Introduce kotlin.jvm.internal.Lambda, superclass for all lambdas

It has its arity precomputed, as opposed to the future KFunctionImpl inheriting
from FunctionImpl, for which the computation of arity can take some time and so
it shouldn't be passed in the constructor and saved as a field

compiler/backend/src/org/jetbrains/kotlin/codegen/ClosureCodegen.java

@@ -35,6 +35,7 @@ import org.jetbrains.kotlin.load.java.JvmAbi;
 import org.jetbrains.kotlin.psi.JetElement;
 import org.jetbrains.kotlin.resolve.BindingContext;
 import org.jetbrains.kotlin.resolve.DescriptorUtils;
+import org.jetbrains.kotlin.resolve.jvm.AsmTypes;
 import org.jetbrains.kotlin.types.JetType;
 import org.jetbrains.kotlin.types.expressions.OperatorConventions;
 import org.jetbrains.org.objectweb.asm.MethodVisitor;
@@ -306,7 +307,14 @@ public class ClosureCodegen extends MemberCodegen<JetElement> {
             }
 
             iv.load(0, superClassAsmType);
-            iv.invokespecial(superClassAsmType.getInternalName(), "<init>", "()V", false);
+
+            if (superClassAsmType.equals(AsmTypes.LAMBDA)) {
+                iv.iconst(funDescriptor.getValueParameters().size());
+                iv.invokespecial(superClassAsmType.getInternalName(), "<init>", "(I)V", false);
+            }
+            else {
+                iv.invokespecial(superClassAsmType.getInternalName(), "<init>", "()V", false);
+            }
 
             iv.visitInsn(RETURN);
 

compiler/backend/src/org/jetbrains/kotlin/codegen/JvmRuntimeTypes.java

@@ -39,6 +39,7 @@ import static org.jetbrains.kotlin.resolve.descriptorUtil.DescriptorUtilPackage.
 public class JvmRuntimeTypes {
     private final ReflectionTypes reflectionTypes;
 
+    private final ClassDescriptor lambda;
     private final ClassDescriptor functionImpl;
     private final ClassDescriptor memberFunctionImpl;
     private final ClassDescriptor extensionFunctionImpl;
@@ -53,6 +54,7 @@ public class JvmRuntimeTypes {
         );
         PackageFragmentDescriptor kotlinJvmInternal = new MutablePackageFragmentDescriptor(module, new FqName("kotlin.jvm.internal"));
 
+        this.lambda = createClass(kotlinJvmInternal, "Lambda");
         this.functionImpl = createClass(kotlinJvmInternal, "FunctionImpl");
         this.memberFunctionImpl = createClass(kotlinJvmInternal, "MemberFunctionImpl");
         this.extensionFunctionImpl = createClass(kotlinJvmInternal, "ExtensionFunctionImpl");
@@ -76,8 +78,6 @@ public class JvmRuntimeTypes {
     public Collection<JetType> getSupertypesForClosure(@NotNull FunctionDescriptor descriptor) {
         ReceiverParameterDescriptor receiverParameter = descriptor.getExtensionReceiverParameter();
 
-        ClassDescriptor functionImplClass = receiverParameter != null ? extensionFunctionImpl : functionImpl;
-
         //noinspection ConstantConditions
         JetType functionType = getBuiltIns(descriptor).getFunctionType(
                 Annotations.EMPTY,
@@ -86,7 +86,7 @@ public class JvmRuntimeTypes {
                 descriptor.getReturnType()
         );
 
-        return Arrays.asList(functionImplClass.getDefaultType(), functionType);
+        return Arrays.asList(lambda.getDefaultType(), functionType);
     }
 
     @NotNull

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/AsmTypes.java

@@ -34,6 +34,8 @@ public class AsmTypes {
     public static final Type PROPERTY_METADATA_TYPE = Type.getObjectType("kotlin/PropertyMetadata");
     public static final Type PROPERTY_METADATA_IMPL_TYPE = Type.getObjectType("kotlin/PropertyMetadataImpl");
 
+    public static final Type LAMBDA = Type.getObjectType("kotlin/jvm/internal/Lambda");
+
     public static final Type K_CLASS_TYPE = reflect("KClass");
     public static final Type K_CLASS_ARRAY_TYPE = Type.getObjectType("[" + K_CLASS_TYPE.getDescriptor());
     public static final Type K_PACKAGE_TYPE = reflect("KPackage");

core/reflection.jvm/src/kotlin/reflect/jvm/internal/KFunctionImpl.kt

@@ -21,4 +21,4 @@ import kotlin.jvm.internal.FunctionImpl
 /**
  * @suppress
  */
-public abstract class KFunctionImpl<out R> : FunctionImpl<R>()
+public abstract class KFunctionImpl<out R> : FunctionImpl()

core/runtime.jvm/src/kotlin/jvm/internal/Lambda.kt

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2010-2015 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 kotlin.jvm.internal
+
+public abstract class Lambda(private val arity: Int) : FunctionImpl() {
+    override fun getArity() = arity
+
+    override fun toString() = "${(this as Object).getClass().getGenericInterfaces()[0]}"
+}