Integrated: 8304303: implement VirtualThread class notifyJvmti methods as C2 intrinsics

[Serguei Spitsyn]

On Thu, 16 Mar 2023 05:03:51 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

> This is needed for future performance/scalability improvements in JVMTI support of virtual threads.
> The update includes the following:
> 
> 1. Refactored the `VirtualThread` native methods:
>     `notifyJvmtiMountBegin`     and `notifyJvmtiMountEnd`      => `notifyJvmtiMount`
>     `notifyJvmtiUnmountBegin` and `notifyJvmtiUnmountEnd` => `notifyJvmtiUnmount`
> 2. Still useful implementation of old native methods is moved from `jvm.cpp` to `jvmtiThreadState.cpp`:
>      `JVM_VirtualThreadMountStart`       => `VTMS_mount_begin`
>      `JVM_VirtualThreadMountEnd`         => `VTMS_mount_end`
>      `JVM_VirtualThreadUnmountStart`  = > `VTMS_unmount_begin`
>      `JVM_VirtualThreadUnmountEnd`    => `VTMS_mount_end`
> 3. Intrinsified the `VirtualThread` native methods: `notifyJvmtiMount`, `notifyJvmtiUnmount`, `notifyJvmtiHideFrames`.
> 4. Removed the`VirtualThread` static boolean state variable `notifyJvmtiEvents` and its support in `javaClasses`.
> 5. Added static boolean state variable `_VTMS_notify_jvmti_events` to the jvmtiVTMSTransitionDisabler class as a replacement of the `VirtualThread` `notifyJvmtiEvents` variable.
> 
> Implementing the same methods as C1 intrinsics can be needed in the future but is a low priority for now.  
> 
> Testing:
>  - Ran mach5 tiers 1-6. No regressions were found.

This pull request has now been integrated.

Changeset: bc0ed730
Author:    Serguei Spitsyn <sspitsyn at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/bc0ed730f2c9dad55d0046b4fe8c9cd623b6dbf8
Stats:     449 lines in 20 files changed: 276 ins; 125 del; 48 mod

8304303: implement VirtualThread class notifyJvmti methods as C2 intrinsics

Reviewed-by: vlivanov, lmesnik

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PR: https://git.openjdk.org/jdk/pull/13054