[Commonizer] Don't keep references to descriptor objects when they are not needed anymore

This is necessary to reduce overall memory consumption.

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/CommonizationParameters.kt

@@ -1,42 +0,0 @@
-/*
- * Copyright 2010-2019 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.descriptors.commonizer
-
-import org.jetbrains.kotlin.descriptors.ModuleDescriptor
-
-class CommonizationParameters(
-    val statsCollector: StatsCollector? = null
-) {
-    // use linked hash map to preserve order
-    private val modulesByTargets = LinkedHashMap<InputTarget, Collection<ModuleDescriptor>>()
-
-    fun addTarget(target: InputTarget, modules: Collection<ModuleDescriptor>): CommonizationParameters {
-        require(target !in modulesByTargets) { "Target $target is already added" }
-
-        val modulesWithUniqueNames = modules.groupingBy { it.name }.eachCount()
-        require(modulesWithUniqueNames.size == modules.size) {
-            "Modules with duplicated names found: ${modulesWithUniqueNames.filter { it.value > 1 }}"
-        }
-
-        modulesByTargets[target] = modules
-
-        return this
-    }
-
-    // get them as ordered immutable collection (List) for further processing
-    fun getModulesByTargets(): List<Pair<InputTarget, Collection<ModuleDescriptor>>> =
-        modulesByTargets.map { it.key to it.value }
-
-    fun hasIntersection(): Boolean {
-        if (modulesByTargets.size < 2)
-            return false
-
-        return modulesByTargets.flatMap { it.value }
-            .groupingBy { it.name }
-            .eachCount()
-            .any { it.value == modulesByTargets.size }
-    }
-}

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/Parameters.kt

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2010-2019 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.descriptors.commonizer
+
+class Parameters(
+    val statsCollector: StatsCollector? = null
+) {
+    // use linked hash map to preserve order
+    private val _targetProviders = LinkedHashMap<InputTarget, TargetProvider>()
+
+    val targetProviders: List<TargetProvider> get() = _targetProviders.values.toList()
+
+    fun addTarget(targetProvider: TargetProvider): Parameters {
+        require(targetProvider.target !in _targetProviders) { "Target ${targetProvider.target} is already added" }
+        _targetProviders[targetProvider.target] = targetProvider
+
+        return this
+    }
+
+    fun hasAnythingToCommonize(): Boolean = _targetProviders.size >= 2
+}

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/Result.kt

@@ -7,13 +7,13 @@ package org.jetbrains.kotlin.descriptors.commonizer
 
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 
-sealed class CommonizationResult
+sealed class Result
 
-object NothingToCommonize : CommonizationResult()
+object NothingToCommonize : Result()
 
 class CommonizationPerformed(
     val modulesByTargets: Map<Target, Collection<ModuleDescriptor>>
-) : CommonizationResult() {
+) : Result() {
     val commonTarget: OutputTarget by lazy {
         modulesByTargets.keys.filterIsInstance<OutputTarget>().single()
     }

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/TargetProvider.kt

@@ -0,0 +1,38 @@
+/*
+ * 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.descriptors.commonizer
+
+import org.jetbrains.kotlin.builtins.KotlinBuiltIns
+import org.jetbrains.kotlin.descriptors.ModuleDescriptor
+
+class TargetProvider(
+    val target: InputTarget,
+    val builtInsClass: Class<out KotlinBuiltIns>,
+    val builtInsProvider: BuiltInsProvider,
+    val modulesProvider: ModulesProvider
+)
+
+interface BuiltInsProvider {
+    fun loadBuiltIns(): KotlinBuiltIns
+
+    companion object {
+        fun wrap(builtIns: KotlinBuiltIns) = object : BuiltInsProvider {
+            override fun loadBuiltIns() = builtIns
+        }
+    }
+}
+
+interface ModulesProvider {
+    fun loadModules(): Collection<ModuleDescriptor>
+
+    companion object {
+        fun wrap(modules: Collection<ModuleDescriptor>) = object : ModulesProvider {
+            override fun loadModules() = modules
+        }
+
+        fun wrap(vararg modules: ModuleDescriptor) = wrap(modules.toList())
+    }
+}

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/builder/DeclarationsBuilderVisitor1.kt

@@ -29,7 +29,7 @@ internal class DeclarationsBuilderVisitor1(
         check(data.isEmpty()) // root node may not have containing declarations
         check(components.targetComponents.size == node.dimension)
 
-        val allTargets = (node.target + node.common()!!).map { it.target }
+        val allTargets = (node.target + node.common()!!).map { it!!.target }
 
         val modulesByTargets = HashMap<Target, MutableList<ModuleDescriptorImpl>>()
 

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/builder/context.kt

@@ -154,16 +154,16 @@ fun CirRootNode.createGlobalBuilderComponents(
 
     val targetContexts = (0 until dimension).map { index ->
         val isCommon = index == indexOfCommon
-        val target = (if (isCommon) common()!! else target[index]).target
+        val root = if (isCommon) common()!! else target[index]!!
 
