[K/N][IR] Never consider a enum a final class

Unfortunately, neither descriptors nor Lazy IR have enough information
to correctly deduce a enum's modality as psi2ir does, so to avoid the RTTI generator
generating different vtables in different setups (whether a klib is cached or not),
conservatively consider all enums non-final.

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/ir/NewIrUtils.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.backend.konan.ir
 
 import org.jetbrains.kotlin.backend.common.atMostOne
+import org.jetbrains.kotlin.backend.common.ir.isFinalClass
 import org.jetbrains.kotlin.backend.konan.DECLARATION_ORIGIN_INLINE_CLASS_SPECIAL_FUNCTION
 import org.jetbrains.kotlin.backend.konan.descriptors.allOverriddenFunctions
 import org.jetbrains.kotlin.backend.konan.descriptors.isInteropLibrary
@@ -62,9 +63,6 @@ val IrFunction.isOverridable get() = this is IrSimpleFunction && this.isOverrida
 val IrFunction.isOverridableOrOverrides
     get() = this is IrSimpleFunction && (this.isOverridable || this.overriddenSymbols.isNotEmpty())
 
-val IrClass.isFinalClass: Boolean
-    get() = modality == Modality.FINAL
-
 fun IrClass.isSpecialClassWithNoSupertypes() = this.isAny() || this.isNothing()
 
 inline fun <reified T> IrDeclaration.getAnnotationArgumentValue(fqName: FqName, argumentName: String): T? {

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/llvm/KotlinObjCClassInfoGenerator.kt

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.backend.konan.llvm
 import llvm.LLVMLinkage
 import llvm.LLVMSetLinkage
 import llvm.LLVMValueRef
+import org.jetbrains.kotlin.backend.common.ir.isFinalClass
 import org.jetbrains.kotlin.backend.konan.*
 import org.jetbrains.kotlin.backend.konan.descriptors.getAnnotationStringValue
 import org.jetbrains.kotlin.backend.konan.ir.*

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/InteropLowering.kt

@@ -13,7 +13,6 @@ import org.jetbrains.kotlin.backend.konan.cgen.*
 import org.jetbrains.kotlin.backend.konan.descriptors.allOverriddenFunctions
 import org.jetbrains.kotlin.backend.konan.descriptors.synthesizedName
 import org.jetbrains.kotlin.backend.konan.ir.*
-import org.jetbrains.kotlin.backend.konan.ir.isFinalClass
 import org.jetbrains.kotlin.backend.konan.llvm.IntrinsicType
 import org.jetbrains.kotlin.backend.konan.llvm.tryGetIntrinsicType
 import org.jetbrains.kotlin.backend.konan.serialization.resolveFakeOverrideMaybeAbstract

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/NativeAnnotationImplementationTransformer.kt

@@ -5,9 +5,9 @@
 
 package org.jetbrains.kotlin.backend.konan.lower
 
+import org.jetbrains.kotlin.backend.common.ir.isFinalClass
 import org.jetbrains.kotlin.backend.common.lower.AnnotationImplementationTransformer
 import org.jetbrains.kotlin.backend.konan.*
-import org.jetbrains.kotlin.backend.konan.ir.isFinalClass
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.types.*
 import org.jetbrains.kotlin.ir.util.*

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/optimizations/DataFlowIR.kt

@@ -7,6 +7,7 @@ package org.jetbrains.kotlin.backend.konan.optimizations
 
 import org.jetbrains.kotlin.backend.konan.*
 import org.jetbrains.kotlin.backend.common.ir.allParameters
+import org.jetbrains.kotlin.backend.common.ir.isFinalClass
 import org.jetbrains.kotlin.backend.konan.descriptors.*
 import org.jetbrains.kotlin.backend.konan.descriptors.OverriddenFunctionInfo
 import org.jetbrains.kotlin.backend.konan.descriptors.implementedInterfaces
@@ -486,14 +487,12 @@ internal object DataFlowIR {
             }, data = null)
         }
 
-        private fun IrClass.isFinal() = modality == Modality.FINAL
-
         fun mapClassReferenceType(irClass: IrClass): Type {
             // Do not try to devirtualize ObjC classes.
             if (irClass.module.name == Name.special("<forward declarations>") || irClass.isObjCClass())
                 return Type.Virtual
 
-            val isFinal = irClass.isFinal()
+            val isFinal = irClass.isFinalClass
             val isAbstract = irClass.isAbstract()
             val name = irClass.fqNameForIrSerialization.asString()
             classMap[irClass]?.let { return it }
@@ -638,7 +637,7 @@ internal object DataFlowIR {
                     }
                     val bridgeTargetSymbol = if (isSpecialBridge || bridgeTarget == null) null else mapFunction(bridgeTarget)
                     val placeToFunctionsTable = !isAbstract && it !is IrConstructor && irClass != null
-                            && (it.isOverridableOrOverrides || bridgeTarget != null || function.isSpecial || !irClass.isFinal())
+                            && (it.isOverridableOrOverrides || bridgeTarget != null || function.isSpecial || !irClass.isFinalClass)
                     val symbolTableIndex = if (placeToFunctionsTable) module.numberOfFunctions++ else -1
                     val frozen = it is IrConstructor && irClass!!.isFrozen(context)
                     val functionSymbol = if (it.isExported())

kotlin-native/backend.native/tests/build.gradle

@@ -1362,6 +1362,12 @@ linkTest("enum_linkTest") {
     lib = "codegen/enum/linkTest_lib.kt"
 }
 
+linkTest("enum_openMethodNoOverrides") {
+    useGoldenData = true
+    source = "codegen/enum/openMethodNoOverrides_main.kt"
+    lib = "codegen/enum/openMethodNoOverrides_lib.kt"
+}
+
 task enum_varargParam(type: KonanLocalTest) {
     useGoldenData = true
     source = "codegen/enum/varargParam.kt"

kotlin-native/backend.native/tests/codegen/enum/openMethodNoOverrides_lib.kt

@@ -0,0 +1,10 @@
+/*
+ * Copyright 2010-2022 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the LICENSE file.
+ */
+
+enum class Foo {
+    Z;
+
+    open fun bar() = 42
+}

kotlin-native/backend.native/tests/codegen/enum/openMethodNoOverrides_main.kt

@@ -0,0 +1,6 @@
+/*
+ * Copyright 2010-2022 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the LICENSE file.
+ */
+
+fun main() = println(Foo.Z.bar())

kotlin-native/backend.native/tests/codegen/enum/openMethodNoOverrides_main.out

@@ -0,0 +1 @@
+42