[llvm-dev] [RFC] Backend for Motorola 6800 series CPU (M68k)

[Fāng-ruì Sòng via llvm-dev]

On Sun, Nov 15, 2020 at 1:27 PM John Paul Adrian Glaubitz via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
>
> On 11/15/20 9:33 PM, Simon Pilgrim via llvm-dev wrote:
> > As well as the actual patch reviews, has there been official approval that the
> > M68k experimental backend can be added to trunk? I guess we need a
> > "Backend: M68k" bugzilla component - is there anything else?
>
> Sounds good. I'll file that bug tomorrow.
>
> Thanks,
> Adrian
>
> --
>  .''`.  John Paul Adrian Glaubitz
> : :' :  Debian Developer - glaubitz at debian.org
> `. `'   Freie Universitaet Berlin - glaubitz at physik.fu-berlin.de
>   `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

I've looked at a few newer backends in LLVM and I think the policy is
unclear about how an experimental target is approved and reviewed.

* BPF https://lists.llvm.org/pipermail/llvm-dev/2014-December/079897.html
Tom said "it's up to Chris Lattner to approve new backends" I cannot
find discussions about the approval process around the time it was
committed (Jan 2015)
* ARC https://lists.llvm.org/pipermail/llvm-dev/2017-August/116268.html
"but it would be great to have this in tree" may be vaguely counted as
an
* VE I cannot find related llvm-dev discussions around the time it was
committed (Jan 2020)
* CSKY (a stub has been added)
https://lists.llvm.org/pipermail/llvm-dev/2020-August/144485.html The
closest thing to an approval is the sentence "It is always exciting to
see new targets!"

Also worth noting that some of the initial review patches have just
one or no reviewer on the reviewer list (i.e. probably not get enough
scrutiny from community members).
(In addition, our Phabricator setting makes a patch green if anyone
accepts it - this makes it seem like the target is approved while the
reviewer probably just intended that "the patch is in a good shape".
Sometimes the author committed it in haste after accepted. Sometimes
this may be understood as the author might have waited for too long
before getting feedback)