RFR: 8339701: Test TestPinCaseWithCFLH.java fails with -Xcomp

[Alan Bateman]

On Sun, 8 Sep 2024 15:30:21 GMT, SendaoYan <syan at openjdk.org> wrote:

> Hi all,
>   The newly added testcase `serviceability/jvmti/vthread/TestPinCaseWithCFLH/TestPinCaseWithCFLH.java` fails with `-Xcomp` jvm option. The jvm option `-Xcomp` will make `BackgroundCompilation` false. In this test, disable `BackgroundCompilation` will make `instrumentation` in `premain` throw `java.util.MissingResourceException` in some test  environments. If I add `Thread.sleep(1000)` or `System.gc();` before `instrumentation.addTransformer`, this test also passed with `-Xcomp`.
>    So, I think it's necessary add `-XX:+BackgroundCompilation` option for this test to make this test more robustness, to make this test run passed with `-Xcomp` option.
>   Test-fix only, no risk.

I assume the sleep or System.gc is just delaying the install of the transformer. I think this issue will require more investigation. The "main" method hasn't run so I assume the issue is nothing to do with virtual threads and the diagnostic option, instead it's the transformer being invoked for launcher classes and this seems to be racing with other initialization, leading to the ClassCircularityError.

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PR Comment: https://git.openjdk.org/jdk/pull/20906#issuecomment-2337582370