Re: Using GNU make jobserver from GCC

[Jan Hubicka]

> > There's no question that you're right... if we're willing to change GNU
> > make to require threads (which today it does not).  Today GNU make can
> > work on pretty much any ISO89/POSIX.1-conforming system with virtually
> > all its functionality, which is a very low bar.  I don't feel confident
> > that (a) we should say make now requires a system with threading support
> > and whatever locking capabilities that would be needed with it, or (b)
> > we can ifdef out the requirement for threads without much more
> > complexity, or (c) we can separate the jobserver implementation from the
> > threading implementation.
> 
> We are talking about an advanced feature, required for other programs,
> such as GCC, to be able to interact with Make's jobserver.  If worse
> comes to worst, we can always say that this feature is optional and
> will work only if pthreads are available.  Like Guile support, for
> example, which also requires to install additional software.
> 
> That being said, since even GCC requires pthreads and many other
> libraries nowadays, I doubt that you could find many platforms we care
> about that don't have this functionality installed to begin with.

Note that I believe GCC is just first from common tools that would like
to use jobserver.  I don't think it will take long to LLVM/clang to threat
its compilation and gold AFAIK also supports parallel linking. So I really
think the convenient library to use in those tools would be important win.

It would be nice to support as many hosts as possible, but if we can't
get it right without threads and named pipes, I think it is very resonable
requirement for this feature (that is indeed somewhat advanced and may
stay not supported on more exotic OSes)

Honza