AARCH64 support for lworld

Tobias Hartmann tobias.hartmann at oracle.com
Mon Sep 3 08:33:58 UTC 2018

Hi Dmitry,

we use the "repo-valhalla" affects and fix version for value type related bugs/enhancements, so it
would make sense if you create an enhancement in this category and also add the label "lworld".

Great that you plan to port this work to Aarch64!

Some background information from the JIT side: The current implementation should be platform
independent except for the calling convention changes. These are:
1) Pass value types as fields (-XX:+ValueTypePassFieldsAsArgs)
2) Return value types as fields (-XX:+ValueTypeReturnedAsFields)
3) Special entry point for nullable value types (JDK-8209134)

1) and 2) are currently disabled and need to be reworked for value types. I plan to work on this in
the near future but you can safely ignore these for now (you will most likely get some build
failures due to interface changes though that you need to fix). 3) was added just recently with
(JDK-8209134) and should be straight forward to port.

Here is a webrev of all the hotspot changes we did:

Unfortunately, it's very outdated but I will hopefully find some time to update it soon.

Best regards,

On 03.09.2018 09:46, Dmitry Samersoff wrote:
> Hello Everybody,
> I started implementation of AARCH64 support for lworld.
> I'm on very early stage so any advices are highly appreciated.
> Should I file a CR for this task somewhere? What is correct way to do it?
> -Dmitry

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