[13] RFR(S): 8218201: Failures when vmIntrinsics::_getClass is not inlined

Tobias Hartmann tobias.hartmann at oracle.com
Thu Mar 7 13:23:57 UTC 2019

Thanks Claes!

Best regards,

On 07.03.19 14:23, Claes Redestad wrote:
> Looks good, and nice touch cleaning up the unused return values!
> /Claes
> On 2019-03-07 13:54, Tobias Hartmann wrote:
>> Hi,
>> please review the following patch:
>> https://bugs.openjdk.java.net/browse/JDK-8218201
>> http://cr.openjdk.java.net/~thartmann/8218201/webrev.00/
>> When intrinsification is disabled, the BCEscapeAnalyzer marks the return value of the (native)
>> method Object::getClass as "return allocated value" which means that "only newly allocated unescaped
>> objects are returned". The OptimizePtrCompare optimization then uses this information to incorrectly
>> fold 'obj.getClass() == Object.class' (see TestGetClass.java:39) to always false.
>> This is a very old issue and I can't trace back why a special case for the _getClass intrinsic has
>> been added to the BCEscapeAnalyzer. Since I don't think we should make any assumptions about the
>> returned Object, I've removed the special case.
>> Thanks,
>> Tobias

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