Support classes with more than 32 serializable properties

Via increasing count of int bit masks in synthetic constructor

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/common/SerializerCodegen.kt

@@ -33,7 +33,7 @@ abstract class SerializerCodegen(
     val serializableDescriptor: ClassDescriptor = getSerializableClassDescriptorBySerializer(serializerDescriptor)!!
     protected val serialName: String = serializableDescriptor.annotations.serialNameValue ?: serializableDescriptor.fqNameUnsafe.asString()
     protected val properties = SerializableProperties(serializableDescriptor, bindingContext)
-    protected val orderedProperties = properties.serializableProperties
+    protected val serializableProperties = properties.serializableProperties
 
     private fun checkSerializability() {
         check(properties.isExternallySerializable) {

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/SerializableIrGenerator.kt

@@ -19,11 +19,8 @@ import org.jetbrains.kotlin.resolve.descriptorUtil.getSuperClassOrAny
 import org.jetbrains.kotlin.resolve.descriptorUtil.module
 import org.jetbrains.kotlin.util.OperatorNameConventions
 import org.jetbrains.kotlinx.serialization.compiler.backend.common.SerializableCodegen
+import org.jetbrains.kotlinx.serialization.compiler.resolve.*
 import org.jetbrains.kotlinx.serialization.compiler.resolve.SerialEntityNames.MISSING_FIELD_EXC
-import org.jetbrains.kotlinx.serialization.compiler.resolve.getClassFromSerializationPackage
-import org.jetbrains.kotlinx.serialization.compiler.resolve.hasCompanionObjectAsSerializer
-import org.jetbrains.kotlinx.serialization.compiler.resolve.hasSerializableAnnotationWithoutArgs
-import org.jetbrains.kotlinx.serialization.compiler.resolve.isInternalSerializable
 
 class SerializableIrGenerator(
     val irClass: IrClass,
@@ -51,10 +48,11 @@ class SerializableIrGenerator(
                 generateAnySuperConstructorCall(toBuilder = this@contributeConstructor)
             else
                 TODO("Serializable classes with inheritance")
-            val seenVar = ctor.valueParameters[0]
+            val seenVarsOffset = properties.serializableProperties.bitMaskSlotCount()
+            val seenVars = (0 until seenVarsOffset).map { ctor.valueParameters[it] }
 
             for ((index, prop) in properties.serializableProperties.withIndex()) {
-                val paramRef = ctor.valueParameters[index + 1]
+                val paramRef = ctor.valueParameters[index + seenVarsOffset]
                 // assign this.a = a in else branch
                 val assignParamExpr = irSetField(irGet(thiz), prop.irField, irGet(paramRef))
 
@@ -69,7 +67,11 @@ class SerializableIrGenerator(
                 val propNotSeenTest =
                     irEquals(
                         irInt(0),
-                        irBinOp(OperatorNameConventions.AND, irGet(seenVar), irInt(1 shl (index % 32)))
+                        irBinOp(
+                            OperatorNameConventions.AND,
+                            irGet(seenVars[bitMaskSlotAt(index)]),
+                            irInt(1 shl (index % 32))
+                        )
                     )
 
                 +irIfThenElse(compilerContext.irBuiltIns.unitType, propNotSeenTest, ifNotSeenExpr, assignParamExpr)

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/SerializerIrGenerator.kt

@@ -95,7 +95,7 @@ class SerializerIrGenerator(val irClass: IrClass, override val compilerContext:
                             dispatchReceiver = irGet(localDesc)
                         }.mapValueParameters { irString(fieldName) }
 
-                    for (classProp in orderedProperties) {
+                    for (classProp in serializableProperties) {
                         if (classProp.transient) continue
                         +addFieldCall(classProp.name)
                         // add property annotations
@@ -163,7 +163,7 @@ class SerializerIrGenerator(val irClass: IrClass, override val compilerContext:
         }
 
     override fun generateChildSerializersGetter(function: FunctionDescriptor) = irClass.contributeFunction(function) { irFun ->
-        val allSerializers = orderedProperties.map { requireNotNull(
+        val allSerializers = serializableProperties.map { requireNotNull(
                 serializerTower(this@SerializerIrGenerator, it)) { "Property ${it.name} must have a serializer" }
         }
 
@@ -214,7 +214,7 @@ class SerializerIrGenerator(val irClass: IrClass, override val compilerContext:
         fun SerializableProperty.irGet(): IrGetField = irGetField(irGet(serialObjectSymbol), irField)
 