-        val builtIns = modules.asSequence()
+        val builtIns = root.builtInsProvider.loadBuiltIns()
-            .mapNotNull { if (isCommon) it.common() else it.target[index] }
+        check(builtIns::class.java.name == root.builtInsClass) {
-            .first()
+            "Unexpected built-ins class: ${builtIns::class.java}, $builtIns\nExpected: ${root.builtInsClass}"
-            .builtIns
+        }
 
         TargetDeclarationsBuilderComponents(
             storageManager = storageManager,
-            target = target,
+            target = root.target,
             builtIns = builtIns,
             isCommon = isCommon,
             index = index,

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/builder/moduleDescriptors.kt

@@ -33,7 +33,7 @@ private fun CirModule.buildDescriptor(
     val moduleDescriptor = ModuleDescriptorImpl(
         moduleName = name,
         storageManager = components.storageManager,
-        builtIns = builtIns,
+        builtIns = components.targetComponents[index].builtIns,
         capabilities = emptyMap() // TODO: preserve capabilities from the original module descriptors, KT-33998
     )
 

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/core/ModuleCommonizer.kt

@@ -5,8 +5,6 @@
 
 package org.jetbrains.kotlin.descriptors.commonizer.core
 
-import org.jetbrains.kotlin.builtins.DefaultBuiltIns
-import org.jetbrains.kotlin.builtins.konan.KonanBuiltIns
 import org.jetbrains.kotlin.descriptors.commonizer.mergedtree.ir.CirModule
 import org.jetbrains.kotlin.name.Name
 
@@ -18,28 +16,12 @@ interface ModuleCommonizer : Commonizer<CirModule, CirModule> {
 
 private class DefaultModuleCommonizer : ModuleCommonizer, AbstractStandardCommonizer<CirModule, CirModule>() {
     private lateinit var name: Name
-    private var konanBuiltIns: KonanBuiltIns? = null
 
-    override fun commonizationResult() = CirModule(
+    override fun commonizationResult() = CirModule(name = name)
-        name = name,
-        builtIns = konanBuiltIns ?: DefaultBuiltIns.Instance
-    )
 
     override fun initialize(first: CirModule) {
         name = first.name
-        konanBuiltIns = first.konanBuiltIns
     }
 
-    override fun doCommonizeWith(next: CirModule): Boolean {
+    override fun doCommonizeWith(next: CirModule) = true
-        // keep the first met KonanBuiltIns when all targets are Kotlin/Native
-        // otherwise use DefaultBuiltIns
-        if (konanBuiltIns != null) {
-            konanBuiltIns = konanBuiltIns.takeIf { next.konanBuiltIns != null }
-        }
-
-        return true
-    }
-
-    private inline val CirModule.konanBuiltIns
-        get() = builtIns as? KonanBuiltIns
 }

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/core/RootCommonizer.kt

@@ -0,0 +1,50 @@
+/*
+ * 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.descriptors.commonizer.core
+
+import org.jetbrains.kotlin.builtins.DefaultBuiltIns
+import org.jetbrains.kotlin.builtins.konan.KonanBuiltIns
+import org.jetbrains.kotlin.descriptors.commonizer.BuiltInsProvider
+import org.jetbrains.kotlin.descriptors.commonizer.InputTarget
+import org.jetbrains.kotlin.descriptors.commonizer.OutputTarget
+import org.jetbrains.kotlin.descriptors.commonizer.mergedtree.ir.CirRoot
+
+interface RootCommonizer : Commonizer<CirRoot, CirRoot> {
+    companion object {
+        fun default(): RootCommonizer = DefaultRootCommonizer()
+    }
+}
+
+private class DefaultRootCommonizer : RootCommonizer, AbstractStandardCommonizer<CirRoot, CirRoot>() {
+    private val inputTargets = mutableSetOf<InputTarget>()
+    private var konanBuiltInsProvider: BuiltInsProvider? = null
+
+    override fun commonizationResult() = CirRoot(
+        target = OutputTarget(inputTargets),
+        builtInsClass = if (konanBuiltInsProvider != null) KonanBuiltIns::class.java.name else DefaultBuiltIns::class.java.name,
+        builtInsProvider = konanBuiltInsProvider ?: BuiltInsProvider.wrap(DefaultBuiltIns.Instance)
+    )
+
+    override fun initialize(first: CirRoot) {
+        inputTargets += first.target as InputTarget
+        konanBuiltInsProvider = first.konanBuiltInsProvider
+    }
+
+    override fun doCommonizeWith(next: CirRoot): Boolean {
+        inputTargets += next.target as InputTarget
+
+        // keep the first met KonanBuiltIns when all targets are Kotlin/Native
+        // otherwise use DefaultBuiltIns
+        if (konanBuiltInsProvider != null && next.konanBuiltInsProvider == null) {
+            konanBuiltInsProvider = null
+        }
+
+        return true
+    }
+
+    private inline val CirRoot.konanBuiltInsProvider
+        get() = if (builtInsClass == KonanBuiltIns::class.java.name) builtInsProvider else null
+}

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/facade.kt

@@ -13,14 +13,14 @@ import org.jetbrains.kotlin.descriptors.commonizer.core.CommonizationVisitor
 import org.jetbrains.kotlin.descriptors.commonizer.mergedtree.mergeRoots
 import org.jetbrains.kotlin.storage.LockBasedStorageManager
 
-fun runCommonization(parameters: CommonizationParameters): CommonizationResult {
+fun runCommonization(parameters: Parameters): Result {
-    if (!parameters.hasIntersection())
+    if (!parameters.hasAnythingToCommonize())
         return NothingToCommonize
 
     val storageManager = LockBasedStorageManager("Declaration descriptors commonization")
 
     // build merged tree:
-    val mergedTree = mergeRoots(storageManager, parameters.getModulesByTargets())
+    val mergedTree = mergeRoots(storageManager, parameters.targetProviders)
 
     // commonize:
     mergedTree.accept(CommonizationVisitor(mergedTree), Unit)

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/konan/NativeDistributionCommonizer.kt

