RFR: 8171855: Move package name transformations during module bootstrap into native code

[Claes Redestad]

Hi,

after a round of review comments I've now reworked this to do the
transformations in the JNI layer rather than inside the VM, with
similar - if not better - results.

Webrevs:
http://cr.openjdk.java.net/~redestad/8171855/hotspot.03/
http://cr.openjdk.java.net/~redestad/8171855/jdk.03/

Testing: RBT run in progress, all runtime/modules tests pass locally

Thanks!

/Claes

On 01/02/2017 07:27 PM, Claes Redestad wrote:
> Hi,
>
> during jigsaw bootstrap, package names - represented in external form,
> "java.lang" - are transformed into VM internal form, "java/lang",
> before calling into the VM.
>
> This, however, can effectively be moved into the VM, which removes the
> need to generate a lot of short-lived strings during bootstrap and heat
> up various String.replace-related methods.  This has a noticeable impact
> on startup metrics.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8171855
>