         //  internal serialization via virtual calls?
-        for ((index, property) in orderedProperties.filter { !it.transient }.withIndex()) {
+        for ((index, property) in serializableProperties.filter { !it.transient }.withIndex()) {
             // output.writeXxxElementValue(classDesc, index, value)
             val sti = getSerialTypeInfo(property)
             val innerSerial = serializerInstance(
@@ -252,7 +252,7 @@ class SerializerIrGenerator(val irClass: IrClass, override val compilerContext:
                 // if (obj.prop != DEFAULT_VALUE || output.shouldEncodeElementDefault(this.descriptor, i))
                 //    output.encodeIntElement(this.descriptor, i, obj.prop)
                 val shouldEncodeFunc = kOutputClass.referenceMethod(CallingConventions.shouldEncodeDefault)
-                val partA = irNotEquals(property.irGet(), fieldInitializer(property)!!) // todo: props w/o backing fields
+                val partA = irNotEquals(property.irGet(), fieldInitializer(property)!!)
                 val partB = irInvoke(irGet(localOutput), shouldEncodeFunc, irGet(localSerialDesc), irInt(index))
                 // Ir infrastructure does not have dedicated symbol for ||, so
                 //  `a || b == if (a) true else b`, see org.jetbrains.kotlin.ir.builders.PrimitivesKt.oror
@@ -305,12 +305,12 @@ class SerializerIrGenerator(val irClass: IrClass, override val compilerContext:
 //        val readAll = irTemporaryVar(irBoolean(false), "readAll", parent = loadFunc)
 //
         // calculating bit mask vars
-        val blocksCnt = orderedProperties.size / 32 + 1
+        val blocksCnt = serializableProperties.bitMaskSlotCount()
 
         // var bitMask0 = 0, bitMask1 = 0...
         val bitMasks = (0 until blocksCnt).map { irTemporaryVar(irInt(0), "bitMask$it") }
         // var local0 = null, local1 = null ...
-        val localProps = orderedProperties.mapIndexed { i, prop ->
+        val localProps = serializableProperties.mapIndexed { i, prop ->
             val (expr, type) = defaultValueAndType(prop)
             irTemporaryVar(
                 expr,
@@ -341,7 +341,7 @@ class SerializerIrGenerator(val irClass: IrClass, override val compilerContext:
                     // if index == -1 (READ_DONE) break loop
                     +IrBranchImpl(irEquals(indexVar.get(), irInt(-1)), irSetVar(flagVar.symbol, irBoolean(false)))
 
-                    val branchBodies: List<Pair<Int, IrExpression>> = orderedProperties.mapIndexed { index, property ->
+                    val branchBodies: List<Pair<Int, IrExpression>> = serializableProperties.mapIndexed { index, property ->
                         val body = irBlock {
                             val sti = getSerialTypeInfo(property)
                             val innerSerial = serializerInstance(this@SerializerIrGenerator, serializableDescriptor, sti.serializer, property.module, property.type, property.genericIndex)
@@ -398,7 +398,7 @@ class SerializerIrGenerator(val irClass: IrClass, override val compilerContext:
         val ctor: IrConstructorSymbol = if (serializableDescriptor.isInternalSerializable) {
             val ctorDesc = serializableIrClass
                 .constructors.single { it.origin == SERIALIZABLE_PLUGIN_ORIGIN }
-            args = listOf(irGet(bitMasks[0])) + args + irNull()
+            args = bitMasks.map { irGet(it) } + args + irNull()
             ctorDesc.symbol
         } else {
             compilerContext.externalSymbols.referenceConstructor(serializableDescriptor.unsubstitutedPrimaryConstructor!!)

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/js/SerializableJsTranslator.kt

@@ -32,16 +32,12 @@ import org.jetbrains.kotlin.psi.KtExpression
 import org.jetbrains.kotlin.psi.KtPureClassOrObject
 import org.jetbrains.kotlinx.serialization.compiler.backend.common.SerializableCodegen
 import org.jetbrains.kotlinx.serialization.compiler.backend.common.anonymousInitializers
+import org.jetbrains.kotlinx.serialization.compiler.resolve.*
 import org.jetbrains.kotlinx.serialization.compiler.resolve.SerialEntityNames.MISSING_FIELD_EXC
-import org.jetbrains.kotlinx.serialization.compiler.resolve.getClassFromSerializationPackage
-import org.jetbrains.kotlinx.serialization.compiler.resolve.hasCompanionObjectAsSerializer
-import org.jetbrains.kotlinx.serialization.compiler.resolve.hasSerializableAnnotationWithoutArgs
-import org.jetbrains.kotlinx.serialization.compiler.resolve.isInternalSerializable
 
 class SerializableJsTranslator(
     val declaration: KtPureClassOrObject,
     val descriptor: ClassDescriptor,
-    val translator: DeclarationBodyVisitor,
     val context: TranslationContext
 ) : SerializableCodegen(descriptor, context.bindingContext()) {
 
