[Commonizer] Split CirTreeMerger into composable 'Mergers'

2021-03-22 13:44:45 +01:00
parent 2f49e8e0af
commit 096e715652
12 changed files with 542 additions and 351 deletions
@@ -11,7 +11,6 @@ import org.jetbrains.kotlin.commonizer.ResultsConsumer.Status
 import org.jetbrains.kotlin.commonizer.core.CommonizationVisitor
 import org.jetbrains.kotlin.commonizer.mergedtree.*
 import org.jetbrains.kotlin.commonizer.mergedtree.CirNode.Companion.dimension
-import org.jetbrains.kotlin.commonizer.mergedtree.CirTreeMerger.CirTreeMergeResult
 import org.jetbrains.kotlin.commonizer.metadata.CirTreeSerializer
 import org.jetbrains.kotlin.library.SerializedMetadata
 import org.jetbrains.kotlin.storage.LockBasedStorageManager
@@ -45,11 +44,10 @@ private fun mergeAndCommonize(storageManager: StorageManager, parameters: Common
            CirProvidedClassifiers.by(parameters.dependencyModulesProvider)
        )
    )
-    val mergeResult = CirTreeMerger(storageManager, classifiers, parameters).build()
+    val mergeResult = mergeCirTree(storageManager, classifiers, parameters)

    // commonize:
-    val mergedTree = mergeResult.root
-    mergedTree.accept(CommonizationVisitor(classifiers, mergedTree), Unit)
+    mergeResult.root.accept(CommonizationVisitor(classifiers, mergeResult.root), Unit)
    parameters.progressLogger?.invoke("Commonized declarations")

    return mergeResult
@@ -5,22 +5,17 @@

 package org.jetbrains.kotlin.commonizer.mergedtree

-import com.intellij.util.containers.FactoryMap
-import kotlinx.metadata.*
-import kotlinx.metadata.klib.KlibModuleMetadata
-import kotlinx.metadata.klib.fqName
-import kotlinx.metadata.klib.klibEnumEntries
+import kotlinx.metadata.KmTypeParameter
 import org.jetbrains.kotlin.commonizer.CommonizerParameters
 import org.jetbrains.kotlin.commonizer.LeafCommonizerTarget
 import org.jetbrains.kotlin.commonizer.ModulesProvider.ModuleInfo
-import org.jetbrains.kotlin.commonizer.TargetProvider
-import org.jetbrains.kotlin.commonizer.cir.*
-import org.jetbrains.kotlin.commonizer.mergedtree.ClassesToProcess.ClassEntry
-import org.jetbrains.kotlin.commonizer.metadata.CirDeserializers
+import org.jetbrains.kotlin.commonizer.mergedtree.mergers.*
+import org.jetbrains.kotlin.commonizer.mergedtree.mergers.ClassesToProcess
+import org.jetbrains.kotlin.commonizer.mergedtree.mergers.ModuleMerger
+import org.jetbrains.kotlin.commonizer.mergedtree.mergers.PropertyMerger
+import org.jetbrains.kotlin.commonizer.mergedtree.mergers.RootMerger
+import org.jetbrains.kotlin.commonizer.mergedtree.mergers.TargetMerger
 import org.jetbrains.kotlin.commonizer.metadata.CirTypeResolver
-import org.jetbrains.kotlin.commonizer.metadata.utils.SerializedMetadataLibraryProvider
-import org.jetbrains.kotlin.commonizer.prettyName
-import org.jetbrains.kotlin.commonizer.utils.*
 import org.jetbrains.kotlin.storage.StorageManager

 /**
@@ -48,347 +43,56 @@ import org.jetbrains.kotlin.storage.StorageManager
 * targets (which is not supported yet), or a Native library where one fragment is produced via C-interop tool and the other one
 * is compiled from Kotlin/Native source code (not sure this should be supported at all).
