Merge pull request #21513 from fengxue-IS/051-jep491-GetCurrentContendedMonitor

(v0.51.0) Update GetCurrentContendedMonitor to support JEP491

Author: babsingh

runtime/jvmti/jvmtiThread.cpp

@@ -926,8 +926,9 @@ jvmtiGetCurrentContendedMonitor(jvmtiEnv *env,
 	rc = getCurrentVMThread(vm, &currentThread);
 	if (JVMTI_ERROR_NONE == rc) {
 		J9VMThread *targetThread = NULL;
+		J9InternalVMFunctions const * const vmFuncs = vm->internalVMFunctions;
 
-		vm->internalVMFunctions->internalEnterVMFromJNI(currentThread);
+		vmFuncs->internalEnterVMFromJNI(currentThread);
 
 		ENSURE_PHASE_LIVE(env);
 		ENSURE_CAPABILITY(env, can_get_current_contended_monitor);
@@ -944,35 +945,51 @@ jvmtiGetCurrentContendedMonitor(jvmtiEnv *env,
 #if JAVA_SPEC_VERSION >= 19
 			j9object_t threadObject = (NULL == thread) ? currentThread->threadObject : J9_JNI_UNWRAP_REFERENCE(thread);
 
-			/* Unmounted VirtualThread and CarrierThread with VirtualThread mounted cannot be contended. */
-			if (((NULL == targetThread) && IS_JAVA_LANG_VIRTUALTHREAD(currentThread, threadObject))
-			|| ((NULL != targetThread) && (threadObject == targetThread->carrierThreadObject) && (NULL != targetThread->currentContinuation))
-			) {
+			if ((NULL == targetThread) && IS_JAVA_LANG_VIRTUALTHREAD(currentThread, threadObject)) {
+#if JAVA_SPEC_VERSION >= 24
+				j9object_t continuationObject = J9VMJAVALANGVIRTUALTHREAD_CONT(currentThread, threadObject);
+
+				if (NULL != continuationObject) {
+					j9object_t syncObject = J9VMJDKINTERNALVMCONTINUATION_BLOCKER(currentThread, continuationObject);
+
+					/* Check if the Continuation.blocker field is set. */
+					if (NULL != syncObject) {
+						U_32 state = J9VMJAVALANGVIRTUALTHREAD_STATE(currentThread, threadObject);
+						if ((JVMTI_VTHREAD_STATE_BLOCKING == state) || (JVMTI_VTHREAD_STATE_BLOCKED == state)) {
+							rv_monitor = (jobject)vmFuncs->j9jni_createLocalRef((JNIEnv *)currentThread, syncObject);
+						}
+					}
+				}
+#endif /* JAVA_SPEC_VERSION >= 24 */
+				/* Prior to JDK24, an unmounted VirtualThread cannot be contended. */
+				goto release;
+			} else if ((NULL != targetThread) && (threadObject == targetThread->carrierThreadObject) && (NULL != targetThread->currentContinuation)) {
+				/* CarrierThread with VirtualThread mounted cannot be contended. */
 				goto release;
 			}
 #endif /* JAVA_SPEC_VERSION >= 19 */
 
 			/* CMVC 184481 - The targetThread should be suspended while we attempt to get its state. */
-			vm->internalVMFunctions->haltThreadForInspection(currentThread, targetThread);
+			vmFuncs->haltThreadForInspection(currentThread, targetThread);
 
 			vmstate = getVMThreadObjectStatesAll(targetThread, &lockObject, NULL, NULL);
 
 			if ((NULL != lockObject)
 			&& (OMR_ARE_NO_BITS_SET(vmstate, J9VMTHREAD_STATE_PARKED | J9VMTHREAD_STATE_PARKED_TIMED))
 			) {
-				rv_monitor = (jobject)vm->internalVMFunctions->j9jni_createLocalRef((JNIEnv *)currentThread, lockObject);
+				rv_monitor = (jobject)vmFuncs->j9jni_createLocalRef((JNIEnv *)currentThread, lockObject);
 			} else {
 				rv_monitor = NULL;
 			}
 
-			vm->internalVMFunctions->resumeThreadForInspection(currentThread, targetThread);
+			vmFuncs->resumeThreadForInspection(currentThread, targetThread);
 #if JAVA_SPEC_VERSION >= 19
 release:
 #endif /* JAVA_SPEC_VERSION >= 19 */
 			releaseVMThread(currentThread, targetThread, thread);
 		}
 done:
-		vm->internalVMFunctions->internalExitVMToJNI(currentThread);
+		vmFuncs->internalExitVMToJNI(currentThread);
 	}
 
 	if (NULL != monitor_ptr) {