@@ -63,9 +59,10 @@ class SerializableJsTranslator(
                     Namer.createObjectWithPrototypeFrom(context.getInnerNameForDescriptor(serializableDescriptor).makeRef())
                 )
             )
-            val seenVar = jsFun.parameters[0].name.makeRef()
+            val seenVarsOffset = properties.serializableProperties.bitMaskSlotCount()
+            val seenVars = (0 until seenVarsOffset).map { jsFun.parameters[it].name.makeRef() }
             for ((index, prop) in properties.serializableProperties.withIndex()) {
-                val paramRef = jsFun.parameters[index + 1].name.makeRef()
+                val paramRef = jsFun.parameters[index + seenVarsOffset].name.makeRef()
                 // assign this.a = a in else branch
                 val assignParamStmt = TranslationUtils.assignmentToBackingField(context, prop.descriptor, paramRef).makeStmt()
 
@@ -77,7 +74,7 @@ class SerializableJsTranslator(
                     JsThrow(JsNew(missingExceptionClassRef, listOf(JsStringLiteral(prop.name))))
                 }
                 // (seen & 1 << i == 0) -- not seen
-                val notSeenTest = propNotSeenTest(seenVar, index)
+                val notSeenTest = propNotSeenTest(seenVars[bitMaskSlotAt(index)], index)
                 +JsIf(notSeenTest, ifNotSeenStmt, assignParamStmt)
             }
 
@@ -111,7 +108,7 @@ class SerializableJsTranslator(
             context: TranslationContext
         ) {
             if (serializableClass.isInternalSerializable)
-                SerializableJsTranslator(declaration, serializableClass, translator, context).generate()
+                SerializableJsTranslator(declaration, serializableClass, context).generate()
             else if (serializableClass.hasSerializableAnnotationWithoutArgs && !serializableClass.hasCompanionObjectAsSerializer) {
                 throw CompilationException(
                     "@Serializable annotation on $serializableClass would be ignored because it is impossible to serialize it automatically. " +

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/js/SerializerJsTranslator.kt

@@ -72,7 +72,7 @@ class SerializerJsTranslator(descriptor: ClassDescriptor,
         val pushClassFunc = serialDescImplClass.getFuncDesc(CallingConventions.addClassAnnotation).single()
         val serialClassDescRef = JsNameRef(context.getNameForDescriptor(generatedSerialDescPropertyDescriptor), JsThisRef())
 
-        for (prop in orderedProperties) {
+        for (prop in serializableProperties) {
             if (prop.transient) continue
             val call = JsInvocation(
                 JsNameRef(context.getNameForDescriptor(addFunc), serialClassDescRef),
@@ -100,7 +100,7 @@ class SerializerJsTranslator(descriptor: ClassDescriptor,
     }
 
     override fun generateChildSerializersGetter(function: FunctionDescriptor) = generateFunction(function) { _, _ ->
-        val allSerializers = orderedProperties.map { requireNotNull(serializerTower(it)) { "Property ${it.name} must have a serializer" } }
+        val allSerializers = serializableProperties.map { requireNotNull(serializerTower(it)) { "Property ${it.name} must have a serializer" } }
         +JsReturn(JsArrayLiteral(allSerializers))
     }
 
@@ -160,7 +160,7 @@ class SerializerJsTranslator(descriptor: ClassDescriptor,
         fun SerializableProperty.jsNameRef() = JsNameRef(ctx.getNameForDescriptor(descriptor), objRef)
 
         // todo: internal serialization via virtual calls
-        val labeledProperties = orderedProperties.filter { !it.transient }
+        val labeledProperties = serializableProperties.filter { !it.transient }
         for (index in labeledProperties.indices) {
             val property = labeledProperties[index]
             if (property.transient) continue
@@ -224,15 +224,15 @@ class SerializerJsTranslator(descriptor: ClassDescriptor,
         +JsVars(JsVars.JsVar(indexVar.name), JsVars.JsVar(readAllVar.name, JsBooleanLiteral(false)))
 
