Implement JVM_IsImplicitlyConstructibleClass

runtime/j9vm/javanextvmi.cpp

@@ -741,8 +741,23 @@ JVM_IsValhallaEnabled()
 JNIEXPORT jboolean JNICALL
 JVM_IsImplicitlyConstructibleClass(JNIEnv *env, jclass cls)
 {
-	assert(!"JVM_IsImplicitlyConstructibleClass unimplemented");
-	return JNI_FALSE;
+	jboolean result = JNI_FALSE;
+	J9VMThread *currentThread = (J9VMThread *)env;
+	J9InternalVMFunctions const * const vmFuncs = currentThread->javaVM->internalVMFunctions;
+	vmFuncs->internalEnterVMFromJNI(currentThread);
+	if (NULL == cls) {
+		vmFuncs->setCurrentException(currentThread, J9VMCONSTANTPOOL_JAVALANGNULLPOINTEREXCEPTION, NULL);
+	} else {
+		J9Class *clazz = J9VM_J9CLASS_FROM_JCLASS(currentThread, cls);
+		J9ROMClass *romClass = clazz->romClass;
+		if (J9_ARE_ALL_BITS_SET(romClass->optionalFlags, J9_ROMCLASS_OPTINFO_IMPLICITCREATION_ATTRIBUTE)
+			&& J9_ARE_ALL_BITS_SET(getImplicitCreationFlags(romClass), J9AccImplicitCreateHasDefaultValue)
+		) {
+			result = JNI_TRUE;
+		}
+	}
+	vmFuncs->internalExitVMToJNI(currentThread);
+	return result;
 }
 
 JNIEXPORT jboolean JNICALL

test/functional/Valhalla/playlist.xml

@@ -318,6 +318,7 @@
 		</variations>
 		<command>$(JAVA_COMMAND) $(JVM_OPTIONS) \
 		--enable-preview \
+		--add-exports java.base/jdk.internal.value=ALL-UNNAMED \
 		-cp $(Q)$(LIB_DIR)$(D)asm.jar$(P)$(RESOURCES_DIR)$(P)$(TESTNG)$(P)$(TEST_RESROOT)$(D)ValhallaTests.jar$(Q) \
 		org.testng.TestNG -d $(REPORTDIR) $(Q)$(TEST_RESROOT)$(D)testng.xml$(Q) -testnames ValhallaAttributeTests \
 		-groups $(TEST_GROUP) \

test/functional/Valhalla/src/org/openj9/test/lworld/ValhallaAttributeTests.java

@@ -21,6 +21,7 @@
  */
 package org.openj9.test.lworld;
 
+import jdk.internal.vm.annotation.ImplicitlyConstructible;
 import org.testng.annotations.Test;
 import org.testng.Assert;
 
@@ -196,4 +197,31 @@ static public void testPutStaticNullToNullRestrictedField() throws Throwable {
 		}
 		Assert.fail("Test expected a NullPointerException wrapped in ExceptionInInitializerError.");
 	}
+
+	@ImplicitlyConstructible
+	static value class ImplicitClass {
+		Object o;
+		ImplicitClass(Object o) {
+			this.o = o;
+		}
+	}
+
+	/* Test to verify JVM_IsImplicitlyConstructibleClass */
+	@Test
+	static public void testValueClassIsImplicitlyConstructible() {
+		ImplicitClass ic = (ImplicitClass)jdk.internal.value.ValueClass.zeroInstance(ImplicitClass.class);
+	}
+
+	static value class NonImplicitClass {
+		Object o;
+		NonImplicitClass(Object o) {
+			this.o = o;
+		}
+	}
+
+	/* Test to verify JVM_IsImplicitlyConstructibleClass */
+	@Test(expectedExceptions = IllegalArgumentException.class)
+	static public void testValueClassIsImplicitlyConstructible2() {
+		jdk.internal.value.ValueClass.zeroInstance(NonImplicitClass.class);
+	}
 }