RFR: 8254315: Shenandoah: Concurrent weak reference processing [v2]

[Roman Kennke]

On Fri, 9 Oct 2020 17:07:04 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

>> Roman Kennke has updated the pull request incrementally with three additional commits since the last revision:
>> 
>>  - Add precompiled header to shenandoahMarkBitMap.cpp
>>  - Fix null-check after C2 native-LRB
>>  - Reinstate check for ShenandoahSelfFixing that got lost during the merge
>
> src/hotspot/share/oops/instanceRefKlass.hpp line 61:
> 
>> 59:   InstanceRefKlass() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
>> 60:
>> 61:   virtual bool is_instance_ref_klass()        const { return true; }
> 
> Don't make this change.  There already exists an idiom for testing for reference klasses.
> 
> k->is_instance_klass() && (InstanceKlass::cast(k)->reference_type() != REF_NONE)

Thanks, Kim! I didn't actually intend to open this up for review, and have reverted it back to 'draft' status. Thank
you anyway for the suggestion: it is one of the things that I wanted to ask you guys about. I will make that change,
thank you!

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PR: https://git.openjdk.java.net/jdk/pull/505