Re: Tuple and changes for m68k with -malign-int

[Jeffrey Walton <noloader@gmail.com>]

On Tue, Aug 29, 2023 at 5:53 PM Karoly Balogh via Libc-help
<libc-help@sourceware.org> wrote:
>
> On Tue, 29 Aug 2023, John Paul Adrian Glaubitz wrote:
>
> > > I don't want to force anyone here, but I'd also be fine with that. The only
> > > downside, apart from compatibility, appears to be slightly increased memory
> > > usage, and you're not exactly going to run modern Linux with 8MB RAM anyway.
> >
> > Agreed. And I finally want to be able to use Rust and LLVM on m68k ;-).
>
> So, let me get this straight (or from anothe perspective if you will) -
> neither LLVM and Rust is ready for prime time, because it can't accomodate
> a decade old established standard on our platform. But Linux maintainers
> rush forward, and break^Wchange the ABI, so we can accomodate some
> half-baked fancy new tools.

Regarding Rust, it is only guaranteed to work on x86_64 and Aarch64.
Other platforms are a roll of the dice. See
https://doc.rust-lang.org/nightly/rustc/platform-support.html.

In practice, we had to scrap a project that was based on Rust. It gave
us too many problems on armel, armhf, aarch64 and powerpc. Rust could
not even compile its own cargos. We rebooted and went back to C. (This
was several years ago, before Aarch64 became Tier I).

> Sometime later someone realizes: if you want to support any other system
> on m68k (Amiga, Atari, 68k Mac, *BSD, game consoles (embedded) you name
> it), you still need to add support for the original alignment
> restrictions, because on those systems you're not always going to be able
> recompile the $world. So that someone will have the skills to add the
> needed changes to these tools, so they can finally mature and accommodate
> more real world scenarios that are out there.
>
> At that point Linux m68k broke their own ABI for no reason, but because
> someone couldn't wait until the necessary work was done, instead of
> hacking problems around.

Jeff