Implement very basic Objective-C interop

Also refactor StubGenerator

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

@@ -25,19 +25,47 @@ private class StructDeclImpl(spelling: String) : StructDecl(spelling) {
     override var def: StructDefImpl? = null
 }
 
-private class StructDefImpl(size: Long, align: Int, decl: StructDecl, hasNaturalLayout: Boolean) :
+private class StructDefImpl(
-        StructDef(size, align, decl, hasNaturalLayout) {
+        size: Long, align: Int, decl: StructDecl,
+        hasNaturalLayout: Boolean, hasUnalignedFields: Boolean
+) : StructDef(
+        size, align, decl,
+        hasNaturalLayout = hasNaturalLayout, hasUnalignedFields = hasUnalignedFields
+) {
 
     override val fields = mutableListOf<Field>()
 }
 
-private class EnumDefImpl(spelling: String, type: PrimitiveType) : EnumDef(spelling, type) {
+private class EnumDefImpl(spelling: String, type: Type) : EnumDef(spelling, type) {
     override val constants = mutableListOf<EnumConstant>()
 }
 
+private interface ObjCClassOrProtocolImpl {
+    val protocols: MutableList<ObjCProtocol>
+    val methods: MutableList<ObjCMethod>
+    val properties: MutableList<ObjCProperty>
+}
+
+private class ObjCProtocolImpl(name: String) : ObjCProtocol(name), ObjCClassOrProtocolImpl {
+    override val protocols = mutableListOf<ObjCProtocol>()
+    override val methods = mutableListOf<ObjCMethod>()
+    override val properties = mutableListOf<ObjCProperty>()
+}
+
+private class ObjCClassImpl(name: String) : ObjCClass(name), ObjCClassOrProtocolImpl {
+    override val protocols = mutableListOf<ObjCProtocol>()
+    override val methods = mutableListOf<ObjCMethod>()
+    override val properties = mutableListOf<ObjCProperty>()
+    override var baseClass: ObjCClass? = null
+}
+
 internal class NativeIndexImpl(val library: NativeLibrary) : NativeIndex() {
 
-    private data class DeclarationID(val usr: String)
+    private sealed class DeclarationID {
+        data class USR(val usr: String) : DeclarationID()
+        object VaListTag : DeclarationID()
+        object BuiltinVaList : DeclarationID()
+    }
 
     private val structById = mutableMapOf<DeclarationID, StructDeclImpl>()
 
@@ -49,21 +77,39 @@ internal class NativeIndexImpl(val library: NativeLibrary) : NativeIndex() {
     override val enums: List<EnumDef>
         get() = enumById.values.toList()
 
+    private val objCClassesByName = mutableMapOf<String, ObjCClassImpl>()
+
+    override val objCClasses: List<ObjCClass> get() = objCClassesByName.values.toList()
+
+    private val objCProtocolsByName = mutableMapOf<String, ObjCProtocolImpl>()
+
+    override val objCProtocols: List<ObjCProtocol> get() = objCProtocolsByName.values.toList()
+
     private val typedefById = mutableMapOf<DeclarationID, TypedefDef>()
 
     override val typedefs: List<TypedefDef>
         get() = typedefById.values.toList()
 
-    val functionByName = mutableMapOf<String, FunctionDecl>()
+    private val functionById = mutableMapOf<DeclarationID, FunctionDecl>()
 
     override val functions: List<FunctionDecl>
-        get() = functionByName.values.toList()
+        get() = functionById.values.toList()
 
     override val macroConstants = mutableListOf<ConstantDef>()
 
     private fun getDeclarationId(cursor: CValue<CXCursor>): DeclarationID {
         val usr = clang_getCursorUSR(cursor).convertAndDispose()
-        return DeclarationID(usr)
+        if (usr == "") {
+            val kind = cursor.kind
+            val spelling = getCursorSpelling(cursor)
+            return when (kind to spelling) {
+                CXCursorKind.CXCursor_StructDecl to "__va_list_tag" -> DeclarationID.VaListTag
+                CXCursorKind.CXCursor_TypedefDecl to "__builtin_va_list" -> DeclarationID.BuiltinVaList
+                else -> error(spelling)
+            }
+        }
+
+        return DeclarationID.USR(usr)
     }
 
     private fun getStructDeclAt(cursor: CValue<CXCursor>): StructDeclImpl {
@@ -91,8 +137,13 @@ internal class NativeIndexImpl(val library: NativeLibrary) : NativeIndex() {
         val type = clang_getCursorType(cursor)
         val size = clang_Type_getSizeOf(type)
         val align = clang_Type_getAlignOf(type).toInt()
-        val hasNaturalLayout = structHasNaturalLayout(cursor)
+
-        val structDef = StructDefImpl(size, align, structDecl, hasNaturalLayout)
+        val structDef = StructDefImpl(
+                size, align, structDecl,
+                hasNaturalLayout = structHasNaturalLayout(cursor),
+                hasUnalignedFields = structHasUnalignedFields(cursor)
+        )
+
         structDecl.def = structDef
 
         visitChildren(cursor) { childCursor: CValue<CXCursor>, _: CValue<CXCursor> ->
@@ -117,7 +168,7 @@ internal class NativeIndexImpl(val library: NativeLibrary) : NativeIndex() {
             val cursorType = clang_getCursorType(cursor)
             val typeSpelling = clang_getTypeSpelling(cursorType).convertAndDispose()
 
-            val baseType = convertType(clang_getEnumDeclIntegerType(cursor)) as PrimitiveType
+            val baseType = convertType(clang_getEnumDeclIntegerType(cursor))
 
             val enumDef = EnumDefImpl(typeSpelling, baseType)
 
@@ -137,11 +188,112 @@ internal class NativeIndexImpl(val library: NativeLibrary) : NativeIndex() {
         }
     }
 
+    private fun getObjCCategoryClassCursor(cursor: CValue<CXCursor>): CValue<CXCursor> {
+        assert(cursor.kind == CXCursorKind.CXCursor_ObjCCategoryDecl)
+        var classRef: CValue<CXCursor>? = null
+        visitChildren(cursor) { child, _ ->
+            if (child.kind == CXCursorKind.CXCursor_ObjCClassRef) {
+                classRef = child
+                CXChildVisitResult.CXChildVisit_Break
+            } else {
+                CXChildVisitResult.CXChildVisit_Continue
+            }
+        }
+
+        return clang_getCursorReferenced(classRef!!).apply {
+            assert(this.kind == CXCursorKind.CXCursor_ObjCInterfaceDecl)
+        }
+    }
+
+    private fun getObjCClassAt(cursor: CValue<CXCursor>): ObjCClassImpl {
+        assert(cursor.kind == CXCursorKind.CXCursor_ObjCInterfaceDecl) { cursor.kind }
+
+        val name = clang_getCursorDisplayName(cursor).convertAndDispose()
+
+        objCClassesByName[name]?.let { return it }
+
+        val result = ObjCClassImpl(name)
+        objCClassesByName[name] = result
+
+        addChildrenToClassOrProtocol(cursor, result)
+        return result
+
+    }
+
+    private fun getObjCProtocolAt(cursor: CValue<CXCursor>): ObjCProtocolImpl? {
+        assert(cursor.kind == CXCursorKind.CXCursor_ObjCProtocolDecl) { cursor.kind }
+        if (clang_isCursorDefinition(cursor) == 0) {
+            val definition = clang_getCursorDefinition(cursor)
+            if (clang_isCursorDefinition(cursor) == 0) return null
+            return getObjCProtocolAt(definition)
+        }
+
+        val name = clang_getCursorDisplayName(cursor).convertAndDispose()
+
+        objCProtocolsByName[name]?.let { return it }
+
+        val result = ObjCProtocolImpl(name)
+        objCProtocolsByName[name] = result
+
+        addChildrenToClassOrProtocol(cursor, result)
+        return result
+    }
+
+    private fun addChildrenToClassOrProtocol(cursor: CValue<CXCursor>, result: ObjCClassOrProtocolImpl) {
+        visitChildren(cursor) { child, _ ->
+            when (child.kind) {
+                CXCursorKind.CXCursor_ObjCSuperClassRef -> {
+                    assert(cursor.kind == CXCursorKind.CXCursor_ObjCInterfaceDecl)
+                    result as ObjCClassImpl
+
+                    assert(result.baseClass == null)
+                    result.baseClass = getObjCClassAt(clang_getCursorReferenced(child))
+                }
+                CXCursorKind.CXCursor_ObjCProtocolRef -> {
+                    getObjCProtocolAt(clang_getCursorReferenced(child))?.let {
+                        if (it !in result.protocols) {
+                            result.protocols.add(it)
+                        }
+                    }
+                }
+                CXCursorKind.CXCursor_ObjCClassMethodDecl, CXCursorKind.CXCursor_ObjCInstanceMethodDecl -> {
+                    getObjCMethod(child)?.let { method ->
+                        result.methods.removeAll { method.replaces(it) }
+                        result.methods.add(method)
+                    }
+                }
+                else -> {}
+            }
+            CXChildVisitResult.CXChildVisit_Continue
+        }
+    }
+
     fun getTypedef(type: CValue<CXType>): Type {
         val declCursor = clang_getTypeDeclaration(type)
         val name = getCursorSpelling(declCursor)
 
         val underlying = convertType(clang_getTypedefDeclUnderlyingType(declCursor))
+        if (clang_getCursorLexicalParent(declCursor).kind != CXCursorKind.CXCursor_TranslationUnit) {
+            // Objective-C type parameters are represented as non-top-level typedefs.
+            // Erase for now:
+            return underlying
+        }
+
+        if (library.language == Language.OBJECTIVE_C) {
+            if (name == "BOOL" || name == "Boolean") {
+                assert(clang_Type_getSizeOf(type) == 1L)
+                return BoolType
+            }
+
+            if (underlying is ObjCPointer && (name == "Class" || name == "id") ||
+                    underlying is PointerType && name == "SEL") {
+
+                // Ignore implicit Objective-C typedefs:
+                return underlying
+            }
+        }
+
+
 
         if ((underlying is RecordType && underlying.decl.spelling.split(' ').last() == name) ||
                 (underlying is EnumType && underlying.def.spelling.split(' ').last() == name)) {
@@ -189,10 +341,36 @@ internal class NativeIndexImpl(val library: NativeLibrary) : NativeIndex() {
         }
     }
 
-    private fun convertCursorType(cursor: CValue<CXCursor>) =
+    /**
-        convertType(clang_getCursorType(cursor))
+     * Computes [StructDef.hasUnalignedFields] property.
+     */
+    fun structHasUnalignedFields(structDefCursor: CValue<CXCursor>): Boolean {
+        var hasUnalignedFields = false
+        visitChildren(structDefCursor) { child, _ ->
+            if (clang_getCursorKind(child) == CXCursorKind.CXCursor_FieldDecl &&
+                    clang_Cursor_isBitField(child) == 0 &&
+                    clang_Cursor_getOffsetOfField(child) %
+                            (clang_Type_getAlignOf(clang_getCursorType(child)) * 8) != 0L) {
 
-    fun convertType(type: CValue<CXType>): Type {
+                hasUnalignedFields = true
+                CXChildVisitResult.CXChildVisit_Break
+            } else {
+                CXChildVisitResult.CXChildVisit_Continue
+            }
+        }
+
+        return hasUnalignedFields
+    }
+
+    private fun convertCursorType(cursor: CValue<CXCursor>) =
+        convertType(clang_getCursorType(cursor), clang_getDeclTypeAttributes(cursor))
+
+    private inline fun objCType(supplier: () -> ObjCPointer) = when (library.language) {
+        Language.C -> UnsupportedType
+        Language.OBJECTIVE_C -> supplier()
+    }
+
+    fun convertType(type: CValue<CXType>, typeAttributes: CValue<CXTypeAttributes>? = null): Type {
         val primitiveType = convertUnqualifiedPrimitiveType(type)
         if (primitiveType != UnsupportedType) {
             return primitiveType
@@ -217,7 +395,17 @@ internal class NativeIndexImpl(val library: NativeLibrary) : NativeIndex() {
 
             CXType_Void -> VoidType
 
-            CXType_Typedef -> getTypedef(type)
+            CXType_Typedef -> {
+                val declCursor = clang_getTypeDeclaration(type)
+                val declSpelling = getCursorSpelling(declCursor)
+                val underlying = convertType(clang_getTypedefDeclUnderlyingType(declCursor))
+                when {
+                    declSpelling == "instancetype" && underlying is ObjCPointer ->
+                        ObjCInstanceType(getNullability(type, typeAttributes))
+
+                    else -> getTypedef(type)
+                }
+            }
 
             CXType_Record -> RecordType(getStructDeclAt(clang_getTypeDeclaration(type)))
             CXType_Enum -> EnumType(getEnumDefAt(clang_getTypeDeclaration(type)))
@@ -245,16 +433,58 @@ internal class NativeIndexImpl(val library: NativeLibrary) : NativeIndex() {
                 convertFunctionType(type)
             }
 
+            CXType_ObjCObjectPointer -> objCType {
+                val declaration = clang_getTypeDeclaration(clang_getPointeeType(type))
+                val declarationKind = declaration.kind
+                val nullability = getNullability(type, typeAttributes)
+                when (declarationKind) {
+                    CXCursorKind.CXCursor_NoDeclFound -> ObjCIdType(nullability, getProtocols(type))
+
+                    CXCursorKind.CXCursor_ObjCInterfaceDecl ->
+                        ObjCObjectPointer(getObjCClassAt(declaration), nullability, getProtocols(type))
+
+                    else -> TODO(declarationKind.toString())
+                }
+            }
+
+            CXType_ObjCId -> objCType { ObjCIdType(getNullability(type, typeAttributes), getProtocols(type)) }
+
+            CXType_ObjCClass -> objCType { ObjCClassPointer(getNullability(type, typeAttributes), getProtocols(type)) }
+
+            CXType_ObjCSel -> PointerType(VoidType)
+
+            CXType_BlockPointer -> objCType { ObjCIdType(getNullability(type, typeAttributes), getProtocols(type)) }
+
             else -> UnsupportedType
         }
     }
 
+    private fun getNullability(
+            type: CValue<CXType>, typeAttributes: CValue<CXTypeAttributes>?
+    ): ObjCPointer.Nullability {
+
+        if (typeAttributes == null) return ObjCPointer.Nullability.Unspecified
+
+        return when (clang_Type_getNullabilityKind(type, typeAttributes)) {
+            CXNullabilityKind.CXNullabilityKind_Nullable -> ObjCPointer.Nullability.Nullable
+            CXNullabilityKind.CXNullabilityKind_NonNull -> ObjCPointer.Nullability.NonNull
+            CXNullabilityKind.CXNullabilityKind_Unspecified -> ObjCPointer.Nullability.Unspecified
+        }
+    }
+
+    private fun getProtocols(type: CValue<CXType>): List<ObjCProtocol> {
+        val num = clang_Type_getNumProtocols(type)
+        return (0 until num).mapNotNull { index ->
+            getObjCProtocolAt(clang_Type_getProtocol(type, index))
+        }
+    }
+
     private fun convertFunctionType(type: CValue<CXType>): Type {
         val kind = type.kind
         assert (kind == CXType_Unexposed || kind == CXType_FunctionProto)
 
         return if (clang_isFunctionTypeVariadic(type) != 0) {
-            UnsupportedType
+            VoidType // make this function pointer opaque.
         } else {
             val returnType = convertType(clang_getResultType(type))
             val numArgs = clang_getNumArgTypes(type)
@@ -286,38 +516,160 @@ internal class NativeIndexImpl(val library: NativeLibrary) : NativeIndex() {
             }
 
             CXIdxEntity_Function -> {
-                val name = entityName!!
+                if (isAvailable(cursor)) {
-                val returnType = convertType(clang_getCursorResultType(cursor))
+                    functionById[getDeclarationId(cursor)] = getFunction(cursor)
-                val argNum = clang_Cursor_getNumArguments(cursor)
-                val args = (0 .. argNum - 1).map {
-                    val argCursor = clang_Cursor_getArgument(cursor, it)
-                    val argName = getCursorSpelling(argCursor)
-                    val type = convertCursorType(argCursor)
-                    Parameter(argName, type)
                 }
-
-                val binaryName = when (library.language) {
-                    Language.C -> clang_Cursor_getMangling(cursor).convertAndDispose()
-                }
-
-                val definitionCursor = clang_getCursorDefinition(cursor)
-                val isDefined = (clang_Cursor_isNull(definitionCursor) == 0)
-
-                val isVararg = clang_Cursor_isVariadic(cursor) != 0
-
-                functionByName[name] = FunctionDecl(name, args, returnType, binaryName, isDefined, isVararg)
             }
 
             CXIdxEntity_Enum -> {
                 getEnumDefAt(cursor)
             }
 
+            CXIdxEntity_ObjCClass -> {
+                if (isAvailable(cursor)) {
+                    getObjCClassAt(clang_getCursorReferenced(cursor))
+                }
+            }
+
+            CXIdxEntity_ObjCCategory -> {
+                val classCursor = getObjCCategoryClassCursor(cursor)
+                if (isAvailable(classCursor)) {
+                    val objCClass = getObjCClassAt(classCursor)
+                    addChildrenToClassOrProtocol(cursor, objCClass)
+                }
+            }
+
+            CXIdxEntity_ObjCProtocol -> {
+                if (isAvailable(cursor)) {
+                    getObjCProtocolAt(cursor)
+                }
+            }
+
+            CXIdxEntity_ObjCProperty -> {
+                val container = clang_getCursorSemanticParent(cursor)
+                if (isAvailable(cursor) && isAvailable(container)) {
+                    val propertyInfo = clang_index_getObjCPropertyDeclInfo(info.ptr)!!.pointed
+                    val getter = getObjCMethod(propertyInfo.getter!!.pointed.cursor.readValue())
+                    val setter = propertyInfo.setter?.let {
+                        getObjCMethod(it.pointed.cursor.readValue())
+                    }
+
+                    if (getter != null) {
+                        val property = ObjCProperty(entityName!!, getter, setter)
+                        val classOrProtocol: ObjCClassOrProtocolImpl? = when (container.kind) {
+                            CXCursorKind.CXCursor_ObjCCategoryDecl -> {
+                                val classCursor = getObjCCategoryClassCursor(container)
+                                if (isAvailable(classCursor)) {
+                                    getObjCClassAt(classCursor)
+                                } else {
+                                    null
+                                }
+                            }
+                            CXCursorKind.CXCursor_ObjCInterfaceDecl -> getObjCClassAt(container)
+                            CXCursorKind.CXCursor_ObjCProtocolDecl -> getObjCProtocolAt(container)!!
+                            else -> error(container.kind)
+                        }
+
+                        if (classOrProtocol != null) {
+                            classOrProtocol.properties.removeAll { property.replaces(it) }
+                            classOrProtocol.properties.add(property)
+                        }
+                    }
+                }
+            }
+
             else -> {
                 // Ignore declaration.
             }
         }
     }
 
+    private fun getFunction(cursor: CValue<CXCursor>): FunctionDecl {
+        val name = clang_getCursorSpelling(cursor).convertAndDispose()
+        val returnType = convertType(clang_getCursorResultType(cursor), clang_getCursorResultTypeAttributes(cursor))
+
+        val parameters = getFunctionParameters(cursor)
+
+        val binaryName = when (library.language) {
+            Language.C, Language.OBJECTIVE_C -> clang_Cursor_getMangling(cursor).convertAndDispose()
+        }
+
+        val definitionCursor = clang_getCursorDefinition(cursor)
+        val isDefined = (clang_Cursor_isNull(definitionCursor) == 0)
+
+        val isVararg = clang_Cursor_isVariadic(cursor) != 0
+
+        return FunctionDecl(name, parameters, returnType, binaryName, isDefined, isVararg)
+    }
+
+    private fun getObjCMethod(cursor: CValue<CXCursor>): ObjCMethod? {
+        if (!isAvailable(cursor)) {
+            return null
+        }
+
+        val selector = clang_getCursorDisplayName(cursor).convertAndDispose()
+
+        // Ignore some very special methods:
+        when (selector) {
+            "dealloc", "retain", "release", "autorelease", "retainCount", "self" -> return null
+        }
+
+        val encoding = clang_getDeclObjCTypeEncoding(cursor).convertAndDispose()
+        val returnType = convertType(clang_getCursorResultType(cursor), clang_getCursorResultTypeAttributes(cursor))
+        val parameters = getFunctionParameters(cursor)
+
+        val isClass = when (cursor.kind) {
+            CXCursorKind.CXCursor_ObjCClassMethodDecl -> true
+            CXCursorKind.CXCursor_ObjCInstanceMethodDecl -> false
+            else -> error(cursor.kind)
+        }
+
+        return ObjCMethod(selector, encoding, parameters, returnType,
+                isClass = isClass,
+                nsConsumesSelf = hasAttribute(cursor, NS_CONSUMES_SELF),
+                nsReturnsRetained = hasAttribute(cursor, NS_RETURNS_RETAINED),
+                isOptional = (clang_Cursor_isObjCOptional(cursor) != 0),
+                isInit = (clang_Cursor_isObjCInitMethod(cursor) != 0))
+    }
+
+    // TODO: unavailable declarations should be imported as deprecated.
+    private fun isAvailable(cursor: CValue<CXCursor>): Boolean = when (clang_getCursorAvailability(cursor)) {
+        CXAvailabilityKind.CXAvailability_Available,
+        CXAvailabilityKind.CXAvailability_Deprecated -> true
+
+        CXAvailabilityKind.CXAvailability_NotAvailable,
+        CXAvailabilityKind.CXAvailability_NotAccessible -> false
+    }
+
+    private fun getFunctionParameters(cursor: CValue<CXCursor>): List<Parameter> {
+        val argNum = clang_Cursor_getNumArguments(cursor)
+        val args = (0..argNum - 1).map {
+            val argCursor = clang_Cursor_getArgument(cursor, it)
+            val argName = getCursorSpelling(argCursor)
+            val type = convertCursorType(argCursor)
+            Parameter(argName, type,
+                    nsConsumed = hasAttribute(argCursor, NS_CONSUMED))
+        }
+        return args
+    }
+
+    private val NS_CONSUMED = "ns_consumed"
+    private val NS_CONSUMES_SELF = "ns_consumes_self"
+    private val NS_RETURNS_RETAINED = "ns_returns_retained"
+
+    private fun hasAttribute(cursor: CValue<CXCursor>, name: String): Boolean {
+        var result = false
+        visitChildren(cursor) { child, _ ->
+            if (clang_isAttribute(child.kind) != 0 && clang_Cursor_getAttributeSpelling(child)?.toKString() == name) {
+                result = true
+                CXChildVisitResult.CXChildVisit_Break
+            } else {
+                CXChildVisitResult.CXChildVisit_Continue
+            }
+        }
+        return result
+    }
+
 }
 
 fun buildNativeIndexImpl(library: NativeLibrary): NativeIndex {

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

@@ -27,7 +27,7 @@ internal fun findMacroConstants(library: NativeLibrary, nativeIndex: NativeIndex
     val names = collectMacroConstantsNames(library)
     // TODO: apply user-defined filters.
 
