Improve interop with headers generated by Swift

Support `objc_runtime_name` attribute on Objective-C classes
thus enabling interop with `@objc` Swift classes without
explicitly specified name.

See https://github.com/JetBrains/kotlin-native/issues/1841#issuecomment-411346727

Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/Indexer.kt

@@ -60,7 +60,8 @@ private class ObjCProtocolImpl(
 private class ObjCClassImpl(
         name: String,
         override val location: Location,
-        override val isForwardDeclaration: Boolean
+        override val isForwardDeclaration: Boolean,
+        override val binaryName: String?
 ) : ObjCClass(name), ObjCContainerImpl {
     override val protocols = mutableListOf<ObjCProtocol>()
     override val methods = mutableListOf<ObjCMethod>()
@@ -302,12 +303,13 @@ internal class NativeIndexImpl(val library: NativeLibrary) : NativeIndex() {
 
         if (isObjCInterfaceDeclForward(cursor)) {
             return objCClassRegistry.getOrPut(cursor) {
-                ObjCClassImpl(name, getLocation(cursor), isForwardDeclaration = true)
+                ObjCClassImpl(name, getLocation(cursor), isForwardDeclaration = true, binaryName = null)
             }
         }
 
         return objCClassRegistry.getOrPut(cursor, {
-            ObjCClassImpl(name, getLocation(cursor), isForwardDeclaration = false)
+            ObjCClassImpl(name, getLocation(cursor), isForwardDeclaration = false,
+                    binaryName = getObjCBinaryName(cursor).takeIf { it != name })
         }) {
             addChildrenToObjCContainer(cursor, it)
         }
@@ -336,6 +338,14 @@ internal class NativeIndexImpl(val library: NativeLibrary) : NativeIndex() {
         }
     }
 
+    private fun getObjCBinaryName(cursor: CValue<CXCursor>): String {
+        val prefix = "_OBJC_CLASS_\$_"
+        val symbolName = clang_Cursor_getObjCManglings(cursor)!!.convertAndDispose()
+                .single { it.startsWith(prefix) }
+
+        return symbolName.substring(prefix.length)
+    }
+
     private fun getObjCCategoryAt(cursor: CValue<CXCursor>): ObjCCategoryImpl? {
         assert(cursor.kind == CXCursorKind.CXCursor_ObjCCategoryDecl) { cursor.kind }
 

Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/NativeIndex.kt

@@ -163,6 +163,7 @@ data class ObjCProperty(val name: String, val getter: ObjCMethod, val setter: Ob
 }
 
 abstract class ObjCClass(name: String) : ObjCClassOrProtocol(name) {
+    abstract val binaryName: String?
     abstract val baseClass: ObjCClass?
 }
 abstract class ObjCProtocol(name: String) : ObjCClassOrProtocol(name)

Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/Utils.kt

@@ -38,6 +38,14 @@ internal fun CValue<CXString>.convertAndDispose(): String {
     }
 }
 
+internal fun CPointer<CXStringSet>.convertAndDispose(): Set<String> = try {
+    (0 until this.pointed.Count).mapTo(mutableSetOf()) {
+        clang_getCString(this.pointed.Strings!![it].readValue())!!.toKString()
+    }
+} finally {
+    clang_disposeStringSet(this)
+}
+
 internal fun getCursorSpelling(cursor: CValue<CXCursor>) =
         clang_getCursorSpelling(cursor).convertAndDispose()
 

Interop/Runtime/src/native/kotlin/kotlinx/cinterop/ObjectiveCImpl.kt

@@ -94,7 +94,7 @@ typealias ObjCBlockVar<T> = ObjCNotImplementedVar<T>
 
 @Target(AnnotationTarget.CLASS)
 @Retention(AnnotationRetention.BINARY)
-annotation class ExternalObjCClass(val protocolGetter: String = "")
+annotation class ExternalObjCClass(val protocolGetter: String = "", val binaryName: String = "")
 
 @Target(AnnotationTarget.FUNCTION)
 @Retention(AnnotationRetention.BINARY)

Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/ObjCStubs.kt

@@ -505,21 +505,28 @@ abstract class ObjCContainerStub(stubGenerator: StubGenerator,
         val name = stubGenerator.kotlinFile.declare(classifier)
 
         val externalObjCClassAnnotationName = "@ExternalObjCClass"
-        val externalObjCClassAnnotation: String
 
