JS IC: IC lowerings prototype

compiler/cli/cli-js/src/org/jetbrains/kotlin/cli/js/K2JsIrCompiler.kt

@@ -38,6 +38,8 @@ import org.jetbrains.kotlin.incremental.js.IncrementalDataProvider
 import org.jetbrains.kotlin.incremental.js.IncrementalNextRoundChecker
 import org.jetbrains.kotlin.incremental.js.IncrementalResultsConsumer
 import org.jetbrains.kotlin.ir.backend.js.*
+import org.jetbrains.kotlin.ir.backend.js.ic.buildCache
+import org.jetbrains.kotlin.ir.backend.js.ic.checkCaches
 import org.jetbrains.kotlin.ir.declarations.impl.IrFactoryImpl
 import org.jetbrains.kotlin.ir.declarations.persistent.PersistentIrFactory
 import org.jetbrains.kotlin.js.config.*
@@ -179,6 +181,43 @@ class K2JsIrCompiler : CLICompiler<K2JSCompilerArguments>() {
         // TODO: Handle non-empty main call arguments
         val mainCallArguments = if (K2JsArgumentConstants.NO_CALL == arguments.main) null else emptyList<String>()
 
+        val icCaches = configureLibraries(arguments.cacheDirectories)
+
+        if (arguments.irBuildCache) {
+            messageCollector.report(INFO, "")
+            messageCollector.report(INFO, "Building cache:")
+            messageCollector.report(INFO, "to: ${outputFilePath}")
+            messageCollector.report(INFO, arguments.cacheDirectories ?: "")
+            messageCollector.report(INFO, resolvedLibraries.getFullList().map { it.libraryName }.toString())
+
+            val includes = arguments.includes!!
+
+            // TODO: deduplicate
+            val mainModule = run {
+                if (sourcesFiles.isNotEmpty()) {
+                    messageCollector.report(ERROR, "Source files are not supported when -Xinclude is present")
+                }
+                val allLibraries = resolvedLibraries.getFullList()
+                val mainLib = allLibraries.find { it.libraryFile.absolutePath == File(includes).absolutePath }!!
+                MainModule.Klib(mainLib)
+            }
+
+            val start = System.currentTimeMillis()
+            buildCache(
+                cachePath = outputFilePath,
+                project = projectJs,
+                mainModule = mainModule,
+                analyzer = AnalyzerWithCompilerReport(config.configuration),
+                configuration = config.configuration,
+                allDependencies = resolvedLibraries,
+                friendDependencies = friendDependencies,
+                icCache = checkCaches(resolvedLibraries, icCaches, skipLib = mainModule.lib.libraryFile.absolutePath)
+            )
+
+            messageCollector.report(INFO, "IC cache building duration: ${System.currentTimeMillis() - start}ms")
+            return OK
+        }
+
         if (arguments.irProduceKlibDir || arguments.irProduceKlibFile) {
             if (arguments.irProduceKlibFile) {
                 require(outputFile.extension == KLIB_FILE_EXTENSION) { "Please set up .klib file as output" }
@@ -199,6 +238,9 @@ class K2JsIrCompiler : CLICompiler<K2JSCompilerArguments>() {
         }
 
         if (arguments.irProduceJs) {
+            messageCollector.report(INFO,"Produce executable: $outputFilePath")
+            messageCollector.report(INFO, arguments.cacheDirectories ?: "")
+
             val phaseConfig = createPhaseConfig(jsPhases, arguments, messageCollector)
 
             val includes = arguments.includes
@@ -243,6 +285,8 @@ class K2JsIrCompiler : CLICompiler<K2JSCompilerArguments>() {
                 return OK
             }
 
+            val start = System.currentTimeMillis()
+
             val compiledModule = compile(
                 projectJs,
                 mainModule,
@@ -270,8 +314,13 @@ class K2JsIrCompiler : CLICompiler<K2JSCompilerArguments>() {
                     arguments.irSafeExternalBooleanDiagnostic,
                     messageCollector
                 ),
+                lowerPerModule = icCaches.isNotEmpty(),
+                useStdlibCache = icCaches.isNotEmpty(),
+                icCache = if (icCaches.isNotEmpty()) checkCaches(resolvedLibraries, icCaches, skipLib = (mainModule as MainModule.Klib).lib.libraryFile.absolutePath).data else emptyMap(),
             )
 
+            messageCollector.report(INFO, "Executable production duration: ${System.currentTimeMillis() - start}ms")
+
             val outputs = if (arguments.irDce && !arguments.irDceDriven) compiledModule.outputsAfterDce!! else compiledModule.outputs!!
             outputFile.write(outputs)
             outputs.dependencies.forEach { (name, content) ->

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/Dce.kt

@@ -136,7 +136,9 @@ private fun processUselessDeclarations(
                     // Remove annotations for `findAssociatedObject` feature, which reference objects eliminated by the DCE.
                     // Otherwise `JsClassGenerator.generateAssociatedKeyProperties` will try to reference the object factory (which is removed).
                     // That will result in an error from the Namer. It cannot generate a name for an absent declaration.
-                    declaration.annotations = declaration.annotations.filter { it.shouldKeepAnnotation() }
+                    if (declaration.annotations.any { !it.shouldKeepAnnotation() }) {
+                        declaration.annotations = declaration.annotations.filter { it.shouldKeepAnnotation() }
+                    }
                 }
 
                 // TODO bring back the primary constructor fix

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsIrBackendContext.kt

@@ -60,6 +60,7 @@ class JsIrBackendContext(
     val baseClassIntoMetadata: Boolean = false,
     val safeExternalBoolean: Boolean = false,
     val safeExternalBooleanDiagnostic: RuntimeDiagnostic? = null,
+    override val mapping: JsMapping = JsMapping(symbolTable.irFactory)
 ) : JsCommonBackendContext {
     val fileToInitializationFuns: MutableMap<IrFile, IrSimpleFunction?> = mutableMapOf()
     val fileToInitializerPureness: MutableMap<IrFile, Boolean> = mutableMapOf()
@@ -137,8 +138,6 @@ class JsIrBackendContext(
     val testRoots: Map<IrModuleFragment, IrSimpleFunction>
         get() = testContainerFuns
 
-    override val mapping = JsMapping(irFactory)
-
     override val inlineClassesUtils = JsInlineClassesUtils(this)
 
     val innerClassesSupport = JsInnerClassesSupport(mapping, irFactory)

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/WholeWorldStageController.kt

@@ -7,7 +7,9 @@ package org.jetbrains.kotlin.ir.backend.js
 
 import org.jetbrains.kotlin.descriptors.DescriptorVisibilities
 import org.jetbrains.kotlin.ir.declarations.IrClass
+import org.jetbrains.kotlin.ir.declarations.IrDeclaration
 import org.jetbrains.kotlin.ir.declarations.StageController
+import org.jetbrains.kotlin.ir.util.IdSignature
 
 // Only allows to apply a lowering to the whole world and save the result
 class WholeWorldStageController : StageController() {
@@ -15,8 +17,30 @@ class WholeWorldStageController : StageController() {
 
     // TODO assert lowered
 
+    override var currentDeclaration: IrDeclaration? = null
+    private var index: Int = 0
+
     var declarationListsRestricted: Boolean = false
 
+    override fun <T> restrictTo(declaration: IrDeclaration, fn: () -> T): T {
+        val previousCurrentDeclaration = currentDeclaration
+        val previousIndex = index
+
+        currentDeclaration = declaration
+        index = 0
+
+        return try {
+            fn()
+        } finally {
+            currentDeclaration = previousCurrentDeclaration
+            index = previousIndex
+        }
+    }
+
+    override fun createSignature(parentSignature: IdSignature): IdSignature {
+        return IdSignature.LoweredDeclarationSignature(parentSignature, currentStage, index++)
+    }
+
     override fun <T> withStage(stage: Int, fn: () -> T): T {
         val oldStage = currentStage
         currentStage = stage

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/compiler.kt

@@ -11,6 +11,8 @@ import org.jetbrains.kotlin.backend.common.lower
 import org.jetbrains.kotlin.backend.common.phaser.PhaseConfig
 import org.jetbrains.kotlin.backend.common.phaser.invokeToplevel
 import org.jetbrains.kotlin.config.CompilerConfiguration
+import org.jetbrains.kotlin.ir.backend.js.ic.SerializedIcData
+import org.jetbrains.kotlin.ir.backend.js.ic.icCompile
 import org.jetbrains.kotlin.ir.backend.js.lower.generateTests
 import org.jetbrains.kotlin.ir.backend.js.lower.moveBodilessDeclarationsToSeparatePlace
 import org.jetbrains.kotlin.ir.backend.js.transformers.irToJs.IrModuleToJsTransformer
@@ -19,8 +21,7 @@ import org.jetbrains.kotlin.ir.declarations.IrFactory
 import org.jetbrains.kotlin.ir.declarations.IrModuleFragment
 import org.jetbrains.kotlin.ir.declarations.StageController
 import org.jetbrains.kotlin.ir.declarations.persistent.PersistentIrFactory
-import org.jetbrains.kotlin.ir.util.ExternalDependenciesGenerator
+import org.jetbrains.kotlin.ir.util.*
-import org.jetbrains.kotlin.ir.util.noUnboundLeft
 import org.jetbrains.kotlin.js.config.RuntimeDiagnostic
 import org.jetbrains.kotlin.name.FqName
 
@@ -61,7 +62,32 @@ fun compile(
     lowerPerModule: Boolean = false,
     safeExternalBoolean: Boolean = false,
     safeExternalBooleanDiagnostic: RuntimeDiagnostic? = null,
+    useStdlibCache: Boolean = false,
+    icCache: Map<String, SerializedIcData> = emptyMap(),
 ): CompilerResult {
+
+    if (lowerPerModule) {
+        return icCompile(
+            project,
+            mainModule,
+            analyzer,
+            configuration,
+            allDependencies,
+            friendDependencies,
+            mainArguments,
+            exportedDeclarations,
+            generateFullJs,
+            generateDceJs,
+            dceRuntimeDiagnostic,
+            es6mode,
+            multiModule,
+            relativeRequirePath,
+            propertyLazyInitialization,
+            useStdlibCache,
+            icCache,
+        )
+    }
+
     val (moduleFragment: IrModuleFragment, dependencyModules, irBuiltIns, symbolTable, deserializer, moduleToName) =
         loadIr(project, mainModule, analyzer, configuration, dependencies, friendDependencies, irFactory, verifySignatures)
 
@@ -125,6 +151,7 @@ fun compile(
         )
         return transformer.generateModule(allModules)
     } else {
+        // TODO is this reachable when lowerPerModule == true?
         if (lowerPerModule) {
             val controller = WholeWorldStageController()
             check(irFactory is PersistentIrFactory)
@@ -132,6 +159,7 @@ fun compile(
             allModules.forEach {
                 lowerPreservingIcData(it, context, controller)
             }
+            irFactory.stageController = object : StageController(irFactory.stageController.currentStage) {}
         } else {
             jsPhases.invokeToplevel(phaseConfig, context, allModules)
         }

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/ic/fileUtil.kt

@@ -0,0 +1,153 @@
+/*
+ * 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.ir.backend.js.ic
+
+import com.intellij.openapi.project.Project
+import org.jetbrains.kotlin.analyzer.AbstractAnalyzerWithCompilerReport
+import org.jetbrains.kotlin.config.CompilerConfiguration
+import org.jetbrains.kotlin.ir.backend.js.MainModule
+import org.jetbrains.kotlin.ir.backend.js.toByteArray
+import org.jetbrains.kotlin.library.KotlinLibrary
+import org.jetbrains.kotlin.library.impl.javaFile
+import org.jetbrains.kotlin.library.resolver.KotlinLibraryResolveResult
+import org.jetbrains.kotlin.library.resolver.TopologicalLibraryOrder
+import org.jetbrains.kotlin.name.FqName
+import java.io.File
+import java.io.PrintWriter
+import java.security.MessageDigest
+import kotlin.random.Random
+import kotlin.random.nextULong
+
+// TODO: Proper version of the compiler (should take changes to lowerings into account)
+private val compilerVersion = Random.nextULong()
+
+// TODO more parameters for lowerings
+fun buildCache(
+    cachePath: String,
+    project: Project,
+    mainModule: MainModule.Klib,
+    analyzer: AbstractAnalyzerWithCompilerReport,
+    configuration: CompilerConfiguration,
+    allDependencies: KotlinLibraryResolveResult,
+    friendDependencies: List<KotlinLibrary>,
+    exportedDeclarations: Set<FqName> = emptySet(),
+    forceClean: Boolean = false,
+    icCache: IcCacheInfo = IcCacheInfo.EMPTY,
+) {
+    val dependencyHashes = allDependencies.getFullList(TopologicalLibraryOrder).mapNotNull {
+        val path = it.libraryFile.absolutePath
+        icCache.md5[path]
+    } + compilerVersion
+
+    val md5 = mainModule.lib.libraryFile.javaFile().md5(dependencyHashes)
+
+    if (!forceClean) {
+        val oldCacheInfo = CacheInfo.load(cachePath)
+        if (oldCacheInfo != null && md5 == oldCacheInfo.md5) return
+    }
+
+    val icDir = File(cachePath)
+    icDir.deleteRecursively()
+    icDir.mkdirs()
+
+    val icData = prepareSingleLibraryIcCache(project, analyzer, configuration, mainModule.lib, allDependencies, friendDependencies, exportedDeclarations, icCache.data)
+
+    icData.writeTo(File(cachePath))
+
+    CacheInfo(cachePath, mainModule.lib.libraryFile.absolutePath, md5).save()
+}
+
+private fun File.md5(additional: Iterable<ULong> = emptyList()): ULong {
+    val md5 = MessageDigest.getInstance("MD5")
+
+    for (ul in additional) {
+        md5.update(ul.toLong().toByteArray())
+    }
+
+    fun File.process(prefix: String = "") {
+        if (isDirectory) {
+            this.listFiles()!!.sortedBy { it.name }.forEach {
+                md5.update((prefix + it.name).toByteArray())
+                it.process(prefix + it.name + "/")
+            }
+        } else {
+            md5.update(readBytes())
+        }
+    }
+
+    this.process()
+
+    val d = md5.digest()
+
+    return ((d[0].toULong() and 0xFFUL)
+            or ((d[1].toULong() and 0xFFUL) shl 8)
+            or ((d[2].toULong() and 0xFFUL) shl 16)
+            or ((d[3].toULong() and 0xFFUL) shl 24)
+            or ((d[4].toULong() and 0xFFUL) shl 32)
+            or ((d[5].toULong() and 0xFFUL) shl 40)
+            or ((d[6].toULong() and 0xFFUL) shl 48)
+            or ((d[7].toULong() and 0xFFUL) shl 56)
+            )
+}
+
+fun checkCaches(
+    allDependencies: KotlinLibraryResolveResult,
+    cachePaths: List<String>,
+    skipLib: String? = null,
+): IcCacheInfo {
+    val allLibs = allDependencies.getFullList().map { it.libraryFile.absolutePath }.toSet() - skipLib
+
+    val caches = cachePaths.map { CacheInfo.load(it) ?: error("Cannot load IC cache from ${it}") }
+
+    val missedLibs = allLibs - caches.map { it.libPath }
+    if (!missedLibs.isEmpty()) {
+        error("Missing caches for libraries: ${missedLibs}")
+    }
+
+    val result = mutableMapOf<String, SerializedIcData>()
+    val md5 = mutableMapOf<String, ULong>()
+
+    for (c in caches) {
+        if (c.libPath !in allLibs) error("Missing library: ${c.libPath}")
+
+        result[c.libPath] = File(c.path).readIcData()
+        md5[c.libPath] = c.md5
+    }
+
+    return IcCacheInfo(result, md5)
+}
+
+// TODO md5 hash
+data class CacheInfo(val path: String, val libPath: String, val md5: ULong) {
+    fun save() {
+        PrintWriter(File(File(path), "info")).use {
+            it.println(libPath)
+            it.println(md5.toString(16))
+        }
+    }
+
+    companion object {
+        fun load(path: String): CacheInfo? {
+            val info = File(File(path), "info")
+
+            if (!info.exists()) return null
+
+            val (libPath, md5) = info.readLines()
+
+            return CacheInfo(path, libPath, md5.toULong(16))
+        }
+    }
+}
+
+
+class IcCacheInfo(
+    val data: Map<String, SerializedIcData>,
+    val md5: Map<String, ULong>,
+) {
+    companion object {
+        val EMPTY = IcCacheInfo(emptyMap(), emptyMap())
+    }
+}