-    val constants = expandMacroConstants(library, names, typeConverter = nativeIndex::convertType)
+    val constants = expandMacroConstants(library, names, typeConverter = { nativeIndex.convertType(it) })
 
     nativeIndex.macroConstants.addAll(constants)
 }
@@ -109,7 +109,7 @@ private fun reparseWithCodeSnippet(library: NativeLibrary,
         // so the code pattern should force the constant evaluation that corresponds to language rules.
         val codeSnippetLines = when (library.language) {
             // Note: __auto_type is a GNU extension which is supported by clang.
-            Language.C -> listOf(
+            Language.C, Language.OBJECTIVE_C -> listOf(
                     "const __auto_type KNI_INDEXER_VARIABLE = $name;",
                     // Clang evaluate API doesn't provide a way to get a `long long` value yet;
                     // so extract such values from the enum declaration:

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

@@ -16,8 +16,9 @@
 
 package org.jetbrains.kotlin.native.interop.indexer
 
-enum class Language {
+enum class Language(val sourceFileExtension: String) {
-    C
+    C("c"),
+    OBJECTIVE_C("m")
 }
 
 data class NativeLibrary(val includes: List<String>,
@@ -39,6 +40,8 @@ fun buildNativeIndex(library: NativeLibrary): NativeIndex = buildNativeIndexImpl
 abstract class NativeIndex {
     abstract val structs: List<StructDecl>
     abstract val enums: List<EnumDef>
+    abstract val objCClasses: List<ObjCClass>
+    abstract val objCProtocols: List<ObjCProtocol>
     abstract val typedefs: List<TypedefDef>
     abstract val functions: List<FunctionDecl>
     abstract val macroConstants: List<ConstantDef>
@@ -65,7 +68,8 @@ abstract class StructDecl(val spelling: String) {
  */
 abstract class StructDef(val size: Long, val align: Int,
                          val decl: StructDecl,
-                         val hasNaturalLayout: Boolean) {
+                         val hasNaturalLayout: Boolean,
+                         val hasUnalignedFields: Boolean) {
 
     abstract val fields: List<Field>
 }
@@ -78,15 +82,48 @@ class EnumConstant(val name: String, val value: Long, val isExplicitlyDefined: B
 /**
  * C enum definition.
  */
-abstract class EnumDef(val spelling: String, val baseType: PrimitiveType) {
+abstract class EnumDef(val spelling: String, val baseType: Type) {
 
     abstract val constants: List<EnumConstant>
 }
 
+sealed class ObjCClassOrProtocol(val name: String) {
+    abstract val protocols: List<ObjCProtocol>
+    abstract val methods: List<ObjCMethod>
+    abstract val properties: List<ObjCProperty>
+}
+
+data class ObjCMethod(
+        val selector: String, val encoding: String, val parameters: List<Parameter>, private val returnType: Type,
+        val isClass: Boolean, val nsConsumesSelf: Boolean, val nsReturnsRetained: Boolean,
+        val isOptional: Boolean, val isInit: Boolean
+) {
+
+    fun returnsInstancetype(): Boolean = returnType is ObjCInstanceType
+
+    fun getReturnType(container: ObjCClassOrProtocol): Type = if (returnType is ObjCInstanceType) {
+        when (container) {
+            is ObjCClass -> ObjCObjectPointer(container, returnType.nullability, protocols = emptyList())
+            is ObjCProtocol -> ObjCIdType(returnType.nullability, protocols = listOf(container))
+        }
+    } else {
+        returnType
+    }
+}
+
+data class ObjCProperty(val name: String, val getter: ObjCMethod, val setter: ObjCMethod?) {
+    fun getType(container: ObjCClassOrProtocol): Type = getter.getReturnType(container)
+}
+
+abstract class ObjCClass(name: String) : ObjCClassOrProtocol(name) {
+    abstract val baseClass: ObjCClass?
+}
+abstract class ObjCProtocol(name: String) : ObjCClassOrProtocol(name)
+
 /**
  * C function parameter.
  */
-class Parameter(val name: String?, val type: Type)
+class Parameter(val name: String?, val type: Type, val nsConsumed: Boolean)
 
 /**
  * C function declaration.
@@ -117,6 +154,8 @@ interface PrimitiveType : Type
 
 object CharType : PrimitiveType
 
+object BoolType : PrimitiveType
+
 data class IntegerType(val size: Int, val isSigned: Boolean, val spelling: String) : PrimitiveType
 
 // TODO: floating type is not actually defined entirely by its size.
@@ -142,4 +181,34 @@ data class IncompleteArrayType(override val elemType: Type) : ArrayType
 
 data class Typedef(val def: TypedefDef) : Type
 
+sealed class ObjCPointer : Type {
+    enum class Nullability {
+        Nullable, NonNull, Unspecified
+    }
+
+    abstract val nullability: Nullability
+}
+
+sealed class ObjCQualifiedPointer : ObjCPointer() {
+    abstract val protocols: List<ObjCProtocol>
+}
+
+data class ObjCObjectPointer(
+        val def: ObjCClass,
+        override val nullability: Nullability,
+        override val protocols: List<ObjCProtocol>
+) : ObjCQualifiedPointer()
+
+data class ObjCClassPointer(
+        override val nullability: Nullability,
+        override val protocols: List<ObjCProtocol>
+) : ObjCQualifiedPointer()
+
+data class ObjCIdType(
+        override val nullability: Nullability,
+        override val protocols: List<ObjCProtocol>
+) : ObjCQualifiedPointer()
+
+data class ObjCInstanceType(override val nullability: Nullability) : ObjCPointer()
+
 object UnsupportedType : Type

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

@@ -176,10 +176,7 @@ internal fun Appendable.appendPreamble(library: NativeLibrary) = this.apply {
  * Creates temporary source file which includes the library.
  */
 internal fun NativeLibrary.createTempSource(): File {
-    val suffix = when (language) {
+    val result = createTempFile(suffix = ".${language.sourceFileExtension}")
-        Language.C -> ".c"
-    }
-    val result = createTempFile(suffix = suffix)
     result.deleteOnExit()
 
     result.bufferedWriter().use { writer ->
@@ -479,3 +476,9 @@ internal fun getFilteredHeaders(library: NativeLibrary, index: CXIndex, translat
 
     return result
 }
+
+fun ObjCMethod.replaces(other: ObjCMethod): Boolean =
+        this.isClass == other.isClass && this.selector == other.selector
+
+fun ObjCProperty.replaces(other: ObjCProperty): Boolean =
+        this.getter.replaces(other.getter)

Interop/Runtime/src/jvm/kotlin/kotlinx/cinterop/JvmCallbacks.kt

@@ -379,22 +379,7 @@ private class Struct(val size: Long, val align: Int, elementTypes: List<CType<*>
 ) {
     override fun read(location: NativePtr) = interpretPointed<ByteVar>(location).readValue<CStructVar>(size, align)
 
-    override fun write(location: NativePtr, value: CValue<*>) {
+    override fun write(location: NativePtr, value: CValue<*>) = value.write(location)
-        // TODO: probably CValue must be redesigned.
-        val fakePlacement = object : NativePlacement {
-            var used = false
-            override fun alloc(size: Long, align: Int): NativePointed {
-                assert(!used)
-                assert (size == this@Struct.size)
-                assert (align == this@Struct.align)
-                used = true
-                return interpretPointed<ByteVar>(location)
-            }
-        }
-
-        value.getPointer(fakePlacement)
-        assert (fakePlacement.used)
-    }
 }
 
 private class CEnumType(private val rawValueCType: CType<Number>) : CType<CEnum>(rawValueCType.ffiType) {

Interop/Runtime/src/main/kotlin/kotlinx/cinterop/Types.kt

@@ -67,6 +67,25 @@ abstract class CValuesRef<T : CPointed> {
     abstract fun getPointer(placement: NativePlacement): CPointer<T>
 }
 
+inline fun <T : CPointed, R> CValuesRef<T>?.usePointer(block: (CPointer<T>?) -> R): R {
+    val allocated: Boolean
+    val pointer: CPointer<T>? = if (this is CPointer<T>?) {
+        allocated = false
+        this
+    } else {
+        allocated = true
+        this!!.getPointer(nativeHeap)
+    }
+
+    return try {
+        block(pointer)
+    } finally {
+        if (allocated) {
+            nativeHeap.free(pointer.rawValue)
+        }
+    }
+}
+
 /**
  * The (possibly empty) sequence of immutable C values.
  * It is self-contained and doesn't depend on native memory.
@@ -241,6 +260,11 @@ abstract class CEnumVar : CPrimitiveVar()
 // generics below are used for typedef support
 // these classes are not supposed to be used directly, instead the typealiases are provided.
 
+@Suppress("FINAL_UPPER_BOUND")
+class BooleanVarOf<T : Boolean>(override val rawPtr: NativePtr) : CPrimitiveVar() {
+    companion object : Type(1)
+}
+
 @Suppress("FINAL_UPPER_BOUND")
 class ByteVarOf<T : Byte>(override val rawPtr: NativePtr) : CPrimitiveVar() {
     companion object : Type(1)
@@ -271,6 +295,7 @@ class DoubleVarOf<T : Double>(override val rawPtr: NativePtr) : CPrimitiveVar()
     companion object : Type(8)
 }
 
+typealias BooleanVar = BooleanVarOf<Boolean>
 typealias ByteVar = ByteVarOf<Byte>
 typealias ShortVar = ShortVarOf<Short>
 typealias IntVar = IntVarOf<Int>
@@ -278,6 +303,20 @@ typealias LongVar = LongVarOf<Long>
 typealias FloatVar = FloatVarOf<Float>
 typealias DoubleVar = DoubleVarOf<Double>
 
+@Suppress("FINAL_UPPER_BOUND", "UNCHECKED_CAST")
+var <T : Boolean> BooleanVarOf<T>.value: T
+    get() {
+        val byte = nativeMemUtils.getByte(this)
+        return byte.toBoolean() as T
+    }
+    set(value) = nativeMemUtils.putByte(this, value.toByte())
+
+@Suppress("NOTHING_TO_INLINE")
+inline fun Boolean.toByte(): Byte = if (this) 1 else 0
+
+@Suppress("NOTHING_TO_INLINE")
+inline fun Byte.toBoolean() = (this - 0 != 0)
+
 @Suppress("FINAL_UPPER_BOUND", "UNCHECKED_CAST")
 var <T : Byte> ByteVarOf<T>.value: T
     get() = nativeMemUtils.getByte(this) as T

Interop/Runtime/src/main/kotlin/kotlinx/cinterop/Utils.kt

@@ -218,6 +218,21 @@ fun <T : CVariable> CPointed.readValue(size: Long, align: Int): CValue<T> {
 // TODO: find better name.
 inline fun <reified T : CStructVar> T.readValue(): CValue<T> = this.readValue(sizeOf<T>(), alignOf<T>())
 
+fun CValue<*>.write(location: NativePtr) {
+    // TODO: probably CValue must be redesigned.
+    val fakePlacement = object : NativePlacement {
+        var used = false
+        override fun alloc(size: Long, align: Int): NativePointed {
+            assert(!used)
+            used = true
+            return interpretPointed<ByteVar>(location)
+        }
+    }
+
+    this.getPointer(fakePlacement)
+    assert(fakePlacement.used)
+}
+
 // TODO: optimize
 fun <T : CVariable> CValues<T>.getBytes(): ByteArray = memScoped {
     val result = ByteArray(size)

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

@@ -0,0 +1,156 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+@file:Suppress("NOTHING_TO_INLINE")
+
+package kotlinx.cinterop
+
+interface ObjCObject
+interface ObjCClass : ObjCObject
+typealias ObjCObjectMeta = ObjCClass
+
+abstract class ObjCObjectBase protected constructor() : ObjCObject {
+    final override fun equals(other: Any?): Boolean = TODO()
+    final override fun hashCode(): Int = TODO()
+    final override fun toString(): String = TODO()
+}
+
+abstract class ObjCObjectBaseMeta protected constructor() : ObjCObjectBase(), ObjCObjectMeta {}
+
+external fun optional(): Nothing
+
+/**
+ * The runtime representation of any [ObjCObject].
+ */
+@ExportTypeInfo("theObjCPointerHolderTypeInfo")
+class ObjCPointerHolder(inline val rawPtr: NativePtr) {
+    init {
+        assert(rawPtr != nativeNullPtr)
+        objc_retain(rawPtr)
+    }
+
+    final override fun equals(other: Any?): Boolean = TODO()
+    final override fun hashCode(): Int = TODO()
+    final override fun toString(): String = TODO()
+}
+
+@konan.internal.Intrinsic
+@konan.internal.ExportForCompiler
+private external fun ObjCObject.initFromPtr(ptr: NativePtr)
+
+@konan.internal.ExportForCompiler
+private fun ObjCObject.initFrom(other: ObjCObject?) = this.initFromPtr(other!!.rawPtr)
+
+fun <T : Any?> Any?.uncheckedCast(): T = @Suppress("UNCHECKED_CAST") (this as T) // TODO: make private
+
+inline fun <T : ObjCObject?> interpretObjCPointerOrNull(rawPtr: NativePtr): T? = if (rawPtr != nativeNullPtr) {
+    ObjCPointerHolder(rawPtr).uncheckedCast<T>()
+} else {
+    null
+}
+
+inline fun <T : ObjCObject?> interpretObjCPointer(rawPtr: NativePtr): T? = interpretObjCPointerOrNull<T>(rawPtr)!!
+
+inline val ObjCObject.rawPtr: NativePtr get() = (this.uncheckedCast<ObjCPointerHolder>()).rawPtr
+inline val ObjCObject?.rawPtr: NativePtr get() = if (this != null) {
+    (this.uncheckedCast<ObjCPointerHolder>()).rawPtr
+} else {
+    nativeNullPtr
+}
+
+class ObjCObjectVar<T : ObjCObject?>(override val rawPtr: NativePtr) : CVariable {
+    companion object : CVariable.Type(pointerSize.toLong(), pointerSize)
+}
+
+class ObjCStringVarOf<T : String?>(override val rawPtr: NativePtr) : CVariable {
+    companion object : CVariable.Type(pointerSize.toLong(), pointerSize)
+}
+
+var <T : String?> ObjCStringVarOf<T>.value: T
+    get() = TODO()
+    set(value) = TODO()
+
+@konan.internal.Intrinsic external fun getReceiverOrSuper(receiver: NativePtr, superClass: NativePtr): COpaquePointer?
+
+@Target(AnnotationTarget.CLASS)
+@Retention(AnnotationRetention.BINARY)
+annotation class ExternalObjCClass()
+
+@Target(AnnotationTarget.FUNCTION)
+@Retention(AnnotationRetention.BINARY)
+annotation class ObjCMethod(val selector: String, val bridge: String)
+
+@Target(AnnotationTarget.FUNCTION)
+@Retention(AnnotationRetention.BINARY)
+annotation class ObjCBridge(val selector: String, val encoding: String, val imp: String)
+
+@Target(AnnotationTarget.CONSTRUCTOR)
+@Retention(AnnotationRetention.BINARY)
+annotation class ObjCConstructor(val initSelector: String)
+
+@Target(AnnotationTarget.FILE)
+@Retention(AnnotationRetention.BINARY)
+annotation class InteropStubs()
+
+@konan.internal.ExportForCompiler
+private fun <T : ObjCObject> allocObjCObject(clazz: NativePtr): T {
+    val rawResult = objc_allocWithZone(clazz)
+    if (rawResult == nativeNullPtr) {
+        throw OutOfMemoryError("Unable to allocate Objective-C object")
+    }
+
+    val result = interpretObjCPointerOrNull<T>(rawResult)!!
+    // `objc_allocWithZone` returns retained pointer. Balance it:
+    objc_release(rawResult)
+    // TODO: do not retain this pointer in `interpretObjCPointerOrNull` instead.
+
+    return result
+}
+
+@konan.internal.Intrinsic
+@konan.internal.ExportForCompiler
+private external fun <T : ObjCObject> getObjCClass(): NativePtr
+
+@konan.internal.Intrinsic external fun getMessenger(superClass: NativePtr): COpaquePointer?
+@konan.internal.Intrinsic external fun getMessengerLU(superClass: NativePtr): COpaquePointer?
+
+// Konan runtme:
+
+@SymbolName("CreateNSStringFromKString")
+external fun CreateNSStringFromKString(str: String?): NativePtr
+
+@SymbolName("CreateKStringFromNSString")
+external fun CreateKStringFromNSString(ptr: NativePtr): String?
+
+// Objective-C runtime:
+
+@SymbolName("objc_retainAutoreleaseReturnValue")
+external fun objc_retainAutoreleaseReturnValue(ptr: NativePtr): NativePtr
+
+@SymbolName("Kotlin_objc_autoreleasePoolPush")
+external fun objc_autoreleasePoolPush(): NativePtr
+
+@SymbolName("Kotlin_objc_autoreleasePoolPop")
+external fun objc_autoreleasePoolPop(ptr: NativePtr)
+
+@SymbolName("Kotlin_objc_allocWithZone")
+private external fun objc_allocWithZone(clazz: NativePtr): NativePtr
+
+@SymbolName("Kotlin_objc_retain")
+external fun objc_retain(ptr: NativePtr): NativePtr
+
+@SymbolName("Kotlin_objc_release")
+external fun objc_release(ptr: NativePtr)

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

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package kotlinx.cinterop
+
+inline fun <R> autoreleasepool(block: () -> R): R {
+    val pool = objc_autoreleasePoolPush()
+    return try {
+        block()
+    } finally {
+        objc_autoreleasePoolPop(pool)
+    }
+}
+
+// TODO: null checks
+var <T : ObjCObject?> ObjCObjectVar<T>.value: T
+    get() = interpretObjCPointerOrNull<T>(nativeMemUtils.getNativePtr(this)).uncheckedCast<T>()
+    set(value) = nativeMemUtils.putNativePtr(this, value.rawPtr)

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

@@ -66,6 +66,11 @@ private tailrec fun convertArgument(
 
     is CEnum -> convertArgument(argument.value, isVariadic, location, additionalPlacement)
 
+    is ObjCPointerHolder -> {
+        location.reinterpret<COpaquePointerVar>()[0] = interpretCPointer(argument.rawPtr)
+        FFI_TYPE_KIND_POINTER
+    }
+
     else -> throw Error("unsupported argument: $argument")
 }
 

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

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.native.interop.gen
+
+class NativeCodeBuilder {
+    val lines = mutableListOf<String>()
+
+    fun out(line: String): Unit {
+        lines.add(line)
+    }
+}
+
+inline fun buildNativeCodeLines(block: NativeCodeBuilder.() -> Unit): List<String> {
+    val builder = NativeCodeBuilder()
+    builder.block()
+    return builder.lines
+}
+
+class KotlinCodeBuilder {
+    private val lines = mutableListOf<String>()
+
+    private val freeStack = mutableListOf<String>()
+    private val nesting get() = freeStack.size
+
+    fun out(line: String) {
+        lines.add("    ".repeat(nesting) + line)
+    }
+
+    fun pushBlock(line: String, free: String = "") {
+        out(line)
+        freeStack.add(free)
+    }
+
+    private fun popBlocks() {
+        while (freeStack.isNotEmpty()) {
+            val free = freeStack.last()
+            freeStack.removeAt(freeStack.lastIndex)
+            out("} $free".trim())
+        }
+    }
+
+    fun build(): List<String> {
+        this.popBlocks()
+        val result = this.lines.toList()
+        this.lines.clear()
+        return result
+    }
+}
+
+inline fun buildKotlinCodeLines(block: KotlinCodeBuilder.() -> Unit): List<String> {
+    val builder = KotlinCodeBuilder()
+    builder.block()
+    return builder.build()
+}
+
+interface StubGenerationContext {
+    val nativeBridges: NativeBridges
+    fun addTopLevelDeclaration(lines: List<String>)
+}
+
+interface KotlinStub {
+    fun generate(context: StubGenerationContext): Sequence<String>
+}

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

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.native.interop.gen
+
+val kotlinKeywords = setOf(
+        "as", "break", "class", "continue", "do", "else", "false", "for", "fun", "if", "in",
+        "interface", "is", "null", "object", "package", "return", "super", "this", "throw",
+        "true", "try", "typealias", "val", "var", "when", "while"
+)
+
+/**
+ * The expression written in native language.
+ */
+typealias NativeExpression = String
+
+/**
+ * The expression written in Kotlin.
+ */
+typealias KotlinExpression = String
+
+/**
+ * For this identifier constructs the string to be parsed by Kotlin as `SimpleName`
+ * defined [here](https://kotlinlang.org/docs/reference/grammar.html#SimpleName).
+ */
+fun String.asSimpleName(): String = if (this in kotlinKeywords) {
+    "`$this`"
+} else {
+    this
+}
+
+/**
+ * Returns the expression to be parsed by Kotlin as string literal with given contents,
+ * i.e. transforms `foo$bar` to `"foo\$bar"`.
+ */
+fun String.quoteAsKotlinLiteral(): KotlinExpression {
+    val sb = StringBuilder()
+    sb.append('"')
+
+    this.forEach { c ->
+        val escaped = when (c) {
+            in 'a' .. 'z', in 'A' .. 'Z', in '0' .. '9', '_', '@', ':', '{', '}', '=', '[', ']', '^', '#', '*' -> c.toString()
+            '$' -> "\\$"
+            else -> "\\u" + "%04X".format(c.toInt()) // TODO: improve result readability by preserving more characters.
+        }
+        sb.append(escaped)
+    }
+
+    sb.append('"')
+    return sb.toString()
+}
+
+fun block(header: String, lines: Iterable<String>) = block(header, lines.asSequence())
+
+fun block(header: String, lines: Sequence<String>) =
+        sequenceOf("$header {") +
+                lines.map { "    $it" } +
+                sequenceOf("}")
+
+val annotationForUnableToImport
+    get() = "@Deprecated(${"Unable to import this declaration".quoteAsKotlinLiteral()}, level = DeprecationLevel.ERROR)"
+
+fun String.applyToStrings(vararg arguments: String) =
+        "${this}(${arguments.joinToString { it.quoteAsKotlinLiteral() }})"

