RFR(M): 8248359: Update JVMCI

[Vladimir Kozlov]

Looks good.

Thanks,
Vladimir

On 6/29/20 2:36 AM, Doug Simon wrote:
> Please review this webrev that ports a number of improvements to JVMCI in JDK 16 from jvmci-8 <https://github.com/graalvm/graal-jvmci-8>:
> 
> * Move C++ state and functionality associated with a HotSpotJVMCIRuntime Java object into its peer JVMCIRuntime C++ object (e.g., the _shared_library_javavm moves from being a static field in JVMCIEnv to an instance field in JVMCIRuntime).
> * The management of JNI globals handles and Metadata handles passed to JVMCI Java code should also be moved to JVMCIRuntime.
> * Introduce tracing of low frequency JVMCIRuntime lifetime events (e.g. JVMCIRuntime lifetime phase events) at less verbose trace level.
> * Trace high frequency JVMCI events (e.g. CompilerToVM calls) at more verbose trace level.
> * Detect unsupported jvmci.* system properties and use fuzzy matching for an error message suggesting closely matching supported properties.
> * Improve javadoc for HotSpotJVMCIRuntime.attachCurrentThread.
> * Reduce calls to JavaThread::current() in conjunction with JNIAccessMark.
> 
> https://bugs.openjdk.java.net/browse/JDK-8248359
> https://dougxc.github.io/webrevs/8248359_16.01
> 
> Testing: hs-tier1,hs-tier2,hs-tier3-graal
> 
> -Doug
>