RFR (S) 8164692: InstanceKlass::_previous_version_count goes negative

[Coleen Phillimore]

Thank you, Dan for the quick review.

On 8/30/16 5:32 PM, Daniel D. Daugherty wrote:
> On 8/30/16 2:49 PM, Coleen Phillimore wrote:
>> Summary: decrement previous_version_count when it's removed from the 
>> list.
>>
>> The previous_version_count was decremented in the wrong place. This 
>> contributed to the bug that Dean's just sent out the RFR and the fix 
>> is essentially contributed by Dean.
>>
>> Ran jdk/test/java/lang/instrument, and internal closed (colocated and 
>> non-colocated) redefinition tests.
>>
>> open webrev at http://cr.openjdk.java.net/~coleenp/8164692.01/webrev
>
> src/share/vm/classfile/classLoaderData.cpp
>     L965: // and only if class redefinition and if there are previous 
> versions of
>         Perhaps:
>
>         // and only if class redefinition occurred and if there are 
> previous versions of

Yes, that's better grammar.
>
> src/share/vm/oops/instanceKlass.cpp
>     No comments.
>
> src/share/vm/oops/instanceKlass.hpp
>     No comments.
>
> test/runtime/RedefineTests/RedefineCount.java
>     L48: // previous_version_list and the count should stay zero, but 
> not go negative
>
>         Perhaps:
>
>             "should stay zero and not go negative"
>
>         for that last part.

Also clearer and more precise.
>
> Does the new test (RedefineCount.java) reproduce the crash that Dean L
> is chasing in https://bugs.openjdk.java.net/browse/JDK-8156137?
>

No, it doesn't reproduce the crash but it does hit my new assert in 
instanceKlass.hpp without the changes in instanceKlass.cpp.
> Thumbs up!
>

Thanks!
Coleen

> Dan
>
>
>> bug link https://bugs.openjdk.java.net/browse/JDK-8164692
>>
>>
>> Thanks,
>> Coleen
>