AARCH64 support for lworld

Tobias Hartmann tobias.hartmann at oracle.com
Tue Oct 23 08:58:42 UTC 2018

Hi Dmitry,

LW1 EA is already out for quite a while [1]. Here's a webrev of the changes from September:

We are currently working on LW2, which will re-introduce Q-Types:

Best regards,

[1] https://jdk.java.net/valhalla/

On 23.10.18 10:36, Dmitry Samersoff wrote:
> Tobias,
> As soon as lw1 is out ...
> Is there a webrev of changes between lw1 and plain hotspot?
> -Dmitry
> On 03.09.2018 11:33, Tobias Hartmann wrote:
>> 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:
>> http://cr.openjdk.java.net/~thartmann/valhalla/hs_changes/
>> Unfortunately, it's very outdated but I will hopefully find some time to update it soon.
>> Best regards,
>> Tobias
>> 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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