@@ -8,14 +8,11 @@ package org.jetbrains.kotlin.descriptors.commonizer.konan
 import org.jetbrains.kotlin.backend.common.serialization.metadata.KlibMetadataMonolithicSerializer
 import org.jetbrains.kotlin.backend.common.serialization.metadata.KlibMetadataVersion
 import org.jetbrains.kotlin.backend.common.serialization.metadata.metadataVersion
+import org.jetbrains.kotlin.builtins.konan.KonanBuiltIns
 import org.jetbrains.kotlin.config.LanguageVersionSettingsImpl
 import org.jetbrains.kotlin.descriptors.commonizer.*
 import org.jetbrains.kotlin.descriptors.commonizer.Target
-import org.jetbrains.kotlin.descriptors.commonizer.konan.NativeModuleForCommonization.DeserializedModule
-import org.jetbrains.kotlin.descriptors.commonizer.konan.NativeModuleForCommonization.SyntheticModule
-import org.jetbrains.kotlin.descriptors.commonizer.utils.NativeFactories.DefaultDeserializedDescriptorFactory
 import org.jetbrains.kotlin.descriptors.commonizer.utils.ResettableClockMark
-import org.jetbrains.kotlin.descriptors.commonizer.utils.createKotlinNativeForwardDeclarationsModule
 import org.jetbrains.kotlin.konan.library.*
 import org.jetbrains.kotlin.konan.target.KonanTarget
 import org.jetbrains.kotlin.library.KotlinLibrary
@@ -44,16 +41,16 @@ class NativeDistributionCommonizer(
         checkPreconditions()
 
         with(ResettableClockMark()) {
-            // 1. load modules
+            // 1. load libraries
-            val modulesByTargets = loadModules()
+            val librariesByTargets = loadLibraries()
             logger.log("* Loaded lazy (uninitialized) libraries in ${elapsedSinceLast()}")
 
             // 2. run commonization
-            val result = commonize(modulesByTargets)
+            val result = commonize(librariesByTargets)
             logger.log("* Commonization performed in ${elapsedSinceLast()}")
 
             // 3. write new libraries
-            saveModules(modulesByTargets, result)
+            saveModules(librariesByTargets, result)
             logger.log("* Written libraries in ${elapsedSinceLast()}")
 
             logger.log("TOTAL: ${elapsedSinceStart()}")
@@ -76,11 +73,11 @@ class NativeDistributionCommonizer(
         }
     }
 
-    private fun loadModules(): Map<InputTarget, List<NativeModuleForCommonization>> {
+    private fun loadLibraries(): Map<InputTarget, NativeDistributionLibraries> {
         val stdlibPath = repository.resolve(konanCommonLibraryPath(KONAN_STDLIB_NAME))
         val stdlib = loadLibrary(stdlibPath)
 
-        val librariesByTargets = targets.map { target ->
+        return targets.associate { target ->
             val platformLibsPath = repository.resolve(KONAN_DISTRIBUTION_KLIB_DIR)
                 .resolve(KONAN_DISTRIBUTION_PLATFORM_LIBS_DIR)
                 .resolve(target.name)
@@ -91,49 +88,7 @@ class NativeDistributionCommonizer(
                 ?.map { loadLibrary(it) }
                 ?: logger.fatal("no platform libraries found for target $target in $platformLibsPath")
 
-            InputTarget(target.name, target) to platformLibs
+            InputTarget(target.name, target) to NativeDistributionLibraries(stdlib, platformLibs)
-        }.toMap()
-
-        return librariesByTargets.mapValues { (target, libraries) ->
-            val storageManager = LockBasedStorageManager("Target $target")
-
-            val rawStdlibModule = DefaultDeserializedDescriptorFactory.createDescriptorAndNewBuiltIns(
-                library = stdlib,
-                languageVersionSettings = LanguageVersionSettingsImpl.DEFAULT,
-                storageManager = storageManager,
-                packageAccessHandler = null
-            )
-
-            val otherModules = libraries.map { library ->
-                val rawModule = DefaultDeserializedDescriptorFactory.createDescriptorOptionalBuiltIns(
-                    library = library,
-                    languageVersionSettings = LanguageVersionSettingsImpl.DEFAULT,
-                    storageManager = storageManager,
-                    builtIns = rawStdlibModule.builtIns,
-                    packageAccessHandler = null
-                )
-                val data = NativeSensitiveManifestData.readFrom(library)
-                DeserializedModule(rawModule, data, File(library.libraryFile.path))
-            }
-
-            val rawForwardDeclarationsModule =
-                createKotlinNativeForwardDeclarationsModule(
-                    storageManager = storageManager,
-                    builtIns = rawStdlibModule.builtIns
-                )
-
-            val onlyDeserializedModules = listOf(rawStdlibModule) + otherModules.map { it.module }
-            val allModules = onlyDeserializedModules + rawForwardDeclarationsModule
-            onlyDeserializedModules.forEach { it.setDependencies(allModules) }
-
-            val stdlibModule = DeserializedModule(
-                rawStdlibModule,
-                NativeSensitiveManifestData.readFrom(stdlib),
-                File(stdlib.libraryFile.path)
-            )
-            val forwardDeclarationsModule = SyntheticModule(rawForwardDeclarationsModule)
-
-            listOf(stdlibModule) + otherModules + forwardDeclarationsModule
         }
     }
 
@@ -162,25 +117,36 @@ class NativeDistributionCommonizer(
         return library
     }
 
