Add basic support for Kotlin/Native variants to the PM20 Gradle plugin

libraries/tools/kotlin-gradle-plugin-api/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/CinteropSettings.kt

@@ -10,6 +10,7 @@ import org.gradle.api.Action
 import org.gradle.api.Named
 import org.gradle.api.file.FileCollection
 import org.jetbrains.kotlin.gradle.dsl.KotlinCommonOptions
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinCompilationData
 
 interface CInteropSettings : Named {
 
@@ -22,7 +23,7 @@ interface CInteropSettings : Named {
     }
 
     // TODO: Provide an interface for native compilations.
-    val compilation: KotlinCompilation<KotlinCommonOptions>
+    val compilation: KotlinCompilationData<out KotlinCommonOptions>
 
     val dependencyConfigurationName: String
     var dependencyFiles: FileCollection

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinPlugin.kt

@@ -36,7 +36,7 @@ import org.jetbrains.kotlin.gradle.logging.kotlinDebug
 import org.jetbrains.kotlin.gradle.model.builder.KotlinModelBuilder
 import org.jetbrains.kotlin.gradle.plugin.mpp.*
 import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinCompilationData
-import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.isMain
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.isMainCompilationData
 import org.jetbrains.kotlin.gradle.scripting.internal.ScriptingGradleSubplugin
 import org.jetbrains.kotlin.gradle.targets.js.dsl.KotlinJsBinaryMode
 import org.jetbrains.kotlin.gradle.targets.js.ir.*
@@ -281,7 +281,7 @@ internal class Kotlin2JsSourceSetProcessor(
                     kotlinOptions.freeCompilerArgs.contains(PRODUCE_ZIPPED_KLIB)
                 ) {
                     // Configure FQ module name to avoid cyclic dependencies in klib manifests (see KT-36721).
-                    val baseName = if (kotlinCompilation.isMain()) {
+                    val baseName = if (kotlinCompilation.isMainCompilationData()) {
                         project.name
                     } else {
                         "${project.name}_${kotlinCompilation.compilationPurpose}"
@@ -366,7 +366,7 @@ internal class KotlinCommonSourceSetProcessor(
     override fun doTargetSpecificProcessing() {
         project.tasks.named(kotlinCompilation.compileAllTaskName).dependsOn(kotlinTask)
         // can be missing (e.g. in case of tests)
-        if ((kotlinCompilation as? AbstractKotlinCompilation<*>)?.isMain() == true) {
+        if ((kotlinCompilation as? AbstractKotlinCompilation<*>)?.isMainCompilationData() == true) {
             project.locateTask<Task>(kotlinCompilation.target.artifactsTaskName)?.dependsOn(kotlinTask)
         }
 

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/GradleProjectModuleBuilder.kt

@@ -281,11 +281,7 @@ class GradleModuleVariantResolver(val project: Project) : ModuleVariantResolver
 
         val compileClasspath = getCompileDependenciesConfigurationForVariant(project, requestingVariant)
 
-        // TODO optimize O(n) search, store the mapping
+        val dependencyModuleId = dependencyModule.moduleIdentifier
-        val component = compileClasspath.incoming.resolutionResult.allComponents.find { it.id.matchesModule(dependencyModule) }
-            ?: return VariantResolution.NotRequested(requestingVariant, dependencyModule)
-
-        val dependencyModuleId = ModuleIds.fromComponent(project, component)
         // FIXME check composite builds, it's likely that resolvedVariantProvider fails on them?
         val resolvedGradleVariantName = resolvedVariantProvider.getResolvedVariantName(dependencyModuleId, compileClasspath)
         val kotlinVariantName = when (dependencyModule) {
@@ -323,7 +319,7 @@ class GradleModuleVariantResolver(val project: Project) : ModuleVariantResolver
                 project.configurations.getByName(compilation.compileDependencyConfigurationName)
             }
             is KotlinPm20ProjectExtension -> {
-                project.configurations.getByName((requestingVariant as KotlinGradleVariant).compileDependencyConfigurationName)
+                (requestingVariant as KotlinGradleVariant).compileDependencyConfiguration
             }
             else -> error("could not find the compile dependencies configuration for variant $requestingVariant")
         }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/GranularMetadataTransformation.kt

@@ -427,7 +427,7 @@ private class IncludedBuildMetadataExtractor(
         GlobalProjectStructureMetadataStorage.getProjectStructureMetadata(project, id.build.name, id.projectPath)
 }
 
-private open class JarArtifactMppDependencyMetadataExtractor(
+internal open class JarArtifactMppDependencyMetadataExtractor(
     project: Project,
     dependency: ResolvedComponentResult,
     val primaryArtifact: File
@@ -602,7 +602,7 @@ private fun mppDependencyMetadataExtractor(
     return when {
         moduleId is ProjectComponentIdentifier -> when {
             moduleId.build.isCurrentBuild ->
-                ProjectMppDependencyMetadataExtractor(project, actualComponent, project.project(moduleId.projectPath))
+                ProjectMppDependencyMetadataExtractor(project, actualComponent, moduleIdentifier, project.project(moduleId.projectPath))
             metadataArtifact != null ->
                 IncludedBuildMetadataExtractor(project, actualComponent, metadataArtifact)
             else -> null

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/KotlinProjectStructureMetadata.kt

@@ -10,18 +10,16 @@ import com.google.gson.JsonObject
 import com.google.gson.JsonParser
 import com.google.gson.stream.JsonWriter
 import org.gradle.api.Project
-import org.gradle.api.provider.Provider
 import org.gradle.api.tasks.Input
 import org.gradle.api.tasks.Internal
 import org.gradle.api.tasks.Nested
+import org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformExtension
 import org.jetbrains.kotlin.gradle.dsl.multiplatformExtensionOrNull
-import org.jetbrains.kotlin.gradle.dsl.topLevelExtension
 import org.jetbrains.kotlin.gradle.dsl.topLevelExtensionOrNull
 import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinGradleModule
 import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinPm20ProjectExtension
 import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.refinesClosure
 import org.jetbrains.kotlin.gradle.plugin.sources.KotlinDependencyScope
-import org.jetbrains.kotlin.gradle.plugin.sources.withAllDependsOnSourceSets
 import org.jetbrains.kotlin.gradle.plugin.sources.sourceSetDependencyConfigurationByScope
 import org.jetbrains.kotlin.gradle.targets.metadata.dependsOnClosureWithInterCompilationDependencies
 import org.jetbrains.kotlin.gradle.targets.metadata.getPublishedPlatformCompilations
@@ -133,10 +131,7 @@ data class KotlinProjectStructureMetadata(
 
 internal fun buildKotlinProjectStructureMetadata(project: Project): KotlinProjectStructureMetadata? {
     val topLevelExtensionOrNull = project.topLevelExtensionOrNull
-    if (topLevelExtensionOrNull is KotlinPm20ProjectExtension) {
+    require(topLevelExtensionOrNull is KotlinMultiplatformExtension) { "this function only works with the stable plugin" }
-        // FIXME: get module by ID, don't just take the main module
-        return buildProjectStructureMetadata(topLevelExtensionOrNull.main)
-    }
 
     val sourceSetsWithMetadataCompilations =
         project.multiplatformExtensionOrNull?.targets?.getByName(KotlinMultiplatformPlugin.METADATA_TARGET_NAME)?.compilations?.associate {
@@ -195,7 +190,7 @@ internal fun buildProjectStructureMetadata(module: KotlinGradleModule): KotlinPr
     val kotlinFragmentsPerKotlinVariant =
         module.variants.associate { variant -> variant.name to variant.refinesClosure.map { it.name }.toSet() }
     val fragmentRefinesRelation =
-        module.fragments.associate { it.name to it.directRefinesDependencies.map { it.name }.toSet() }
+        module.fragments.associate { it.name to it.directRefinesDependencies.map { it.fragmentName }.toSet() }
 
     // FIXME: support native implementation-as-api-dependencies
     // FIXME: support dependencies on auxiliary modules
@@ -211,7 +206,7 @@ internal fun buildProjectStructureMetadata(module: KotlinGradleModule): KotlinPr
         fragmentRefinesRelation,
         module.fragments.associate { it.name to SourceSetMetadataLayout.KLIB },
         fragmentDependencies,
-        emptySet(),
+        getHostSpecificFragments(module).mapTo(mutableSetOf()) { it.name },
         isPublishedAsRoot = true
     )
 }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/kotlinCompilations.kt

@@ -288,7 +288,7 @@ abstract class AbstractKotlinCompilation<T : KotlinCommonOptions>(
     override val project: Project
         get() = target.project
 
-    override val owner: Any?
+    override val owner: KotlinTarget
         get() = target
 
     override val compilationClassifier: String?

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/DependencyGraphResolver.kt

@@ -39,15 +39,18 @@ class GradleKotlinDependencyGraphResolver(
         configurationToResolveMetadataDependencies(project, requestingModule)
 
     override fun resolveDependencyGraph(requestingModule: KotlinModule): DependencyGraphResolution {
-        if (!requestingModule.representsProject(project))
+        if (requestingModule !is KotlinGradleModule)
             return DependencyGraphResolution.Unknown(requestingModule)
+        return resolveAsGraph(requestingModule)
+    }
 
+    private fun resolveAsGraph(requestingModule: KotlinGradleModule): GradleDependencyGraph {
         val excludeLegacyMetadataModulesFromResult = mutableSetOf<ResolvedComponentResult>()
 
-        val nodeByModuleId = mutableMapOf<KotlinModuleIdentifier, DependencyGraphNode>()
+        val nodeByModuleId = mutableMapOf<KotlinModuleIdentifier, GradleDependencyGraphNode>()
 
-        fun nodeFromComponent(component: ResolvedComponentResult, isRoot: Boolean /*refactor*/): DependencyGraphNode {
+        fun nodeFromComponent(component: ResolvedComponentResult, isRoot: Boolean /*refactor me*/): GradleDependencyGraphNode {
-            val id = component.toModuleIdentifier()
+            val id = component.toSingleModuleIdentifier()
             return nodeByModuleId.getOrPut(id) {
                 val module = if (isRoot)
                     requestingModule
@@ -55,14 +58,20 @@ class GradleKotlinDependencyGraphResolver(
                     .takeIf { component !in excludeLegacyMetadataModulesFromResult }
                     ?: buildSyntheticModule(component, component.variants.singleOrNull()?.displayName ?: "default")
 
-                val componentContainingTransitiveDependencies =
+                val metadataSourceComponent =
                     (module as? ExternalImportedKotlinModule)
                         ?.takeIf { it.hasLegacyMetadataModule }
                         ?.let { (component.dependencies.singleOrNull() as? ResolvedDependencyResult)?.selected }
                         ?: component
 
-                val resolvedComponentDependencies = componentContainingTransitiveDependencies.dependencies
+                val dependenciesRequestedByModule =
+                    module.fragments.flatMap { fragment -> fragment.declaredModuleDependencies.map { it.moduleIdentifier } }.toSet()
+
+                val resolvedComponentDependencies = metadataSourceComponent.dependencies
                     .filterIsInstance<ResolvedDependencyResult>()
+                    // This filter statement is used to only visit the dependencies of the variant(s) of the requested Kotlin module and not
+                    // other variants. This prevents infinite recursion when visiting multiple Kotlin modules within one Gradle components
+                    .filter { dependency -> dependency.requested.toModuleIdentifiers().any { it in dependenciesRequestedByModule } }
                     .flatMap { dependency -> dependency.requested.toModuleIdentifiers().map { id -> id to dependency.selected } }
                     .toMap()
 
