Value class is indicated by missing ACC_IDENTITY

This change is needed to support @ImplicitlyConstructible and @NullRestricted annotations for functional tests. See #19459

In this change:
- J9ROMCLASS_IS_VALUE macro checks for ACC_IDENTITY flag instead of ACC_VALUE
- Remove J9AccValueType from codebase

There is more work to be done to fully remove ACC_VALUE (#18829) such as removing CFR_ACC_VALUE and adding runtime class file verification checks. Because functional value type tests are not able to run currently due to a recent update of the extensions repository I am making just a few changes toward getting those working.

I am also removing the assert in JVM_IsNullRestrictedArray which is triggered when building OpenJ9. This method can't be implemented right now because OpenJ9 doesn't have support for null restricted arrays yet. See #17340 #19460

Author: theresa-m

debugtools/DDR_VM/src/com/ibm/j9ddr/CompatibilityConstants29.dat

@@ -59,7 +59,7 @@ J9FieldFlags.J9FieldFlagIsNullRestricted = 0
 J9JavaAccessFlags.J9AccClassIsUnmodifiable = 0
 J9JavaAccessFlags.J9AccRecord = 0
 J9JavaAccessFlags.J9AccSealed = 0
-J9JavaAccessFlags.J9AccValueType = 0
+J9JavaAccessFlags.J9AccClassHasIdentity = 0
 J9JavaAccessFlags.J9StaticFieldIsNullRestricted = 0
 J9JavaAccessFlags.J9PutfieldNarrowing = 0
 J9JavaAccessFlags.J9StaticFieldRefBaseType = 0

debugtools/DDR_VM/src/com/ibm/j9ddr/vm29/pointer/helper/ValueTypeHelper.java

@@ -217,7 +217,7 @@ public J9ClassPointer findJ9ClassInFlattenedClassCacheWithSigName(J9ClassPointer
 
 		@Override
 		public boolean isRomClassAValueType(J9ROMClassPointer romClass) throws CorruptDataException {
-			return romClass.modifiers().allBitsIn(J9JavaAccessFlags.J9AccValueType);
+			return !romClass.modifiers().allBitsIn(J9JavaAccessFlags.J9AccClassHasIdentity);
 		}
 
 		@Override

runtime/bcutil/ClassFileOracle.cpp

@@ -277,15 +277,10 @@ ClassFileOracle::ClassFileOracle(BufferManager *bufferManager, J9CfrClassFile *c
 		_hasNonEmptyConstructor = true;
 	}
 
-	if (J9_ARE_ALL_BITS_SET(_classFile->accessFlags, CFR_ACC_VALUE_TYPE | CFR_ACC_IDENTITY)) {
-		_buildResult = InvalidValueType;
+	if (J9_ARE_ALL_BITS_SET(_classFile->accessFlags, CFR_ACC_IDENTITY)) {
+		_hasIdentityFlagSet = true;
 	} else {
-		if (J9_ARE_ALL_BITS_SET(_classFile->accessFlags, CFR_ACC_VALUE_TYPE)) {
-			_isValueType = true;
-		}
-		if (J9_ARE_ALL_BITS_SET(_classFile->accessFlags, CFR_ACC_IDENTITY)) {
-			_hasIdentityFlagSet = true;
-		}
+		_isValueType = true;
 	}
 #endif /* defined(J9VM_OPT_VALHALLA_VALUE_TYPES) */
 

runtime/j9vm/javanextvmi.cpp

@@ -743,7 +743,7 @@ JVM_IsImplicitlyConstructibleClass(JNIEnv *env, jclass cls)
 JNIEXPORT jboolean JNICALL
 JVM_IsNullRestrictedArray(JNIEnv *env, jobject obj)
 {
-	assert(!"JVM_IsNullRestrictedArray unimplemented");
+	// TODO implement this with https://github.com/eclipse-openj9/openj9/issues/19460
 	return JNI_FALSE;
 }
 

runtime/oti/j9javaaccessflags.h

@@ -46,7 +46,6 @@
 #define J9AccSuper                         0x00000020 /* class */
 #define J9AccClassHasIdentity              0x00000020 /* class */
 #define J9AccSynchronized                  0x00000020 /* method */
-#define J9AccValueType                     0x00000040 /* class(Valhalla) */
 #define J9AccBridge                        0x00000040 /* method */
 #define J9AccVolatile                      0x00000040 /* field */
 #define J9AccVarArgs                       0x00000080 /* method */

runtime/oti/j9modifiers_api.h

@@ -88,7 +88,7 @@
  * TODO: Will need to modify this if ValObject/RefObject proposal goes through.
  * Some exiting places using J9ROMCLASS_IS_VALUE() may need to check J9ROMCLASS_IS_PRIMITIVE_VALUE_TYPE().
  */
-#define J9ROMCLASS_IS_VALUE(romClass)	_J9ROMCLASS_SUNMODIFIER_IS_SET((romClass), J9AccValueType)
+#define J9ROMCLASS_IS_VALUE(romClass)	!_J9ROMCLASS_SUNMODIFIER_IS_SET((romClass), J9AccClassHasIdentity)
 #else /* J9VM_OPT_VALHALLA_VALUE_TYPES */
 #define J9ROMCLASS_IS_VALUE(romClass)	FALSE
 #endif /* J9VM_OPT_VALHALLA_VALUE_TYPES */
@@ -140,7 +140,7 @@
 