 */
-class CirTreeMerger(
-    private val storageManager: StorageManager,
-    private val classifiers: CirKnownClassifiers,
-    private val parameters: CommonizerParameters
+
+class CirTreeMergeResult(
+    val root: CirRootNode,
+    val missingModuleInfos: Map<LeafCommonizerTarget, Collection<ModuleInfo>>
+)
+
+internal class CirTargetMergingContext(
+    val storageManager: StorageManager,
+    val classifiers: CirKnownClassifiers,
+    val parameters: CommonizerParameters,
+    val targetIndex: Int,
+    val typeResolver: CirTypeResolver
 ) {
-    class CirTreeMergeResult(
-        val root: CirRootNode,
-        val missingModuleInfos: Map<LeafCommonizerTarget, Collection<ModuleInfo>>
-    )
+    val targets = parameters.targetProviders.size
+}

-    private class CirTreeMergingContext(
-        val targetIndex: Int,
-        val typeResolver: CirTypeResolver
-    ) {
-        fun create(classEntry: ClassEntry): CirTreeMergingContext = when (classEntry) {
-            is ClassEntry.RegularClassEntry -> create(classEntry.clazz.typeParameters)
-            is ClassEntry.EnumEntry -> this
-        }
+internal fun CirTargetMergingContext.create(classEntry: ClassesToProcess.ClassEntry): CirTargetMergingContext = when (classEntry) {
+    is ClassesToProcess.ClassEntry.RegularClassEntry -> create(classEntry.clazz.typeParameters)
+    is ClassesToProcess.ClassEntry.EnumEntry -> this
+}

-        fun create(typeParameters: List<KmTypeParameter>): CirTreeMergingContext {
-            val newTypeResolver = typeResolver.create(typeParameters)
-            return if (newTypeResolver !== typeResolver)
-                CirTreeMergingContext(targetIndex, newTypeResolver)
-            else
-                this
-        }
-    }
+internal fun CirTargetMergingContext.create(typeParameters: List<KmTypeParameter>): CirTargetMergingContext {
+    val newTypeResolver = typeResolver.create(typeParameters)
+    return if (newTypeResolver !== typeResolver)
+        CirTargetMergingContext(storageManager, classifiers, parameters, targetIndex, newTypeResolver)
+    else
+        this
+}

-    private val leafTargetsSize = parameters.targetProviders.size
-
-    fun build(): CirTreeMergeResult {
-        val result = processRoot()
-        System.gc()
-        return result
-    }
-
-    private fun processRoot(): CirTreeMergeResult {
-        val rootNode: CirRootNode = buildRootNode(storageManager, leafTargetsSize)
-
-        val commonModuleNames = parameters.getCommonModuleNames()
-        val missingModuleInfosByTargets = mutableMapOf<LeafCommonizerTarget, Collection<ModuleInfo>>()
-
-        parameters.targetProviders.forEachIndexed { targetIndex, targetProvider ->
-            val allModuleInfos = targetProvider.modulesProvider.loadModuleInfos()
-
-            val (commonModuleInfos, missingModuleInfos) = allModuleInfos.partition { it.name in commonModuleNames }
-            processTarget(targetIndex, rootNode, targetProvider, commonModuleInfos)
-
-            missingModuleInfosByTargets[targetProvider.target] = missingModuleInfos
-
-            parameters.progressLogger?.invoke("Loaded declarations for ${targetProvider.target.prettyName}")
-            System.gc()
-        }
-
-        return CirTreeMergeResult(
-            root = rootNode,
-            missingModuleInfos = missingModuleInfosByTargets
-        )
-    }
-
-    private fun processTarget(
-        targetIndex: Int,
-        rootNode: CirRootNode,
-        targetProvider: TargetProvider,
-        commonModuleInfos: Collection<ModuleInfo>
-    ) {
-        rootNode.targetDeclarations[targetIndex] = CirRoot.create(targetProvider.target)
-
-        if (commonModuleInfos.isEmpty())
-            return
-
-        val context = CirTreeMergingContext(
-            targetIndex = targetIndex,
-            // all classifiers "visible" for the target:
-            typeResolver = CirTypeResolver.create(
-                providedClassifiers = CirProvidedClassifiers.of(
-                    classifiers.commonDependencies,
-                    CirProvidedClassifiers.by(targetProvider.dependencyModulesProvider),
-                    CirProvidedClassifiers.by(targetProvider.modulesProvider)
+fun mergeCirTree(
+    storageManager: StorageManager,
+    classifiers: CirKnownClassifiers,
+    parameters: CommonizerParameters
+): CirTreeMergeResult {
+    val rootMerger = RootMerger(
+        targetMerger = TargetMerger(
+            moduleMerger = ModuleMerger(
+                packageMerger = PackageMerger(
+                    propertyMerger = PropertyMerger,
+                    functionMerger = FunctionMerger,
+                    classMerger = ClassMerger(
+                        classConstructorMerger = ClassConstructorMerger,
+                        propertyMerger = PropertyMerger,
+                        functionMerger = FunctionMerger,
+                    ),
+                    typeAliasMerger = TypeAliasMerger
                )
            )
        )
+    )

-        commonModuleInfos.forEach { moduleInfo ->
-            val metadata = targetProvider.modulesProvider.loadModuleMetadata(moduleInfo.name)
-            val module = KlibModuleMetadata.read(SerializedMetadataLibraryProvider(metadata))
