[FIR/IR generator] Introduce the common entry point for tree generators

This reduces code duplication.

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/Main.kt

@@ -6,31 +6,36 @@
 package org.jetbrains.kotlin.fir.tree.generator
 
 import org.jetbrains.kotlin.fir.tree.generator.context.AbstractFirTreeBuilder
-import org.jetbrains.kotlin.fir.tree.generator.printer.generateElements
-import org.jetbrains.kotlin.generators.tree.InterfaceAndAbstractClassConfigurator
+import org.jetbrains.kotlin.fir.tree.generator.printer.*
 import org.jetbrains.kotlin.generators.tree.Model
-import org.jetbrains.kotlin.generators.tree.addPureAbstractElement
-import org.jetbrains.kotlin.generators.tree.detectBaseTransformerTypes
-import org.jetbrains.kotlin.generators.util.GeneratorsFileUtil
-import org.jetbrains.kotlin.generators.util.GeneratorsFileUtil.collectPreviouslyGeneratedFiles
-import org.jetbrains.kotlin.generators.util.GeneratorsFileUtil.removeExtraFilesFromPreviousGeneration
+import org.jetbrains.kotlin.generators.tree.bind
+import org.jetbrains.kotlin.generators.tree.printer.generateTree
 import java.io.File
 
+internal const val BASE_PACKAGE = "org.jetbrains.kotlin.fir"
+internal const val VISITOR_PACKAGE = "$BASE_PACKAGE.visitors"
 
 fun main(args: Array<String>) {
     val generationPath = args.firstOrNull()?.let { File(it) }
         ?: File("../../tree/gen").canonicalFile
-
     NodeConfigurator.configureFields()
     val model = Model(FirTreeBuilder.elements, AbstractFirTreeBuilder.baseFirElement)
-    detectBaseTransformerTypes(model)
-    ImplementationConfigurator.configureImplementations(model)
-    InterfaceAndAbstractClassConfigurator((model.elements + model.elements.flatMap { it.allImplementations }))
-        .configureInterfacesAndAbstractClasses()
-    addPureAbstractElement(FirTreeBuilder.elements, pureAbstractElementType)
-    BuilderConfigurator.configureBuilders()
-    val previouslyGeneratedFiles = collectPreviouslyGeneratedFiles(generationPath)
-    val generatedFiles = generateElements(FirTreeBuilder, BuilderConfigurator, generationPath)
-    generatedFiles.forEach { GeneratorsFileUtil.writeFileIfContentChanged(it.file, it.newText, logNotChanged = false) }
-    removeExtraFilesFromPreviousGeneration(previouslyGeneratedFiles, generatedFiles.map { it.file })
+    generateTree(
+        generationPath,
+        "compiler/fir/tree/tree-generator/Readme.md",
+        model,
+        pureAbstractElementType,
+        ::ElementPrinter,
+        listOf(
+            firVisitorType to ::VisitorPrinter.bind(false),
+            firDefaultVisitorType to ::VisitorPrinter.bind(true),
+            firVisitorVoidType to ::VisitorVoidPrinter,
+            firDefaultVisitorVoidType to ::DefaultVisitorVoidPrinter,
+            firTransformerType to ::TransformerPrinter,
+        ),
+        ImplementationConfigurator,
+        BuilderConfigurator,
+        ::ImplementationPrinter,
+        ::BuilderPrinter,
+    )
 }

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/Types.kt

@@ -15,7 +15,6 @@ import org.jetbrains.kotlin.descriptors.Visibility
 import org.jetbrains.kotlin.descriptors.annotations.AnnotationUseSiteTarget
 import org.jetbrains.kotlin.fir.tree.generator.context.generatedType
 import org.jetbrains.kotlin.fir.tree.generator.context.type
-import org.jetbrains.kotlin.fir.tree.generator.printer.VISITOR_PACKAGE
 import org.jetbrains.kotlin.fir.types.ConeClassLikeType
 import org.jetbrains.kotlin.fir.types.ConeErrorType
 import org.jetbrains.kotlin.fir.types.ConeKotlinType

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/context/AbstractFirTreeBuilder.kt

@@ -5,9 +5,9 @@
 
 package org.jetbrains.kotlin.fir.tree.generator.context
 
+import org.jetbrains.kotlin.fir.tree.generator.BASE_PACKAGE
 import org.jetbrains.kotlin.fir.tree.generator.model.Element
 import org.jetbrains.kotlin.fir.tree.generator.model.ElementRef
-import org.jetbrains.kotlin.fir.tree.generator.printer.BASE_PACKAGE
 import org.jetbrains.kotlin.generators.tree.ClassRef
 import org.jetbrains.kotlin.generators.tree.PositionTypeParameterRef
 import org.jetbrains.kotlin.generators.tree.TypeKind

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/importables.kt

@@ -5,7 +5,6 @@
 
 package org.jetbrains.kotlin.fir.tree.generator
 
-import org.jetbrains.kotlin.fir.tree.generator.printer.VISITOR_PACKAGE
 import org.jetbrains.kotlin.generators.tree.ArbitraryImportable
 
 val phaseAsResolveStateExtentionImport = ArbitraryImportable("org.jetbrains.kotlin.fir.declarations", "asResolveState")

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/model/Element.kt

@@ -5,7 +5,7 @@
 
 package org.jetbrains.kotlin.fir.tree.generator.model
 
-import org.jetbrains.kotlin.fir.tree.generator.printer.BASE_PACKAGE
+import org.jetbrains.kotlin.fir.tree.generator.BASE_PACKAGE
 import org.jetbrains.kotlin.fir.tree.generator.printer.safeDecapitalizedName
 import org.jetbrains.kotlin.generators.tree.*
 import org.jetbrains.kotlin.generators.tree.ElementOrRef as GenericElementOrRef

