[JS IR] Add gradle plugin integration tests

libraries/tools/kotlin-gradle-plugin-integration-tests/build.gradle.kts

@@ -105,8 +105,10 @@ tasks.withType<Test> {
         ":kotlin-reflect:install",
         ":kotlin-annotation-processing-gradle:install",
         ":kotlin-test:kotlin-test-jvm:install",
+        ":kotlin-test:kotlin-test-js:install",
         ":kotlin-gradle-subplugin-example:install",
         ":kotlin-stdlib-jdk8:install",
+        ":kotlin-stdlib-js:install",
         ":examples:annotation-processor-example:install",
         ":kotlin-scripting-common:install",
         ":kotlin-scripting-jvm:install",

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/BaseGradleIT.kt

@@ -198,6 +198,7 @@ abstract class BaseGradleIT {
         val daemonOptionSupported: Boolean = true,
         val incremental: Boolean? = null,
         val incrementalJs: Boolean? = null,
+        val jsIrBackend: Boolean? = null,
         val androidHome: File? = null,
         val javaHome: File? = null,
         val androidGradlePluginVersion: AGPVersion? = null,
@@ -719,6 +720,7 @@ Finished executing task ':$taskName'|
                 add("-Pkotlin.incremental=$it")
             }
             options.incrementalJs?.let { add("-Pkotlin.incremental.js=$it") }
+            options.jsIrBackend?.let { add("-Pkotlin.js.useIrBackend=$it") }
             options.usePreciseJavaTracking?.let { add("-Pkotlin.incremental.usePreciseJavaTracking=$it") }
             options.androidGradlePluginVersion?.let { add("-Pandroid_tools_version=$it") }
             if (options.debug) {

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/Kotlin2JsGradlePluginIT.kt

@@ -2,169 +2,20 @@ package org.jetbrains.kotlin.gradle
 
 import org.gradle.api.logging.LogLevel
 import org.jetbrains.kotlin.gradle.tasks.USING_JS_INCREMENTAL_COMPILATION_MESSAGE
+import org.jetbrains.kotlin.gradle.tasks.USING_JS_IR_BACKEND_MESSAGE
 import org.jetbrains.kotlin.gradle.util.getFileByName
 import org.jetbrains.kotlin.gradle.util.getFilesByNames
 import org.jetbrains.kotlin.gradle.util.modify
+import org.junit.Assume.assumeFalse
 import org.junit.Test
 import java.io.File
 import java.util.zip.ZipFile
 import kotlin.test.assertEquals
 import kotlin.test.assertTrue
 
