Add ObjCProtocol type to interop runtime

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

@@ -27,6 +27,8 @@ interface ObjCClass : ObjCObject
 interface ObjCClassOf<T : ObjCObject> : ObjCClass // TODO: T should be added to ObjCClass and all meta-classes instead.
 typealias ObjCObjectMeta = ObjCClass
 
+interface ObjCProtocol : ObjCObject
+
 @ExportTypeInfo("theForeignObjCObjectTypeInfo")
 @kotlin.native.internal.Frozen
 internal open class ForeignObjCObject : kotlin.native.internal.ObjCObjectWrapper

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

@@ -191,6 +191,7 @@ object KotlinTypes {
     val objCObjectMeta by InteropClassifier
     val objCClass by InteropClassifier
     val objCClassOf by InteropClassifier
+    val objCProtocol by InteropClassifier
 
     val cValuesRef by InteropClassifier
 

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

@@ -490,6 +490,11 @@ abstract class ObjCContainerStub(stubGenerator: StubGenerator,
             supers.add(classifier.type)
         }
 
+        if (!isMeta && container.isProtocolClass()) {
+            // TODO: map Protocol type to ObjCProtocol instead.
+            supers.add(KotlinTypes.objCProtocol.type)
+        }
+
         val keywords = when (container) {
             is ObjCClass -> "open class"
             is ObjCProtocol -> "interface"
@@ -690,3 +695,8 @@ private fun genProtocolGetter(
 
     return functionName
 }
+
+private fun ObjCClassOrProtocol.isProtocolClass(): Boolean = when (this) {
+    is ObjCClass -> (name == "Protocol" || binaryName == "Protocol")
+    is ObjCProtocol -> false
+}

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

@@ -31,6 +31,7 @@ import org.jetbrains.kotlin.types.typeUtil.supertypes
 internal val interopPackageName = InteropFqNames.packageName
 internal val objCObjectFqName = interopPackageName.child(Name.identifier("ObjCObject"))
 private val objCClassFqName = interopPackageName.child(Name.identifier("ObjCClass"))
+private val objCProtocolFqName = interopPackageName.child(Name.identifier("ObjCProtocol"))
 internal val externalObjCClassFqName = interopPackageName.child(Name.identifier("ExternalObjCClass"))
 private val objCMethodFqName = interopPackageName.child(Name.identifier("ObjCMethod"))
 private val objCConstructorFqName = FqName("kotlinx.cinterop.ObjCConstructor")
@@ -70,6 +71,12 @@ fun ClassDescriptor.isObjCMetaClass(): Boolean = this.getAllSuperClassifiers().a
     it.fqNameSafe == objCClassFqName
 }
 
+fun IrClass.isObjCProtocolClass(): Boolean =
+        this.fqNameSafe == objCProtocolFqName
+
+fun ClassDescriptor.isObjCProtocolClass(): Boolean =
+        this.fqNameSafe == objCProtocolFqName
+
 fun FunctionDescriptor.isObjCClassMethod() =
         this.containingDeclaration.let { it is ClassDescriptor && it.isObjCClass() }
 

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

@@ -9,7 +9,6 @@ package org.jetbrains.kotlin.backend.konan.llvm
 import kotlinx.cinterop.*
 import llvm.*
 import org.jetbrains.kotlin.backend.konan.*
-import org.jetbrains.kotlin.backend.konan.descriptors.isInterface
 import org.jetbrains.kotlin.backend.konan.llvm.objc.*
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.ir.declarations.*
@@ -17,6 +16,7 @@ import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.konan.target.*
 import org.jetbrains.kotlin.backend.konan.descriptors.resolveFakeOverride
 import org.jetbrains.kotlin.backend.konan.ir.*
+import org.jetbrains.kotlin.descriptors.konan.CompiledKonanModuleOrigin
 
 internal class CodeGenerator(override val context: Context) : ContextUtils {
 
@@ -832,12 +832,11 @@ internal class FunctionGenerationContext(val function: LLVMValueRef,
         assert(!irClass.isInterface)
 
         return if (irClass.isExternalObjCClass()) {
-            context.llvm.imports.add(irClass.llvmSymbolOrigin)
+            val llvmSymbolOrigin = irClass.llvmSymbolOrigin
 
             if (irClass.isObjCMetaClass()) {
                 val name = irClass.descriptor.getExternalObjCMetaClassBinaryName()
-
+                val objCClass = getObjCClass(name, llvmSymbolOrigin)
-                val objCClass = load(codegen.objCDataGenerator!!.genClassRef(name).llvm)
 
