diff --git a/compiler/incremental-compilation-impl/src/org/jetbrains/kotlin/incremental/IncrementalCompilerRunner.kt b/compiler/incremental-compilation-impl/src/org/jetbrains/kotlin/incremental/IncrementalCompilerRunner.kt
index 8f368c51731..e28ddd44462 100644
--- a/compiler/incremental-compilation-impl/src/org/jetbrains/kotlin/incremental/IncrementalCompilerRunner.kt
+++ b/compiler/incremental-compilation-impl/src/org/jetbrains/kotlin/incremental/IncrementalCompilerRunner.kt
@@ -105,8 +105,7 @@ abstract class IncrementalCompilerRunner<
                 is ChangedFiles.Unknown -> CompilationMode.Rebuild { "inputs' changes are unknown (first or clean build)" }
             }
 
-    protected open fun calculateSourcesToCompile(caches: CacheManager, changedFiles: ChangedFiles.Known, args: Args): CompilationMode =
-            CompilationMode.Incremental(getDirtyFiles(changedFiles))
+    protected abstract fun calculateSourcesToCompile(caches: CacheManager, changedFiles: ChangedFiles.Known, args: Args): CompilationMode
 
     protected fun getDirtyFiles(changedFiles: ChangedFiles.Known): HashSet<File> {
         val dirtyFiles = HashSet<File>(with(changedFiles) { modified.size + removed.size })