-            processModule(context, rootNode, module)
-        }
-    }
-
-    private fun processModule(
-        context: CirTreeMergingContext,
-        rootNode: CirRootNode,
-        module: KlibModuleMetadata
-    ) {
-        val moduleName: CirName = CirName.create(module.name)
-        val moduleNode: CirModuleNode = rootNode.modules.getOrPut(moduleName) {
-            buildModuleNode(storageManager, leafTargetsSize)
-        }
-        moduleNode.targetDeclarations[context.targetIndex] = CirModule.create(moduleName)
-
-        val groupedFragments: Map<CirPackageName, Collection<KmModuleFragment>> = module.fragments.foldToMap { fragment ->
-            fragment.fqName?.let(CirPackageName::create) ?: error("A fragment without FQ name in module $moduleName: $fragment")
-        }
-
-        groupedFragments.forEach { (packageName, fragments) ->
-            processFragments(context, moduleNode, fragments, packageName)
-        }
-    }
-
-    private fun processFragments(
-        context: CirTreeMergingContext,
-        moduleNode: CirModuleNode,
-        fragments: Collection<KmModuleFragment>,
-        packageName: CirPackageName
-    ) {
-        val packageNode: CirPackageNode = moduleNode.packages.getOrPut(packageName) {
-            buildPackageNode(storageManager, leafTargetsSize)
-        }
-        packageNode.targetDeclarations[context.targetIndex] = CirPackage.create(packageName)
-
-        val classesToProcess = ClassesToProcess()
-        fragments.forEach { fragment ->
-            classesToProcess.addClassesFromFragment(fragment)
-
-            fragment.pkg?.let { pkg ->
-                pkg.properties.forEach { property ->
-                    val propertyContext = context.create(property.typeParameters)
-                    processProperty(propertyContext, packageNode, property)
-                }
-                pkg.functions.forEach { function ->
-                    val functionContext = context.create(function.typeParameters)
-                    processFunction(functionContext, packageNode, function)
-                }
-                pkg.typeAliases.forEach { typeAlias ->
-                    val typeAliasContext = context.create(typeAlias.typeParameters)
-                    processTypeAlias(typeAliasContext, packageNode, typeAlias)
-                }
-            }
-        }
-
-        classesToProcess.forEachClassInScope(parentClassId = null) { classEntry ->
-            val classContext = context.create(classEntry)
-            processClass(classContext, packageNode, classEntry, classesToProcess)
-        }
-    }
-
-    private fun processProperty(
-        context: CirTreeMergingContext,
-        ownerNode: CirNodeWithMembers<*, *>,
-        property: KmProperty
-    ) {
-        if (property.isFakeOverride())
-            return
-
-        val maybeClassOwnerNode: CirClassNode? = ownerNode as? CirClassNode
-
-        val approximationKey = PropertyApproximationKey(property, context.typeResolver)
-        val propertyNode: CirPropertyNode = ownerNode.properties.getOrPut(approximationKey) {
-            buildPropertyNode(storageManager, leafTargetsSize, classifiers, maybeClassOwnerNode?.commonDeclaration)
-        }
-        propertyNode.targetDeclarations[context.targetIndex] = CirDeserializers.property(
-            name = approximationKey.name,
-            source = property,
-            containingClass = maybeClassOwnerNode?.targetDeclarations?.get(context.targetIndex),
-            typeResolver = context.typeResolver
-        )
-    }
-
-    private fun processFunction(
-        context: CirTreeMergingContext,
-        ownerNode: CirNodeWithMembers<*, *>,
-        function: KmFunction
-    ) {
-        if (function.isFakeOverride()
-            || function.isKniBridgeFunction()
-            || function.isTopLevelDeprecatedFunction(isTopLevel = ownerNode !is CirClassNode)
-        ) {
-            return
-        }
-
-        val maybeClassOwnerNode: CirClassNode? = ownerNode as? CirClassNode
-
-        val approximationKey = FunctionApproximationKey(function, context.typeResolver)
-        val functionNode: CirFunctionNode = ownerNode.functions.getOrPut(approximationKey) {
-            buildFunctionNode(storageManager, leafTargetsSize, classifiers, maybeClassOwnerNode?.commonDeclaration)
-        }
-        functionNode.targetDeclarations[context.targetIndex] = CirDeserializers.function(
-            name = approximationKey.name,
-            source = function,
-            containingClass = maybeClassOwnerNode?.targetDeclarations?.get(context.targetIndex),
-            typeResolver = context.typeResolver
-        )
-    }
-
-    private fun processClass(
-        context: CirTreeMergingContext,
-        ownerNode: CirNodeWithMembers<*, *>,
-        classEntry: ClassEntry,
-        classesToProcess: ClassesToProcess
-    ) {
-        val classId = classEntry.classId
-        val className = classId.relativeNameSegments.last()
-
-        val maybeClassOwnerNode: CirClassNode? = ownerNode as? CirClassNode
-        val classNode: CirClassNode = ownerNode.classes.getOrPut(className) {
-            buildClassNode(storageManager, leafTargetsSize, classifiers, maybeClassOwnerNode?.commonDeclaration, classId)
-        }
-
-        val clazz: KmClass?