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/printer/BuilderPrinter.kt

@@ -8,28 +8,17 @@ package org.jetbrains.kotlin.fir.tree.generator.printer
 import org.jetbrains.kotlin.fir.tree.generator.declarationAttributesType
 import org.jetbrains.kotlin.fir.tree.generator.firBuilderDslAnnotation
 import org.jetbrains.kotlin.fir.tree.generator.firImplementationDetailType
-import org.jetbrains.kotlin.fir.tree.generator.model.*
+import org.jetbrains.kotlin.fir.tree.generator.model.Element
+import org.jetbrains.kotlin.fir.tree.generator.model.Field
+import org.jetbrains.kotlin.fir.tree.generator.model.FieldWithDefault
+import org.jetbrains.kotlin.fir.tree.generator.model.Implementation
 import org.jetbrains.kotlin.fir.tree.generator.toMutableOrEmptyImport
 import org.jetbrains.kotlin.generators.tree.AbstractBuilderPrinter
 import org.jetbrains.kotlin.generators.tree.ClassRef
 import org.jetbrains.kotlin.generators.tree.ImportCollector
-import org.jetbrains.kotlin.generators.tree.printer.GeneratedFile
-import org.jetbrains.kotlin.generators.tree.printer.printGeneratedType
 import org.jetbrains.kotlin.utils.SmartPrinter
-import java.io.File
 
-fun Builder.generateCode(generationPath: File): GeneratedFile =
-    printGeneratedType(
-        generationPath,
-        TREE_GENERATOR_README,
-        packageName,
-        typeName,
-        fileSuppressions = listOf("DuplicatedCode", "unused"),
-    ) {
-        BuilderPrinter(this).printBuilder(this@generateCode)
-    }
-
-class BuilderPrinter(printer: SmartPrinter) : AbstractBuilderPrinter<Element, Implementation, FieldWithDefault, Field>(printer) {
+internal class BuilderPrinter(printer: SmartPrinter) : AbstractBuilderPrinter<Element, Implementation, FieldWithDefault, Field>(printer) {
 
     override val implementationDetailAnnotation: ClassRef<*>
         get() = firImplementationDetailType

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/printer/DefaultVisitorVoidPrinter.kt

@@ -5,15 +5,13 @@
 
 package org.jetbrains.kotlin.fir.tree.generator.printer
 
-import org.jetbrains.kotlin.fir.tree.generator.firDefaultVisitorVoidType
 import org.jetbrains.kotlin.fir.tree.generator.firVisitorVoidType
 import org.jetbrains.kotlin.fir.tree.generator.model.Element
 import org.jetbrains.kotlin.fir.tree.generator.model.Field
 import org.jetbrains.kotlin.generators.tree.*
 import org.jetbrains.kotlin.utils.SmartPrinter
-import java.io.File
 
-private class DefaultVisitorVoidPrinter(
+internal class DefaultVisitorVoidPrinter(
     printer: SmartPrinter,
     override val visitorType: ClassRef<*>,
 ) : AbstractVisitorPrinter<Element, Field>(printer) {
@@ -46,6 +44,3 @@ private class DefaultVisitorVoidPrinter(
         }
     }
 }
-
-fun printDefaultVisitorVoid(elements: List<Element>, generationPath: File) =
-    printVisitorCommon(elements, generationPath, firDefaultVisitorVoidType, ::DefaultVisitorVoidPrinter)

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/printer/ElementPrinter.kt

@@ -9,13 +9,14 @@ import org.jetbrains.kotlin.fir.tree.generator.*
 import org.jetbrains.kotlin.fir.tree.generator.context.AbstractFirTreeBuilder
 import org.jetbrains.kotlin.fir.tree.generator.model.Element
 import org.jetbrains.kotlin.fir.tree.generator.model.Field
-import org.jetbrains.kotlin.generators.tree.get
 import org.jetbrains.kotlin.generators.tree.*
-import org.jetbrains.kotlin.generators.tree.printer.*
+import org.jetbrains.kotlin.generators.tree.printer.printAcceptChildrenMethod
+import org.jetbrains.kotlin.generators.tree.printer.printAcceptMethod
+import org.jetbrains.kotlin.generators.tree.printer.printTransformChildrenMethod
+import org.jetbrains.kotlin.generators.tree.printer.printTransformMethod
 import org.jetbrains.kotlin.utils.SmartPrinter
-import java.io.File
 
-private class ElementPrinter(printer: SmartPrinter) : AbstractElementPrinter<Element, Field>(printer) {
+internal class ElementPrinter(printer: SmartPrinter) : AbstractElementPrinter<Element, Field>(printer) {
 
     override fun makeFieldPrinter(printer: SmartPrinter) = object : AbstractFieldPrinter<Field>(printer) {}
 
@@ -89,8 +90,3 @@ private class ElementPrinter(printer: SmartPrinter) : AbstractElementPrinter<Ele
         }
     }
 }
-
-fun Element.generateCode(generationPath: File): GeneratedFile =
-    printGeneratedType(generationPath, TREE_GENERATOR_README, packageName, typeName) {
-        ElementPrinter(this).printElement(element)
-    }

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/printer/ImplementationPrinter.kt

@@ -9,21 +9,12 @@ import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.fir.tree.generator.*
 import org.jetbrains.kotlin.fir.tree.generator.model.*
 import org.jetbrains.kotlin.generators.tree.*
-import org.jetbrains.kotlin.generators.tree.printer.*
+import org.jetbrains.kotlin.generators.tree.printer.call
+import org.jetbrains.kotlin.generators.tree.printer.printAcceptChildrenMethod
+import org.jetbrains.kotlin.generators.tree.printer.printBlock
+import org.jetbrains.kotlin.generators.tree.printer.printTransformChildrenMethod
 import org.jetbrains.kotlin.utils.SmartPrinter
 import org.jetbrains.kotlin.utils.withIndent
-import java.io.File
-
-fun Implementation.generateCode(generationPath: File): GeneratedFile =
-    printGeneratedType(
-        generationPath,
-        TREE_GENERATOR_README,
-        packageName,
-        this.typeName,
-        fileSuppressions = listOf("DuplicatedCode", "unused"),
-    ) {
-        ImplementationPrinter(this).printImplementation(this@generateCode)
-    }
 
 private class ImplementationFieldPrinter(printer: SmartPrinter) : AbstractFieldPrinter<FieldWithDefault>(printer) {
 