 /* Class instances are allocated via the new bytecode */
 #define J9ROMCLASS_ALLOCATES_VIA_NEW(romClass) \
-	J9_ARE_NO_BITS_SET((romClass)->modifiers, J9AccAbstract | J9AccInterface | J9AccClassArray | J9AccValueType)
+	J9_ARE_NO_BITS_SET((romClass)->modifiers, J9AccAbstract | J9AccInterface | J9AccClassArray)
 
 /* Class instances are allocated via J9RAMClass->totalInstanceSize */
 #define J9ROMCLASS_ALLOCATE_USES_TOTALINSTANCESIZE(romClass) \

runtime/vm/ClassInitialization.cpp

@@ -607,7 +607,7 @@ classInitStateMachine(J9VMThread *currentThread, J9Class *clazz, J9ClassInitStat
 								/* A NullRestricted field must be in a value class with an
 								* ImplicitCreation attribute. The attribute must have the ACC_DEFAULT flag set.
 								*/
-								if (J9_ARE_NO_BITS_SET(entryRomClass->modifiers, J9AccValueType)
+								if (!J9ROMCLASS_IS_VALUE(entryRomClass)
 									|| J9_ARE_NO_BITS_SET(entryRomClass->optionalFlags, J9_ROMCLASS_OPTINFO_IMPLICITCREATION_ATTRIBUTE)
 									|| J9_ARE_NO_BITS_SET(getImplicitCreationFlags(entryRomClass), J9AccImplicitCreateHasDefaultValue)
 								) {

runtime/vm/createramclass.cpp

@@ -2011,7 +2011,7 @@ loadFlattenableFieldValueClasses(J9VMThread *currentThread, J9ClassLoader *class
 						* ImplicitCreation attribute. The attribute must have the ACC_DEFAULT flag set.
 						* Static fields will be checked during class preparation.
 						*/
-						if (J9_ARE_NO_BITS_SET(valueROMClass->modifiers, J9AccValueType)
+						if (!J9ROMCLASS_IS_VALUE(valueROMClass)
 							|| J9_ARE_NO_BITS_SET(valueROMClass->optionalFlags, J9_ROMCLASS_OPTINFO_IMPLICITCREATION_ATTRIBUTE)
 							|| J9_ARE_NO_BITS_SET(getImplicitCreationFlags(valueROMClass), J9AccImplicitCreateHasDefaultValue)
 						) {
@@ -2331,30 +2331,20 @@ internalCreateRAMClassDone(J9VMThread *vmThread, J9ClassLoader *classLoader, J9C
 		}
 
 #if defined(J9VM_OPT_VALHALLA_VALUE_TYPES)
-		if (J9_ARE_ALL_BITS_SET(classFlags, J9ClassHasIdentity)) {
-			if (J9ROMCLASS_IS_VALUE(romClass)) {
-				J9UTF8* className = J9ROMCLASS_CLASSNAME(romClass);
-				J9UTF8 *superclassName = J9ROMCLASS_SUPERCLASSNAME(romClass);
-				setCurrentExceptionNLSWithArgs(vmThread, J9NLS_VM_VALUETYPE_HAS_WRONG_SUPERCLASS,
-						J9VMCONSTANTPOOL_JAVALANGINCOMPATIBLECLASSCHANGEERROR, J9UTF8_LENGTH(className),
-						J9UTF8_DATA(className), J9UTF8_LENGTH(superclassName), J9UTF8_DATA(superclassName));
-			}
-		} else {
-			if (J9ROMCLASS_HAS_IDENTITY(romClass)) {
-				classFlags |= J9ClassHasIdentity;
-			}
+		if (J9ROMCLASS_HAS_IDENTITY(romClass)) {
+			classFlags |= J9ClassHasIdentity;
 		}
 
 #if defined(J9VM_OPT_VALHALLA_FLATTENABLE_VALUE_TYPES)
-	if (J9_ARE_ALL_BITS_SET(romClass->optionalFlags, J9_ROMCLASS_OPTINFO_IMPLICITCREATION_ATTRIBUTE)) {
-		U_16 implicitCreationFlags = getImplicitCreationFlags(romClass);
-		if (J9_ARE_ALL_BITS_SET(implicitCreationFlags, J9AccImplicitCreateNonAtomic)) {
-			classFlags |= J9ClassAllowsNonAtomicCreation;
-		}
-		if (J9_ARE_ALL_BITS_SET(implicitCreationFlags, J9AccImplicitCreateHasDefaultValue)) {
-			classFlags |= J9ClassAllowsInitialDefaultValue;
+		if (J9_ARE_ALL_BITS_SET(romClass->optionalFlags, J9_ROMCLASS_OPTINFO_IMPLICITCREATION_ATTRIBUTE)) {
+			U_16 implicitCreationFlags = getImplicitCreationFlags(romClass);
+			if (J9_ARE_ALL_BITS_SET(implicitCreationFlags, J9AccImplicitCreateNonAtomic)) {
+				classFlags |= J9ClassAllowsNonAtomicCreation;
+			}
+			if (J9_ARE_ALL_BITS_SET(implicitCreationFlags, J9AccImplicitCreateHasDefaultValue)) {
+				classFlags |= J9ClassAllowsInitialDefaultValue;
+			}
 		}
-	}
 #endif /* defined(J9VM_OPT_VALHALLA_FLATTENABLE_VALUE_TYPES) */
 
 		if (J9ROMCLASS_IS_VALUE(romClass)) {