-        val isEnumEntry: Boolean
-
-        classNode.targetDeclarations[context.targetIndex] = when (classEntry) {
-            is ClassEntry.RegularClassEntry -> {
-                clazz = classEntry.clazz
-                isEnumEntry = Flag.Class.IS_ENUM_ENTRY(clazz.flags)
-
-                CirDeserializers.clazz(className, clazz, context.typeResolver)
-            }
-            is ClassEntry.EnumEntry -> {
-                clazz = null
-                isEnumEntry = true
-
-                CirDeserializers.defaultEnumEntry(
-                    name = className,
-                    annotations = classEntry.annotations,
-                    enumClassId = classEntry.enumClassId,
-                    enumClass = classEntry.enumClass,
-                    typeResolver = context.typeResolver
-                )
-            }
-        }
-
-        if (!isEnumEntry) {
-            clazz?.constructors?.forEach { constructor ->
-                // TODO: nowhere to read constructor type parameters from
-                //val constructorContext = context.create(constructor.typeParameters)
-
-                processClassConstructor(context, classNode, constructor)
-            }
-        }
-
-        clazz?.properties?.forEach { property ->
-            val propertyContext = context.create(property.typeParameters)
-            processProperty(propertyContext, classNode, property)
-        }
-        clazz?.functions?.forEach { function ->
-            val functionContext = context.create(function.typeParameters)
-            processFunction(functionContext, classNode, function)
-        }
-
-        classesToProcess.forEachClassInScope(parentClassId = classId) { nestedClassEntry ->
-            val nestedClassContext = context.create(nestedClassEntry)
-            processClass(nestedClassContext, classNode, nestedClassEntry, classesToProcess)
-        }
-    }
-
-    private fun processClassConstructor(
-        context: CirTreeMergingContext,
-        classNode: CirClassNode,
-        constructor: KmConstructor
-    ) {
-        val approximationKey = ConstructorApproximationKey(constructor, context.typeResolver)
-        val constructorNode: CirClassConstructorNode = classNode.constructors.getOrPut(approximationKey) {
-            buildClassConstructorNode(storageManager, leafTargetsSize, classifiers, classNode.commonDeclaration)
-        }
-        constructorNode.targetDeclarations[context.targetIndex] = CirDeserializers.constructor(
-            source = constructor,
-            containingClass = classNode.targetDeclarations[context.targetIndex]!!,
-            typeResolver = context.typeResolver
-        )
-    }
-
-    private fun processTypeAlias(
-        context: CirTreeMergingContext,
-        packageNode: CirPackageNode,
-        typeAlias: KmTypeAlias
-    ) {
-        val typeAliasName = CirName.create(typeAlias.name)
-        val typeAliasId = CirEntityId.create(packageNode.packageName, typeAliasName)
-
-        val typeAliasNode: CirTypeAliasNode = packageNode.typeAliases.getOrPut(typeAliasName) {
-            buildTypeAliasNode(storageManager, leafTargetsSize, classifiers, typeAliasId)
-        }
-        typeAliasNode.targetDeclarations[context.targetIndex] = CirDeserializers.typeAlias(
-            name = typeAliasName,
-            source = typeAlias,
-            typeResolver = context.typeResolver
-        )
-    }
-}
-
-private class ClassesToProcess {
-    sealed class ClassEntry {
-        abstract val classId: CirEntityId
-
-        data class RegularClassEntry(
-            override val classId: CirEntityId,
-            val clazz: KmClass
-        ) : ClassEntry()
-
-        data class EnumEntry(
-            override val classId: CirEntityId,
-            val annotations: List<KmAnnotation>,
-            val enumClassId: CirEntityId,
-            val enumClass: KmClass
-        ) : ClassEntry()
-    }
-
-    // key = parent class ID (or NON_EXISTING_CLASSIFIER_ID for top-level classes)
-    // value = classes under this parent class (MutableList to preserve order of classes)
-    private val groupedByParentClassId = FactoryMap.create<CirEntityId, MutableList<ClassEntry>> { ArrayList() }
-
-    fun addClassesFromFragment(fragment: KmModuleFragment) {
-        val klibEnumEntries = LinkedHashMap<CirEntityId, ClassEntry.EnumEntry>() // linked hash map to preserve order
-        val regularClassIds = HashSet<CirEntityId>()
-
-        fragment.classes.forEach { clazz ->
-            val classId: CirEntityId = CirEntityId.create(clazz.name)
-            val parentClassId: CirEntityId = classId.getParentEntityId() ?: NON_EXISTING_CLASSIFIER_ID
-
-            if (Flag.Class.IS_ENUM_CLASS(clazz.flags)) {
-                clazz.klibEnumEntries.forEach { entry ->
-                    val enumEntryId = classId.createNestedEntityId(CirName.create(entry.name))
-                    klibEnumEntries[enumEntryId] = ClassEntry.EnumEntry(enumEntryId, entry.annotations, classId, clazz)
-                }
-            }
-
-            groupedByParentClassId.getValue(parentClassId) += ClassEntry.RegularClassEntry(classId, clazz)
-            regularClassIds += classId
-        }
-
