RFR: 8138659: Speed up InstanceKlass subclass discrimination

[Coleen Phillimore]

On 10/6/15 11:59 AM, Kim Barrett wrote:
> On Oct 5, 2015, at 4:02 PM, Coleen Phillimore <coleen.phillimore at oracle.com> wrote:
>>
>> In http://cr.openjdk.java.net/~kbarrett/8138659/webrev.00/src/share/vm/oops/instanceKlass.hpp.udiff.html
>>
>> There are right_n_bits() and bitfield functions in globalDefinitions.hpp that would make some bit manipulation in this set_kind() easier to read.
> I tried to do that, but ran into signed vs unsigned warning problems,
> because I used unsigned types here but the globalDefinitions.hpp
> bitfield operations are wired for signed types.  I believe unsigned is
> right for the changes I'm making, and I don't feel like generalizing
> the bitfield operations today.
>
> I did make a couple of small tweaks for readability though.

Okay, I don't know how much more readable they are but they're fine.
>
>> Minor comment: I'd put kind_is_instance() .. kind_is_class_loader() functions on one line each and not use so much vertical space.
> I reformatted the second (ordinary member function) block, but left
> the first (static member function) block alone because the line
> lengths became a little excessive for my taste.
>
> New full and incremental webrevs:
> http://cr.openjdk.java.net/~kbarrett/8138659/webrev.01/
> http://cr.openjdk.java.net/~kbarrett/8138659/webrev.01.inc/

These changes are fine with me.

Thanks,
Coleen
> Testing: JPRT
>