[8u-dev] Request for Approval: 8139273: Small improvements to DynamicLinker and DynamicLinkerFactory

Attila Szegedi szegedia at gmail.com
Mon Dec 26 17:19:24 UTC 2016

Please approve.

Yes, this is a a cca. 15 month old changeset from jdk9 codebase. I was debugging something and discovered that the problem it fixes (DynamicLinker.getLinkedCallSiteLocation() giving incorrect results with -XX:+ShowHiddenFrames) still persists in jdk8. This change essentially makes the stack walking code in DynamicLinker.getLinkedCallSiteLocation() operate correctly when the JVM is run with -XX:+ShowHiddenFrames. 

This method itself is only used to generate location information in diagnostic messages and call tracing counters. This problem thus makes Nashorn generate incorrect call-site linkage miss counters (a performance diagnostic feature of Nashorn) with -XX:+ShowHiddenFrames.

The changeset also removes a deprecated method; this is safe as the method was never part of a public API and there have not been any internal uses of it for very long time (Nashorn internally uses its non-deprecated counterpart). Two never-subclassed, internal classes are also marked as final. I kept these changes too as they’re sensible, in order to not deviate from the already approved changeset.

Bug: https://bugs.openjdk.java.net/browse/JDK-8139273
jdk9 webrev: http://cr.openjdk.java.net/~attila/8139273/webrev.jdk9
jdk9 review thread: http://mail.openjdk.java.net/pipermail/nashorn-dev/2015-October/005394.html

Changes apply cleanly to jdk8u-dev after path reshuffling from modular source code layout.


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