-        // add enum entries that are not stored in module as KmClass records
-        klibEnumEntries.forEach { (enumEntryId, enumEntry) ->
-            if (enumEntryId !in regularClassIds) {
-                groupedByParentClassId.getValue(enumEntry.enumClassId) += enumEntry
-            }
-        }
-    }
-
-    fun forEachClassInScope(parentClassId: CirEntityId?, block: (ClassEntry) -> Unit) {
-        groupedByParentClassId[parentClassId ?: NON_EXISTING_CLASSIFIER_ID]?.forEach { classEntry -> block(classEntry) }
-    }
+    return rootMerger.processRoot(storageManager, classifiers, parameters)
 }
@@ -0,0 +1,30 @@
+/*
+ * Copyright 2010-2021 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.commonizer.mergedtree.mergers
+
+import kotlinx.metadata.KmConstructor
+import org.jetbrains.kotlin.commonizer.mergedtree.*
+import org.jetbrains.kotlin.commonizer.mergedtree.CirTargetMergingContext
+import org.jetbrains.kotlin.commonizer.mergedtree.buildClassConstructorNode
+import org.jetbrains.kotlin.commonizer.metadata.CirDeserializers
+
+internal object ClassConstructorMerger {
+    fun processClassConstructor(
+        context: CirTargetMergingContext,
+        classNode: CirClassNode,
+        constructor: KmConstructor
+    ) = with(context) {
+        val approximationKey = ConstructorApproximationKey(constructor, context.typeResolver)
+        val constructorNode: CirClassConstructorNode = classNode.constructors.getOrPut(approximationKey) {
+            buildClassConstructorNode(storageManager, targets, classifiers, classNode.commonDeclaration)
+        }
+        constructorNode.targetDeclarations[context.targetIndex] = CirDeserializers.constructor(
+            source = constructor,
+            containingClass = classNode.targetDeclarations[context.targetIndex]!!,
+            typeResolver = context.typeResolver
+        )
+    }
+}
@@ -0,0 +1,80 @@
+/*
+ * Copyright 2010-2021 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.commonizer.mergedtree.mergers
+
+import kotlinx.metadata.Flag
+import kotlinx.metadata.KmClass
+import org.jetbrains.kotlin.commonizer.mergedtree.*
+import org.jetbrains.kotlin.commonizer.mergedtree.CirTargetMergingContext
+import org.jetbrains.kotlin.commonizer.mergedtree.buildClassNode
+import org.jetbrains.kotlin.commonizer.metadata.CirDeserializers
+
+internal class ClassMerger(
+    private val classConstructorMerger: ClassConstructorMerger?,
+    private val propertyMerger: PropertyMerger?,
+    private val functionMerger: FunctionMerger?
+) {
+    fun processClass(
+        context: CirTargetMergingContext,
+        ownerNode: CirNodeWithMembers<*, *>,
+        classEntry: ClassesToProcess.ClassEntry,
+        classesToProcess: ClassesToProcess
+    ): Unit = with(context) {
+        val classId = classEntry.classId
+        val className = classId.relativeNameSegments.last()
+
+        val maybeClassOwnerNode: CirClassNode? = ownerNode as? CirClassNode
+        val classNode: CirClassNode = ownerNode.classes.getOrPut(className) {
+            buildClassNode(storageManager, targets, classifiers, maybeClassOwnerNode?.commonDeclaration, classId)
+        }
+
+        val clazz: KmClass?
+        val isEnumEntry: Boolean
+
+        classNode.targetDeclarations[context.targetIndex] = when (classEntry) {
+            is ClassesToProcess.ClassEntry.RegularClassEntry -> {
+                clazz = classEntry.clazz
+                isEnumEntry = Flag.Class.IS_ENUM_ENTRY(clazz.flags)
+
+                CirDeserializers.clazz(className, clazz, context.typeResolver)
+            }
+            is ClassesToProcess.ClassEntry.EnumEntry -> {
+                clazz = null
+                isEnumEntry = true
+
+                CirDeserializers.defaultEnumEntry(
+                    name = className,
+                    annotations = classEntry.annotations,
+                    enumClassId = classEntry.enumClassId,
+                    enumClass = classEntry.enumClass,
+                    typeResolver = context.typeResolver
+                )
+            }
+        }
+
+        if (!isEnumEntry) {
+            clazz?.constructors?.forEach { constructor ->
+                // TODO: nowhere to read constructor type parameters from
+                //val constructorContext = context.create(constructor.typeParameters)
+                classConstructorMerger?.processClassConstructor(context, classNode, constructor)
+            }
+        }
+
+        clazz?.properties?.forEach { property ->
+            val propertyContext = context.create(property.typeParameters)
+            propertyMerger?.processProperty(propertyContext, classNode, property)
+        }
+        clazz?.functions?.forEach { function ->
+            val functionContext = context.create(function.typeParameters)
+            functionMerger?.processFunction(functionContext, classNode, function)
+        }
+
+        classesToProcess.forEachClassInScope(parentClassId = classId) { nestedClassEntry ->
+            val nestedClassContext = context.create(nestedClassEntry)
+            processClass(nestedClassContext, classNode, nestedClassEntry, classesToProcess)
+        }
+    }
+}
@@ -0,0 +1,69 @@
+/*