-    private fun commonize(modulesByTargets: Map<InputTarget, List<NativeModuleForCommonization>>): CommonizationPerformed {
+    private fun commonize(librariesByTargets: Map<InputTarget, NativeDistributionLibraries>): CommonizationPerformed {
         val statsCollector = if (withStats) NativeStatsCollector(targets, destination) else null
         statsCollector.use {
-            val parameters = CommonizationParameters(statsCollector).apply {
+            val parameters = Parameters(statsCollector).apply {
-                modulesByTargets.forEach { (target, modules) ->
+                librariesByTargets.forEach { (target, libraries) ->
-                    addTarget(target, modules.map { it.module })
+                    val provider = NativeDistributionModulesProvider(
+                        storageManager = LockBasedStorageManager("Target $target"),
+                        libraries = libraries
+                    )
+                    addTarget(
+                        TargetProvider(
+                            target = target,
+                            builtInsClass = KonanBuiltIns::class.java,
+                            builtInsProvider = provider,
+                            modulesProvider = provider
+                        )
+                    )
                 }
             }
 
             val result = runCommonization(parameters)
             return when (result) {
-                is NothingToCommonize -> logger.fatal("too few targets specified: ${modulesByTargets.keys}")
+                is NothingToCommonize -> logger.fatal("too few targets specified: ${librariesByTargets.keys}")
                 is CommonizationPerformed -> result
             }
         }
     }
 
     private fun saveModules(
-        originalModulesByTargets: Map<InputTarget, List<NativeModuleForCommonization>>,
+        originalLibrariesByTargets: Map<InputTarget, NativeDistributionLibraries>,
         result: CommonizationPerformed
     ) {
         // optimization: stdlib and endorsed libraries effectively remain the same across all Kotlin/Native targets,
@@ -201,13 +167,6 @@ class NativeDistributionCommonizer(
                 }
         }
 
-        val originalModulesManifestData = originalModulesByTargets.mapValues { (_, modules) ->
-            modules.asSequence()
-                .filterIsInstance<DeserializedModule>()
-                .filter { !it.location.endsWith(KONAN_STDLIB_NAME) }
-                .associate { it.module.name to it.data }
-        }
-
         val serializer = KlibMetadataMonolithicSerializer(
             languageVersionSettings = LanguageVersionSettingsImpl.DEFAULT,
             metadataVersion = KlibMetadataVersion.INSTANCE,
@@ -216,16 +175,16 @@ class NativeDistributionCommonizer(
 
         fun serializeTarget(target: Target) {
             val libsDestination: File
-            val newModulesManifestData: Map<Name, NativeSensitiveManifestData>
+            val originalLibraries: NativeDistributionLibraries
 
             when (target) {
                 is InputTarget -> {
                     libsDestination = destination.resolve(KONAN_DISTRIBUTION_PLATFORM_LIBS_DIR).resolve(target.konanTarget!!.name)
-                    newModulesManifestData = originalModulesManifestData.getValue(target)
+                    originalLibraries = originalLibrariesByTargets.getValue(target)
                 }
                 is OutputTarget -> {
                     libsDestination = destination.resolve(KONAN_DISTRIBUTION_COMMON_LIBS_DIR)
-                    newModulesManifestData = originalModulesManifestData.values.first() // just take the first one
+                    originalLibraries = originalLibrariesByTargets.values.first() // just take the first one
                 }
             }
 
@@ -238,8 +197,10 @@ class NativeDistributionCommonizer(
                     continue
 
                 val metadata = serializer.serializeModule(newModule)
-                val manifestData = newModulesManifestData.getValue(newModule.name)
+                val plainName = libraryName.asString().removePrefix("<").removeSuffix(">")
-                val libraryDestination = libsDestination.resolve(libraryName.asString().trimStart('<').trimEnd('>'))
+
+                val manifestData = originalLibraries.index.getValue(plainName).manifestData
+                val libraryDestination = libsDestination.resolve(plainName)
 
                 writeLibrary(metadata, manifestData, libraryDestination)
             }

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/konan/NativeDistributionLibrary.kt

@@ -0,0 +1,26 @@
+/*
+ * 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.descriptors.commonizer.konan
+
+import org.jetbrains.kotlin.library.KotlinLibrary
+
+internal class NativeDistributionLibrary(
+    val library: KotlinLibrary
+) {
+    val manifestData = NativeSensitiveManifestData.readFrom(library)
+}
+
+internal class NativeDistributionLibraries(
+    val stdlib: NativeDistributionLibrary,
+    val platformLibs: List<NativeDistributionLibrary>
+) {
+    constructor(stdlib: KotlinLibrary, platformLibs: List<KotlinLibrary>) : this(
+        NativeDistributionLibrary(stdlib),
+        platformLibs.map(::NativeDistributionLibrary)
+    )
+
+    val index: Map<String, NativeDistributionLibrary> = (platformLibs + stdlib).associateBy { it.manifestData.uniqueName }
+}

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/konan/NativeDistributionModulesProvider.kt