@@ -38,7 +29,7 @@ private class ImplementationFieldPrinter(printer: SmartPrinter) : AbstractFieldP
     override fun actualTypeOfField(field: FieldWithDefault) = field.getMutableType()
 }
 
-private class ImplementationPrinter(
+internal class ImplementationPrinter(
     printer: SmartPrinter
 ) : AbstractImplementationPrinter<Implementation, Element, FieldWithDefault>(printer) {
 
@@ -49,7 +40,7 @@ private class ImplementationPrinter(
     override val pureAbstractElementType: ClassRef<*>
         get() = org.jetbrains.kotlin.fir.tree.generator.pureAbstractElementType
 
-    override fun makeFieldPrinter(printer: SmartPrinter) = ImplementationFieldPrinter(printer)
+    override fun makeFieldPrinter(printer: SmartPrinter): AbstractFieldPrinter<FieldWithDefault> = ImplementationFieldPrinter(printer)
 
     context(ImportCollector)
     override fun SmartPrinter.printAdditionalMethods(implementation: Implementation) {

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/printer/TransformerPrinter.kt

@@ -7,22 +7,21 @@ package org.jetbrains.kotlin.fir.tree.generator.printer
 
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.fir.tree.generator.context.AbstractFirTreeBuilder
-import org.jetbrains.kotlin.fir.tree.generator.firTransformerType
 import org.jetbrains.kotlin.fir.tree.generator.firVisitorType
 import org.jetbrains.kotlin.fir.tree.generator.model.Element
 import org.jetbrains.kotlin.fir.tree.generator.model.Field
 import org.jetbrains.kotlin.generators.tree.*
-import org.jetbrains.kotlin.generators.tree.printer.*
+import org.jetbrains.kotlin.generators.tree.printer.FunctionParameter
+import org.jetbrains.kotlin.generators.tree.printer.printBlock
+import org.jetbrains.kotlin.generators.tree.printer.printFunctionDeclaration
+import org.jetbrains.kotlin.generators.tree.printer.printFunctionWithBlockBody
 import org.jetbrains.kotlin.utils.SmartPrinter
-import java.io.File
 
-private class TransformerPrinter(
+internal class TransformerPrinter(
     printer: SmartPrinter,
+    override val visitorType: ClassRef<*>,
 ) : AbstractVisitorPrinter<Element, Field>(printer) {
 
-    override val visitorType: ClassRef<*>
-        get() = firTransformerType
-
     override val visitorSuperType: ClassRef<PositionTypeParameterRef>
         get() = firVisitorType.withArgs(AbstractFirTreeBuilder.baseFirElement, visitorDataType)
 
@@ -88,13 +87,3 @@ private class TransformerPrinter(
         }
     }
 }
-
-fun printTransformer(elements: List<Element>, generationPath: File): GeneratedFile =
-    printGeneratedType(
-        generationPath,
-        TREE_GENERATOR_README,
-        firTransformerType.packageName,
-        firTransformerType.simpleName,
-    ) {
-        TransformerPrinter(this).printVisitor(elements)
-    }

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/printer/VisitorPrinter.kt

@@ -6,15 +6,13 @@
 package org.jetbrains.kotlin.fir.tree.generator.printer
 
 import org.jetbrains.kotlin.fir.tree.generator.context.AbstractFirTreeBuilder
-import org.jetbrains.kotlin.fir.tree.generator.firDefaultVisitorType
 import org.jetbrains.kotlin.fir.tree.generator.firVisitorType
 import org.jetbrains.kotlin.fir.tree.generator.model.Element
 import org.jetbrains.kotlin.fir.tree.generator.model.Field
 import org.jetbrains.kotlin.generators.tree.*
 import org.jetbrains.kotlin.utils.SmartPrinter
-import java.io.File
 
-private class VisitorPrinter(
+internal class VisitorPrinter(
     printer: SmartPrinter,
     override val visitorType: ClassRef<*>,
     private val visitSuperTypeByDefault: Boolean,
@@ -42,13 +40,3 @@ private class VisitorPrinter(
         else -> AbstractFirTreeBuilder.baseFirElement
     }
 }
-
-fun printVisitor(elements: List<Element>, generationPath: File, visitSuperTypeByDefault: Boolean) =
-    printVisitorCommon(
-        elements,
-        generationPath,
-        if (visitSuperTypeByDefault) firDefaultVisitorType else firVisitorType,
-    ) { printer, visitorType ->
-        VisitorPrinter(printer, visitorType, visitSuperTypeByDefault)
-    }
-

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/printer/VisitorVoidPrinter.kt

@@ -7,16 +7,14 @@ package org.jetbrains.kotlin.fir.tree.generator.printer
 
 import org.jetbrains.kotlin.fir.tree.generator.context.AbstractFirTreeBuilder
 import org.jetbrains.kotlin.fir.tree.generator.firVisitorType
-import org.jetbrains.kotlin.fir.tree.generator.firVisitorVoidType
 import org.jetbrains.kotlin.fir.tree.generator.model.Element
 import org.jetbrains.kotlin.fir.tree.generator.model.Field
 import org.jetbrains.kotlin.generators.tree.AbstractVisitorVoidPrinter
 import org.jetbrains.kotlin.generators.tree.ClassRef
 import org.jetbrains.kotlin.generators.tree.PositionTypeParameterRef
 import org.jetbrains.kotlin.utils.SmartPrinter
-import java.io.File
 