+ * Copyright 2010-2021 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.commonizer.mergedtree.mergers
+
+import com.intellij.util.containers.FactoryMap
+import kotlinx.metadata.Flag
+import kotlinx.metadata.KmAnnotation
+import kotlinx.metadata.KmClass
+import kotlinx.metadata.KmModuleFragment
+import kotlinx.metadata.klib.klibEnumEntries
+import org.jetbrains.kotlin.commonizer.cir.CirEntityId
+import org.jetbrains.kotlin.commonizer.cir.CirName
+import org.jetbrains.kotlin.commonizer.utils.NON_EXISTING_CLASSIFIER_ID
+
+internal class ClassesToProcess {
+    sealed class ClassEntry {
+        abstract val classId: CirEntityId
+
+        data class RegularClassEntry(
+            override val classId: CirEntityId,
+            val clazz: KmClass
+        ) : ClassEntry()
+
+        data class EnumEntry(
+            override val classId: CirEntityId,
+            val annotations: List<KmAnnotation>,
+            val enumClassId: CirEntityId,
+            val enumClass: KmClass
+        ) : ClassEntry()
+    }
+
+    // key = parent class ID (or NON_EXISTING_CLASSIFIER_ID for top-level classes)
+    // value = classes under this parent class (MutableList to preserve order of classes)
+    private val groupedByParentClassId = FactoryMap.create<CirEntityId, MutableList<ClassEntry>> { ArrayList() }
+
+    fun addClassesFromFragment(fragment: KmModuleFragment) {
+        val klibEnumEntries = LinkedHashMap<CirEntityId, ClassEntry.EnumEntry>() // linked hash map to preserve order
+        val regularClassIds = HashSet<CirEntityId>()
+
+        fragment.classes.forEach { clazz ->
+            val classId: CirEntityId = CirEntityId.create(clazz.name)
+            val parentClassId: CirEntityId = classId.getParentEntityId() ?: NON_EXISTING_CLASSIFIER_ID
+
+            if (Flag.Class.IS_ENUM_CLASS(clazz.flags)) {
+                clazz.klibEnumEntries.forEach { entry ->
+                    val enumEntryId = classId.createNestedEntityId(CirName.create(entry.name))
+                    klibEnumEntries[enumEntryId] = ClassEntry.EnumEntry(enumEntryId, entry.annotations, classId, clazz)
+                }
+            }
+
+            groupedByParentClassId.getValue(parentClassId) += ClassEntry.RegularClassEntry(classId, clazz)
+            regularClassIds += classId
+        }
+
+        // add enum entries that are not stored in module as KmClass records
+        klibEnumEntries.forEach { (enumEntryId, enumEntry) ->
+            if (enumEntryId !in regularClassIds) {
+                groupedByParentClassId.getValue(enumEntry.enumClassId) += enumEntry
+            }
+        }
+    }
+
+    fun forEachClassInScope(parentClassId: CirEntityId?, block: (ClassEntry) -> Unit) {
+        groupedByParentClassId[parentClassId ?: NON_EXISTING_CLASSIFIER_ID]?.forEach { classEntry -> block(classEntry) }
+    }
+}
@@ -0,0 +1,43 @@
+/*
+ * Copyright 2010-2021 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.commonizer.mergedtree.mergers
+
+import kotlinx.metadata.KmFunction
+import org.jetbrains.kotlin.commonizer.mergedtree.*
+import org.jetbrains.kotlin.commonizer.mergedtree.CirTargetMergingContext
+import org.jetbrains.kotlin.commonizer.mergedtree.buildFunctionNode
+import org.jetbrains.kotlin.commonizer.metadata.CirDeserializers
+import org.jetbrains.kotlin.commonizer.utils.isFakeOverride
+import org.jetbrains.kotlin.commonizer.utils.isKniBridgeFunction
+import org.jetbrains.kotlin.commonizer.utils.isTopLevelDeprecatedFunction
+
+internal object FunctionMerger {
+    fun processFunction(
+        context: CirTargetMergingContext,
+        ownerNode: CirNodeWithMembers<*, *>,
+        function: KmFunction
+    ) = with(context) {
+        if (function.isFakeOverride()
+            || function.isKniBridgeFunction()
+            || function.isTopLevelDeprecatedFunction(isTopLevel = ownerNode !is CirClassNode)
+        ) {
+            return
+        }
+
+        val maybeClassOwnerNode: CirClassNode? = ownerNode as? CirClassNode
+
+        val approximationKey = FunctionApproximationKey(function, context.typeResolver)
+        val functionNode: CirFunctionNode = ownerNode.functions.getOrPut(approximationKey) {
+            buildFunctionNode(storageManager, targets, classifiers, maybeClassOwnerNode?.commonDeclaration)
+        }
+        functionNode.targetDeclarations[context.targetIndex] = CirDeserializers.function(
+            name = approximationKey.name,
+            source = function,
+            containingClass = maybeClassOwnerNode?.targetDeclarations?.get(context.targetIndex),
+            typeResolver = context.typeResolver
+        )
+    }
+}
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2010-2021 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.commonizer.mergedtree.mergers
+
+import kotlinx.metadata.KmModuleFragment
+import kotlinx.metadata.klib.KlibModuleMetadata
+import kotlinx.metadata.klib.fqName
+import org.jetbrains.kotlin.commonizer.cir.CirModule
+import org.jetbrains.kotlin.commonizer.cir.CirName
+import org.jetbrains.kotlin.commonizer.cir.CirPackageName
+import org.jetbrains.kotlin.commonizer.mergedtree.CirModuleNode
+import org.jetbrains.kotlin.commonizer.mergedtree.CirRootNode