@@ -72,13 +81,30 @@ class GradleKotlinDependencyGraphResolver(
                     deps.mapNotNull { resolvedComponentDependencies[it.moduleIdentifier] }.map { nodeFromComponent(it, isRoot = false) }
                 }
 
-                DependencyGraphNode(module, nodeDependenciesMap)
+                GradleDependencyGraphNode(
+                    module,
+                    component,
+                    metadataSourceComponent,
+                    nodeDependenciesMap
+                )
             }
         }
 
-        return DependencyGraphResolution.DependencyGraph(
+        return GradleDependencyGraph(
             requestingModule,
             nodeFromComponent(configurationToResolve(requestingModule).incoming.resolutionResult.root, isRoot = true)
         )
     }
-}
+}
+
+class GradleDependencyGraphNode(
+    override val module: KotlinModule,
+    val selectedComponent: ResolvedComponentResult,
+    val metadataSourceComponent: ResolvedComponentResult?,
+    override val dependenciesByFragment: Map<KotlinModuleFragment, Iterable<GradleDependencyGraphNode>>
+) : DependencyGraphNode(module, dependenciesByFragment)
+
+class GradleDependencyGraph(
+    override val requestingModule: KotlinGradleModule,
+    override val root: GradleDependencyGraphNode
+) : DependencyGraphResolution.DependencyGraph(requestingModule, root)

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/DependencyResolution.kt

@@ -163,7 +163,8 @@ internal class ExternalSyntheticKotlinModule(private val moduleData: BasicKotlin
 
 internal class ExternalImportedKotlinModule(
     private val moduleData: BasicKotlinModule,
-    val projectStructureMetadata: KotlinProjectStructureMetadata
+    val projectStructureMetadata: KotlinProjectStructureMetadata,
+    val hostSpecificFragments: Set<KotlinModuleFragment>
 ) : KotlinModule by moduleData {
     val hasLegacyMetadataModule = !projectStructureMetadata.isPublishedAsRoot
 

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/FragmentGranularMetadataResolver.kt

@@ -51,14 +51,12 @@ internal class FragmentGranularMetadataResolver(
         if (dependencyGraph is DependencyGraphResolution.Unknown)
             error("unexpected failure in dependency graph resolution for $requestingFragment in $project")
 
-        dependencyGraph as DependencyGraphResolution.DependencyGraph
+        dependencyGraph as GradleDependencyGraph // refactor the type hierarchy to avoid this downcast? FIXME?
         val fragmentsToInclude = requestingFragment.refinesClosure
         val requestedDependencies = dependencyGraph.root.dependenciesByFragment.filterKeys { it in fragmentsToInclude }.values.flatten()
 
-        val visited = mutableSetOf<DependencyGraphNode>()
+        val visited = mutableSetOf<GradleDependencyGraphNode>()
-        val fragmentResolutionQueue = ArrayDeque<DependencyGraphNode>().apply {
+        val fragmentResolutionQueue = ArrayDeque<GradleDependencyGraphNode>(requestedDependencies)
-            addAll(requestedDependencies)
-        }
 
         val results = mutableSetOf<MetadataDependencyResolution>()
 
@@ -69,18 +67,15 @@ internal class FragmentGranularMetadataResolver(
             val dependencyModule = dependencyNode.module
 
             val fragmentVisibility = fragmentResolver.getChosenFragments(requestingFragment, dependencyModule)
-            val visibleFragments = (fragmentVisibility as? FragmentResolution.ChosenFragments)?.visibleFragments?.toList().orEmpty()
+            val chosenFragments = fragmentVisibility as? FragmentResolution.ChosenFragments
-            val variantResolutions =
+            val visibleFragments = chosenFragments?.visibleFragments?.toList().orEmpty()
-                (fragmentVisibility as? FragmentResolution.ChosenFragments)?.variantResolutions?.associateBy { it.requestingVariant }
 
             val visibleTransitiveDependencies =
                 dependencyNode.dependenciesByFragment.filterKeys { it in visibleFragments }.values.flattenTo(mutableSetOf())
 
-            //FIXME host-specific fragments
-
             fragmentResolutionQueue.addAll(visibleTransitiveDependencies.filter { it !in visited })
 
-            val resolvedComponentResult = resolvedComponentsByModuleId.getValue(dependencyModule.moduleIdentifier)
+            val resolvedComponentResult = dependencyNode.selectedComponent
             val isResolvedAsProject = resolvedComponentResult.toProjectOrNull(project)
             val result = when (dependencyModule) {
                 is ExternalSyntheticKotlinModule -> {
@@ -90,14 +85,7 @@ internal class FragmentGranularMetadataResolver(
                     val projectStructureMetadata = (dependencyModule as? ExternalImportedKotlinModule)?.projectStructureMetadata
                         ?: checkNotNull(getProjectStructureMetadata(project, resolvedComponentResult, configurationToResolve))
 
-                    // FIXME host-specific metadata!!!
+                    val metadataSourceComponent = dependencyNode.run { metadataSourceComponent ?: selectedComponent }
-
-                    val metadataSourceComponent = when {
-                        dependencyModule is ExternalImportedKotlinModule && dependencyModule.hasLegacyMetadataModule ->
-                            resolvedComponentResult.dependencies.filterIsInstance<ResolvedDependencyResult>().singleOrNull()?.selected
-                                ?: resolvedComponentResult
-                        else -> resolvedComponentResult
-                    }
 
                     val parentResolutionsForDependency =
                         parentResultsByModuleIdentifier[metadataSourceComponent.toSingleModuleIdentifier()].orEmpty()
@@ -106,6 +94,15 @@ internal class FragmentGranularMetadataResolver(
                             .flatMapTo(mutableSetOf()) { it.allVisibleSourceSetNames }
                     val visibleFragmentNames = visibleFragments.map { it.fragmentName }.toSet()
 
+                    val metadataExtractor = getMetadataExtractor(project, resolvedComponentResult, configurationToResolve, true)
+
+                    if (dependencyModule is ExternalImportedKotlinModule &&
+                        metadataExtractor is JarArtifactMppDependencyMetadataExtractor &&
+                        chosenFragments != null
+                    ) {
+                        resolveHostSpecificMetadataArtifacts(dependencyModule, chosenFragments, metadataExtractor)
+                    }
+
                     ChooseVisibleSourceSetsImpl(
                         metadataSourceComponent,
                         isResolvedAsProject,
@@ -113,14 +110,14 @@ internal class FragmentGranularMetadataResolver(
                         visibleFragmentNames,
                         visibleFragmentNames.minus(fragmentsVisibleByParents),
                         visibleTransitiveDependencies.map { resolvedDependenciesByModuleId.getValue(it.module.moduleIdentifier) }.toSet(),
-                        checkNotNull(getMetadataExtractor(project, resolvedComponentResult, configurationToResolve, true))
+                        checkNotNull(metadataExtractor)
                     )
                 }
             }
             results.add(result)
-            fragmentResolutionQueue.addAll(visibleTransitiveDependencies.filterNot(visited::contains))
         }
 
+        // FIXME this code is based on whole components; use module IDs with classifiers instead
         val resultSourceComponents = results.mapTo(mutableSetOf()) { it.dependency }
         resolvedComponentsByModuleId.values.minus(resultSourceComponents).forEach {
             results.add(MetadataDependencyResolution.ExcludeAsUnrequested(it, it.toProjectOrNull(project)))
@@ -128,4 +125,33 @@ internal class FragmentGranularMetadataResolver(
 
         return results
     }
+
+    private fun resolveHostSpecificMetadataArtifacts(
+        dependencyModule: ExternalImportedKotlinModule,
+        chosenFragments: FragmentResolution.ChosenFragments,
+        metadataExtractor: JarArtifactMppDependencyMetadataExtractor
+    ) {
+        val visibleFragments = chosenFragments.visibleFragments
+        val variantResolutions = chosenFragments.variantResolutions
+        val hostSpecificFragments = dependencyModule.hostSpecificFragments
+        val hostSpecificFragmentToArtifact = visibleFragments.intersect(hostSpecificFragments).mapNotNull { hostSpecificFragment ->
+            val relevantResolution = variantResolutions
+                .filterIsInstance<VariantResolution.VariantMatch>()
+                // find some of our variants that resolved a dependency's variant containing the fragment
+                .find { hostSpecificFragment in it.chosenVariant.refinesClosure }
+            // resolve the dependencies of that variant getting the host-specific metadata artifact
+            relevantResolution?.let { resolution ->
+                val variantResolvingPlatformArtifact =
+                    (resolution.requestingVariant as KotlinGradleVariant).compileDependencyConfiguration
+                val configuration = variantResolvingPlatformArtifact
+                val hostSpecificArtifact = ResolvedMppVariantsProvider.get(project)
+                    .getHostSpecificMetadataArtifactByRootModule(
+                        dependencyModule.moduleIdentifier,
+                        configuration
+                    )
+                hostSpecificArtifact?.let { hostSpecificFragment.fragmentName to it }
+            }
+        }
+        metadataExtractor.metadataArtifactBySourceSet.putAll(hostSpecificFragmentToArtifact)
+    }
 }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/GradlePlugin.kt

@@ -17,6 +17,7 @@ import org.jetbrains.kotlin.gradle.internal.customizeKotlinDependencies
 import org.jetbrains.kotlin.gradle.utils.checkGradleCompatibility
 import org.jetbrains.kotlin.project.model.KotlinModuleIdentifier
 import javax.inject.Inject
+import kotlin.reflect.KClass
 
 abstract class KotlinPm20GradlePlugin @Inject constructor(
     @Inject private val softwareComponentFactory: SoftwareComponentFactory
@@ -35,11 +36,28 @@ abstract class KotlinPm20GradlePlugin @Inject constructor(
     }
 
     private fun registerDefaultVariantFactories(project: Project) {
-        project.pm20Extension.modules.configureEach {
+        project.pm20Extension.modules.configureEach { module ->
-            it.fragments.registerFactory(
+            module.fragments.registerFactory(
                 KotlinJvmVariant::class.java,
-                KotlinJvmVariantFactory(it)
+                KotlinJvmVariantFactory(module)
             )
+
+            fun <T: KotlinNativeVariantInternal> registerNativeVariantFactory(variantClass: KClass<T>) {
+                module.fragments.registerFactory(
+                    variantClass.java,
+                    KotlinNativeVariantFactory(module, variantClass)
+                )
+            }
+            listOf(
+                // FIXME codegen, add missing native targets
+                KotlinLinuxX64Variant::class,
+                KotlinMacosX64Variant::class,
+                KotlinMacosArm64Variant::class,
+                KotlinIosX64Variant::class,
+                KotlinIosArm64Variant::class
+            ).forEach { variantClass ->
+                registerNativeVariantFactory(variantClass)
+            }
         }
     }
 

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/KotlinFragmentMetadataCompilationData.kt

