Integrated: 8364111: InstanceMirrorKlass iterators should handle CDS and hidden classes consistently

[Aleksey Shipilev]

On Fri, 25 Jul 2025 12:01:00 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> See the bug for more investigation. I think the root cause is already fixed in one of the `InstanceMirrorKlass` iterators, but not in the other one. Additionally, only one iterator handles the hidden classes. Also, there is a stale comment about CMS that apparently prevents us from asserting `is_primitive`, which is not relevant anymore.
> 
> So this PR commons out the metadata handling on both iterators, which fixes the GenShen+CDS bug, likely fixes hidden classes bug somewhere, and prevents the omission like this from happening again.
> 
> Additional testing:
>  - [x] Linux x86_64 server fastdebug, Generational Shenandoah + CDS bugs are not reproducing now
>  - [x] Linux x86_64 server fastdebug, `tier1`
>  - [x] Linux x86_64 server fastdebug, `all`

This pull request has now been integrated.

Changeset: ebb7f5d3
Author:    Aleksey Shipilev <shade at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/ebb7f5d39be8497fc89e25d0905335102e12c063
Stats:     64 lines in 2 files changed: 32 ins; 30 del; 2 mod

8364111: InstanceMirrorKlass iterators should handle CDS and hidden classes consistently

Reviewed-by: stuefe, ayang, coleenp

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PR: https://git.openjdk.org/jdk/pull/26477