RFR: 8138659: Speed up InstanceKlass subclass discrimination (original) (raw)

Kim Barrett kim.barrett at oracle.com
Tue Oct 6 15:59:13 UTC 2015

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 rightnbits() and bitfield functions in globalDefinitions.hpp that would make some bit manipulation in this setkind() 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.

Minor comment: I'd put kindisinstance() .. kindisclassloader() 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/

Testing: JPRT

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