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/ic/ic.kt

@@ -0,0 +1,277 @@
+/*
+ * 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.ir.backend.js.ic
+
+import com.intellij.openapi.project.Project
+import org.jetbrains.kotlin.analyzer.AbstractAnalyzerWithCompilerReport
+import org.jetbrains.kotlin.backend.common.lower
+import org.jetbrains.kotlin.config.CompilerConfiguration
+import org.jetbrains.kotlin.ir.backend.js.*
+import org.jetbrains.kotlin.ir.backend.js.lower.generateTests
+import org.jetbrains.kotlin.ir.backend.js.lower.moveBodilessDeclarationsToSeparatePlace
+import org.jetbrains.kotlin.ir.backend.js.lower.serialization.ir.JsIrLinker
+import org.jetbrains.kotlin.ir.backend.js.transformers.irToJs.IrModuleToJsTransformer
+import org.jetbrains.kotlin.ir.declarations.*
+import org.jetbrains.kotlin.ir.declarations.persistent.PersistentIrFactory
+import org.jetbrains.kotlin.ir.util.*
+import org.jetbrains.kotlin.js.config.RuntimeDiagnostic
+import org.jetbrains.kotlin.library.KotlinLibrary
+import org.jetbrains.kotlin.library.resolver.KotlinLibraryResolveResult
+import org.jetbrains.kotlin.library.resolver.KotlinResolvedLibrary
+import org.jetbrains.kotlin.name.FqName
+import java.io.PrintWriter
+
+fun prepareSingleLibraryIcCache(
+    project: Project,
+    analyzer: AbstractAnalyzerWithCompilerReport,
+    configuration: CompilerConfiguration,
+    library: KotlinLibrary,
+    dependencies: KotlinLibraryResolveResult,
+    friendDependencies: List<KotlinLibrary> = emptyList(),
+    exportedDeclarations: Set<FqName> = emptySet(),
+    icCache: Map<String, SerializedIcData> = emptyMap(),
+): SerializedIcData {
+    val irFactory = PersistentIrFactory()
+    val controller = WholeWorldStageController()
+    irFactory.stageController = controller
+
+    val (context, deserializer, allModules) = prepareIr(
+        project,
+        MainModule.Klib(library),
+        analyzer,
+        configuration,
+        dependencies,
+        friendDependencies,
+        exportedDeclarations,
+        null,
+        false,
+        false,
+        irFactory,
+        useGlobalSignatures = true,
+        useStdlibCache = true,
+        icCache = icCache
+    )
+
+    val moduleFragment = allModules.last()
+
+    moveBodilessDeclarationsToSeparatePlace(context, moduleFragment)
+
+//    generateTests(context, moduleFragment)
+
+    lowerPreservingIcData(moduleFragment, context, controller)
+
+    return IcSerializer(
+        context.irBuiltIns,
+        context.mapping,
+        irFactory,
+        deserializer,
+        moduleFragment
+    ).serializeDeclarations(irFactory.allDeclarations)
+}
+
+private fun KotlinResolvedLibrary.allDependencies(): List<KotlinResolvedLibrary> {
+    val visited = mutableSetOf<KotlinResolvedLibrary>()
+
+    val result = mutableListOf<KotlinResolvedLibrary>()
+
+    fun KotlinResolvedLibrary.dfs() {
+        visited += this
+
+        resolvedDependencies.forEach {
+            if (it !in visited) {
+                it.dfs()
+                result += it
+            }
+        }
+    }
+
+    dfs()
+
+    return result
+}
+
+private fun dumpIr(module: IrModuleFragment, fileName: String) {
+    val dumpOptions = KotlinLikeDumpOptions(printElseAsTrue = true)
+
+    var actual = ""
+
+    for (file in module.files) {
+        actual += file.path + "\n"
+        actual += run {
+            var r = ""
+
+            file.declarations.map { it.dumpKotlinLike(dumpOptions) }.sorted().forEach { r += it }
+
+            r
+        }
+        actual += "\n"
+    }
+    PrintWriter("/home/ab/vcs/kotlin/$fileName.txt").use {
+        it.print(actual)
+    }
+}
+
+fun icCompile(
+    project: Project,
+    mainModule: MainModule,
+    analyzer: AbstractAnalyzerWithCompilerReport,
+    configuration: CompilerConfiguration,
+    allDependencies: KotlinLibraryResolveResult,
+    friendDependencies: List<KotlinLibrary>,
+    mainArguments: List<String>?,
+    exportedDeclarations: Set<FqName> = emptySet(),
+    generateFullJs: Boolean = true,
+    generateDceJs: Boolean = false,
+    dceRuntimeDiagnostic: RuntimeDiagnostic? = null,
+    es6mode: Boolean = false,
+    multiModule: Boolean = false,
+    relativeRequirePath: Boolean = false,
+    propertyLazyInitialization: Boolean,
+    useStdlibCache: Boolean,
+    icCache: Map<String, SerializedIcData> = emptyMap()
+): CompilerResult {
+
+    val irFactory = PersistentIrFactory()
+    val controller = WholeWorldStageController()
+    irFactory.stageController = controller
+
+    val (context, _, allModules, moduleToName, loweredIrLoaded) = prepareIr(
+        project,
+        mainModule,
+        analyzer,
+        configuration,
+        allDependencies,
+        friendDependencies,
+        exportedDeclarations,
+        dceRuntimeDiagnostic,
+        es6mode,
+        propertyLazyInitialization,
+        irFactory,
+        useStdlibCache,
+        useStdlibCache,
+        icCache,
+    )
+
+    val modulesToLower = allModules.filter { it !in loweredIrLoaded }
+
+
+
+    if (!modulesToLower.isEmpty()) {
+        // This won't work incrementally
+        modulesToLower.forEach { module ->
+            moveBodilessDeclarationsToSeparatePlace(context, module)
+        }
+
+        generateTests(context, modulesToLower.last())
+
+        modulesToLower.forEach {
+            lowerPreservingIcData(it, context, controller)
+        }
+    }
+
+//    dumpIr(allModules.first(), "simple-dump${if (useStdlibCache) "-actual" else ""}")
+
+    val transformer = IrModuleToJsTransformer(
+        context,
+        mainArguments,
+        fullJs = generateFullJs,
+        dceJs = generateDceJs,
+        multiModule = multiModule,
+        relativeRequirePath = relativeRequirePath,
+        moduleToName = moduleToName,
+    )
+
+    irFactory.stageController = object : StageController(999) {}
+
+    return transformer.generateModule(allModules)
+}
+
+fun lowerPreservingIcData(module: IrModuleFragment, context: JsIrBackendContext, controller: WholeWorldStageController) {
+    // Lower all the things
+    controller.currentStage = 0
+
+    pirLowerings.forEachIndexed { i, lowering ->
+        controller.currentStage = i + 1
+        when (lowering) {
+            is DeclarationLowering ->
+                lowering.declarationTransformer(context).lower(module)
+            is BodyLowering ->
+                lowering.bodyLowering(context).lower(module)
+            else -> TODO("what about other lowerings?")
+        }
+    }
+
+    controller.currentStage = pirLowerings.size + 1
+}
+
+private fun prepareIr(
+    project: Project,
+    mainModule: MainModule,
+    analyzer: AbstractAnalyzerWithCompilerReport,
+    configuration: CompilerConfiguration,
+    allDependencies: KotlinLibraryResolveResult,
+    friendDependencies: List<KotlinLibrary>,
+    exportedDeclarations: Set<FqName> = emptySet(),
+    dceRuntimeDiagnostic: RuntimeDiagnostic? = null,
+    es6mode: Boolean = false,
+    propertyLazyInitialization: Boolean,
+    irFactory: PersistentIrFactory,
+    useGlobalSignatures: Boolean,
+    useStdlibCache: Boolean,
+    icCache: Map<String, SerializedIcData>,
+): PreparedIr {
+    val cacheProvider: LoweringsCacheProvider? = when {
+        useStdlibCache -> object : LoweringsCacheProvider {
+            override fun cacheByPath(path: String): SerializedIcData? {
+                return icCache[path]
+            }
+        }
+        useGlobalSignatures -> EmptyLoweringsCacheProvider
+        else -> null
+    }
+
+    val (moduleFragment: IrModuleFragment, dependencyModules, irBuiltIns, symbolTable, deserializer, moduleToName, loweredIrLoaded) =
+        loadIr(project, mainModule, analyzer, configuration, allDependencies, friendDependencies, irFactory, cacheProvider)
+
+    val moduleDescriptor = moduleFragment.descriptor
+
+    val allModules = when (mainModule) {
+        is MainModule.SourceFiles -> dependencyModules + listOf(moduleFragment)
+        is MainModule.Klib -> dependencyModules
+    }
+
+    val context = JsIrBackendContext(
+        moduleDescriptor,
+        irBuiltIns,
+        symbolTable,
+        allModules.first(),
+        exportedDeclarations,
+        configuration,
+        es6mode = es6mode,
+        dceRuntimeDiagnostic = dceRuntimeDiagnostic,
+        propertyLazyInitialization = propertyLazyInitialization,
+        mapping = deserializer.mapping,
+    )
+
+    // Load declarations referenced during `context` initialization
+    val irProviders = listOf(deserializer)
+    ExternalDependenciesGenerator(symbolTable, irProviders).generateUnboundSymbolsAsDependencies()
+
+    deserializer.postProcess()
+    symbolTable.noUnboundLeft("Unbound symbols at the end of linker")
+
+    deserializer.loadIcIr { moveBodilessDeclarationsToSeparatePlace(context, it) }
+
+    return PreparedIr(context, deserializer, allModules, moduleToName, loweredIrLoaded)
+}
+
+data class PreparedIr(
+    val context: JsIrBackendContext,
+    val linker: JsIrLinker,
+    val allModules: List<IrModuleFragment>,
+    val moduleToName: Map<IrModuleFragment, String>,
+    val loweredIrLoaded: Set<IrModuleFragment>,
+)

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsExpressionTransformer.kt

@@ -11,10 +11,7 @@ import org.jetbrains.kotlin.ir.backend.js.utils.JsGenerationContext
 import org.jetbrains.kotlin.ir.backend.js.utils.Namer
 import org.jetbrains.kotlin.ir.backend.js.utils.emptyScope
 import org.jetbrains.kotlin.ir.backend.js.utils.getJsNameOrKotlinName
-import org.jetbrains.kotlin.ir.declarations.IrClass
+import org.jetbrains.kotlin.ir.declarations.*
-import org.jetbrains.kotlin.ir.declarations.IrConstructor
-import org.jetbrains.kotlin.ir.declarations.IrSimpleFunction
-import org.jetbrains.kotlin.ir.declarations.IrValueDeclaration
 import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.types.isUnit
 import org.jetbrains.kotlin.ir.util.isEffectivelyExternal
@@ -324,7 +321,7 @@ class IrElementToJsExpressionTransformer : BaseIrElementToJsNodeTransformer<JsEx
             expression.right.accept(this, data)
         )
 
