KT-4107 Data objects

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/MethodsFromAnyGeneratorForLowerings.kt

@@ -14,17 +14,13 @@ import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.builders.declarations.addFunction
 import org.jetbrains.kotlin.ir.builders.declarations.addValueParameter
 import org.jetbrains.kotlin.ir.declarations.*
-import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.expressions.IrMemberAccessExpression
 import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.types.classOrNull
 import org.jetbrains.kotlin.ir.types.getClass
 import org.jetbrains.kotlin.ir.types.isArray
-import org.jetbrains.kotlin.ir.util.DataClassMembersGenerator
-import org.jetbrains.kotlin.ir.util.SYNTHETIC_OFFSET
-import org.jetbrains.kotlin.ir.util.functions
-import org.jetbrains.kotlin.ir.util.isPrimitiveArray
+import org.jetbrains.kotlin.ir.util.*
 
 class MethodsFromAnyGeneratorForLowerings(val context: BackendContext, val irClass: IrClass, val origin: IrDeclarationOrigin) {
     private fun IrClass.addSyntheticFunction(name: String, returnType: IrType) =
@@ -74,6 +70,7 @@ open class LoweringDataClassMemberGenerator(
         IrGeneratorContextBase(backendContext.irBuiltIns),
         backendContext.ir.symbols.externalSymbolTable,
         irClass,
+        irClass.kotlinFqName,
         origin,
         forbidDirectFieldAccess
     ) {

compiler/ir/backend.jvm/lower/src/org/jetbrains/kotlin/backend/jvm/JvmLower.kt

@@ -353,6 +353,7 @@ private val jvmFilePhases = listOf(
 
     enumClassPhase,
     objectClassPhase,
+    readResolveForDataObjectsPhase,
     staticInitializersPhase,
     initializersPhase,
     initializersCleanupPhase,

compiler/ir/backend.jvm/lower/src/org/jetbrains/kotlin/backend/jvm/lower/ReadResolveForDataObjectsLowering.kt

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2010-2022 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.backend.jvm.lower
+
+import org.jetbrains.kotlin.backend.common.ClassLoweringPass
+import org.jetbrains.kotlin.backend.common.ir.addDispatchReceiver
+import org.jetbrains.kotlin.backend.common.phaser.makeIrFilePhase
+import org.jetbrains.kotlin.backend.jvm.JvmBackendContext
+import org.jetbrains.kotlin.backend.jvm.ir.createJvmIrBuilder
+import org.jetbrains.kotlin.config.LanguageFeature
+import org.jetbrains.kotlin.descriptors.ClassKind
+import org.jetbrains.kotlin.descriptors.DescriptorVisibilities
+import org.jetbrains.kotlin.descriptors.Modality
+import org.jetbrains.kotlin.ir.builders.declarations.buildFun
+import org.jetbrains.kotlin.ir.builders.irExprBody
+import org.jetbrains.kotlin.ir.builders.irGetField
+import org.jetbrains.kotlin.ir.declarations.IrClass
+import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
+import org.jetbrains.kotlin.ir.util.defaultType
+import org.jetbrains.kotlin.ir.util.fields
+import org.jetbrains.kotlin.ir.util.getAllSuperclasses
+import org.jetbrains.kotlin.ir.util.hasEqualFqName
+import org.jetbrains.kotlin.load.java.JvmAbi
+import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.name.Name
+
+internal val readResolveForDataObjectsPhase = makeIrFilePhase(
+    ::ReadResolveForDataObjectsLowering,
+    name = "ReadResolveForDataObjectsLowering",
+    description = "Generate readResolve for serializable data objects"
+)
+
+private class ReadResolveForDataObjectsLowering(val context: JvmBackendContext) : ClassLoweringPass {
+    override fun lower(irClass: IrClass) {
+        if (!context.state.languageVersionSettings.supportsFeature(LanguageFeature.DataObjects)) return
+
+        if (!irClass.isData || irClass.kind != ClassKind.OBJECT || !irClass.isSerializable()) return
+
+        context.irFactory.buildFun {
+            name = Name.identifier("readResolve")
+            modality = Modality.FINAL
+            origin = IrDeclarationOrigin.GENERATED_DATA_CLASS_MEMBER
+            returnType = context.irBuiltIns.anyType
+            visibility = DescriptorVisibilities.PRIVATE
+        }.apply {
+            addDispatchReceiver { type = irClass.defaultType }
+            parent = irClass
+            body = context.createJvmIrBuilder(symbol).run {
+                val instanceField = irClass.fields.single { it.name.asString() == JvmAbi.INSTANCE_FIELD }
+                irExprBody(irGetField(null, instanceField))
+            }
+            irClass.declarations.add(this)
+        }
+    }
+}
+
+private val SERIALIZABLE_FQ_NAME = FqName("java.io.Serializable")
+
+private fun IrClass.isSerializable(): Boolean =
+    getAllSuperclasses().any { it.hasEqualFqName(SERIALIZABLE_FQ_NAME) }

compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/DataClassMembersGenerator.kt

