[Mesa-dev] [PATCH 1/2] meson: fix LLVM version detection when <= 3.4

[Eric Engestrom]

On Wednesday, 2018-02-28 17:02:50 +0000, Eric Engestrom wrote:
> On Wednesday, 2018-02-28 17:52:05 +0200, Andres Gomez wrote:
> > 3 digits versions in LLVM only started from 3.4.1 on. Hence, if you
> > have installed 3.4 or below, meson will fail even when we may not make
> > use of LLVM.
> > 
> > Cc: Dylan Baker <dylan at pnwbakers.com>
> > Cc: Eric Engestrom <eric.engestrom at imgtec.com>
> > Signed-off-by: Andres Gomez <agomez at igalia.com>
> > ---
> >  meson.build | 13 ++++++++++++-
> >  1 file changed, 12 insertions(+), 1 deletion(-)
> > 
> > diff --git a/meson.build b/meson.build
> > index 308f64cf811..b8c0b04893c 100644
> > --- a/meson.build
> > +++ b/meson.build
> > @@ -1037,7 +1037,18 @@ if with_llvm
> >    # that for our version checks.
> >    # svn suffixes are stripped by meson as of 0.43, and git suffixes are
> >    # strippped as of 0.44, but we support older meson versions.
> > -  _llvm_patch = _llvm_version[2]
> > +
> > +  # 3 digits versions in LLVM only started from 3.4.1 on
> > +  if dep_llvm.version() <= '3.3'
> 
> The correct 'meson way' to compare version strings is
>   if dep_llvm.version().version_compare('<= 3.3')
> 
> > +    _llvm_patch = _llvm_version[1]
> > +  elif dep_llvm.version() >= '3.5'
> > +    _llvm_patch = _llvm_version[2]
> > +  elif dep_llvm.version().startswith('3.4.1') or dep_llvm.version().startswith('3.4.2')
> > +    _llvm_patch = _llvm_version[2]
> > +  else
> > +    _llvm_patch = _llvm_version[1]
> > +  endif
> 
> This whole logic seems overly complicated, and I don't think duplicating
> the minor version as the patch version is the right thing either.
> How about this instead?
> 
>   if dep_llvm.version().version_compare('>= 3.4.1')
>     _llvm_patch = _llvm_version[2]
>   else
>     _llvm_patch = '0'
> 	endif

Actually, do we still support llvm < 3.4? Didn't we just bump the
minimum to 4.0?
I think we did, in which case this patch is not necessary at all :)

> 
> > +
> >    if _llvm_patch.endswith('svn')
> >      _llvm_patch = _llvm_patch.split('s')[0]
> >    elif _llvm_patch.contains('git')
> > -- 
> > 2.15.1
> >