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

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.native.interop.gen
+
+import org.jetbrains.kotlin.native.interop.indexer.Type
+
+data class TypedKotlinValue(val type: Type, val value: KotlinExpression)
+data class TypedNativeValue(val type: Type, val value: NativeExpression)
+
+/**
+ * Generates bridges between Kotlin and native, passing arbitrary native-typed values.
+ *
+ * It does the same as [SimpleBridgeGenerator] except that it supports any native types, e.g. struct values.
+ */
+interface MappingBridgeGenerator {
+    fun kotlinToNative(
+            builder: KotlinCodeBuilder,
+            nativeBacked: NativeBacked,
+            returnType: Type,
+            kotlinValues: List<TypedKotlinValue>,
+            block: NativeCodeBuilder.(nativeValues: List<NativeExpression>) -> NativeExpression
+    ): KotlinExpression
+
+    fun nativeToKotlin(
+            builder: NativeCodeBuilder,
+            nativeBacked: NativeBacked,
+            returnType: Type,
+            nativeValues: List<TypedNativeValue>,
+            block: KotlinCodeBuilder.(kotlinValues: List<KotlinExpression>) -> KotlinExpression
+    ): NativeExpression
+}

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

@@ -0,0 +1,196 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.native.interop.gen
+
+import org.jetbrains.kotlin.native.interop.indexer.RecordType
+import org.jetbrains.kotlin.native.interop.indexer.Type
+import org.jetbrains.kotlin.native.interop.indexer.VoidType
+
+/**
+ * The [MappingBridgeGenerator] implementation which uses [SimpleBridgeGenerator] as the backend and
+ * maps the type using [mirror].
+ */
+class MappingBridgeGeneratorImpl(
+        val declarationMapper: DeclarationMapper,
+        val simpleBridgeGenerator: SimpleBridgeGenerator
+) : MappingBridgeGenerator {
+
+    override fun kotlinToNative(
+            builder: KotlinCodeBuilder,
+            nativeBacked: NativeBacked,
+            returnType: Type,
+            kotlinValues: List<TypedKotlinValue>,
+            block: NativeCodeBuilder.(nativeValues: List<NativeExpression>) -> NativeExpression
+    ): KotlinExpression {
+        val bridgeArguments = mutableListOf<BridgeTypedKotlinValue>()
+
+        kotlinValues.forEachIndexed { index, (type, value) ->
+            if (type.unwrapTypedefs() is RecordType) {
+                val tmpVarName = "kni$index"
+                builder.pushBlock("$value.usePointer { $tmpVarName ->")
+                bridgeArguments.add(BridgeTypedKotlinValue(BridgedType.NATIVE_PTR, "$tmpVarName.rawValue"))
+            } else {
+                val info = mirror(declarationMapper, type).info
+                bridgeArguments.add(BridgeTypedKotlinValue(info.bridgedType, info.argToBridged(value)))
+            }
+        }
+
+        val unwrappedReturnType = returnType.unwrapTypedefs()
+        val kniRetVal = "kniRetVal"
+        val bridgeReturnType = when (unwrappedReturnType) {
+            VoidType -> BridgedType.VOID
+            is RecordType -> {
+                val mirror = mirror(declarationMapper, returnType)
+                val tmpVarName = kniRetVal
+                builder.out("val $tmpVarName = nativeHeap.alloc<${mirror.pointedTypeName}>()")
+                builder.pushBlock("try {", free = "finally { nativeHeap.free($tmpVarName) }")
+                bridgeArguments.add(BridgeTypedKotlinValue(BridgedType.NATIVE_PTR, "$tmpVarName.rawPtr"))
+                BridgedType.VOID
+            }
+            else -> {
+                val mirror = mirror(declarationMapper, returnType)
+                mirror.info.bridgedType
+            }
+        }
+
+        val callExpr = simpleBridgeGenerator.kotlinToNative(
+                nativeBacked, bridgeReturnType, bridgeArguments
+        ) { bridgeNativeValues ->
+
+            val nativeValues = mutableListOf<String>()
+            kotlinValues.forEachIndexed { index, (type, _) ->
+                val unwrappedType = type.unwrapTypedefs()
+                if (unwrappedType is RecordType) {
+                    nativeValues.add("*(${unwrappedType.decl.spelling}*)${bridgeNativeValues[index]}")
+                } else {
+                    nativeValues.add(mirror(declarationMapper, type).info.cFromBridged(bridgeNativeValues[index]))
+                }
+            }
+
+            val nativeResult = block(nativeValues)
+
+            when (unwrappedReturnType) {
+                is VoidType -> {
+                    out(nativeResult + ";")
+                    ""
+                }
+                is RecordType -> {
+                    out("*(${unwrappedReturnType.decl.spelling}*)${bridgeNativeValues.last()} = $nativeResult;")
+                    ""
+                }
+                else -> {
+                    nativeResult
+                }
+            }
+        }
+
+        val result = when (unwrappedReturnType) {
+            is VoidType -> callExpr
+            is RecordType -> {
+                builder.out(callExpr)
+                "$kniRetVal.readValue()"
+            }
+            else -> {
+                val mirror = mirror(declarationMapper, returnType)
+                mirror.info.argFromBridged(callExpr)
+            }
+        }
+
+        return result
+    }
+
+    override fun nativeToKotlin(
+            builder: NativeCodeBuilder,
+            nativeBacked: NativeBacked,
+            returnType: Type,
+            nativeValues: List<TypedNativeValue>,
+            block: KotlinCodeBuilder.(kotlinValues: List<KotlinExpression>) -> KotlinExpression
+    ): NativeExpression {
+
+        val bridgeArguments = mutableListOf<BridgeTypedNativeValue>()
+
+        nativeValues.forEachIndexed { index, (type, value) ->
+            val bridgeArgument = if (type.unwrapTypedefs() is RecordType) {
+                BridgeTypedNativeValue(BridgedType.NATIVE_PTR, "&$value")
+            } else {
+                val info = mirror(declarationMapper, type).info
+                BridgeTypedNativeValue(info.bridgedType, value)
+            }
+            bridgeArguments.add(bridgeArgument)
+        }
+
+        val unwrappedReturnType = returnType.unwrapTypedefs()
+        val kniRetVal = "kniRetVal"
+        val bridgeReturnType = when (unwrappedReturnType) {
+            VoidType -> BridgedType.VOID
+            is RecordType -> {
+                val tmpVarName = kniRetVal
+                builder.out("${unwrappedReturnType.decl.spelling} $tmpVarName;")
+                bridgeArguments.add(BridgeTypedNativeValue(BridgedType.NATIVE_PTR, "&$tmpVarName"))
+                BridgedType.VOID
+            }
+            else -> {
+                val mirror = mirror(declarationMapper, returnType)
+                mirror.info.bridgedType
+            }
+        }
+
+        val callExpr = simpleBridgeGenerator.nativeToKotlin(
+                nativeBacked,
+                bridgeReturnType,
+                bridgeArguments
+        ) { bridgeKotlinValues ->
+            val kotlinValues = mutableListOf<String>()
+            nativeValues.forEachIndexed { index, (type, _) ->
+                val mirror = mirror(declarationMapper, type)
+                if (type.unwrapTypedefs() is RecordType) {
+                    kotlinValues.add(
+                            "interpretPointed<${mirror.pointedTypeName}>(${bridgeKotlinValues[index]}).readValue()"
+                    )
+                } else {
+                    kotlinValues.add(mirror.info.argFromBridged(bridgeKotlinValues[index]))
+                }
+            }
+
+            val kotlinResult = block(kotlinValues)
+            when (unwrappedReturnType) {
+                is RecordType -> {
+                    "$kotlinResult.write(${bridgeKotlinValues.last()})"
+                }
+                is VoidType -> {
+                    kotlinResult
+                }
+                else -> {
+                    mirror(declarationMapper, returnType).info.argToBridged(kotlinResult)
+                }
+            }
+        }
+
+        val result = when (unwrappedReturnType) {
+            is VoidType -> callExpr
+            is RecordType -> {
+                builder.out("$callExpr;")
+                kniRetVal
+            }
+            else -> {
+                mirror(declarationMapper, returnType).info.cFromBridged(callExpr)
+            }
+        }
+
+        return result
+    }
+}

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

@@ -0,0 +1,334 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.native.interop.gen
+
+import org.jetbrains.kotlin.native.interop.indexer.*
+
+interface DeclarationMapper {
+    fun getKotlinNameForPointed(structDecl: StructDecl): String
+    fun isMappedToStrict(enumDef: EnumDef): Boolean
+    fun getKotlinNameForValue(enumDef: EnumDef): String
+}
+
+val PrimitiveType.kotlinType: String
+    get() = when (this) {
+        is CharType -> "Byte"
+
+        is BoolType -> "Boolean"
+
+    // TODO: C primitive types should probably be generated as type aliases for Kotlin types.
+        is IntegerType -> when (this.size) {
+            1 -> "Byte"
+            2 -> "Short"
+            4 -> "Int"
+            8 -> "Long"
+            else -> TODO(this.toString())
+        }
+
+        is FloatingType -> when (this.size) {
+            4 -> "Float"
+            8 -> "Double"
+            else -> TODO(this.toString())
+        }
+
+        else -> throw NotImplementedError()
+    }
+
+private val PrimitiveType.bridgedType: BridgedType
+    get() {
+        val kotlinType = this.kotlinType
+        return BridgedType.values().single {
+            it.kotlinType == kotlinType
+        }
+    }
+
+private val ObjCPointer.isNullable: Boolean
+    get() = this.nullability != ObjCPointer.Nullability.NonNull
+
+/**
+ * Describes the Kotlin types used to represent some C type.
+ */
+sealed class TypeMirror(val pointedTypeName: String, val info: TypeInfo) {
+    /**
+     * Type to be used in bindings for argument or return value.
+     */
+    abstract val argType: String
+
+    /**
+     * Mirror for C type to be represented in Kotlin as by-value type.
+     */
+    class ByValue(pointedTypeName: String, info: TypeInfo, val valueTypeName: String) :
+            TypeMirror(pointedTypeName, info) {
+
+        override val argType: String
+            get() = valueTypeName +
+                    if (info is TypeInfo.Pointer ||
+                            (info is TypeInfo.ObjCPointerInfo && info.type.isNullable)) "?" else ""
+    }
+
+    /**
+     * Mirror for C type to be represented in Kotlin as by-ref type.
+     */
+    class ByRef(pointedTypeName: String, info: TypeInfo) : TypeMirror(pointedTypeName, info) {
+        override val argType: String
+            get() = "CValue<$pointedTypeName>"
+    }
+}
+
+/**
+ * Describes various type conversions for [TypeMirror].
+ */
+sealed class TypeInfo {
+    /**
+     * The conversion from [TypeMirror.argType] to [bridgedType].
+     */
+    abstract fun argToBridged(name: String): String
+
+    /**
+     * The conversion from [bridgedType] to [TypeMirror.argType].
+     */
+    abstract fun argFromBridged(name: String): String
+
+    abstract val bridgedType: BridgedType
+
+    open fun cFromBridged(name: String): String = name
+
+    open fun cToBridged(name: String): String = name
+
+    /**
+     * If this info is for [TypeMirror.ByValue], then this method describes how to
+     * construct pointed-type from value type.
+     */
+    abstract fun constructPointedType(valueType: String): String
+
+    class Primitive(override val bridgedType: BridgedType, val varTypeName: String) : TypeInfo() {
+
+        override fun argToBridged(name: String) = name
+        override fun argFromBridged(name: String) = name
+
+        override fun constructPointedType(valueType: String) = "${varTypeName}Of<$valueType>"
+    }
+
+    class Boolean : TypeInfo() {
+        override fun argToBridged(name: String) = "$name.toByte()"
+
+        override fun argFromBridged(name: String) = "$name.toBoolean()"
+
+        override val bridgedType: BridgedType get() = BridgedType.BYTE
+
+        override fun cFromBridged(name: String) = "($name) ? 1 : 0"
+
+        override fun cToBridged(name: String) = "($name) ? 1 : 0"
+
+        override fun constructPointedType(valueType: String) = "BooleanVarOf<$valueType>"
+    }
+
+    class Enum(val className: String, override val bridgedType: BridgedType) : TypeInfo() {
+        override fun argToBridged(name: String) = "$name.value"
+
+        override fun argFromBridged(name: String) = "$className.byValue($name)"
+
+        override fun constructPointedType(valueType: String) = "$className.Var" // TODO: improve
+
+    }
+
+    class Pointer(val pointee: String) : TypeInfo() {
+        override fun argToBridged(name: String) = "$name.rawValue"
+
+        override fun argFromBridged(name: String) = "interpretCPointer<$pointee>($name)"
+
+        override val bridgedType: BridgedType
+            get() = BridgedType.NATIVE_PTR
+
+        override fun cFromBridged(name: String) = "(void*)$name" // Note: required for JVM
+
+        override fun constructPointedType(valueType: String) = "CPointerVarOf<$valueType>"
+    }
+
+    class ObjCPointerInfo(val typeName: String, val type: ObjCPointer) : TypeInfo() {
+        override fun argToBridged(name: String) = "$name.rawPtr"
+
+        override fun argFromBridged(name: String) = "interpretObjCPointerOrNull<$typeName>($name)" +
+                if (type.isNullable) "" else "!!"
+
+        override val bridgedType: BridgedType
+            get() = BridgedType.OBJC_POINTER
+
+        override fun constructPointedType(valueType: String) = "ObjCObjectVar<$valueType>"
+    }
+
+    class NSString(val type: ObjCPointer) : TypeInfo() {
+        override fun argToBridged(name: String) = "CreateNSStringFromKString($name)"
+
+        override fun argFromBridged(name: String) = "CreateKStringFromNSString($name)" +
+                if (type.isNullable) "" else "!!"
+
+        override val bridgedType: BridgedType
+            get() = BridgedType.OBJC_POINTER
+
+        override fun constructPointedType(valueType: String): String {
+            return "ObjCStringVarOf<$valueType>"
+        }
+    }
+
+    class ByRef(val pointed: String) : TypeInfo() {
+        override fun argToBridged(name: String) = error(pointed)
+        override fun argFromBridged(name: String) = error(pointed)
+        override val bridgedType: BridgedType get() = error(pointed)
+        override fun cFromBridged(name: String) = error(pointed)
+        override fun cToBridged(name: String) = error(pointed)
+
+        // TODO: this method must not exist
+        override fun constructPointedType(valueType: String): String = error(pointed)
+    }
+}
+
+fun mirrorPrimitiveType(type: PrimitiveType): TypeMirror.ByValue {
+    val varTypeName = when (type) {
+        is CharType -> "ByteVar"
+        is BoolType -> "BooleanVar"
+        is IntegerType -> when (type.size) {
+            1 -> "ByteVar"
+            2 -> "ShortVar"
+            4 -> "IntVar"
+            8 -> "LongVar"
+            else -> TODO(type.toString())
+        }
+        is FloatingType -> when (type.size) {
+            4 -> "FloatVar"
+            8 -> "DoubleVar"
+            else -> TODO(type.toString())
+        }
+        else -> TODO(type.toString())
+    }
+
+    val info = if (type == BoolType) {
+        TypeInfo.Boolean()
+    } else {
+        TypeInfo.Primitive(type.bridgedType, varTypeName)
+    }
+    return TypeMirror.ByValue(varTypeName, info, type.kotlinType)
+}
+
+private fun byRefTypeMirror(pointedTypeName: String) : TypeMirror.ByRef {
+    val info = TypeInfo.ByRef(pointedTypeName)
+    return TypeMirror.ByRef(pointedTypeName, info)
+}
+
+fun mirror(declarationMapper: DeclarationMapper, type: Type): TypeMirror = when (type) {
+    is PrimitiveType -> mirrorPrimitiveType(type)
+
+    is RecordType -> byRefTypeMirror(declarationMapper.getKotlinNameForPointed(type.decl).asSimpleName())
+
+    is EnumType -> {
+        val kotlinName = declarationMapper.getKotlinNameForValue(type.def)
+
+        when {
+            declarationMapper.isMappedToStrict(type.def) -> {
+                val classSimpleName = kotlinName.asSimpleName()
+                val bridgedType = (type.def.baseType.unwrapTypedefs() as PrimitiveType).bridgedType
+                val info = TypeInfo.Enum(classSimpleName, bridgedType)
+                TypeMirror.ByValue("$classSimpleName.Var", info, classSimpleName)
+            }
+            !type.def.isAnonymous -> {
+                val baseTypeMirror = mirror(declarationMapper, type.def.baseType)
+                TypeMirror.ByValue("${kotlinName}Var", baseTypeMirror.info, kotlinName.asSimpleName())
+            }
+            else -> mirror(declarationMapper, type.def.baseType)
+        }
+    }
+
+    is PointerType -> {
+        val pointeeType = type.pointeeType
+        val unwrappedPointeeType = pointeeType.unwrapTypedefs()
+        if (unwrappedPointeeType is VoidType) {
+            val info = TypeInfo.Pointer("COpaque")
+            TypeMirror.ByValue("COpaquePointerVar", info, "COpaquePointer")
+        } else if (unwrappedPointeeType is ArrayType) {
+            mirror(declarationMapper, pointeeType)
+        } else {
+            val pointeeMirror = mirror(declarationMapper, pointeeType)
+            val info = TypeInfo.Pointer(pointeeMirror.pointedTypeName)
+            TypeMirror.ByValue("CPointerVar<${pointeeMirror.pointedTypeName}>", info,
+                    "CPointer<${pointeeMirror.pointedTypeName}>")
+        }
+    }
+
+    is ArrayType -> {
+        // TODO: array type doesn't exactly correspond neither to pointer nor to value.
+        val elemTypeMirror = mirror(declarationMapper, type.elemType)
+        if (type.elemType.unwrapTypedefs() is ArrayType) {
+            elemTypeMirror
+        } else {
+            val info = TypeInfo.Pointer(elemTypeMirror.pointedTypeName)
+            TypeMirror.ByValue("CArrayPointerVar<${elemTypeMirror.pointedTypeName}>", info,
+                    "CArrayPointer<${elemTypeMirror.pointedTypeName}>")
+        }
+    }
+
+    is FunctionType -> byRefTypeMirror("CFunction<${getKotlinFunctionType(declarationMapper, type)}>")
+
+    is Typedef -> {
+        val baseType = mirror(declarationMapper, type.def.aliased)
+        val name = type.def.name
+        when (baseType) {
+            is TypeMirror.ByValue -> TypeMirror.ByValue("${name}Var", baseType.info, name.asSimpleName())
+            is TypeMirror.ByRef -> TypeMirror.ByRef(name.asSimpleName(), baseType.info)
+        }
+
+    }
+
+    is ObjCPointer -> objCPointerMirror(type)
+
+    else -> TODO(type.toString())
+}
+
+private fun objCPointerMirror(type: ObjCPointer): TypeMirror.ByValue {
+    if (type is ObjCObjectPointer && type.def.name == "NSString") {
+        val info = TypeInfo.NSString(type)
+        val valueType = if (type.isNullable) "String?" else "String"
+        return TypeMirror.ByValue(info.constructPointedType(valueType), info, valueType)
+    }
+
+    val typeName = when (type) {
+        is ObjCIdType -> type.protocols.firstOrNull()?.kotlinName ?: "ObjCObject"
+        is ObjCClassPointer -> "ObjCClass"
+        is ObjCObjectPointer -> type.def.name
+        is ObjCInstanceType -> TODO(type.toString()) // Must have already been handled.
+    }
+
+    return objCPointerMirror(typeName.asSimpleName(), type)
+}
+
+private fun objCPointerMirror(typeName: String, type: ObjCPointer): TypeMirror.ByValue {
+    val valueType = if (type.isNullable) "$typeName?" else typeName
+    return TypeMirror.ByValue("ObjCObjectVar<$valueType>",
+            TypeInfo.ObjCPointerInfo(typeName, type), typeName)
+}
+
+fun getKotlinFunctionType(declarationMapper: DeclarationMapper, type: FunctionType): String {
+    val returnType = if (type.returnType.unwrapTypedefs() is VoidType) {
+        "Unit"
+    } else {
+        mirror(declarationMapper, type.returnType).argType
+    }
+    return "(" +
+            type.parameterTypes.map { mirror(declarationMapper, it).argType }.joinToString(", ") +
+            ") -> " +
+            returnType
+}
+

