or do you prefer to handle it directly?
>
> I'm not sure it's something I'm strongly invested in either way -
> maybe Alexey (cc'd) has some idea of whether column info would add
> anything of significance to backtraces. I would guess currently the
> llvm symbolizer doesn't even try to handle column info, so it probably
> doesn't add any value to the backtraces at the moment? Would it be
> useful/appropriate, Alexey?
>

llvm-symbolizer correctly handles column info if it is present in the line
table.
However, I don't think column is that critical for the stacktraces, and
it's fine to
drop it, especially in -gmlt mode, where we care about minimizing debug
info size.
I vaguely remember that -gcolumn-info was introduced because column
information
significantly increased debug info size. I didn't make measurements myself,
though.



> Even then, don't mind having a discussion about column info for -Rpass
> stuff separately too. I mean it's sort of relevant to discuss whether
> column info is good for -g modes because it'll impact whether -g modes
> hurt -Rpass diagnostic quality... though if that's really a big deal
> we could probably have a mode where column info is added but not used
> for actual debug info emission.
> _______________________________________________
> cfe-commits mailing list
> cfe-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>



-- 
Alexey Samsonov
vonosmas at gmail.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20140623/f2359d84/attachment.html>