RFR: 8316229: Enhance class initialization logging [v2]

[Aleksey Shipilev]

On Wed, 20 Sep 2023 02:09:22 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> This change adds some additional debug logging to the class linking and initialization process. It was useful in diagnosing the deadlock described by:
>> 
>> https://bugs.openjdk.org/browse/JDK-8316469
>> 
>> See the example output in JBS issue.
>> 
>> The changes are mostly uncontroversial but I needed to expose a way to access the init thread's name, which can't use the regular `name()` method as the safety check doesn't recognise the calling context as being safe.
>> 
>> Testing:
>>  - manual examination of logging output
>>  - ran the only test that enables class+init logging: runtime/logging/ClassInitializationTest.java (no change as expected)
>>  - tiers1-3 sanity
>> 
>> Thanks.
>
> David Holmes has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Extra space
>  - Put thread name in quotes.

Marked as reviewed by shade (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/15809#pullrequestreview-1635161132