RFR(XS) 8249719: MethodHandle performance suffers from bad ResolvedMethodTable hash function

[Andrei Pangin]

Hi,

Please review a small fix to a not-so-small performance issue that we've
seen when migrating a production application from JDK 8 to JDK 14.

On certain workloads, where Nashorn produces thousands MethodHandles,
ResolvedMethodTable operations become extremely slow due to degenerate
hashcode. This patch basically fixes hashcode by including the method
holder's name in the computation. More details in the bug report.

CR: https://bugs.openjdk.java.net/browse/JDK-8249719
Webrev: https://cr.openjdk.java.net/~apangin/8249719/webrev/

Tested: tier1-2, hotspot*runtime

I'll be glad if someone could sponsor the patch.

Thank you,
Andrei Pangin