-    private fun IrValueDeclaration.isThisReceiver(): Boolean = when (val p = parent) {
+    private fun IrValueDeclaration.isThisReceiver(): Boolean = this !is IrVariable && when (val p = parent) {
         is IrSimpleFunction -> this === p.dispatchReceiverParameter
         is IrClass -> this === p.thisReceiver
         else -> false

compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrFactory.kt

@@ -9,11 +9,13 @@ import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.expressions.IrBlockBody
+import org.jetbrains.kotlin.ir.expressions.IrBody
 import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.expressions.IrExpressionBody
 import org.jetbrains.kotlin.ir.expressions.persistent.PersistentIrBlockBody
 import org.jetbrains.kotlin.ir.expressions.persistent.PersistentIrExpressionBody
 import org.jetbrains.kotlin.ir.symbols.*
+import org.jetbrains.kotlin.ir.symbols.impl.IrPublicSymbolBase
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.util.IdSignature
 import org.jetbrains.kotlin.name.Name
@@ -24,8 +26,24 @@ class PersistentIrFactory : IrFactory {
 
     override var stageController = StageController()
 
+    val allDeclarations = mutableListOf<IrDeclaration>()
+
+    val allBodies = mutableListOf<IrBody>()
+
+    private fun IrDeclaration.register() {
+        allDeclarations += this
+    }
+
+    fun declarationSignature(declaration: IrDeclaration): IdSignature? {
+        return (declaration as? PersistentIrDeclarationBase<*>)?.signature ?: declaration.symbol.signature
+    }
+
     @Suppress("UNUSED_PARAMETER")
-    fun currentSignature(declaration: IrDeclaration): IdSignature? = null
+    internal fun currentSignature(declaration: IrDeclaration): IdSignature? {
+        val parentSig = stageController.currentDeclaration?.let { declarationSignature(it) } ?: return null
+
+        return stageController.createSignature(parentSig)
+    }
 
     override fun createAnonymousInitializer(
         startOffset: Int,
@@ -34,7 +52,7 @@ class PersistentIrFactory : IrFactory {
         symbol: IrAnonymousInitializerSymbol,
         isStatic: Boolean,
     ): IrAnonymousInitializer =
-        PersistentIrAnonymousInitializer(startOffset, endOffset, origin, symbol, isStatic, this)
+        PersistentIrAnonymousInitializer(startOffset, endOffset, origin, symbol, isStatic, this).also { it.register() }
 
     override fun createClass(
         startOffset: Int,
@@ -58,7 +76,7 @@ class PersistentIrFactory : IrFactory {
             startOffset, endOffset, origin, symbol, name, kind, visibility, modality,
             isCompanion, isInner, isData, isExternal, isInline, isExpect, isFun, source,
             this
-        )
+        ).also { it.register() }
 
     override fun createConstructor(
         startOffset: Int,
@@ -77,7 +95,7 @@ class PersistentIrFactory : IrFactory {
         PersistentIrConstructor(
             startOffset, endOffset, origin, symbol, name, visibility, returnType, isInline, isExternal, isPrimary, isExpect,
             containerSource, this
-        )
+        ).also { it.register() }
 
     override fun createEnumEntry(
         startOffset: Int,
@@ -86,14 +104,14 @@ class PersistentIrFactory : IrFactory {
         symbol: IrEnumEntrySymbol,
         name: Name,
     ): IrEnumEntry =
-        PersistentIrEnumEntry(startOffset, endOffset, origin, symbol, name, this)
+        PersistentIrEnumEntry(startOffset, endOffset, origin, symbol, name, this).also { it.register() }
 
     override fun createErrorDeclaration(
         startOffset: Int,
         endOffset: Int,
         descriptor: DeclarationDescriptor?,
     ): IrErrorDeclaration =
-        PersistentIrErrorDeclaration(startOffset, endOffset, descriptor, this)
+        PersistentIrErrorDeclaration(startOffset, endOffset, descriptor, this).also { it.register() }
 
     override fun createField(
         startOffset: Int,
@@ -107,7 +125,7 @@ class PersistentIrFactory : IrFactory {
         isExternal: Boolean,
         isStatic: Boolean,
     ): IrField =
-        PersistentIrField(startOffset, endOffset, origin, symbol, name, type, visibility, isFinal, isExternal, isStatic, this)
+        PersistentIrField(startOffset, endOffset, origin, symbol, name, type, visibility, isFinal, isExternal, isStatic, this).also { it.register() }
 
     override fun createFunction(
         startOffset: Int,
@@ -132,7 +150,7 @@ class PersistentIrFactory : IrFactory {
             startOffset, endOffset, origin, symbol, name, visibility, modality, returnType,
             isInline, isExternal, isTailrec, isSuspend, isOperator, isInfix, isExpect, isFakeOverride,
             containerSource, this
-        )
+        ).also { it.register() }
 
     override fun createFakeOverrideFunction(
         startOffset: Int,
@@ -153,7 +171,7 @@ class PersistentIrFactory : IrFactory {
         PersistentIrFakeOverrideFunction(
             startOffset, endOffset, origin, name, visibility, modality, returnType,
             isInline, isExternal, isTailrec, isSuspend, isOperator, isInfix, isExpect, this
-        )
+        ).also { it.register() }
 
     override fun createLocalDelegatedProperty(
         startOffset: Int,
@@ -166,7 +184,7 @@ class PersistentIrFactory : IrFactory {
     ): IrLocalDelegatedProperty =
         PersistentIrLocalDelegatedProperty(
             startOffset, endOffset, origin, symbol, name, type, isVar, this
-        )
+        ).also { it.register() }
 
     override fun createProperty(
         startOffset: Int,
@@ -189,7 +207,7 @@ class PersistentIrFactory : IrFactory {
             startOffset, endOffset, origin, symbol, name, visibility, modality,
             isVar, isConst, isLateinit, isDelegated, isExternal, isExpect, isFakeOverride,
             containerSource, this
-        )
+        ).also { it.register() }
 
     override fun createFakeOverrideProperty(
         startOffset: Int,
@@ -209,7 +227,7 @@ class PersistentIrFactory : IrFactory {
             startOffset, endOffset, origin, name, visibility, modality,
             isVar, isConst, isLateinit, isDelegated, isExternal, isExpect,
             this
-        )
+        ).also { it.register() }
 
     override fun createTypeAlias(
         startOffset: Int,
@@ -221,7 +239,7 @@ class PersistentIrFactory : IrFactory {
         isActual: Boolean,
         origin: IrDeclarationOrigin,
     ): IrTypeAlias =
-        PersistentIrTypeAlias(startOffset, endOffset, symbol, name, visibility, expandedType, isActual, origin, this)
+        PersistentIrTypeAlias(startOffset, endOffset, symbol, name, visibility, expandedType, isActual, origin, this).also { it.register() }
 
     override fun createTypeParameter(
         startOffset: Int,
@@ -233,7 +251,7 @@ class PersistentIrFactory : IrFactory {
         isReified: Boolean,
         variance: Variance,
     ): IrTypeParameter =
-        PersistentIrTypeParameter(startOffset, endOffset, origin, symbol, name, index, isReified, variance, this)
+        PersistentIrTypeParameter(startOffset, endOffset, origin, symbol, name, index, isReified, variance, this).also { it.register() }
 
     override fun createValueParameter(
         startOffset: Int,
@@ -251,44 +269,56 @@ class PersistentIrFactory : IrFactory {
     ): IrValueParameter =
         PersistentIrValueParameter(
             startOffset, endOffset, origin, symbol, name, index, type, varargElementType, isCrossinline, isNoinline, isHidden, isAssignable, this
-        )
+        ).also { it.register() }
 
     override fun createExpressionBody(
         startOffset: Int,
         endOffset: Int,
         initializer: IrExpressionBody.() -> Unit,
     ): IrExpressionBody =
-        PersistentIrExpressionBody(startOffset, endOffset, this, initializer)
+        PersistentIrExpressionBody(startOffset, endOffset, this, initializer).also {
+            allBodies += it
+        }
 
     override fun createExpressionBody(
         startOffset: Int,
         endOffset: Int,
         expression: IrExpression,
     ): IrExpressionBody =
-        PersistentIrExpressionBody(startOffset, endOffset, expression, this)
+        PersistentIrExpressionBody(startOffset, endOffset, expression, this).also {
+            allBodies += it
+        }
 
     override fun createExpressionBody(
         expression: IrExpression,
     ): IrExpressionBody =
-        PersistentIrExpressionBody(expression, this)
+        PersistentIrExpressionBody(expression, this).also {
+            allBodies += it
+        }
 
     override fun createBlockBody(
         startOffset: Int,
         endOffset: Int,
     ): IrBlockBody =
-        PersistentIrBlockBody(startOffset, endOffset, this)
+        PersistentIrBlockBody(startOffset, endOffset, this).also {
+            allBodies += it
+        }
 
     override fun createBlockBody(
         startOffset: Int,
         endOffset: Int,
         statements: List<IrStatement>,
     ): IrBlockBody =
-        PersistentIrBlockBody(startOffset, endOffset, statements, this)
+        PersistentIrBlockBody(startOffset, endOffset, statements, this).also {
+            allBodies += it
+        }
 
     override fun createBlockBody(
         startOffset: Int,
         endOffset: Int,
         initializer: IrBlockBody.() -> Unit,
     ): IrBlockBody =
-        PersistentIrBlockBody(startOffset, endOffset, this, initializer)
+        PersistentIrBlockBody(startOffset, endOffset, this, initializer).also {
+            allBodies += it
+        }
 }

compiler/ir/serialization.js/build.gradle.kts

@@ -8,6 +8,8 @@ dependencies {
     api(project(":compiler:ir.serialization.common"))
     api(project(":js:js.frontend"))
     implementation(project(":compiler:ir.backend.common"))
+    compile(project(":compiler:ir.tree.persistent"))
+    compileOnly(project(":kotlin-reflect-api"))
 
     compileOnly(intellijCoreDep()) { includeJars("intellij-core") }
 }

compiler/ir/serialization.js/src/org/jetbrains/kotlin/ir/backend/js/ic/IcFileDeserializer.kt

