RFR: 8277216: Examine InstanceKlass::_misc_flags for concurrency issues [v3]

[David Holmes]

On Wed, 15 Dec 2021 20:06:41 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> Recent bug in misc_flags showed that they are not set concurrently and could cause bugs.  Most of the misc_flags are set at classfile parsing time or at a safepoint and never reset.  This change adds an assert that the flag is set once.  See CR for more details.
>> Tested with tier1-3.
>
> Coleen Phillimore 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 five additional commits since the last revision:
> 
>  - Merge branch 'master' into misc
>  - Fix typo.
>  - Move has_resolved_methods to access flags so can be set and tested concurretly.
>  - Move has_resolved_methods to access flags so can be set and tested concurretly.
>  - 8277216: Examine InstanceKlass::_misc_flags for concurrency issues

There is more potential for tightening things up around these flags, but the additional assertions are a step in the right direction even if they don't guard against all possible changes that could lead to breakage.

Thanks,
David

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Marked as reviewed by dholmes (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/6851