RFR: 8308819: add JDWP and JDI virtual thread support for ThreadReference.ForceEarlyReturn [v2]

[Serguei Spitsyn]

On Tue, 30 May 2023 19:32:11 GMT, Chris Plummer <cjplummer at openjdk.org> wrote:

>> Improve ThreadReference.ForceEarlyReturn to support virtual threads as long as they are suspended and mounted.
>> 
>> [JDK-8308400](https://bugs.openjdk.org/browse/JDK-8308400) improved JVMTI ForceEarlyReturn support for virtual threads. The spec now says it is supported if the thread is suspended at an event (not a specific event as previously spec'd), and additional support may also be provided. The implementation now just requires that the virtual thread be mounted, so this covers being suspended at an event, but also other situations in which the virtual thread is mounted.
>> 
>> JDWP and JDI need to line up with JVMTI. Only spec changes will be needed.
>> 
>> A new test was added mostly to cover the unmounted virtual thread case that results in OpaqueFrameException.
>> 
>> forceEarlyReturn002 test had previously been updated for virtual threads to expect OpaqueFrameException. These changes have all been undone since the test now runs the same when using virtual threads as with platform threads.
>
> Chris Plummer has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Restore forceEarlyReturn() platform thread behaviour to only throw NativeMethodException and get rid of assert. A future CR/CSR will resolve the issue of OPAQUE_FRAME sometimes not meaning NativeMethodException for platform threads.

The fix looks good.
Thanks,
Serguei

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Marked as reviewed by sspitsyn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/14167#pullrequestreview-1451722916