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

@@ -0,0 +1,498 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.native.interop.gen
+
+import org.jetbrains.kotlin.native.interop.gen.jvm.StubGenerator
+import org.jetbrains.kotlin.native.interop.indexer.*
+
+private fun ObjCMethod.getKotlinParameterNames(): List<String> {
+    val selectorParts = this.selector.split(":")
+
+    val result = mutableListOf<String>()
+
+    // The names of all parameters except first must depend only on the selector:
+    this.parameters.forEachIndexed { index, parameter ->
+        if (index > 0) {
+            var name = selectorParts[index]
+            if (name.isEmpty()) {
+                name = "_$index"
+            }
+
+            while (name in result) {
+                name = "_$name"
+            }
+
+            result.add(name)
+        }
+    }
+
+    this.parameters.firstOrNull()?.let {
+        var name = it.name ?: ""
+        if (name.isEmpty()) {
+            name = "arg"
+        }
+        while (name in result) {
+            name = "_$name"
+        }
+        result.add(0, name)
+    }
+
+    return result
+}
+
+class ObjCMethodStub(stubGenerator: StubGenerator,
+                     val method: ObjCMethod,
+                     private val container: ObjCClassOrProtocol) : KotlinStub, NativeBacked {
+
+    override fun generate(context: StubGenerationContext): Sequence<String> =
+            if (context.nativeBridges.isSupported(this)) {
+                val result = mutableListOf<String>()
+                result.add("@ObjCMethod".applyToStrings(method.selector, bridgeName))
+                result.add(header)
+
+                if (method.isInit && container is ObjCClass) {
+                    result.add("")
+                    result.add("@ObjCConstructor".applyToStrings(method.selector))
+                    result.add("constructor($joinedKotlinParameters) {}")
+                }
+
+                context.addTopLevelDeclaration(
+                        listOf("@konan.internal.ExportForCompiler",
+                                "@ObjCBridge".applyToStrings(method.selector, method.encoding, implementationTemplate))
+                                + block(bridgeHeader, bodyLines)
+                )
+
+                result.asSequence()
+            } else {
+                sequenceOf(
+                        annotationForUnableToImport,
+                        header
+                )
+            }
+
+    private val bodyLines: List<String>
+    private val joinedKotlinParameters: String
+    private val header: String
+    private val implementationTemplate: String
+    private val bridgeName: String
+    private val bridgeHeader: String
+
+    private val isOverride = method.isOverride(container)
+
+    init {
+        val bodyGenerator = KotlinCodeBuilder()
+
+        val kotlinParameters = mutableListOf<Pair<String, String>>()
+        val kotlinObjCBridgeParameters = mutableListOf<Pair<String, String>>()
+        val nativeBridgeArguments = mutableListOf<TypedKotlinValue>()
+
+        val kniReceiverParameter = "kniR"
+        val kniSuperClassParameter = "kniSC"
+
+        val voidPtr = PointerType(VoidType)
+
+        val returnType = method.getReturnType(container)
+
+        val messengerGetter = if (returnType.isLargeOrUnaligned()) "getMessengerLU" else "getMessenger"
+
+        kotlinObjCBridgeParameters.add(kniSuperClassParameter to "NativePtr")
+        nativeBridgeArguments.add(TypedKotlinValue(voidPtr, "$messengerGetter($kniSuperClassParameter)"))
+
+        if (method.nsConsumesSelf) {
+            // TODO: do this later due to possible exceptions
+            bodyGenerator.out("objc_retain($kniReceiverParameter.rawPtr)")
+        }
+
+        kotlinObjCBridgeParameters.add(kniReceiverParameter to "ObjCObject")
+        nativeBridgeArguments.add(
+                TypedKotlinValue(voidPtr,
+                        "getReceiverOrSuper($kniReceiverParameter.rawPtr, $kniSuperClassParameter)"))
+
+        val kotlinParameterNames = method.getKotlinParameterNames()
+
+        method.parameters.forEachIndexed { index, it ->
+            val name = kotlinParameterNames[index]
+
+            val kotlinType = stubGenerator.mirror(it.type).argType
+            kotlinParameters.add(name to kotlinType)
+
+            kotlinObjCBridgeParameters.add(name to kotlinType)
+            nativeBridgeArguments.add(TypedKotlinValue(it.type, name.asSimpleName()))
+        }
+
+        val kotlinReturnType = if (returnType.unwrapTypedefs() is VoidType) {
+            "Unit"
+        } else {
+            stubGenerator.mirror(returnType).argType
+        }
+
+        val result = stubGenerator.mappingBridgeGenerator.kotlinToNative(
+                bodyGenerator,
+                this@ObjCMethodStub,
+                returnType,
+                nativeBridgeArguments
+        ) { nativeValues ->
+            val selector = "@selector(${method.selector})"
+            val messengerParameterTypes = mutableListOf<String>()
+            messengerParameterTypes.add("void*")
+            messengerParameterTypes.add("SEL")
+            method.parameters.forEach {
+                messengerParameterTypes.add(it.getTypeStringRepresentation())
+            }
+
+            val messengerReturnType = returnType.getStringRepresentation()
+
+            val messengerType =
+                    "$messengerReturnType (* ${method.cAttributes}) (${messengerParameterTypes.joinToString()})"
+
+            val messenger = "(($messengerType) ${nativeValues.first()})"
+
+            val messengerArguments = listOf(nativeValues[1]) + selector + nativeValues.drop(2)
+
+            "$messenger(${messengerArguments.joinToString()})"
+        }
+        bodyGenerator.out("return $result")
+
+        this.implementationTemplate = genImplementationTemplate(stubGenerator)
+        this.bodyLines = bodyGenerator.build()
+
+        bridgeName = "objcKniBridge${stubGenerator.nextUniqueId()}"
+
+        this.bridgeHeader = "internal fun $bridgeName(" +
+                "${kotlinObjCBridgeParameters.joinToString { "${it.first.asSimpleName()}: ${it.second}" }})" +
+                ": $kotlinReturnType"
+
+        this.joinedKotlinParameters = kotlinParameters.joinToString { "${it.first.asSimpleName()}: ${it.second}" }
+
+        this.header = buildString {
+            if (container is ObjCClass) append("external ")
+            if (isOverride) {
+                append("override ")
+            } else if (container is ObjCClass) {
+                append("open ")
+            }
+
+            append("fun ${method.kotlinName.asSimpleName()}($joinedKotlinParameters): $kotlinReturnType")
+
+            if (container is ObjCProtocol && method.isOptional) append(" = optional()")
+        }
+    }
+
+    private fun genImplementationTemplate(stubGenerator: StubGenerator): String {
+        val codeBuilder = NativeCodeBuilder()
+
+        val result = codeBuilder.genMethodImp(stubGenerator, this, method, container)
+        stubGenerator.simpleBridgeGenerator.insertNativeBridge(this, emptyList(), codeBuilder.lines)
+
+        return result
+    }
+}
+
+private fun Type.isLargeOrUnaligned(): Boolean {
+    val unwrappedType = this.unwrapTypedefs()
+    return when (unwrappedType) {
+        is RecordType -> unwrappedType.decl.def!!.size > 16 || this.hasUnalignedMembers()
+        else -> false
+    }
+}
+
+private fun Type.hasUnalignedMembers(): Boolean = when (this) {
+    is Typedef -> this.def.aliased.hasUnalignedMembers()
+    is RecordType -> this.decl.def!!.let { def ->
+        def.hasUnalignedFields || // Check members of fields too:
+                def.fields.any { it.type.hasUnalignedMembers() }
+    }
+    is ArrayType -> this.elemType.hasUnalignedMembers()
+    else -> false
+
+// TODO: should the recursive checks be made in indexer when computing `hasUnalignedFields`?
+}
+
+private val ObjCMethod.kotlinName: String get() = selector.split(":").first()
+
+private val ObjCClassOrProtocol.protocolsWithSupers: Sequence<ObjCProtocol>
+    get() = this.protocols.asSequence().flatMap { sequenceOf(it) + it.protocolsWithSupers }
+
+private val ObjCClassOrProtocol.immediateSuperTypes: Sequence<ObjCClassOrProtocol>
+    get() {
+        val baseClass = (this as? ObjCClass)?.baseClass
+        if (baseClass != null) {
+            return sequenceOf(baseClass) + this.protocols.asSequence()
+        }
+
+        return this.protocols.asSequence()
+    }
+
+private val ObjCClassOrProtocol.selfAndSuperTypes: Sequence<ObjCClassOrProtocol>
+    get() = sequenceOf(this) + this.superTypes
+
+private val ObjCClassOrProtocol.superTypes: Sequence<ObjCClassOrProtocol>
+    get() = this.immediateSuperTypes.flatMap { it.selfAndSuperTypes }.distinct()
+
+private fun ObjCClassOrProtocol.declaredMethods(isClass: Boolean): Sequence<ObjCMethod> =
+        this.methods.asSequence().filter { it.isClass == isClass }
+
+private fun ObjCClassOrProtocol.inheritedMethods(isClass: Boolean): Sequence<ObjCMethod> =
+        this.superTypes.flatMap { it.declaredMethods(isClass) }.distinctBy { it.selector }
+
+private fun ObjCClassOrProtocol.methodsWithInherited(isClass: Boolean): Sequence<ObjCMethod> =
+        this.selfAndSuperTypes.flatMap { it.declaredMethods(isClass) }.distinctBy { it.selector }
+
+private fun ObjCMethod.isOverride(container: ObjCClassOrProtocol): Boolean =
+        container.superTypes.any { superType -> superType.methods.any(this::replaces) }
+
+abstract class ObjCContainerStub(stubGenerator: StubGenerator,
+                                 private val container: ObjCClassOrProtocol,
+                                 private val isMeta: Boolean) : KotlinStub {
+
+    private val methods: List<ObjCMethod>
+
+    init {
+        val superMethods = container.inheritedMethods(isMeta)
+
+        // Add all methods declared in the class or protocol:
+        var methods = container.declaredMethods(isMeta)
+
+        // Exclude those which are identically declared in super types:
+        methods -= superMethods
+
+        // Add some special methods from super types:
+        methods += superMethods.filter { it.returnsInstancetype() || it.isInit }
+
+        // Add methods from adopted protocols that must be implemented according to Kotlin rules:
+        if (container is ObjCClass) {
+            methods += container.protocolsWithSupers.flatMap { it.declaredMethods(isMeta) }.filter { !it.isOptional }
+        }
+
+        // Add methods inherited from multiple supertypes that must be defined according to Kotlin rules:
+        methods += container.immediateSuperTypes
+                .flatMap { superType ->
+                    val methodsWithInherited = superType.methodsWithInherited(isMeta)
+                    // Select only those which are represented as non-abstract in Kotlin:
+                    when (superType) {
+                        is ObjCClass -> methodsWithInherited
+                        is ObjCProtocol -> methodsWithInherited.filter { it.isOptional }
+                    }
+                }
+                .groupBy { it.selector }
+                .mapNotNull { (_, inheritedMethods) -> if (inheritedMethods.size > 1) inheritedMethods.first() else null }
+
+        this.methods = methods.distinctBy { it.selector }.toList()
+    }
+
+    private val methodStubs = methods.map {
+        ObjCMethodStub(stubGenerator, it, container)
+    }
+
+    private val properties: List<ObjCProperty>
+
+    init {
+        val superProperties = container.superTypes.flatMap { it.properties.asSequence() }
+
+        this.properties = container.properties.filter {
+            it.getter.isClass == isMeta &&
+                    // Select only properties that don't override anything:
+                    superProperties.none(it::replaces)
+        }
+    }
+
+    val propertyStubs = properties.map {
+        ObjCPropertyStub(stubGenerator, it, container)
+    }
+
+    private val classHeader: String
+
+    init {
+        val nameSuffix = if (isMeta) "Meta" else ""
+
+        val supers = mutableListOf<String>()
+
+        if (container is ObjCClass) {
+            supers.add(container.baseClassName)
+        }
+        container.protocols.forEach {
+            supers.add(it.kotlinName)
+        }
+
+        if (supers.isEmpty()) {
+            assert(container is ObjCProtocol)
+            supers.add("ObjCObject")
+        }
+
+        val keywords = when (container) {
+            is ObjCClass -> "open class"
+            is ObjCProtocol -> "interface"
+        }
+
+        val supersString = supers.joinToString { "$it$nameSuffix".asSimpleName() }
+        val name = "${container.kotlinName}$nameSuffix".asSimpleName()
+        this.classHeader = "@ExternalObjCClass $keywords $name : $supersString"
+    }
+
+    open fun generateBody(context: StubGenerationContext): Sequence<String> {
+        var result = (propertyStubs.asSequence() + methodStubs.asSequence())
+                .flatMap { sequenceOf("") + it.generate(context) }
+
+        if (container is ObjCClass && methodStubs.none {
+            it.method.isInit && it.method.parameters.isEmpty() && context.nativeBridges.isSupported(it)
+        }) {
+            // Always generate default constructor.
+            // If it is not produced for an init method, then include it manually:
+            result += sequenceOf("", "protected constructor() {}")
+        }
+
+        return result
+    }
+
+    override fun generate(context: StubGenerationContext): Sequence<String> = block(classHeader, generateBody(context))
+}
+
+open class ObjCClassOrProtocolStub(
+        stubGenerator: StubGenerator,
+        private val container: ObjCClassOrProtocol
+) : ObjCContainerStub(
+        stubGenerator,
+        container,
+        isMeta = false
+) {
+    private val metaClassStub =
+            object : ObjCContainerStub(stubGenerator, container, isMeta = true) {}
+
+    override fun generate(context: StubGenerationContext) =
+            metaClassStub.generate(context) + "" + super.generate(context)
+}
+
+class ObjCProtocolStub(stubGenerator: StubGenerator, protocol: ObjCProtocol) :
+        ObjCClassOrProtocolStub(stubGenerator, protocol)
+
+class ObjCClassStub(stubGenerator: StubGenerator, private val clazz: ObjCClass) :
+        ObjCClassOrProtocolStub(stubGenerator, clazz) {
+
+    override fun generateBody(context: StubGenerationContext) =
+            sequenceOf( "companion object : ${clazz.kotlinName}Meta() {}") +
+                    super.generateBody(context)
+}
+
+class ObjCPropertyStub(
+        val stubGenerator: StubGenerator, val property: ObjCProperty, val clazz: ObjCClassOrProtocol
+) : KotlinStub {
+
+    override fun generate(context: StubGenerationContext): Sequence<String> {
+        val type = property.getType(clazz)
+
+        val kotlinType = stubGenerator.mirror(type).argType
+
+        val kind = if (property.setter == null) "val" else "var"
+        val modifiers = if (clazz is ObjCClass) "" else "final "
+        val result = mutableListOf(
+                "$modifiers$kind ${property.name.asSimpleName()}: $kotlinType",
+                "    get() = ${property.getter.kotlinName.asSimpleName()}()"
+        )
+
+        property.setter?.let {
+            result.add("    set(value) = ${it.kotlinName.asSimpleName()}(value)")
+        }
+
+        return result.asSequence()
+    }
+
+}
+
+val ObjCClassOrProtocol.kotlinName: String get() = when (this) {
+    is ObjCClass -> this.name
+    is ObjCProtocol -> "${this.name}Protocol"
+}
+
+private val ObjCClass.baseClassName: String
+    get() = baseClass?.name ?: "ObjCObject"
+
+private fun Parameter.getTypeStringRepresentation() =
+        (if (this.nsConsumed) "__attribute__((ns_consumed)) " else "") + type.getStringRepresentation()
+
+private fun ObjCMethod.getSelfTypeStringRepresentation() = if (this.nsConsumesSelf) {
+    "__attribute__((ns_consumed)) id"
+} else {
+    "id"
+}
+
+val ObjCMethod.cAttributes get() = if (this.nsReturnsRetained) {
+    "__attribute__((ns_returns_retained)) "
+} else {
+    ""
+}
+
+private fun NativeCodeBuilder.genMethodImp(
+        stubGenerator: StubGenerator,
+        nativeBacked: NativeBacked,
+        method: ObjCMethod,
+        container: ObjCClassOrProtocol
+): String {
+
+    val returnType = method.getReturnType(container)
+    val cReturnType = returnType.getStringRepresentation()
+
+    val bridgeArguments = mutableListOf<TypedNativeValue>()
+
+    val parameters = mutableListOf<Pair<String, String>>()
+
+    parameters.add("self" to method.getSelfTypeStringRepresentation())
+
+    val receiverType = ObjCIdType(ObjCPointer.Nullability.NonNull, protocols = emptyList())
+    bridgeArguments.add(TypedNativeValue(receiverType, "self"))
+
+    parameters.add("_cmd" to "SEL")
+
+    method.parameters.forEachIndexed { index, parameter ->
+        val name = "p$index"
+        parameters.add(name to parameter.getTypeStringRepresentation())
+        bridgeArguments.add(TypedNativeValue(parameter.type, name))
+    }
+
+    val functionName = "knimi_" + stubGenerator.pkgName.replace('.', '_') + stubGenerator.nextUniqueId()
+    val functionAttr = method.cAttributes
+
+    out("$cReturnType $functionName(${parameters.joinToString { it.second + " " + it.first }}) $functionAttr{")
+
+    val callExpr = stubGenerator.mappingBridgeGenerator.nativeToKotlin(
+            this,
+            nativeBacked,
+            returnType,
+            bridgeArguments
+    ) { kotlinValues ->
+
+        val kotlinReceiverType = if (method.isClass) "${container.kotlinName}Meta" else container.kotlinName
+        val kotlinRawReceiver = kotlinValues.first()
+        val kotlinReceiver = "$kotlinRawReceiver.uncheckedCast<${kotlinReceiverType.asSimpleName()}>()"
+
+        val namedArguments = kotlinValues.drop(1).zip(method.getKotlinParameterNames()) { value, name ->
+            "${name.asSimpleName()} = $value"
+        }
+
+        "${kotlinReceiver}.${method.kotlinName.asSimpleName()}(${namedArguments.joinToString()})"
+    }
+
+    if (returnType.unwrapTypedefs() is VoidType) {
+        out("    $callExpr;")
+    } else {
+        out("    return $callExpr;")
+    }
+
+    out("}")
+
+    return functionName
+}
+

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

@@ -0,0 +1,93 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.native.interop.gen
+
+/**
+ * The type which has exact counterparts on both Kotlin and native side and can be directly passed through bridges.
+ */
+enum class BridgedType(val kotlinType: String) {
+    BYTE("Byte"),
+    SHORT("Short"),
+    INT("Int"),
+    LONG("Long"),
+    FLOAT("Float"),
+    DOUBLE("Double"),
+    NATIVE_PTR("NativePtr"),
+    OBJC_POINTER("NativePtr"),
+    VOID("Unit")
+}
+
+data class BridgeTypedKotlinValue(val type: BridgedType, val value: KotlinExpression)
+data class BridgeTypedNativeValue(val type: BridgedType, val value: NativeExpression)
+
+/**
+ * The entity which depends on native bridges.
+ */
+interface NativeBacked
+
+/**
+ * Generates simple bridges between Kotlin and native, passing [BridgedType] values.
+ */
+interface SimpleBridgeGenerator {
+
+    /**
+     * Generates the expression to convert given Kotlin values to native counterparts, pass through the bridge,
+     * use inside the native code produced by [block] and then return the result back.
+     *
+     * @param block produces native code lines into the builder and returns the expression to be used as the result.
+     */
+    fun kotlinToNative(
+            nativeBacked: NativeBacked,
+            returnType: BridgedType,
+            kotlinValues: List<BridgeTypedKotlinValue>,
+            block: NativeCodeBuilder.(nativeValues: List<NativeExpression>) -> NativeExpression
+    ): KotlinExpression
+
+    /**
+     * Generates the expression to convert given native values to Kotlin counterparts, pass through the bridge,
+     * use inside the Kotlin code produced by [block] and then return the result back.
+     */
+    fun nativeToKotlin(
+            nativeBacked: NativeBacked,
+            returnType: BridgedType,
+            nativeValues: List<BridgeTypedNativeValue>,
+            block: KotlinCodeBuilder.(kotlinValues: List<KotlinExpression>) -> KotlinExpression
+    ): NativeExpression
+
+    fun insertNativeBridge(
+            nativeBacked: NativeBacked,
+            kotlinLines: List<String>,
+            nativeLines: List<String>
+    )
+
+    /**
+     * Prepares all requested native bridges.
+     */
+    fun prepare(): NativeBridges
+}
+
+interface NativeBridges {
+    /**
+     * @return `true` iff given entity is supported by these bridges,
+     * i.e. all bridges it depends on can be successfully generated.
+     */
+    fun isSupported(nativeBacked: NativeBacked): Boolean
+
+    val kotlinLines: Sequence<String>
+    val nativeLines: Sequence<String>
+}
+

