Change default module name from project.name to archivesBaseName;

Get rid of `_main` for the main module.

Issue #KT-17355 Fixed

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

@@ -558,4 +558,28 @@ class KotlinGradleIT: BaseGradleIT() {
             assertNoSuchFile("build/kotlin-classes")
         }
     }
+
+    @Test
+    fun testArchiveBaseNameForModuleName() {
+        val project = Project("simpleProject", "4.0")
+        project.setupWorkingDir()
+
+        val archivesBaseName = "myArchivesBaseName"
+
+        val buildGradle = File(project.projectDir, "build.gradle")
+        buildGradle.appendText("\narchivesBaseName = '$archivesBaseName'")
+
+        // Add top-level members to force generation of the *.kotlin_module files for the two source sets
+        val mainHelloWorldKt = File(project.projectDir, "src/main/kotlin/helloWorld.kt")
+        mainHelloWorldKt.appendText("\nfun topLevelFun() = 1")
+        val deployKotlinSrcKt = File(project.projectDir, "src/deploy/kotlin/kotlinSrc.kt")
+        deployKotlinSrcKt.appendText("\nfun topLevelFun() = 1")
+
+        project.build("build", "compileDeployKotlin") {
+            assertSuccessful()
+            // Main source set should have a *.kotlin_module file without '_main'
+            assertFileExists("build/classes/kotlin/main/META-INF/$archivesBaseName.kotlin_module")
+            assertFileExists("build/classes/kotlin/deploy/META-INF/${archivesBaseName}_deploy.kotlin_module")
+        }
+    }
 }

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

@@ -20,6 +20,7 @@ import org.gradle.api.Project
 import org.gradle.api.Task
 import org.gradle.api.file.SourceDirectorySet
 import org.gradle.api.logging.Logger
+import org.gradle.api.plugins.BasePluginConvention
 import org.gradle.api.tasks.Input
 import org.gradle.api.tasks.SourceTask
 import org.gradle.api.tasks.TaskAction
@@ -132,7 +133,12 @@ abstract class AbstractKotlinCompile<T : CommonCompilerArguments>() : AbstractKo
     internal var javaOutputDir: File? = null
     internal var sourceSetName: String by Delegates.notNull()
     internal val moduleName: String
-            get() = "${project.name}_$sourceSetName"
+        get() {
+            val baseName = project.convention.findPlugin(BasePluginConvention::class.java)?.archivesBaseName
+                    ?: project.name
+            val suffix = if (sourceSetName == "main") "" else "_$sourceSetName"
+            return "$baseName$suffix"
+        }
 
     @Suppress("UNCHECKED_CAST")
     protected val friendTask: AbstractKotlinCompile<T>?