@@ -1,115 +0,0 @@
-/*
- * 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.gradle.plugin.mpp.pm20
-
-import org.gradle.api.DefaultTask
-import org.gradle.api.Project
-import org.gradle.api.file.FileCollection
-import org.gradle.api.file.SourceDirectorySet
-import org.gradle.api.plugins.BasePluginConvention
-import org.gradle.api.tasks.TaskProvider
-import org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformCommonOptions
-import org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformCommonOptionsImpl
-import org.jetbrains.kotlin.gradle.dsl.pm20Extension
-import org.jetbrains.kotlin.gradle.plugin.KotlinCompilationOutput
-import org.jetbrains.kotlin.gradle.plugin.KotlinPlatformType
-import org.jetbrains.kotlin.gradle.plugin.LanguageSettingsBuilder
-import org.jetbrains.kotlin.gradle.plugin.mpp.DefaultKotlinCompilationOutput
-import org.jetbrains.kotlin.gradle.plugin.mpp.filterModuleName
-import org.jetbrains.kotlin.gradle.plugin.sources.DefaultLanguageSettingsBuilder
-import org.jetbrains.kotlin.gradle.targets.metadata.ResolvedMetadataFilesProvider
-import org.jetbrains.kotlin.gradle.targets.metadata.createTransformedMetadataClasspath
-import org.jetbrains.kotlin.gradle.utils.getValue
-import org.jetbrains.kotlin.gradle.utils.lowerCamelCaseName
-
-internal class KotlinFragmentMetadataCompilationData(
-    override val project: Project,
-    val fragment: KotlinGradleFragment,
-    private val module: KotlinGradleModule,
-    private val compileAllTask: TaskProvider<DefaultTask>,
-    val metadataCompilationRegistry: MetadataCompilationRegistry,
-    private val resolvedMetadataFiles: Lazy<Iterable<ResolvedMetadataFilesProvider>>
-) : KotlinCompilationData<KotlinMultiplatformCommonOptions> {
-
-    override val owner
-        get() = project.pm20Extension
-
-    override val compilationPurpose: String
-        get() = fragment.fragmentName
-
-    override val compilationClassifier: String
-        get() = lowerCamelCaseName(module.name, "metadata")
-
-    override val kotlinSourceDirectoriesByFragmentName: Map<String, SourceDirectorySet>
-        get() = mapOf(fragment.fragmentName to fragment.kotlinSourceRoots)
-
-    override val compileKotlinTaskName: String
-        get() = lowerCamelCaseName("compile", fragment.disambiguateName(""), "KotlinMetadata")
-
-    override val compileAllTaskName: String
-        get() = compileAllTask.name
-
-    override val compileDependencyFiles: FileCollection by project.provider {
-        createTransformedMetadataClasspath(
-            project,
-            resolvableMetadataConfiguration(fragment.containingModule),
-            lazy { fragment.refinesClosure.minus(fragment).map { metadataCompilationRegistry.byFragment(it).output.classesDirs } },
-            resolvedMetadataFiles
-        )
-    }
-
-    override val output: KotlinCompilationOutput = DefaultKotlinCompilationOutput(
-        project,
-        project.provider { project.buildDir.resolve("processedResources/${fragment.disambiguateName("metadata")}") }
-    )
-
-    override val languageSettings: LanguageSettingsBuilder = DefaultLanguageSettingsBuilder() // FIXME apply settings
-
-    override val platformType: KotlinPlatformType
-        get() = KotlinPlatformType.common
-
-    override val moduleName: String
-        get() { // FIXME deduplicate with ownModuleName
-            val baseName = project.convention.findPlugin(BasePluginConvention::class.java)?.archivesBaseName
-                ?: project.name
-            val suffix = if (module.moduleClassifier == null) "" else "_${module.moduleClassifier}"
-            return filterModuleName("$baseName$suffix")
-        }
-
-    override val ownModuleName: String
-        get() = moduleName
-
-    override val kotlinOptions: KotlinMultiplatformCommonOptions = // FIXME expose for configuration
-        KotlinMultiplatformCommonOptionsImpl()
-
-    override val friendPaths: Iterable<FileCollection>
-        get() = metadataCompilationRegistry.run {
-            fragment.refinesClosure.minus(fragment)
-                .map {
-                    metadataCompilationRegistry.byFragment(it).output.classesDirs
-                }
-        }
-}
-
-internal class MetadataCompilationRegistry {
-    private val compilationDataPerFragment = mutableMapOf<KotlinGradleFragment, KotlinFragmentMetadataCompilationData>()
-
-    fun register(fragment: KotlinGradleFragment, compilationData: KotlinFragmentMetadataCompilationData) {
-        compilationDataPerFragment[fragment]?.let { error("compilation data for fragment $fragment already registered") }
-        compilationDataPerFragment[fragment] = compilationData
-        withAllCallbacks.forEach { it.invoke(compilationData) }
-    }
-
-    fun byFragment(fragment: KotlinGradleFragment): KotlinFragmentMetadataCompilationData =
-        compilationDataPerFragment.getValue(fragment)
-
-    private val withAllCallbacks = mutableListOf<(KotlinFragmentMetadataCompilationData) -> Unit>()
-
-    fun withAll(action: (KotlinFragmentMetadataCompilationData) -> Unit) {
-        compilationDataPerFragment.forEach { action(it.value) }
-        withAllCallbacks += action
-    }
-}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/KotlinJvmVariant.kt

@@ -5,19 +5,11 @@
 
 package org.jetbrains.kotlin.gradle.plugin.mpp.pm20
 
-import org.gradle.api.Project
-import org.gradle.api.file.FileCollection
-import org.gradle.api.file.SourceDirectorySet
 import org.gradle.api.plugins.BasePluginConvention
 import org.jetbrains.kotlin.gradle.dsl.KotlinJvmOptions
 import org.jetbrains.kotlin.gradle.dsl.KotlinJvmOptionsImpl
-import org.jetbrains.kotlin.gradle.dsl.pm20Extension
+import org.jetbrains.kotlin.gradle.plugin.*
-import org.jetbrains.kotlin.gradle.plugin.KotlinCompilationOutput
-import org.jetbrains.kotlin.gradle.plugin.KotlinPlatformType
-import org.jetbrains.kotlin.gradle.plugin.LanguageSettingsBuilder
 import org.jetbrains.kotlin.gradle.plugin.mpp.filterModuleName
-import org.jetbrains.kotlin.gradle.utils.lowerCamelCaseName
-import org.jetbrains.kotlin.project.model.refinesClosure
 
 open class KotlinJvmVariant(containingModule: KotlinGradleModule, fragmentName: String) :
     KotlinGradlePublishedVariantWithRuntime(containingModule, fragmentName) {
@@ -29,48 +21,6 @@ open class KotlinJvmVariant(containingModule: KotlinGradleModule, fragmentName:
 class KotlinJvmVariantCompilationData(val variant: KotlinJvmVariant) : KotlinVariantCompilationDataInternal<KotlinJvmOptions> {
     override val owner: KotlinJvmVariant get() = variant
 
-    override val compilationPurpose: String
-        get() = variant.containingModule.name
-
-    override val compilationClassifier: String
-        get() = variant.name
-
-    override val kotlinSourceDirectoriesByFragmentName: Map<String, SourceDirectorySet>
-        get() = variant.refinesClosure.filterIsInstance<KotlinGradleVariant>().associate { it.disambiguateName("") to it.kotlinSourceRoots }
-
-    override val output: KotlinCompilationOutput
-        get() = variant.compilationOutputs
-
-    override val compileKotlinTaskName: String
-        get() = lowerCamelCaseName("compile", compilationPurpose.takeIf { it != "main" }, "Kotlin", compilationClassifier)
-
-    override val compileAllTaskName: String
-        get() = variant.disambiguateName("classes")
-
-    override val compileDependencyFiles: FileCollection
-        get() = variant.compileDependencyFiles
-
-    override val languageSettings: LanguageSettingsBuilder
-        get() = variant.languageSettings
-
-    override val platformType: KotlinPlatformType
-        get() = variant.platformType
-
-    override val friendPaths: Iterable<FileCollection>
-        // TODO for now, all output classes of the module are considered friends, even those not on the classpath
-        get() {
-            // FIXME support compiling against the JARs
-            return variant.containingModule.project.pm20Extension.modules.flatMap { it.variants.map { it.compilationOutputs.classesDirs } }
-        }
-
-    override val moduleName: String
-        get() = // TODO accurate module names that don't rely on all variants having a main counterpart
-            variant.containingModule.project.pm20Extension.modules
-                .getByName(KotlinGradleModule.MAIN_MODULE_NAME).variants.findByName(variant.name)?.ownModuleName() ?: ownModuleName
-
-    override val ownModuleName: String
-        get() = variant.ownModuleName()
-
     // TODO pull out to the variant
     override val kotlinOptions: KotlinJvmOptions
         get() = KotlinJvmOptionsImpl()

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/KotlinMetadataCompilationData.kt

