[8u] RFR: JDK-8253036: Support building the Zero assembler port on AArch64

[Andrew Hughes]

On 15:04 Thu 17 Sep     , Aleksey Shipilev wrote:
> On 9/17/20 1:41 PM, Andrew Haley wrote:
> > On 17/09/2020 12:35, Aleksey Shipilev wrote:
> >   > On 9/17/20 12:49 PM, Aleksey Shipilev wrote:
> >   >> But hey, those definitions are missing even in the head JDK!
> >   >
> >   > Ha-ha. Oops. I have somewhat of the fix here:
> >   >     https://bugs.openjdk.java.net/browse/JDK-8253284
> >   >
> >   > ...that would have to trickle in separately.
> > 
> > OK. It doesn't seem right to me to enable AArch64/Zero in a update
> > version if we know it's incorrect, and quite nastily so. But I don't
> > mind if we can make sure that it gets fixed before it gets released.
> > GCC has all the atomic builtins we need to get this right; I don't
> > believe we need any platform-specific code at all.

I don't see this as a blocker to this patch. It is an improvement on
AArch64/Zero not building at all, a pre-requisite to getting the full
AArch64 port into 8u and produces an AArch64/Zero which is the same
as that on later JDKs.

> 
> Yeah, JDK-8253284 should trickle down as the usual backports until the Jan
> CPU. Reviews are appreciated there.

I've taken a look, but it is quite a confusing patch with the cleanup.
It's not helped by this new interface linking to five different patches.

> 
> I think (thankfully) that most distros ship the aarch64-port 8u bits in
> their aarch64 distributions, and therefore are not directly affected.

Well, yes, the plan is to get that into 8u282 as well. The aim of this
pre-requisite was to reduce the shared code changes in the AArch64 port
patch. As I said before, I was expecting there to be more to this,
including changes for other repos to recognise AArch64.

> 
> -- 
> Thanks,
> -Aleksey
> 

Thanks,
-- 
Andrew :)

Senior Free Java Software Engineer
OpenJDK Package Owner
Red Hat, Inc. (http://www.redhat.com)

PGP Key: ed25519/0xCFDA0F9B35964222 (hkp://keys.gnupg.net)
Fingerprint = 5132 579D D154 0ED2 3E04  C5A0 CFDA 0F9B 3596 4222