         // calculating bit mask vars
-        val blocksCnt = orderedProperties.size / 32 + 1
+        val blocksCnt = serializableProperties.bitMaskSlotCount()
-        fun bitMaskOff(i: Int) = i / 32
+        fun bitMaskOff(i: Int) = bitMaskSlotAt(i)
 
         // var bitMask0 = 0, bitMask1 = 0...
         val bitMasks = (0 until blocksCnt).map { JsNameRef(jsFun.scope.declareFreshName("bitMask$it")) }
         +JsVars(bitMasks.map { JsVars.JsVar(it.name, JsIntLiteral(0)) }, false)
 
         // var localProp0, localProp1, ...
-        val localProps = orderedProperties.mapIndexed {i, _ -> JsNameRef(jsFun.scope.declareFreshName("local$i")) }
+        val localProps = serializableProperties.mapIndexed { i, _ -> JsNameRef(jsFun.scope.declareFreshName("local$i")) }
         +JsVars(localProps.map { JsVars.JsVar(it.name) }, true)
 
         //input = input.readBegin(...)
@@ -241,8 +241,10 @@ class SerializerJsTranslator(descriptor: ClassDescriptor,
         }
         val inputVar = JsNameRef(jsFun.scope.declareFreshName("input"))
         val readBeginF = decoderClass.getFuncDesc(CallingConventions.begin).single()
-        val readBeginCall = JsInvocation(JsNameRef(context.getNameForDescriptor(readBeginF), JsNameRef(jsFun.parameters[0].name)),
+        val readBeginCall = JsInvocation(
-                                         serialClassDescRef, JsArrayLiteral(typeParams))
+            JsNameRef(context.getNameForDescriptor(readBeginF), JsNameRef(jsFun.parameters[0].name)),
+            serialClassDescRef, JsArrayLiteral(typeParams)
+        )
         +JsVars(JsVars.JsVar(inputVar.name, readBeginCall))
 
         // while(true) {
@@ -265,7 +267,7 @@ class SerializerJsTranslator(descriptor: ClassDescriptor,
                     ).makeStmt()
                 }
                 // all properties
-                for ((i, property) in orderedProperties.withIndex()) {
+                for ((i, property) in serializableProperties.withIndex()) {
                     case(JsIntLiteral(i)) {
                         // input.readXxxElementValue
                         val sti = getSerialTypeInfo(property)
@@ -278,26 +280,33 @@ class SerializerJsTranslator(descriptor: ClassDescriptor,
                                     .single { !unknownSer || (it.valueParameters.size == 3) }
                                     .let { context.getNameForDescriptor(it) }
                             val readArgs = mutableListOf(serialClassDescRef, JsIntLiteral(i))
-                            if (unknownSer) readArgs.add(ExpressionVisitor.getObjectKClass(
+                            if (unknownSer) readArgs.add(
+                                ExpressionVisitor.getObjectKClass(
                                     this@SerializerJsTranslator.context,
                                     property.type.toClassDescriptor!!
-                            ))
+                                )
+                            )
                             JsInvocation(JsNameRef(readFunc, inputVar), readArgs)
-                        }
+                        } else {
-                        else {
+                            val notSeenTest = propNotSeenTest(bitMasks[bitMaskOff(i)], i)
-                            val notSeenTest = propNotSeenTest(bitMasks[i / 32], i)
                             val readFunc =
-                                    inputClass.getFuncDesc("${CallingConventions.decode}${sti.elementMethodPrefix}Serializable${CallingConventions.elementPostfix}").single()
+                                inputClass.getFuncDesc("${CallingConventions.decode}${sti.elementMethodPrefix}Serializable${CallingConventions.elementPostfix}")
+                                    .single()
                                     .let { context.getNameForDescriptor(it) }
                             val updateFunc =
-                                    inputClass.getFuncDesc("${CallingConventions.update}${sti.elementMethodPrefix}Serializable${CallingConventions.elementPostfix}").single()
+                                inputClass.getFuncDesc("${CallingConventions.update}${sti.elementMethodPrefix}Serializable${CallingConventions.elementPostfix}")
+                                    .single()
                                     .let { context.getNameForDescriptor(it) }
-                            JsConditional(notSeenTest,
+                            JsConditional(
-                                          JsInvocation(JsNameRef(readFunc, inputVar),
+                                notSeenTest,
+                                JsInvocation(
+                                    JsNameRef(readFunc, inputVar),
                                     serialClassDescRef,
                                     JsIntLiteral(i),
-                                                       innerSerial),
+                                    innerSerial
-                                          JsInvocation(JsNameRef(updateFunc, inputVar),
+                                ),
+                                JsInvocation(
+                                    JsNameRef(updateFunc, inputVar),
                                     serialClassDescRef,
                                     JsIntLiteral(i),
                                     innerSerial,
@@ -328,8 +337,9 @@ class SerializerJsTranslator(descriptor: ClassDescriptor,
 
