Native: fix @ExportObjCClass with the new memory manager

Previous implementation of `@ExportObjCClass` relied on the fact that
initialization of top-level fields was eager, i.e. happened during
Kotlin runtime initialization, when Kotlin code is accesses for the
first time.

With the new MM, initialization of top-level fields became lazy, it
happens when the particular file is accessed for the first time.

This commit fixes `@ExportObjCClass` with the new MM by making the
initialization of particular top-level fields eager.

^KT-53373 Fixed

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

@@ -127,7 +127,7 @@ private class InteropLoweringPart1(val context: Context) : BaseInteropIrTransfor
 
     lateinit var currentFile: IrFile
 
-    private val topLevelInitializers = mutableListOf<IrExpression>()
+    private val eagerTopLevelInitializers = mutableListOf<IrExpression>()
     private val newTopLevelDeclarations = mutableListOf<IrDeclaration>()
 
     override val irFile: IrFile
@@ -142,8 +142,8 @@ private class InteropLoweringPart1(val context: Context) : BaseInteropIrTransfor
         currentFile = irFile
         irFile.transformChildrenVoid(this)
 
-        topLevelInitializers.forEach { irFile.addTopLevelInitializer(it, context, false) }
-        topLevelInitializers.clear()
+        eagerTopLevelInitializers.forEach { irFile.addTopLevelInitializer(it, context, threadLocal = false, eager = true) }
+        eagerTopLevelInitializers.clear()
 
         irFile.addChildren(newTopLevelDeclarations)
         newTopLevelDeclarations.clear()
@@ -191,7 +191,7 @@ private class InteropLoweringPart1(val context: Context) : BaseInteropIrTransfor
 
         if (irClass.annotations.hasAnnotation(interop.exportObjCClass.fqNameSafe)) {
             val irBuilder = context.createIrBuilder(currentFile.symbol).at(irClass)
-            topLevelInitializers.add(irBuilder.getObjCClass(symbols, irClass.symbol))
+            eagerTopLevelInitializers.add(irBuilder.getObjCClass(symbols, irClass.symbol))
         }
     }
 

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/ir/util/IrUtils2.kt

@@ -62,7 +62,7 @@ internal fun irBuilder(
 
 private var topLevelInitializersCounter = 0
 
-internal fun IrFile.addTopLevelInitializer(expression: IrExpression, context: KonanBackendContext, threadLocal: Boolean) {
+internal fun IrFile.addTopLevelInitializer(expression: IrExpression, context: KonanBackendContext, threadLocal: Boolean, eager: Boolean) {
     val irField = IrFieldImpl(
             expression.startOffset, expression.endOffset,
             IrDeclarationOrigin.DEFINED,
@@ -79,6 +79,9 @@ internal fun IrFile.addTopLevelInitializer(expression: IrExpression, context: Ko
         if (threadLocal)
             annotations += buildSimpleAnnotation(context.irBuiltIns, startOffset, endOffset, context.ir.symbols.threadLocal.owner)
 
+        if (eager)
+            annotations += buildSimpleAnnotation(context.irBuiltIns, startOffset, endOffset, context.ir.symbols.eagerInitialization.owner)
+
         initializer = IrExpressionBodyImpl(startOffset, endOffset, expression)
     }
     addChild(irField)

kotlin-native/backend.native/tests/interop/objc/objcTests.def

@@ -1,6 +1,8 @@
 language = Objective-C
-headers = Foundation/NSArray.h Foundation/NSValue.h Foundation/NSString.h Foundation/NSStream.h Foundation/NSBundle.h
+headers = Foundation/NSArray.h Foundation/NSValue.h Foundation/NSString.h Foundation/NSStream.h Foundation/NSBundle.h \
+    objc/runtime.h
 headerFilter = **/interop/objc/tests/**.h \
     Foundation/NSArray.h Foundation/NSValue.h Foundation/NSString.h Foundation/NSStream.h \
-    objc/objc.h Foundation/NSBundle.h
+    objc/objc.h Foundation/NSBundle.h \
+    objc/runtime.h
 linkerOpts = -lobjctests

kotlin-native/backend.native/tests/interop/objc/tests/kt53373_1.kt

@@ -0,0 +1,5 @@
+import objcTests.*
+import kotlinx.cinterop.*
+
+@ExportObjCClass
+class KT53373 : NSObject()

kotlin-native/backend.native/tests/interop/objc/tests/kt53373_2.kt

@@ -0,0 +1,10 @@
+import kotlinx.cinterop.*
+import kotlin.test.*
+import objcTests.*
+
+@Test
+fun testKT53373() {
+    val kt53373Class = objc_lookUpClass("KT53373")
+    assertNotNull(kt53373Class)
+    assertEquals("KT53373", class_getName(kt53373Class)?.toKString())
+}