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

@@ -0,0 +1,219 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.native.interop.gen
+
+import org.jetbrains.kotlin.native.interop.gen.jvm.KotlinPlatform
+import org.jetbrains.kotlin.native.interop.indexer.NativeLibrary
+import org.jetbrains.kotlin.native.interop.indexer.mapFragmentIsCompilable
+
+class SimpleBridgeGeneratorImpl(
+        private val platform: KotlinPlatform,
+        private val pkgName: String,
+        private val jvmFileClassName: String,
+        private val libraryForCStubs: NativeLibrary
+) : SimpleBridgeGenerator {
+
+    private var nextUniqueId = 0
+
+    private val BridgedType.nativeType: String get() = when (platform) {
+        KotlinPlatform.JVM -> when (this) {
+            BridgedType.BYTE -> "jbyte"
+            BridgedType.SHORT -> "jshort"
+            BridgedType.INT -> "jint"
+            BridgedType.LONG -> "jlong"
+            BridgedType.FLOAT -> "jfloat"
+            BridgedType.DOUBLE -> "jdouble"
+            BridgedType.NATIVE_PTR -> "jlong"
+            BridgedType.OBJC_POINTER -> TODO()
+            BridgedType.VOID -> "void"
+        }
+        KotlinPlatform.NATIVE -> when (this) {
+            BridgedType.BYTE -> "int8_t"
+            BridgedType.SHORT -> "int16_t"
+            BridgedType.INT -> "int32_t"
+            BridgedType.LONG -> "int64_t"
+            BridgedType.FLOAT -> "float"
+            BridgedType.DOUBLE -> "double"
+            BridgedType.NATIVE_PTR -> "void*"
+            BridgedType.OBJC_POINTER -> "id"
+            BridgedType.VOID -> "void"
+        }
+    }
+
+    private inner class NativeBridge(val kotlinLines: List<String>, val nativeLines: List<String>)
+
+    override fun kotlinToNative(
+            nativeBacked: NativeBacked,
+            returnType: BridgedType,
+            kotlinValues: List<BridgeTypedKotlinValue>,
+            block: NativeCodeBuilder.(arguments: List<NativeExpression>) -> NativeExpression
+    ): KotlinExpression {
+
+        val kotlinLines = mutableListOf<String>()
+        val nativeLines = mutableListOf<String>()
+
+        val kotlinFunctionName = "kniBridge${nextUniqueId++}"
+        val kotlinParameters = kotlinValues.withIndex().joinToString {
+            "p${it.index}: ${it.value.type.kotlinType}"
+        }
+
+        val callExpr = "$kotlinFunctionName(${kotlinValues.joinToString { it.value }})"
+
+        val cFunctionParameters = when (platform) {
+            KotlinPlatform.JVM -> mutableListOf(
+                    "jniEnv" to "JNIEnv*",
+                    "jclss" to "jclass"
+            )
+            KotlinPlatform.NATIVE -> mutableListOf()
+        }
+
+        kotlinValues.withIndex().mapTo(cFunctionParameters) {
+            "p${it.index}" to it.value.type.nativeType
+        }
+
+        val joinedCParameters = cFunctionParameters.joinToString { (name, type) -> "$type $name" }
+        val cReturnType = returnType.nativeType
+
+        val cFunctionHeader = when (platform) {
+            KotlinPlatform.JVM -> {
+                val funcFullName = buildString {
+                    if (pkgName.isNotEmpty()) {
+                        append(pkgName)
+                        append('.')
+                    }
+                    append(jvmFileClassName)
+                    append('.')
+                    append(kotlinFunctionName)
+                }
+
+                val functionName = "Java_" + funcFullName.replace("_", "_1").replace('.', '_').replace("$", "_00024")
+                "JNIEXPORT $cReturnType JNICALL $functionName ($joinedCParameters)"
+            }
+            KotlinPlatform.NATIVE -> {
+                val functionName = pkgName.replace('.', '_') + "_$kotlinFunctionName"
+                kotlinLines.add("@SymbolName(${functionName.quoteAsKotlinLiteral()})")
+                "$cReturnType $functionName ($joinedCParameters)"
+            }
+        }
+        nativeLines.add(cFunctionHeader + " {")
+
+        buildNativeCodeLines {
+            val cExpr = block(cFunctionParameters.takeLast(kotlinValues.size).map { (name, _) -> name })
+            if (returnType != BridgedType.VOID) {
+                out("return ($cReturnType)$cExpr;")
+            }
+        }.forEach {
+            nativeLines.add("    $it")
+        }
+
+        nativeLines.add("}")
+        kotlinLines.add("private external fun $kotlinFunctionName($kotlinParameters): ${returnType.kotlinType}")
+
+        val nativeBridge = NativeBridge(kotlinLines, nativeLines)
+        nativeBridges.add(nativeBacked to nativeBridge)
+
+        return callExpr
+    }
+
+    override fun nativeToKotlin(
+            nativeBacked: NativeBacked,
+            returnType: BridgedType,
+            nativeValues: List<BridgeTypedNativeValue>,
+            block: KotlinCodeBuilder.(arguments: List<KotlinExpression>) -> KotlinExpression
+    ): NativeExpression {
+
+        if (platform != KotlinPlatform.NATIVE) TODO()
+
+        val kotlinLines = mutableListOf<String>()
+        val nativeLines = mutableListOf<String>()
+
+        val kotlinFunctionName = "kniBridge${nextUniqueId++}"
+        val kotlinParameters = nativeValues.withIndex().map {
+            "p${it.index}" to it.value.type.kotlinType
+        }
+        val joinedKotlinParameters = kotlinParameters.joinToString { "${it.first}: ${it.second}" }
+
+        val cFunctionParameters = nativeValues.withIndex().map {
+            "p${it.index}" to it.value.type.nativeType
+        }
+        val joinedCParameters = cFunctionParameters.joinToString { (name, type) -> "$type $name" }
+        val cReturnType = returnType.nativeType
+
+        val symbolName = pkgName.replace('.', '_') + "_$kotlinFunctionName"
+        kotlinLines.add("@konan.internal.ExportForCppRuntime(${symbolName.quoteAsKotlinLiteral()})")
+        val cFunctionHeader = "$cReturnType $symbolName($joinedCParameters)"
+
+        nativeLines.add("$cFunctionHeader;")
+        kotlinLines.add("private fun $kotlinFunctionName($joinedKotlinParameters): ${returnType.kotlinType} {")
+
+        buildKotlinCodeLines {
+            var kotlinExpr = block(kotlinParameters.map { (name, _) -> name })
+            if (returnType == BridgedType.OBJC_POINTER) {
+                // The Kotlin code may lose the ownership on this pointer after returning from the bridge,
+                // so retain the pointer and autorelease it:
+                kotlinExpr = "objc_retainAutoreleaseReturnValue($kotlinExpr)"
+                // (Objective-C does the same for returned pointers).
+            }
+            out("return $kotlinExpr")
+        }.forEach {
+            kotlinLines.add("    $it")
+        }
+
+        kotlinLines.add("}")
+
+        insertNativeBridge(nativeBacked, kotlinLines, nativeLines)
+
+        return "$symbolName(${nativeValues.joinToString { it.value }})"
+
+    }
+
+    override fun insertNativeBridge(nativeBacked: NativeBacked, kotlinLines: List<String>, nativeLines: List<String>) {
+        val nativeBridge = NativeBridge(kotlinLines, nativeLines)
+        nativeBridges.add(nativeBacked to nativeBridge)
+    }
+
+    private val nativeBridges = mutableListOf<Pair<NativeBacked, NativeBridge>>()
+
+    override fun prepare(): NativeBridges {
+        val includedBridges = mutableListOf<NativeBridge>()
+        val excludedClients = mutableSetOf<NativeBacked>()
+
+        nativeBridges.map { it.second.nativeLines }
+                .mapFragmentIsCompilable(libraryForCStubs)
+                .forEachIndexed { index, isCompilable ->
+                    if (isCompilable) {
+                        includedBridges.add(nativeBridges[index].second)
+                    } else {
+                        excludedClients.add(nativeBridges[index].first)
+                    }
+                }
+
+        // TODO: exclude unused bridges.
+
+        return object : NativeBridges {
+
+            override val kotlinLines: Sequence<String>
+                get() = includedBridges.asSequence().flatMap { it.kotlinLines.asSequence() }
+
+            override val nativeLines: Sequence<String>
+                get() = includedBridges.asSequence().flatMap { it.nativeLines.asSequence() }
+
+            override fun isSupported(nativeBacked: NativeBacked): Boolean =
+                    nativeBacked !in excludedClients
+        }
+    }
+}

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

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.native.interop.gen
+
+import org.jetbrains.kotlin.native.interop.indexer.*
+
+val EnumDef.isAnonymous: Boolean
+    get() = spelling.contains("(anonymous ") // TODO: it is a hack
+
+/**
+ * Returns the expression which could be used for this type in C code.
+ * Note: the resulting string doesn't exactly represent this type, but it is enough for current purposes.
+ *
+ * TODO: use libclang to implement?
+ */
+fun Type.getStringRepresentation(): String = when (this) {
+    is VoidType -> "void"
+    is CharType -> "char"
+    is BoolType -> "BOOL"
+    is IntegerType -> this.spelling
+    is FloatingType -> this.spelling
+
+    is PointerType, is ArrayType -> "void*"
+
+    is RecordType -> this.decl.spelling
+
+    is EnumType -> if (this.def.isAnonymous) {
+        this.def.baseType.getStringRepresentation()
+    } else {
+        this.def.spelling
+    }
+
+    is Typedef -> this.def.aliased.getStringRepresentation()
+
+    is ObjCPointer -> when (this) {
+        is ObjCIdType -> "id$protocolQualifier"
+        is ObjCClassPointer -> "Class$protocolQualifier"
+        is ObjCObjectPointer -> "${def.name}$protocolQualifier*"
+        is ObjCInstanceType -> TODO(this.toString()) // Must have already been handled.
+    }
+
+    else -> throw kotlin.NotImplementedError()
+}
+
+private val ObjCQualifiedPointer.protocolQualifier: String
+    get() = if (this.protocols.isEmpty()) "" else " <${protocols.joinToString { it.name }}>"
+
+tailrec fun Type.unwrapTypedefs(): Type = if (this is Typedef) {
+    this.def.aliased.unwrapTypedefs()
+} else {
+    this
+}

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

@@ -324,6 +324,19 @@ private fun downloadDependencies(dependenciesRoot: String, target: String, konan
     maybeExecuteHelper(dependenciesRoot, konanProperties, dependencyList)
 }
 
+private fun selectNativeLanguage(config: Properties): Language {
+    val languages = mapOf(
+            "C" to Language.C,
+            "Objective-C" to Language.OBJECTIVE_C
+    )
+
+    val language = config.getProperty("language") ?: return Language.C
+
+    return languages[language] ?:
+            error("Unexpected language '$language'. Possible values are: ${languages.keys.joinToString { "'$it'" }}")
+}
+
+
 private fun processLib(konanHome: String,
                        substitutions: Map<String, String>,
                        args: Map<String, List<String>>) {
@@ -363,9 +376,24 @@ private fun processLib(konanHome: String,
 
     val defaultOpts = konanProperties.defaultCompilerOpts(target, dependencies)
     val headerFiles = config.getSpaceSeparated("headers") + additionalHeaders
-    val compilerOpts = config.getSpaceSeparated("compilerOpts") + defaultOpts + additionalCompilerOpts
+    val language = selectNativeLanguage(config)
+    val compilerOpts: List<String> = mutableListOf<String>().apply {
+        addAll(config.getSpaceSeparated("compilerOpts"))
+        addAll(defaultOpts)
+        addAll(additionalCompilerOpts)
+        addAll(when (language) {
+            Language.C -> emptyList()
+            Language.OBJECTIVE_C -> {
+                // "Objective-C" within interop means "Objective-C with ARC":
+                listOf("-fobjc-arc")
+                // Using this flag here has two effects:
+                // 1. The headers are parsed with ARC enabled, thus the API is visible correctly.
+                // 2. The generated Objective-C stubs are compiled with ARC enabled, so reference counting
+                // calls are inserted automatically.
+            }
+        })
+    }
     val compiler = "clang"
-    val language = Language.C
     val excludeSystemLibs = config.getProperty("excludeSystemLibs")?.toBoolean() ?: false
     val excludeDependentModules = config.getProperty("excludeDependentModules")?.toBoolean() ?: false
 
@@ -422,7 +450,7 @@ private fun processLib(konanHome: String,
     outKtFile.parentFile.mkdirs()
 
     File(nativeLibsDir).mkdirs()
-    val outCFile = File("$nativeLibsDir/$libName.c") // TODO: select the better location.
+    val outCFile = File("$nativeLibsDir/$libName.${language.sourceFileExtension}") // TODO: select the better location.
 
     outKtFile.bufferedWriter().use { ktFile ->
         outCFile.bufferedWriter().use { cFile ->

backend.native/build.gradle

@@ -61,6 +61,7 @@ sourceSets {
           srcDir 'compiler/ir/backend.native/src/'
           srcDir "${rootProject.projectDir}/shared/src/main/kotlin"
       }
+      resources.srcDir 'compiler/ir/backend.native/resources/'
     }
     cli_bc {
       java.srcDir 'cli.bc/src'
@@ -213,7 +214,8 @@ task jars(type: Jar) {
     from 'build/classes/cli_bc', 
          'build/classes/compiler', 
          'build/classes/hashInteropStubs', 
-         'build/classes/llvmInteropStubs'
+         'build/classes/llvmInteropStubs',
+         'build/resources/compiler'
 
     dependsOn 'build', ':runtime:hostRuntime', 'external_jars'
 }

backend.native/compiler/ir/backend.native/resources/META-INF/services/org.jetbrains.kotlin.resolve.ExternalOverridabilityCondition

@@ -0,0 +1 @@
+org.jetbrains.kotlin.backend.konan.ObjCOverridabilityCondition

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

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.backend.konan
 
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.descriptors.PropertyDescriptor
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
@@ -100,6 +101,31 @@ internal class InteropBuiltIns(builtIns: KonanBuiltIns) {
     val signExtend = packageScope.getContributedFunctions("signExtend").single()
 
     val narrow = packageScope.getContributedFunctions("narrow").single()
+
+    val objCObject = packageScope.getContributedClassifier("ObjCObject") as ClassDescriptor
+    val objCPointerHolder = packageScope.getContributedClassifier("ObjCPointerHolder") as ClassDescriptor
+
+    val objCPointerHolderValue = objCPointerHolder.unsubstitutedMemberScope
+            .getContributedDescriptors().filterIsInstance<PropertyDescriptor>().single()
+
+    val objCObjectInitFromPtr = packageScope.getContributedFunctions("initFromPtr").single()
+    val objCObjectInitFrom = packageScope.getContributedFunctions("initFrom").single()
+
+    val allocObjCObject = packageScope.getContributedFunctions("allocObjCObject").single()
+
+    val getObjCClass = packageScope.getContributedFunctions("getObjCClass").single()
+
+    val objCObjectRawPtr = packageScope.getContributedVariables("rawPtr").single {
+        val extensionReceiverType = it.extensionReceiverParameter?.type
+        extensionReceiverType != null && !extensionReceiverType.isMarkedNullable &&
+                TypeUtils.getClassDescriptor(extensionReceiverType) == objCObject
+    }
+
+    val getObjCReceiverOrSuper = packageScope.getContributedFunctions("getReceiverOrSuper").single()
+
+    val getObjCMessenger = packageScope.getContributedFunctions("getMessenger").single()
+    val getObjCMessengerLU = packageScope.getContributedFunctions("getMessengerLU").single()
+
 }
 
 private fun MemberScope.getContributedVariables(name: String) =

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

@@ -0,0 +1,156 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.backend.konan
+
+import org.jetbrains.kotlin.backend.konan.descriptors.getStringValue
+import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.incremental.components.NoLookupLocation
+import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.resolve.ExternalOverridabilityCondition
+import org.jetbrains.kotlin.resolve.descriptorUtil.*
+
+private val interopPackageName = InteropBuiltIns.FqNames.packageName
+private val objCObjectFqName = interopPackageName.child(Name.identifier("ObjCObject"))
+private val objCClassFqName = interopPackageName.child(Name.identifier("ObjCClass"))
+private val externalObjCClassFqName = interopPackageName.child(Name.identifier("ExternalObjCClass"))
+private val objCMethodFqName = interopPackageName.child(Name.identifier("ObjCMethod"))
+private val objCBridgeFqName = interopPackageName.child(Name.identifier("ObjCBridge"))
+
+fun ClassDescriptor.isObjCClass(): Boolean =
+        this.getAllSuperClassifiers().any { it.fqNameSafe == objCObjectFqName } &&
+                this.containingDeclaration.fqNameSafe != interopPackageName
+
+fun ClassDescriptor.isExternalObjCClass(): Boolean = this.isObjCClass() &&
+        this.parentsWithSelf.filterIsInstance<ClassDescriptor>().any {
+            it.annotations.findAnnotation(externalObjCClassFqName) != null
+        }
+
+fun ClassDescriptor.isObjCMetaClass(): Boolean = this.getAllSuperClassifiers().any {
+    it.fqNameSafe == objCClassFqName
+}
+
+fun FunctionDescriptor.isObjCClassMethod() =
+        this.containingDeclaration.let { it is ClassDescriptor && it.isObjCClass() }
+
+fun FunctionDescriptor.isExternalObjCClassMethod() =
+        this.containingDeclaration.let { it is ClassDescriptor && it.isExternalObjCClass() }
+
+// Special case: methods from Kotlin Objective-C classes can be called virtually from bridges.
+fun FunctionDescriptor.canObjCClassMethodBeCalledVirtually(overriddenDescriptor: FunctionDescriptor) =
+        overriddenDescriptor.isOverridable && this.kind.isReal && !this.isExternalObjCClassMethod()
+
+fun ClassDescriptor.isKotlinObjCClass(): Boolean = this.isObjCClass() && !this.isExternalObjCClass()
+
+data class ObjCMethodInfo(val descriptor: FunctionDescriptor,
+                          val bridge: FunctionDescriptor,
+                          val selector: String,
+                          val encoding: String,
+                          val imp: String)
+
+private fun CallableDescriptor.getBridgeAnnotation() =
+        this.annotations.findAnnotation(objCBridgeFqName)
+
+private fun FunctionDescriptor.decodeObjCMethodAnnotation(): ObjCMethodInfo? {
+    assert (this.kind.isReal)
+
+    val methodAnnotation = this.annotations.findAnnotation(objCMethodFqName) ?: return null
+    val packageFragment = this.parents.filterIsInstance<PackageFragmentDescriptor>().single()
+
+    val bridgeName = methodAnnotation.getStringValue("bridge")
+
+    val bridge = packageFragment.getMemberScope()
+            .getContributedFunctions(Name.identifier(bridgeName), NoLookupLocation.FROM_BACKEND)
+            .single()
+
+    val bridgeAnnotation = bridge.getBridgeAnnotation()!!
+    return ObjCMethodInfo(
+            descriptor = this,
+            bridge = bridge,
+            selector = methodAnnotation.getStringValue("selector"),
+            encoding = bridgeAnnotation.getStringValue("encoding"),
+            imp = bridgeAnnotation.getStringValue("imp")
+    )
+}
+
+/**
+ * @param onlyExternal indicates whether to accept overriding methods from Kotlin classes
+ */
+private fun FunctionDescriptor.getObjCMethodInfo(onlyExternal: Boolean): ObjCMethodInfo? {
+    if (this.kind.isReal) {
+        this.decodeObjCMethodAnnotation()?.let { return it }
+
+        if (onlyExternal) {
+            return null
+        }
+    }
+
+    return this.overriddenDescriptors.asSequence().mapNotNull { it.getObjCMethodInfo(onlyExternal) }.firstOrNull()
+}
+
+fun FunctionDescriptor.getExternalObjCMethodInfo(): ObjCMethodInfo? = this.getObjCMethodInfo(onlyExternal = true)
+
+fun FunctionDescriptor.getObjCMethodInfo(): ObjCMethodInfo? = this.getObjCMethodInfo(onlyExternal = false)
+
+/**
+ * Describes method overriding rules for Objective-C methods.
+ *
+ * This class is applied at [org.jetbrains.kotlin.resolve.OverridingUtil] as configured with
+ * `META-INF/services/org.jetbrains.kotlin.resolve.ExternalOverridabilityCondition` resource.
+ */
+class ObjCOverridabilityCondition : ExternalOverridabilityCondition {
+
+    override fun getContract() = ExternalOverridabilityCondition.Contract.BOTH
+
+    override fun isOverridable(
+            superDescriptor: CallableDescriptor,
+            subDescriptor: CallableDescriptor,
+            subClassDescriptor: ClassDescriptor?
+    ): ExternalOverridabilityCondition.Result {
+
+        assert(superDescriptor.name == subDescriptor.name)
+
+        val superClass = superDescriptor.containingDeclaration as? ClassDescriptor
+        if (superClass == null || !superClass.isObjCClass()) {
+            return ExternalOverridabilityCondition.Result.UNKNOWN
+        }
+
+        return if (areSelectorsEqual(superDescriptor, subDescriptor)) {
+            ExternalOverridabilityCondition.Result.OVERRIDABLE
+        } else {
+            ExternalOverridabilityCondition.Result.INCOMPATIBLE
+        }
+
+    }
+
+    private fun areSelectorsEqual(first: CallableDescriptor, second: CallableDescriptor): Boolean {
+        // The original Objective-C method selector is represented as
+        // function name and parameter names (except first).
+
+        if (first.valueParameters.size != second.valueParameters.size) {
+            return false
+        }
+
+        first.valueParameters.forEachIndexed { index, parameter ->
+            if (index > 0 && parameter.name != second.valueParameters[index].name) {
+                return false
+            }
+        }
+
+        return true
+    }
+
+}

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

@@ -16,7 +16,7 @@
 
 package org.jetbrains.kotlin.backend.konan.descriptors
 
-import org.jetbrains.kotlin.backend.konan.Context
+import org.jetbrains.kotlin.backend.konan.*
 import org.jetbrains.kotlin.backend.konan.llvm.functionName
 import org.jetbrains.kotlin.backend.konan.llvm.localHash
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
@@ -35,9 +35,15 @@ internal class OverriddenFunctionDescriptor(val descriptor: FunctionDescriptor,
         get() = descriptor.target.bridgeDirectionsTo(overriddenDescriptor)
 
     val canBeCalledVirtually: Boolean
+        get() {
+            if (overriddenDescriptor.isObjCClassMethod()) {
+                return descriptor.canObjCClassMethodBeCalledVirtually(this.overriddenDescriptor)
+            }
+
             // We check that either method is open, or one of declarations it overrides is open.
-        get() = overriddenDescriptor.isOverridable
+            return (overriddenDescriptor.isOverridable
-                || DescriptorUtils.getAllOverriddenDeclarations(overriddenDescriptor).any { it.isOverridable }
+                    || DescriptorUtils.getAllOverriddenDeclarations(overriddenDescriptor).any { it.isOverridable })
+        }
 
     val inheritsBridge: Boolean
         get() = !descriptor.kind.isReal

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

@@ -28,6 +28,7 @@ import org.jetbrains.kotlin.builtins.getFunctionalClassKind
 import org.jetbrains.kotlin.builtins.isFunctionType
 import org.jetbrains.kotlin.builtins.isSuspendFunctionType
 import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.descriptors.annotations.AnnotationDescriptor
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
@@ -308,3 +309,9 @@ internal val FunctionDescriptor.needsInlining: Boolean
 internal val FunctionDescriptor.needsSerializedIr: Boolean 
     get() = (this.needsInlining && this.isExported())
 
+fun AnnotationDescriptor.getStringValue(name: String): String {
+    val constantValue = this.allValueArguments.entries.single {
+        it.key.asString() == name
+    }.value
+    return constantValue.value as String
+}

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

@@ -49,6 +49,18 @@ internal class KonanSymbols(context: Context, val symbolTable: SymbolTable): Sym
 
     val interopCPointerGetRawValue = symbolTable.referenceSimpleFunction(context.interopBuiltIns.cPointerGetRawValue)
 
+    val interopAllocObjCObject = symbolTable.referenceSimpleFunction(context.interopBuiltIns.allocObjCObject)
+
+    val interopGetObjCClass = symbolTable.referenceSimpleFunction(context.interopBuiltIns.getObjCClass)
+
+    val interopObjCObjectInitFromPtr =
+            symbolTable.referenceSimpleFunction(context.interopBuiltIns.objCObjectInitFromPtr)
+
+    val interopObjCObjectInitFrom = symbolTable.referenceSimpleFunction(context.interopBuiltIns.objCObjectInitFrom)
+
+    val interopObjCObjectRawValueGetter =
+            symbolTable.referenceSimpleFunction(context.interopBuiltIns.objCObjectRawPtr.getter!!)
+
     val getNativeNullPtr = symbolTable.referenceSimpleFunction(context.builtIns.getNativeNullPtr)
 
     val boxFunctions = ValueType.values().associate {

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

@@ -18,7 +18,10 @@ package org.jetbrains.kotlin.backend.konan.llvm
 
 import llvm.LLVMTypeRef
 import org.jetbrains.kotlin.backend.common.descriptors.allParameters
+import org.jetbrains.kotlin.backend.konan.descriptors.isAbstract
 import org.jetbrains.kotlin.backend.konan.descriptors.isUnit
+import org.jetbrains.kotlin.backend.konan.getObjCMethodInfo
+import org.jetbrains.kotlin.backend.konan.isExternalObjCClass
 import org.jetbrains.kotlin.backend.konan.isValueType
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.descriptors.*
@@ -148,8 +151,14 @@ private val FunctionDescriptor.signature: String
 
