[K/N][Tests] Fix: Crashes when casting to an Obj-C class companion

When generating section `__objc_classrefs`, need to consider distinguishing
`_OBJC_CLASS_$_` and `_OBJC_METACLASS_$_`

KT-65260

compiler/ir/ir.objcinterop/src/org/jetbrains/kotlin/ir/objcinterop/ObjCInterop.kt

@@ -266,9 +266,14 @@ fun IrClass.getExternalObjCClassBinaryName(): String =
         this.getExplicitExternalObjCClassBinaryName()
                 ?: this.name.asString()
 
-fun IrClass.getExternalObjCMetaClassBinaryName(): String =
-        this.getExplicitExternalObjCClassBinaryName()
-                ?: this.name.asString().removeSuffix("Meta")
+fun IrClass.getExternalObjCMetaClassBinaryName(): String {
+    this.getExplicitExternalObjCClassBinaryName()?.let { return it }
+    // External ObjC metaclass is named as `Foo.Componion`, Foo is subclass of NSObject or itself.
+    if (this.isCompanion) {
+        (this.parent as? IrClass)?.let { return it.name.asString() }
+    }
+    return this.name.asString().removeSuffix("Meta")
+}
 
 private fun IrClass.getExplicitExternalObjCClassBinaryName() =
-        this.annotations.findAnnotation(externalObjCClassFqName)!!.getAnnotationValueOrNull<String>("binaryName")
+        this.annotations.findAnnotation(externalObjCClassFqName)?.getAnnotationValueOrNull<String>("binaryName")

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

@@ -1331,7 +1331,7 @@ internal abstract class FunctionGenerationContext(
             generationState.dependenciesTracker.add(irClass)
             if (irClass.isObjCMetaClass()) {
                 val name = irClass.getExternalObjCMetaClassBinaryName()
-                val objCClass = getObjCClass(name)
+                val objCClass = getObjCClass(name, isMetaclass = true)
 
                 val getClass = llvm.externalNativeRuntimeFunction(
                         "object_getClass",
@@ -1364,7 +1364,8 @@ internal abstract class FunctionGenerationContext(
         }
     }
 
-    private fun getObjCClass(binaryName: String) = load(llvm.int8PtrType, codegen.objCDataGenerator!!.genClassRef(binaryName).llvm)
+    private fun getObjCClass(binaryName: String, isMetaclass: Boolean = false) =
+            load(llvm.int8PtrType, codegen.objCDataGenerator!!.genClassRef(binaryName, isMetaclass).llvm)
 
     fun getObjCClassFromNativeRuntime(binaryName: String): LLVMValueRef {
         generationState.dependenciesTracker.addNativeRuntime()

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

@@ -44,8 +44,9 @@ internal class ObjCDataGenerator(val codegen: CodeGenerator) {
         global.pointer
     }
 
-    fun genClassRef(name: String): ConstPointer = classRefs.getOrPut(name) {
-        val classGlobal = getClassGlobal(name, isMetaclass = false)
+    fun genClassRef(name: String, isMetaclass: Boolean = false): ConstPointer = classRefs.getOrPut(name) {
+        // Need to distinguish between _OBJC_CLASS_$_ and _OBJC_METACLASS_$_
+        val classGlobal = getClassGlobal(name, isMetaclass)
         val global = codegen.staticData.placeGlobal("OBJC_CLASSLIST_REFERENCES_\$_", classGlobal).also {
             it.setLinkage(LLVMLinkage.LLVMPrivateLinkage)
             it.setSection("__DATA,__objc_classrefs,regular,no_dead_strip")

native/native.tests/testData/codegen/cinterop/objc/kt65260.kt

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2010-2024 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+// TARGET_BACKEND: NATIVE
+// DISABLE_NATIVE: isAppleTarget=false
+@file:OptIn(kotlinx.cinterop.ExperimentalForeignApi::class)
+import platform.Foundation.*
+import platform.darwin.*
+import kotlin.test.*
+
+fun box(): String {
+    try {
+        // Test: cast to NSObject Metaclass
+        Any() as NSObject.Companion
+        // Test: cast to subclass of NSObject Metaclass
+        Any() as NSString.Companion
+        Any() as NSArray.Companion
+    } catch (e: Exception) {
+        // Cannot access 'TypeCastException': it is internal in Kotlin/Native.
+        assertTrue(e is ClassCastException)
+    }
+    return "OK"
+}