Allow running compiler only for libraries (#1508)

backend.native/build.gradle

@@ -256,3 +256,16 @@ protobuf {
         artifact = "com.google.protobuf:protoc:${protobufVersion}"
     }
 }
+
+task debugCompiler(type: JavaExec) {
+    dependsOn ':dist'
+    main = 'org.jetbrains.kotlin.cli.bc.K2NativeKt'
+    classpath = project.fileTree("${distDir.canonicalPath}/konan/lib/") {
+        include '*.jar'
+    }
+    jvmArgs "-Dkonan.home=${distDir.canonicalPath}",
+            "-Djava.library.path=${distDir.canonicalPath}/konan/nativelib"
+    enableAssertions = true
+    args = findProperty("konan.debug.args").toString().tokenize() ?: []
+}
+

backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2Native.kt

@@ -24,7 +24,7 @@ import org.jetbrains.kotlin.backend.konan.util.profile
 import org.jetbrains.kotlin.cli.common.CLICompiler
 import org.jetbrains.kotlin.cli.common.CLITool
 import org.jetbrains.kotlin.cli.common.ExitCode
-import org.jetbrains.kotlin.cli.common.messages.CompilerMessageSeverity.ERROR
+import org.jetbrains.kotlin.cli.common.messages.CompilerMessageSeverity.*
 import org.jetbrains.kotlin.cli.jvm.compiler.EnvironmentConfigFiles
 import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment
 import org.jetbrains.kotlin.config.CompilerConfiguration
@@ -49,15 +49,21 @@ class K2Native : CLICompiler<K2NativeCompilerArguments>() {
             return ExitCode.OK
         }
 
-        if (arguments.freeArgs.isEmpty() && !arguments.isUsefulWithoutFreeArgs) {
-            configuration.report(ERROR, "You have not specified any compilation arguments. No output has been produced.")
-        }
-
         val environment = KotlinCoreEnvironment.createForProduction(rootDisposable,
             configuration, EnvironmentConfigFiles.NATIVE_CONFIG_FILES)
         val project = environment.project
         val konanConfig = KonanConfig(project, configuration)
 
+        val enoughArguments = arguments.freeArgs.isNotEmpty() || arguments.isUsefulWithoutFreeArgs
+        if (!enoughArguments) {
+            configuration.report(ERROR, "You have not specified any compilation arguments. No output has been produced.")
+        }
+
+        if (konanConfig.linkOnly) {
+            configuration.report(WARNING, "You have not specified any source files. " +
+                    "Only libraries will be used to produce the output binary.")
+        }
+
         try {
             runTopLevelPhases(konanConfig, environment)
         } catch (e: KonanCompilationException) {
@@ -78,7 +84,7 @@ class K2Native : CLICompiler<K2NativeCompilerArguments>() {
     }
 
     val K2NativeCompilerArguments.isUsefulWithoutFreeArgs: Boolean
-        get() = this.listTargets || this.listPhases || this.checkDependencies
+        get() = this.listTargets || this.listPhases || this.checkDependencies || this.libraries?.isNotEmpty() ?: false
 
     fun Array<String>?.toNonNullList(): List<String> {
         return this?.asList<String>() ?: listOf<String>()

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/KonanConfig.kt

@@ -27,6 +27,7 @@ import org.jetbrains.kotlin.cli.common.messages.CompilerMessageSeverity
 import org.jetbrains.kotlin.cli.common.messages.CompilerMessageSeverity.*
 import org.jetbrains.kotlin.config.CommonConfigurationKeys
 import org.jetbrains.kotlin.config.CompilerConfiguration
+import org.jetbrains.kotlin.config.kotlinSourceRoots
 import org.jetbrains.kotlin.descriptors.impl.ModuleDescriptorImpl
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.konan.TempFiles
@@ -48,6 +49,11 @@ class KonanConfig(val project: Project, val configuration: CompilerConfiguration
     internal val targetManager = platformManager.targetManager(configuration.get(KonanConfigKeys.TARGET))
     internal val target = targetManager.target
 
+    val linkOnly: Boolean =
+            configuration.kotlinSourceRoots.isEmpty() && libraryNames.isNotEmpty() && produce.isNativeBinary
+
+    val infoArgsOnly = configuration.kotlinSourceRoots.isEmpty() && !linkOnly
+
     init {
         if (!platformManager.isEnabled(target)) {
             error("Target ${target.visibleName} is not available on the ${HostManager.hostName} host")

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/KonanDriver.kt

@@ -43,7 +43,7 @@ fun runTopLevelPhases(konanConfig: KonanConfig, environment: KotlinCoreEnvironme
         KonanPhases.list()
     }
 
-    if (config.kotlinSourceRoots.isEmpty()) return
+    if (konanConfig.infoArgsOnly) return
 
     val context = Context(konanConfig)