[llvm] r219976 - Initial version of Go bindings.

[Peter Collingbourne]

On Tue, Oct 21, 2014 at 10:42:18PM +0000, Eric Christopher wrote:
> >
> >
> > > Honestly I didn't think about it much. It should probably get migrated
> > > along, because otherwise how would you pass that along?
> >
> > We might want the flag to appear in --cflags and --cxxflags. But it
> > shouldn't
> > appear in --cppflags, as that should contain only preprocessor flags.
> >
> >
> Sure.
> 
> 
> > > That said, stripping it out for now is fine. cgo should probably learn
> > how
> > > to deal with .dwo files at some point.
> >
> > Perhaps, but I'd expect that if cgo uses cppflags on its own it should be
> > able to rely on those flags not changing the output format.
> >
> >
> I'd be surprised if -g wasn't making it in there then since they're relying
> on debug output?
> 
> What's the actual command line look being passed to files that cgo wants?

We found that it looked like this:

gcc -w -Wno-error -o.../_cgo_.o -gdwarf-2 -c -xc -I.../include -I.../include -D_GNU_SOURCE -gsplit-dwarf -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I .../_obj_test/ -m64 -

It appears that many of these flags (including -gdwarf-2) come from cgo
itself, while the rest come from the user's c*flags.

http://golang.org/src/cmd/cgo/gcc.go#L743

That's probably the only way things could possibly work, as it's certainly
possible for the user's c*flags to not include any -g flags.

Thanks,
-- 
Peter