@@ -0,0 +1,68 @@
+/*
+ * 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.descriptors.commonizer.konan
+
+import org.jetbrains.kotlin.builtins.KotlinBuiltIns
+import org.jetbrains.kotlin.config.LanguageVersionSettingsImpl
+import org.jetbrains.kotlin.descriptors.ModuleDescriptor
+import org.jetbrains.kotlin.descriptors.commonizer.BuiltInsProvider
+import org.jetbrains.kotlin.descriptors.commonizer.ModulesProvider
+import org.jetbrains.kotlin.descriptors.commonizer.utils.NativeFactories.DefaultDeserializedDescriptorFactory
+import org.jetbrains.kotlin.descriptors.commonizer.utils.createKotlinNativeForwardDeclarationsModule
+import org.jetbrains.kotlin.konan.library.KONAN_STDLIB_NAME
+import org.jetbrains.kotlin.storage.StorageManager
+
+internal class NativeDistributionModulesProvider(
+    private val storageManager: StorageManager,
+    private val libraries: NativeDistributionLibraries
+) : BuiltInsProvider, ModulesProvider {
+    override fun loadBuiltIns(): KotlinBuiltIns {
+        val stdlib = DefaultDeserializedDescriptorFactory.createDescriptorAndNewBuiltIns(
+            library = libraries.stdlib.library,
+            languageVersionSettings = LanguageVersionSettingsImpl.DEFAULT,
+            storageManager = storageManager,
+            packageAccessHandler = null
+        )
+        stdlib.setDependencies(listOf(stdlib))
+
+        return stdlib.builtIns
+    }
+
+    override fun loadModules(): Collection<ModuleDescriptor> {
+        val builtIns = loadBuiltIns()
+        val stdlib = builtIns.builtInsModule
+
+        val platformModulesMap = libraries.platformLibs.associate { library ->
+            val name = library.manifestData.uniqueName
+            val module = DefaultDeserializedDescriptorFactory.createDescriptorOptionalBuiltIns(
+                library = library.library,
+                languageVersionSettings = LanguageVersionSettingsImpl.DEFAULT,
+                storageManager = storageManager,
+                builtIns = builtIns,
+                packageAccessHandler = null
+            )
+
+            name to module
+        }
+
+        val forwardDeclarations = createKotlinNativeForwardDeclarationsModule(
+            storageManager = storageManager,
+            builtIns = builtIns
+        )
+
+        platformModulesMap.forEach { (name, module) ->
+            val dependencies = libraries.index
+                .getValue(name)
+                .manifestData
+                .dependencies
+                .map { if (it == KONAN_STDLIB_NAME) stdlib else platformModulesMap.getValue(it) }
+
+            module.setDependencies(listOf(module) + dependencies + forwardDeclarations)
+        }
+
+        return platformModulesMap.values
+    }
+}

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/konan/NativeModuleForCommonization.kt

@@ -1,19 +0,0 @@
-/*
- * Copyright 2010-2019 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.descriptors.commonizer.konan
-
-import org.jetbrains.kotlin.descriptors.impl.ModuleDescriptorImpl
-import java.io.File
-
-internal sealed class NativeModuleForCommonization(val module: ModuleDescriptorImpl) {
-    class DeserializedModule(
-        module: ModuleDescriptorImpl,
-        val data: NativeSensitiveManifestData,
-        val location: File
-    ) : NativeModuleForCommonization(module)
-
-    class SyntheticModule(module: ModuleDescriptorImpl) : NativeModuleForCommonization(module)
-}

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/mergedtree/ir/CirModule.kt

@@ -5,10 +5,9 @@
 
 package org.jetbrains.kotlin.descriptors.commonizer.mergedtree.ir
 
-import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.name.Name
 
-data class CirModule(val name: Name, val builtIns: KotlinBuiltIns) : CirDeclaration {
+data class CirModule(val name: Name) : CirDeclaration {
-    constructor(descriptor: ModuleDescriptor) : this(descriptor.name, descriptor.builtIns) // TODO: strong ref
+    constructor(descriptor: ModuleDescriptor) : this(descriptor.name)
 }

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/mergedtree/ir/CirRoot.kt

@@ -5,6 +5,19 @@
 
 package org.jetbrains.kotlin.descriptors.commonizer.mergedtree.ir
 
+import org.jetbrains.kotlin.builtins.konan.KonanBuiltIns
+import org.jetbrains.kotlin.descriptors.commonizer.BuiltInsProvider
+import org.jetbrains.kotlin.descriptors.commonizer.InputTarget
 import org.jetbrains.kotlin.descriptors.commonizer.Target
 
-data class CirRoot(val target: Target) : CirDeclaration
+data class CirRoot(
+    val target: Target,
+    val builtInsClass: String,
+    val builtInsProvider: BuiltInsProvider
+) : CirDeclaration {
+    init {
+        if (target is InputTarget) {
+            check((target.konanTarget != null) == (builtInsClass == KonanBuiltIns::class.java.name))
+        }
+    }
+}

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/mergedtree/ir/nodeBuilders.kt

@@ -6,8 +6,7 @@
 package org.jetbrains.kotlin.descriptors.commonizer.mergedtree.ir
 
 import org.jetbrains.kotlin.descriptors.*
-import org.jetbrains.kotlin.descriptors.commonizer.InputTarget
+import org.jetbrains.kotlin.descriptors.commonizer.TargetProvider
-import org.jetbrains.kotlin.descriptors.commonizer.OutputTarget
 import org.jetbrains.kotlin.descriptors.commonizer.core.*
 import org.jetbrains.kotlin.descriptors.commonizer.mergedtree.ir.CirRootNode.ClassifiersCacheImpl
 import org.jetbrains.kotlin.descriptors.commonizer.utils.CommonizedGroup
@@ -21,12 +20,14 @@ import org.jetbrains.kotlin.storage.StorageManager
 
