Add SerializerFactory supertype for Native & JS in FIR serialization plugin.

This supertype is intended to be used with @AssociatedObject on platforms
where reflection possibilities are limited.

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

@@ -7,6 +7,8 @@ package org.jetbrains.kotlinx.serialization.compiler.backend.ir
 
 import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.ir.builders.IrBuilderWithScope
+import org.jetbrains.kotlin.ir.builders.declarations.addFunction
+import org.jetbrains.kotlin.ir.builders.declarations.addValueParameter
 import org.jetbrains.kotlin.ir.builders.irGet
 import org.jetbrains.kotlin.ir.builders.irInt
 import org.jetbrains.kotlin.ir.builders.irReturn
@@ -16,14 +18,14 @@ import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.expressions.impl.IrConstructorCallImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrGetValueImpl
 import org.jetbrains.kotlin.ir.types.defaultType
+import org.jetbrains.kotlin.ir.types.starProjectedType
+import org.jetbrains.kotlin.ir.types.typeWith
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.Name
-import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
 import org.jetbrains.kotlinx.serialization.compiler.extensions.SerializationPluginContext
 import org.jetbrains.kotlinx.serialization.compiler.resolve.SerialEntityNames
 import org.jetbrains.kotlinx.serialization.compiler.resolve.SerializationPackages
-import org.jetbrains.kotlinx.serialization.compiler.resolve.needSerializerFactory
 
 class SerializableCompanionIrGenerator(
     val irClass: IrClass,
@@ -149,14 +151,31 @@ class SerializableCompanionIrGenerator(
         generateSerializerFactoryIfNeeded(methodDescriptor)
     }
 
-    private fun generateSerializerFactoryIfNeeded(getterDescriptor: IrSimpleFunction) {
+    private fun getOrCreateSerializerVarargFactory(): IrSimpleFunction {
-        if (!irClass.needSerializerFactory(compilerContext)) return
+        irClass.findDeclaration<IrSimpleFunction> {
-        val serialFactoryDescriptor = irClass.findDeclaration<IrSimpleFunction> {
             it.valueParameters.size == 1
                     && it.valueParameters.first().isVararg
                     && it.returnType.isKSerializer()
                     && it.isFromPlugin()
-        } ?: return
+        }?.let { return it }
+        val kSerializerStarType = compilerContext.getClassFromRuntime(SerialEntityNames.KSERIALIZER_CLASS).starProjectedType
+        val f = irClass.addFunction(
+            SerialEntityNames.SERIALIZER_PROVIDER_NAME.asString(),
+            kSerializerStarType,
+            origin = SERIALIZATION_PLUGIN_ORIGIN
+        )
+        f.addValueParameter {
+            name = Name.identifier("typeParamsSerializers")
+            varargElementType = kSerializerStarType
+            type = compilerContext.irBuiltIns.arrayClass.typeWith(kSerializerStarType)
+            origin = SERIALIZATION_PLUGIN_ORIGIN
+        }
+        return f
+    }
+
+    private fun generateSerializerFactoryIfNeeded(getterDescriptor: IrSimpleFunction) {
+        if (!irClass.needSerializerFactory(compilerContext)) return
+        val serialFactoryDescriptor = getOrCreateSerializerVarargFactory()
         addFunctionBody(serialFactoryDescriptor) { factory ->
             val kSerializerStarType = factory.returnType
             val array = factory.valueParameters.first()

plugins/kotlinx-serialization/kotlinx-serialization.common/src/org/jetbrains/kotlinx/serialization/compiler/resolve/NamingConventions.kt

@@ -83,6 +83,8 @@ object SerialEntityNames {
     val GENERATED_SERIALIZER_CLASS = Name.identifier("GeneratedSerializer")
     val GENERATED_SERIALIZER_FQ = SerializationPackages.internalPackageFqName.child(GENERATED_SERIALIZER_CLASS)
 