-private class VisitorVoidPrinter(
+internal class VisitorVoidPrinter(
     printer: SmartPrinter,
     override val visitorType: ClassRef<*>,
 ) : AbstractVisitorVoidPrinter<Element, Field>(printer) {
@@ -35,6 +33,3 @@ private class VisitorVoidPrinter(
 
     override fun parentInVisitor(element: Element): Element = AbstractFirTreeBuilder.baseFirElement
 }
-
-fun printVisitorVoid(elements: List<Element>, generationPath: File) =
-    printVisitorCommon(elements, generationPath, firVisitorVoidType, ::VisitorVoidPrinter)

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/printer/main.kt

@@ -1,37 +0,0 @@
-/*
- * Copyright 2010-2020 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.fir.tree.generator.printer
-
-import org.jetbrains.kotlin.fir.tree.generator.context.AbstractFirBuilderConfigurator
-import org.jetbrains.kotlin.fir.tree.generator.context.AbstractFirTreeBuilder
-import org.jetbrains.kotlin.generators.tree.printer.GeneratedFile
-import org.jetbrains.kotlin.generators.util.GeneratorsFileUtil.GENERATED_MESSAGE
-import org.jetbrains.kotlin.utils.SmartPrinter
-import java.io.File
-
-const val VISITOR_PACKAGE = "org.jetbrains.kotlin.fir.visitors"
-const val BASE_PACKAGE = "org.jetbrains.kotlin.fir"
-
-internal const val TREE_GENERATOR_README = "compiler/fir/tree/tree-generator/Readme.md"
-
-fun generateElements(
-    builder: AbstractFirTreeBuilder,
-    builderConfigurator: AbstractFirBuilderConfigurator<*>,
-    generationPath: File,
-): List<GeneratedFile> {
-    val generatedFiles = mutableListOf<GeneratedFile>()
-    builder.elements.mapTo(generatedFiles) { it.generateCode(generationPath) }
-    builder.elements.flatMap { it.allImplementations }.mapTo(generatedFiles) { it.generateCode(generationPath) }
-    builder.elements.flatMap { it.allImplementations }.mapNotNull { it.builder }.mapTo(generatedFiles) { it.generateCode(generationPath) }
-    builderConfigurator.intermediateBuilders.mapTo(generatedFiles) { it.generateCode(generationPath) }
-
-    generatedFiles += printVisitor(builder.elements, generationPath, false)
-    generatedFiles += printVisitorVoid(builder.elements, generationPath)
-    generatedFiles += printVisitor(builder.elements, generationPath, true)
-    generatedFiles += printDefaultVisitorVoid(builder.elements, generationPath)
-    generatedFiles += printTransformer(builder.elements, generationPath)
-    return generatedFiles
-}

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/printer/utils.kt

@@ -6,15 +6,16 @@
 package org.jetbrains.kotlin.fir.tree.generator.printer
 
 import org.jetbrains.kotlin.descriptors.Modality
+import org.jetbrains.kotlin.fir.tree.generator.BASE_PACKAGE
 import org.jetbrains.kotlin.fir.tree.generator.firTransformerType
-import org.jetbrains.kotlin.fir.tree.generator.model.*
+import org.jetbrains.kotlin.fir.tree.generator.model.Element
+import org.jetbrains.kotlin.fir.tree.generator.model.Field
+import org.jetbrains.kotlin.fir.tree.generator.model.FieldList
+import org.jetbrains.kotlin.fir.tree.generator.model.FieldWithDefault
 import org.jetbrains.kotlin.generators.tree.*
 import org.jetbrains.kotlin.generators.tree.printer.FunctionParameter
-import org.jetbrains.kotlin.generators.tree.printer.GeneratedFile
 import org.jetbrains.kotlin.generators.tree.printer.printFunctionDeclaration
-import org.jetbrains.kotlin.generators.tree.printer.printGeneratedType
 import org.jetbrains.kotlin.utils.SmartPrinter
-import java.io.File
 
 context(ImportCollector)
 fun SmartPrinter.transformFunctionDeclaration(
@@ -92,13 +93,3 @@ fun Field.getMutableType(forBuilder: Boolean = false): TypeRefWithNullability =
 }
 
 val Element.safeDecapitalizedName: String get() = if (name == "Class") "klass" else name.replaceFirstChar(Char::lowercaseChar)
-
-internal fun printVisitorCommon(
-    elements: List<Element>,
-    generationPath: File,
-    visitorType: ClassRef<*>,
-    makePrinter: (SmartPrinter, ClassRef<*>) -> AbstractVisitorPrinter<Element, Field>,
-): GeneratedFile =
-    printGeneratedType(generationPath, TREE_GENERATOR_README, visitorType.packageName, visitorType.simpleName) {
-        makePrinter(this, visitorType).printVisitor(elements)
-    }

compiler/ir/ir.tree/tree-generator/build.gradle.kts

@@ -9,7 +9,6 @@ val compileOnly by configurations
 runtimeOnly.extendsFrom(compileOnly)
 
 dependencies {
-    implementation(project(":generators"))
     implementation(project(":generators:tree-generator-common"))
     implementation(project(":compiler:util"))
 