 // TODO: rename to indicate that it has signature included
 internal val FunctionDescriptor.functionName: String
-    get() = with(this.original) { // basic support for generics
+    get() {
-        "$name$signature"
+        with(this.original) { // basic support for generics
+            this.getObjCMethodInfo()?.let {
+                return "objc:${it.selector}"
+            }
+
+            return "$name$signature"
+        }
     }
 
 internal val FunctionDescriptor.symbolName: String
@@ -228,3 +237,6 @@ internal val ClassDescriptor.objectInstanceFieldSymbolName: String
 
         return "kobjref:$fqNameSafe"
     }
+
+internal val ClassDescriptor.typeInfoHasVtableAttached: Boolean
+    get() = !this.isAbstract() && !this.isExternalObjCClass()

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

@@ -376,6 +376,33 @@ internal class FunctionGenerationContext(val function: LLVMValueRef,
         return LLVMBuildLandingPad(builder, landingpadType, personalityFunction, numClauses, name)!!
     }
 
+    inline fun ifThenElse(
+            condition: LLVMValueRef,
+            thenValue: LLVMValueRef,
+            elseBlock: () -> LLVMValueRef
+    ): LLVMValueRef {
+        val resultType = thenValue.type
+
+        val bbExit = basicBlock(locationInfo = position())
+        val resultPhi = appendingTo(bbExit) {
+            phi(resultType)
+        }
+
+        val bbElse = basicBlock(locationInfo = position())
+
+        condBr(condition, bbExit, bbElse)
+        assignPhis(resultPhi to thenValue)
+
+        appendingTo(bbElse) {
+            val elseValue = elseBlock()
+            br(bbExit)
+            assignPhis(resultPhi to elseValue)
+        }
+
+        positionAtEnd(bbExit)
+        return resultPhi
+    }
+
     internal fun debugLocation(locationInfo: LocationInfo): DILocationRef? {
         if (!context.shouldContainDebugInfo()) return null
         update(currentBlock, locationInfo)

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

@@ -326,6 +326,9 @@ internal class Llvm(val context: Context, val llvmModule: LLVMModuleRef) {
     val throwExceptionFunction = importRtFunction("ThrowException")
     val appendToInitalizersTail = importRtFunction("AppendToInitializersTail")
 
+    val createKotlinObjCClass by lazy { importRtFunction("CreateKotlinObjCClass") }
+    val getObjCKotlinTypeInfo by lazy { importRtFunction("GetObjCKotlinTypeInfo") }
+
     private val personalityFunctionName = when (context.config.targetManager.target) {
         KonanTarget.MINGW -> "__gxx_personality_seh0"
         else -> "__gxx_personality_v0"

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

@@ -39,6 +39,7 @@ import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
 import org.jetbrains.kotlin.ir.visitors.acceptChildrenVoid
 import org.jetbrains.kotlin.ir.visitors.acceptVoid
 import org.jetbrains.kotlin.konan.target.CompilerOutputKind
+import org.jetbrains.kotlin.konan.target.KonanTarget
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
@@ -156,6 +157,8 @@ internal fun verifyModule(llvmModule: LLVMModuleRef, current: String = "") {
 internal class RTTIGeneratorVisitor(context: Context) : IrElementVisitorVoid {
     val generator = RTTIGenerator(context)
 
+    val kotlinObjCClassInfoGenerator = KotlinObjCClassInfoGenerator(context)
+
     override fun visitElement(element: IrElement) {
         element.acceptChildrenVoid(this)
     }
@@ -163,12 +166,17 @@ internal class RTTIGeneratorVisitor(context: Context) : IrElementVisitorVoid {
     override fun visitClass(declaration: IrClass) {
         super.visitClass(declaration)
 
-        if (declaration.descriptor.isIntrinsic) {
+        val descriptor = declaration.descriptor
+        if (descriptor.isIntrinsic) {
             // do not generate any code for intrinsic classes as they require special handling
             return
         }
 
-        generator.generate(declaration.descriptor)
+        generator.generate(descriptor)
+
+        if (descriptor.isKotlinObjCClass()) {
+            kotlinObjCClassInfoGenerator.generate(descriptor)
+        }
     }
 
 }
@@ -734,7 +742,7 @@ internal class CodeGeneratorVisitor(val context: Context, val lifetimes: Map<IrE
         functionGenerationContext.condBr(condition, bbExit, bbInit)
 
         functionGenerationContext.positionAtEnd(bbInit)
-        val typeInfo = codegen.typeInfoValue(value.descriptor)
+        val typeInfo = typeInfoForAllocation(value.descriptor)
         val initFunction = value.descriptor.constructors.first { it.valueParameters.size == 0 }
         val ctor = codegen.llvmFunction(initFunction)
         val args = listOf(objectPtr, typeInfo, ctor)
@@ -1350,13 +1358,32 @@ internal class CodeGeneratorVisitor(val context: Context, val lifetimes: Map<IrE
     private fun fieldPtrOfClass(thisPtr: LLVMValueRef, value: PropertyDescriptor): LLVMValueRef {
         val fieldInfo = context.llvmDeclarations.forField(value)
 
+        val classDescriptor = value.containingDeclaration as ClassDescriptor
         val typePtr = pointerType(fieldInfo.classBodyType)
-        val objectPtr = LLVMBuildGEP(functionGenerationContext.builder, thisPtr, cValuesOf(kImmOne), 1, "")
+
-        val typedObjPtr = functionGenerationContext.bitcast(typePtr, objectPtr!!)
+        val bodyPtr = getObjectBodyPtr(classDescriptor, thisPtr)
-        val fieldPtr = LLVMBuildStructGEP(functionGenerationContext.builder, typedObjPtr, fieldInfo.index, "")
+
+        val typedBodyPtr = functionGenerationContext.bitcast(typePtr, bodyPtr)
+        val fieldPtr = LLVMBuildStructGEP(functionGenerationContext.builder, typedBodyPtr, fieldInfo.index, "")
         return fieldPtr!!
     }
 
+    private fun getObjectBodyPtr(classDescriptor: ClassDescriptor, objectPtr: LLVMValueRef): LLVMValueRef {
+        return if (classDescriptor.isObjCClass()) {
+            assert(classDescriptor.isKotlinObjCClass())
+
+            val objCPtr = callDirect(context.interopBuiltIns.objCPointerHolderValue.getter!!,
+                    listOf(objectPtr), Lifetime.IRRELEVANT)
+
+            val objCDeclarations = context.llvmDeclarations.forClass(classDescriptor).objCDeclarations!!
+            val bodyOffset = functionGenerationContext.load(objCDeclarations.bodyOffsetGlobal.llvmGlobal)
+
+            functionGenerationContext.gep(objCPtr, bodyOffset)
+        } else {
+            LLVMBuildGEP(functionGenerationContext.builder, objectPtr, cValuesOf(kImmOne), 1, "")!!
+        }
+    }
+
     //-------------------------------------------------------------------------//
 
     private fun evaluateConst(value: IrConst<*>): LLVMValueRef {
@@ -1871,7 +1898,7 @@ internal class CodeGeneratorVisitor(val context: Context, val lifetimes: Map<IrE
                 functionGenerationContext.allocArray(codegen.typeInfoValue(constructedClass), count = kImmZero,
                         lifetime = resultLifetime(callee))
             } else {
-                functionGenerationContext.allocInstance(codegen.typeInfoValue(constructedClass), resultLifetime(callee))
+                functionGenerationContext.allocInstance(typeInfoForAllocation(constructedClass), resultLifetime(callee))
             }
             evaluateSimpleFunctionCall(callee.descriptor,
                     listOf(thisValue) + args, Lifetime.IRRELEVANT /* constructor doesn't return anything */)
@@ -1879,6 +1906,15 @@ internal class CodeGeneratorVisitor(val context: Context, val lifetimes: Map<IrE
         }
     }
 
+    private fun typeInfoForAllocation(constructedClass: ClassDescriptor): LLVMValueRef {
+        val descriptorForTypeInfo = if (constructedClass.isObjCClass()) {
+            context.interopBuiltIns.objCPointerHolder
+        } else {
+            constructedClass
+        }
+        return codegen.typeInfoValue(descriptorForTypeInfo)
+    }
+
     //-------------------------------------------------------------------------//
 
     private fun evaluateIntrinsicCall(callee: IrCall, args: List<LLVMValueRef>): LLVMValueRef {
@@ -1934,10 +1970,122 @@ internal class CodeGeneratorVisitor(val context: Context, val lifetimes: Map<IrE
                     LLVMBuildSExt(functionGenerationContext.builder, intPtrValue, resultType, "")!!
                 }
             }
+            interop.objCObjectInitFromPtr -> {
+                genObjCObjectInitFromPtr(args)
+            }
+
+            interop.getObjCReceiverOrSuper -> {
+                genGetObjCReceiverOrSuper(args)
+            }
+
+            interop.getObjCClass -> {
+                val typeArgument = callee.getTypeArgument(descriptor.typeParameters.single())
+                val classDescriptor = TypeUtils.getClassDescriptor(typeArgument!!)!!
+                genGetObjCClass(classDescriptor)
+            }
+
+            interop.getObjCMessenger -> {
+                genGetObjCMessenger(args, isLU = false)
+            }
+            interop.getObjCMessengerLU -> {
+                genGetObjCMessenger(args, isLU = true)
+            }
+
             else -> TODO(callee.descriptor.original.toString())
         }
     }
 
+    private fun genGetObjCClass(classDescriptor: ClassDescriptor): LLVMValueRef {
+        assert(!classDescriptor.isInterface)
+
+        return if (classDescriptor.isExternalObjCClass()) {
+            val lookUpFunction = context.llvm.externalFunction("objc_lookUpClass",
+                    functionType(int8TypePtr, false, int8TypePtr))
+
+            call(lookUpFunction,
+                    listOf(codegen.staticData.cStringLiteral(classDescriptor.name.asString()).llvm))
+        } else {
+            val objCDeclarations = context.llvmDeclarations.forClass(classDescriptor).objCDeclarations!!
+            val classPointerGlobal = objCDeclarations.classPointerGlobal.llvmGlobal
+            val gen = functionGenerationContext
+
+            val storedClass = gen.load(classPointerGlobal)
+
+            val storedClassIsNotNull = gen.icmpNe(storedClass, kNullInt8Ptr)
+
+            return gen.ifThenElse(storedClassIsNotNull, storedClass) {
+                val newClass = call(context.llvm.createKotlinObjCClass,
+                        listOf(objCDeclarations.classInfoGlobal.llvmGlobal))
+
+                gen.store(newClass, classPointerGlobal)
+                newClass
+            }
+        }
+
+    }
+
+    private fun genGetObjCMessenger(args: List<LLVMValueRef>, isLU: Boolean): LLVMValueRef {
+        val gen = functionGenerationContext
+
+        // 'LU' means "large or unaligned".
+
+        // objc_msgSend*_stret functions must be used when return value is returned through memory
+        // pointed by implicit argument, which is passed on the register that would otherwise be used for receiver.
+        // On aarch64 it is never the case, since such implicit argument gets passed on x8.
+        // On x86_64 it is the case if the return value takes more than 16 bytes or is the structure with
+        // unaligned fields (there are some complicated exceptions currently ignored). The latter condition
+        // is "encoded" by stub generator by emitting either `getMessenger` or `getMessengerLU` intrinsic call.
+        val isStret = when (context.config.targetManager.target) {
+            KonanTarget.MACBOOK, KonanTarget.IPHONE_SIM -> isLU // x86_64
+            KonanTarget.IPHONE -> false // aarch64
+            else -> TODO()
+        }
+
+        val messengerNameSuffix = if (isStret) "_stret" else ""
+
+        val functionType = functionType(int8TypePtr, true, int8TypePtr, int8TypePtr)
+
+        val normalMessenger = context.llvm.externalFunction("objc_msgSend$messengerNameSuffix", functionType)
+        val superMessenger = context.llvm.externalFunction("objc_msgSendSuper$messengerNameSuffix", functionType)
+
+        val superClass = args.single()
+        val messenger = LLVMBuildSelect(gen.builder,
+                If = gen.icmpEq(superClass, kNullInt8Ptr),
+                Then = normalMessenger,
+                Else = superMessenger,
+                Name = ""
+        )!!
+
+        return gen.bitcast(int8TypePtr, messenger)
+    }
+
+    private fun genObjCObjectInitFromPtr(args: List<LLVMValueRef>): LLVMValueRef {
+        return callDirect(context.interopBuiltIns.objCPointerHolder.unsubstitutedPrimaryConstructor!!,
+                args, Lifetime.IRRELEVANT)
+    }
+
+    private fun genGetObjCReceiverOrSuper(args: List<LLVMValueRef>): LLVMValueRef {
+        val gen = functionGenerationContext
+
+        assert(args.size == 2)
+        val receiver = args[0]
+        val superClass = args[1]
+
+        val superClassIsNull = gen.icmpEq(superClass, kNullInt8Ptr)
+
+        return gen.ifThenElse(superClassIsNull, receiver) {
+            val structType = structType(kInt8Ptr, kInt8Ptr)
+            val ptr = gen.alloca(structType)
+            gen.store(receiver,
+                    LLVMBuildGEP(gen.builder, ptr, cValuesOf(kImmZero, kImmZero), 2, "")!!)
+
+            gen.store(superClass,
+                    LLVMBuildGEP(gen.builder, ptr, cValuesOf(kImmZero, kImmOne), 2, "")!!)
+
+            gen.bitcast(int8TypePtr, ptr)
+        }
+    }
+
     //-------------------------------------------------------------------------//
     private val kImmZero     = LLVMConstInt(LLVMInt32Type(),  0, 1)!!
     private val kImmOne      = LLVMConstInt(LLVMInt32Type(),  1, 1)!!
@@ -2008,11 +2156,16 @@ internal class CodeGeneratorVisitor(val context: Context, val lifetimes: Map<IrE
     fun callVirtual(descriptor: FunctionDescriptor, args: List<LLVMValueRef>,
                     resultLifetime: Lifetime): LLVMValueRef {
         assert(LLVMTypeOf(args[0]) == codegen.kObjHeaderPtr)
-        val typeInfoPtrPtr  = LLVMBuildStructGEP(functionGenerationContext.builder, args[0], 0 /* type_info */, "")!!
-        val typeInfoPtr     = functionGenerationContext.load(typeInfoPtrPtr)
-        assert (typeInfoPtr.type == codegen.kTypeInfoPtr)
 
         val owner = descriptor.containingDeclaration as ClassDescriptor
+
+        val typeInfoPtr: LLVMValueRef = if (owner.isObjCClass()) {
+            call(context.llvm.getObjCKotlinTypeInfo, listOf(args.first()))
+        } else {
+            val typeInfoPtrPtr = LLVMBuildStructGEP(functionGenerationContext.builder, args[0], 0 /* type_info */, "")!!
+            functionGenerationContext.load(typeInfoPtrPtr)
+        }
+        assert (typeInfoPtr.type == codegen.kTypeInfoPtr)
         val llvmMethod = if (!owner.isInterface) {
             // If this is a virtual method of the class - we can call via vtable.
             val index = context.getVtableBuilder(owner).vtableIndex(descriptor)
@@ -2068,6 +2221,10 @@ internal class CodeGeneratorVisitor(val context: Context, val lifetimes: Map<IrE
         val constructedClass = functionGenerationContext.constructedClass!!
         val thisPtr = currentCodeContext.genGetValue(constructedClass.thisAsReceiverParameter)
 
+        if (constructedClass.isObjCClass()) {
+            return codegen.theUnitInstanceRef.llvm
+        }
+
         val thisPtrArgType = codegen.getLLVMType(descriptor.allParameters[0].type)
         val thisPtrArg = if (thisPtr.type == thisPtrArgType) {
             thisPtr

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

@@ -0,0 +1,94 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.backend.konan.llvm
+
+import llvm.LLVMStoreSizeOfType
+import org.jetbrains.kotlin.backend.konan.Context
+import org.jetbrains.kotlin.backend.konan.ObjCMethodInfo
+import org.jetbrains.kotlin.backend.konan.descriptors.contributedMethods
+import org.jetbrains.kotlin.backend.konan.getObjCMethodInfo
+import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.descriptors.ConstructorDescriptor
+import org.jetbrains.kotlin.descriptors.isFinalClass
+import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
+import org.jetbrains.kotlin.resolve.descriptorUtil.getSuperClassNotAny
+import org.jetbrains.kotlin.resolve.descriptorUtil.getSuperInterfaces
+
+internal class KotlinObjCClassInfoGenerator(override val context: Context) : ContextUtils {
+    fun generate(descriptor: ClassDescriptor) {
+        assert(descriptor.isFinalClass)
+
+        val objCLLvmDeclarations = context.llvmDeclarations.forClass(descriptor).objCDeclarations!!
+
+        val instanceMethods = descriptor.generateMethodDescs()
+
+        val companionObjectDescriptor = descriptor.companionObjectDescriptor
+        val classMethods = companionObjectDescriptor?.generateMethodDescs() ?: emptyList()
+
+        val superclassName = descriptor.getSuperClassNotAny()!!.name.asString()
+        val protocolNames = descriptor.getSuperInterfaces().map { it.name.asString().removeSuffix("Protocol") }
+
+        val bodySize =
+                LLVMStoreSizeOfType(llvmTargetData, context.llvmDeclarations.forClass(descriptor).bodyType).toInt()
+
+        val className = if (descriptor.isExported()) {
+            staticData.cStringLiteral(descriptor.fqNameSafe.asString())
+        } else {
+            NullPointer(int8Type) // Generate as anonymous.
+        }
+
+        val info = Struct(runtime.kotlinObjCClassInfo,
+                className,
+
+                staticData.cStringLiteral(superclassName),
+                staticData.placeGlobalConstArray("", int8TypePtr,
+                        protocolNames.map { staticData.cStringLiteral(it) } + NullPointer(int8Type)),
+
+                staticData.placeGlobalConstArray("", runtime.objCMethodDescription, instanceMethods),
+                Int32(instanceMethods.size),
+
+                staticData.placeGlobalConstArray("", runtime.objCMethodDescription, classMethods),
+                Int32(classMethods.size),
+
+                Int32(bodySize),
+                objCLLvmDeclarations.bodyOffsetGlobal.pointer,
+
+                descriptor.typeInfoPtr,
+                companionObjectDescriptor?.typeInfoPtr ?: NullPointer(runtime.typeInfoType),
+
+                objCLLvmDeclarations.classPointerGlobal.pointer
+        )
+
+        objCLLvmDeclarations.classInfoGlobal.setInitializer(info)
+
+        objCLLvmDeclarations.classPointerGlobal.setInitializer(NullPointer(int8Type))
+        objCLLvmDeclarations.bodyOffsetGlobal.setInitializer(Int32(0))
+    }
+
+    private fun generateMethodDesc(info: ObjCMethodInfo): ConstValue {
+        return Struct(runtime.objCMethodDescription, 
+                staticData.cStringLiteral(info.selector),
+                staticData.cStringLiteral(info.encoding),
+                constPointer(context.llvm.externalFunction(info.imp, functionType(voidType))).bitcast(int8TypePtr)
+        )
+    }
+
+    private fun ClassDescriptor.generateMethodDescs(): List<ConstValue> =
+            this.unsubstitutedMemberScope.contributedMethods.filter {
+                it.kind.isReal && it !is ConstructorDescriptor
+            }.mapNotNull { it.getObjCMethodInfo() }.map { generateMethodDesc(it) }
+}

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

@@ -21,6 +21,7 @@ import llvm.*
 import org.jetbrains.kotlin.backend.konan.Context
 import org.jetbrains.kotlin.backend.konan.KonanConfigKeys
 import org.jetbrains.kotlin.backend.konan.descriptors.*
+import org.jetbrains.kotlin.backend.konan.isKotlinObjCClass
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.serialization.deserialization.descriptors.*
 import org.jetbrains.kotlin.ir.IrElement
@@ -75,10 +76,17 @@ internal class ClassLlvmDeclarations(
         val fields: List<PropertyDescriptor>, // TODO: it is not an LLVM declaration.
         val typeInfoGlobal: StaticData.Global,
         val typeInfo: ConstPointer,
-        val singletonDeclarations: SingletonLlvmDeclarations?)
+        val singletonDeclarations: SingletonLlvmDeclarations?,
+        val objCDeclarations: KotlinObjCClassLlvmDeclarations?)
 
 internal class SingletonLlvmDeclarations(val instanceFieldRef: LLVMValueRef)
 
+internal class KotlinObjCClassLlvmDeclarations(
+        val classPointerGlobal: StaticData.Global,
+        val classInfoGlobal: StaticData.Global,
+        val bodyOffsetGlobal: StaticData.Global
+)
+
 internal class FunctionLlvmDeclarations(val llvmFunction: LLVMValueRef)
 
 internal class FieldLlvmDeclarations(val index: Int, val classBodyType: LLVMTypeRef)
@@ -236,7 +244,7 @@ private class DeclarationsGeneratorVisitor(override val context: Context) :
             "ktype:$internalName"
         }
 
-        if (!descriptor.isAbstract()) {
+        if (descriptor.typeInfoHasVtableAttached) {
             // Create the special global consisting of TypeInfo and vtable.
 
             val typeInfoGlobalName = "ktypeglobal:$internalName"
@@ -273,7 +281,14 @@ private class DeclarationsGeneratorVisitor(override val context: Context) :
             null
         }
 
-        return ClassLlvmDeclarations(bodyType, fields, typeInfoGlobal, typeInfoPtr, singletonDeclarations)
+        val objCDeclarations = if (descriptor.isKotlinObjCClass()) {
+            createKotlinObjCClassDeclarations(descriptor)
+        } else {
+            null
+        }
+
+        return ClassLlvmDeclarations(bodyType, fields, typeInfoGlobal, typeInfoPtr,
+                singletonDeclarations, objCDeclarations)
     }
 
     private fun createSingletonDeclarations(
@@ -299,6 +314,23 @@ private class DeclarationsGeneratorVisitor(override val context: Context) :
         return SingletonLlvmDeclarations(instanceFieldRef)
     }
 