-class Kotlin2JsGradlePluginIT : BaseGradleIT() {
+class Kotlin2JsIrGradlePluginIT : AbstractKotlin2JsGradlePluginIT(true)
-    @Test
-    fun testBuildAndClean() {
-        val project = Project("kotlin2JsProject")
-
-        project.build("build") {
-            assertSuccessful()
-            assertReportExists()
-
-            assertTasksExecuted(
-                ":libraryProject:jarSources",
-                ":mainProject:compileKotlin2Js",
-                ":libraryProject:compileKotlin2Js"
-            )
-
-            listOf(
-                "mainProject/web/js/app.js",
-                "mainProject/web/js/lib/kotlin.js",
-                "libraryProject/build/kotlin2js/main/test-library.js",
-                "mainProject/web/js/app.js.map"
-            ).forEach { assertFileExists(it) }
-        }
-
-        project.build("build") {
-            assertSuccessful()
-            assertTasksUpToDate(":mainProject:compileKotlin2Js")
-            assertContainsRegex(":libraryProject:compileTestKotlin2Js (UP-TO-DATE|NO-SOURCE)".toRegex())
-        }
-
-        project.build("clean") {
-            assertSuccessful()
-            assertReportExists()
-
-            // Test that we don't accidentally remove the containing directory
-            // This would fail if we used the default clean task of the copy task
-            assertFileExists("mainProject/web/js/lib")
-
-            assertNoSuchFile("main/project/web/js/app.js.map")
-            assertNoSuchFile("main/project/web/js/example/main.kt")
-        }
-
-        project.build("clean") {
-            assertSuccessful()
-            assertReportExists()
-        }
-    }
-
-    @Test
-    fun testJarIncludesJsDefaultOutput() {
-        val project = Project("kotlin2JsNoOutputFileProject")
-
-        project.build("jar") {
-            assertSuccessful()
-
-            assertTasksExecuted(":compileKotlin2Js")
-            val jarPath = "build/libs/kotlin2JsNoOutputFileProject.jar"
-            assertFileExists(jarPath)
-            val jar = ZipFile(fileInWorkingDir(jarPath))
-            assertEquals(
-                1, jar.entries().asSequence().count { it.name == "kotlin2JsNoOutputFileProject.js" },
-                "The jar should contain an entry `kotlin2JsNoOutputFileProject.js` with no duplicates"
-            )
-        }
-    }
-
-    @Test
-    fun testJarIncludesJsOutputSetExplicitly() {
-        val project = Project("kotlin2JsModuleKind")
-
-        project.build(":jar") {
-            assertSuccessful()
-
-            assertTasksExecuted(":compileKotlin2Js")
-            val jarPath = "build/libs/kotlin2JsModuleKind.jar"
-            assertFileExists(jarPath)
-            val jar = ZipFile(fileInWorkingDir(jarPath))
-            assertEquals(
-                1, jar.entries().asSequence().count { it.name == "app.js" },
-                "The jar should contain an entry `app.js` with no duplicates"
-            )
-        }
-    }
-
-    @Test
-    fun testModuleKind() {
-        val project = Project("kotlin2JsModuleKind")
-
-        project.build("runRhino") {
-            assertSuccessful()
-        }
-    }
-
-    @Test
-    fun testDefaultOutputFile() {
-        val project = Project("kotlin2JsNoOutputFileProject")
-
-        project.build("build") {
-            assertSuccessful()
-            assertFileExists(kotlinClassesDir() + "kotlin2JsNoOutputFileProject.js")
-            assertFileExists(kotlinClassesDir(sourceSet = "test") + "kotlin2JsNoOutputFileProject_test.js")
-        }
-    }
-
-    @Test
-    fun testCompileTestCouldAccessProduction() {
-        val project = Project("kotlin2JsProjectWithTests")
-
-        project.build("build") {
-            assertSuccessful()
-
-            assertTasksExecuted(
-                ":compileKotlin2Js",
-                ":compileTestKotlin2Js"
-            )
-
-            assertFileExists("build/kotlin2js/main/module.js")
-            assertFileExists("build/kotlin2js/test/module-tests.js")
-        }
-    }
-
-    @Test
-    fun testCompilerTestAccessInternalProduction() {
-        val project = Project("kotlin2JsInternalTest")
-
-        project.build("runRhino") {
-            assertSuccessful()
-        }
-    }
-
-    @Test
-    fun testJsCustomSourceSet() {
-        val project = Project("kotlin2JsProjectWithCustomSourceset")
-
-        project.build("build") {
-            assertSuccessful()
-
-            assertTasksExecuted(
-                ":compileKotlin2Js",
-                ":compileIntegrationTestKotlin2Js"
-            )
-
-            assertFileExists("build/kotlin2js/main/module.js")
-            assertFileExists("build/kotlin2js/integrationTest/module-inttests.js")
-
-            val jarPath = "build/libs/kotlin2JsProjectWithCustomSourceset-inttests.jar"
-            assertFileExists(jarPath)
-            val jar = ZipFile(fileInWorkingDir(jarPath))
-            assertEquals(
-                1, jar.entries().asSequence().count { it.name == "module-inttests.js" },
-                "The jar should contain an entry `module-inttests.js` with no duplicates"
-            )
-        }
-    }
 
+class Kotlin2JsGradlePluginIT : AbstractKotlin2JsGradlePluginIT(false) {
     @Test
     fun testKotlinJsBuiltins() {
         val project = Project("kotlinBuiltins")
@@ -180,49 +31,6 @@ class Kotlin2JsGradlePluginIT : BaseGradleIT() {
         }
     }
 