@@ -0,0 +1,313 @@
+/*
+ * 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.ir.backend.js.ic
+
+import org.jetbrains.kotlin.backend.common.overrides.DefaultFakeOverrideClassFilter
+import org.jetbrains.kotlin.backend.common.serialization.*
+import org.jetbrains.kotlin.backend.common.serialization.encodings.BinarySymbolData
+import org.jetbrains.kotlin.descriptors.ModuleDescriptor
+import org.jetbrains.kotlin.ir.backend.js.JsMappingState
+import org.jetbrains.kotlin.ir.backend.js.JsStatementOrigins
+import org.jetbrains.kotlin.ir.backend.js.lower.serialization.ir.JsIrLinker
+import org.jetbrains.kotlin.ir.declarations.IrDeclaration
+import org.jetbrains.kotlin.ir.declarations.IrFile
+import org.jetbrains.kotlin.ir.expressions.IrStatementOriginImpl
+import org.jetbrains.kotlin.ir.serialization.CarrierDeserializer
+import org.jetbrains.kotlin.ir.symbols.IrSymbol
+import org.jetbrains.kotlin.ir.util.IdSignature
+import org.jetbrains.kotlin.library.SerializedIrFile
+import org.jetbrains.kotlin.library.impl.DeclarationId
+import org.jetbrains.kotlin.library.impl.DeclarationIrTableMemoryReader
+import org.jetbrains.kotlin.library.impl.IrArrayMemoryReader
+import org.jetbrains.kotlin.library.impl.IrLongArrayMemoryReader
+import org.jetbrains.kotlin.protobuf.ExtensionRegistryLite
+import org.jetbrains.kotlin.backend.common.serialization.proto.IrFile as ProtoIrFile
+
+class IcFileDeserializer(
+    val linker: JsIrLinker,
+    file: IrFile,
+    originalFileReader: IrLibraryFile,
+    fileProto: org.jetbrains.kotlin.backend.common.serialization.proto.IrFile,
+    deserializeBodies: Boolean,
+    allowErrorNodes: Boolean,
+    deserializeInlineFunctions: Boolean,
+    val moduleDeserializer: IrModuleDeserializer,
+    useGlobalSignatures: Boolean,
+    val handleNoModuleDeserializerFound: (IdSignature, ModuleDescriptor, Collection<IrModuleDeserializer>) -> IrModuleDeserializer,
+    val originalEnqueue: IdSignature.(IcFileDeserializer) -> Unit,
+    val icFileData: SerializedIcDataForFile,
+    val mappingState: JsMappingState,
+    val publicSignatureToIcFileDeserializer: MutableMap<IdSignature, IcFileDeserializer>,
+    val enqueue: IdSignature.(IcFileDeserializer) -> Unit,
+) {
+
+    val originalSymbolDeserializer =
+        IrSymbolDeserializer(
+            linker.symbolTable,
+            originalFileReader,
+            file.symbol,
+            fileProto.actualList,
+            { idSig ->
+                idSig.enqueue(this)
+                if (idSig.hasTopLevel) {
+                    idSig.topLevelSignature().originalEnqueue(this)
+                }
+            },
+            linker::handleExpectActualMapping,
+            useGlobalSignatures = useGlobalSignatures,
+            enqueueAllDeclarations = true,
+            deserializePublicSymbol = ::deserializeOriginalPublicSymbol,
+        )
+
+    private val originalDeclarationDeserializer = IrDeclarationDeserializer(
+        linker.builtIns,
+        linker.symbolTable,
+        linker.symbolTable.irFactory,
+        originalFileReader,
+        file,
+        allowErrorNodes,
+        deserializeInlineFunctions,
+        deserializeBodies,
+        originalSymbolDeserializer,
+        linker.fakeOverrideBuilder.platformSpecificClassFilter,
+        linker.fakeOverrideBuilder,
+        allowRedeclaration = true,
+    )
+
+    private fun deserializeOriginalPublicSymbol(idSig: IdSignature, symbolKind: BinarySymbolData.SymbolKind): IrSymbol {
+        assert(idSig.isPublic)
+
+        val topLevelSig = idSig.topLevelSignature()
+
+        if (idSig in originalFileDeserializer.reversedSignatureIndex) {
+            topLevelSig.originalEnqueue(this)
+            idSig.enqueue(this)
+            linker.modulesWithReachableTopLevels.add(moduleDeserializer)
+
+            return originalFileDeserializer.symbolDeserializer.deserializeIrSymbol(idSig, symbolKind).also {
+                linker.deserializedSymbols.add(it)
+            }
+        } else {
+
+            val actualModuleDeserializer =
+                moduleDeserializer.findModuleDeserializerForTopLevelId(topLevelSig) ?: handleNoModuleDeserializerFound(
+                    idSig,
+                    moduleDeserializer.moduleDescriptor,
+                    moduleDeserializer.moduleDependencies
+                )
+
+            return actualModuleDeserializer.deserializeIrSymbol(idSig, symbolKind)
+        }
+    }
+
+    val originalFileDeserializer = IrFileDeserializer(file, originalFileReader, fileProto, originalSymbolDeserializer, originalDeclarationDeserializer)
+
+    val originalVisited = HashSet<IdSignature>()
+
+    val originalSignatureQueue = ArrayDeque<IdSignature>() // Top-level signatures to be deserialized from original KLIB
+
+    // Returns whether this file should be queued for deserialization
+    fun enqueueForDeserialization(idSig: IdSignature): Boolean {
+        if (originalVisited.add(idSig)) {
+            originalSignatureQueue.addLast(idSig)
+            return originalSignatureQueue.size == 1
+        }
+
+        return false
+    }
+
+    fun deserializePendingSignatures() {
+        while (!originalSignatureQueue.isEmpty()) {
+            val signature = originalSignatureQueue.removeFirst()
+            deserializeAnyDeclaration(signature)
+        }
+    }
+
+    // Explicitly exported declarations (e.g. top-level initializers) must be deserialized before all other declarations.
+    // Thus we schedule their deserialization in deserializer's constructor.
+    val explicitlyExportedToCompiler: Collection<IdSignature> = fileProto.explicitlyExportedToCompilerList.map {
+        val symbolData = originalSymbolDeserializer.parseSymbolData(it)
+        originalSymbolDeserializer.deserializeIdSignature(symbolData.signatureId)
+    }
+
+    fun allOriginalDeclarationSignatures(): Collection<IdSignature> = originalFileDeserializer.reversedSignatureIndex.keys
+
+    // IC data processing starts here
+
+    private val icFileReader = FileReaderFromSerializedIrFile(icFileData.file)
+
+    val symbolDeserializer = IrSymbolDeserializer(
+        linker.symbolTable,
+        icFileReader,
+        file.symbol,
+        emptyList(),
+        { idSig -> enqueueLocalTopLevelDeclaration(idSig) },
+        { _, s -> s },
+        enqueueAllDeclarations = true,
+        useGlobalSignatures = true,
+        deserializedSymbols = originalFileDeserializer.symbolDeserializer.deserializedSymbols,
+        ::deserializePublicSymbol
+    )
+
+    private val declarationDeserializer = IrDeclarationDeserializer(
+        linker.builtIns,
+        linker.symbolTable,
+        linker.symbolTable.irFactory,
+        icFileReader,
+        file,
+        allowErrorNodes = true,
+        deserializeInlineFunctions = true,
+        deserializeBodies = true,
+        symbolDeserializer,
+        DefaultFakeOverrideClassFilter,
+        linker.fakeOverrideBuilder,
+        skipMutableState = true,
+        additionalStatementOriginIndex = additionalStatementOriginIndex,
+        allowErrorStatementOrigins = true,
+        allowRedeclaration = true,
+    )
+
+    private val protoFile: ProtoIrFile by lazy { ProtoIrFile.parseFrom(icFileData.file.fileData.codedInputStream, ExtensionRegistryLite.newInstance()) }
+
+    private val carrierDeserializer by lazy { CarrierDeserializer(declarationDeserializer, icFileData.carriers) }
+
+    val reversedSignatureIndex: Map<IdSignature, Int> by lazy { protoFile.declarationIdList.map { symbolDeserializer.deserializeIdSignature(it) to it }.toMap() }
+
+    val visited = HashSet<IdSignature>()
+
+    val mappingsDeserializer by lazy {
+        mappingState.mappingsDeserializer(icFileData.mappings, { code ->
+            val symbolData = symbolDeserializer.parseSymbolData(code)
+            symbolDeserializer.deserializeIdSignature(symbolData.signatureId)
+        }) {
+            deserializeIrSymbol(it)
+        }
+    }
+
+    fun init() {
+        reversedSignatureIndex.keys.forEach {
+            publicSignatureToIcFileDeserializer[it] = this
+        }
+    }
+
+    private val containerSigToOrder by lazy {
+        mutableMapOf<IdSignature, ByteArray>().also { map ->
+            val containerIds = IrLongArrayMemoryReader(icFileData.order.containerSignatures).array
+            val declarationIds = IrArrayMemoryReader(icFileData.order.declarationSignatures)
+
+            containerIds.forEachIndexed { index, id ->
+                val symbolData = symbolDeserializer.parseSymbolData(id)
+                val containerSig = symbolDeserializer.deserializeIdSignature(symbolData.signatureId)
+
+                map[containerSig] = declarationIds.tableItemBytes(index)
+            }
+        }
+    }
+
+    fun loadClassOrder(classSignature: IdSignature): List<IrSymbol>? {
+        val bytes = containerSigToOrder[classSignature] ?: return null
+
+        return IrLongArrayMemoryReader(bytes).array.map(::deserializeIrSymbol)
+    }
+
+
+    private fun deserializePublicSymbol(idSig: IdSignature, kind: BinarySymbolData.SymbolKind) : IrSymbol {
+        // TODO: reference lowered declarations cross-module
+        val topLevelSig = idSig.topLevelSignature()
+        val actualModuleDeserializer =
+            moduleDeserializer.findModuleDeserializerForTopLevelId(topLevelSig) ?:
+                handleNoModuleDeserializerFound(
+                idSig,
+                moduleDeserializer.moduleDescriptor,
+                moduleDeserializer.moduleDependencies
+            )
+
+        return actualModuleDeserializer.deserializeIrSymbol(idSig, kind)
+    }
+
+    private fun enqueueLocalTopLevelDeclaration(idSig: IdSignature) {
+        // We only care about declarations from IC cache. They all are in the map.
+        val deser = publicSignatureToIcFileDeserializer[idSig] ?: return
+        idSig.enqueue(deser)
+    }
+
+    fun deserializeDeclaration(idSig: IdSignature): IrDeclaration? {
+        cachedDeclaration(idSig)?.let { return it }
+
+        val idSigIndex = reversedSignatureIndex[idSig] ?: return null
+        val declarationStream = icFileReader.irDeclaration(idSigIndex).codedInputStream
+        val declarationProto = org.jetbrains.kotlin.backend.common.serialization.proto.IrDeclaration.parseFrom(declarationStream, ExtensionRegistryLite.newInstance())
+        return declarationDeserializer.deserializeDeclaration(declarationProto)
+    }
+
+    // Return declaration iff it was already deserialized
+    private fun cachedDeclaration(idSig: IdSignature): IrDeclaration? {
+        val symbol = symbolDeserializer.deserializedSymbols[idSig] // Same map is used for both symbol deserializers
+
+        if (symbol != null && symbol.isBound) return symbol.owner as? IrDeclaration
+
+        return null
+    }
+
+    fun deserializeAnyDeclaration(idSig: IdSignature): IrDeclaration? {
+        if (idSig is IdSignature.FileSignature) return null // TODO: is it needed
+
+        cachedDeclaration(idSig)?.let { return it }
+
+        // TODO fast path?
+        val maybeTopLevel = if (!idSig.isLocal || idSig.hasTopLevel) idSig.topLevelSignature() else idSig
+
+        if (maybeTopLevel in originalFileDeserializer.reversedSignatureIndex.keys) {
+            originalFileDeserializer.deserializeFileImplicitDataIfFirstUse()
+            originalFileDeserializer.deserializeDeclaration(maybeTopLevel)
+
+            // At this point the declaration should've been deserialized
+            return cachedDeclaration(idSig) // Will be null in case of fake overrides
+        } else if (maybeTopLevel in reversedSignatureIndex) {
+            return deserializeDeclaration(maybeTopLevel)
+        }
+
+        // TODO: error?
+        return null
+    }
+
+    fun deserializeIrSymbol(code: Long): IrSymbol {
+        return symbolDeserializer.deserializeIrSymbol(code)
+    }
+
+    fun deserializeIrSymbol(idSig: IdSignature, symbolKind: BinarySymbolData.SymbolKind): IrSymbol {
+        idSig.enqueue(this)
+        return symbolDeserializer.deserializeIrSymbol(idSig, symbolKind)
+    }
+
+    fun injectCarriers(declaration: IrDeclaration, signature: IdSignature) {
+        carrierDeserializer.injectCarriers(declaration, signature)
+    }
+
+    companion object {
+        private val additionalStatementOrigins = JsStatementOrigins::class.nestedClasses.toList()
+        private val additionalStatementOriginIndex =
+            additionalStatementOrigins.mapNotNull { it.objectInstance as? IrStatementOriginImpl }.associateBy { it.debugName }
+    }
+}
+
+private class FileReaderFromSerializedIrFile(val irFile: SerializedIrFile) : IrLibraryFile() {
+    private val declarationReader = DeclarationIrTableMemoryReader(irFile.declarations)
+    private val typeReader = IrArrayMemoryReader(irFile.types)
+    private val signatureReader = IrArrayMemoryReader(irFile.signatures)
+    private val stringReader = IrArrayMemoryReader(irFile.strings)
+    private val bodyReader = IrArrayMemoryReader(irFile.bodies)
+
+    override fun irDeclaration(index: Int): ByteArray = declarationReader.tableItemBytes(DeclarationId(index))
+
+    override fun type(index: Int): ByteArray = typeReader.tableItemBytes(index)
+
+    override fun signature(index: Int): ByteArray = signatureReader.tableItemBytes(index)
+
+    override fun string(index: Int): ByteArray = stringReader.tableItemBytes(index)
+
+    override fun body(index: Int): ByteArray = bodyReader.tableItemBytes(index)
+}

compiler/ir/serialization.js/src/org/jetbrains/kotlin/ir/backend/js/ic/IcModuleDeserializer.kt

