RFR/RFC: C2: limited support for vbox/vunbox

Zoltán Majó zoltan.majo at oracle.com
Tue Jan 3 13:38:20 UTC 2017


Hi Tobias,


On 01/03/2017 09:35 AM, Tobias Hartmann wrote:
> Hi Zoltan,
>
> your changes look good to me!
>
> Here are some minor suggestions (you don't need to send another webrev):
> - in line 150 of ValueTypeTestBench.java you could use rI and rL to randomize the argument values
> - ValueCapableClass1::hash() is not used
> - ValueCapableClass1.java is missing the copyright header

thank you for the review! I fixed the problems you pointed out and 
pushed the changeset.

Best regards,


Zoltan

>
> Best regards,
> Tobias
>
> On 20.12.2016 15:33, Zoltán Majó wrote:
>> Hi,
>>
>>
>> this patch adds basic C2 support for the vbox/vunbox bytecodes.
>>
>> http://cr.openjdk.java.net/~zmajo/valhalla/02.vbox-vunbox.webrev.00/
>>
>> The suggested change is in a prototype phase, thus it works for only a limited set of use cases (covered by tests 37--40). In more detail, the patch
>> - does not enable C2 to generate checks currently performed by the interpreter to verify that the bytecodes handle a value-capable class and it's corresponding derived value type;
>> - relies on the assumption that the memory layout of the derived value type is the same as the memory layout of the value-capable class.
>>
>> The patch also contains a minor refactoring of method names in ValueTypeNode so that the names better match with the HotSpot Style Guide.
>>
>> I tested with ValueTypeTestBench.java and with the Octane+Nashorn benchmarks.
>>
>> Thank you!
>>
>> Best regards,
>>
>>
>> Zoltan
>>



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