 internal fun buildRootNode(
     storageManager: StorageManager,
-    targets: List<InputTarget>
+    targetProviders: List<TargetProvider>
-): CirRootNode = CirRootNode(
+): CirRootNode = buildNode(
-    target = targets.map { CirRoot(it) },
+    storageManager = storageManager,
-    common = storageManager.createNullableLazyValue {
+    descriptors = targetProviders,
-        CirRoot(OutputTarget(targets.toSet()))
+    targetDeclarationProducer = { CirRoot(it.target, it.builtInsClass.name, it.builtInsProvider) },
-    }
+    commonValueProducer = { commonize(it, RootCommonizer.default()) },
+    recursionMarker = null,
+    nodeProducer = ::CirRootNode
 )
 
 internal fun buildModuleNode(

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/mergedtree/ir/nodes.kt

@@ -21,7 +21,7 @@ interface CirNodeWithFqName<T : CirDeclaration, R : CirDeclaration> : CirNode<T,
 }
 
 class CirRootNode(
-    override val target: List<CirRoot>,
+    override val target: List<CirRoot?>,
     override val common: NullableLazyValue<CirRoot>
 ) : CirNode<CirRoot, CirRoot> {
     class ClassifiersCacheImpl : CirClassifiersCache {

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/mergedtree/root.kt

@@ -6,7 +6,7 @@
 package org.jetbrains.kotlin.descriptors.commonizer.mergedtree
 
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
-import org.jetbrains.kotlin.descriptors.commonizer.InputTarget
+import org.jetbrains.kotlin.descriptors.commonizer.TargetProvider
 import org.jetbrains.kotlin.descriptors.commonizer.mergedtree.ir.CirRootNode
 import org.jetbrains.kotlin.descriptors.commonizer.mergedtree.ir.buildRootNode
 import org.jetbrains.kotlin.descriptors.commonizer.utils.CommonizedGroupMap
@@ -15,14 +15,14 @@ import org.jetbrains.kotlin.storage.StorageManager
 
 internal fun mergeRoots(
     storageManager: StorageManager,
-    modulesByTargets: List<Pair<InputTarget, Collection<ModuleDescriptor>>>
+    targetProviders: List<TargetProvider>
 ): CirRootNode {
-    val node = buildRootNode(storageManager, modulesByTargets.map { it.first })
+    val node = buildRootNode(storageManager, targetProviders)
 
-    val modulesMap = CommonizedGroupMap<Name, ModuleDescriptor>(modulesByTargets.size)
+    val modulesMap = CommonizedGroupMap<Name, ModuleDescriptor>(targetProviders.size)
 
-    modulesByTargets.forEachIndexed { index, (_, modules) ->
+    targetProviders.forEachIndexed { index, targetProvider ->
-        for (module in modules) {
+        for (module in targetProvider.modulesProvider.loadModules()) {
             modulesMap[module.name][index] = module
         }
     }

native/commonizer/tests/org/jetbrains/kotlin/descriptors/commonizer/AbstractCommonizationFromSourcesTest.kt

@@ -35,9 +35,16 @@ abstract class AbstractCommonizationFromSourcesTest : KtUsefulTestCase() {
             InputTarget("target_$index") to moduleDescriptor
         }.toMap().toCommonizationParameters()
 
-        fun Map<InputTarget, ModuleDescriptor>.toCommonizationParameters() = CommonizationParameters().also {
+        fun Map<InputTarget, ModuleDescriptor>.toCommonizationParameters() = Parameters().also {
             forEach { (target, moduleDescriptor) ->
-                it.addTarget(target, listOf(moduleDescriptor))
+                it.addTarget(
+                    TargetProvider(
+                        target = target,
+                        builtInsClass = moduleDescriptor.builtIns::class.java,
+                        builtInsProvider = BuiltInsProvider.wrap(moduleDescriptor.builtIns),
+                        modulesProvider = ModulesProvider.wrap(moduleDescriptor)
+                    )
+                )
             }
         }
     }

native/commonizer/tests/org/jetbrains/kotlin/descriptors/commonizer/CommonizerFacadeTest.kt

@@ -55,19 +55,6 @@ class CommonizerFacadeTest {
         }
     }
 
-    @Test
-    fun mismatchedModules() {
-        val modules = listOf(
-            mockEmptyModule("<foo>"),
-            mockEmptyModule("<foo>"),
-            mockEmptyModule("<bar>")
-        )
-
-        val result = runCommonization(modules.eachModuleAsTarget())
-
-        assertEquals(NothingToCommonize, result)
-    }
-
     private fun assertSingleModuleForTarget(
         @Suppress("SameParameterValue") expectedModuleName: String,
         modules: Collection<ModuleDescriptor>

native/commonizer/tests/org/jetbrains/kotlin/descriptors/commonizer/core/DefaultModuleCommonizerTest.kt

