Merge pull request #21518 from tajila/vtbackport

(0.51) Disable fast JNI wait if wait can unmount continuations.

Author: pshipton

runtime/vm/FastJNI.cpp

@@ -79,7 +79,7 @@ removePrefixes(J9JVMTIData *jvmtiData, U_8 **methodNameData, UDATA *methodNameLe
 		if ((j9env->flags & J9JVMTIENV_FLAG_RETRANSFORM_CAPABLE) == retransformFlag) {
 			jint prefixCount = j9env->prefixCount;
 			char *prefix = j9env->prefixes;
-	
+
 			/* Remove the prefixes */
 			while (0 != prefixCount) {
 				size_t prefixLength = strlen(prefix);
@@ -145,6 +145,17 @@ jniNativeMethodProperties(J9VMThread *currentThread, J9Method *jniNativeMethod,
 						UDATA entryLength = methodDescriptor->methodNameLength;
 						if (J9UTF8_DATA_EQUALS(methodNameData, methodNameLength, entryData, entryLength)) {
 found:
+#if JAVA_SPEC_VERSION >= 24
+							/* Fast implementation located - if wait can unmount the continuation, check to see if this
+							 * native is the wait implememnation and reject it if so.
+							 */
+							if (J9_ARE_ANY_BITS_SET(currentThread->javaVM->extendedRuntimeFlags3, J9_EXTENDED_RUNTIME3_YIELD_PINNED_CONTINUATION)
+							&& J9UTF8_LITERAL_EQUALS(methodName, methodNameLength, "waitImpl")
+							&& J9UTF8_LITERAL_EQUALS(methodSignature, methodSignatureLength, "(JI)V")
+							) {
+								goto done;
+							}
+#endif /* JAVA_SPEC_VERSION >= 24 */
 							address = methodDescriptor->function;
 							flags = methodDescriptor->flags;
 							Trc_VM_fastJNINativeFound(