compiler/ir/ir.tree/tree-generator/src/org/jetbrains/kotlin/ir/generator/Main.kt

@@ -5,11 +5,8 @@
 
 package org.jetbrains.kotlin.ir.generator
 
-import org.jetbrains.kotlin.generators.tree.InterfaceAndAbstractClassConfigurator
-import org.jetbrains.kotlin.generators.tree.addPureAbstractElement
-import org.jetbrains.kotlin.generators.util.GeneratorsFileUtil
-import org.jetbrains.kotlin.generators.util.GeneratorsFileUtil.collectPreviouslyGeneratedFiles
-import org.jetbrains.kotlin.generators.util.GeneratorsFileUtil.removeExtraFilesFromPreviousGeneration
+import org.jetbrains.kotlin.generators.tree.bind
+import org.jetbrains.kotlin.generators.tree.printer.generateTree
 import org.jetbrains.kotlin.ir.generator.model.markLeaves
 import org.jetbrains.kotlin.ir.generator.print.*
 import java.io.File
@@ -21,25 +18,24 @@ internal const val TREE_GENERATOR_README = "compiler/ir/ir.tree/tree-generator/R
 fun main(args: Array<String>) {
     val generationPath = args.firstOrNull()?.let { File(it) }
         ?: File("compiler/ir/ir.tree/gen").canonicalFile
-
     val model = IrTree.build()
-
-    InterfaceAndAbstractClassConfigurator(model.elements).configureInterfacesAndAbstractClasses()
-    addPureAbstractElement(model.elements, elementBaseType)
-    markLeaves(model.elements)
-
-    val previouslyGeneratedFiles = collectPreviouslyGeneratedFiles(generationPath)
-    val generatedFiles = sequence {
-        yieldAll(printElements(generationPath, model))
-        yield(printVisitor(generationPath, model))
-        yield(printVisitorVoid(generationPath, model))
-        yield(printTransformer(generationPath, model))
-        yield(printTransformerVoid(generationPath, model))
-        yield(printTypeVisitor(generationPath, model))
-        yield(printFactory(generationPath, model))
-    }.map {
-        GeneratorsFileUtil.writeFileIfContentChanged(it.file, it.newText, logNotChanged = false)
-        it.file
-    }.toList()
-    removeExtraFilesFromPreviousGeneration(previouslyGeneratedFiles, generatedFiles)
+    generateTree(
+        generationPath,
+        TREE_GENERATOR_README,
+        model,
+        elementBaseType,
+        ::ElementPrinter,
+        listOf(
+            elementVisitorType to ::VisitorPrinter,
+            elementVisitorVoidType to ::VisitorVoidPrinter,
+            elementTransformerType to ::TransformerPrinter.bind(model.rootElement),
+            elementTransformerVoidType to ::TransformerVoidPrinter,
+            typeTransformerType to ::TypeTransformerPrinter.bind(model.rootElement),
+        ),
+        afterConfiguration = {
+            markLeaves(model.elements)
+        },
+        enableBaseTransformerTypeDetection = false,
+        addFiles = { add(printFactory(generationPath, model)) }
+    )
 }

compiler/ir/ir.tree/tree-generator/src/org/jetbrains/kotlin/ir/generator/print/ElementPrinter.kt

@@ -8,22 +8,19 @@ package org.jetbrains.kotlin.ir.generator.print
 import org.jetbrains.kotlin.generators.tree.*
 import org.jetbrains.kotlin.generators.tree.printer.*
 import org.jetbrains.kotlin.ir.generator.BASE_PACKAGE
-import org.jetbrains.kotlin.ir.generator.TREE_GENERATOR_README
 import org.jetbrains.kotlin.ir.generator.elementTransformerType
 import org.jetbrains.kotlin.ir.generator.elementVisitorType
 import org.jetbrains.kotlin.ir.generator.model.Element
 import org.jetbrains.kotlin.ir.generator.model.Field
 import org.jetbrains.kotlin.ir.generator.model.ListField
-import org.jetbrains.kotlin.ir.generator.model.Model
 import org.jetbrains.kotlin.ir.generator.model.SingleField
 import org.jetbrains.kotlin.utils.SmartPrinter
-import java.io.File
 import org.jetbrains.kotlin.generators.tree.ElementRef as GenericElementRef
 
 private val transformIfNeeded = ArbitraryImportable("$BASE_PACKAGE.util", "transformIfNeeded")
 private val transformInPlace = ArbitraryImportable("$BASE_PACKAGE.util", "transformInPlace")
 
-private class ElementPrinter(printer: SmartPrinter) : AbstractElementPrinter<Element, Field>(printer) {
+internal class ElementPrinter(printer: SmartPrinter) : AbstractElementPrinter<Element, Field>(printer) {
 
     override fun makeFieldPrinter(printer: SmartPrinter) = object : AbstractFieldPrinter<Field>(printer) {
         override fun forceMutable(field: Field) = field.isMutable
@@ -134,9 +131,3 @@ private class ElementPrinter(printer: SmartPrinter) : AbstractElementPrinter<Ele
         }
     }
 }
-
-fun printElements(generationPath: File, model: Model) = model.elements.map { element ->
-    printGeneratedType(generationPath, TREE_GENERATOR_README, element.packageName, element.typeName) {
-        ElementPrinter(this).printElement(element)
-    }
-}

compiler/ir/ir.tree/tree-generator/src/org/jetbrains/kotlin/ir/generator/print/TransformerPrinter.kt

@@ -6,21 +6,17 @@
 package org.jetbrains.kotlin.ir.generator.print
 
 import org.jetbrains.kotlin.generators.tree.*
-import org.jetbrains.kotlin.generators.tree.printer.GeneratedFile
 import org.jetbrains.kotlin.generators.tree.printer.printBlock
-import org.jetbrains.kotlin.ir.generator.elementTransformerType
 import org.jetbrains.kotlin.ir.generator.elementVisitorType
 import org.jetbrains.kotlin.ir.generator.model.Element
 import org.jetbrains.kotlin.ir.generator.model.Field
-import org.jetbrains.kotlin.ir.generator.model.Model
 import org.jetbrains.kotlin.utils.SmartPrinter
 import org.jetbrains.kotlin.utils.withIndent
-import java.io.File
 
