8366488: JVM_FindClassFromClass should assert that from class is never null

[Arraying]

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

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Issue

• JDK-8366488: JVM_FindClassFromClass should assert that from class is never null (Enhancement - P4)

Reviewers

• David Holmes (@dholmes-ora - Reviewer)

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8366488: JVM_FindClassFromClass should assert that from class is never null

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[dholmes-ora]

I agree with the analysis - the value can never be null based on the current code paths.

Thanks