[lworld] RFR: 8353432: [lworld] Deoptimization needs to handle nullable, flat fields in non-value class holders

[Quan Anh Mai]

On Sun, 1 Jun 2025 06:57:27 GMT, f <duke at openjdk.org> wrote:

>> Hi,
>> 
>> This patch adds handling of nullable flat fields in non-value class holder. Currently, we add all the fields to the safepoint, then add all the null markers. I decide to change this to adding the null marker of a flat field right after all the subfields of it. It makes the shape similar to how we pass nullable flat fields in the ABI, as well as simplifies the implementation since we do not have to keep track of all null markers when traversing the object payload.
>> 
>> Please take a look and leave your reviews, thanks a lot.
>
> Ok. I'll try, but this repo does not allow submit issues. Thank you.

@SidneyLann That's great, you can report an issue by sending an email to [valhalla-dev](https://mail.openjdk.org/mailman/listinfo/valhalla-dev).

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PR Comment: https://git.openjdk.org/valhalla/pull/1478#issuecomment-2926804110