-    @Test
-    fun testKotlinJsSourceMap() {
-        val project = Project("kotlin2JsNoOutputFileProject")
-
-        project.setupWorkingDir()
-
-        project.projectDir.getFileByName("build.gradle").modify {
-            it + "\n" +
-                    "compileKotlin2Js.kotlinOptions.sourceMap = true\n" +
-                    "compileKotlin2Js.kotlinOptions.sourceMapPrefix = \"prefixprefix/\"\n" +
-                    "compileKotlin2Js.kotlinOptions.outputFile = \"\${buildDir}/kotlin2js/main/app.js\"\n"
-        }
-
-        project.build("build") {
-            assertSuccessful()
-
-            val mapFilePath = "build/kotlin2js/main/app.js.map"
-            assertFileExists(mapFilePath)
-            val map = fileInWorkingDir(mapFilePath).readText()
-
-            val sourceFilePath = "prefixprefix/src/main/kotlin/example/Dummy.kt"
-            assertTrue("Source map should contain reference to $sourceFilePath") { map.contains("\"$sourceFilePath\"") }
-        }
-    }
-
-    @Test
-    fun testKotlinJsSourceMapInline() {
-        val project = Project("kotlin2JsProjectWithSourceMapInline")
-
-        project.build("build") {
-            assertSuccessful()
-
-            val mapFilePath = kotlinClassesDir(subproject = "app") + "app.js.map"
-            assertFileExists(mapFilePath)
-            val map = fileInWorkingDir(mapFilePath).readText()
-
-            assertTrue("Source map should contain reference to main.kt") { map.contains("\"./src/main/kotlin/main.kt\"") }
-            assertTrue("Source map should contain reference to foo.kt") { map.contains("\"./src/main/kotlin/foo.kt\"") }
-            assertTrue("Source map should contain source of main.kt") { map.contains("\"fun main(args: Array<String>) {") }
-            assertTrue("Source map should contain source of foo.kt") { map.contains("\"inline fun foo(): String {") }
-        }
-    }
-
     @Test
     fun testDce() {
         val project = Project("kotlin2JsDceProject", minLogLevel = LogLevel.INFO)
@@ -305,6 +113,239 @@ class Kotlin2JsGradlePluginIT : BaseGradleIT() {
             assertTrue(fileInWorkingDir("$pathPrefix/kotlin.js").length() < 500 * 1000, "Looks like kotlin.js file was not minified by DCE")
         }
     }
+}
+
+abstract class AbstractKotlin2JsGradlePluginIT(private val irBackend: Boolean) : BaseGradleIT() {
+    override fun defaultBuildOptions(): BuildOptions =
+        super.defaultBuildOptions().copy(jsIrBackend = irBackend)
+
+    private fun CompiledProject.checkIrCompilationMessage() {
+        if (irBackend) {
+            assertContains(USING_JS_IR_BACKEND_MESSAGE)
+        } else {
+            assertNotContains(USING_JS_IR_BACKEND_MESSAGE)
+        }
+    }
+
+    @Test
+    fun testBuildAndClean() {
+        val project = Project("kotlin2JsProject")
+
+        project.build("build") {
+            assertSuccessful()
+            assertReportExists()
+            checkIrCompilationMessage()
+
+            assertTasksExecuted(
+                ":libraryProject:jarSources",
+                ":mainProject:compileKotlin2Js",
+                ":libraryProject:compileKotlin2Js"
+            )
+
+            assertFileExists("mainProject/web/js/app.js")
+            if (!irBackend) {
+                assertFileExists("mainProject/web/js/lib/kotlin.js")
+                assertFileExists("libraryProject/build/kotlin2js/main/test-library.js")
+                assertFileExists("mainProject/web/js/app.js.map")
+            }
+        }
+
+        project.build("build") {
+            assertSuccessful()
+            assertTasksUpToDate(":mainProject:compileKotlin2Js")
+            assertContainsRegex(":libraryProject:compileTestKotlin2Js (UP-TO-DATE|NO-SOURCE)".toRegex())
+        }
+
+        project.build("clean") {
+            assertSuccessful()
+            assertReportExists()
+
+            // Test that we don't accidentally remove the containing directory
+            // This would fail if we used the default clean task of the copy task
+            assertFileExists("mainProject/web/js/lib")
+
+            assertNoSuchFile("main/project/web/js/app.js.map")
+            assertNoSuchFile("main/project/web/js/example/main.kt")
+        }
+
+        project.build("clean") {
+            assertSuccessful()
+            assertReportExists()
+        }
+    }
+
+    @Test
+    fun testJarIncludesJsDefaultOutput() {
+        val project = Project("kotlin2JsNoOutputFileProject")
+
+        project.build("jar") {
+            assertSuccessful()
+            checkIrCompilationMessage()
+
+            assertTasksExecuted(":compileKotlin2Js")
+            val jarPath = "build/libs/kotlin2JsNoOutputFileProject.jar"
+            assertFileExists(jarPath)
+            val jar = ZipFile(fileInWorkingDir(jarPath))
+            assertEquals(
+                1, jar.entries().asSequence().count { it.name == "kotlin2JsNoOutputFileProject.js" },
+                "The jar should contain an entry `kotlin2JsNoOutputFileProject.js` with no duplicates"
+            )
+        }
+    }
+
+    @Test
+    fun testJarIncludesJsOutputSetExplicitly() {
+        val project = Project("kotlin2JsModuleKind")
+
+        project.build(":jar") {
+            assertSuccessful()