@@ -0,0 +1,206 @@
+/*
+ * 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.gradle.plugin.mpp.pm20
+
+import org.gradle.api.DefaultTask
+import org.gradle.api.Project
+import org.gradle.api.file.FileCollection
+import org.gradle.api.file.SourceDirectorySet
+import org.gradle.api.plugins.BasePluginConvention
+import org.gradle.api.tasks.TaskProvider
+import org.jetbrains.kotlin.gradle.dsl.KotlinCommonOptions
+import org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformCommonOptions
+import org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformCommonOptionsImpl
+import org.jetbrains.kotlin.gradle.dsl.pm20Extension
+import org.jetbrains.kotlin.gradle.plugin.*
+import org.jetbrains.kotlin.gradle.plugin.mpp.*
+import org.jetbrains.kotlin.gradle.plugin.sources.DefaultLanguageSettingsBuilder
+import org.jetbrains.kotlin.gradle.targets.metadata.ResolvedMetadataFilesProvider
+import org.jetbrains.kotlin.gradle.targets.metadata.createTransformedMetadataClasspath
+import org.jetbrains.kotlin.gradle.utils.getValue
+import org.jetbrains.kotlin.gradle.utils.lowerCamelCaseName
+import org.jetbrains.kotlin.konan.target.HostManager
+import org.jetbrains.kotlin.konan.target.KonanTarget
+
+interface KotlinMetadataCompilationData<T : KotlinCommonOptions> : KotlinCompilationData<T> {
+    val isActive: Boolean
+}
+
+interface KotlinCommonFragmentMetadataCompilationData : KotlinMetadataCompilationData<KotlinMultiplatformCommonOptions>
+
+internal abstract class AbstractKotlinFragmentMetadataCompilationData<T : KotlinCommonOptions>(
+    final override val project: Project,
+    val fragment: KotlinGradleFragment,
+    private val module: KotlinGradleModule,
+    private val compileAllTask: TaskProvider<DefaultTask>,
+    val metadataCompilationRegistry: MetadataCompilationRegistry,
+    private val resolvedMetadataFiles: Lazy<Iterable<ResolvedMetadataFilesProvider>>
+) : KotlinMetadataCompilationData<T> {
+
+    override val owner
+        get() = project.pm20Extension
+
+    override val compilationPurpose: String
+        get() = fragment.fragmentName
+
+    override val compilationClassifier: String
+        get() = lowerCamelCaseName(module.name, "metadata")
+
+    override val kotlinSourceDirectoriesByFragmentName: Map<String, SourceDirectorySet>
+        get() = mapOf(fragment.fragmentName to fragment.kotlinSourceRoots)
+
+    override val compileKotlinTaskName: String
+        get() = lowerCamelCaseName("compile", fragment.disambiguateName(""), "KotlinMetadata")
+
+    override val compileAllTaskName: String
+        get() = compileAllTask.name
+
+    override val compileDependencyFiles: FileCollection by project.provider {
+        createTransformedMetadataClasspath(
+            project,
+            resolvableMetadataConfiguration(fragment.containingModule),
+            lazy { fragment.refinesClosure.minus(fragment).map { metadataCompilationRegistry.byFragment(it).output.classesDirs } },
+            resolvedMetadataFiles
+        )
+    }
+
+    override val output: KotlinCompilationOutput = DefaultKotlinCompilationOutput(
+        project,
+        project.provider { project.buildDir.resolve("processedResources/${fragment.disambiguateName("metadata")}") }
+    )
+
+    override val languageSettings: LanguageSettingsBuilder = DefaultLanguageSettingsBuilder() // FIXME apply settings
+
+    override val platformType: KotlinPlatformType
+        get() = KotlinPlatformType.common
+
+    override val moduleName: String
+        get() { // FIXME deduplicate with ownModuleName
+            val baseName = project.convention.findPlugin(BasePluginConvention::class.java)?.archivesBaseName
+                ?: project.name
+            val suffix = if (module.moduleClassifier == null) "" else "_${module.moduleClassifier}"
+            return filterModuleName("$baseName$suffix")
+        }
+
+    override val ownModuleName: String
+        get() = moduleName
+
+    override val friendPaths: Iterable<FileCollection>
+        get() = metadataCompilationRegistry.run {
+            fragment.refinesClosure.minus(fragment)
+                .map {
+                    metadataCompilationRegistry.byFragment(it).output.classesDirs
+                }
+        }
+}
+
+internal open class KotlinCommonFragmentMetadataCompilationDataImpl(
+    project: Project,
+    fragment: KotlinGradleFragment,
+    module: KotlinGradleModule,
+    compileAllTask: TaskProvider<DefaultTask>,
+    metadataCompilationRegistry: MetadataCompilationRegistry,
+    resolvedMetadataFiles: Lazy<Iterable<ResolvedMetadataFilesProvider>>
+) : AbstractKotlinFragmentMetadataCompilationData<KotlinMultiplatformCommonOptions>(
+    project,
+    fragment,
+    module,
+    compileAllTask,
+    metadataCompilationRegistry,
+    resolvedMetadataFiles), KotlinCommonFragmentMetadataCompilationData {
+
+    override val isActive: Boolean
+        get() = !fragment.isNativeShared()
+
+    override val kotlinOptions: KotlinMultiplatformCommonOptions = KotlinMultiplatformCommonOptionsImpl()
+}
+
+interface KotlinNativeFragmentMetadataCompilationData :
+    KotlinMetadataCompilationData<KotlinCommonOptions>,
+    KotlinNativeCompilationData<KotlinCommonOptions>
+
+internal fun KotlinGradleFragment.isNativeShared(): Boolean =
+    containingModule.variantsContainingFragment(this).all { it.platformType == KotlinPlatformType.native }
+
+internal fun KotlinGradleFragment.isNativeHostSpecific(): Boolean =
+    this in getHostSpecificFragments(containingModule)
+
+internal open class KotlinNativeFragmentMetadataCompilationDataImpl(
+    project: Project,
+    fragment: KotlinGradleFragment,
+    module: KotlinGradleModule,
+    compileAllTask: TaskProvider<DefaultTask>,
+    metadataCompilationRegistry: MetadataCompilationRegistry,
+    resolvedMetadataFiles: Lazy<Iterable<ResolvedMetadataFilesProvider>>
+) : AbstractKotlinFragmentMetadataCompilationData<KotlinCommonOptions>(
+    project,
+    fragment,
+    module,
+    compileAllTask,
+    metadataCompilationRegistry,
+    resolvedMetadataFiles
+), KotlinNativeFragmentMetadataCompilationData {
+
+    override val compileKotlinTaskName: String
+        get() = lowerCamelCaseName("compile", fragment.disambiguateName(""), "KotlinNativeMetadata")
+
+    override val isActive: Boolean
+        get() = fragment.isNativeShared()
+
+    override val kotlinOptions: NativeCompileOptions
+        get() = NativeCompileOptions { languageSettings }
+
+    override val konanTarget: KonanTarget
+        get() {
+            val nativeVariants =
+                fragment.containingModule.variantsContainingFragment(fragment).filterIsInstance<KotlinNativeVariantInternal>()
+            return nativeVariants.firstOrNull { it.konanTarget.enabledOnCurrentHost }?.konanTarget
+                ?: nativeVariants.firstOrNull()?.konanTarget
+                ?: HostManager.host
+        }
+
+    // FIXME endorsed libs?
+    override val enableEndorsedLibs: Boolean
+        get() = false
+}
+
+// TODO think about more generic case: a fragment that can be compiled by an arbitrary compiler
+//      what tasks should we create? should there be a generic task for that?
+internal class MetadataCompilationRegistry {
+    private val commonCompilationDataPerFragment = mutableMapOf<KotlinGradleFragment, KotlinCommonFragmentMetadataCompilationDataImpl>()
+    private val nativeCompilationDataPerFragment = mutableMapOf<KotlinGradleFragment, KotlinNativeFragmentMetadataCompilationDataImpl>()
+
+    fun registerCommon(fragment: KotlinGradleFragment, compilationData: KotlinCommonFragmentMetadataCompilationDataImpl) {
+        commonCompilationDataPerFragment.compute(fragment) { _, existing ->
+            existing?.let { error("common compilation data for fragment $fragment already registered") }
+            compilationData
+        }
+        withAllCommonCallbacks.forEach { it.invoke(compilationData) }
+    }
+
+    fun registerNative(fragment: KotlinGradleFragment, compilationData: KotlinNativeFragmentMetadataCompilationDataImpl) {
+        nativeCompilationDataPerFragment.compute(fragment) { _, existing ->
+            existing?.let { error("native compilation data for fragment $fragment already registered") }
+            compilationData
+        }
+        withAllNativeCallbacks.forEach { it.invoke(compilationData) }
+    }
+
+    fun byFragment(fragment: KotlinGradleFragment): KotlinMetadataCompilationData<*> =
+        listOf(commonCompilationDataPerFragment.getValue(fragment), nativeCompilationDataPerFragment.getValue(fragment)).single {
+            it.isActive
+        }
+
+    private val withAllCommonCallbacks = mutableListOf<(AbstractKotlinFragmentMetadataCompilationData<*>) -> Unit>()
+    private val withAllNativeCallbacks = mutableListOf<(AbstractKotlinFragmentMetadataCompilationData<*>) -> Unit>()
+
+    fun withAll(action: (AbstractKotlinFragmentMetadataCompilationData<*>) -> Unit) {
+        commonCompilationDataPerFragment.forEach { action(it.value) }
+        nativeCompilationDataPerFragment.forEach { action(it.value) }
+        withAllCommonCallbacks += action
+        withAllNativeCallbacks += action
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/KotlinNativeVariant.kt

@@ -0,0 +1,77 @@
+/*
+ * 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.gradle.plugin.mpp.pm20
+
+import org.gradle.api.Project
+import org.jetbrains.kotlin.gradle.dsl.KotlinCommonOptions
+import org.jetbrains.kotlin.gradle.plugin.mpp.DefaultCInteropSettings
+import org.jetbrains.kotlin.gradle.plugin.mpp.NativeCompileOptions
+import org.jetbrains.kotlin.gradle.plugin.mpp.publishedConfigurationName
+import org.jetbrains.kotlin.konan.target.KonanTarget
+import javax.inject.Inject
+
+open class KotlinNativeVariantInternal(
+    containingModule: KotlinGradleModule,
+    fragmentName: String,
+    val konanTarget: KonanTarget
+) : KotlinNativeVariant,
+    KotlinGradleVariantInternal(containingModule, fragmentName),
+    SingleMavenPublicationHolder by DefaultSingleMavenPublicationHolder(containingModule, fragmentName) {
+
+    override var enableEndorsedLibraries: Boolean = false
+
+    override val gradleVariantNames: Set<String>
+        get() = listOf(apiElementsConfigurationName).flatMap { listOf(it, publishedConfigurationName(it)) }.toSet()
+
+    val cinterops = project.container(DefaultCInteropSettings::class.java) { cinteropName ->
+        DefaultCInteropSettings(project, cinteropName, compilationData)
+    }
+
+    internal val compilationData by lazy { KotlinNativeVariantCompilationData(this) }
+}
+
+// FIXME codegen
+open class KotlinLinuxX64Variant @Inject constructor(containingModule: KotlinGradleModule, fragmentName: String) :
+    KotlinNativeVariantInternal(containingModule, fragmentName, KonanTarget.LINUX_X64)
+
+open class KotlinMacosX64Variant @Inject constructor(containingModule: KotlinGradleModule, fragmentName: String) :
+    KotlinNativeVariantInternal(containingModule, fragmentName, KonanTarget.MACOS_X64)
+
+open class KotlinMacosArm64Variant @Inject constructor(containingModule: KotlinGradleModule, fragmentName: String) :
+    KotlinNativeVariantInternal(containingModule, fragmentName, KonanTarget.MACOS_ARM64)
+
+open class KotlinIosX64Variant @Inject constructor(containingModule: KotlinGradleModule, fragmentName: String) :
+    KotlinNativeVariantInternal(containingModule, fragmentName, KonanTarget.IOS_X64)
+
+open class KotlinIosArm64Variant @Inject constructor(containingModule: KotlinGradleModule, fragmentName: String) :
+    KotlinNativeVariantInternal(containingModule, fragmentName, KonanTarget.IOS_ARM64)
+
+
+internal val KotlinNativeVariant.hostSpecificMetadataConfigurationName
+    get() = disambiguateName("MetadataElements")
+
+interface KotlinNativeCompilationData<T : KotlinCommonOptions> : KotlinCompilationData<T> {
+    val konanTarget: KonanTarget
+    val enableEndorsedLibs: Boolean
+}
+
+internal class KotlinNativeVariantCompilationData(
+    val variant: KotlinNativeVariantInternal
+) : KotlinVariantCompilationDataInternal<KotlinCommonOptions>, KotlinNativeCompilationData<KotlinCommonOptions> {
+    override val konanTarget: KonanTarget
+        get() = variant.konanTarget
+
+    override val enableEndorsedLibs: Boolean
+        get() = variant.enableEndorsedLibraries
+
+    override val project: Project
+        get() = variant.containingModule.project
+
+    override val owner: KotlinNativeVariant
+        get() = variant
+
+    override val kotlinOptions: KotlinCommonOptions = NativeCompileOptions { languageSettings }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/KotlinNativeVariantFactory.kt

@@ -30,6 +30,7 @@ import org.jetbrains.kotlin.gradle.utils.dashSeparatedName
 import org.jetbrains.kotlin.library.KLIB_FILE_EXTENSION
 import org.jetbrains.kotlin.project.model.refinesClosure
 import org.jetbrains.kotlin.project.model.utils.variantsContainingFragment
+import java.util.concurrent.Callable
 import kotlin.reflect.KClass
 
 open class KotlinNativeVariantFactory<T : KotlinNativeVariantInternal>(

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/abstractVariantFactories.kt

@@ -27,12 +27,13 @@ abstract class AbstractKotlinGradleVariantFactory<T : KotlinGradleVariant>(
     module: KotlinGradleModule
 ) : AbstractKotlinGradleFragmentFactory<T>(module) {
 
-    override fun create(name: String): T = super.create(name).also { fragment ->
+    override fun create(name: String): T =
-        createSourcesArchiveTask(fragment)
+        super.create(name).also { fragment ->
-        configureKotlinCompilation(fragment)
+            createSourcesArchiveTask(fragment)
-        createElementsConfigurations(fragment)
+            createElementsConfigurations(fragment)
-        // TODO configure resources processing
+            configureKotlinCompilation(fragment)
-    }
+            // TODO configure resources processing
+        }
 
     protected open fun setPlatformAttributesInConfiguration(fragment: T, configuration: Configuration) {
         configuration.attributes.attribute(KotlinPlatformType.attribute, fragment.platformType)

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/abstractVariants.kt

@@ -57,6 +57,9 @@ abstract class KotlinGradleVariantInternal(
     override fun toString(): String = "variant $fragmentName in $containingModule"
 }
 
+internal val KotlinGradleVariant.compileDependencyConfiguration: Configuration
+    get() = containingModule.project.configurations.getByName(compileDependencyConfigurationName)
+
 class DefaultSingleMavenPublicationHolder(
     private var module: KotlinGradleModule,
     override val defaultPublishedModuleSuffix: String?

