[jdk19] RFR: 8289091: move oop safety check from SharedRuntime::get_java_tid() to JavaThread::threadObj() [v3]

[Daniel D. Daugherty]

On Tue, 28 Jun 2022 16:55:29 GMT, Daniel D. Daugherty <dcubed at openjdk.org> wrote:

>> A trivial move of the oop safety check from SharedRuntime::get_java_tid() to
>> JavaThread::threadObj(). Also made adjustments to the threadObj() calls in
>> JavaThread::print_on_error() and JavaThread::get_thread_name_string() so
>> that we don't get secondary crashes when a JavaThread crashes after it has
>> detached the GC barrier.
>> 
>> Tested with Mach5 Tier[1-7]. A Mach5 Tier8 will be started this weekend.
>
> Daniel D. Daugherty has updated the pull request incrementally with one additional commit since the last revision:
> 
>   dholmes CR - use Thread::current() instead of Thread::current_or_null().

I've re-read the history behind:

[JDK-8132510](https://bugs.openjdk.org/browse/JDK-8132510) Replace ThreadLocalStorage with compiler/language-based thread-local variables

which is the fix that introduced `Thread::current_or_null_safe()`. Wow does that fix
and the code review process bring back memories. I remember the struggle to get
the fix in before JDK9 FC... 10 releases ago... yikes!

I'm mulling and researching on what to do...

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PR: https://git.openjdk.org/jdk19/pull/69