+            checkIrCompilationMessage()
+
+            assertTasksExecuted(":compileKotlin2Js")
+            val jarPath = "build/libs/kotlin2JsModuleKind.jar"
+            assertFileExists(jarPath)
+            val jar = ZipFile(fileInWorkingDir(jarPath))
+            assertEquals(
+                1, jar.entries().asSequence().count { it.name == "app.js" },
+                "The jar should contain an entry `app.js` with no duplicates"
+            )
+        }
+    }
+
+    @Test
+    fun testModuleKind() {
+        val project = Project("kotlin2JsModuleKind")
+
+        project.build("runRhino") {
+            assertSuccessful()
+            checkIrCompilationMessage()
+        }
+    }
+
+    @Test
+    fun testDefaultOutputFile() {
+        val project = Project("kotlin2JsNoOutputFileProject")
+
+        project.build("build") {
+            assertSuccessful()
+            checkIrCompilationMessage()
+            if (irBackend) {
+                assertFileExists(kotlinClassesDir() + "manifest")
+            } else {
+                assertFileExists(kotlinClassesDir() + "kotlin2JsNoOutputFileProject.js")
+            }
+            assertFileExists(kotlinClassesDir(sourceSet = "test") + "kotlin2JsNoOutputFileProject_test.js")
+        }
+    }
+
+    @Test
+    fun testCompileTestCouldAccessProduction() {
+        val project = Project("kotlin2JsProjectWithTests")
+
+        project.build("build") {
+            assertSuccessful()
+            checkIrCompilationMessage()
+
+            assertTasksExecuted(
+                ":compileKotlin2Js",
+                ":compileTestKotlin2Js"
+            )
+            if (irBackend) {
+                assertFileExists("build/kotlin2js/main/manifest")
+            } else {
+                assertFileExists("build/kotlin2js/main/module.js")
+            }
+            assertFileExists("build/kotlin2js/test/module-tests.js")
+        }
+    }
+
+    @Test
+    fun testCompilerTestAccessInternalProduction() {
+        val project = Project("kotlin2JsInternalTest")
+
+        project.build("runRhino") {
+            assertSuccessful()
+            checkIrCompilationMessage()
+        }
+    }
+
+    @Test
+    fun testJsCustomSourceSet() {
+        val project = Project("kotlin2JsProjectWithCustomSourceset")
+
+        project.build("build") {
+            assertSuccessful()
+            checkIrCompilationMessage()
+
+            assertTasksExecuted(
+                ":compileKotlin2Js",
+                ":compileIntegrationTestKotlin2Js"
+            )
+
+            if (!irBackend) {
+                assertFileExists("build/kotlin2js/main/module.js")
+            }
+            assertFileExists("build/kotlin2js/integrationTest/module-inttests.js")
+
+            val jarPath = "build/libs/kotlin2JsProjectWithCustomSourceset-inttests.jar"
+            assertFileExists(jarPath)
+            val jar = ZipFile(fileInWorkingDir(jarPath))
+            assertEquals(
+                1, jar.entries().asSequence().count { it.name == "module-inttests.js" },
+                "The jar should contain an entry `module-inttests.js` with no duplicates"
+            )
+        }
+    }
+
+
+    @Test
+    fun testKotlinJsSourceMap() {
+        // TODO: Support source maps
+        assumeFalse(irBackend)
+
+        val project = Project("kotlin2JsNoOutputFileProject")
+
+        project.setupWorkingDir()
+
+        project.projectDir.getFileByName("build.gradle").modify {
+            it + "\n" +
+                    "compileKotlin2Js.kotlinOptions.sourceMap = true\n" +
+                    "compileKotlin2Js.kotlinOptions.sourceMapPrefix = \"prefixprefix/\"\n" +
+                    "compileKotlin2Js.kotlinOptions.outputFile = \"\${buildDir}/kotlin2js/main/app.js\"\n"
+        }
+
+        project.build("build") {
+            assertSuccessful()
+
+            val mapFilePath = "build/kotlin2js/main/app.js.map"
+            assertFileExists(mapFilePath)
+            val map = fileInWorkingDir(mapFilePath).readText()
+
+            val sourceFilePath = "prefixprefix/src/main/kotlin/example/Dummy.kt"
+            assertTrue("Source map should contain reference to $sourceFilePath") { map.contains("\"$sourceFilePath\"") }
+        }
+    }
+
+    @Test
+    fun testKotlinJsSourceMapInline() {
+        // TODO: Support source maps
+        assumeFalse(irBackend)
+
+        val project = Project("kotlin2JsProjectWithSourceMapInline")
+
+        project.build("build") {
+            assertSuccessful()
+
+            val mapFilePath = kotlinClassesDir(subproject = "app") + "app.js.map"
+            assertFileExists(mapFilePath)
+            val map = fileInWorkingDir(mapFilePath).readText()
+
+            assertTrue("Source map should contain reference to main.kt") { map.contains("\"./src/main/kotlin/main.kt\"") }
+            assertTrue("Source map should contain reference to foo.kt") { map.contains("\"./src/main/kotlin/foo.kt\"") }
+            assertTrue("Source map should contain source of main.kt") { map.contains("\"fun main(args: Array<String>) {") }
+            assertTrue("Source map should contain source of foo.kt") { map.contains("\"inline fun foo(): String {") }
+        }
+    }
 
