llvm dev - Nov 2020 - [RFC] Backend for Motorola 6800 series CPU (M68k)

Hi All,

Just a quick update on the Motorola 6800 backend: Based on the feedback,
"M68k" (with lowercase "k") will now be the canonical target
name and
"m68k" be the target triple name. I've updated all the patches
under review
to reflect this change.

I'm also asking for everyone's help to review all the patches.
/* Target independent changes */
1. https://reviews.llvm.org/D88385
2. https://reviews.llvm.org/D88386
/* M68k CodeGen */
3. https://reviews.llvm.org/D88389
4. https://reviews.llvm.org/D88390
5. https://reviews.llvm.org/D88391
6. https://reviews.llvm.org/D88392
/* M68k Clang supports*/
7. https://reviews.llvm.org/D88393
8. https://reviews.llvm.org/D88394
Especially the Clang part, so far no one has given it a pass.

We also had a simple roadmap here:
https://github.com/M680x0/M680x0-mono-repo/projects
Showing the prerequisites to become an experimental target and eventually,
an official target. We're currently struggling on setting up the buildbot
but I believe Adrian (CC-ed) is working on that. So I hope the patches can
be sorted out while waiting for the buildbot.

CC-ing Craig here since he might able to give some feedbacks

Thank you!
-Min

-- 
Min-Yih Hsu
Ph.D Student in ICS Department, University of California, Irvine (UCI).
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Hi Min!

On 11/3/20 6:10 PM, Min-Yih Hsu wrote:
> Showing the prerequisites to become an experimental target and eventually,
> an official target. We're currently struggling on setting up the
buildbot
> but I believe Adrian (CC-ed) is working on that. So I hope the patches can
> be sorted out while waiting for the buildbot.
The m68k machine is actually already up and running, I just need to set up
a buildbot worker which I will do tomorrow or the day after tomorrow.

root at akiko:~# uname -a
Linux akiko 5.10.0-rc1-183617-gd7f4e16357f6 #1 Mon Nov 2 12:06:55 CET 2020 m68k
GNU/Linux
root at akiko:~# cat /proc/cpuinfo 
CPU:            68040
MMU:            68040
FPU:            68040
Clocking:       1085.6MHz
BogoMips:       723.76
Calibration:    3618816 loops
root at akiko:~# free -h
              total        used        free      shared  buff/cache   available
Mem:          3.2Gi        36Mi       3.1Gi       1.0Mi        53Mi       3.1Gi
Swap:         4.0Gi          0B       4.0Gi
root at akiko:~#

This new type of emulation was made by QEMU contributions of Laurent Vivier who
is
going to give a talk on QEMU m68k this Friday at our next m68k meeting [1].

Adrian
> [1] http://m68k.info/
-- 
 .''`.  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

Hello Min!

On 11/3/20 7:38 PM, John Paul Adrian Glaubitz wrote:
> On 11/3/20 6:10 PM, Min-Yih Hsu wrote:
>> Showing the prerequisites to become an experimental target and
eventually,
>> an official target. We're currently struggling on setting up the
buildbot
>> but I believe Adrian (CC-ed) is working on that. So I hope the patches
can
>> be sorted out while waiting for the buildbot.
> 
> The m68k machine is actually already up and running, I just need to set up
> a buildbot worker which I will do tomorrow or the day after tomorrow.
I have requested the buildbot to be added now [1]. The worker is fully set up.

Adrian
> [1] https://reviews.llvm.org/D91031
-- 
 .''`.  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

Hello!

On 11/3/20 6:10 PM, Min-Yih Hsu wrote:
> Just a quick update on the Motorola 6800 backend: Based on the feedback,
> "M68k" (with lowercase "k") will now be the canonical
target name and
> "m68k" be the target triple name. I've updated all the
patches under review
> to reflect this change.
Are there any news on this? The M68k buildbot is ready to be enabled. It will
be enabled once the backend has been merged [1].

Adrian
> [1] https://reviews.llvm.org/D91031
-- 
 .''`.  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

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?

On 13/11/2020 22:41, John Paul Adrian Glaubitz via llvm-dev
wrote:
> Hello!
>
> On 11/3/20 6:10 PM, Min-Yih Hsu wrote:
>> Just a quick update on the Motorola 6800 backend: Based on the
feedback,
>> "M68k" (with lowercase "k") will now be the
canonical target name and
>> "m68k" be the target triple name. I've updated all the
patches under review
>> to reflect this change.
> Are there any news on this? The M68k buildbot is ready to be enabled. It
will
> be enabled once the backend has been merged [1].
>> [1] https://reviews.llvm.org/D91031