-private class TransformerPrinter(
+internal class TransformerPrinter(
     printer: SmartPrinter,
     override val visitorType: ClassRef<*>,
-    val rootElement: Element,
+    private val rootElement: Element,
 ) : AbstractVisitorPrinter<Element, Field>(printer) {
 
     override val visitorSuperType: ClassRef<PositionTypeParameterRef>
@@ -62,8 +58,3 @@ private class TransformerPrinter(
         }
     }
 }
-
-fun printTransformer(generationPath: File, model: Model): GeneratedFile =
-    printVisitorCommon(generationPath, model, elementTransformerType) { printer, visitorType ->
-        TransformerPrinter(printer, visitorType, model.rootElement)
-    }

compiler/ir/ir.tree/tree-generator/src/org/jetbrains/kotlin/ir/generator/print/TransformerVoidPrinter.kt

@@ -7,19 +7,17 @@ package org.jetbrains.kotlin.ir.generator.print
 
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.generators.tree.*
-import org.jetbrains.kotlin.generators.tree.printer.*
+import org.jetbrains.kotlin.generators.tree.printer.FunctionParameter
+import org.jetbrains.kotlin.generators.tree.printer.printBlock
+import org.jetbrains.kotlin.generators.tree.printer.printFunctionWithBlockBody
 import org.jetbrains.kotlin.ir.generator.IrTree
-import org.jetbrains.kotlin.ir.generator.TREE_GENERATOR_README
 import org.jetbrains.kotlin.ir.generator.elementTransformerType
-import org.jetbrains.kotlin.ir.generator.elementTransformerVoidType
 import org.jetbrains.kotlin.ir.generator.model.Element
 import org.jetbrains.kotlin.ir.generator.model.Field
-import org.jetbrains.kotlin.ir.generator.model.Model
 import org.jetbrains.kotlin.utils.SmartPrinter
 import org.jetbrains.kotlin.utils.withIndent
-import java.io.File
 
-private class TransformerVoidPrinter(
+internal class TransformerVoidPrinter(
     printer: SmartPrinter,
     override val visitorType: ClassRef<*>,
 ) : AbstractVisitorPrinter<Element, Field>(printer) {
@@ -119,24 +117,21 @@ private class TransformerVoidPrinter(
             }
         }
     }
-}
 
-fun printTransformerVoid(generationPath: File, model: Model): GeneratedFile =
-    printGeneratedType(
-        generationPath,
-        TREE_GENERATOR_README,
-        elementTransformerVoidType.packageName,
-        elementTransformerVoidType.simpleName,
-    ) {
-        TransformerVoidPrinter(this, elementTransformerVoidType).printVisitor(model.elements)
-        println()
-        val transformerParameter = FunctionParameter("transformer", elementTransformerVoidType)
-        printFunctionWithBlockBody(
-            name = "transformChildrenVoid",
-            parameters = listOf(transformerParameter),
-            returnType = StandardTypes.unit,
-            extensionReceiver = IrTree.rootElement,
-        ) {
-            println("transformChildren(", transformerParameter.name, ", null)")
+    context(ImportCollector)
+    override fun printVisitor(elements: List<Element>) {
+        super.printVisitor(elements)
+        printer.run {
+            println()
+            val transformerParameter = FunctionParameter("transformer", visitorType)
+            printFunctionWithBlockBody(
+                name = "transformChildrenVoid",
+                parameters = listOf(transformerParameter),
+                returnType = StandardTypes.unit,
+                extensionReceiver = IrTree.rootElement,
+            ) {
+                println("transformChildren(", transformerParameter.name, ", null)")
+            }
         }
     }
+}

compiler/ir/ir.tree/tree-generator/src/org/jetbrains/kotlin/ir/generator/print/TypeTransformerPrinter.kt

@@ -7,7 +7,6 @@ package org.jetbrains.kotlin.ir.generator.print
 
 import org.jetbrains.kotlin.generators.tree.*
 import org.jetbrains.kotlin.generators.tree.printer.FunctionParameter
-import org.jetbrains.kotlin.generators.tree.printer.GeneratedFile
 import org.jetbrains.kotlin.generators.tree.printer.printBlock
 import org.jetbrains.kotlin.generators.tree.printer.printFunctionDeclaration
 import org.jetbrains.kotlin.ir.generator.IrTree
@@ -16,17 +15,14 @@ import org.jetbrains.kotlin.ir.generator.irTypeType
 import org.jetbrains.kotlin.ir.generator.model.Element
 import org.jetbrains.kotlin.ir.generator.model.Field
 import org.jetbrains.kotlin.ir.generator.model.ListField
-import org.jetbrains.kotlin.ir.generator.model.Model
 import org.jetbrains.kotlin.ir.generator.model.SingleField
-import org.jetbrains.kotlin.ir.generator.typeTransformerType
 import org.jetbrains.kotlin.utils.SmartPrinter
 import org.jetbrains.kotlin.utils.withIndent
-import java.io.File
 
-private class TypeTransformerPrinter(
+internal class TypeTransformerPrinter(
     printer: SmartPrinter,
     override val visitorType: ClassRef<*>,
-    val rootElement: Element,
+    private val rootElement: Element,
 ) : AbstractVisitorPrinter<Element, Field>(printer) {
 
     override val visitorSuperType: ClassRef<PositionTypeParameterRef>
@@ -155,8 +151,3 @@ private class TypeTransformerPrinter(
         }
     }
 }
-
-fun printTypeVisitor(generationPath: File, model: Model): GeneratedFile =
-    printVisitorCommon(generationPath, model, typeTransformerType) { printer, visitorType ->
-        TypeTransformerPrinter(printer, visitorType, model.rootElement)
-    }

compiler/ir/ir.tree/tree-generator/src/org/jetbrains/kotlin/ir/generator/print/VisitorPrinter.kt

@@ -6,14 +6,14 @@
 package org.jetbrains.kotlin.ir.generator.print
 
 import org.jetbrains.kotlin.generators.tree.*
-import org.jetbrains.kotlin.ir.generator.*
-import org.jetbrains.kotlin.ir.generator.model.*
-import org.jetbrains.kotlin.ir.generator.model.Model
+import org.jetbrains.kotlin.ir.generator.model.Element
+import org.jetbrains.kotlin.ir.generator.model.Field
 import org.jetbrains.kotlin.utils.SmartPrinter
-import java.io.File
 
