RFD: Add Linux/AArch64 to the set of supported OpenJDK platforms

[Vladimir Kozlov]

On 10/2/14 8:50 AM, Andrew Haley wrote:
> https://bugs.openjdk.java.net/browse/JDK-8044552
> http://openjdk.java.net/jeps/8044552
>
> The AArch64 port has been complete for some time, and the rate of
> churn has slowed to the point where I believe it is stable enough to
> be moved into the mainline sources.  It has passed the full JCK on JDK
> 7 and 8, but as yet there is no JCK 9, so I can say nothing about
> that.  We are regularly testing using jtreg, Hadoop, and a bunch of
> other tests, and our results are similar to the same tests on x86.
>
> I hope that this process will be less involved and require less effort
> from approvers (at Oracle and elsewhere) than that for the Power PC
> port.  I believe this because there are few changes to shared code
> beyond the trivial #ifdefs for header files which appear in many
> places.  In a few places we've had to #ifdef out code which is in
> src/share but makes architectural assumptions which are not valid on
> AArch64.
>
> So, our proposal as detailed in the JEP is to create a staging forest
> which at the start will be a clone of the current JDK9.  This staging
> forest will have jcheck fully enabled (unlike the AArch64 development
> repositories).  We will then submit webrevs for approval to the
> appropriate groups, and then check them in to the staging forest.
>
> I presume that for each webrev it will be necessary to create a Jira
> Issue.

Yes and please add 'AARCH64:' prefix to jbs Summary line, like next for 
ppc64:

PPC64: (part 220): ConstantTableBase for calls between args and jvms

>
> A few questions arise:
>
> To which mailing lists should requests for approval be sent?  I'm
> guessing hotspot-dev for the HotSpot patches, and jdk9-dev for
> everything else.

Correct.

>
> What should the granularity of the webrevs be?  I don't think that any
> subset of the src/cpu/aarch64 directory would make sense, but it's a
> big bite to chew.

You can at least separate assembler/macroassembler+interpreter+runtime 
and c1+c2+stubs code. As I remember your shared changes are not big 
(mostly ifdefs) so it could be one.

>
> The JEP, which was based on that for the Power PC, talks about a more
> detailed Integration Plan in the AArch64 Port OpenJDK Wiki Space, but I
> have no plans beyond submitting webrevs for approval.
>
> Is there anything else we should do before creating issues and
> submitting webrevs?

Yes, I think the rest is our side. We need to create stage repo and 
assign our sponsor.

Thanks,
Vladimir

>
> Thanks,
> Andrew.
>