Re: Clang arm64 build is broken

From: Nick Desaulniers
Date: Mon May 14 2018 - 12:25:04 EST


On Fri, Apr 20, 2018 at 7:59 AM Andrey Konovalov <andreyknvl@xxxxxxxxxx>
wrote:
> On Fri, Apr 20, 2018 at 10:13 AM, Marc Zyngier <marc.zyngier@xxxxxxx>
wrote:
> >> The issue is that
> >> clang doesn't know about the "S" asm constraint. I reported this to
> >> clang [2], and hopefully this will get fixed. In the meantime, would
> >> it possible to work around using the "S" constraint in the kernel?
> >
> > I have no idea, I've never used clang to build the kernel. Clang isn't
> > really supported to build the arm64 kernel anyway (as you mention
> > below), and working around clang deficiencies would mean that we leave
> > with the workaround forever. I'd rather enable clang once it is at
> > feature parity with GCC.

> The fact that there are some existing issues with building arm64
> kernel with clang doesn't sound like a good justification for adding
> new issues :)

> However in this case I do believe that this is more of a bug in clang
> that should be fixed.

Just to follow up with this thread;

Support for "S" constraints is being (re-)added to Clang in:
https://reviews.llvm.org/D46745

--
Thanks,
~Nick Desaulniers