[K/N] XCTest launcher for CompilerOutput's TEST_BUNDLE

This change adds a Native Obj-C launcher that implements XCTestCase
and overrides defaultTestSuite property to provide XCTest with generated
test suites and test cases.

The defaultTestSuite method is essentially a starting point with runtime
initialization. It requires a `Konan_create_testSuite()` method to be
implemented in a Kotlin library that returns a list of XCTestCases.

This launcher should be compiled as a TEST_BUNDLE to be used then with
XCTest.

This commit is a part of ^KT-58928


Co-authored-by: Alexander Shabalin <Alexander.Shabalin@jetbrains.com>

Merge-request: KT-MR-12841
Merged-by: Pavel Punegov <Pavel.Punegov@jetbrains.com>

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

@@ -93,11 +93,14 @@ private fun collectLlvmModules(generationState: NativeGenerationState, generated
     val additionalBitcodeFilesToLink = generationState.llvm.additionalProducedBitcodeFiles
     val exceptionsSupportNativeLibrary = listOf(config.exceptionsSupportNativeLibrary)
             .takeIf { config.produce == CompilerOutputKind.DYNAMIC_CACHE }.orEmpty()
+    val xcTestRunnerNativeLibrary = listOf(config.xcTestLauncherNativeLibrary)
+            .takeIf { config.produce == CompilerOutputKind.TEST_BUNDLE }.orEmpty()
     val additionalBitcodeFiles = nativeLibraries +
             generatedBitcodeFiles +
             additionalBitcodeFilesToLink +
             bitcodeLibraries +
-            exceptionsSupportNativeLibrary
+            exceptionsSupportNativeLibrary +
+            xcTestRunnerNativeLibrary
 
     val runtimeNativeLibraries = config.runtimeNativeLibraries
 

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

@@ -405,6 +405,9 @@ class KonanConfig(val project: Project, val configuration: CompilerConfiguration
     internal val objCNativeLibrary: String =
             File(distribution.defaultNatives(target)).child("objc.bc").absolutePath
 
+    internal val xcTestLauncherNativeLibrary: String =
+            File(distribution.defaultNatives(target)).child("xctest_launcher.bc").absolutePath
+
     internal val exceptionsSupportNativeLibrary: String =
             File(distribution.defaultNatives(target)).child("exceptionsSupport.bc").absolutePath
 

kotlin-native/runtime/build.gradle.kts

@@ -360,6 +360,15 @@ bitcode {
             }
         }
 
+        module("xctest_launcher") {
+            headersDirs.from(files("src/main/cpp"))
+
+            sourceSets {
+                main {}
+            }
+            onlyIf { target.family.isAppleFamily }
+        }
+
         testsGroup("custom_alloc_runtime_tests") {
             testedModules.addAll("custom_alloc")
             testSupportModules.addAll("main", "mm", "common_alloc", "common_gc", "common_gcScheduler", "manual_gcScheduler", "concurrent_ms_gc_custom", "objc")

kotlin-native/runtime/src/main/cpp/Runtime.h

@@ -7,6 +7,7 @@
 #define RUNTIME_RUNTIME_H
 
 #include "Porting.h"
+#include "Memory.h"
 
 #ifdef __cplusplus
 extern "C" {

kotlin-native/runtime/src/xctest_launcher/cpp/TestLauncher.h

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2010-2023 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.
+ */
+
+/**
+ * These are stub declarations from XCTest.framework needed for the launcher compilation.
+ * It makes possible to compile it without dependency on the framework, while the
+ * final build of the bundle should be done with a real XCTest.framework library.
+ */
+
+@interface XCTestCase
+@end
+
+@interface XCTestSuite
+@end
+
+@interface XCTestCase (XCTestSuiteExtensions)
+@property (class, readonly) XCTestSuite *defaultTestSuite;
+@end

kotlin-native/runtime/src/xctest_launcher/cpp/TestLauncher.mm

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2010-2023 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.
+ */
+
+#import "Memory.h"
+#import "ObjCExport.h"
+#import "TestLauncher.h"
+
+extern "C" OBJ_GETTER0(Konan_create_testSuite);
+
+@interface XCTestLauncher : XCTestCase
+@end
+
+@implementation XCTestLauncher
+/**
+ * Test suites factory.
+ *
+ * This is a starting point for XCTest to get test suites with test cases.
+ * K/N dynamically adds test suites for Kotlin tests.
+ * See `setupXCTestSuite` Kotlin method.
+ */
++ (id)defaultTestSuite {
+    kotlin::CalledFromNativeGuard guard;
+    ObjHolder holder;
+    return Kotlin_ObjCExport_refToObjC(Konan_create_testSuite(holder.slot()));
+}
+@end