+    private fun createKotlinObjCClassDeclarations(descriptor: ClassDescriptor): KotlinObjCClassLlvmDeclarations {
+        val internalName = qualifyInternalName(descriptor)
+
+        val classPointerGlobal = staticData.createGlobal(int8TypePtr, "kobjcclassptr:$internalName")
+
+        val classInfoGlobal = staticData.createGlobal(
+                context.llvm.runtime.kotlinObjCClassInfo,
+                "kobjcclassinfo:$internalName"
+        ).apply {
+            setConstant(true)
+        }
+
+        val bodyOffsetGlobal = staticData.createGlobal(int32Type, "kobjcbodyoffs:$internalName")
+
+        return KotlinObjCClassLlvmDeclarations(classPointerGlobal, classInfoGlobal, bodyOffsetGlobal)
+    }
+
     override fun visitField(declaration: IrField) {
         super.visitField(declaration)
 
@@ -330,6 +362,8 @@ private class DeclarationsGeneratorVisitor(override val context: Context) :
     override fun visitFunction(declaration: IrFunction) {
         super.visitFunction(declaration)
 
+        if (!declaration.descriptor.kind.isReal) return
+
         val descriptor = declaration.descriptor
         val llvmFunctionType = getLlvmFunctionType(descriptor)
 

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

@@ -19,6 +19,7 @@ package org.jetbrains.kotlin.backend.konan.llvm
 import llvm.*
 import org.jetbrains.kotlin.backend.konan.Context
 import org.jetbrains.kotlin.backend.konan.descriptors.*
+import org.jetbrains.kotlin.backend.konan.isExternalObjCClassMethod
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.name.FqName
@@ -166,11 +167,18 @@ internal class RTTIGenerator(override val context: Context) : ContextUtils {
 
         val typeInfoGlobal = llvmDeclarations.typeInfoGlobal
 
-        val typeInfoGlobalValue = if (classDesc.isAbstract()) {
+        val typeInfoGlobalValue = if (!classDesc.typeInfoHasVtableAttached) {
             typeInfo
         } else {
             // TODO: compile-time resolution limits binary compatibility
-            val vtableEntries = context.getVtableBuilder(classDesc).vtableEntries.map { it.implementation.entryPointAddress }
+            val vtableEntries = context.getVtableBuilder(classDesc).vtableEntries.map {
+                val implementation = it.implementation
+                if (implementation.isExternalObjCClassMethod()) {
+                    NullPointer(int8Type)
+                } else {
+                    implementation.entryPointAddress
+                }
+            }
             val vtable = ConstArray(int8TypePtr, vtableEntries)
             Struct(typeInfo, vtable)
         }

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

@@ -53,4 +53,7 @@ class Runtime(bitcodeFile: String) {
     val dataLayout = LLVMGetDataLayout(llvmModule)!!.toKString()
 
     val targetData = LLVMCreateTargetData(dataLayout)!!
+
+    val kotlinObjCClassInfo by lazy { getStructType("KotlinObjCClassInfo") }
+    val objCMethodDescription by lazy { getStructType("ObjCMethodDescription") }
 }

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

@@ -152,6 +152,10 @@ internal class StaticData(override val context: Context): ContextUtils {
     }
 
     private val stringLiterals = mutableMapOf<String, ConstPointer>()
+    private val cStringLiterals = mutableMapOf<String, ConstPointer>()
+
+    fun cStringLiteral(value: String) =
+            cStringLiterals.getOrPut(value) { placeCStringLiteral(value) }
 
     fun kotlinStringLiteral(type: KotlinType, value: IrConst<String>) =
         stringLiterals.getOrPut(value.value) { createKotlinStringLiteral(type, value) }

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

@@ -41,3 +41,9 @@ internal fun StaticData.createAlias(name: String, aliasee: ConstPointer): ConstP
     val alias = LLVMAddAlias(context.llvmModule, aliasee.llvmType, aliasee.llvm, name)!!
     return constPointer(alias)
 }
+
+internal fun StaticData.placeCStringLiteral(value: String): ConstPointer {
+    val chars = value.toByteArray(Charsets.UTF_8).map { Int8(it) } + Int8(0)
+
+    return placeGlobalConstArray("", int8Type, chars)
+}

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

@@ -20,40 +20,282 @@ import org.jetbrains.kotlin.backend.common.FileLoweringPass
 import org.jetbrains.kotlin.backend.common.descriptors.allParameters
 import org.jetbrains.kotlin.backend.common.lower.IrBuildingTransformer
 import org.jetbrains.kotlin.backend.common.lower.at
-import org.jetbrains.kotlin.backend.konan.Context
+import org.jetbrains.kotlin.backend.common.lower.irBlock
-import org.jetbrains.kotlin.backend.konan.ValueType
+import org.jetbrains.kotlin.backend.common.peek
-import org.jetbrains.kotlin.backend.konan.isRepresentedAs
+import org.jetbrains.kotlin.backend.common.pop
-import org.jetbrains.kotlin.backend.konan.reportCompilationError
+import org.jetbrains.kotlin.backend.common.push
+import org.jetbrains.kotlin.backend.konan.*
+import org.jetbrains.kotlin.backend.konan.descriptors.getStringValue
+import org.jetbrains.kotlin.backend.konan.descriptors.isInterface
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
-import org.jetbrains.kotlin.descriptors.ClassConstructorDescriptor
+import org.jetbrains.kotlin.descriptors.*
-import org.jetbrains.kotlin.ir.builders.IrBuilder
+import org.jetbrains.kotlin.ir.IrStatement
-import org.jetbrains.kotlin.ir.builders.irCall
+import org.jetbrains.kotlin.ir.builders.*
+import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrFile
 import org.jetbrains.kotlin.ir.expressions.*
-import org.jetbrains.kotlin.ir.expressions.impl.IrConstImpl
+import org.jetbrains.kotlin.ir.expressions.impl.*
-import org.jetbrains.kotlin.ir.expressions.impl.IrFunctionReferenceImpl
+import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
-import org.jetbrains.kotlin.ir.expressions.impl.IrGetObjectValueImpl
 import org.jetbrains.kotlin.ir.util.defaultType
 import org.jetbrains.kotlin.ir.util.functions
 import org.jetbrains.kotlin.ir.util.getArguments
-import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
 import org.jetbrains.kotlin.ir.visitors.transformChildrenVoid
+import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.OverridingUtil
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
+import org.jetbrains.kotlin.resolve.descriptorUtil.getSuperClassNotAny
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.TypeUtils
 import org.jetbrains.kotlin.types.typeUtil.isSubtypeOf
 
-internal class InteropLoweringPart1(val context: Context) : IrElementTransformerVoid(), FileLoweringPass {
+internal class InteropLoweringPart1(val context: Context) : IrBuildingTransformer(context), FileLoweringPass {
+
+    private val symbols get() = context.ir.symbols
+    private val symbolTable get() = symbols.symbolTable
+
+    lateinit var currentFile: IrFile
+
     override fun lower(irFile: IrFile) {
+        currentFile = irFile
         irFile.transformChildrenVoid(this)
     }
 
+    private fun IrBuilderWithScope.callAlloc(classSymbol: IrClassSymbol): IrExpression {
+        return irCall(symbols.interopAllocObjCObject, listOf(classSymbol.descriptor.defaultType)).apply {
+            putValueArgument(0, getObjCClass(classSymbol))
+        }
+    }
+
+    private fun IrBuilderWithScope.getObjCClass(classSymbol: IrClassSymbol): IrExpression {
+        val classDescriptor = classSymbol.descriptor
+        assert(!classDescriptor.isObjCMetaClass())
+
+        if (classDescriptor.isExternalObjCClass()) {
+            val companionObject = classDescriptor.companionObjectDescriptor!!
+            if (companionObject.unsubstitutedPrimaryConstructor != scope.scopeOwner) {
+                // Optimization: get class pointer from companion object thus avoiding lookup by name.
+                return irCall(symbols.interopObjCObjectRawValueGetter).apply {
+                    extensionReceiver = irGetObject(symbolTable.referenceClass(companionObject))
+                }
+            }
+        }
+        return irCall(symbols.interopGetObjCClass, listOf(classDescriptor.defaultType))
+    }
+
+    private val outerClasses = mutableListOf<IrClass>()
+
+    override fun visitClass(declaration: IrClass): IrStatement {
+        if (declaration.descriptor.isKotlinObjCClass()) {
+            checkKotlinObjCClass(declaration)
+        }
+
+        outerClasses.push(declaration)
+        try {
+            return super.visitClass(declaration)
+        } finally {
+            outerClasses.pop()
+        }
+    }
+
+    private fun checkKotlinObjCClass(irClass: IrClass) {
+        val kind = irClass.descriptor.kind
+        if (kind != ClassKind.CLASS && kind != ClassKind.OBJECT) {
+            context.reportCompilationError(
+                    "Only classes are supported as subtypes of Objective-C types",
+                    currentFile, irClass
+            )
+        }
+
+        if (!irClass.descriptor.isFinalClass) {
+            context.reportCompilationError(
+                    "Non-final Kotlin subclasses of Objective-C classes are not yet supported",
+                    currentFile, irClass
+            )
+        }
+
+        var hasObjCClassSupertype = false
+        irClass.descriptor.defaultType.constructor.supertypes.forEach {
+            val descriptor = it.constructor.declarationDescriptor as ClassDescriptor
+            if (!descriptor.isObjCClass()) {
+                context.reportCompilationError(
+                        "Mixing Kotlin and Objective-C supertypes is not supported",
+                        currentFile, irClass
+                )
+            }
+
+            if (descriptor.kind == ClassKind.CLASS) {
+                hasObjCClassSupertype = true
+            }
+        }
+
+        if (!hasObjCClassSupertype) {
+            context.reportCompilationError(
+                    "Kotlin implementation of Objective-C protocol must have Objective-C superclass (e.g. NSObject)",
+                    currentFile, irClass
+            )
+        }
+
+    }
+
+    override fun visitDelegatingConstructorCall(expression: IrDelegatingConstructorCall): IrExpression {
+        expression.transformChildrenVoid()
+
+        builder.at(expression)
+
+        val constructedClass = outerClasses.peek()!!
+        val constructedClassDescriptor = constructedClass.descriptor
+
+        if (!constructedClassDescriptor.isObjCClass()) {
+            return expression
+        }
+
+        constructedClassDescriptor.containingDeclaration.let { classContainer ->
+            if (classContainer is ClassDescriptor && classContainer.isObjCClass() &&
+                    constructedClassDescriptor == classContainer.companionObjectDescriptor) {
+
+                val outerConstructedClass = outerClasses[outerClasses.lastIndex - 1]
+                assert (outerConstructedClass.descriptor == classContainer)
+
+                assert(expression.getArguments().isEmpty())
+
+                return builder.irBlock(expression) {
+                    +expression // Required for the IR to be valid, will be ignored in codegen.
+                    +irCall(symbols.interopObjCObjectInitFromPtr).apply {
+                        extensionReceiver = irGet(constructedClass.thisReceiver!!.symbol)
+                        putValueArgument(0, getObjCClass(outerConstructedClass.symbol))
+                    }
+                }
+            }
+        }
+
+        if (!constructedClassDescriptor.isExternalObjCClass() &&
+                expression.descriptor.constructedClass.isExternalObjCClass()) {
+
+            // Calling super constructor from Kotlin Objective-C class.
+
+            assert(constructedClassDescriptor.getSuperClassNotAny() == expression.descriptor.constructedClass)
+
+            val initMethod = getObjCInitMethod(expression.descriptor)!!
+            val initMethodInfo = initMethod.getExternalObjCMethodInfo()!!
+
+            assert(expression.dispatchReceiver == null)
+            assert(expression.extensionReceiver == null)
+
+            val initCall = builder.genLoweredObjCMethodCall(
+                    initMethodInfo,
+                    superQualifier = symbolTable.referenceClass(expression.descriptor.constructedClass),
+                    receiver = builder.callAlloc(constructedClass.symbol),
+                    arguments = initMethod.valueParameters.map { expression.getValueArgument(it)!! }
+            )
+
+            val superConstructor = symbolTable.referenceConstructor(
+                    expression.descriptor.constructedClass.constructors.single { it.valueParameters.size == 0 }
+            )
+
+            return builder.irBlock(expression) {
+                // Required for the IR to be valid, will be ignored in codegen:
+                +IrDelegatingConstructorCallImpl(startOffset, endOffset, superConstructor, superConstructor.descriptor)
+
+                +irCall(symbols.interopObjCObjectInitFrom).apply {
+                    extensionReceiver = irGet(constructedClass.thisReceiver!!.symbol)
+                    putValueArgument(0, initCall)
+                }
+            }
+        }
+
+        return expression
+    }
+
+    private fun IrBuilderWithScope.genLoweredObjCMethodCall(info: ObjCMethodInfo, superQualifier: IrClassSymbol?,
+                                         receiver: IrExpression, arguments: List<IrExpression>): IrExpression {
+
+        val superClass = superQualifier?.let { getObjCClass(it) } ?:
+                irCall(symbols.getNativeNullPtr)
+
+        val bridge = symbolTable.referenceSimpleFunction(info.bridge)
+        return irCall(bridge).apply {
+            putValueArgument(0, superClass)
+            putValueArgument(1, receiver)
+
+            assert(arguments.size + 2 == info.bridge.valueParameters.size)
+            arguments.forEachIndexed { index, argument ->
+                putValueArgument(index + 2, argument)
+            }
+        }
+    }
+
+    private fun getObjCInitMethod(descriptor: ConstructorDescriptor): FunctionDescriptor? {
+        return descriptor.annotations.findAnnotation(FqName("kotlinx.cinterop.ObjCConstructor"))?.let {
+            val initSelector = it.getStringValue("initSelector")
+            descriptor.constructedClass.unsubstitutedMemberScope.getContributedDescriptors().asSequence()
+                    .filterIsInstance<FunctionDescriptor>()
+                    .single { it.getExternalObjCMethodInfo()?.selector == initSelector }
+        }
+    }
+
     override fun visitCall(expression: IrCall): IrExpression {
         expression.transformChildrenVoid()
 
-        return when (expression.descriptor.original) {
+        val descriptor = expression.descriptor.original
+
+        if (descriptor is ConstructorDescriptor) {
+            val initMethod = getObjCInitMethod(descriptor)
+
+            if (initMethod != null) {
+                val arguments = descriptor.valueParameters.map { expression.getValueArgument(it)!! }
+                assert(expression.extensionReceiver == null)
+                assert(expression.dispatchReceiver == null)
+
+                builder.at(expression)
+
+                return builder.genLoweredObjCMethodCall(
+                        initMethod.getExternalObjCMethodInfo()!!,
+                        superQualifier = null,
+                        receiver = builder.callAlloc(symbolTable.referenceClass(descriptor.constructedClass)),
+                        arguments = arguments
+                )
+            }
+        }
+
+        descriptor.getExternalObjCMethodInfo()?.let { methodInfo ->
+            val isInteropStubsFile =
+                    currentFile.fileAnnotations.any { it.fqName ==  FqName("kotlinx.cinterop.InteropStubs") }
+
+            // Special case: bridge from Objective-C method implementation template to Kotlin method;
+            // handled in CodeGeneratorVisitor.callVirtual.
+            val useKotlinDispatch = isInteropStubsFile &&
+                    builder.scope.scopeOwner.annotations.hasAnnotation(FqName("konan.internal.ExportForCppRuntime"))
+
+            if (!useKotlinDispatch) {
+                val arguments = descriptor.valueParameters.map { expression.getValueArgument(it)!! }
+                assert(expression.extensionReceiver == null)
+
+                if (expression.superQualifier?.isObjCMetaClass() == true) {
+                    context.reportCompilationError(
+                            "Super calls to Objective-C meta classes are not supported yet",
+                            currentFile, expression
+                    )
+                }
+
+                if (expression.superQualifier?.isInterface == true) {
+                    context.reportCompilationError(
+                            "Super calls to Objective-C protocols are not allowed",
+                            currentFile, expression
+                    )
+                }
+
+                builder.at(expression)
+                return builder.genLoweredObjCMethodCall(
+                        methodInfo,
+                        superQualifier = expression.superQualifierSymbol,
+                        receiver = expression.dispatchReceiver!!,
+                        arguments = arguments
+                )
+            }
+        }
+
+        return when (descriptor) {
             context.interopBuiltIns.typeOf -> {
                 val typeArgument = expression.getSingleTypeArgument()
                 val classDescriptor = TypeUtils.getClassDescriptor(typeArgument)
@@ -65,8 +307,8 @@ internal class InteropLoweringPart1(val context: Context) : IrElementTransformer
                             error("native variable class $classDescriptor must have the companion object")
 
                     IrGetObjectValueImpl(
-                            expression.startOffset, expression.endOffset,
+                            expression.startOffset, expression.endOffset, companionObjectDescriptor.defaultType,
-                            companionObjectDescriptor.defaultType, companionObjectDescriptor
+                            symbolTable.referenceClass(companionObjectDescriptor)
                     )
                 }
             }

backend.native/konan.properties

@@ -37,7 +37,7 @@ libffiDir.osx = libffi-3.2.1-2-darwin-macos
 llvmLtoFlags.osx =
 llvmLtoOptFlags.osx = -O3 -function-sections
 llvmLtoNooptFlags.osx = -O1
-linkerKonanFlags.osx = -lc++
+linkerKonanFlags.osx = -lc++ -lobjc
 linkerOptimizationFlags.osx = -dead_strip
 linkerDebugFlags.osx = -S
 osVersionMinFlagLd.osx = -macosx_version_min
@@ -63,7 +63,7 @@ llvmLtoFlags.ios =
 llvmLtoOptFlags.ios = -O3 -function-sections
 linkerDebugFlags.ios = -S
 llvmLtoNooptFlags.ios = -O1
-linkerKonanFlags.ios = -lc++
+linkerKonanFlags.ios = -lc++ -lobjc
 linkerOptimizationFlags.ios = -dead_strip
 osVersionMinFlagLd.ios = -iphoneos_version_min
 osVersionMinFlagClang.ios = -miphoneos-version-min
@@ -83,7 +83,7 @@ libffiDir.ios_sim = libffi-3.2.1-2-darwin-ios-sim
 llvmLtoFlags.ios_sim =
 llvmLtoOptFlags.ios_sim = -O3 -function-sections
 llvmLtoNooptFlags.ios_sim = -O1
-linkerKonanFlags.ios_sim = -lc++
+linkerKonanFlags.ios_sim = -lc++ -lobjc
 linkerOptimizationFlags.ios_sim = -dead_strip
 linkerDebugFlags.ios_sim = -S
 osVersionMinFlagLd.ios_sim = -ios_simulator_version_min

backend.native/tests/build.gradle

@@ -1995,6 +1995,13 @@ kotlinNativeInterop {
             linkerOpts '-framework', 'OpenGL', '-framework', 'GLUT'
             flavor 'native'
         }
+
+        objcSmoke {
+            defFile 'interop/objc/objcSmoke.def'
+            headers "$projectDir/interop/objc/smoke.h"
+            linkerOpts "-L$buildDir",  "-lobjcsmoke"
+            flavor 'native'
+        }
     }
 }
 
@@ -2057,4 +2064,19 @@ if (isMac()) {
         source = "interop/basics/opengl_teapot.kt"
         interop = 'opengl'
     }
+
+    task interop_objc_smoke(type: RunInteropKonanTest) {
+        goldValue = "Hello, World!\nKotlin says: Hello, everybody!\nHello from Kotlin\n2, 1\nDeallocated\nDeallocated\n"
+
+        source = "interop/objc/smoke.kt"
+        interop = 'objcSmoke'
+
+        doFirst {
+            execClang {
+                args "$projectDir/interop/objc/smoke.m"
+                args "-lobjc", '-fobjc-arc'
+                args '-fPIC', '-shared', '-o', "$buildDir/libobjcsmoke.dylib"
+            }
+        }
+    }
 }

backend.native/tests/interop/objc/objcSmoke.def

@@ -0,0 +1,2 @@
+language = Objective-C
+headerFilter = **/smoke.h

backend.native/tests/interop/objc/smoke.h

@@ -0,0 +1,24 @@
+#import <objc/NSObject.h>
+
+@protocol Printer
+@required
+-(void)print:(const char*)string;
+@end;
+
+@interface Foo : NSObject
+@property NSString* name;
+-(void)hello;
+-(void)helloWithPrinter:(id <Printer>)printer;
+@end;
+
+@protocol MutablePair
+@required
+@property (readonly) int first;
+@property (readonly) int second;
+
+-(void)update:(int)index add:(int)delta;
+-(void)update:(int)index sub:(int)delta;
+
+@end;
+
+void replacePairElements(id <MutablePair> pair, int first, int second);

backend.native/tests/interop/objc/smoke.kt

@@ -0,0 +1,55 @@
+import kotlinx.cinterop.*
+import objcSmoke.*
+
+fun main(args: Array<String>) {
+    autoreleasepool {
+        run()
+    }
+}
+
+fun run() {
+    val foo = Foo()
+    foo.hello()
+    foo.name = "everybody"
+    foo.helloWithPrinter(object : NSObject(), PrinterProtocol {
+        override fun print(string: CPointer<ByteVar>?) {
+            println("Kotlin says: " + string?.toKString())
+        }
+    })
+
+    Bar().hello()
+
+    val pair = MutablePairImpl(42, 17)
+    replacePairElements(pair, 1, 2)
+    pair.swap()
+    println("${pair.first}, ${pair.second}")
+}
+
+fun MutablePairProtocol.swap() {
+    update(0, add = second)
+    update(1, sub = first)
+    update(0, add = second)
+    update(1, sub = second*2)
+}
+
+class Bar : Foo() {
+    override fun helloWithPrinter(printer: PrinterProtocol) = memScoped {
+        printer.print("Hello from Kotlin".cstr.getPointer(memScope))
+    }
+}
+
+@Suppress("CONFLICTING_OVERLOADS")
+class MutablePairImpl(first: Int, second: Int) : NSObject(), MutablePairProtocol {
+    private var elements = intArrayOf(first, second)
+
+    override fun first() = elements.first()
+    override fun second() = elements.last()
+
+    override fun update(index: Int, add: Int) {
+        elements[index] += add
+    }
+
+    override fun update(index: Int, sub: Int) {
+        elements[index] -= sub
+    }
+}

backend.native/tests/interop/objc/smoke.m

@@ -0,0 +1,46 @@
+#import <stdio.h>
+#import <Foundation/NSString.h>
+#import "smoke.h"
+
+@interface CPrinter : NSObject <Printer>
+-(void)print:(const char*)string;
+@end;
+
+@implementation CPrinter
+-(void)print:(const char*)string {
+    printf("%s\n", string);
+    fflush(stdout);
+}
+@end;
+
+@implementation Foo
+
+@synthesize name;
+
+-(instancetype)init {
+    if (self = [super init]) {
+        self.name = @"World";
+    }
+    return self;
+}
+
+-(void)hello {
+    CPrinter* printer = [[CPrinter alloc] init];
+    [self helloWithPrinter:printer];
+}
+
+-(void)helloWithPrinter:(id <Printer>)printer {
+    NSString* message = [NSString stringWithFormat:@"Hello, %@!", self.name];
+    [printer print:message.UTF8String];
+}
+
+-(void)dealloc {
+    printf("Deallocated\n");
+}
+
+@end;
+
+void replacePairElements(id <MutablePair> pair, int first, int second) {
+    [pair update:0 add:(first - pair.first)];
+    [pair update:1 sub:(pair.second - second)];
+}

buildSrc/plugins/src/main/groovy/org/jetbrains/kotlin/CompileToBitcode.groovy

@@ -124,7 +124,10 @@ class CompileCppToBitcode extends DefaultTask {
             args "-I$headersDir"
 
             args '-c', '-emit-llvm'
-            args project.fileTree(srcDir).include('**/*.cpp')
+            args project.fileTree(srcDir) {
+                include('**/*.cpp')
+                include('**/*.mm') // Objective-C++
+            }
         }
 
         project.exec {

runtime/src/main/cpp/Memory.cpp

@@ -350,6 +350,31 @@ ContainerHeader* AllocContainer(size_t size) {
   return result;
 }
 
