On Dec 17, 2013, at 12:15, David Blaikie <[email protected]> wrote:
> > > > On Mon, Dec 16, 2013 at 8:06 PM, Adrian Prantl <[email protected]> wrote: > > On Dec 16, 2013, at 4:54 PM, Greg Clayton <[email protected]> wrote: > > > > > On Dec 16, 2013, at 2:55 PM, David Blaikie <[email protected]> wrote: > > > >> > >> > >> > >> On Mon, Dec 16, 2013 at 2:44 PM, Adrian Prantl <[email protected]> wrote: > >> Hi Chandler and David, > >> > >> unfortunately it looks more like case 1. This optimization breaks several > >> assumptions that tools in our software stack depend on. > >> > >> It's a fairly substantial debug info size savings that seems worth > >> investigating whether you can keep it enabled at least in > >> > >> - For example, it breaks dtrace, which on Darwin relies on being able to > >> pull the (complete) CTF info (compact C type format) out of the DWARF in > >> the .dSYM for a given module. > >> > >> I take it you're already using -fno-limit-debug-info for these scenarios, > >> then? (are you using -flimit-debug-info at all?) > > > > Yes, this is what will need to happen now that clang has changed. > > In case this wasn't clear enough: Currently, this optimization is totally > orthogonal to limited debug info. Passing -fno-limit-debug-info will not make > any of these examples work. This thread is about adding an additional flag to > the frontend that controls this optimization. > > I guess we could make also it part of -flimit-debug-info, either way will > work. > > Agreed. Though I'd rather separate it from -flimit-debug-info. > -flimit-debug-info is more aggressive. But, yes, for this particular kernel > scenario, if you do end up needing to disable the vtable-based optimization, > you should already be disabling -flimit-debug-info. That (and making it a separate option) sounds reasonable to me. -- adrian _______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
