[K/N][gradle] Automatic cleaning of the class loaders map

kotlin-native/build.gradle

@@ -28,6 +28,7 @@ import org.jetbrains.kotlin.CompareDistributionSignatures
 import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
 import org.apache.tools.ant.filters.ReplaceTokens
 import org.jetbrains.kotlin.UtilsKt
+import java.util.concurrent.ConcurrentHashMap
 
 buildscript {
     apply from: "gradle/kotlinGradlePlugin.gradle"
@@ -95,6 +96,9 @@ ext {
 
     konanVersionFull = ext.kotlinNativeVersion
     gradlePluginVersion = konanVersionFull
+
+    // A separate map for each build for automatic cleaning the daemon after the build have finished.
+    toolClassLoadersMap = new ConcurrentHashMap<Object, URLClassLoader>()
 }
 
 allprojects {

kotlin-native/tools/kotlin-native-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/konan/KonanToolRunner.kt

@@ -28,6 +28,8 @@ import java.io.File
 import java.util.Properties
 import org.jetbrains.kotlin.compilerRunner.KotlinToolRunner
 import org.jetbrains.kotlin.konan.target.AbstractToolConfig
+import java.net.URLClassLoader
+import java.util.concurrent.ConcurrentHashMap
 
 internal interface KonanToolRunner {
     fun run(args: List<String>)
@@ -68,10 +70,15 @@ internal abstract class KonanCliRunner(
             """.trimIndent()
             }
 
-    data class IsolatedClassLoaderCacheKey(val classpath: Set<java.io.File>, val project: Project)
+    data class IsolatedClassLoaderCacheKey(val classpath: Set<File>)
 
     // TODO: can't we use this for other implementations too?
-    final override val isolatedClassLoaderCacheKey get() = IsolatedClassLoaderCacheKey(classpath, project)
+    final override val isolatedClassLoaderCacheKey get() = IsolatedClassLoaderCacheKey(classpath)
+
+    // A separate map for each build for automatic cleaning the daemon after the build have finished.
+    @Suppress("UNCHECKED_CAST")
+    final override val isolatedClassLoaders get() =
+        project.project(":kotlin-native").ext["toolClassLoadersMap"] as ConcurrentHashMap<Any, URLClassLoader>
 
     override fun transformArgs(args: List<String>) = listOf(toolName) + args
 
@@ -110,6 +117,9 @@ private val load0 = Runtime::class.java.getDeclaredMethod("load0", Class::class.
 
 internal class CliToolConfig(konanHome: String, target: String) : AbstractToolConfig(konanHome, target, emptyMap()) {
     override fun loadLibclang() {
+        // Load libclang into the system class loader. This is needed to allow developers to make changes
+        // in the tooling infrastructure without having to stop the daemon (otherwise libclang might end up
+        // loaded in two different class loaders which is not allowed by the JVM).
         load0.invoke(Runtime.getRuntime(), String::class.java, libclang)
     }
 }