+extern "C" {
+void objc_release(void* ptr);
+}
+
+inline void runDeallocationHooks(ObjHeader* obj) {
+#if KONAN_OBJC_INTEROP
+  if (obj->type_info() == theObjCPointerHolderTypeInfo) {
+    void* objcPtr =  *reinterpret_cast<void**>(obj + 1); // TODO: use more reliable layout description
+    objc_release(objcPtr);
+  }
+#endif
+}
+
+static inline void DeinitInstanceBodyImpl(const TypeInfo* typeInfo, void* body) {
+  for (int index = 0; index < typeInfo->objOffsetsCount_; index++) {
+    ObjHeader** location = reinterpret_cast<ObjHeader**>(
+        reinterpret_cast<uintptr_t>(body) + typeInfo->objOffsets_[index]);
+    UpdateRef(location, nullptr);
+  }
+}
+
+void DeinitInstanceBody(const TypeInfo* typeInfo, void* body) {
+  DeinitInstanceBodyImpl(typeInfo, body);
+}
+
 void FreeContainer(ContainerHeader* header) {
   RuntimeAssert(!isPermanent(header), "this kind of container shalln't be freed");
 #if TRACE_MEMORY
@@ -366,13 +391,12 @@ void FreeContainer(ContainerHeader* header) {
   ObjHeader* obj = reinterpret_cast<ObjHeader*>(header + 1);
 
   for (int index = 0; index < header->objectCount_; index++) {
+    runDeallocationHooks(obj);
+
     const TypeInfo* typeInfo = obj->type_info();
 
-    for (int index = 0; index < typeInfo->objOffsetsCount_; index++) {
+    DeinitInstanceBodyImpl(typeInfo, reinterpret_cast<void*>(obj + 1));
-      ObjHeader** location = reinterpret_cast<ObjHeader**>(
+
-          reinterpret_cast<uintptr_t>(obj + 1) + typeInfo->objOffsets_[index]);
-      UpdateRef(location, nullptr);
-    }
     // Object arrays are *special*.
     if (typeInfo == theArrayTypeInfo) {
       ArrayHeader* array = obj->array();
@@ -399,6 +423,15 @@ void FreeContainerNoRef(ContainerHeader* header) {
 #if USE_GC
   removeFreeable(memoryState, header);
 #endif
+  ObjHeader* obj = reinterpret_cast<ObjHeader*>(header + 1);
+
+  for (int index = 0; index < header->objectCount_; index++) {
+    runDeallocationHooks(obj);
+
+    obj = reinterpret_cast<ObjHeader*>(
+      reinterpret_cast<uintptr_t>(obj) + objectSize(obj));
+  }
+
   memoryState->allocCount--;
   konanFreeMemory(header);
 }

runtime/src/main/cpp/Memory.h

@@ -322,6 +322,7 @@ void DeinitMemory(MemoryState*);
 //
 OBJ_GETTER(AllocInstance, const TypeInfo* type_info) RUNTIME_NOTHROW;
 OBJ_GETTER(AllocArrayInstance, const TypeInfo* type_info, uint32_t elements) RUNTIME_NOTHROW;
+void DeinitInstanceBody(const TypeInfo* typeInfo, void* body);
 OBJ_GETTER(InitInstance, ObjHeader** location, const TypeInfo* type_info,
            void (*ctor)(ObjHeader*));
 

runtime/src/main/cpp/ObjCInterop.cpp

@@ -0,0 +1,241 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#if KONAN_OBJC_INTEROP
+
+#include <objc/objc.h>
+#include <objc/runtime.h>
+#include <objc/message.h>
+#include <cstdio>
+#include <cstdint>
+#include "Memory.h"
+#include "Natives.h"
+#include "Utils.h"
+
+extern "C" {
+
+struct KotlinClassData {
+  const TypeInfo* typeInfo;
+  int32_t bodyOffset;
+};
+
+static inline struct KotlinClassData* GetKotlinClassData(Class clazz) {
+  void* ivars = object_getIndexedIvars(reinterpret_cast<id>(clazz));
+  return static_cast<struct KotlinClassData*>(ivars);
+}
+
+static inline void SetKotlinTypeInfo(Class clazz, const TypeInfo* typeInfo) {
+  GetKotlinClassData(clazz)->typeInfo = typeInfo;
+}
+
+const TypeInfo* GetObjCKotlinTypeInfo(const ObjHeader* obj) {
+  void* objcPtr =  *reinterpret_cast<void * const *>(obj + 1); // TODO: use more reliable layout description
+  Class clazz = object_getClass(reinterpret_cast<id>(objcPtr));
+  return GetKotlinClassData(clazz)->typeInfo;
+}
+
+id objc_msgSendSuper2(struct objc_super *super, SEL op, ...);
+
+static void DeallocImp(id self, SEL _cmd) {
+  // TODO: doesn't support overriding Kotlin classes.
+  Class clazz = object_getClass(self);
+  RuntimeAssert(clazz != nullptr, "Must not be null");
+
+  struct KotlinClassData* classData = GetKotlinClassData(clazz);
+  void* body = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(self) + classData->bodyOffset);
+
+  const TypeInfo* typeInfo = classData->typeInfo;
+  DeinitInstanceBody(typeInfo, body);
+
+  // Call super.dealloc:
+  struct objc_super s = {self, clazz};
+  auto messenger = reinterpret_cast<void (*) (struct objc_super*, SEL _cmd)>(objc_msgSendSuper2);
+  messenger(&s, _cmd);
+}
+
+static void AddDeallocMethod(Class clazz) {
+  Class nsObjectClass = objc_getClass("NSObject");
+  RuntimeAssert(nsObjectClass != nullptr, "NSObject class not found");
+
+  SEL deallocSelector = sel_registerName("dealloc");
+  Method nsObjectDeallocMethod = class_getInstanceMethod(nsObjectClass, deallocSelector);
+  RuntimeAssert(nsObjectDeallocMethod != nullptr, "[NSObject dealloc] method not found");
+
+  const char* nsObjectDeallocMethodTypeEncoding = method_getTypeEncoding(nsObjectDeallocMethod);
+  RuntimeAssert(nsObjectDeallocMethodTypeEncoding != nullptr, "[NSObject dealloc] method has no encoding provided");
+
+  // TODO: something of the above can be cached.
+
+  BOOL added = class_addMethod(clazz, deallocSelector, (IMP)DeallocImp, nsObjectDeallocMethodTypeEncoding);
+  RuntimeAssert(added, "Unable to add dealloc method to Objective-C class");
+}
+
+struct ObjCMethodDescription {
+  const char* selector;
+  const char* encoding;
+  const void* imp;
+};
+
+struct KotlinObjCClassInfo {
+  const char* name;
+
+  const char* superclassName;
+  const char** protocolNames;
+
+  const struct ObjCMethodDescription* instanceMethods;
+  int32_t instanceMethodsNum;
+
+  const struct ObjCMethodDescription* classMethods;
+  int32_t classMethodsNum;
+
+  int32_t bodySize;
+  int32_t* bodyOffset;
+
+  const TypeInfo* typeInfo;
+  const TypeInfo* metaTypeInfo;
+
+  void** createdClass;
+};
+
+static void AddMethods(Class clazz, const struct ObjCMethodDescription* methods, int32_t methodsNum) {
+  for (int32_t i = 0; i < methodsNum; ++i) {
+    const struct ObjCMethodDescription* method = &methods[i];
+    BOOL added = class_addMethod(clazz, sel_registerName(method->selector), (IMP)method->imp, method->encoding);
+    RuntimeAssert(added == YES, "Unable to add method to Objective-C class");
+  }
+}
+
+static SimpleMutex classCreationMutex;
+static int anonymousClassNextId = 0;
+
+void* CreateKotlinObjCClass(const KotlinObjCClassInfo* info) {
+  LockGuard<SimpleMutex> lockGuard(classCreationMutex);
+
+  void* createdClass = *info->createdClass;
+  if (createdClass != nullptr) {
+    return createdClass;
+  }
+
+  char classNameBuffer[64];
+  const char* className = info->name;
+  if (className == nullptr) {
+    snprintf(classNameBuffer, sizeof(classNameBuffer), "kobjc%d", anonymousClassNextId++);
+    className = classNameBuffer;
+  }
+
+  Class superclass = objc_getClass(info->superclassName);
+  Class newClass = objc_allocateClassPair(superclass, className, sizeof(struct KotlinClassData));
+  RuntimeAssert(newClass != nullptr, "Failed to allocate Objective-C class");
+
+  Class newMetaclass = object_getClass(reinterpret_cast<id>(newClass));
+
+  for (size_t i = 0;; ++i) {
+    const char* protocolName = info->protocolNames[i];
+    if (protocolName == nullptr) break;
+    Protocol* proto = objc_getProtocol(protocolName);
+    if (proto != nullptr) {
+      BOOL added = class_addProtocol(newClass, proto);
+      RuntimeAssert(added == YES, "Unable to add protocol to Objective-C class");
+      added = class_addProtocol(newMetaclass, proto);
+      RuntimeAssert(added == YES, "Unable to add protocol to Objective-C metaclass");
+    }
+  }
+
+  AddDeallocMethod(newClass);
+
+  AddMethods(newClass, info->instanceMethods, info->instanceMethodsNum);
+  AddMethods(newMetaclass, info->classMethods, info->classMethodsNum);
+
+  SetKotlinTypeInfo(newClass, info->typeInfo);
+  SetKotlinTypeInfo(newMetaclass, info->metaTypeInfo);
+
+  char bodyTypeEncoding[16];
+  snprintf(bodyTypeEncoding, sizeof(bodyTypeEncoding), "[%dc]", info->bodySize);
+  BOOL added = class_addIvar(newClass, "kotlinBody", info->bodySize, /* log2(align) = */ 3, bodyTypeEncoding);
+  RuntimeAssert(added == YES, "Unable to add ivar to Objective-C class");
+
+  objc_registerClassPair(newClass);
+
+  Ivar body = class_getInstanceVariable(newClass, "kotlinBody");
+  RuntimeAssert(body != nullptr, "Unable to get ivar added to Objective-C class");
+  int32_t offset = (int32_t)ivar_getOffset(body);
+  GetKotlinClassData(newClass)->bodyOffset = offset;
+  *info->bodyOffset = offset;
+
+  *info->createdClass = newClass;
+  return newClass;
+}
+
+void* objc_autoreleasePoolPush();
+void objc_autoreleasePoolPop(void* ptr);
+id objc_allocWithZone(Class clazz);
+id objc_retain(id ptr);
+void objc_release(id ptr);
+
+void* Kotlin_objc_autoreleasePoolPush() {
+  return objc_autoreleasePoolPush();
+}
+
+void Kotlin_objc_autoreleasePoolPop(void* ptr) {
+  objc_autoreleasePoolPop(ptr);
+}
+
+id Kotlin_objc_allocWithZone(Class clazz) {
+  return objc_allocWithZone(clazz);
+}
+
+id Kotlin_objc_retain(id ptr) {
+  return objc_retain(ptr);
+}
+
+void Kotlin_objc_release(id ptr) {
+  objc_release(ptr);
+}
+
+} // extern "C"
+
+#else  // KONAN_OBJC_INTEROP
+
+#include "Assert.h"
+
+extern "C" {
+
+void* Kotlin_objc_autoreleasePoolPush() {
+  RuntimeAssert(false, "Objective-C interop is disabled");
+  return nullptr;
+}
+
+void Kotlin_objc_autoreleasePoolPop(void* ptr) {
+  RuntimeAssert(false, "Objective-C interop is disabled");
+}
+
+void* Kotlin_objc_allocWithZone(void* clazz) {
+  RuntimeAssert(false, "Objective-C interop is disabled");
+  return nullptr;
+}
+
+void* Kotlin_objc_retain(void* ptr) {
+  RuntimeAssert(false, "Objective-C interop is disabled");
+  return nullptr;
+}
+
+void Kotlin_objc_release(void* ptr) {
+  RuntimeAssert(false, "Objective-C interop is disabled");
+}
+
+} // extern "C"
+
+#endif // KONAN_OBJC_INTEROP

runtime/src/main/cpp/ObjCInteropUtils.mm

@@ -0,0 +1,88 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "Natives.h"
+
+#if KONAN_OBJC_INTEROP
+
+#import <objc/runtime.h>
+#import <Foundation/NSString.h>
+
+namespace {
+  Class nsStringClass = nullptr;
+
+  Class getNSStringClass() {
+    Class result = nsStringClass;
+    if (result == nullptr) {
+      // Lookup dynamically to avoid direct reference to Foundation:
+      result = objc_getClass("NSString");
+      RuntimeAssert(result != nullptr, "NSString class not found");
+      nsStringClass = result;
+    }
+    return result;
+  }
+}
+
+extern "C" {
+
+NSString* CreateNSStringFromKString(const ArrayHeader* str) {
+  if (str == nullptr) {
+    return nullptr;
+  }
+
+  const KChar* utf16Chars = CharArrayAddressOfElementAt(str, 0);
+
+  NSString* result = [[[getNSStringClass() alloc] initWithBytes:utf16Chars
+    length:str->count_*sizeof(KChar)
+    encoding:NSUTF16LittleEndianStringEncoding] autorelease];
+
+  return result;
+}
+
+OBJ_GETTER(CreateKStringFromNSString, NSString* str) {
+  if (str == nullptr) {
+    RETURN_OBJ(nullptr);
+  }
+
+  size_t length = [str length];
+  NSRange range = {0, length};
+  ArrayHeader* result = AllocArrayInstance(theStringTypeInfo, length, OBJ_RESULT)->array();
+  KChar* rawResult = CharArrayAddressOfElementAt(result, 0);
+
+  [str getCharacters:rawResult range:range];
+
+  RETURN_OBJ(result->obj());
+}
+
+} // extern "C"
+
+#else // KONAN_OBJC_INTEROP
+
+extern "C" {
+
+void* CreateNSStringFromKString(const ArrayHeader* str) {
+  RuntimeAssert(false, "Objective-C interop is disabled");
+  return nullptr;
+}
+
+OBJ_GETTER(CreateKStringFromNSString, void* str) {
+  RuntimeAssert(false, "Objective-C interop is disabled");
+  RETURN_OBJ(nullptr);
+}
+
+} // extern "C"
+
+#endif // KONAN_OBJC_INTEROP

runtime/src/main/cpp/Types.h

@@ -83,6 +83,7 @@ extern const TypeInfo* theDoubleArrayTypeInfo;
 extern const TypeInfo* theBooleanArrayTypeInfo;
 extern const TypeInfo* theStringTypeInfo;
 extern const TypeInfo* theThrowableTypeInfo;
+extern const TypeInfo* theObjCPointerHolderTypeInfo;
 
 KBoolean IsInstance(const ObjHeader* obj, const TypeInfo* type_info) RUNTIME_PURE;
 void CheckCast(const ObjHeader* obj, const TypeInfo* type_info);

runtime/src/main/cpp/Utils.h

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <cstdint>
+#include "Assert.h"
+
+class SimpleMutex {
+ private:
+  int32_t atomicInt = 0;
+
+ public:
+  void lock() {
+    while (!__sync_bool_compare_and_swap(&atomicInt, 0, 1)) {
+      // TODO: yield.
+    }
+  }
+
+  void unlock() {
+    if (!__sync_bool_compare_and_swap(&atomicInt, 1, 0)) {
+      RuntimeAssert(false, "Unable to unlock");
+    }
+  }
+};
+
+// TODO: use std::lock_guard instead?
+template <class Mutex>
+class LockGuard {
+ public:
+  explicit LockGuard(Mutex& mutex_) : mutex(mutex_) {
+    mutex.lock();
+  }
+
+  ~LockGuard() {
+    mutex.unlock();
+  }
+
+ private:
+  Mutex& mutex;
+
+  LockGuard(const LockGuard&) = delete;
+  LockGuard& operator=(const LockGuard&) = delete;
+};

samples/objc/build.gradle

@@ -0,0 +1,15 @@
+apply plugin: 'konan'
+
+konanInterop {
+    objc {
+        target "macbook"
+    }
+}
+
+
+konanArtifacts {
+    Window {
+        useInterop 'objc'
+        target "macbook"
+    }
+}

samples/objc/src/main/c_interop/objc.def

@@ -0,0 +1,4 @@
+headers = Foundation/Foundation.h Cocoa/Cocoa.h AppKit/NSApplication.h AppKit/NSWindow.h
+headerFilter = Foundation/** Cocoa/** AppKit/**
+language = Objective-C
+linkerOpts = -framework AppKit

samples/objc/src/main/kotlin/Window.kt

@@ -0,0 +1,59 @@
+import objc.*
+import kotlinx.cinterop.*
+
+fun main(args: Array<String>) {
+    autoreleasepool {
+        runApp()
+    }
+}
+
+private fun runApp() {
+    val app = NSApplication.sharedApplication()
+
+    app.delegate = MyAppDelegate()
+    app.setActivationPolicy(NSApplicationActivationPolicy.NSApplicationActivationPolicyRegular)
+    app.activateIgnoringOtherApps(true)
+
+    app.run()
+}
+
+private class MyAppDelegate() : NSObject(), NSApplicationDelegateProtocol {
+
+    private val window: NSWindow
+
+    init {
+        val mainDisplayRect = NSScreen.mainScreen()!!.frame
+        val windowRect = mainDisplayRect.useContents {
+            NSMakeRect(
+                    origin.x + size.width * 0.25,
+                    origin.y + size.height * 0.25,
+                    size.width * 0.5,
+                    size.height * 0.5
+            )
+        }
+
+        val windowStyle = NSWindowStyleMaskTitled or NSWindowStyleMaskMiniaturizable or
+                NSWindowStyleMaskClosable or NSWindowStyleMaskResizable
+
+        window = NSWindow(windowRect, windowStyle, NSBackingStoreBuffered, false).apply {
+            title = "Окошко Konan"
+            opaque = true
+            hasShadow = true
+            preferredBackingLocation = NSWindowBackingLocationVideoMemory
+            hidesOnDeactivate = false
+            backgroundColor = NSColor.whiteColor()
+            releasedWhenClosed = false
+
+            delegate = object : NSObject(), NSWindowDelegateProtocol {
+                override fun windowShouldClose(sender: ObjCObject): Boolean {
+                    NSApplication.sharedApplication().stop(this)
+                    return true
+                }
+            }
+        }
+    }
+
+    override fun applicationWillFinishLaunching(notification: NSNotification) {
+        window.makeKeyAndOrderFront(this)
+    }
+}

samples/settings.gradle

@@ -12,4 +12,5 @@ include ':concurrent'
 // So temporary switching off for now, as it breaks the build 
 // of other samples if SDK is not present.
 //include ':androidNativeActivity'
+include ':objc'
 includeBuild '../'

shared/src/main/kotlin/org/jetbrains/kotlin/konan/target/ClangArgs.kt

@@ -43,13 +43,16 @@ class ClangTarget(val target: KonanTarget, konanProperties: KonanProperties) {
                         "-DUSE_GCC_UNWIND=1", "-DUSE_PE_COFF_SYMBOLS=1", "-DKONAN_WINDOWS=1")
 
             KonanTarget.MACBOOK ->
-                listOf("--sysroot=$sysRoot", "-mmacosx-version-min=10.11", "-DKONAN_OSX=1")
+                listOf("--sysroot=$sysRoot", "-mmacosx-version-min=10.11", "-DKONAN_OSX=1",
+                        "-DKONAN_OBJC_INTEROP=1")
 
             KonanTarget.IPHONE ->
-                listOf("-stdlib=libc++", "-arch", "arm64", "-isysroot", "$sysRoot", "-miphoneos-version-min=8.0.0")
+                listOf("-stdlib=libc++", "-arch", "arm64", "-isysroot", "$sysRoot", "-miphoneos-version-min=8.0.0",
+                        "-DKONAN_OBJC_INTEROP=1")
 
             KonanTarget.IPHONE_SIM ->
-                listOf("-stdlib=libc++", "-isysroot", "$sysRoot", "-miphoneos-version-min=8.0.0")
+                listOf("-stdlib=libc++", "-isysroot", "$sysRoot", "-miphoneos-version-min=8.0.0",
+                        "-DKONAN_OBJC_INTEROP=1")
 
             KonanTarget.ANDROID_ARM32 ->
                 listOf("-target", targetArg!!,