[llvm-dev] Python build dependency in LLVM and/or clang?

[Joerg Sonnenberger via llvm-dev]

On Wed, Jul 10, 2019 at 11:08:22AM -0500, Michael Kruse wrote:
> Am Fr., 5. Juli 2019 um 07:01 Uhr schrieb Joerg Sonnenberger via
> llvm-dev <llvm-dev at lists.llvm.org>:
> >
> > On Fri, Jul 05, 2019 at 10:43:12AM +0000, Simon Tatham via llvm-dev wrote:
> > > But before I do that, I wanted to check whether there would be any
> > > objection on grounds of build dependencies. Is it acceptable to require Python
> > > as part of the normal build process for LLVM?
> >
> > At the moment, Python is not truely necessary for building LLVM. The
> > cmake build system depends on it for some parts, but that's all. I would
> > be very sad for that to change.
> 
> llvm-build (LLVMBuild.txt) requires python. The LLVM build will abort with
> 
>    message(FATAL_ERROR
>     "Unable to find Python interpreter, required for builds and testing.
> 
>     Please install Python or specify the PYTHON_EXECUTABLE CMake variable.")
> 
> without it.

That's what I said. The cmake based build system needs it. LIT is
optional. It is entirely feasible to have a custom build system and no
Python at all. It would be quite painful to break that.

Joerg