     /** Issue: KT-18495 */
     @Test
@@ -312,6 +353,7 @@ class Kotlin2JsGradlePluginIT : BaseGradleIT() {
         val project = Project("kotlin2JsProject")
         project.build("build") {
             assertSuccessful()
+            checkIrCompilationMessage()
             assertNotContains("this build assumes a single directory for all classes from a source set")
         }
     }
@@ -320,8 +362,11 @@ class Kotlin2JsGradlePluginIT : BaseGradleIT() {
     fun testIncrementalCompilation() = Project("kotlin2JsICProject").run {
         build("build") {
             assertSuccessful()
-            assertContains(USING_JS_INCREMENTAL_COMPILATION_MESSAGE)
+            checkIrCompilationMessage()
-            assertCompiledKotlinSources(project.relativize(allKotlinFiles))
+            if (!irBackend) { // TODO: Support incremental compilation
+                assertContains(USING_JS_INCREMENTAL_COMPILATION_MESSAGE)
+                assertCompiledKotlinSources(project.relativize(allKotlinFiles))
+            }
         }
 
         build("build") {
@@ -334,9 +379,13 @@ class Kotlin2JsGradlePluginIT : BaseGradleIT() {
         }
         build("build") {
             assertSuccessful()
-            assertContains(USING_JS_INCREMENTAL_COMPILATION_MESSAGE)
+            checkIrCompilationMessage()
-            val affectedFiles = project.projectDir.getFilesByNames("A.kt", "useAInLibMain.kt", "useAInAppMain.kt", "useAInAppTest.kt")
+            // TODO: Support incremental compilation in IR backend
-            assertCompiledKotlinSources(project.relativize(affectedFiles))
+            if (!irBackend) {
+                assertContains(USING_JS_INCREMENTAL_COMPILATION_MESSAGE)
+                val affectedFiles = project.projectDir.getFilesByNames("A.kt", "useAInLibMain.kt", "useAInAppMain.kt", "useAInAppTest.kt")
+                assertCompiledKotlinSources(project.relativize(affectedFiles))
+            }
         }
     }
 
@@ -346,12 +395,14 @@ class Kotlin2JsGradlePluginIT : BaseGradleIT() {
 
         build("build", options = options) {
             assertSuccessful()
+            checkIrCompilationMessage()
             assertNotContains(USING_JS_INCREMENTAL_COMPILATION_MESSAGE)
         }
     }
 
     @Test
     fun testNewKotlinJsPlugin() = with(Project("kotlin-js-plugin-project", GradleVersionRequired.AtLeast("4.10.2"))) {
+        assumeFalse(irBackend) // TODO: Support IR version of kotlinx.html
         setupWorkingDir()
         gradleBuildScript().modify(::transformBuildScriptWithPluginsDsl)
         gradleSettingsScript().modify(::transformBuildScriptWithPluginsDsl)