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/fragmentFactories.kt

@@ -32,7 +32,7 @@ abstract class AbstractKotlinGradleFragmentFactory<T : KotlinGradleFragment>(
         with(project.configurations) {
             fragment.relatedConfigurationNames.forEach { configurationName ->
                 maybeCreate(configurationName).apply {
-                    // FIXME add metadata configurations?
+                    // FIXME add metadata configurations or API for IDE import?
                     if (!configurationName.endsWith(METADATA_CONFIGURATION_NAME_SUFFIX)) {
                         isCanBeResolved = false
                     }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/fragmentsMetadataCompilation.kt

@@ -10,7 +10,6 @@ import org.gradle.api.Project
 import org.gradle.api.attributes.Usage
 import org.gradle.api.tasks.TaskProvider
 import org.gradle.jvm.tasks.Jar
-import org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformCommonOptions
 import org.jetbrains.kotlin.gradle.dsl.pm20Extension
 import org.jetbrains.kotlin.gradle.plugin.*
 import org.jetbrains.kotlin.gradle.plugin.KotlinCommonSourceSetProcessor
@@ -23,6 +22,7 @@ import org.jetbrains.kotlin.gradle.tasks.registerTask
 import org.jetbrains.kotlin.gradle.tasks.withType
 import org.jetbrains.kotlin.gradle.utils.addExtendsFromRelation
 import org.jetbrains.kotlin.gradle.utils.lowerCamelCaseName
+import org.jetbrains.kotlin.library.KLIB_FILE_EXTENSION
 import org.jetbrains.kotlin.project.model.KotlinModuleFragment
 import java.util.concurrent.Callable
 
@@ -66,7 +66,7 @@ private fun generateAndExportProjectStructureMetadata(
     module: KotlinGradleModule
 ) {
     val project = module.project
-    val projectStructureMetadata = project.createGenerateProjectStructureMetadataTask(module.moduleClassifier)
+    val projectStructureMetadata = project.createGenerateProjectStructureMetadataTask(module)
     project.tasks.withType<Jar>().named(metadataJarName(module)).configure { jar ->
         jar.from(projectStructureMetadata.map { it.resultFile }) { spec ->
             spec.into("META-INF")
@@ -74,7 +74,7 @@ private fun generateAndExportProjectStructureMetadata(
         }
     }
     GlobalProjectStructureMetadataStorage.registerProjectStructureMetadata(project) {
-        checkNotNull(buildKotlinProjectStructureMetadata(project))
+        buildProjectStructureMetadata(module)
     }
 }
 
@@ -108,7 +108,13 @@ private fun configureMetadataCompilationsAndCreateRegistry(
     }
     val compileAllTask = project.registerTask<DefaultTask>(lowerCamelCaseName(module.moduleClassifier, "metadataClasses"))
     module.fragments.all { fragment ->
-        createMetadataCompilation(fragment, compileAllTask, metadataCompilationRegistry)
+        createCommonMetadataCompilation(fragment, compileAllTask, metadataCompilationRegistry)
+        createNativeMetadataCompilation(fragment, compileAllTask, metadataCompilationRegistry)
+    }
+    metadataCompilationRegistry.withAll { compilation ->
+        project.tasks.matching { it.name == compilation.compileKotlinTaskName }.configureEach { task ->
+            task.onlyIf { compilation.isActive }
+        }
     }
 }
 
@@ -140,49 +146,83 @@ private fun configureMetadataJarTask(
 internal fun metadataJarName(module: KotlinGradleModule) =
     lowerCamelCaseName(module.moduleClassifier, "metadataJar")
 
-private fun createMetadataCompilation(
+private fun createCommonMetadataCompilation(
     fragment: KotlinGradleFragment,
     compileAllTask: TaskProvider<DefaultTask>,
     metadataCompilationRegistry: MetadataCompilationRegistry
-): KotlinCompilationData<out KotlinMultiplatformCommonOptions> {
+) {
     val module = fragment.containingModule
     val project = module.project
 
     val metadataCompilationData =
-        KotlinFragmentMetadataCompilationData(
+        KotlinCommonFragmentMetadataCompilationDataImpl(
             project,
             fragment,
             module,
             compileAllTask,
             metadataCompilationRegistry,
-            lazy {
+            lazy { resolvedMetadataProviders(fragment) }
-                fragment.refinesClosure.map {
-                    FragmentResolvedMetadataProvider(
-                        project.tasks.withType<TransformKotlinGranularMetadataForFragment>()
-                            .named(transformFragmentMetadataTaskName(it))
-                    )
-                }
-            }
         )
-    metadataCompilationRegistry.register(fragment, metadataCompilationData)
-
-    addSourcesToKotlinCompileTask(
-        project,
-        metadataCompilationData.compileKotlinTaskName,
-        /*FIXME*/ emptyList(),
-        { fragment.kotlinSourceRoots },
-        lazyOf(true)
-    )
-
     KotlinCommonSourceSetProcessor(
         metadataCompilationData,
         KotlinTasksProvider(),
         project.getKotlinPluginVersion() ?: "undefined"
     ).run()
-
+    addSourcesToMetadataCompileTask(metadataCompilationData)
-    return metadataCompilationData
+    metadataCompilationRegistry.registerCommon(fragment, metadataCompilationData)
 }
 
+private fun createNativeMetadataCompilation(
+    fragment: KotlinGradleFragment,
+    compileAllTask: TaskProvider<DefaultTask>,
+    metadataCompilationRegistry: MetadataCompilationRegistry
+) {
+    val module = fragment.containingModule
+    val project = module.project
+
+    val metadataCompilationData =
+        KotlinNativeFragmentMetadataCompilationDataImpl(
+            project,
+            fragment,
+            module,
+            compileAllTask,
+            metadataCompilationRegistry,
+            lazy { resolvedMetadataProviders(fragment) }
+        )
+    NativeSharedCompilationProcessor(metadataCompilationData).run()
+    addSourcesToMetadataCompileTask(metadataCompilationData)
+    metadataCompilationRegistry.registerNative(fragment, metadataCompilationData)
+}
+
+private fun addSourcesToMetadataCompileTask(compilationData: AbstractKotlinFragmentMetadataCompilationData<*>) {
+    val sources = { compilationData.fragment.kotlinSourceRoots }
+    when (compilationData) {
+        // Note: this call is invalid for compilations that use Kotlin/Native compile tasks!
+        is KotlinCommonFragmentMetadataCompilationData -> addSourcesToKotlinCompileTask(
+            compilationData.project,
+            compilationData.compileKotlinTaskName,
+            /*FIXME*/ emptyList(),
+            sources,
+            lazyOf(true)
+        )
+        is KotlinNativeFragmentMetadataCompilationData -> addSourcesToKotlinNativeCompileTask(
+            compilationData.project,
+            compilationData.compileKotlinTaskName,
+            sources,
+            lazyOf(true)
+        )
+        else -> error("unexpected compilation data $compilationData")
+    }
+}
+
+private fun resolvedMetadataProviders(fragment: KotlinGradleFragment) =
+    fragment.refinesClosure.map {
+        FragmentResolvedMetadataProvider(
+            fragment.project.tasks.withType<TransformKotlinGranularMetadataForFragment>()
+                .named(transformFragmentMetadataTaskName(it))
+        )
+    }
+
 private fun createExtractMetadataTask(
     project: Project,
     fragment: KotlinGradleFragment,
@@ -206,7 +246,7 @@ private fun createExtractMetadataTask(
 
 // FIXME: use this function once more than one platform is supported
 private fun disableMetadataCompilationIfNotYetSupported(
-    metadataCompilationData: KotlinFragmentMetadataCompilationData
+    metadataCompilationData: AbstractKotlinFragmentMetadataCompilationData<*>
 ) {
     val fragment = metadataCompilationData.fragment
     val platforms = fragment.containingModule.variantsContainingFragment(fragment).map { it.platformType }.toSet()

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/variantPublishing.kt

@@ -0,0 +1,12 @@
+/*
+ * 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.gradle.plugin.mpp.pm20
+
+fun <T> publishVariantWithSinglePublication(
+    variant: T
+) where T : SingleMavenPublicationHolder, T : KotlinGradleVariant {
+
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/metadata/KotlinMetadataTargetConfigurator.kt

@@ -21,6 +21,8 @@ import org.jetbrains.kotlin.gradle.dsl.multiplatformExtension
 import org.jetbrains.kotlin.gradle.plugin.*
 import org.jetbrains.kotlin.gradle.plugin.mpp.*
 import org.jetbrains.kotlin.gradle.plugin.mpp.CompilationSourceSetUtil.compilationsBySourceSets
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinGradleModule
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinNativeFragmentMetadataCompilationData
 import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinPm20ProjectExtension
 import org.jetbrains.kotlin.gradle.plugin.sources.*
 import org.jetbrains.kotlin.gradle.plugin.statistics.KotlinBuildStatsService
@@ -119,20 +121,6 @@ class KotlinMetadataTargetConfigurator(kotlinPluginVersion: String) :
         else -> error("unsupported compilation type ${compilation::class.qualifiedName}")
     }
 
-    private inner class NativeSharedCompilationProcessor(
-        override val kotlinCompilation: KotlinSharedNativeCompilation
-    ) : KotlinCompilationProcessor<KotlinNativeCompile>(kotlinCompilation) {
-
-        private val nativeTargetConfigurator = KotlinNativeTargetConfigurator<KotlinNativeTarget>(kotlinPluginVersion)
-
-        override val kotlinTask: TaskProvider<out KotlinNativeCompile> =
-            with(nativeTargetConfigurator) {
-                project.createKlibCompilationTask(kotlinCompilation)
-            }
-
-        override fun run() = Unit
-    }
-
     override fun createArchiveTasks(target: KotlinMetadataTarget): TaskProvider<out Zip> {
         if (!target.project.isKotlinGranularMetadataEnabled)
             return super.createArchiveTasks(target)
@@ -486,8 +474,28 @@ class KotlinMetadataTargetConfigurator(kotlinPluginVersion: String) :
     }
 }
 
-internal fun Project.createGenerateProjectStructureMetadataTask(moduleClassifier: String? = null): TaskProvider<GenerateProjectStructureMetadata> =
+internal class NativeSharedCompilationProcessor(
-    project.registerTask(lowerCamelCaseName("generate", moduleClassifier, "ProjectStructureMetadata")) { task ->
+    override val kotlinCompilation: KotlinNativeFragmentMetadataCompilationData
+) : KotlinCompilationProcessor<KotlinNativeCompile>(kotlinCompilation) {
+
+    private val nativeTargetConfigurator =
+        KotlinNativeTargetConfigurator<KotlinNativeTarget>(kotlinCompilation.project.getKotlinPluginVersion() ?: "" /*FIXME*/)
+
+    override val kotlinTask: TaskProvider<out KotlinNativeCompile> =
+        with(nativeTargetConfigurator) {
+            project.createKlibCompilationTask(kotlinCompilation)
+        }
+
+    override fun run() = Unit
+}
+
+internal fun Project.createGenerateProjectStructureMetadataTask(module: KotlinGradleModule): TaskProvider<GenerateProjectStructureMetadata> =
+    project.registerTask(lowerCamelCaseName("generate", module.moduleClassifier, "ProjectStructureMetadata")) { task ->
+        task.lazyKotlinProjectStructureMetadata = lazy { buildProjectStructureMetadata(module) }
+    }
+
+internal fun Project.createGenerateProjectStructureMetadataTask(): TaskProvider<GenerateProjectStructureMetadata> =
+    project.registerTask(lowerCamelCaseName("generateProjectStructureMetadata")) { task ->
         task.lazyKotlinProjectStructureMetadata = lazy { checkNotNull(buildKotlinProjectStructureMetadata(project)) }
     }
 