@@ -1,79 +0,0 @@
-/*
- * Copyright 2010-2019 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.descriptors.commonizer.core
-
-import org.jetbrains.kotlin.builtins.DefaultBuiltIns
-import org.jetbrains.kotlin.builtins.KotlinBuiltIns
-import org.jetbrains.kotlin.builtins.jvm.JvmBuiltIns
-import org.jetbrains.kotlin.builtins.konan.KonanBuiltIns
-import org.jetbrains.kotlin.descriptors.commonizer.mergedtree.ir.CirModule
-import org.jetbrains.kotlin.name.Name
-import org.jetbrains.kotlin.storage.LockBasedStorageManager
-import org.junit.Test
-
-class DefaultModuleCommonizerTest : AbstractCommonizerTest<CirModule, CirModule>() {
-
-    @Test
-    fun allAreNative() = doTestSuccess(
-        KONAN_BUILT_INS.toMock(),
-        KONAN_BUILT_INS.toMock(),
-        KONAN_BUILT_INS.toMock(),
-        KONAN_BUILT_INS.toMock()
-    )
-
-    @Test
-    fun jvmAndNative1() = doTestSuccess(
-        DEFAULT_BUILT_INS.toMock(),
-        JVM_BUILT_INS.toMock(),
-        KONAN_BUILT_INS.toMock(),
-        JVM_BUILT_INS.toMock()
-    )
-
-    @Test
-    fun jvmAndNative2() = doTestSuccess(
-        DEFAULT_BUILT_INS.toMock(),
-        KONAN_BUILT_INS.toMock(),
-        JVM_BUILT_INS.toMock(),
-        KONAN_BUILT_INS.toMock()
-    )
-
-    @Test
-    fun noNative1() = doTestSuccess(
-        DEFAULT_BUILT_INS.toMock(),
-        JVM_BUILT_INS.toMock(),
-        JVM_BUILT_INS.toMock(),
-        JVM_BUILT_INS.toMock()
-    )
-
-    @Test
-    fun noNative2() = doTestSuccess(
-        DEFAULT_BUILT_INS.toMock(),
-        DEFAULT_BUILT_INS.toMock(),
-        DEFAULT_BUILT_INS.toMock(),
-        DEFAULT_BUILT_INS.toMock()
-    )
-
-    @Test
-    fun noNative3() = doTestSuccess(
-        DEFAULT_BUILT_INS.toMock(),
-        JVM_BUILT_INS.toMock(),
-        DEFAULT_BUILT_INS.toMock(),
-        JVM_BUILT_INS.toMock()
-    )
-
-    override fun createCommonizer() = ModuleCommonizer.default()
-
-    override fun isEqual(a: CirModule?, b: CirModule?) =
-        (a === b) || (a != null && b != null && a.name == b.name && a.builtIns::class.java.name == b.builtIns::class.java.name)
-
-    private companion object {
-        inline val KONAN_BUILT_INS get() = KonanBuiltIns(LockBasedStorageManager.NO_LOCKS)
-        inline val JVM_BUILT_INS get() = JvmBuiltIns(LockBasedStorageManager.NO_LOCKS, JvmBuiltIns.Kind.FROM_CLASS_LOADER)
-        inline val DEFAULT_BUILT_INS get() = DefaultBuiltIns.Instance
-
-        fun KotlinBuiltIns.toMock() = CirModule(Name.identifier("fakeModule"), this)
-    }
-}

native/commonizer/tests/org/jetbrains/kotlin/descriptors/commonizer/core/DefaultRootCommonizerTest.kt