+import org.jetbrains.kotlin.commonizer.mergedtree.CirTargetMergingContext
+import org.jetbrains.kotlin.commonizer.mergedtree.buildModuleNode
+import org.jetbrains.kotlin.commonizer.utils.foldToMap
+
+internal class ModuleMerger(
+    private val packageMerger: PackageMerger
+) {
+    fun processModule(
+        context: CirTargetMergingContext,
+        rootNode: CirRootNode,
+        module: KlibModuleMetadata
+    ): Unit = with(context) {
+        val moduleName: CirName = CirName.create(module.name)
+        val moduleNode: CirModuleNode = rootNode.modules.getOrPut(moduleName) {
+            buildModuleNode(storageManager, targets)
+        }
+        moduleNode.targetDeclarations[context.targetIndex] = CirModule.create(moduleName)
+
+        val groupedFragments: Map<CirPackageName, Collection<KmModuleFragment>> = module.fragments.foldToMap { fragment ->
+            fragment.fqName?.let(CirPackageName.Companion::create) ?: error("A fragment without FQ name in module $moduleName: $fragment")
+        }
+
+        groupedFragments.forEach { (packageName, fragments) ->
+            packageMerger.processFragments(context, moduleNode, fragments, packageName)
+        }
+    }
+}
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2010-2021 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.commonizer.mergedtree.mergers
+
+import kotlinx.metadata.KmModuleFragment
+import kotlinx.metadata.KmTypeParameter
+import org.jetbrains.kotlin.commonizer.cir.CirPackage
+import org.jetbrains.kotlin.commonizer.cir.CirPackageName
+import org.jetbrains.kotlin.commonizer.mergedtree.*
+import org.jetbrains.kotlin.commonizer.mergedtree.CirTargetMergingContext
+import org.jetbrains.kotlin.commonizer.mergedtree.buildPackageNode
+
+internal class PackageMerger(
+    private val propertyMerger: PropertyMerger?,
+    private val functionMerger: FunctionMerger?,
+    private val classMerger: ClassMerger?,
+    private val typeAliasMerger: TypeAliasMerger?
+) {
+    fun processFragments(
+        context: CirTargetMergingContext,
+        moduleNode: CirModuleNode,
+        fragments: Collection<KmModuleFragment>,
+        packageName: CirPackageName
+    ): Unit = with(context) {
+        val packageNode: CirPackageNode = moduleNode.packages.getOrPut(packageName) {
+            buildPackageNode(storageManager, targets)
+        }
+        packageNode.targetDeclarations[context.targetIndex] = CirPackage.create(packageName)
+
+        val classesToProcess = ClassesToProcess()
+        fragments.forEach { fragment ->
+            classesToProcess.addClassesFromFragment(fragment)
+
+            fragment.pkg?.let { pkg ->
+                pkg.properties.forEach { property ->
+                    val propertyContext = context.create(property.typeParameters)
+                    propertyMerger?.processProperty(propertyContext, packageNode, property)
+                }
+                pkg.functions.forEach { function ->
+                    val functionContext = context.create(function.typeParameters)
+                    functionMerger?.processFunction(functionContext, packageNode, function)
+                }
+                pkg.typeAliases.forEach { typeAlias ->
+                    val typeAliasContext = context.create(typeAlias.typeParameters)
+                    typeAliasMerger?.processTypeAlias(typeAliasContext, packageNode, typeAlias)
+                }
+            }
+        }
+
+        classesToProcess.forEachClassInScope(parentClassId = null) { classEntry ->
+            val classContext = context.create(classEntry)
+            classMerger?.processClass(classContext, packageNode, classEntry, classesToProcess)
+        }
+    }
+}
@@ -0,0 +1,37 @@
+/*
+ * Copyright 2010-2021 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.commonizer.mergedtree.mergers
+
+import kotlinx.metadata.KmProperty
+import org.jetbrains.kotlin.commonizer.mergedtree.*
+import org.jetbrains.kotlin.commonizer.mergedtree.CirTargetMergingContext
+import org.jetbrains.kotlin.commonizer.mergedtree.buildPropertyNode
+import org.jetbrains.kotlin.commonizer.metadata.CirDeserializers
+import org.jetbrains.kotlin.commonizer.utils.isFakeOverride
+
+internal object PropertyMerger {
+    fun processProperty(
+        context: CirTargetMergingContext,
+        ownerNode: CirNodeWithMembers<*, *>,
+        property: KmProperty
+    ) = with(context) {
+        if (property.isFakeOverride())
+            return
+
+        val maybeClassOwnerNode: CirClassNode? = ownerNode as? CirClassNode
+
+        val approximationKey = PropertyApproximationKey(property, context.typeResolver)
+        val propertyNode: CirPropertyNode = ownerNode.properties.getOrPut(approximationKey) {
+            buildPropertyNode(storageManager, targets, classifiers, maybeClassOwnerNode?.commonDeclaration)
+        }
+        propertyNode.targetDeclarations[context.targetIndex] = CirDeserializers.property(
+            name = approximationKey.name,
+            source = property,
+            containingClass = maybeClassOwnerNode?.targetDeclarations?.get(context.targetIndex),
+            typeResolver = context.typeResolver
+        )
+    }
+}