-private open class VisitorPrinter(printer: SmartPrinter, override val visitorType: ClassRef<*>) :
-    AbstractVisitorPrinter<Element, Field>(printer) {
+internal class VisitorPrinter(
+    printer: SmartPrinter,
+    override val visitorType: ClassRef<*>
+) : AbstractVisitorPrinter<Element, Field>(printer) {
 
     override val visitorTypeParameters: List<TypeVariable>
         get() = listOf(resultTypeVariable, dataTypeVariable)
@@ -29,6 +29,3 @@ private open class VisitorPrinter(printer: SmartPrinter, override val visitorTyp
     override val allowTypeParametersInVisitorMethods: Boolean
         get() = false
 }
-
-fun printVisitor(generationPath: File, model: Model) = printVisitorCommon(generationPath, model, elementVisitorType, ::VisitorPrinter)
-

compiler/ir/ir.tree/tree-generator/src/org/jetbrains/kotlin/ir/generator/print/VisitorVoidPrinter.kt

@@ -9,14 +9,11 @@ import org.jetbrains.kotlin.generators.tree.AbstractVisitorVoidPrinter
 import org.jetbrains.kotlin.generators.tree.ClassRef
 import org.jetbrains.kotlin.generators.tree.PositionTypeParameterRef
 import org.jetbrains.kotlin.ir.generator.elementVisitorType
-import org.jetbrains.kotlin.ir.generator.elementVisitorVoidType
 import org.jetbrains.kotlin.ir.generator.model.Element
 import org.jetbrains.kotlin.ir.generator.model.Field
-import org.jetbrains.kotlin.ir.generator.model.Model
 import org.jetbrains.kotlin.utils.SmartPrinter
-import java.io.File
 
-private class VisitorVoidPrinter(
+internal class VisitorVoidPrinter(
     printer: SmartPrinter,
     override val visitorType: ClassRef<*>,
 ) : AbstractVisitorVoidPrinter<Element, Field>(printer) {
@@ -33,6 +30,3 @@ private class VisitorVoidPrinter(
     override val overriddenVisitMethodsAreFinal: Boolean
         get() = false
 }
-
-fun printVisitorVoid(generationPath: File, model: Model) =
-    printVisitorCommon(generationPath, model, elementVisitorVoidType, ::VisitorVoidPrinter)

compiler/ir/ir.tree/tree-generator/src/org/jetbrains/kotlin/ir/generator/print/utils.kt

@@ -5,26 +5,7 @@
 
 package org.jetbrains.kotlin.ir.generator.print
 
-import org.jetbrains.kotlin.generators.tree.AbstractVisitorPrinter
-import org.jetbrains.kotlin.generators.tree.ClassRef
-import org.jetbrains.kotlin.generators.tree.printer.GeneratedFile
-import org.jetbrains.kotlin.generators.tree.printer.printGeneratedType
-import org.jetbrains.kotlin.ir.generator.TREE_GENERATOR_README
 import org.jetbrains.kotlin.ir.generator.model.Element
-import org.jetbrains.kotlin.ir.generator.model.Field
-import org.jetbrains.kotlin.ir.generator.model.Model
-import org.jetbrains.kotlin.utils.SmartPrinter
-import java.io.File
-
-internal fun printVisitorCommon(
-    generationPath: File,
-    model: Model,
-    visitorType: ClassRef<*>,
-    makePrinter: (SmartPrinter, ClassRef<*>) -> AbstractVisitorPrinter<Element, Field>,
-): GeneratedFile =
-    printGeneratedType(generationPath, TREE_GENERATOR_README, visitorType.packageName, visitorType.simpleName) {
-        makePrinter(this, visitorType).printVisitor(model.elements)
-    }
 
 internal fun Element.getTransformExplicitType(): Element {
     return generateSequence(this) { it.parentInVisitor }

generators/tree-generator-common/src/org/jetbrains/kotlin/generators/tree/AbstractVisitorPrinter.kt

@@ -134,7 +134,7 @@ abstract class AbstractVisitorPrinter<Element : AbstractElement<Element, Field,
     }
 
     context(ImportCollector)
-    fun printVisitor(elements: List<Element>) {
+    open fun printVisitor(elements: List<Element>) {
         val visitorType = this.visitorType
         printer.run {
             printKDoc("Auto-generated by [${this@AbstractVisitorPrinter::class.qualifiedName}]")

generators/tree-generator-common/src/org/jetbrains/kotlin/generators/tree/printer/common.kt

@@ -5,7 +5,10 @@
 
 package org.jetbrains.kotlin.generators.tree.printer
 
-import org.jetbrains.kotlin.generators.tree.ImportCollector
+import org.jetbrains.kotlin.generators.tree.*
+import org.jetbrains.kotlin.generators.tree.config.AbstractBuilderConfigurator
+import org.jetbrains.kotlin.generators.tree.config.AbstractImplementationConfigurator
+import org.jetbrains.kotlin.generators.util.GeneratorsFileUtil
 import org.jetbrains.kotlin.utils.SmartPrinter
 import java.io.File
 