@@ -0,0 +1,172 @@
+/*
+ * 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.descriptors.commonizer.core
+
+import org.jetbrains.kotlin.builtins.DefaultBuiltIns
+import org.jetbrains.kotlin.builtins.KotlinBuiltIns
+import org.jetbrains.kotlin.builtins.jvm.JvmBuiltIns
+import org.jetbrains.kotlin.builtins.konan.KonanBuiltIns
+import org.jetbrains.kotlin.descriptors.commonizer.BuiltInsProvider
+import org.jetbrains.kotlin.descriptors.commonizer.InputTarget
+import org.jetbrains.kotlin.descriptors.commonizer.OutputTarget
+import org.jetbrains.kotlin.descriptors.commonizer.Target
+import org.jetbrains.kotlin.descriptors.commonizer.mergedtree.ir.CirRoot
+import org.jetbrains.kotlin.konan.target.KonanTarget
+import org.jetbrains.kotlin.storage.LockBasedStorageManager
+import org.junit.Test
+
+class DefaultRootCommonizerTest : AbstractCommonizerTest<CirRoot, CirRoot>() {
+
+    @Test
+    fun allAreNative() = doTestSuccess(
+        KONAN_BUILT_INS.toMock(
+            OutputTarget(
+                setOf(
+                    InputTarget("ios_x64", KonanTarget.IOS_X64),
+                    InputTarget("ios_arm64", KonanTarget.IOS_ARM64),
+                    InputTarget("ios_arm32", KonanTarget.IOS_ARM32)
+                )
+            )
+        ),
+        KONAN_BUILT_INS.toMock(InputTarget("ios_x64", KonanTarget.IOS_X64)),
+        KONAN_BUILT_INS.toMock(InputTarget("ios_arm64", KonanTarget.IOS_ARM64)),
+        KONAN_BUILT_INS.toMock(InputTarget("ios_arm32", KonanTarget.IOS_ARM32))
+    )
+
+    @Test
+    fun jvmAndNative1() = doTestSuccess(
+        DEFAULT_BUILT_INS.toMock(
+            OutputTarget(
+                setOf(
+                    InputTarget("jvm1"),
+                    InputTarget("ios_x64", KonanTarget.IOS_X64),
+                    InputTarget("jvm2")
+                )
+            )
+        ),
+        JVM_BUILT_INS.toMock(InputTarget("jvm1")),
+        KONAN_BUILT_INS.toMock(InputTarget("ios_x64", KonanTarget.IOS_X64)),
+        JVM_BUILT_INS.toMock(InputTarget("jvm2"))
+    )
+
+    @Test
+    fun jvmAndNative2() = doTestSuccess(
+        DEFAULT_BUILT_INS.toMock(
+            OutputTarget(
+                setOf(
+                    InputTarget("ios_x64", KonanTarget.IOS_X64),
+                    InputTarget("jvm"),
+                    InputTarget("ios_arm64", KonanTarget.IOS_ARM64)
+                )
+            )
+        ),
+        KONAN_BUILT_INS.toMock(InputTarget("ios_x64", KonanTarget.IOS_X64)),
+        JVM_BUILT_INS.toMock(InputTarget("jvm")),
+        KONAN_BUILT_INS.toMock(InputTarget("ios_arm64", KonanTarget.IOS_ARM64))
+    )
+
+    @Test
+    fun noNative1() = doTestSuccess(
+        DEFAULT_BUILT_INS.toMock(
+            OutputTarget(
+                setOf(
+                    InputTarget("default1"),
+                    InputTarget("default2"),
+                    InputTarget("default3")
+                )
+            )
+        ),
+        DEFAULT_BUILT_INS.toMock(InputTarget("default1")),
+        DEFAULT_BUILT_INS.toMock(InputTarget("default2")),
+        DEFAULT_BUILT_INS.toMock(InputTarget("default3"))
+    )
+
+    @Test
+    fun noNative2() = doTestSuccess(
+        DEFAULT_BUILT_INS.toMock(
+            OutputTarget(
+                setOf(
+                    InputTarget("jvm1"),
+                    InputTarget("default"),
+                    InputTarget("jvm2")
+                )
+            )
+        ),
+        JVM_BUILT_INS.toMock(InputTarget("jvm1")),
+        DEFAULT_BUILT_INS.toMock(InputTarget("default")),
+        JVM_BUILT_INS.toMock(InputTarget("jvm2"))
+    )
+
+    @Test
+    fun noNative3() = doTestSuccess(
+        DEFAULT_BUILT_INS.toMock(
+            OutputTarget(
+                setOf(
+                    InputTarget("jvm1"),
+                    InputTarget("jvm2"),
+                    InputTarget("jvm3")
+                )
+            )
+        ),
+        JVM_BUILT_INS.toMock(InputTarget("jvm1")),
+        JVM_BUILT_INS.toMock(InputTarget("jvm2")),
+        JVM_BUILT_INS.toMock(InputTarget("jvm3"))
+    )
+
+    @Test(expected = IllegalStateException::class)
+    fun misconfiguration1() = doTestSuccess(
+        KONAN_BUILT_INS.toMock(
+            OutputTarget(
+                setOf(
+                    InputTarget("ios_x64", KonanTarget.IOS_X64),
+                    InputTarget("ios_arm64", KonanTarget.IOS_ARM64),
+                    InputTarget("ios_arm32", KonanTarget.IOS_ARM32)
+                )
+            )
+        ),
+        KONAN_BUILT_INS.toMock(InputTarget("ios_x64")),
+        KONAN_BUILT_INS.toMock(InputTarget("ios_arm64", KonanTarget.IOS_ARM64)),
+        KONAN_BUILT_INS.toMock(InputTarget("ios_arm32", KonanTarget.IOS_ARM32))
+    )
+
+    @Test(expected = IllegalStateException::class)
+    fun misconfiguration2() = doTestSuccess(
+        DEFAULT_BUILT_INS.toMock(
+            OutputTarget(
+                setOf(
+                    InputTarget("jvm1"),
+                    InputTarget("jvm2"),
+                    InputTarget("jvm3")
+                )
+            )
+        ),
+        JVM_BUILT_INS.toMock(InputTarget("jvm1", KonanTarget.IOS_X64)),
+        JVM_BUILT_INS.toMock(InputTarget("jvm2")),
+        JVM_BUILT_INS.toMock(InputTarget("jvm3"))
+    )
+
+    override fun createCommonizer() = RootCommonizer.default()
+
+    override fun isEqual(a: CirRoot?, b: CirRoot?) =
+        (a === b)
+                || (a != null && b != null
+                && a.target == b.target
+                && a.builtInsClass == b.builtInsClass
+                && a.builtInsClass == a.builtInsProvider.loadBuiltIns()::class.java.name
+                && a.builtInsProvider.loadBuiltIns()::class.java == b.builtInsProvider.loadBuiltIns()::class.java)
+
+    private companion object {
+        inline val KONAN_BUILT_INS get() = KonanBuiltIns(LockBasedStorageManager.NO_LOCKS)
+        inline val JVM_BUILT_INS get() = JvmBuiltIns(LockBasedStorageManager.NO_LOCKS, JvmBuiltIns.Kind.FROM_CLASS_LOADER)
+        inline val DEFAULT_BUILT_INS get() = DefaultBuiltIns.Instance
+
+        fun KotlinBuiltIns.toMock(target: Target) = CirRoot(
+            target,
+            this::class.java.name,
+            BuiltInsProvider.wrap(this)
+        )
+    }
+}

native/commonizer/tests/org/jetbrains/kotlin/descriptors/commonizer/utils/assertions.kt

@@ -7,7 +7,7 @@ package org.jetbrains.kotlin.descriptors.commonizer.utils
 
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.commonizer.CommonizationPerformed
-import org.jetbrains.kotlin.descriptors.commonizer.CommonizationResult
+import org.jetbrains.kotlin.descriptors.commonizer.Result
 import org.jetbrains.kotlin.test.util.DescriptorValidator.*
 import org.jetbrains.kotlin.types.ErrorUtils
 import java.io.File
@@ -22,7 +22,7 @@ fun assertIsDirectory(file: File) {
 }
 
 @ExperimentalContracts
-fun assertCommonizationPerformed(result: CommonizationResult) {
+fun assertCommonizationPerformed(result: Result) {
     contract {
         returns() implies (result is CommonizationPerformed)
     }