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/native/DefaultCInteropSettings.kt

@@ -15,6 +15,10 @@ import org.gradle.api.provider.Property
 import org.gradle.util.ConfigureUtil
 import org.jetbrains.kotlin.gradle.plugin.CInteropSettings
 import org.jetbrains.kotlin.gradle.plugin.CInteropSettings.IncludeDirectories
+import org.jetbrains.kotlin.gradle.plugin.KotlinCompilation
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinNativeCompilationData
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinNativeVariantCompilationData
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.disambiguateName
 import org.jetbrains.kotlin.gradle.targets.native.internal.CInteropIdentifier
 import org.jetbrains.kotlin.gradle.utils.lowerCamelCaseName
 import java.io.File
@@ -23,7 +27,7 @@ import javax.inject.Inject
 open class DefaultCInteropSettings @Inject constructor(
     private val project: Project,
     private val name: String,
-    override val compilation: KotlinNativeCompilation
+    override val compilation: KotlinNativeCompilationData<*>
 ) : CInteropSettings {
 
     inner class DefaultIncludeDirectories : CInteropSettings.IncludeDirectories {
@@ -46,8 +50,8 @@ open class DefaultCInteropSettings @Inject constructor(
     internal val identifier: CInteropIdentifier
         get() = CInteropIdentifier(CInteropIdentifier.Scope.create(compilation), name)
 
-    val target: KotlinNativeTarget
+    val target: KotlinNativeTarget?
-        get() = compilation.target
+        get() = (compilation as? KotlinNativeCompilation?)?.target
 
     override val dependencyConfigurationName: String
         get() = compilation.disambiguateName("${name.capitalize()}CInterop")
@@ -59,7 +63,7 @@ open class DefaultCInteropSettings @Inject constructor(
             "cinterop",
             compilation.compilationPurpose.takeIf { it != "main" }.orEmpty(),
             name,
-            target.disambiguationClassifier
+            target?.disambiguationClassifier ?: compilation.compilationClassifier
         )
 
     val defFileProperty: Property<File> = project.objects.property(File::class.java)
@@ -129,3 +133,13 @@ open class DefaultCInteropSettings @Inject constructor(
         _extraOptsProp.addAll(project.provider { values.map { it.toString() } })
     }
 }
+
+private fun KotlinNativeCompilationData<*>.disambiguateName(simpleName: String): String = when (this) {
+    is AbstractKotlinNativeCompilation -> (this as AbstractKotlinCompilation<*>).disambiguateName(simpleName)
+    is KotlinNativeVariantCompilationData -> owner.disambiguateName(simpleName)
+    else -> lowerCamelCaseName(
+        this.compilationClassifier,
+        this.compilationPurpose.takeIf { it != KotlinCompilation.MAIN_COMPILATION_NAME },
+        simpleName
+    )
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/native/KotlinNativeCompilation.kt

@@ -9,49 +9,58 @@ package org.jetbrains.kotlin.gradle.plugin.mpp
 import groovy.lang.Closure
 import org.gradle.api.Action
 import org.gradle.api.NamedDomainObjectContainer
+import org.gradle.api.Project
 import org.gradle.api.file.FileCollection
 import org.gradle.api.tasks.TaskProvider
 import org.gradle.util.ConfigureUtil
 import org.jetbrains.kotlin.gradle.dsl.KotlinCommonOptions
 import org.jetbrains.kotlin.gradle.plugin.*
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinNativeCompilationData
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinNativeFragmentMetadataCompilationData
 import org.jetbrains.kotlin.gradle.plugin.sources.getVisibleSourceSetsFromAssociateCompilations
 import org.jetbrains.kotlin.gradle.plugin.sources.resolveAllDependsOnSourceSets
 import org.jetbrains.kotlin.gradle.targets.metadata.getMetadataCompilationForSourceSet
+import org.jetbrains.kotlin.gradle.tasks.AbstractKotlinNativeCompile
 import org.jetbrains.kotlin.gradle.tasks.KotlinNativeCompile
 import org.jetbrains.kotlin.gradle.utils.lowerCamelCaseName
 import org.jetbrains.kotlin.konan.target.KonanTarget
+import java.io.File
 import java.util.concurrent.Callable
 
+internal class NativeCompileOptions(languageSettingsProvider: () -> LanguageSettingsBuilder) : KotlinCommonOptions {
+    private val languageSettings: LanguageSettingsBuilder by lazy(languageSettingsProvider)
+
+    override var apiVersion: String?
+        get() = languageSettings.apiVersion
+        set(value) {
+            languageSettings.apiVersion = value
+        }
+
+    override var languageVersion: String?
+        get() = languageSettings.languageVersion
+        set(value) {
+            languageSettings.languageVersion = value
+        }
+
+    override var useFir: Boolean
+        get() = false
+        set(@Suppress("UNUSED_PARAMETER") value) {}
+
+    override var allWarningsAsErrors: Boolean = false
+    override var suppressWarnings: Boolean = false
+    override var verbose: Boolean = false
+
+    override var freeCompilerArgs: List<String> = listOf()
+}
+
 abstract class AbstractKotlinNativeCompilation(
     target: KotlinTarget,
-    val konanTarget: KonanTarget,
+    override val konanTarget: KonanTarget,
     compilationName: String
-) : AbstractKotlinCompilation<KotlinCommonOptions>(target, compilationName) {
+) : AbstractKotlinCompilation<KotlinCommonOptions>(target, compilationName), KotlinNativeCompilationData<KotlinCommonOptions> {
 
     override val kotlinOptions: KotlinCommonOptions = NativeCompileOptions { defaultSourceSet.languageSettings }
 
-    private class NativeCompileOptions(languageSettingsProvider: () -> LanguageSettingsBuilder) : KotlinCommonOptions {
-        private val languageSettings: LanguageSettingsBuilder by lazy(languageSettingsProvider)
-
-        override var apiVersion: String?
-            get() = languageSettings.apiVersion
-            set(value) { languageSettings.apiVersion = value }
-
-        override var languageVersion: String?
-            get() = languageSettings.languageVersion
-            set(value) { languageSettings.languageVersion = value }
-
-        override var useFir: Boolean
-            get() = false
-            set(@Suppress("UNUSED_PARAMETER") value) {}
-
-        override var allWarningsAsErrors: Boolean = false
-        override var suppressWarnings: Boolean = false
-        override var verbose: Boolean = false
-
-        override var freeCompilerArgs: List<String> = listOf()
-    }
-
     override val compileKotlinTask: KotlinNativeCompile
         get() = super.compileKotlinTask as KotlinNativeCompile
 
@@ -59,14 +68,25 @@ abstract class AbstractKotlinNativeCompilation(
     override val compileKotlinTaskProvider: TaskProvider<out KotlinNativeCompile>
         get() = super.compileKotlinTaskProvider as TaskProvider<out KotlinNativeCompile>
 
-    override fun addSourcesToCompileTask(sourceSet: KotlinSourceSet, addAsCommonSources: Lazy<Boolean>) =
+    override fun addSourcesToCompileTask(sourceSet: KotlinSourceSet, addAsCommonSources: Lazy<Boolean>) {
-        compileKotlinTaskProvider.configure { task ->
+        addSourcesToKotlinNativeCompileTask(project, compileKotlinTaskName, { sourceSet.kotlin }, addAsCommonSources)
-            task.source(sourceSet.kotlin)
+    }
-            task.commonSources.from(target.project.files(Callable { if (addAsCommonSources.value) sourceSet.kotlin else emptyList<Any>() }))
-        }
 
     // Endorsed library controller.
-    var enableEndorsedLibs: Boolean = false
+    override var enableEndorsedLibs: Boolean = false
+}
+
+internal fun addSourcesToKotlinNativeCompileTask(
+    project: Project,
+    taskName: String,
+    sourceFiles: () -> Iterable<File>,
+    addAsCommonSources: Lazy<Boolean>
+) {
+    project.tasks.withType(KotlinNativeCompile::class.java).matching { it.name == taskName }.configureEach { task ->
+        task.source(sourceFiles)
+        task.commonSources.from(project.files(Callable { if (addAsCommonSources.value) sourceFiles() else emptyList() }))
+    }
+
 }
 
 class KotlinNativeCompilation(
@@ -117,6 +137,7 @@ class KotlinNativeCompilation(
 }
 
 class KotlinSharedNativeCompilation(override val target: KotlinMetadataTarget, val konanTargets: List<KonanTarget>, name: String) :
+    KotlinNativeFragmentMetadataCompilationData,
     AbstractKotlinNativeCompilation(
         target,
         // TODO: this will end up as '-target' argument passed to K2Native, which is wrong.
@@ -137,4 +158,7 @@ class KotlinSharedNativeCompilation(override val target: KotlinMetadataTarget, v
             }
             project.files(friendSourceSets.mapNotNull { project.getMetadataCompilationForSourceSet(it)?.output?.classesDirs })
         })
+
+    override val isActive: Boolean
+        get() = true // old plugin only creates necessary compilations
 }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/native/KotlinNativeTarget.kt

@@ -10,13 +10,14 @@ import org.gradle.api.NamedDomainObjectContainer
 import org.gradle.api.Project
 import org.gradle.api.artifacts.Dependency
 import org.gradle.api.attributes.Attribute
-import org.gradle.api.attributes.Usage
 import org.gradle.jvm.tasks.Jar
 import org.gradle.util.WrapUtil
 import org.jetbrains.kotlin.gradle.dsl.KotlinNativeBinaryContainer
 import org.jetbrains.kotlin.gradle.dsl.kotlinExtension
-import org.jetbrains.kotlin.gradle.dsl.multiplatformExtension
 import org.jetbrains.kotlin.gradle.plugin.*
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.*
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.isNativeShared
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.variantsContainingFragment
 import org.jetbrains.kotlin.gradle.targets.metadata.*
 import org.jetbrains.kotlin.gradle.targets.metadata.filesWithUnpackedArchives
 import org.jetbrains.kotlin.gradle.targets.metadata.isKotlinGranularMetadataEnabled
@@ -136,26 +137,49 @@ open class KotlinNativeTarget @Inject constructor(
     }
 }
 
-internal fun getHostSpecificSourceSets(project: Project): List<KotlinSourceSet> {
+private val hostManager by lazy { HostManager() }
-    val compilationsBySourceSet = CompilationSourceSetUtil.compilationsBySourceSets(project)
 
-    val enabledByHost = HostManager().enabledByHost
+private fun isHostSpecificKonanTargetsSet(konanTargets: Iterable<KonanTarget>): Boolean {
+    val enabledByHost = hostManager.enabledByHost
     val allHosts = enabledByHost.keys
-
     fun canBeBuiltOnHosts(konanTarget: KonanTarget) = enabledByHost.filterValues { konanTarget in it }.keys
+    return konanTargets.flatMapTo(mutableSetOf(), ::canBeBuiltOnHosts) != allHosts
+}
 
