RFR (S): 8198561: Make oop and narrowOop always have their own class type

[Erik Österlund]

Hi Coleen,

Thanks for the review.

On 2018-02-26 20:55, coleen.phillimore at oracle.com wrote:
>
> Hi Erik,
>
> This looks great.   I assume that the generated code (for these 
> classes vs. oopDesc* and juint) comes out the same?

I assume so too. Or at least that the performance does not regress. 
Maybe I run some benchmarks to be sure since the question has been asked.

Thanks,
/Erik

> thanks,
> Coleen
>
> On 2/26/18 8:32 AM, Erik Österlund wrote:
>> Hi,
>>
>> Making oop sometimes map to class types and sometimes to primitives 
>> comes with some unfortunate problems. Advantages of making them 
>> always have their own type include:
>>
>> 1) Not getting compilation errors in configuration X but not Y
>> 2) Making it easier to adopt existing code to use Shenandoah equals 
>> barriers
>> 3) Recognize oops and narrowOops safely in template
>>
>> Therefore, I would like to make both oop and narrowOop always map to 
>> a class type consistently.
>>
>> Webrev:
>> http://cr.openjdk.java.net/~eosterlund/8198561/webrev.00/
>>
>> Bug:
>> https://bugs.openjdk.java.net/browse/JDK-8198561
>>
>> Thanks,
>> /Erik
>