RFR [1/3]: 8057038 Speculative traps not robust when compilation and class unloading are concurrent

[Peter Zhelezniakov]

Hi,

This is the first backport request in a series of 3: [1], [2], [3]. These fixes introduce atomicity and mutexes to Hotspot code. They help address crashes that occur in Apache Geode when running on a server with tens of CPU cores.
The patch from jdk9 did not apply as is, some contextual changes were needed.
This fix had a flaw that was later identified and fixed under [2]. Request for [2] is coming next in the series.
Testing: Hotspot JTreg tests.
JBS issue: https://bugs.openjdk.java.net/browse/JDK-8057038
Webrev: http://cr.openjdk.java.net/~avoitylov/peterz/8057038/8057038/

Thanks!
Peter

[1] https://bugs.openjdk.java.net/browse/JDK-8057038
[2] https://bugs.openjdk.java.net/browse/JDK-8139247
[3] https://bugs.openjdk.java.net/browse/JDK-8231501