On Tue, Jun 24, 2025 at 08:53:03AM +1000, Jonathan Gray wrote:
> On Mon, Jun 23, 2025 at 08:31:45PM +0200, Mark Kettenis wrote:
> > > Date: Mon, 23 Jun 2025 18:25:17 +0200
> > > From: Moritz Buhl <mb...@openbsd.org>
> > >
> > > Dear bugs@,
> > >
> > > for about two weeks I am having trouble running x11/alacritty on
> > > my Apple MacBook Air M2 from 2022.
> > > I suspect there is a missing BTI instruction in libmesas jit.
> >
> > Yup!
> >
> > So the big question is whether it is the Mesa update or the LLVM
> > update that broke it. The LLVM update was committed 12 days ago, so
> > "about two weeks" could mean it is or it isn't :(.
>
> Mesa still has the local change to add and call
>
> extern "C" void
> lp_set_module_branch_protection(LLVMModuleRef MRef)
> {
> /* Enable standard (bti+pac-ret) branch protection */
> llvm::Module *M = llvm::unwrap(MRef);
> M->addModuleFlag(llvm::Module::Override, "branch-target-enforcement", 1);
> M->addModuleFlag(llvm::Module::Override, "sign-return-address", 1);
> }
It seems LLVM 19 needs it set for function attributes after
https://github.com/llvm/llvm-project/commit/e15d67cfc2e5775cc79281aa860f3ad3be628f39