@@ -74,8 +74,9 @@ class DataClassMembersGenerator(
         val origin: IrDeclarationOrigin
     ) : DataClassMethodGenerator(ktClassOrObject, declarationGenerator.context.bindingContext) {
 
-        private val irDataClassMembersGenerator =
-            object : DataClassMembersGenerator(context, context.symbolTable, irClass, origin, generateBodies = generateBodies) {
+        private val irDataClassMembersGenerator = object : DataClassMembersGenerator(
+            context, context.symbolTable, irClass, ktClassOrObject.fqName, origin, generateBodies = generateBodies
+        ) {
             override fun declareSimpleFunction(startOffset: Int, endOffset: Int, functionDescriptor: FunctionDescriptor): IrFunction =
                 declareSimpleFunction(startOffset, endOffset, origin, functionDescriptor)
 

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/DataClassMembersGenerator.kt

@@ -19,6 +19,7 @@ import org.jetbrains.kotlin.ir.symbols.impl.IrVariableSymbolImpl
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.types.classifierOrNull
 import org.jetbrains.kotlin.ir.types.isNullable
+import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 
 /**
@@ -32,6 +33,7 @@ abstract class DataClassMembersGenerator(
     val context: IrGeneratorContext,
     val symbolTable: ReferenceSymbolTable,
     val irClass: IrClass,
+    val fqName: FqName?,
     val origin: IrDeclarationOrigin,
     val forbidDirectFieldAccess: Boolean = false,
     val generateBodies: Boolean = false
@@ -139,9 +141,9 @@ abstract class DataClassMembersGenerator(
             +irReturnTrue()
         }
 
-        fun generateHashCodeMethodBody(properties: List<IrProperty>) {
+        fun generateHashCodeMethodBody(properties: List<IrProperty>, constHashCode: Int) {
             if (properties.isEmpty()) {
-                +irReturn(irInt(0))
+                +irReturn(irInt(constHashCode))
                 return
             } else if (properties.size == 1) {
                 +irReturn(getHashCodeOfProperty(properties[0]))
@@ -186,6 +188,10 @@ abstract class DataClassMembersGenerator(
         }
 
         fun generateToStringMethodBody(properties: List<IrProperty>) {
+            if (properties.isEmpty() && irClass.kind == ClassKind.OBJECT) {
+                +irReturn(irString(irClass.name.asString()))
+                return
+            }
             val irConcat = irConcat()
             irConcat.addArgument(irString(irClass.classNameForToString() + "("))
             var first = true
@@ -259,6 +265,7 @@ abstract class DataClassMembersGenerator(
     ) {
         MemberFunctionBuilder(startOffset, endOffset, declareSimpleFunction(startOffset, endOffset, function)).addToClass { irFunction ->
             irFunction.buildWithScope {
+                irFunction.parent = irClass
                 generateSyntheticFunctionParameterDeclarations(irFunction)
                 body(irFunction)
             }
@@ -344,14 +351,20 @@ abstract class DataClassMembersGenerator(
     // Entry for psi2ir
     fun generateHashCodeMethod(function: FunctionDescriptor, properties: List<PropertyDescriptor>) {
         buildMember(function) {
-            generateHashCodeMethodBody(properties.map { getIrProperty(it) })
+            generateHashCodeMethodBody(
+                properties.map { getIrProperty(it) },
+                if (irClass.kind == ClassKind.OBJECT && irClass.isData) fqName.hashCode() else 0
+            )
         }
     }
 
     // Entry for fir2ir
     fun generateHashCodeMethod(irFunction: IrFunction, properties: List<IrProperty>) {
         buildMember(irFunction) {
-            generateHashCodeMethodBody(properties)
+            generateHashCodeMethodBody(
+                properties,
+                if (irClass.kind == ClassKind.OBJECT && irClass.isData) fqName.hashCode() else 0
+            )
         }
     }