-        if (container is ObjCProtocol) {
-            protocolGetter = if (metaContainerStub != null) {
-                metaContainerStub.protocolGetter!!
-            } else {
-                val nativeBacked = object : NativeBacked {}
-                // TODO: handle the case when protocol getter stub can't be compiled.
-                genProtocolGetter(stubGenerator, nativeBacked, container)
+        val externalObjCClassAnnotation: String = when (container) {
+            is ObjCProtocol -> {
+                protocolGetter = if (metaContainerStub != null) {
+                    metaContainerStub.protocolGetter!!
+                } else {
+                    val nativeBacked = object : NativeBacked {}
+                    // TODO: handle the case when protocol getter stub can't be compiled.
+                    genProtocolGetter(stubGenerator, nativeBacked, container)
+                }
+
+                externalObjCClassAnnotationName.applyToStrings(protocolGetter)
+            }
+            is ObjCClass -> {
+                protocolGetter = null
+                val binaryName = container.binaryName
+                if (binaryName != null) {
+                    externalObjCClassAnnotationName.applyToStrings("", binaryName)
+                } else {
+                    externalObjCClassAnnotationName
+                }
             }
-
-            externalObjCClassAnnotation = externalObjCClassAnnotationName.applyToStrings(protocolGetter)
-        } else {
-            protocolGetter = null
-            externalObjCClassAnnotation = externalObjCClassAnnotationName
         }
 
         this.classHeader = "$externalObjCClassAnnotation $keywords $name : $supersString"

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

@@ -5,9 +5,9 @@
 
 package org.jetbrains.kotlin.backend.konan
 
-import org.jetbrains.kotlin.backend.konan.descriptors.findPackage
 import org.jetbrains.kotlin.backend.konan.descriptors.findPackageView
 import org.jetbrains.kotlin.backend.konan.descriptors.getStringValue
+import org.jetbrains.kotlin.backend.konan.descriptors.getStringValueOrNull
 import org.jetbrains.kotlin.backend.konan.irasdescriptors.constructedClass
 import org.jetbrains.kotlin.backend.konan.irasdescriptors.getExternalObjCMethodInfo
 import org.jetbrains.kotlin.backend.konan.irasdescriptors.isReal
@@ -22,7 +22,6 @@ import org.jetbrains.kotlin.resolve.ExternalOverridabilityCondition
 import org.jetbrains.kotlin.resolve.constants.BooleanValue
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
 import org.jetbrains.kotlin.resolve.descriptorUtil.getAllSuperClassifiers
-import org.jetbrains.kotlin.resolve.descriptorUtil.module
 import org.jetbrains.kotlin.resolve.descriptorUtil.parentsWithSelf
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.TypeUtils
@@ -229,4 +228,15 @@ fun inferObjCSelector(descriptor: FunctionDescriptor): String = if (descriptor.v
             append(':')
         }
     }
-}
+}
+
+fun ClassDescriptor.getExternalObjCClassBinaryName(): String =
+        this.getExplicitExternalObjCClassBinaryName()
+                ?: this.name.asString()
+
+fun ClassDescriptor.getExternalObjCMetaClassBinaryName(): String =
+        this.getExplicitExternalObjCClassBinaryName()
+                ?: this.name.asString().removeSuffix("Meta")
+
+private fun ClassDescriptor.getExplicitExternalObjCClassBinaryName() =
+        this.annotations.findAnnotation(externalObjCClassFqName)!!.getStringValueOrNull("binaryName")

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

@@ -754,7 +754,7 @@ internal class FunctionGenerationContext(val function: LLVMValueRef,
             context.llvm.imports.add(irClass.llvmSymbolOrigin)
 
             if (irClass.isObjCMetaClass()) {
-                val name = irClass.name.asString().removeSuffix("Meta")
+                val name = irClass.descriptor.getExternalObjCMetaClassBinaryName()
 
                 val objCClass = load(codegen.objCDataGenerator!!.genClassRef(name).llvm)
 
@@ -766,7 +766,7 @@ internal class FunctionGenerationContext(val function: LLVMValueRef,
 
                 call(getClass, listOf(objCClass), exceptionHandler = exceptionHandler)
             } else {
-                load(codegen.objCDataGenerator!!.genClassRef(irClass.name.asString()).llvm)
+                load(codegen.objCDataGenerator!!.genClassRef(irClass.descriptor.getExternalObjCClassBinaryName()).llvm)
             }
         } else {
             if (irClass.isObjCMetaClass()) {

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

@@ -31,7 +31,7 @@ internal class KotlinObjCClassInfoGenerator(override val context: Context) : Con
 
         val superclassName = irClass.getSuperClassNotAny()!!.let {
             context.llvm.imports.add(it.llvmSymbolOrigin)
-            it.name.asString()
+            it.descriptor.getExternalObjCClassBinaryName()
         }
         val protocolNames = irClass.getSuperInterfaces().map {
             context.llvm.imports.add(it.llvmSymbolOrigin)