                 val getClass = context.llvm.externalFunction(
                         "object_getClass",
@@ -847,7 +846,7 @@ internal class FunctionGenerationContext(val function: LLVMValueRef,
 
                 call(getClass, listOf(objCClass), exceptionHandler = exceptionHandler)
             } else {
-                load(codegen.objCDataGenerator!!.genClassRef(irClass.descriptor.getExternalObjCClassBinaryName()).llvm)
+                getObjCClass(irClass.descriptor.getExternalObjCClassBinaryName(), llvmSymbolOrigin)
             }
         } else {
             if (irClass.isObjCMetaClass()) {
@@ -874,6 +873,11 @@ internal class FunctionGenerationContext(val function: LLVMValueRef,
         }
     }
 
+    fun getObjCClass(binaryName: String, llvmSymbolOrigin: CompiledKonanModuleOrigin): LLVMValueRef {
+        context.llvm.imports.add(llvmSymbolOrigin)
+        return load(codegen.objCDataGenerator!!.genClassRef(binaryName).llvm)
+    }
+
     fun resetDebugLocation() {
         if (!context.shouldContainDebugInfo()) return
         currentPositionHolder.resetBuilderDebugLocation()

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

@@ -1403,6 +1403,15 @@ internal class CodeGeneratorVisitor(val context: Context, val lifetimes: Map<IrE
                 call(isClass, listOf(objCObject)).let {
                     functionGenerationContext.icmpNe(it, Int8(0).llvm)
                 }
+            } else if (dstClass.isObjCProtocolClass()) {
+                // Note: it is not clear whether this class should be looked up this way.
+                // clang does the same, however swiftc uses dynamic lookup.
+                val protocolClass =
+                        functionGenerationContext.getObjCClass("Protocol", context.standardLlvmSymbolsOrigin)
+                call(
+                        context.llvm.Kotlin_Interop_IsObjectKindOfClass,
+                        listOf(objCObject, protocolClass)
+                )
             } else {
                 kTrue
             }

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

@@ -801,16 +801,15 @@ internal class ObjCExportTranslatorImpl(
         // TODO: more precise types can be used.
 
         if (descriptor.isObjCMetaClass()) return ObjCMetaClassType
+        if (descriptor.isObjCProtocolClass()) return foreignClassType("Protocol")
 
         if (descriptor.isExternalObjCClass() || descriptor.isObjCForwardDeclaration()) {
             return if (descriptor.isInterface) {
                 val name = descriptor.name.asString().removeSuffix("Protocol")
-                generator?.referenceProtocol(name)
+                foreignProtocolType(name)
-                ObjCProtocolType(name)
             } else {
                 val name = descriptor.name.asString()
-                generator?.referenceClass(name)
+                foreignClassType(name)
-                ObjCClassType(name)
             }
         }
 
@@ -821,6 +820,16 @@ internal class ObjCExportTranslatorImpl(
         return ObjCIdType
     }
 
+    private fun foreignProtocolType(name: String): ObjCProtocolType {
+        generator?.referenceProtocol(name)
+        return ObjCProtocolType(name)
+    }
+
+    private fun foreignClassType(name: String): ObjCClassType {
+        generator?.referenceClass(name)
+        return ObjCClassType(name)
+    }
+
     internal fun mapFunctionTypeIgnoringNullability(
             functionType: KotlinType,
             objCExportScope: ObjCExportScope,

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

@@ -205,3 +205,11 @@ NSObject* createNSObject() {
 -(int)hashCode:(int)p;
 -(BOOL)equals;
 @end;
+
+id getPrinterProtocolRaw() {
+  return @protocol(Printer);
+}
+
+Protocol* getPrinterProtocol() {
+  return @protocol(Printer);
+}

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

@@ -151,6 +151,11 @@ fun testTypeOps() {
     assertTrue(NSObject.asAny() is ObjCClass)
     assertTrue(NSObject.asAny() is ObjCClassOf<*>)
 
+    assertFalse(Any() is ObjCProtocol)
+    assertTrue(getPrinterProtocolRaw() is ObjCProtocol)
+    val printerProtocol = getPrinterProtocol()!!
+    assertTrue(printerProtocol.asAny() is ObjCProtocol)
+
     assertEquals(3u, ("foo" as NSString).length())
     assertEquals(4u, ((1..4).joinToString("") as NSString).length())
     assertEquals(2u, (listOf(0, 1) as NSArray).count())