@@ -0,0 +1,271 @@
+/*
+ * 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.ir.backend.js.ic
+
+import org.jetbrains.kotlin.backend.common.serialization.*
+import org.jetbrains.kotlin.backend.common.serialization.encodings.BinarySymbolData
+import org.jetbrains.kotlin.descriptors.ModuleDescriptor
+import org.jetbrains.kotlin.ir.backend.js.JsMapping
+import org.jetbrains.kotlin.ir.backend.js.lower.serialization.ir.JsIrLinker
+import org.jetbrains.kotlin.ir.declarations.*
+import org.jetbrains.kotlin.ir.declarations.impl.IrModuleFragmentImpl
+import org.jetbrains.kotlin.ir.declarations.persistent.PersistentIrFactory
+import org.jetbrains.kotlin.ir.symbols.IrFileSymbol
+import org.jetbrains.kotlin.ir.symbols.IrPropertySymbol
+import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol
+import org.jetbrains.kotlin.ir.symbols.IrSymbol
+import org.jetbrains.kotlin.ir.util.IdSignature
+import org.jetbrains.kotlin.ir.util.isEffectivelyExternal
+import org.jetbrains.kotlin.library.IrLibrary
+import org.jetbrains.kotlin.library.impl.IrLongArrayMemoryReader
+import org.jetbrains.kotlin.protobuf.ExtensionRegistryLite
+
+import org.jetbrains.kotlin.backend.common.serialization.proto.IrFile as ProtoFile
+
+class IcModuleDeserializer(
+    val irFactory: PersistentIrFactory,
+    val mapping: JsMapping,
+    val linker: JsIrLinker,
+    val icData: SerializedIcData,
+    moduleDescriptor: ModuleDescriptor,
+    override val klib: IrLibrary,
+    override val strategy: DeserializationStrategy,
+    private val containsErrorCode: Boolean = false,
+    private val useGlobalSignatures: Boolean = false,
+) : IrModuleDeserializer(moduleDescriptor) {
+
+    private val fileToDeserializerMap = mutableMapOf<IrFile, IrFileDeserializer>()
+
+    internal val moduleReversedFileIndex = mutableMapOf<IdSignature, IcFileDeserializer>()
+    internal val icModuleReversedFileIndex = mutableMapOf<IdSignature, IcFileDeserializer>()
+
+    override val moduleDependencies by lazy {
+        moduleDescriptor.allDependencyModules.filter { it != moduleDescriptor }.map { linker.resolveModuleDeserializer(it, null) }
+    }
+
+    override fun fileDeserializers(): Collection<IrFileDeserializer> {
+        return fileToDeserializerMap.values
+    }
+
+    override fun init(delegate: IrModuleDeserializer) {
+        val fileCount = klib.fileCount()
+
+        val files = ArrayList<IrFile>(fileCount)
+
+        for (i in 0 until fileCount) {
+            val fileStream = klib.file(i).codedInputStream
+            val fileProto = ProtoFile.parseFrom(fileStream, ExtensionRegistryLite.newInstance())
+            files.add(deserializeIrFile(fileProto, i, delegate, containsErrorCode))
+        }
+
+        moduleFragment.files.addAll(files)
+
+        fileToDeserializerMap.values.forEach { it.symbolDeserializer.deserializeExpectActualMapping() }
+    }
+
+    private fun IrSymbolDeserializer.deserializeExpectActualMapping() {
+        actuals.forEach {
+            val expectSymbol = parseSymbolData(it.expectSymbol)
+            val actualSymbol = parseSymbolData(it.actualSymbol)
+
+            val expect = deserializeIdSignature(expectSymbol.signatureId)
+            val actual = deserializeIdSignature(actualSymbol.signatureId)
+
+            assert(linker.expectUniqIdToActualUniqId[expect] == null) {
+                "Expect signature $expect is already actualized by ${linker.expectUniqIdToActualUniqId[expect]}, while we try to record $actual"
+            }
+            linker.expectUniqIdToActualUniqId[expect] = actual
+            // Non-null only for topLevel declarations.
+            findModuleDeserializerForTopLevelId(actual)?.let { md -> linker.topLevelActualUniqItToDeserializer[actual] = md }
+        }
+    }
+
+    override fun referenceSimpleFunctionByLocalSignature(file: IrFile, idSignature: IdSignature): IrSimpleFunctionSymbol =
+        fileToDeserializerMap[file]?.symbolDeserializer?.referenceSimpleFunctionByLocalSignature(idSignature)
+            ?: error("No deserializer for file $file in module ${moduleDescriptor.name}")
+
+    override fun referencePropertyByLocalSignature(file: IrFile, idSignature: IdSignature): IrPropertySymbol =
+        fileToDeserializerMap[file]?.symbolDeserializer?.referencePropertyByLocalSignature(idSignature)
+            ?: error("No deserializer for file $file in module ${moduleDescriptor.name}")
+
+    // TODO: fix to topLevel checker
+    override fun contains(idSig: IdSignature): Boolean = idSig in moduleReversedFileIndex || idSig in icModuleReversedFileIndex
+
+    override fun deserializeIrSymbol(idSig: IdSignature, symbolKind: BinarySymbolData.SymbolKind): IrSymbol {
+        assert(idSig.isPublic)
+
+        if (idSig in icModuleReversedFileIndex) {
+            val icDeserializer = icModuleReversedFileIndex[idSig]!!
+            return icDeserializer.deserializeIrSymbol(idSig, symbolKind)
+        }
+
+        val topLevelSignature = idSig.topLevelSignature()
+        val icDeserializer = moduleReversedFileIndex[topLevelSignature]
+            ?: error("No file for $topLevelSignature (@ $idSig) in module $moduleDescriptor")
+
+        topLevelSignature.originalEnqueue(icDeserializer)
+        idSig.enqueue(icDeserializer)
+        linker.modulesWithReachableTopLevels.add(this)
+
+        return icDeserializer.originalFileDeserializer.symbolDeserializer.deserializeIrSymbol(idSig, symbolKind).also {
+            linker.deserializedSymbols.add(it)
+        }
+    }
+
+    override val moduleFragment: IrModuleFragment = IrModuleFragmentImpl(moduleDescriptor, linker.builtIns, emptyList())
+
+    private val pathToIcFileData = icData.files.associateBy {
+        it.file.path
+    }
+
+    private val publicSignatureToIcFileDeserializer = mutableMapOf<IdSignature, IcFileDeserializer>()
+
+    private fun deserializeIrFile(
+        fileProto: ProtoFile,
+        fileIndex: Int,
+        moduleDeserializer: IrModuleDeserializer,
+        allowErrorNodes: Boolean
+    ): IrFile {
+
+        val fileReader = IrLibraryFileFromKlib(moduleDeserializer.klib, fileIndex)
+        val file = fileReader.createFile(moduleFragment, fileProto)
+
+        val icFileData = pathToIcFileData[file.path]!!
+
+        val icDeserializer = IcFileDeserializer(
+            linker,
+            file,
+            fileReader,
+            fileProto,
+            strategy.needBodies,
+            allowErrorNodes,
+            strategy.inlineBodies,
+            moduleDeserializer,
+            useGlobalSignatures,
+            linker::handleNoModuleDeserializerFound,
+            { fileDeserializer -> originalEnqueue(fileDeserializer) },
+            icFileData,
+            mapping.state,
+            publicSignatureToIcFileDeserializer,
+            { fileDeserializer -> enqueue(fileDeserializer) },
+        )
+
+        icDeserializers += icDeserializer
+
+        icDeserializer.explicitlyExportedToCompiler.forEach { it.topLevelSignature().originalEnqueue(icDeserializer) }
+
+        fileToDeserializerMap[file] = icDeserializer.originalFileDeserializer
+
+        val topLevelDeclarations = icDeserializer.originalFileDeserializer.reversedSignatureIndex.keys
+        topLevelDeclarations.forEach {
+            moduleReversedFileIndex.putIfAbsent(it, icDeserializer) // TODO Why not simple put?
+        }
+
+        if (strategy.theWholeWorld) {
+            icDeserializer.allOriginalDeclarationSignatures().forEach { it.originalEnqueue(icDeserializer) }
+        }
+        if (strategy.theWholeWorld || strategy.explicitlyExported) {
+            linker.modulesWithReachableTopLevels.add(this)
+        }
+
+        return file
+    }
+
+    override fun addModuleReachableTopLevel(idSig: IdSignature) {
+        val fileLocalDeserializationState = moduleReversedFileIndex[idSig] ?: error("No file found for key $idSig")
+        idSig.originalEnqueue(fileLocalDeserializationState)
+    }
+
+    override fun deserializeReachableDeclarations() {
+        while (!originalFileQueue.isEmpty()) {
+            originalFileQueue.removeFirst().deserializePendingSignatures()
+        }
+    }
+
+    val originalFileQueue = ArrayDeque<IcFileDeserializer>()
+
+    fun IdSignature.originalEnqueue(fileDeserializer: IcFileDeserializer) {
+        if (fileDeserializer.enqueueForDeserialization(this)) {
+            originalFileQueue.addLast(fileDeserializer)
+        }
+    }
+
+    val fileQueue = ArrayDeque<IcFileDeserializer>()
+    val signatureQueue = ArrayDeque<IdSignature>()
+
+    val icDeserializers = mutableListOf<IcFileDeserializer>()
+    val classToDeclarationSymbols = mutableMapOf<IrClass, List<IrSymbol>>()
+
+    fun IdSignature.enqueue(icDeserializer: IcFileDeserializer) {
+        if (this !in icDeserializer.visited) {
+            fileQueue.addLast(icDeserializer)
+            signatureQueue.addLast(this)
+            icDeserializer.visited += this
+        }
+    }
+
+    override fun postProcess() {
+        icDeserializers.forEach { icDeserializer ->
+            if (!icDeserializer.visited.isEmpty()) {
+                val file = icDeserializer.originalFileDeserializer.file
+                icDeserializer.init()
+                icDeserializer.reversedSignatureIndex.keys.forEach {
+                    if (it in icModuleReversedFileIndex) error("Duplicate signature $it in both ${icModuleReversedFileIndex[it]!!.originalFileDeserializer.file.path} and in ${file.path}")
+
+                    icModuleReversedFileIndex[it] = icDeserializer
+                }
+            }
+        }
+
+        while (signatureQueue.isNotEmpty()) {
+            val icFileDeserializer = fileQueue.removeFirst()
+            val signature = signatureQueue.removeFirst()
+
+            val declaration = icFileDeserializer.deserializeDeclaration(signature) ?: continue
+
+            icFileDeserializer.injectCarriers(declaration, signature)
+
+            icFileDeserializer.mappingsDeserializer(signature, declaration)
+
+            // Make sure all members are loaded
+            if (declaration is IrClass) {
+                icFileDeserializer.loadClassOrder(signature)?.let {
+                    classToDeclarationSymbols[declaration] = it
+                }
+            }
+        }
+
+        irFactory.stageController.withStage(1000) {
+
+            for (icDeserializer in icDeserializers) {
+                val fd = icDeserializer.originalFileDeserializer
+                val order = icDeserializer.icFileData.order
+
+                fd.file.declarations.retainAll { it.isEffectivelyExternal() }
+
+                IrLongArrayMemoryReader(order.topLevelSignatures).array.forEach {
+                    val symbolData = icDeserializer.symbolDeserializer.parseSymbolData(it)
+                    val idSig = icDeserializer.symbolDeserializer.deserializeIdSignature(symbolData.signatureId)
+
+                    // Don't create unbound symbols for top-level declarations we don't need.
+                    if (idSig in icDeserializer.visited) {
+                        val declaration = icDeserializer.deserializeIrSymbol(idSig, symbolData.kind).owner as IrDeclaration
+                        fd.file.declarations += declaration
+                    }
+                }
+            }
+
+            for ((klass, declarations) in classToDeclarationSymbols.entries) {
+                irFactory.stageController.unrestrictDeclarationListsAccess {
+                    klass.declarations.clear()
+                    for (ds in declarations) {
+                        klass.declarations += ds.owner as IrDeclaration
+                    }
+                }
+            }
+        }
+    }
+}

compiler/ir/serialization.js/src/org/jetbrains/kotlin/ir/backend/js/ic/IcSerializer.kt

@@ -0,0 +1,211 @@
+/*
+ * 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.ir.backend.js.ic
+
+import org.jetbrains.kotlin.backend.common.serialization.DeclarationTable
+import org.jetbrains.kotlin.backend.common.serialization.IdSignatureClashTracker
+import org.jetbrains.kotlin.backend.common.serialization.signature.IdSignatureSerializer
+import org.jetbrains.kotlin.backend.common.serialization.signature.PublicIdSignatureComputer
+import org.jetbrains.kotlin.ir.IrElement
+import org.jetbrains.kotlin.ir.backend.js.JsMapping
+import org.jetbrains.kotlin.ir.backend.js.lower.serialization.ir.JsGlobalDeclarationTable
+import org.jetbrains.kotlin.ir.backend.js.lower.serialization.ir.JsIrFileSerializer
+import org.jetbrains.kotlin.ir.backend.js.lower.serialization.ir.JsIrLinker
+import org.jetbrains.kotlin.ir.declarations.*
+import org.jetbrains.kotlin.ir.declarations.persistent.PersistentIrBodyBase
+import org.jetbrains.kotlin.ir.declarations.persistent.PersistentIrDeclarationBase
+import org.jetbrains.kotlin.ir.declarations.persistent.PersistentIrFactory
+import org.jetbrains.kotlin.ir.descriptors.IrBuiltIns
+import org.jetbrains.kotlin.ir.expressions.IrExpressionBody
+import org.jetbrains.kotlin.ir.serialization.serializeCarriers
+import org.jetbrains.kotlin.ir.symbols.IrSymbol
+import org.jetbrains.kotlin.ir.util.*
+import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
+import org.jetbrains.kotlin.ir.visitors.acceptChildrenVoid
+import org.jetbrains.kotlin.ir.visitors.acceptVoid
+import org.jetbrains.kotlin.library.impl.IrMemoryArrayWriter
+import org.jetbrains.kotlin.library.impl.IrMemoryLongArrayWriter
+
+class IcSerializer(
+    irBuiltIns: IrBuiltIns,
+    val mappings: JsMapping,
+    val irFactory: PersistentIrFactory,
+    val linker: JsIrLinker,
+    val module: IrModuleFragment
+) {
+
+    private val globalDeclarationTable = JsGlobalDeclarationTable(irBuiltIns)
+
+    fun serializeDeclarations(moduleDeclarations: Iterable<IrDeclaration>): SerializedIcData {
+
+        // TODO serialize body carriers and new bodies as well
+        val moduleDeserializer = linker.moduleDeserializer(module.descriptor)
+
+        val fileToDeserializer = moduleDeserializer.fileDeserializers().associateBy { it.file }
+
+        val filteredDeclarations = moduleDeclarations.filter {
+            when {
+                it.fileOrNull.let { it == null || fileToDeserializer[it] == null } -> false
+                it is IrFakeOverrideFunction -> it.isBound
+                it is IrFakeOverrideProperty -> it.isBound
+                else -> (it.parent as? IrFakeOverrideFunction)?.isBound ?: (it.parent as? IrFakeOverrideProperty)?.isBound ?: true
+            }
+        }
+
+        val filteredBodies = irFactory.allBodies.groupBy {
+            (it as? PersistentIrBodyBase<*>)?.let {
+                if (it.hasContainer) {
+                    it.container.fileOrNull
+                } else null
+            }
+        }
+
+        val dataToSerialize = filteredDeclarations.groupBy {
+            // TODO don't move declarations or effects outside the original file
+            // TODO Or invent a different mechanism for that
+
+            it.file
+        }
+
+        val icData = mutableListOf<SerializedIcDataForFile>()
+
+        for (file in fileToDeserializer.keys) {
+            val fileDeclarations = dataToSerialize[file] ?: emptyList()
+            val bodies = filteredBodies[file] ?: emptyList()
+
+            val fileDeserializer = fileToDeserializer[file]!!
+
+            val symbolToSignature = fileDeserializer.symbolDeserializer.deserializedSymbols.entries.associate { (idSig, symbol) -> symbol to idSig }.toMutableMap()
+
+            val icDeclarationTable = IcDeclarationTable(globalDeclarationTable, irFactory, 1000000, 1000000, symbolToSignature)
+            val fileSerializer = JsIrFileSerializer(
+                linker.messageLogger,
+                icDeclarationTable,
+                mutableMapOf(),
+                skipExpects = true,
+                icMode = true,
+                allowNullTypes = true,
+                allowErrorStatementOrigins = true
+            )
+
+            bodies.forEach { body ->
+                if (body is IrExpressionBody) {
+                    fileSerializer.serializeIrExpressionBody(body.expression)
+                } else {
+                    fileSerializer.serializeIrStatementBody(body)
+                }
+            }
+
+            // Only save newly created declarations
+            val newDeclarations = fileDeclarations.filter { d ->
+                d is PersistentIrDeclarationBase<*> && (d.createdOn > 0 || /*d.isFakeOverride ||*/ (d is IrValueParameter || d is IrTypeParameter) && (d.parent as IrDeclaration).isFakeOverride)
+            }
+
+            val serializedCarriers = fileSerializer.serializeCarriers(
+                fileDeclarations,
+                bodies,
+            ) { declaration ->
+                icDeclarationTable.signatureByDeclaration(declaration)
+            }
+
+            val serializedMappings = mappings.state.serializeMappings(fileDeclarations) { symbol ->
+                fileSerializer.serializeIrSymbol(symbol)
+            }
+
+            val order = storeOrder(file) { symbol ->
+                fileSerializer.serializeIrSymbol(symbol)
+            }
+
+            val serializedIrFile = fileSerializer.serializeDeclarationsForIC(file, newDeclarations)
+
+            icData += SerializedIcDataForFile(
+                serializedIrFile,
+                serializedCarriers,
+                serializedMappings,
+                order,
+            )
+        }
+
+        return SerializedIcData(icData)
+    }
+
+    // Returns precomputed signatures for the newly created declarations. Delegates to the default table otherwise.
+    class IcDeclarationTable(
+        globalDeclarationTable: JsGlobalDeclarationTable,
+        val irFactory: PersistentIrFactory,
+        newLocalIndex: Long,
+        newScopeIndex: Int,
+        val existingMappings: MutableMap<IrSymbol, IdSignature>
+    ) : DeclarationTable(globalDeclarationTable) {
+
+        override val signaturer: IdSignatureSerializer = IdSignatureSerializerWithForIC(globalDeclarationTable.publicIdSignatureComputer, this, newLocalIndex, newScopeIndex)
+
+        override fun signatureByDeclaration(declaration: IrDeclaration): IdSignature {
+            return existingMappings.getOrPut(declaration.symbol) {
+                irFactory.declarationSignature(declaration) ?: super.signatureByDeclaration(declaration)
+            }
+        }
+    }
+}
+
+class IdSignatureSerializerWithForIC(
+    publicSignatureBuilder: PublicIdSignatureComputer,
+    table: DeclarationTable,
+    localIndexOffset: Long = 0,
+    scopeIndexOffset: Int = 0,
+) : IdSignatureSerializer(
+    publicSignatureBuilder,
+    table
+) {
+    init {
+        localIndex = localIndexOffset
+        scopeIndex = scopeIndexOffset
+    }
+
+    override fun IrDeclaration.createFileLocalSignature(parentSignature: IdSignature, localIndex: Long): IdSignature {
+        if (this is IrTypeParameter) {
+            return IdSignature.GlobalFileLocalSignature(parentSignature, 1000_000_000_000L + index, fileOrNull?.path ?: "")
+        }
+        return IdSignature.GlobalFileLocalSignature(parentSignature, localIndex, fileOrNull?.path ?: "")
+    }
+
+    override fun IrDeclaration.createScopeLocalSignature(scopeIndex: Int, description: String): IdSignature {
+        return IdSignature.GlobalScopeLocalDeclaration(scopeIndex, description, fileOrNull?.path ?: "")
+    }
+}
+
+fun storeOrder(file: IrFile, idSigToLong: (IrSymbol) -> Long): SerializedOrder {
+    val topLevelSignatures = mutableListOf<Long>()
+    val containerSignatures = mutableListOf<Long>()
+    val declarationSignatures = mutableListOf<ByteArray>()
+
+    fun IrDeclaration.idSigIndex(): Long = idSigToLong(symbol)
+
+    file.declarations.forEach { d ->
+        topLevelSignatures += d.idSigIndex()
+        d.acceptVoid(object : IrElementVisitorVoid {
+            override fun visitElement(element: IrElement) {
+                element.acceptChildrenVoid(this)
+            }
+
+            override fun visitClass(declaration: IrClass) {
+                // First element is the container signature
+                containerSignatures += declaration.idSigIndex()
+                val declarationIds = declaration.declarations.map { it.idSigIndex() }
+
+                declarationSignatures += IrMemoryLongArrayWriter(declarationIds).writeIntoMemory()
+
+                super.visitClass(declaration)
+            }
+        })
+    }
+
+    return SerializedOrder(
+        IrMemoryLongArrayWriter(topLevelSignatures).writeIntoMemory(),
+        IrMemoryLongArrayWriter(containerSignatures).writeIntoMemory(),
+        IrMemoryArrayWriter(declarationSignatures).writeIntoMemory(),
+    )
+}