                         // bitMask[i] |= 1 << x
                         val bitPos = 1 shl (i % 32)
-                        +JsBinaryOperation(JsBinaryOperator.ASG_BIT_OR,
+                        +JsBinaryOperation(
-                                           bitMasks[i / 32],
+                            JsBinaryOperator.ASG_BIT_OR,
+                            bitMasks[bitMaskOff(i)],
                             JsIntLiteral(bitPos)
                         ).makeStmt()
                         // if (!readAll) break
@@ -361,7 +371,7 @@ class SerializerJsTranslator(descriptor: ClassDescriptor,
         // todo: external deserialization with primary constructor and setters calls after resolution of KT-11586
         val constrDesc = KSerializerDescriptorResolver.createLoadConstructorDescriptor(serializableDescriptor, context.bindingContext())
         val constrRef = context.getInnerNameForDescriptor(constrDesc).makeRef()
-        val args: MutableList<JsExpression> = mutableListOf(bitMasks[0])
+        val args: MutableList<JsExpression> = bitMasks.toMutableList()
         args += localProps
         args += JsNullLiteral()
         +JsReturn(JsInvocation(constrRef, args))

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/jvm/JVMCodegenUtil.kt

@@ -120,9 +120,17 @@ fun InstructionAdapter.genKOutputMethodCall(
     )
 }
 
-internal fun InstructionAdapter.buildInternalConstructorDesc(propsStartVar: Int, bitMaskBase: Int, codegen: ClassBodyCodegen, args: List<SerializableProperty>): String {
+internal fun InstructionAdapter.buildInternalConstructorDesc(
-    val constructorDesc = StringBuilder("(I")
+    propsStartVar: Int,
-    load(bitMaskBase, OPT_MASK_TYPE)
+    bitMaskBase: Int,
+    codegen: ClassBodyCodegen,
+    args: List<SerializableProperty>
+): String {
+    val constructorDesc = StringBuilder("(")
+    repeat(args.bitMaskSlotCount()) {
+        constructorDesc.append("I")
+        load(bitMaskBase + it, Type.INT_TYPE)
+    }
     var propVar = propsStartVar
     for (property in args) {
         val propertyType = codegen.typeMapper.mapType(property.type)
@@ -135,8 +143,10 @@ internal fun InstructionAdapter.buildInternalConstructorDesc(propsStartVar: Int,
     return constructorDesc.toString()
 }
 
-internal fun ImplementationBodyCodegen.generateMethod(function: FunctionDescriptor,
+internal fun ImplementationBodyCodegen.generateMethod(
-                                                      block: InstructionAdapter.(JvmMethodSignature, ExpressionCodegen) -> Unit) {
+    function: FunctionDescriptor,
+    block: InstructionAdapter.(JvmMethodSignature, ExpressionCodegen) -> Unit
+) {
     this.functionCodegen.generateMethod(OtherOrigin(this.myClass.psiOrParent, function), function,
                                         object : FunctionGenerationStrategy.CodegenBased(this.state) {
                                             override fun doGenerateBody(codegen: ExpressionCodegen, signature: JvmMethodSignature) {

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/jvm/SerializableCodegenImpl.kt

