Re: [Qemu-devel] converting build system to Meson?

[Peter Maydell]

On Thu, 7 Mar 2019 at 06:39, Thomas Huth <address@hidden> wrote:
> On 06/03/2019 19.12, Paolo Bonzini wrote:
> > lately I have been thinking of converting the QEMU build system to
> > Meson.  Meson is a relatively new build system that can replace
> > Autotools or hand-written Makefiles such as QEMU; as a die-hard
> > Autotools fan, I must say that Meson is by far better than anything else
> > that has ever tried to replace Autotools, and actually has the potential
> > to do so.
> >
> > Advantages of Meson that directly matter for QEMU include:[...]
>
> I'm not objecting a new build system per se, but could you elaborate on
>  problems of the current QEMU build system that will be fixed by this
> change? Since apart from some minor glitches (with the *.mak file
> dependencies for example), the current build system seems to work quite
> well for me ... so at least I currently don't feel enough pain yet to do
> such a big step, just because there is another new cool build system
> around...

Yes, that tends to be my view. Our current build system:
 * has no dependencies that are problematic for older hosts
   (contrast Meson, which needs Python 3.5, even if we take
   the drastic step of shipping an entire build tool along
   with QEMU; OSX python is 2.7 still)
 * is not particularly hard to deal with for the common cases
   ("add new source file" is straightforward)
 * covers all our requirements as far as I'm aware
   (whereas you've listed a couple of places where Meson
   would need changes/extensions to support things we do already)
 * is generally flexible enough to be hackable to deal with odd
   cases (it has escape mechanisms to generic-programmability,
   even if they're ugly and awkward)

So I think we'd need a more compelling reason to move right now.
(This might change in the future, eg if Meson catches on to the
extent that everybody is using it and competitors like CMake are
more obviously eclipsed by it, in the way that git took over
from svn and relegated mercurial and bzr to obscurity.)

thanks
-- PMM