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

[Andrew Haley]

On 11/20/20 8:01 PM, Volker Simonis wrote:

> In another private mail you were mentioning that the aarch64 port
> which is intended for integration into 8u-dev will be based on
> IcedTea's HotSpot at 8u272 and is targeted for 8u282 in January. The
> Corretto team is very interested in having  the aarch64 port in 8u-dev
> and we want to offer some assistance if you think that could help? Do
> you already have a JBS issue to track this work?
>
> We are also interested in which compiler you will be using for
> building the aarch64 in 8u? We are currently building with GCC 7 but
> that still produces quite some warnings in shared code so we are
> interested in downporting changes from higher jdk versions which fix
> these warnings. This is even more important as we plan to move to gcc
> 10 eventually because that has support for the new ARM outline atomics
> [1] but that requires even more warning fixes. Using outline atomics
> in compiled code showed nice performance improvements in our
> benchmark results for some GC-heavy workloads.

I would be extremely sceptical about "fixing warnings" in a backport.
There has been a long and sorry history of warning fixes breaking
release code, and many warnings are bogus.

Unless a warning reveals a real bug or risky code, the code shouldn't be
changed.

-- 
Andrew Haley  (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
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