Add support for JS source map source roots to Gradle plugin

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

@@ -6,6 +6,7 @@ import org.junit.Test
 import java.io.File
 import java.util.zip.ZipFile
 import kotlin.test.assertEquals
+import kotlin.test.assertTrue
 
 class Kotlin2JsGradlePluginIT : BaseGradleIT() {
     @Test
@@ -170,4 +171,20 @@ class Kotlin2JsGradlePluginIT : BaseGradleIT() {
             assertSuccessful()
         }
     }
+
+    @Test
+    fun testKotlinJsSourceMap() {
+        val project = Project("kotlin2JsProjectWithSourceMap", "2.10")
+
+        project.build("build") {
+            assertSuccessful()
+
+            val mapFilePath = "build/kotlin2js/main/app.js.map"
+            assertFileExists(mapFilePath)
+            val map = fileInWorkingDir(mapFilePath).readText()
+
+            val sourceFilePath = "prefixprefix/example/main.kt"
+            assertTrue("Source map should contain reference to $sourceFilePath") { map.contains("\"$sourceFilePath\"") }
+        }
+    }
 }

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin2JsProjectWithSourceMap/build.gradle

@@ -0,0 +1,24 @@
+buildscript {
+    repositories {
+        mavenLocal()
+    }
+    dependencies {
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+    }
+}
+
+apply plugin: "kotlin2js"
+
+repositories {
+    mavenLocal()
+}
+
+dependencies {
+    compile "org.jetbrains.kotlin:kotlin-stdlib-js:$kotlin_version"
+}
+
+compileKotlin2Js.kotlinOptions.sourceMap = true
+compileKotlin2Js.kotlinOptions.sourceMapPrefix = "prefixprefix/"
+compileKotlin2Js.kotlinOptions.outputFile = "${buildDir}/kotlin2js/main/app.js"
+compileKotlin2Js.kotlinOptions.suppressWarnings = true
+compileKotlin2Js.kotlinOptions.verbose = true

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin2JsProjectWithSourceMap/src/main/kotlin/example/main.kt

@@ -0,0 +1,5 @@
+package example
+
+fun main(args: Array<String>) {
+    println("Hello")
+}

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

@@ -210,6 +210,9 @@ internal class Kotlin2JsSourceSetProcessor(
 
             sourceSet.output.setClassesDir(outputDir)
             kotlinTask.destinationDir = outputDir
+
+            kotlinTask.kotlinOptions.sourceMapSourceRoots =
+                    sourceSet.allSource.srcDirs.joinToString(File.pathSeparator) { it.absolutePath }
         }
     }