compiler/ir/serialization.js/src/org/jetbrains/kotlin/ir/backend/js/ic/IcSymbolTable.kt

@@ -0,0 +1,46 @@
+/*
+ * 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.ir.backend.js.ic
+
+import org.jetbrains.kotlin.ir.declarations.IrFactory
+import org.jetbrains.kotlin.ir.declarations.IrTypeParameter
+import org.jetbrains.kotlin.ir.symbols.IrFieldSymbol
+import org.jetbrains.kotlin.ir.symbols.IrTypeParameterSymbol
+import org.jetbrains.kotlin.ir.symbols.impl.IrFieldPublicSymbolImpl
+import org.jetbrains.kotlin.ir.symbols.impl.IrTypeParameterPublicSymbolImpl
+import org.jetbrains.kotlin.ir.util.IdSignature
+import org.jetbrains.kotlin.ir.util.IdSignatureComposer
+import org.jetbrains.kotlin.ir.util.NameProvider
+import org.jetbrains.kotlin.ir.util.SymbolTable
+
+class IcSymbolTable(
+    signaturer: IdSignatureComposer,
+    irFactory: IrFactory,
+    nameProvider: NameProvider = NameProvider.DEFAULT,
+) : SymbolTable(
+    signaturer,
+    irFactory,
+    nameProvider,
+) {
+    override fun referenceFieldFromLinker(sig: IdSignature): IrFieldSymbol =
+        fieldSymbolTable.run {
+            fieldSymbolTable.referenced(sig) { IrFieldPublicSymbolImpl(sig) }
+        }
+
+    override fun declareGlobalTypeParameter(
+        sig: IdSignature,
+        symbolFactory: () -> IrTypeParameterSymbol,
+        typeParameterFactory: (IrTypeParameterSymbol) -> IrTypeParameter
+    ): IrTypeParameter {
+        return globalTypeParameterSymbolTable.declare(sig, symbolFactory, typeParameterFactory)
+    }
+
+    override fun referenceTypeParameterFromLinker(sig: IdSignature): IrTypeParameterSymbol {
+        return scopedTypeParameterSymbolTable.get(sig) ?: globalTypeParameterSymbolTable.referenced(sig) {
+            IrTypeParameterPublicSymbolImpl(sig)
+        }
+    }
+}

compiler/ir/serialization.js/src/org/jetbrains/kotlin/ir/backend/js/ic/data.kt

@@ -0,0 +1,111 @@
+/*
+ * 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.ir.backend.js.ic
+
+import org.jetbrains.kotlin.ir.backend.js.SerializedMapping
+import org.jetbrains.kotlin.ir.backend.js.SerializedMappings
+import org.jetbrains.kotlin.ir.serialization.SerializedCarriers
+import org.jetbrains.kotlin.library.SerializedIrFile
+import org.jetbrains.kotlin.library.impl.IrArrayMemoryReader
+import org.jetbrains.kotlin.library.impl.IrMemoryArrayWriter
+import org.jetbrains.kotlin.library.impl.toArray
+import java.io.File
+import java.nio.charset.Charset
+
+class SerializedIcData(
+    val files: Collection<SerializedIcDataForFile>,
+)
+
+class SerializedIcDataForFile(
+    val file: SerializedIrFile,
+    val carriers: SerializedCarriers,
+    val mappings: SerializedMappings,
+    val order: SerializedOrder,
+)
+
+class SerializedOrder(
+    val topLevelSignatures: ByteArray,
+    val containerSignatures: ByteArray,
+    val declarationSignatures: ByteArray,
+)
+
+fun SerializedIcData.writeTo(dir: File) {
+    if (!dir.exists()) error("Directory doesn't exist: ${dir.absolutePath}")
+    if (!dir.isDirectory) error("Not a directory: ${dir.absolutePath}")
+
+    files.forEach {
+        val fqnPath = it.file.fqName
+        val fileId = it.file.path.hashCode().toString(Character.MAX_RADIX)
+        val irFileDirectory = "ic-$fqnPath.$fileId.file"
+        val fileDir = File(dir, irFileDirectory)
+
+        // TODO: just rewrite?
+        if (!fileDir.exists()) {
+            if (!fileDir.mkdirs()) error("Failed to create output dir for file ${fileDir.absolutePath}")
+        }
+
+        // .file
+        File(fileDir, "file.fileData").writeBytes(it.file.fileData)
+        File(fileDir, "file.path").writeBytes(it.file.path.toByteArray(Charsets.UTF_8))
+        File(fileDir, "file.declarations").writeBytes(it.file.declarations)
+        File(fileDir, "file.types").writeBytes(it.file.types)
+        File(fileDir, "file.signatures").writeBytes(it.file.signatures)
+        File(fileDir, "file.strings").writeBytes(it.file.strings)
+        File(fileDir, "file.bodies").writeBytes(it.file.bodies)
+        // .carriers
+        File(fileDir, "carriers.signatures").writeBytes(it.carriers.signatures)
+        File(fileDir, "carriers.declarationCarriers").writeBytes(it.carriers.declarationCarriers)
+        File(fileDir, "carriers.bodyCarriers").writeBytes(it.carriers.bodyCarriers)
+        File(fileDir, "carriers.removedOn").writeBytes(it.carriers.removedOn)
+        // .mappings
+        File(fileDir, "mappings.keys").writeBytes(it.mappings.keyBytes())
+        File(fileDir, "mappings.values").writeBytes(it.mappings.valueBytes())
+        // .order
+        File(fileDir, "order.topLevelSignatures").writeBytes(it.order.topLevelSignatures)
+        File(fileDir, "order.containerSignatures").writeBytes(it.order.containerSignatures)
+        File(fileDir, "order.declarationSignatures").writeBytes(it.order.declarationSignatures)
+    }
+}
+
+private fun SerializedMappings.keyBytes() = IrMemoryArrayWriter(mappings.map { it.keys }).writeIntoMemory()
+private fun SerializedMappings.valueBytes() = IrMemoryArrayWriter(mappings.map { it.values }).writeIntoMemory()
+
+fun File.readIcData(): SerializedIcData {
+    if (!this.isDirectory) error("Directory doesn't exist: ${this.absolutePath}")
+
+    return SerializedIcData(this.listFiles()!!.filter { it.isDirectory}.map { fileDir ->
+        val file = SerializedIrFile(
+            fileData = File(fileDir, "file.fileData").readBytes(),
+            fqName = fileDir.name.split('.').dropLast(2).joinToString(separator = "."),
+            path = File(fileDir, "file.path").readBytes().toString(Charsets.UTF_8),
+            types = File(fileDir, "file.types").readBytes(),
+            signatures = File(fileDir, "file.signatures").readBytes(),
+            strings = File(fileDir, "file.strings").readBytes(),
+            bodies = File(fileDir, "file.bodies").readBytes(),
+            declarations = File(fileDir, "file.declarations").readBytes()
+        )
+
+        val carriers = SerializedCarriers(
+            signatures = File(fileDir, "carriers.signatures").readBytes(),
+            declarationCarriers = File(fileDir, "carriers.declarationCarriers").readBytes(),
+            bodyCarriers = File(fileDir, "carriers.bodyCarriers").readBytes(),
+            removedOn = File(fileDir, "carriers.removedOn").readBytes(),
+        )
+
+        val mappingKeys = IrArrayMemoryReader(File(fileDir, "mappings.keys").readBytes()).toArray()
+        val mappingValues = IrArrayMemoryReader(File(fileDir, "mappings.values").readBytes()).toArray()
+        assert(mappingKeys.size == mappingValues.size)
+        val mappings = SerializedMappings(mappingKeys.zip(mappingValues).map { (k, v) -> SerializedMapping(k, v) })
+
+        val order = SerializedOrder(
+            topLevelSignatures = File(fileDir, "order.topLevelSignatures").readBytes(),
+            containerSignatures = File(fileDir, "order.containerSignatures").readBytes(),
+            declarationSignatures = File(fileDir, "order.declarationSignatures").readBytes(),
+        )
+
+        SerializedIcDataForFile(file, carriers, mappings, order)
+    })
+}

compiler/ir/serialization.js/src/org/jetbrains/kotlin/ir/backend/js/klib.kt

@@ -30,6 +30,8 @@ import org.jetbrains.kotlin.descriptors.impl.ModuleDescriptorImpl
 import org.jetbrains.kotlin.incremental.components.LookupTracker
 import org.jetbrains.kotlin.ir.IrBuiltIns
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
+import org.jetbrains.kotlin.ir.backend.js.ic.IcSymbolTable
+import org.jetbrains.kotlin.ir.backend.js.ic.SerializedIcData
 import org.jetbrains.kotlin.ir.backend.js.lower.serialization.ir.JsIrLinker
 import org.jetbrains.kotlin.ir.backend.js.lower.serialization.ir.JsIrModuleSerializer
 import org.jetbrains.kotlin.ir.backend.js.lower.serialization.ir.JsManglerDesc
@@ -167,9 +169,9 @@ fun generateKLib(
     }
 
     val depsDescriptors =
-        ModulesStructure(project, MainModule.SourceFiles(files), analyzer, configuration, dependencies, friendDependencies)
+        ModulesStructure(project, MainModule.SourceFiles(files), analyzer, configuration, dependencies, friendDependencies, EmptyLoweringsCacheProvider)
     val allDependencies = depsDescriptors.allDependencies
-    val (psi2IrContext, hasErrors) = runAnalysisAndPreparePsi2Ir(depsDescriptors, irFactory, errorPolicy)
+    val (psi2IrContext, hasErrors) = runAnalysisAndPreparePsi2Ir(depsDescriptors, SymbolTable(IdSignatureDescriptor(JsManglerDesc), irFactory, errorPolicy)
     val irBuiltIns = psi2IrContext.irBuiltIns
 
     val expectDescriptorToSymbol = mutableMapOf<DeclarationDescriptor, IrSymbol>()
@@ -232,6 +234,7 @@ data class IrModuleInfo(
     val symbolTable: SymbolTable,
     val deserializer: JsIrLinker,
     val moduleFragmentToUniqueName: Map<IrModuleFragment, String>,
+    val loweredIrLoaded: Set<IrModuleFragment> = emptySet(),
 )
 
 private fun sortDependencies(resolvedDependencies: List<KotlinResolvedLibrary>, mapping: Map<KotlinLibrary, ModuleDescriptor>): Collection<KotlinLibrary> {
@@ -244,7 +247,14 @@ private fun sortDependencies(resolvedDependencies: List<KotlinResolvedLibrary>,
     }.reversed()
 }
 
