[lworld] RFR: 8366705: [lworld] Re-work of arrays meta-data [v4]

[Matias Saavedra Silva]

On Wed, 3 Sep 2025 20:36:42 GMT, Chen Liang <liach at openjdk.org> wrote:

>> src/hotspot/share/cds/dynamicArchive.cpp line 371:
>> 
>>> 369:       if (oak->is_refined_objArray_klass()) {
>>> 370:         oak = ObjArrayKlass::cast(oak->super());
>>> 371:       }
>> 
>> Why is this needed?
>
> I think this is probably to convert specialize array klasses to the ObjArrayKlass that map 1-1 to Java's classes.

We don't want to archive refined array klasses in the dynamic archive, that's why this code ensures we only hold onto the ObjArrayKlass. Without this, the static archive can hold some dimensions of the array klass while the dynamic archive can have others.

The method `setup_array_klasses` tries to link together these different dimensions but we run into some trouble because we have the ObjArrayKlass and the different flavors of refined array klasses. It's better to just avoid putting array klasses in the dynamic archive altogether.

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PR Review Comment: https://git.openjdk.org/valhalla/pull/1452#discussion_r2322609691