RFR: 8366488: JVM_FindClassFromClass should assert that from class is never null [v2]

[Coleen Phillimore]

On Tue, 28 Oct 2025 14:02:06 GMT, Paul Hübner <phubner at openjdk.org> wrote:

>> Hi all,
>> 
>> The `from_class` nullcheck  in `JVM_FindClassFromClass` is redundant, as the this is the Java mirror which cannot be null during class linking/verification [1]. Therefore, it has been refactored to be an assertion instead.
>> 
>> Testing: tiers 1-4 Linux (x64, AArch64), macOS (x64, AArch64), Windows (x64). As part of a separate experiment, I've also run tiers 1-6 on x64 Linux with a non-null assertion before we call `Verifier::inference_verify` (which in turn, eventually, calls this code).
>> 
>> [1] For reasoning, see https://bugs.openjdk.org/browse/JDK-8366488
>
> Paul Hübner has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Turn conditional into assert.

Looks good!

-------------

Marked as reviewed by coleenp (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/27957#pullrequestreview-3389228968