-    return project.kotlinExtension.sourceSets.filter { sourceSet ->
+private fun <T> getHostSpecificElements(
-        if (sourceSet !in compilationsBySourceSet) return@filter false
+    fragments: Iterable<T>,
+    isNativeShared: (T) -> Boolean,
+    getKonanTargets: (T) -> Set<KonanTarget>
+): Set<T> = fragments.filterTo(mutableSetOf()) { isNativeShared(it) && isHostSpecificKonanTargetsSet(getKonanTargets(it)) }
 
-        // If the source set participates in compilations such that some host can't run either of them, then on that host,
+internal fun getHostSpecificFragments(
-        // we can't analyze the source set, so the source set's metadata can't be published from that host, and therefore
+    module: KotlinGradleModule
-        // we consider it platform-specific and publish as a part of the Native targets where the source set takes part,
+): Set<KotlinGradleFragment> = getHostSpecificElements<KotlinGradleFragment>(
-        // not the common metadata artifact;
+    module.fragments,
-        val platformCompilations = compilationsBySourceSet.getValue(sourceSet).filter { it !is KotlinMetadataCompilation }
+    isNativeShared = { it.isNativeShared() },
-        val nativeCompilations = platformCompilations.filterIsInstance<KotlinNativeCompilation>()
+    getKonanTargets = {
-        val nativeEnabledOn = nativeCompilations.flatMapTo(mutableSetOf()) { compilation -> canBeBuiltOnHosts(compilation.konanTarget) }
+        val nativeVariants = module.variantsContainingFragment(it).filterIsInstance<KotlinNativeVariantInternal>()
-        platformCompilations == nativeCompilations && allHosts != nativeEnabledOn
+        nativeVariants.mapTo(mutableSetOf()) { it.konanTarget }
     }
+)
+
+internal fun getHostSpecificSourceSets(project: Project): Set<KotlinSourceSet> {
+    val compilationsBySourceSet = CompilationSourceSetUtil.compilationsBySourceSets(project).mapValues { (_, compilations) ->
+        compilations.filter { it !is KotlinMetadataCompilation<*> }
+    }
+
+    return getHostSpecificElements(
+        project.kotlinExtension.sourceSets,
+        isNativeShared = { sourceSet ->
+            val compilations = compilationsBySourceSet[sourceSet].orEmpty()
+            compilations.isNotEmpty() && compilations.all { it.platformType == KotlinPlatformType.native }
+        },
+        getKonanTargets = { sourceSet ->
+            compilationsBySourceSet[sourceSet].orEmpty()
+                .filterIsInstance<KotlinNativeCompilation>()
+                .mapTo(mutableSetOf()) { it.konanTarget }
+        }
+    )
 }
 
 abstract class KotlinNativeTargetWithTests<T : KotlinNativeBinaryTestRun>(

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/native/KotlinNativeTargetConfigurator.kt

@@ -7,6 +7,7 @@
 package org.jetbrains.kotlin.gradle.plugin
 
 import org.gradle.api.DefaultTask
+import org.gradle.api.NamedDomainObjectCollection
 import org.gradle.api.Project
 import org.gradle.api.Task
 import org.gradle.api.artifacts.Configuration
@@ -29,6 +30,7 @@ import org.jetbrains.kotlin.gradle.plugin.KotlinCompilation.Companion.TEST_COMPI
 import org.jetbrains.kotlin.gradle.plugin.PropertiesProvider.Companion.KOTLIN_NATIVE_IGNORE_INCORRECT_DEPENDENCIES
 import org.jetbrains.kotlin.gradle.plugin.mpp.*
 import org.jetbrains.kotlin.gradle.plugin.mpp.apple.registerAssembleAppleFrameworkTask
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.*
 import org.jetbrains.kotlin.gradle.targets.metadata.isKotlinGranularMetadataEnabled
 import org.jetbrains.kotlin.gradle.targets.native.*
 import org.jetbrains.kotlin.gradle.targets.native.internal.commonizeCInteropTask
@@ -51,10 +53,10 @@ open class KotlinNativeTargetConfigurator<T : KotlinNativeTarget>(
     createTestCompilation = true
 ) {
     private fun Project.klibOutputDirectory(
-        compilation: AbstractKotlinNativeCompilation
+        compilation: KotlinCompilationData<*>
     ): File {
-        val targetSubDirectory = compilation.target.disambiguationClassifier?.let { "$it/" }.orEmpty()
+        val targetSubDirectory = compilation.compilationClassifier?.let { "$it/" }.orEmpty()
-        return buildDir.resolve("classes/kotlin/$targetSubDirectory${compilation.name}")
+        return buildDir.resolve("classes/kotlin/$targetSubDirectory${compilation.compilationPurpose}")
     }
 
     private fun addCompilerPlugins(compilation: AbstractKotlinNativeCompilation) {
@@ -73,9 +75,25 @@ open class KotlinNativeTargetConfigurator<T : KotlinNativeTarget>(
         }
     }
 
-    // region Artifact creation.
+    private val KotlinNativeCompilationData<*>.apiElementsConfigurationName: String
+        get() = when (val dataOwner = owner) {
+            is KotlinGradleVariant -> dataOwner.apiElementsConfigurationName
+            is KotlinTarget -> dataOwner.apiElementsConfigurationName
+            else -> error("unexpected owner of $this")
+        }
+
+    internal fun Project.createRegularKlibArtifact(
+        compilation: KotlinNativeCompilationData<*>,
+        compileTask: TaskProvider<out KotlinNativeCompile>
+    ) = createKlibArtifact(compilation, compileTask.map { it.outputFile.get() }, null, compileTask)
+
+    internal fun Project.createCInteropKlibArtifact(
+        interop: DefaultCInteropSettings,
+        interopTask: TaskProvider<out CInteropProcess>
+    ) = createKlibArtifact(interop.compilation, interopTask.map { it.outputFile }, "cinterop-${interop.name}", interopTask, copy = true)
+
     private fun Project.createKlibArtifact(
-        compilation: KotlinNativeCompilation,
+        compilation: KotlinNativeCompilationData<*>,
         artifactFile: Provider<File>,
         classifier: String?,
         producingTask: TaskProvider<*>,
@@ -85,14 +103,14 @@ open class KotlinNativeTargetConfigurator<T : KotlinNativeTarget>(
             return
         }
 
-        val apiElements = configurations.getByName(compilation.target.apiElementsConfigurationName)
+        val apiElements = configurations.getByName(compilation.apiElementsConfigurationName)
 
         val realProducingTask: TaskProvider<*>
         // TODO: Someone remove this HACK PLEASE!
         val realArtifactFile = if (copy) {
             realProducingTask = project.registerTask<Copy>("copy${producingTask.name.capitalize()}") {
-                val targetSubDirectory = compilation.target.disambiguationClassifier?.let { "$it/" }.orEmpty()
+                val targetSubDirectory = compilation.compilationClassifier?.let { "$it/" }.orEmpty()
-                it.destinationDir = project.buildDir.resolve("libs/$targetSubDirectory${compilation.name}")
+                it.destinationDir = project.buildDir.resolve("libs/$targetSubDirectory${compilation.compilationPurpose}")
                 it.from(artifactFile)
                 it.dependsOn(producingTask)
             }
@@ -104,7 +122,7 @@ open class KotlinNativeTargetConfigurator<T : KotlinNativeTarget>(
 
         with(apiElements) {
             val klibArtifact = project.artifacts.add(apiElements.name, realArtifactFile) { artifact ->
-                artifact.name = compilation.name
+                artifact.name = compilation.compilationPurpose
                 artifact.extension = "klib"
                 artifact.type = "klib"
                 artifact.classifier = classifier
@@ -115,18 +133,6 @@ open class KotlinNativeTargetConfigurator<T : KotlinNativeTarget>(
             attributes.attribute(ArtifactAttributes.ARTIFACT_FORMAT, NativeArtifactFormat.KLIB)
         }
     }
-
-    private fun Project.createRegularKlibArtifact(
-        compilation: KotlinNativeCompilation,
-        compileTask: TaskProvider<out KotlinNativeCompile>
-    ) = createKlibArtifact(compilation, compileTask.map { it.outputFile.get() }, null, compileTask)
-
-    private fun Project.createCInteropKlibArtifact(
-        interop: DefaultCInteropSettings,
-        interopTask: TaskProvider<out CInteropProcess>
-    ) = createKlibArtifact(interop.compilation, interopTask.map { it.outputFile }, "cinterop-${interop.name}", interopTask, copy = true)
-    // endregion.
-
     // region Task creation.
     private fun Project.createLinkTask(binary: NativeBinary) {
         val result = registerTask<KotlinNativeLink>(
@@ -258,12 +264,12 @@ open class KotlinNativeTargetConfigurator<T : KotlinNativeTarget>(
         }
     }
 
-    internal fun Project.createKlibCompilationTask(compilation: AbstractKotlinNativeCompilation): TaskProvider<KotlinNativeCompile> {
+    internal fun Project.createKlibCompilationTask(compilation: KotlinNativeCompilationData<*>): TaskProvider<KotlinNativeCompile> {
         val compileTaskProvider = registerTask<KotlinNativeCompile>(
             compilation.compileKotlinTaskName, listOf(compilation)
         ) {
             it.group = BasePlugin.BUILD_GROUP
-            it.description = "Compiles a klibrary from the '${compilation.name}' " +
+            it.description = "Compiles a klibrary from the '${compilation.compilationPurpose}' " +
                     "compilation for target '${compilation.platformType.name}'."
             it.enabled = compilation.konanTarget.enabledOnCurrentHost
 
@@ -275,33 +281,39 @@ open class KotlinNativeTargetConfigurator<T : KotlinNativeTarget>(
             project.files(compileTaskProvider.map { it.outputFile })
         }
 
-
         project.tasks.getByName(compilation.compileAllTaskName).dependsOn(compileTaskProvider)
 
-        if (compilation.isMain()) {
+        if (compilation.isMainCompilationData()) {
-            compilation as? KotlinNativeCompilation ?: error("Main shared-Native compilation is not yet supported!")
+            if (compilation is KotlinNativeCompilation) {
-
+                project.tasks.getByName(compilation.target.artifactsTaskName).apply {
-            project.tasks.getByName(compilation.target.artifactsTaskName).apply {
+                    dependsOn(compileTaskProvider)
-                dependsOn(compileTaskProvider)
+                }
             }
+
             project.tasks.getByName(LifecycleBasePlugin.ASSEMBLE_TASK_NAME).apply {
                 dependsOn(compileTaskProvider)
             }
             createRegularKlibArtifact(compilation, compileTaskProvider)
         }
-        addCompilerPlugins(compilation)
+        if (compilation is AbstractKotlinNativeCompilation) {
-
+            // FIXME: support compiler plugins for PM20
+            addCompilerPlugins(compilation)
+        }
 
         return compileTaskProvider
     }
 
-    private fun Project.createCInteropTasks(compilation: KotlinNativeCompilation) {
+    // FIXME support creating interop tasks for PM20
-        compilation.cinterops.all { interop ->
+    private fun Project.createCInteropTasks(
+        compilation: KotlinNativeCompilation,
+        cinterops: NamedDomainObjectCollection<DefaultCInteropSettings>
+    ) {
+        cinterops.all { interop ->
             val interopTask = registerTask<CInteropProcess>(interop.interopProcessingTaskName, listOf(interop)) {
                 it.destinationDir = provider { klibOutputDirectory(compilation).resolve("cinterop") }
                 it.group = INTEROP_GROUP
                 it.description = "Generates Kotlin/Native interop library '${interop.name}' " +
-                        "for compilation '${compilation.name}'" +
+                        "for compilation '${compilation.compilationPurpose}'" +
                         "of target '${it.konanTarget.name}'."
                 it.enabled = compilation.konanTarget.enabledOnCurrentHost
             }
@@ -377,7 +389,7 @@ open class KotlinNativeTargetConfigurator<T : KotlinNativeTarget>(
 
     protected fun configureCInterops(target: KotlinNativeTarget): Unit = with(target.project) {
         target.compilations.all { compilation ->
-            createCInteropTasks(compilation)
+            createCInteropTasks(compilation, compilation.cinterops)
             compilation.cinterops.all {
                 defineConfigurationsForCInterop(compilation, it, target, configurations)
             }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/native/internal/CInteropCommonizerTask.kt