@@ -178,13 +178,15 @@ class SerializableCodegenImpl(
 
     private fun InstructionAdapter.doGenerateConstructorImpl(exprCodegen: ExpressionCodegen) {
         val seenMask = 1
-        var (propIndex, propOffset) = generateSuperSerializableCall(2)
+        val bitMaskOff = fun(it: Int): Int { return seenMask + bitMaskSlotAt(it) }
+        val bitMaskEnd = seenMask + properties.serializableProperties.bitMaskSlotCount()
+        var (propIndex, propOffset) = generateSuperSerializableCall(bitMaskEnd)
         for (i in propIndex until properties.serializableProperties.size) {
             val prop = properties[i]
             val propType = prop.asmType
             if (!prop.optional) {
                 // primary were validated before constructor call
-                genValidateProperty(i) { seenMask }
+                genValidateProperty(i, bitMaskOff)
                 val nonThrowLabel = Label()
                 ificmpne(nonThrowLabel)
                 genExceptionThrow(serializationExceptionMissingFieldName, prop.name)
@@ -194,12 +196,11 @@ class SerializableCodegenImpl(
                 load(propOffset, propType)
                 putfield(thisAsmType.internalName, prop.descriptor.name.asString(), propType.descriptor)
             } else {
-                genValidateProperty(i) { seenMask }
+                genValidateProperty(i, bitMaskOff)
                 val setLbl = Label()
                 val nextLabel = Label()
                 ificmpeq(setLbl)
                 // setting field
-                // todo: validate nullability
                 load(0, thisAsmType)
                 load(propOffset, propType)
                 putfield(thisAsmType.internalName, prop.descriptor.name.asString(), propType.descriptor)
@@ -228,7 +229,7 @@ class SerializableCodegenImpl(
             .forEach { (t, u) -> exprCodegen.genInitParam(t, u) }
 
         // init blocks
-        // todo: proper order with other initializers
+        // todo: proper order with other initializers?
         classCodegen.myClass.anonymousInitializers()
             .forEach { exprCodegen.gen(it, Type.VOID_TYPE) }
         areturn(Type.VOID_TYPE)

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/jvm/SerializerCodegenImpl.kt

@@ -89,7 +89,7 @@ class SerializerCodegenImpl(
         }
         invokespecial(descImplType.internalName, "<init>", "(Ljava/lang/String;${generatedSerializerType.descriptor})V", false)
         store(descriptorVar, descImplType)
-        for (property in orderedProperties) {
+        for (property in serializableProperties) {
             if (property.transient) continue
             load(descriptorVar, descImplType)
             aconst(property.name)
@@ -187,13 +187,13 @@ class SerializerCodegenImpl(
 