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin2JsICProject/app/build.gradle

@@ -4,3 +4,9 @@ dependencies {
     compile "org.jetbrains.kotlin:kotlin-stdlib-js:$kotlin_version"
     compile project(":lib")
 }
+
+def isIrBackend = project.findProperty("kotlin.js.useIrBackend")?.toBoolean() ?: false
+if (isIrBackend) {
+    compileKotlin2Js.kotlinOptions.freeCompilerArgs += ["-Xir-produce-klib-dir", "-Xir-only"]
+    compileTestKotlin2Js.kotlinOptions.freeCompilerArgs += ["-Xir-produce-js"]
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin2JsICProject/lib/build.gradle

@@ -3,3 +3,9 @@ apply plugin: 'kotlin2js'
 dependencies {
     compile "org.jetbrains.kotlin:kotlin-stdlib-js:$kotlin_version"
 }
+
+def isIrBackend = project.findProperty("kotlin.js.useIrBackend")?.toBoolean() ?: false
+if (isIrBackend) {
+    compileKotlin2Js.kotlinOptions.freeCompilerArgs += ["-Xir-produce-klib-dir", "-Xir-only"]
+    compileTestKotlin2Js.kotlinOptions.freeCompilerArgs += ["-Xir-produce-js"]
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin2JsInternalTest/build.gradle

@@ -22,11 +22,22 @@ dependencies {
 
 def classesDir = "${buildDir}/classes/kotlin"
 
+def isIrBackend = project.findProperty("kotlin.js.useIrBackend")?.toBoolean() ?: false
+if (isIrBackend) {
+    compileKotlin2Js.kotlinOptions.freeCompilerArgs += ["-Xir-produce-klib-dir", "-Xir-only"]
+    compileTestKotlin2Js.kotlinOptions.freeCompilerArgs += ["-Xir-produce-js"]
+}
+
 task runRhino(type: JavaExec) {
     classpath = sourceSets.main.runtimeClasspath
     workingDir = classesDir
     main = 'org.mozilla.javascript.tools.shell.Main'
-    args = ["-opt", "-1", "-f", "kotlin.js", "-f", "main/kotlin2JsInternalTest.js", "-f", "test/kotlin2JsInternalTest_test.js", "-f", "check.js"]
+    if (isIrBackend) {
+        // IR backend produces a single JS file
+        args = ["-opt", "-1", "test/kotlin2JsInternalTest_test.js", "-f", "check.js"]
+    } else {
+        args = ["-opt", "-1", "-f", "kotlin.js", "-f", "main/kotlin2JsInternalTest.js", "-f", "test/kotlin2JsInternalTest_test.js", "-f", "check.js"]
+    }
 }
 
 build.doLast {

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin2JsInternalTest/src/test/kotlin/tests.kt

@@ -22,6 +22,7 @@ fun <T> assertEquals(e: T, a: T) {
     if (e != a) throw Exception("Expected: $e, actual: $a")
 }
 
+@JsExport
 fun test() {
     assertEquals("CONST", CONST)
 

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin2JsModuleKind/build.gradle

@@ -16,6 +16,10 @@ def outDir = "${buildDir}/kotlin2js/main/"
 compileKotlin2Js.kotlinOptions.moduleKind = "amd"
 compileKotlin2Js.kotlinOptions.outputFile = outDir + "app.js"
 
+if (project.findProperty("kotlin.js.useIrBackend")?.toBoolean() == true) {
+    compileKotlin2Js.kotlinOptions.freeCompilerArgs += ["-Xir-produce-js"]
+}
+
 repositories {
     mavenLocal()
     mavenCentral()

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin2JsModuleKind/src/main/kotlin/org/jetbrains/HelloWorld.kt

@@ -16,4 +16,5 @@
 
 package foo
 
+@JsExport
 fun bar() = "OK"

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin2JsNoOutputFileProject/build.gradle

@@ -18,3 +18,8 @@ repositories {
 dependencies {
     compile "org.jetbrains.kotlin:kotlin-stdlib-js:$kotlin_version"
 }
+
+if (project.findProperty("kotlin.js.useIrBackend")?.toBoolean() == true) {
+    compileKotlin2Js.kotlinOptions.freeCompilerArgs += ["-Xir-produce-klib-dir", "-Xir-produce-js", "-Xir-only"]
+    compileTestKotlin2Js.kotlinOptions.freeCompilerArgs += ["-Xir-produce-js"]
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin2JsProject/libraryProject/build.gradle