@@ -172,7 +172,8 @@ private fun CInteropProcess.toGist(): CInteropGist {
     return CInteropGist(
         identifier = settings.identifier,
         konanTarget = konanTarget,
-        sourceSets = project.provider { settings.compilation.kotlinSourceSetsIncludingDefault },
+        // FIXME support cinterop with PM20
+        sourceSets = project.provider { (settings.compilation as? KotlinCompilation<*>)?.kotlinSourceSetsIncludingDefault },
         libraryFile = outputFileProvider,
 
         /**

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/native/internal/CInteropIdentifier.kt

@@ -6,7 +6,7 @@
 package org.jetbrains.kotlin.gradle.targets.native.internal
 
 import org.gradle.api.tasks.Input
-import org.jetbrains.kotlin.gradle.plugin.KotlinCompilation
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinCompilationData
 import org.jetbrains.kotlin.gradle.utils.UnsafeApi
 import java.io.Serializable
 
@@ -20,7 +20,7 @@ internal data class CInteropIdentifier internal constructor(
     class Scope @UnsafeApi internal constructor(val name: String) : Serializable {
         companion object {
             @OptIn(UnsafeApi::class)
-            fun create(compilation: KotlinCompilation<*>): Scope {
+            fun create(compilation: KotlinCompilationData<*>): Scope {
                 return Scope("compilation/${compilation.compileKotlinTaskName}")
             }
         }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/native/tasks/KotlinNativeTasks.kt

@@ -26,6 +26,9 @@ import org.jetbrains.kotlin.gradle.internal.ensureParentDirsCreated
 import org.jetbrains.kotlin.gradle.plugin.LanguageSettingsBuilder
 import org.jetbrains.kotlin.gradle.plugin.cocoapods.asValidFrameworkName
 import org.jetbrains.kotlin.gradle.plugin.mpp.*
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinNativeCompilationData
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinNativeFragmentMetadataCompilationData
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.isMainCompilationData
 import org.jetbrains.kotlin.gradle.plugin.sources.DefaultLanguageSettingsBuilder
 import org.jetbrains.kotlin.gradle.targets.native.internal.isAllowCommonizer
 import org.jetbrains.kotlin.gradle.utils.getValue
@@ -113,7 +116,7 @@ private fun Collection<File>.filterKlibsPassedToCompiler(project: Project) = fil
 }
 
 // endregion
-abstract class AbstractKotlinNativeCompile<T : KotlinCommonToolOptions, K : AbstractKotlinNativeCompilation> : AbstractCompile() {
+abstract class AbstractKotlinNativeCompile<T : KotlinCommonToolOptions, K : KotlinNativeCompilationData<*>> : AbstractCompile() {
     @get:Internal
     abstract val compilation: K
 
@@ -139,7 +142,7 @@ abstract class AbstractKotlinNativeCompile<T : KotlinCommonToolOptions, K : Abst
     }
 
     private val isSharedCompilation by project.provider {
-        compilation is KotlinSharedNativeCompilation
+        compilation is KotlinNativeFragmentMetadataCompilationData
     }
 
     // Inputs and outputs
@@ -178,7 +181,7 @@ abstract class AbstractKotlinNativeCompile<T : KotlinCommonToolOptions, K : Abst
 
     @get:Internal
     val languageSettings: LanguageSettingsBuilder by project.provider {
-        compilation.defaultSourceSet.languageSettings
+        compilation.languageSettings
     }
 
     @get:Input
@@ -233,7 +236,7 @@ abstract class AbstractKotlinNativeCompile<T : KotlinCommonToolOptions, K : Abst
         get() = buildCommonArgs(true)
 
     private val languageSettingsBuilder by project.provider {
-        compilation.defaultSourceSet.languageSettings
+        compilation.languageSettings
     }
 
     // Args used by both the compiler and IDEA.
@@ -343,8 +346,8 @@ open class KotlinNativeCompile
 constructor(
     @Internal
     @Transient  // can't be serialized for Gradle configuration cache
-    final override val compilation: AbstractKotlinNativeCompilation
+    final override val compilation: KotlinNativeCompilationData<*>
-) : AbstractKotlinNativeCompile<KotlinCommonOptions, AbstractKotlinNativeCompilation>(),
+) : AbstractKotlinNativeCompile<KotlinCommonOptions, KotlinNativeCompilationData<*>>(),
     KotlinCompile<KotlinCommonOptions> {
 
     @get:Input
@@ -357,7 +360,11 @@ constructor(
     override val debuggable = true
 
     @get:Internal
-    override val baseName: String by project.provider { if (compilation.isMain()) project.name else "${project.name}_${compilation.name}" }
+    override val baseName: String by project.provider {
+        if (compilation.isMainCompilationData())
+            project.name
+        else "${project.name}_${compilation.compilationPurpose}"
+    }
 
     // Store as an explicit provider in order to allow Gradle Instant Execution to capture the state
 //    private val allSourceProvider = compilation.map { project.files(it.allSources).asFileTree }
@@ -390,10 +397,7 @@ constructor(
 
 
     private val friendModule: FileCollection by project.provider {
-        project.files(
+        project.files(compilation.friendPaths)
-            compilation.associateWithTransitiveClosure.map { it.output.allOutputs },
-            compilation.friendArtifacts
-        )
     }
     // endregion.
 
@@ -934,7 +938,7 @@ open class CInteropProcess @Inject constructor(@get:Internal val settings: Defau
     val baseKlibName: String
         @Input get() {
             val compilationPrefix = settings.compilation.let {
-                if (it.isMain()) project.name else it.name
+                if (it.isMainCompilationData()) project.name else it.compilationPurpose
             }
             return "$compilationPrefix-cinterop-$interopName"
         }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/KotlinCompileCommon.kt

@@ -24,8 +24,7 @@ import org.gradle.api.tasks.PathSensitivity
 import org.jetbrains.kotlin.cli.common.arguments.K2MetadataCompilerArguments
 import org.jetbrains.kotlin.compilerRunner.GradleCompilerEnvironment
 import org.jetbrains.kotlin.compilerRunner.OutputItemsCollectorImpl
-import org.jetbrains.kotlin.gradle.dsl.KotlinCommonCompile
+import org.jetbrains.kotlin.gradle.dsl.*
-import org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformCommonOptions
 import org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformCommonOptionsImpl
 import org.jetbrains.kotlin.gradle.dsl.fillDefaultValues
 import org.jetbrains.kotlin.gradle.internal.tasks.allOutputFiles
@@ -34,7 +33,8 @@ import org.jetbrains.kotlin.gradle.plugin.KotlinCompilation
 import org.jetbrains.kotlin.gradle.plugin.KotlinSourceSet
 import org.jetbrains.kotlin.gradle.plugin.KotlinTarget
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinCommonCompilation
-import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinFragmentMetadataCompilationData
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.AbstractKotlinFragmentMetadataCompilationData
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinMetadataCompilationData
 import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.refinesClosure
 import org.jetbrains.kotlin.gradle.utils.getValue
 import org.jetbrains.kotlin.gradle.plugin.sources.resolveAllDependsOnSourceSets
@@ -63,7 +63,7 @@ open class KotlinCompileCommon : AbstractKotlinCompile<K2MetadataCompilerArgumen
         args.moduleName = this@KotlinCompileCommon.moduleName
 
         if ((taskData.compilation as? KotlinCommonCompilation)?.isKlibCompilation == true ||
-            taskData.compilation is KotlinFragmentMetadataCompilationData
+            taskData.compilation is KotlinMetadataCompilationData
         ) {
             args.expectActualLinker = true
         }
@@ -84,13 +84,10 @@ open class KotlinCompileCommon : AbstractKotlinCompile<K2MetadataCompilerArgumen
     }
 
     private fun outputPathsFromMetadataCompilationsOf(sourceSets: Iterable<KotlinSourceSet>): List<File> {
-        val target = taskData.compilation.owner
+        val metadataTarget = taskData.compilation.owner as KotlinTarget
-        return when (target) {
+        return sourceSets
-            is KotlinTarget -> sourceSets
+            .mapNotNull { sourceSet -> metadataTarget.compilations.findByName(sourceSet.name)?.output?.classesDirs }
-                .mapNotNull { sourceSet -> target.compilations.findByName(sourceSet.name)?.output?.classesDirs }
+            .flatten()
-                .flatten()
-            else -> error("unexpected compilation owner") // FIXME support PM20 variant
-        }
     }
 
     @get:PathSensitive(PathSensitivity.RELATIVE)
@@ -101,7 +98,7 @@ open class KotlinCompileCommon : AbstractKotlinCompile<K2MetadataCompilerArgumen
                 val defaultKotlinSourceSet: KotlinSourceSet = compilation.defaultSourceSet
                 outputPathsFromMetadataCompilationsOf(defaultKotlinSourceSet.resolveAllDependsOnSourceSets())
             }
-            is KotlinFragmentMetadataCompilationData -> {
+            is AbstractKotlinFragmentMetadataCompilationData -> {
                 val fragment = compilation.fragment
                 project.files(
                     fragment.refinesClosure.minus(fragment).map {
@@ -109,7 +106,7 @@ open class KotlinCompileCommon : AbstractKotlinCompile<K2MetadataCompilerArgumen
                     }
                 )
             }
-            else -> error("unexpected compilation type") // FIXME support PM20 variant
+            else -> error("unexpected compilation type")
         }
     }
 

libraries/tools/kotlin-project-model/src/main/kotlin/DependencyResolution.kt

@@ -25,15 +25,15 @@ interface KotlinDependencyGraphResolver {
     fun resolveDependencyGraph(requestingModule: KotlinModule): DependencyGraphResolution
 }
 
-sealed class DependencyGraphResolution(val requestingModule: KotlinModule) {
+sealed class DependencyGraphResolution(open val requestingModule: KotlinModule) {
     class Unknown(requestingModule: KotlinModule) : DependencyGraphResolution(requestingModule)
-    class DependencyGraph(requestingModule: KotlinModule, val root: DependencyGraphNode): DependencyGraphResolution(requestingModule)
+    open class DependencyGraph(requestingModule: KotlinModule, open val root: DependencyGraphNode): DependencyGraphResolution(requestingModule)
 }
 
 // TODO: should this be a single graph for all dependency scopes as well, not just for all fragments?
-class DependencyGraphNode(
+open class DependencyGraphNode(
-    val module: KotlinModule,
+    open val module: KotlinModule,
-    val dependenciesByFragment: Map<KotlinModuleFragment, Iterable<DependencyGraphNode>>
+    open val dependenciesByFragment: Map<KotlinModuleFragment, Iterable<DependencyGraphNode>>
 ) {
     override fun toString(): String = "node ${module}"
 }