On Tue, 24 Mar 2026 08:52:19 GMT, Yasumasa Suenaga <[email protected]> wrote:
> According to [Javadoc of > `jdk.incubator.vector.Vector`](https://docs.oracle.com/en/java/javase/26/docs/api/jdk.incubator.vector/jdk/incubator/vector/Vector.html), > vector classes are declared as value based class. However all vector classes > (e.g. `IntVector256`) do not have `@jdk.internal.ValueBased`, so > `DiagnoseSyncOnValueBasedClasses` does not affect if vector object are used > as a monitor. > > This PR fixes all of final classes of vector, but most of files were > generated by `gen-src.sh`. Essense of this PR is a chenge for > `X-VectorBits.java.template`. > After this change, we can see following logs if > `-XX:DiagnoseSyncOnValueBasedClasses` is set and vector class is used as > monitor object. > > > $ java --add-modules jdk.incubator.vector > -XX:DiagnoseSyncOnValueBasedClasses=2 ValueBaseLock > WARNING: Using incubator modules: jdk.incubator.vector > [0.453s][info][valuebasedclasses] Synchronizing on object 0x00000000823b1258 > of klass jdk.incubator.vector.IntVector256 > [0.453s][info][valuebasedclasses] at > ValueBaseLock.run(ValueBaseLock.java:9) > [0.453s][info][valuebasedclasses] - locked <0x00000000823b1258> (a > jdk.incubator.vector.IntVector256) > [0.453s][info][valuebasedclasses] at > java.lang.Thread.runWith(java.base@27-internal/Thread.java:1540) > [0.453s][info][valuebasedclasses] at > java.lang.Thread.run(java.base@27-internal/Thread.java:1527) Re-`@ValueBased`: 1. We need such an excerpt in every immediately annotated classes: * <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a> * class; programmers should treat instances that are * {@linkplain #equals(Object) equal} as interchangeable and should not * use instances for synchronization, or unpredictable behavior may * occur. For example, in a future release, synchronization may fail. 2. `VectorMask` and `VectorShuffle` should be marked so too. ------------- PR Comment: https://git.openjdk.org/jdk/pull/30392#issuecomment-4118867214