@@ -31,12 +31,17 @@ def outDir = "${buildDir}/kotlin2js/main/"
 
 compileKotlin2Js.kotlinOptions.outputFile = outDir + "test-library.js"
 
+def isIrBackend = project.findProperty("kotlin.js.useIrBackend")?.toBoolean()
+if (isIrBackend) {
+    compileKotlin2Js.kotlinOptions.freeCompilerArgs += ["-Xir-produce-klib-dir"]
+}
+
 jar {
     from sourceSets.main.allSource
     include "**/*.kt"
 
     from outDir
-    include "**/*.js"
+    include (isIrBackend ? "**/*" : "**/*.js")
 
     manifest {
         attributes(

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin2JsProject/mainProject/build.gradle

@@ -25,6 +25,10 @@ compileKotlin2Js.kotlinOptions.outputFile = "${projectDir}/web/js/app.js"
 compileKotlin2Js.kotlinOptions.suppressWarnings = true
 compileKotlin2Js.kotlinOptions.verbose = true
 
+if (project.findProperty("kotlin.js.useIrBackend")?.toBoolean() == true) {
+    compileKotlin2Js.kotlinOptions.freeCompilerArgs += ["-Xir-produce-js"]
+}
+
 build.doLast {
     configurations.compile.each { File file ->
         copy {

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin2JsProjectWithCustomSourceset/build.gradle

@@ -29,6 +29,12 @@ compileIntegrationTestKotlin2Js.dependsOn compileKotlin2Js
 compileKotlin2Js.kotlinOptions.outputFile = "${buildDir}/kotlin2js/main/module.js"
 compileIntegrationTestKotlin2Js.kotlinOptions.outputFile = "${buildDir}/kotlin2js/integrationTest/module-inttests.js"
 
+def isIrBackend = project.findProperty("kotlin.js.useIrBackend")?.toBoolean() ?: false
+if (isIrBackend) {
+    compileKotlin2Js.kotlinOptions.freeCompilerArgs += ["-Xir-produce-klib-dir", "-Xir-only"]
+    compileIntegrationTestKotlin2Js.kotlinOptions.freeCompilerArgs += ["-Xir-produce-js"]
+}
+
 dependencies {
     compile "org.jetbrains.kotlin:kotlin-stdlib-js:$kotlin_version"
     integrationTestCompile files(file(compileKotlin2Js.kotlinOptions.outputFile).parent)

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin2JsProjectWithTests/build.gradle

@@ -30,3 +30,8 @@ artifacts {
 
 compileKotlin2Js.kotlinOptions.outputFile = "${buildDir}/kotlin2js/main/module.js"
 compileTestKotlin2Js.kotlinOptions.outputFile = "${buildDir}/kotlin2js/test/module-tests.js"
+
+if (project.findProperty("kotlin.js.useIrBackend")?.toBoolean() == true) {
+    compileKotlin2Js.kotlinOptions.freeCompilerArgs += ["-Xir-produce-klib-dir", "-Xir-only"]
+    compileTestKotlin2Js.kotlinOptions.freeCompilerArgs += ["-Xir-produce-js"]
+}

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

@@ -46,6 +46,7 @@ import javax.inject.Inject
 const val KOTLIN_BUILD_DIR_NAME = "kotlin"
 const val USING_JVM_INCREMENTAL_COMPILATION_MESSAGE = "Using Kotlin/JVM incremental compilation"
 const val USING_JS_INCREMENTAL_COMPILATION_MESSAGE = "Using Kotlin/JS incremental compilation"
+const val USING_JS_IR_BACKEND_MESSAGE = "Using Kotlin/JS IR backend"
 
 abstract class AbstractKotlinCompileTool<T : CommonToolArguments>
     : AbstractCompile(),
@@ -588,8 +589,8 @@ open class Kotlin2JsCompile : AbstractKotlinCompile<K2JSCompilerArguments>(), Ko
         logger.debug("Calling compiler")
         destinationDir.mkdirs()
 
-        if (args.isIrBackendEnabled()) {
+        if (kotlinOptions.isIrBackendEnabled()) {
-            logger.kotlinDebug("Using JS IR backend")
+            logger.info(USING_JS_IR_BACKEND_MESSAGE)
             incremental = false
         }