RFR: 8341273: JVMTI is not properly hiding some continuation related methods [v6]

[Alan Bateman]

On Fri, 18 Oct 2024 00:53:37 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

>> This fixes a problem in the VTMS (Virtual Thread Mount State) transition frames hiding mechanism.
>> Please, see a fix description in the first comment.
>> 
>> Testing:
>>  - Verified with new test `vthread/CheckHiddenFrames`
>>  - Mach5 tiers 1-6 are passed
>
> Serguei Spitsyn has updated the pull request incrementally with one additional commit since the last revision:
> 
>   review: clarify the use of annotation @JvmtiMountTransition in yield/yield0

src/java.base/share/classes/jdk/internal/vm/annotation/JvmtiMountTransition.java line 35:

> 33:  * The Continuation yield and yield0 frames normally are in VTMS transition
> 34:  * but can be found out of transition in an unmounted virtual thread.
> 35:  * This inconsistency is the reason why they also need this annotation.

In ChangesCurrentThread, Hidden and the other annotations, the description explains where they must be used. The JvmtiMountTransition description isn't very clear as it's explain why the Continuation yield methods need the annotation. It's okay if the description is re-worked in some future PR, my comment is just that the current description is very confusing.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21397#discussion_r1806047399