+    val SERIALIZER_FACTORY_INTERFACE_NAME = Name.identifier("SerializerFactory")
+
     const val ENCODER_CLASS = "Encoder"
     const val STRUCTURE_ENCODER_CLASS = "CompositeEncoder"
     const val DECODER_CLASS = "Decoder"

plugins/kotlinx-serialization/kotlinx-serialization.k2/build.gradle.kts

@@ -10,6 +10,8 @@ dependencies {
     compileOnly(project(":compiler:fir:tree"))
     compileOnly(project(":compiler:fir:resolve"))
     compileOnly(project(":compiler:fir:entrypoint"))
+    compileOnly(project(":js:js.config"))
+    compileOnly(project(":compiler:cli-common"))
 
     implementation(project(":kotlinx-serialization-compiler-plugin.common"))
 

plugins/kotlinx-serialization/kotlinx-serialization.k2/src/org/jetbrains/kotlinx/serialization/compiler/fir/SerializationFirResolveExtension.kt

@@ -32,7 +32,10 @@ import org.jetbrains.kotlin.name.CallableId
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.name.SpecialNames
+import org.jetbrains.kotlin.platform.js.isJs
+import org.jetbrains.kotlin.platform.konan.isNative
 import org.jetbrains.kotlinx.serialization.compiler.resolve.SerialEntityNames
+import org.jetbrains.kotlinx.serialization.compiler.resolve.SerialEntityNames.SERIALIZER_FACTORY_INTERFACE_NAME
 import org.jetbrains.kotlinx.serialization.compiler.resolve.SerializationPackages
 
 val generatedSerializerClassId = ClassId(SerializationPackages.internalPackageFqName, SerialEntityNames.GENERATED_SERIALIZER_CLASS)
@@ -321,6 +324,10 @@ class SerializationFirResolveExtension(session: FirSession) : FirDeclarationGene
             name = SpecialNames.DEFAULT_NAME_FOR_COMPANION_OBJECT
             symbol = FirRegularClassSymbol(classId)
             superTypeRefs += session.builtinTypes.anyType
+            if (owner.companionNeedsSerializerFactory()) {
+                val serializerFactoryClassId = ClassId(SerializationPackages.internalPackageFqName, SERIALIZER_FACTORY_INTERFACE_NAME)
+                superTypeRefs += serializerFactoryClassId.constructClassLikeType(emptyArray(), false).toFirResolvedTypeRef()
+            }
         }
         return regularClass.symbol
     }
@@ -328,4 +335,14 @@ class SerializationFirResolveExtension(session: FirSession) : FirDeclarationGene
     override fun FirDeclarationPredicateRegistrar.registerPredicates() {
         register(FirSerializationPredicates.annotatedWithSerializable)
     }
+
+    private fun FirClassSymbol<*>.companionNeedsSerializerFactory(): Boolean {
+        if (!(moduleData.platform.isNative() || moduleData.platform.isJs())) return false
+        if (isSerializableObject) return true
+        if (isSerializableEnum) return true
+        if (isAbstractOrSealedSerializableClass) return true
+        if (isSealedSerializableInterface) return true
+        if (typeParameterSymbols.isEmpty()) return false
+        return true
+    }
 }

plugins/kotlinx-serialization/kotlinx-serialization.k2/src/org/jetbrains/kotlinx/serialization/compiler/fir/SerializationFirUtils.kt

@@ -157,6 +157,9 @@ internal val FirClassSymbol<*>.isInternalSerializable: Boolean
         return hasSerializableAnnotationWithoutArgs
     }
 
+internal val FirClassSymbol<*>.isAbstractOrSealedSerializableClass: Boolean
+    get() = isInternalSerializable && (rawStatus.modality == Modality.ABSTRACT || rawStatus.modality == Modality.SEALED)
+
 internal val FirClassSymbol<*>.isInternallySerializableEnum: Boolean
     get() = classKind.isEnumClass && hasSerializableAnnotationWithoutArgs