-@OptIn(ObsoleteDescriptorBasedAPI::class)
+interface LoweringsCacheProvider {
+    fun cacheByPath(path: String): SerializedIcData?
+}
+
+object EmptyLoweringsCacheProvider : LoweringsCacheProvider {
+    override fun cacheByPath(path: String): SerializedIcData? = null
+}
+
 fun loadIr(
     project: Project,
     mainModule: MainModule,
@@ -253,16 +263,20 @@ fun loadIr(
     dependencies: Collection<String>,
     friendDependencies: Collection<String>,
     irFactory: IrFactory,
-    verifySignatures: Boolean
+    verifySignatures: Boolean,
+    loweringsCacheProvider: LoweringsCacheProvider? = null
 ): IrModuleInfo {
-    val depsDescriptors = ModulesStructure(project, mainModule, analyzer, configuration, dependencies, friendDependencies)
+    val depsDescriptors = ModulesStructure(project, mainModule, analyzer, configuration, dependencies, friendDependencies, loweringsCacheProvider ?: EmptyLoweringsCacheProvider)
     val errorPolicy = configuration.get(JSConfigurationKeys.ERROR_TOLERANCE_POLICY) ?: ErrorTolerancePolicy.DEFAULT
     val messageLogger = configuration.get(IrMessageLogger.IR_MESSAGE_LOGGER) ?: IrMessageLogger.None
     val allDependencies = depsDescriptors.allDependencies
 
+    val signaturer = IdSignatureDescriptor(JsManglerDesc)
+    val symbolTable = if (loweringsCacheProvider == null) SymbolTable(signaturer, irFactory) else IcSymbolTable(signaturer, irFactory)
+
     when (mainModule) {
         is MainModule.SourceFiles -> {
-            val (psi2IrContext, _) = runAnalysisAndPreparePsi2Ir(depsDescriptors, irFactory, errorPolicy)
+            val (psi2IrContext, _) = runAnalysisAndPreparePsi2Ir(depsDescriptors, errorPolicy, symbolTable)
             val irBuiltIns = psi2IrContext.irBuiltIns
             val symbolTable = psi2IrContext.symbolTable
             val feContext = psi2IrContext.run {
@@ -271,6 +285,16 @@ fun loadIr(
             val moduleFragmentToUniqueName = mutableMapOf<IrModuleFragment, String>()
             val irLinker =
                 JsIrLinker(psi2IrContext.moduleDescriptor, messageLogger, irBuiltIns, symbolTable, feContext, null)
+                JsIrLinker(
+                    psi2IrContext.moduleDescriptor,
+                    messageLogger,
+                    irBuiltIns,
+                    symbolTable,
+                    feContext,
+                    null,
+                    depsDescriptors.loweredIcData,
+                    loweringsCacheProvider != null
+                )
             val deserializedModuleFragments = sortDependencies(allDependencies, depsDescriptors.descriptors).map { klib ->
                 irLinker.deserializeIrModuleHeader(
                     depsDescriptors.getModuleDescriptor(klib),
@@ -301,7 +325,8 @@ fun loadIr(
                 (irBuiltIns as IrBuiltInsOverDescriptors).knownBuiltins.forEach { it.acceptVoid(mangleChecker) }
             }
 
-            return IrModuleInfo(moduleFragment, deserializedModuleFragments, irBuiltIns, symbolTable, irLinker, moduleFragmentToUniqueName)
+            return IrModuleInfo(moduleFragment, deserializedModuleFragments, irBuiltIns, symbolTable, irLinker, moduleFragmentToUniqueName,
+                                depsDescriptors.modulesWithCaches(deserializedModuleFragments))
         }
         is MainModule.Klib -> {
             val mainModuleLib = depsDescriptors.allDependencies.find { it.library.libraryFile.canonicalPath == mainModule.libPath }?.library
@@ -313,8 +338,32 @@ fun loadIr(
             val typeTranslator =
                 TypeTranslatorImpl(symbolTable, depsDescriptors.compilerConfiguration.languageVersionSettings, moduleDescriptor)
             val irBuiltIns = IrBuiltInsOverDescriptors(moduleDescriptor.builtIns, typeTranslator, symbolTable)
+
+            val loweredIcData = if (loweringsCacheProvider == null) emptyMap() else {
+                val result = mutableMapOf<ModuleDescriptor, SerializedIcData>()
+
+                for (lib in depsDescriptors.moduleDependencies.keys) {
+                    val path = lib.libraryFile.absolutePath
+                    val icData = loweringsCacheProvider.cacheByPath(path)
+                    if (icData != null) {
+                        result[depsDescriptors.getModuleDescriptor(lib)] = icData
+                    }
+                }
+
+                result
+            }
+
             val irLinker =
-                JsIrLinker(null, messageLogger, irBuiltIns, symbolTable, null, null)
+                JsIrLinker(
+                    null,
+                    messageLogger,
+                    irBuiltIns,
+                    symbolTable,
+                    null,
+                    null,
+                    loweredIcData,
+                    loweringsCacheProvider != null
+                )
 
             val moduleFragmentToUniqueName = mutableMapOf<IrModuleFragment, String>()
 
@@ -338,22 +387,22 @@ fun loadIr(
             ExternalDependenciesGenerator(symbolTable, listOf(irLinker)).generateUnboundSymbolsAsDependencies()
             irLinker.postProcess()
 
-            return IrModuleInfo(moduleFragment, deserializedModuleFragments, irBuiltIns, symbolTable, irLinker, moduleFragmentToUniqueName)
+            return IrModuleInfo(moduleFragment, deserializedModuleFragments, irBuiltIns, symbolTable, irLinker, moduleFragmentToUniqueName,
+                                depsDescriptors.modulesWithCaches(deserializedModuleFragments))
         }
     }
 }
 
 private fun runAnalysisAndPreparePsi2Ir(
     depsDescriptors: ModulesStructure,
-    irFactory: IrFactory,
+    errorIgnorancePolicy: ErrorTolerancePolicy,
-    errorIgnorancePolicy: ErrorTolerancePolicy
+    symbolTable: SymbolTable,
 ): Pair<GeneratorContext, Boolean> {
     val analysisResult = depsDescriptors.runAnalysis(errorIgnorancePolicy)
     val psi2Ir = Psi2IrTranslator(
         depsDescriptors.compilerConfiguration.languageVersionSettings,
         Psi2IrConfiguration(errorIgnorancePolicy.allowErrors)
     )
-    val symbolTable = SymbolTable(IdSignatureDescriptor(JsManglerDesc), irFactory)
     return psi2Ir.createGeneratorContext(
         analysisResult.moduleDescriptor,
         analysisResult.bindingContext,
@@ -426,7 +475,8 @@ private class ModulesStructure(
     private val analyzer: AbstractAnalyzerWithCompilerReport,
     val compilerConfiguration: CompilerConfiguration,
     dependencies: Collection<String>,
-    friendDependenciesPaths: Collection<String>
+    friendDependenciesPaths: Collection<String>,
+    private val loweringsCacheProvider: LoweringsCacheProvider
 ) {
     val allDependencies = jsResolveLibraries(
         dependencies,
@@ -497,6 +547,8 @@ private class ModulesStructure(
     // TODO: these are roughly equivalent to KlibResolvedModuleDescriptorsFactoryImpl. Refactor me.
     val descriptors = mutableMapOf<KotlinLibrary, ModuleDescriptorImpl>()
 
+    val loweredIcData = mutableMapOf<ModuleDescriptor, SerializedIcData>()
+
     fun getModuleDescriptor(current: KotlinLibrary): ModuleDescriptorImpl = descriptors.getOrPut(current) {
         val isBuiltIns = current.unresolvedDependencies.isEmpty()
 
@@ -513,9 +565,18 @@ private class ModulesStructure(
 
         val dependencies = moduleDependencies.getValue(current).map { getModuleDescriptor(it) }
         md.setDependencies(listOf(md) + dependencies)
+
+        loweringsCacheProvider.cacheByPath(current.libraryFile.absolutePath)?.let { icData ->
+            loweredIcData[md] = icData
+        }
+
         md
     }
 
+    fun modulesWithCaches(allModules: Iterable<IrModuleFragment>): Set<IrModuleFragment> {
+        return allModules.filter { it.descriptor in loweredIcData }.toSet()
+    }
+
     val builtInModuleDescriptor =
         if (builtInsDep != null)
             getModuleDescriptor(builtInsDep.library)

compiler/ir/serialization.js/src/org/jetbrains/kotlin/ir/backend/js/lower/serialization/ir/IrIcModuleDeserializerWithBuiltIns.kt

@@ -0,0 +1,66 @@
+/*
+ * 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.ir.backend.js.lower.serialization.ir
+
+import org.jetbrains.kotlin.backend.common.serialization.IrModuleDeserializer
+import org.jetbrains.kotlin.backend.common.serialization.IrModuleDeserializerWithBuiltIns
+import org.jetbrains.kotlin.backend.common.serialization.encodings.BinarySymbolData
+import org.jetbrains.kotlin.backend.common.serialization.knownBuiltins
+import org.jetbrains.kotlin.ir.declarations.IrSimpleFunction
+import org.jetbrains.kotlin.ir.declarations.IrSymbolOwner
+import org.jetbrains.kotlin.ir.declarations.IrTypeParametersContainer
+import org.jetbrains.kotlin.ir.descriptors.IrAbstractFunctionFactory
+import org.jetbrains.kotlin.ir.descriptors.IrBuiltIns
+import org.jetbrains.kotlin.ir.symbols.IrSymbol
+import org.jetbrains.kotlin.ir.util.IdSignature
+
+class IrIcModuleDeserializerWithBuiltIns(
+    builtIns: IrBuiltIns,
+    functionFactory: IrAbstractFunctionFactory,
+    delegate: IrModuleDeserializer,
+) : IrModuleDeserializerWithBuiltIns(builtIns, functionFactory, delegate) {
+
+    override fun additionalBuiltIns(builtIns: IrBuiltIns): Map<IdSignature, IrSymbol> {
+        val result = mutableMapOf<IdSignature, IrSymbol>()
+
+        builtIns.knownBuiltins.forEach {
+            val symbol = (it as IrSymbolOwner).symbol
+            val declaration = symbol.owner
+            if (declaration is IrSimpleFunction) {
+                declaration.typeParameters.forEachIndexed { i, tp ->
+                    result[IdSignature.GlobalFileLocalSignature(symbol.signature!!, 1000_000_000_000L + i, "")] = tp.symbol
+                }
+            }
+        }
+
+        return result
+    }
+
+    override fun checkIsFunctionInterface(idSig: IdSignature): Boolean {
+        if (idSig is IdSignature.GlobalFileLocalSignature) return checkIsFunctionInterface(idSig.container)
+        return super.checkIsFunctionInterface(idSig)
+    }
+
+    override fun contains(idSig: IdSignature): Boolean {
+        return super.contains(idSig) || idSig is IdSignature.GlobalFileLocalSignature && checkIsFunctionInterface(idSig.container)
+    }
+
+    override fun resolveFunctionalInterface(idSig: IdSignature, symbolKind: BinarySymbolData.SymbolKind): IrSymbol {
+        if (idSig is IdSignature.GlobalFileLocalSignature) {
+            val containerSymbolKind = when (idSig.container.asPublic()!!.nameSegments.size) {
+                1 -> BinarySymbolData.SymbolKind.CLASS_SYMBOL
+                3 -> BinarySymbolData.SymbolKind.FUNCTION_SYMBOL
+                else -> error("Cannot infer symbolKind")
+            }
+
+            val declaration = resolveFunctionalInterface(idSig.container, containerSymbolKind).owner as IrTypeParametersContainer
+
+            return declaration.typeParameters[(idSig.id - 1000_000_000_000L).toInt()].symbol
+        }
+
+        return super.resolveFunctionalInterface(idSig, symbolKind)
+    }
+}

compiler/ir/serialization.js/src/org/jetbrains/kotlin/ir/backend/js/lower/serialization/ir/JsDeclarationTable.kt

@@ -14,7 +14,7 @@ import org.jetbrains.kotlin.ir.declarations.IrTypeParameter
 import org.jetbrains.kotlin.ir.util.IdSignature
 import org.jetbrains.kotlin.ir.util.render
 
-class JsUniqIdClashTracker : IdSignatureClashTracker {
+class JsUniqIdClashTracker() : IdSignatureClashTracker {
     private val committedIdSignatures = mutableMapOf<IdSignature, IrDeclaration>()
 
     override fun commit(declaration: IrDeclaration, signature: IdSignature) {
@@ -34,8 +34,8 @@ class JsUniqIdClashTracker : IdSignatureClashTracker {
     }
 }
 
-class JsGlobalDeclarationTable(builtIns: IrBuiltIns) :
+class JsGlobalDeclarationTable(builtIns: IrBuiltIns, tracker: IdSignatureClashTracker = JsUniqIdClashTracker()) :
-    GlobalDeclarationTable(JsManglerIr, JsUniqIdClashTracker()) {
+    GlobalDeclarationTable(JsManglerIr, tracker) {
     init {
         loadKnownBuiltins(builtIns)
     }

compiler/ir/serialization.js/src/org/jetbrains/kotlin/ir/backend/js/lower/serialization/ir/JsIrFileSerializer.kt

@@ -24,6 +24,8 @@ class JsIrFileSerializer(
     skipExpects: Boolean,
     bodiesOnlyForInlines: Boolean = false,
     icMode: Boolean = false,
+    allowNullTypes: Boolean = false,
+    allowErrorStatementOrigins: Boolean = false,
 ) : IrFileSerializer(
     messageLogger,
     declarationTable,
@@ -32,6 +34,8 @@ class JsIrFileSerializer(
     bodiesOnlyForInlines = bodiesOnlyForInlines,
     skipExpects = skipExpects,
     skipMutableState = icMode,
+    allowNullTypes = allowNullTypes,
+    allowErrorStatementOrigins = allowErrorStatementOrigins,
 ) {
     companion object {
         private val JS_EXPORT_FQN = FqName("kotlin.js.JsExport")

compiler/ir/serialization.js/src/org/jetbrains/kotlin/ir/backend/js/lower/serialization/ir/JsIrLinker.kt