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2010-2021 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.commonizer.mergedtree.mergers
+
+import org.jetbrains.kotlin.commonizer.CommonizerParameters
+import org.jetbrains.kotlin.commonizer.LeafCommonizerTarget
+import org.jetbrains.kotlin.commonizer.ModulesProvider
+import org.jetbrains.kotlin.commonizer.mergedtree.*
+import org.jetbrains.kotlin.commonizer.mergedtree.buildRootNode
+import org.jetbrains.kotlin.commonizer.metadata.CirTypeResolver
+import org.jetbrains.kotlin.commonizer.prettyName
+import org.jetbrains.kotlin.storage.StorageManager
+
+internal class RootMerger(
+    private val targetMerger: TargetMerger
+) {
+    fun processRoot(
+        storageManager: StorageManager,
+        classifiers: CirKnownClassifiers,
+        parameters: CommonizerParameters
+    ): CirTreeMergeResult {
+        val rootNode: CirRootNode = buildRootNode(storageManager, parameters.targetProviders.size)
+
+        val commonModuleNames = parameters.getCommonModuleNames()
+        val missingModuleInfosByTargets = mutableMapOf<LeafCommonizerTarget, Collection<ModulesProvider.ModuleInfo>>()
+
+        parameters.targetProviders.forEachIndexed { targetIndex, targetProvider ->
+            val allModuleInfos = targetProvider.modulesProvider.loadModuleInfos()
+
+            val (commonModuleInfos, missingModuleInfos) = allModuleInfos.partition { it.name in commonModuleNames }
+            val typeResolver = CirTypeResolver.create(
+                providedClassifiers = CirProvidedClassifiers.of(
+                    classifiers.commonDependencies,
+                    CirProvidedClassifiers.by(targetProvider.dependencyModulesProvider),
+                    CirProvidedClassifiers.by(targetProvider.modulesProvider)
+                )
+            )
+            targetMerger.processTarget(
+                CirTargetMergingContext(
+                    storageManager, classifiers, parameters, targetIndex, typeResolver
+                ), rootNode, targetProvider, commonModuleInfos
+            )
+
+            missingModuleInfosByTargets[targetProvider.target] = missingModuleInfos
+
+            parameters.progressLogger?.invoke("Loaded declarations for ${targetProvider.target.prettyName}")
+            System.gc()
+        }
+
+        return CirTreeMergeResult(
+            root = rootNode,
+            missingModuleInfos = missingModuleInfosByTargets
+        )
+    }
+}
@@ -0,0 +1,37 @@
+/*
+ * Copyright 2010-2021 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.commonizer.mergedtree.mergers
+
+import kotlinx.metadata.klib.KlibModuleMetadata
+import org.jetbrains.kotlin.commonizer.ModulesProvider
+import org.jetbrains.kotlin.commonizer.TargetProvider
+import org.jetbrains.kotlin.commonizer.cir.CirRoot
+import org.jetbrains.kotlin.commonizer.mergedtree.CirRootNode
+import org.jetbrains.kotlin.commonizer.mergedtree.CirTargetMergingContext
+import org.jetbrains.kotlin.commonizer.metadata.utils.SerializedMetadataLibraryProvider
+
+internal class TargetMerger(
+    private val moduleMerger: ModuleMerger
+) {
+    fun processTarget(
+        context: CirTargetMergingContext,
+        rootNode: CirRootNode,
+        targetProvider: TargetProvider,
+        commonModuleInfos: Collection<ModulesProvider.ModuleInfo>
+    ): Unit = with(context) {
+        rootNode.targetDeclarations[targetIndex] = CirRoot.create(targetProvider.target)
+
+        if (commonModuleInfos.isEmpty()) {
+            return
+        }
+
+        commonModuleInfos.forEach { moduleInfo ->
+            val metadata = targetProvider.modulesProvider.loadModuleMetadata(moduleInfo.name)
+            val module = KlibModuleMetadata.read(SerializedMetadataLibraryProvider(metadata))
+            moduleMerger.processModule(context, rootNode, module)
+        }
+    }
+}
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2010-2021 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.commonizer.mergedtree.mergers
+
+import kotlinx.metadata.KmTypeAlias
+import org.jetbrains.kotlin.commonizer.cir.CirEntityId
+import org.jetbrains.kotlin.commonizer.cir.CirName
+import org.jetbrains.kotlin.commonizer.mergedtree.CirPackageNode
+import org.jetbrains.kotlin.commonizer.mergedtree.CirTargetMergingContext
+import org.jetbrains.kotlin.commonizer.mergedtree.CirTypeAliasNode
+import org.jetbrains.kotlin.commonizer.mergedtree.buildTypeAliasNode
+import org.jetbrains.kotlin.commonizer.metadata.CirDeserializers
+
+internal object TypeAliasMerger {
+    fun processTypeAlias(
+        context: CirTargetMergingContext,
+        packageNode: CirPackageNode,
+        typeAlias: KmTypeAlias
+    ) = with(context) {
+        val typeAliasName = CirName.create(typeAlias.name)
+        val typeAliasId = CirEntityId.create(packageNode.packageName, typeAliasName)
+
+        val typeAliasNode: CirTypeAliasNode = packageNode.typeAliases.getOrPut(typeAliasName) {
+            buildTypeAliasNode(storageManager, targets, classifiers, typeAliasId)
+        }
+        typeAliasNode.targetDeclarations[context.targetIndex] = CirDeserializers.typeAlias(
+            name = typeAliasName,
+            source = typeAlias,
+            typeResolver = context.typeResolver
+        )
+    }
+}