     override fun generateChildSerializersGetter(function: FunctionDescriptor) {
         codegen.generateMethod(function) { _, _ ->
-            val size = orderedProperties.size
+            val size = serializableProperties.size
             iconst(size)
             newarray(kSerializerType)
             for (i in 0 until size) {
                 dup() // array
                 iconst(i) // index
-                val prop = orderedProperties[i]
+                val prop = serializableProperties[i]
                 assert(
                     stackValueSerializerInstanceFromSerializerWithoutSti(
                         codegen,
@@ -224,7 +224,8 @@ class SerializerCodegenImpl(
             invokeinterface(
                 encoderType.internalName, CallingConventions.begin,
                 "(" + descType.descriptor + kSerializerArrayType.descriptor +
-                          ")" + kOutputType.descriptor)
+                        ")" + kOutputType.descriptor
+            )
             store(outputVar, kOutputType)
             if (serializableDescriptor.isInternalSerializable) {
                 val sig = StringBuilder("(${kOutputType.descriptor}${descType.descriptor}")
@@ -240,11 +241,11 @@ class SerializerCodegenImpl(
                 sig.append(")V")
                 invokevirtual(
                     objType.internalName, SerialEntityNames.WRITE_SELF_NAME.asString(),
-                              sig.toString(), false)
+                    sig.toString(), false
-            }
+                )
-            else {
+            } else {
                 // loop for all properties
-                val labeledProperties = orderedProperties.filter { !it.transient }
+                val labeledProperties = serializableProperties.filter { !it.transient }
                 for (index in labeledProperties.indices) {
                     val property = labeledProperties[index]
                     if (property.transient) continue
@@ -260,7 +261,8 @@ class SerializerCodegenImpl(
             load(descVar, descType)
             invokeinterface(
                 kOutputType.internalName, CallingConventions.end,
-                          "(" + descType.descriptor + ")V")
+                "(" + descType.descriptor + ")V"
+            )
             // return
             areturn(Type.VOID_TYPE)
         }
@@ -289,9 +291,9 @@ class SerializerCodegenImpl(
             val indexVar = 3
             val readAllVar = 4
             val bitMaskBase = 5
-            val blocksCnt = orderedProperties.size / OPT_MASK_BITS + 1
+            val blocksCnt = serializableProperties.bitMaskSlotCount()
-            fun bitMaskOff(i: Int) = bitMaskBase + (i / OPT_MASK_BITS) * OPT_MASK_TYPE.size
+            val bitMaskOff = fun(it: Int): Int { return bitMaskBase + bitMaskSlotAt(it) }
-            val propsStartVar = bitMaskBase + OPT_MASK_TYPE.size * blocksCnt
+            val propsStartVar = bitMaskBase + blocksCnt
             stackSerialClassDesc(descVar)
             // boolean readAll = false
             iconst(0)
@@ -304,7 +306,7 @@ class SerializerCodegenImpl(
             }
             // initialize all prop vars
             var propVar = propsStartVar
-            for (property in orderedProperties) {
+            for (property in serializableProperties) {
                 val propertyType = codegen.typeMapper.mapType(property.type)
                 stackValueDefault(propertyType)
                 store(propVar, propertyType)
@@ -317,7 +319,8 @@ class SerializerCodegenImpl(
             invokeinterface(
                 decoderType.internalName, CallingConventions.begin,
                 "(" + descType.descriptor + kSerializerArrayType.descriptor +
-                          ")" + kInputType.descriptor)
+                        ")" + kInputType.descriptor
+            )
             store(inputVar, kInputType)
             // readElement: int index = input.readElement(classDesc)
             val readElementLabel = Label()
@@ -326,10 +329,11 @@ class SerializerCodegenImpl(
             load(descVar, descType)
             invokeinterface(
                 kInputType.internalName, CallingConventions.decodeElementIndex,
-                          "(" + descType.descriptor + ")I")
+                "(" + descType.descriptor + ")I"
+            )
             store(indexVar, Type.INT_TYPE)
             // switch(index)
-            val labeledProperties = orderedProperties.filter { !it.transient }
+            val labeledProperties = serializableProperties.filter { !it.transient }
             val readAllLabel = Label()
             val readEndLabel = Label()
             val incorrectIndLabel = Label()
@@ -348,7 +352,7 @@ class SerializerCodegenImpl(
             // loop for all properties
             propVar = propsStartVar
             var labelNum = 0
-            for ((index, property) in orderedProperties.withIndex()) {
+            for ((index, property) in serializableProperties.withIndex()) {
                 val propertyType = codegen.typeMapper.mapType(property.type)
                 if (!property.transient) {
                     // labelI:
@@ -382,7 +386,7 @@ class SerializerCodegenImpl(
                         // we can choose either it is read or update
                         val readLabel = Label()
                         val endL = Label()
-                        genValidateProperty(index, ::bitMaskOff)
+                        genValidateProperty(index, bitMaskOff)
                         ificmpeq(readLabel)
                         load(propVar, propertyType)
                         StackValue.coerce(propertyType, sti.type, this)
@@ -398,8 +402,7 @@ class SerializerCodegenImpl(
 
                     if (sti.unit) {
                         StackValue.putUnitInstance(this)
-                    }
+                    } else {
-                    else {
                         StackValue.coerce(sti.type, propertyType, this)
                     }
                     store(propVar, propertyType)
@@ -425,8 +428,10 @@ class SerializerCodegenImpl(
             visitLabel(readEndLabel)
             load(inputVar, kInputType)
             load(descVar, descType)
-            invokeinterface(kInputType.internalName, CallingConventions.end,
+            invokeinterface(
-                          "(" + descType.descriptor + ")V")
+                kInputType.internalName, CallingConventions.end,
+                "(" + descType.descriptor + ")V"
+            )
             if (!serializableDescriptor.isInternalSerializable) {
                 //validate all required (constructor) fields
                 val nonThrowLabel = Label()
@@ -435,10 +440,13 @@ class SerializerCodegenImpl(
                     if (property.optional || property.transient) {
                         // todo: Normal reporting of error
                         if (!property.isConstructorParameterWithDefault)
-                            throw CompilationException("Property ${property.name} was declared as optional/transient but has no default value", null, null)
+                            throw CompilationException(
-                    }
+                                "Property ${property.name} was declared as optional/transient but has no default value",
-                    else {
+                                null,
-                        genValidateProperty(i, ::bitMaskOff)
+                                null
+                            )
+                    } else {
+                        genValidateProperty(i, bitMaskOff)
                         // todo: print name of each variable?
                         ificmpeq(throwLabel)
                     }
@@ -460,8 +468,9 @@ class SerializerCodegenImpl(
                 // result := ... <created object>
                 store(resultVar, serializableAsmType)
                 // set other properties
-                propVar = propsStartVar + properties.serializableConstructorProperties.map { codegen.typeMapper.mapType(it.type).size }.sum()
+                propVar = propsStartVar +
-                genSetSerializableStandaloneProperties(expressionCodegen, propVar, resultVar, ::bitMaskOff)
+                        properties.serializableConstructorProperties.map { codegen.typeMapper.mapType(it.type).size }.sum()
+                genSetSerializableStandaloneProperties(expressionCodegen, propVar, resultVar, bitMaskOff)
                 // load result
                 load(resultVar, serializableAsmType)
                 // will return result
@@ -491,8 +500,7 @@ class SerializerCodegenImpl(
         }
         if (!properties.primaryConstructorWithDefaults) {
             constructorDesc.append(")V")
-        }
+        } else {
-        else {
             val cnt = properties.serializableConstructorProperties.size.coerceAtMost(32) //only 32 default values are supported
             val mask = if (cnt == 32) -1 else ((1 shl cnt) - 1)
             load(bitMaskBase, OPT_MASK_TYPE)
@@ -505,7 +513,8 @@ class SerializerCodegenImpl(
     }
 
