Re: how to mark llvm* forbidden?

On Wed, Apr 05, 2017 at 06:18:37PM -0700, Russell L. Carter wrote:
> On 04/05/17 15:32, Chris H wrote:
> > On Wed, 5 Apr 2017 21:51:40 +0000 Brooks Davis <brooks_at_freebsd.org> wrote
> > 
> >> On Wed, Apr 05, 2017 at 11:42:16AM -0700, Chris H wrote:
> >>> OK I'm chasing -CURRENT, and I performed an initial
> >>> install, followed by a new world/kernel && ports about a
> >>> mos ago. Last Friday, I svn upped the system (src && ports),
> >>> rebuilt/installed world/kernel. I just began rebuilding
> >>> the ports, only to find that when finished, I will likely
> >>> end up with every version of llvm && clang from version 3
> >>> to the now current 4. My build session is currently tying
> >>> nearly every core on the CPU with llvm builds. Given that
> >>> llvm4 comes in base. Is there *any* reason I can not insist
> >>> that the ports I upgrade, or build, just use the version(s)
> >>> of clang/llvm in base? If so. How do I inform the ports
> >>> that they may *only* use the version(s) in base?
> >>
> >> In general you can't.  There are many reasons including: the base llvm
> >> doesn't include the requisite cmake bits for cmake based ports, some
> >> ports use unstable APIs and require specific LLVM versions, and some use
> >> LLVM tools or libraries that aren't built/installed as part of the base
> >> system.
> >>
> >> There are probably some ports where the base clang is fine but that's
> >> probably mostly down to someone getting USES variables right.
> >>
> >> -- Brooks
> > Grumble.. That's what I was afraid I might hear.
> > 
> > Thanks, Brooks! Even if it's not what I was hoping to hear. :)
> 
> FWIW, this is biting me hard right now too.  I feel your
> pain...  I'm a c++17 junky but I might have to let go of
> llvm-devel.

If you want to track clang development, I would generally dis-recommend
the llvm-devel port.  If you check out from upstream svn/git and build
with cmake and ninja, then you get pretty efficient incremental builds.
One nice think about the llvm build infrastructure is that you can use
it in place in the build's bin directory so you don't even need to
maintain an installed copy.

-- Brooks