RFR: 8296323: JVMTI can_support_virtual_threads not available for agents loaded into running VM [v7]

[Serguei Spitsyn]

On Tue, 22 Nov 2022 20:57:16 GMT, Daniel D. Daugherty <dcubed at openjdk.org> wrote:

>> Serguei Spitsyn has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains eight additional commits since the last revision:
>> 
>>  - Merge branch 'master' into br19
>>    Merge
>>  - removed thread->vthread() != NULL from  JvmtiVirtualThreadEventMark constructor
>>  - minor update for unnamed threads in jvmti_common.h
>>  - fixed a trailing white space issue
>>  - extended VirtualThreadStartTest to support more configs; fixed issue in jvmtiExport.cpp
>>  - roll back unintended VirtualThread.java file update
>>  - simplified VirtualThreadStartTest
>>  - 8296323: JVMTI can_support_virtual_threads not available for agents loaded into running VM
>
> src/hotspot/share/prims/jvmtiExport.cpp line 202:
> 
>> 200:     JvmtiEventMark(thread) {
>> 201:     _jthread = to_jobject(thread->vthread());
>> 202:     assert(thread->vthread() != NULL || thread->threadObj() == NULL, "sanity check");
> 
> Seems a little strange to me that L202 is after L201. You're asserting
> that `thread->vthread() != NULL` after passing it to a `to_jobject()` call.

I do not think this matters.
But I will revert the order of these line to make you happy. :)
Thank you for looking at the fix!

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PR: https://git.openjdk.org/jdk/pull/11246