@@ -7,10 +7,18 @@ package org.jetbrains.kotlin.ir.backend.js.lower.serialization.ir
 
 import org.jetbrains.kotlin.backend.common.overrides.FakeOverrideBuilder
 import org.jetbrains.kotlin.backend.common.serialization.*
+import org.jetbrains.kotlin.backend.common.serialization.signature.IdSignatureSerializer
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
+import org.jetbrains.kotlin.ir.backend.js.JsMapping
+import org.jetbrains.kotlin.ir.backend.js.ic.IcModuleDeserializer
+import org.jetbrains.kotlin.ir.backend.js.ic.IdSignatureSerializerWithForIC
+import org.jetbrains.kotlin.ir.backend.js.ic.SerializedIcData
 import org.jetbrains.kotlin.ir.IrBuiltIns
 import org.jetbrains.kotlin.ir.builders.TranslationPluginContext
 import org.jetbrains.kotlin.ir.declarations.IrModuleFragment
+import org.jetbrains.kotlin.ir.declarations.persistent.PersistentIrFactory
+import org.jetbrains.kotlin.ir.descriptors.IrAbstractFunctionFactory
+import org.jetbrains.kotlin.ir.descriptors.IrBuiltIns
 import org.jetbrains.kotlin.ir.types.IrTypeSystemContextImpl
 import org.jetbrains.kotlin.ir.util.IrMessageLogger
 import org.jetbrains.kotlin.ir.util.ReferenceSymbolTable
@@ -24,10 +32,15 @@ import org.jetbrains.kotlin.library.containsErrorCode
 class JsIrLinker(
     private val currentModule: ModuleDescriptor?, messageLogger: IrMessageLogger, builtIns: IrBuiltIns, symbolTable: SymbolTable,
     override val translationPluginContext: TranslationPluginContext?,
-    private val icData: ICData? = null
+    private val icData: ICData? = null,
+    private val loweredIcData: Map<ModuleDescriptor, SerializedIcData> = emptyMap(),
+    private val useGlobalSignatures: Boolean = false,
 ) : KotlinIrLinker(currentModule, messageLogger, builtIns, symbolTable, emptyList()) {
 
-    override val fakeOverrideBuilder = FakeOverrideBuilder(this, symbolTable, JsManglerIr, IrTypeSystemContextImpl(builtIns))
+    override val fakeOverrideBuilder = FakeOverrideBuilder(this, symbolTable, JsManglerIr, IrTypeSystemContextImpl(builtIns),
+                                                           signatureSerializerFactory = { publicSignatureBuilder, table ->
+        if (useGlobalSignatures) IdSignatureSerializerWithForIC(publicSignatureBuilder, table) else IdSignatureSerializer(publicSignatureBuilder, table)
+    })
 
     override fun isBuiltInModule(moduleDescriptor: ModuleDescriptor): Boolean =
         moduleDescriptor === moduleDescriptor.builtIns.builtInsModule
@@ -35,13 +48,43 @@ class JsIrLinker(
     private val IrLibrary.libContainsErrorCode: Boolean
         get() = this is KotlinLibrary && this.containsErrorCode
 
-    override fun createModuleDeserializer(moduleDescriptor: ModuleDescriptor, klib: KotlinLibrary?, strategy: DeserializationStrategy): IrModuleDeserializer = klib?.let { lib ->
+    override fun createModuleDeserializer(moduleDescriptor: ModuleDescriptor, klib: IrLibrary?, strategy: DeserializationStrategy): IrModuleDeserializer {
-        JsModuleDeserializer(moduleDescriptor, lib, strategy, lib.versions.abiVersion ?: KotlinAbiVersion.CURRENT, lib.libContainsErrorCode)
+        require(klib != null) { "Expecting kotlin library" }
-    } ?: error("Expecting kotlin library")
+        loweredIcData[moduleDescriptor]?.let { loweredIcData ->
+            return IcModuleDeserializer(
+                symbolTable.irFactory as PersistentIrFactory,
+                mapping,
+                this,
+                loweredIcData,
+                moduleDescriptor,
+                klib,
+                strategy,
+                containsErrorCode = klib.libContainsErrorCode,
+                useGlobalSignatures = useGlobalSignatures
+            )
+        }
+        return klib?.let { lib ->
+            JsModuleDeserializer(moduleDescriptor, lib, strategy, lib.versions.abiVersion ?: KotlinAbiVersion.CURRENT, lib.libContainsErrorCode)
+        } ?: error("Expecting kotlin library")
+    }
 
+    val mapping: JsMapping by lazy { JsMapping(symbolTable.irFactory) }
 
-    private inner class JsModuleDeserializer(moduleDescriptor: ModuleDescriptor, klib: IrLibrary, strategy: DeserializationStrategy, libraryAbiVersion: KotlinAbiVersion, allowErrorCode: Boolean) :
+    private inner class JsModuleDeserializer(moduleDescriptor: ModuleDescriptor, klib: IrLibrary, strategy: DeserializationStrategy, allowErrorCode: Boolean) :
-        BasicIrModuleDeserializer(this, moduleDescriptor, klib, strategy, libraryAbiVersion, allowErrorCode)
+        BasicIrModuleDeserializer(this, moduleDescriptor, klib, strategy, libraryAbiVersion, allowErrorCode, useGlobalSignatures)
+
+    override fun maybeWrapWithBuiltInAndInit(
+        moduleDescriptor: ModuleDescriptor,
+        moduleDeserializer: IrModuleDeserializer
+    ): IrModuleDeserializer {
+        return if (isBuiltInModule(moduleDescriptor)) {
+            if (useGlobalSignatures) {
+                IrIcModuleDeserializerWithBuiltIns(builtIns, functionalInterfaceFactory, moduleDeserializer)
+            } else {
+                IrModuleDeserializerWithBuiltIns(builtIns, functionalInterfaceFactory, moduleDeserializer)
+            }
+        } else moduleDeserializer
+    }
 
     override fun createCurrentModuleDeserializer(moduleFragment: IrModuleFragment, dependencies: Collection<IrModuleDeserializer>): IrModuleDeserializer {
         val currentModuleDeserializer = super.createCurrentModuleDeserializer(moduleFragment, dependencies)
@@ -58,6 +101,20 @@ class JsIrLinker(
             .map { it.moduleFragment }
             .filter { it.descriptor !== currentModule }
 
+
+    fun moduleDeserializer(moduleDescriptor: ModuleDescriptor): IrModuleDeserializer {
+        return deserializersForModules[moduleDescriptor] ?: error("Deserializer for $moduleDescriptor not found")
+    }
+
+    fun loadIcIr(preprocess: (IrModuleFragment) -> Unit) {
+        deserializersForModules.values.forEach {
+            if (it.moduleDescriptor in loweredIcData) {
+                preprocess(it.moduleFragment)
+            }
+            it.postProcess()
+        }
+    }
+
     class JsFePluginContext(
         override val moduleDescriptor: ModuleDescriptor,
         override val symbolTable: ReferenceSymbolTable,

js/js.tests/test/org/jetbrains/kotlin/js/test/BasicIrBoxTest.kt

@@ -10,6 +10,8 @@ import org.jetbrains.kotlin.backend.common.phaser.PhaseConfig
 import org.jetbrains.kotlin.backend.common.phaser.toPhaseMap
 import org.jetbrains.kotlin.cli.common.messages.AnalyzerWithCompilerReport
 import org.jetbrains.kotlin.ir.backend.js.*
+import org.jetbrains.kotlin.ir.backend.js.ic.SerializedIcData
+import org.jetbrains.kotlin.ir.backend.js.ic.prepareSingleLibraryIcCache
 import org.jetbrains.kotlin.ir.declarations.impl.IrFactoryImpl
 import org.jetbrains.kotlin.ir.declarations.persistent.PersistentIrFactory
 import org.jetbrains.kotlin.js.config.JSConfigurationKeys
@@ -29,6 +31,13 @@ private val fullRuntimeKlib: String = System.getProperty("kotlin.js.full.stdlib.
 private val defaultRuntimeKlib = System.getProperty("kotlin.js.reduced.stdlib.path")
 private val kotlinTestKLib = System.getProperty("kotlin.js.kotlin.test.path")
 
+// TODO Cache on FS (requires bootstrap)
+private val predefinedKlibHasIcCache = mutableMapOf<String, SerializedIcData?>(
+    File(fullRuntimeKlib).absolutePath to null,
+    File(kotlinTestKLib).absolutePath to null,
+    File(defaultRuntimeKlib).absolutePath to null
+)
+
 abstract class BasicIrBoxTest(
     pathToTestDir: String,
     testGroupOutputDirPrefix: String,
@@ -49,11 +58,15 @@ abstract class BasicIrBoxTest(
 
     private fun getBoolean(s: String, default: Boolean) = System.getProperty(s)?.let { parseBoolean(it) } ?: default
 
-    private val lowerPerModule: Boolean = getBoolean("kotlin.js.ir.lowerPerModule")
+    private val runIcMode: Boolean = getBoolean("kotlin.js.ir.icMode")
+
+    private val lowerPerModule: Boolean = runIcMode || getBoolean("kotlin.js.ir.lowerPerModule")
+
+    private val klibMainModule: Boolean = false || getBoolean("kotlin.js.ir.klibMainModule")
 
     override val skipRegularMode: Boolean = getBoolean("kotlin.js.ir.skipRegularMode")
 
-    override val runIrDce: Boolean = !lowerPerModule && getBoolean("kotlin.js.ir.dce", true)
+    override val runIrDce: Boolean = getBoolean("kotlin.js.ir.dce", true)
 
     override val runIrPir: Boolean = !lowerPerModule && getBoolean("kotlin.js.ir.pir", true)
 
@@ -108,10 +121,31 @@ abstract class BasicIrBoxTest(
 
         val allKlibPaths = (runtimeKlibs + transitiveLibraries.map {
             compilationCache[it] ?: error("Can't find compiled module for dependency $it")
-        }).map { File(it).absolutePath }
+        }).map { File(it).absolutePath }.toMutableList()
+
+        val klibPath = outputFile.absolutePath.replace("_v5.js", "/")
+
+        if (isMainModule && klibMainModule) {
+            val resolvedLibraries = jsResolveLibraries(allKlibPaths, emptyList(), messageCollectorLogger(MessageCollector.NONE))
+
+            generateKLib(
+                project = config.project,
+                files = filesToCompile,
+                analyzer = AnalyzerWithCompilerReport(config.configuration),
+                configuration = config.configuration,
+                allDependencies = resolvedLibraries,
+                friendDependencies = emptyList(),
+                irFactory = IrFactoryImpl,
+                outputKlibPath = klibPath,
+                nopack = true,
+                null
+            )
+
+            allKlibPaths += File(klibPath).absolutePath
+        }
 
         val actualOutputFile = outputFile.absolutePath.let {
-            if (!isMainModule) it.replace("_v5.js", "/") else it
+            if (!isMainModule) klibPath else it
         }
 
         if (isMainModule) {
@@ -134,11 +168,42 @@ abstract class BasicIrBoxTest(
                 PhaseConfig(jsPhases)
             }
 
+            val mainModule = if (!klibMainModule) {
+                MainModule.SourceFiles(filesToCompile)
+            } else {
+                val mainLib = resolvedLibraries.getFullList().find { it.libraryFile.absolutePath == File(klibPath).absolutePath }!!
+                MainModule.Klib(mainLib)
+            }
+
             if (!skipRegularMode) {
+                val icCache: Map<String, SerializedIcData> = if (!runIcMode) emptyMap() else {
+                    val map = mutableMapOf<String, SerializedIcData>()
+                    for (klibPath in allKlibPaths) {
+                        val icData = predefinedKlibHasIcCache[klibPath] ?: prepareSingleLibraryIcCache(
+                            project = project,
+                            analyzer = AnalyzerWithCompilerReport(config.configuration),
+                            configuration = config.configuration,
+                            library = resolvedLibraries.getFullList()
+                                .single { it.libraryFile.absolutePath == File(klibPath).absolutePath },
+                            dependencies = resolvedLibraries.filterRoots { it.library.libraryFile.absolutePath == File(klibPath).absolutePath },
+                            icCache = map
+                        )
+
+                        if (klibPath in predefinedKlibHasIcCache) {
+                            predefinedKlibHasIcCache[klibPath] = icData
+                        }
+
+                        map[klibPath] = icData
+                    }
+
+                    map
+                }
+
+
                 val irFactory = if (lowerPerModule) PersistentIrFactory() else IrFactoryImpl
                 val compiledModule = compile(
                     project = config.project,
-                    mainModule = MainModule.SourceFiles(filesToCompile),
+                    mainModule = mainModule,
                     analyzer = AnalyzerWithCompilerReport(config.configuration),
                     configuration = config.configuration,
                     phaseConfig = phaseConfig,
@@ -155,7 +220,9 @@ abstract class BasicIrBoxTest(
                     lowerPerModule = lowerPerModule,
                     safeExternalBoolean = safeExternalBoolean,
                     safeExternalBooleanDiagnostic = safeExternalBooleanDiagnostic,
-                    verifySignatures = !skipMangleVerification
+                    verifySignatures = !skipMangleVerification,
+                    useStdlibCache = runIcMode,
+                    icCache = icCache
                 )
 
                 compiledModule.outputs!!.writeTo(outputFile, config)
@@ -172,7 +239,7 @@ abstract class BasicIrBoxTest(
             if (runIrPir && !skipDceDriven) {
                 compile(
                     project = config.project,
-                    mainModule = MainModule.SourceFiles(filesToCompile),
+                    mainModule = mainModule,
                     analyzer = AnalyzerWithCompilerReport(config.configuration),
                     configuration = config.configuration,
                     phaseConfig = phaseConfig,