@@ -51,4 +54,109 @@ fun printGeneratedType(
             append(stringBuilder)
         }
     )
-}
+}
+
+/**
+ * The entry point of the tree generator.
+ *
+ * @param generationPath Where to put the generated files.
+ * @param treeGeneratorReadme A relative path to the README file of the tree generator. This path is mentioned in the auto-generation
+ * warning in each generated file.
+ * @param model The configured elements of the tree.
+ * @param pureAbstractElement The abstract class for elements that only implement interfaces to inherit from, see [addPureAbstractElement]
+ * for details.
+ * @param createElementPrinter Provide the class that prints elements, see [AbstractElementPrinter].
+ * @param createVisitorPrinters Provide the class that prints various visitors, see [AbstractVisitorPrinter].
+ * @param implementationConfigurator The class for configuring the set of implementation classes, see [AbstractImplementation] and
+ * [AbstractImplementationConfigurator].
+ * @param builderConfigurator The class for configuring the set of builders, see [Builder] and [AbstractBuilderConfigurator].
+ * @param createImplementationPrinter Provide the class that prints implementations of elements, see [AbstractImplementationPrinter].
+ * @param createBuilderPrinter Provide the class that prints the corresponding builder for each element class, see [AbstractBuilderPrinter].
+ * @param afterConfiguration The routine to run after all implementations and builders were fully configured,
+ * but before anything was printed to a file.
+ * @param enableBaseTransformerTypeDetection Whether to use a special algorithm for inferring return types of transformer methods for each
+ * element, see [detectBaseTransformerTypes].
+ * @param addFiles Arbitrary files to add to the set of generated files.
+ */
+fun <Element, Implementation, ElementField, ImplementationField> generateTree(
+    generationPath: File,
+    treeGeneratorReadme: String,
+    model: Model<Element>,
+    pureAbstractElement: ClassRef<*>,
+    createElementPrinter: (SmartPrinter) -> AbstractElementPrinter<Element, ElementField>,
+    createVisitorPrinters: List<Pair<ClassRef<*>, (SmartPrinter, ClassRef<*>) -> AbstractVisitorPrinter<Element, ElementField>>>,
+    implementationConfigurator: AbstractImplementationConfigurator<Implementation, Element, ImplementationField>? = null,
+    builderConfigurator: AbstractBuilderConfigurator<Element, Implementation, ImplementationField, ElementField>? = null,
+    createImplementationPrinter: ((SmartPrinter) -> AbstractImplementationPrinter<Implementation, Element, ImplementationField>)? = null,
+    createBuilderPrinter: ((SmartPrinter) -> AbstractBuilderPrinter<Element, Implementation, ImplementationField, ElementField>)? = null,
+    afterConfiguration: () -> Unit = {},
+    enableBaseTransformerTypeDetection: Boolean = true,
+    addFiles: MutableList<GeneratedFile>.() -> Unit = {},
+) where Element : AbstractElement<Element, ElementField, Implementation>,
+        Implementation : AbstractImplementation<Implementation, Element, ImplementationField>,
+        ElementField : AbstractField<ElementField>,
+        ImplementationField : AbstractField<*>,
+        ImplementationField : AbstractFieldWithDefaultValue<ElementField> {
+    if (enableBaseTransformerTypeDetection) {
+        detectBaseTransformerTypes(model)
+    }
+    implementationConfigurator?.configureImplementations(model)
+    val implementations = model.elements.flatMap { it.allImplementations }
+    InterfaceAndAbstractClassConfigurator((model.elements + implementations))
+        .configureInterfacesAndAbstractClasses()
+    addPureAbstractElement(model.elements, pureAbstractElement)
+    builderConfigurator?.configureBuilders()
+    afterConfiguration()
+    val generatedFiles = mutableListOf<GeneratedFile>()
+
+    model.elements.mapTo(generatedFiles) { element ->
+        printGeneratedType(
+            generationPath,
+            treeGeneratorReadme,
+            element.packageName,
+            element.typeName,
+        ) {
+            createElementPrinter(this).printElement(element)
+        }
+    }
+
+    if (createImplementationPrinter != null) {
+        implementations.mapTo(generatedFiles) { implementation ->
+            printGeneratedType(
+                generationPath,
+                treeGeneratorReadme,
+                implementation.packageName,
+                implementation.typeName,
+                fileSuppressions = listOf("DuplicatedCode", "unused"),
+            ) {
+                createImplementationPrinter(this).printImplementation(implementation)
+            }
+        }
+    }
+
+    if (createBuilderPrinter != null && builderConfigurator != null) {
+        (implementations.mapNotNull { it.builder } + builderConfigurator.intermediateBuilders).mapTo(generatedFiles) { builder ->
+            printGeneratedType(
+                generationPath,
+                treeGeneratorReadme,
+                builder.packageName,
+                builder.typeName,
+                fileSuppressions = listOf("DuplicatedCode", "unused"),
+            ) {
+                createBuilderPrinter(this).printBuilder(builder)
+            }
+        }
+    }
+
+    createVisitorPrinters.mapTo(generatedFiles) { (visitorClass, createVisitorPrinter) ->
+        printGeneratedType(generationPath, treeGeneratorReadme, visitorClass.packageName, visitorClass.simpleName) {
+            createVisitorPrinter(this, visitorClass).printVisitor(model.elements)
+        }
+    }
+
+    generatedFiles.addFiles()
+
+    val previouslyGeneratedFiles = GeneratorsFileUtil.collectPreviouslyGeneratedFiles(generationPath)
+    generatedFiles.forEach { GeneratorsFileUtil.writeFileIfContentChanged(it.file, it.newText, logNotChanged = false) }
+    GeneratorsFileUtil.removeExtraFilesFromPreviousGeneration(previouslyGeneratedFiles, generatedFiles.map { it.file })
+}

generators/tree-generator-common/src/org/jetbrains/kotlin/generators/tree/utils.kt

@@ -65,6 +65,8 @@ operator fun <K, V, U> Map<K, Map<V, U>>.get(k1: K, k2: V): U {
     return getValue(k1).getValue(k2)
 }
 
+fun <T1, T2, T3, R> ((T1, T2, T3) -> R).bind(t3: T3): ((T1, T2) -> R) = { t1, t2 -> invoke(t1, t2, t3) }
+
 internal fun <Field : AbstractField<*>> List<Field>.reorderFieldsIfNecessary(order: List<String>?): List<Field> =
     if (order == null) {
         this