     private fun InstructionAdapter.genSetSerializableStandaloneProperties(
-            expressionCodegen: ExpressionCodegen, propVarStart: Int, resultVar: Int, bitMaskPos: (Int) -> Int) {
+        expressionCodegen: ExpressionCodegen, propVarStart: Int, resultVar: Int, bitMaskPos: (Int) -> Int
+    ) {
         var propVar = propVarStart
         val offset = properties.serializableConstructorProperties.size
         for ((index, property) in properties.serializableStandaloneProperties.withIndex()) {
@@ -518,8 +527,7 @@ class SerializerCodegenImpl(
                 // if (seen)
                 //    set
                 ificmpeq(nextLabel)
-            }
+            } else {
-            else {
                 // if (!seen)
                 //    throw
                 // set
@@ -530,9 +538,10 @@ class SerializerCodegenImpl(
 
             // generate setter call
             val propertyType = codegen.typeMapper.mapType(property.type)
-            expressionCodegen.intermediateValueForProperty(property.descriptor, false, null,
+            expressionCodegen.intermediateValueForProperty(
-                                                           StackValue.local(resultVar, serializableAsmType)).
+                property.descriptor, false, null,
-                    store(StackValue.local(propVar, propertyType), this)
+                StackValue.local(resultVar, serializableAsmType)
+            ).store(StackValue.local(propVar, propertyType), this)
             propVar += propertyType.size
             if (property.optional)
                 visitLabel(nextLabel)

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/resolve/KSerializerDescriptorResolver.kt

@@ -280,15 +280,19 @@ object KSerializerDescriptorResolver {
         val markerDesc = classDescriptor.getKSerializerConstructorMarker()
         val markerType = markerDesc.toSimpleType()
 
-        val parameterDescsAsProps = SerializableProperties(classDescriptor, bindingContext).serializableProperties.map { it.descriptor }
+        val serializableProperties = SerializableProperties(classDescriptor, bindingContext).serializableProperties
+        val parameterDescsAsProps = serializableProperties.map { it.descriptor }
+        val bitMaskSlotsCount = serializableProperties.bitMaskSlotCount()
         var i = 0
         val consParams = mutableListOf<ValueParameterDescriptor>()
+        repeat(bitMaskSlotsCount) {
             consParams.add(
                 ValueParameterDescriptorImpl(
-                functionDescriptor, null, i++, Annotations.EMPTY, Name.identifier("seen"), functionDescriptor.builtIns.intType, false,
+                    functionDescriptor, null, i++, Annotations.EMPTY, Name.identifier("seen$i"), functionDescriptor.builtIns.intType, false,
                     false, false, null, functionDescriptor.source
                 )
             )
+        }
         for (prop in parameterDescsAsProps) {
             consParams.add(
                 ValueParameterDescriptorImpl(

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/resolve/SerializableProperties.kt

@@ -74,3 +74,6 @@ class SerializableProperties(private val serializableClass: ClassDescriptor, val
     val primaryConstructorWithDefaults = serializableClass.unsubstitutedPrimaryConstructor
         ?.original?.valueParameters?.any { it.declaresDefaultValue() } ?: false
 }
+
+internal fun List<SerializableProperty>.bitMaskSlotCount() = size / 32 + 1
+internal fun bitMaskSlotAt(propertyIndex: Int) = propertyIndex / 32