Write multifile part->facade mapping to .kotlin_module

compiler/backend/src/org/jetbrains/kotlin/codegen/ClassFileFactory.java

@@ -185,13 +185,13 @@ public class ClassFileFactory implements OutputFileCollection {
         final String packageFqNameAsString = packageFqName.asString();
         return new PackagePartRegistry() {
             @Override
-            public void addPart(@NotNull String partShortName) {
+            public void addPart(@NotNull String partShortName, @Nullable String facadeShortName) {
                 PackageParts packageParts = partsGroupedByPackage.get(packageFqNameAsString);
                 if (packageParts == null) {
                     packageParts = new PackageParts(packageFqNameAsString);
                     partsGroupedByPackage.put(packageFqNameAsString, packageParts);
                 }
-                packageParts.addPart(partShortName);
+                packageParts.addPart(partShortName, facadeShortName);
             }
         };
     }

compiler/backend/src/org/jetbrains/kotlin/codegen/MultifileClassCodegen.kt

@@ -215,14 +215,13 @@ class MultifileClassCodegenImpl(
 
         if (!state.generateDeclaredClassFilter.shouldGeneratePackagePart(file) || !file.hasDeclarationsForPartClass()) return
 
-        val partInternalName = partType.internalName
-        packagePartRegistry.addPart(partInternalName.substring(partInternalName.lastIndexOf('/') + 1))
+        packagePartRegistry.addPart(partType.internalName.substringAfterLast('/'), facadeClassType.internalName.substringAfterLast('/'))
 
         val builder = state.factory.newVisitor(MultifileClassPart(file, packageFragment), partType, file)
 
         MultifileClassPartCodegen(
                 builder, file, packageFragment,
-                getSuperClassForPart(partInternalName),
+                getSuperClassForPart(partType.internalName),
                 shouldGeneratePartHierarchy,
                 partContext, state
         ).generate()

compiler/backend/src/org/jetbrains/kotlin/codegen/PackageCodegenImpl.java

@@ -20,6 +20,7 @@ import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.progress.ProcessCanceledException;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.util.SmartList;
+import kotlin.text.StringsKt;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.codegen.context.PackageContext;
@@ -125,7 +126,7 @@ public class PackageCodegenImpl implements PackageCodegen {
         if (!generatePackagePart || !state.getGenerateDeclaredClassFilter().shouldGeneratePackagePart(file)) return;
 
         String name = fileClassType.getInternalName();
-        packagePartRegistry.addPart(name.substring(name.lastIndexOf('/') + 1));
+        packagePartRegistry.addPart(StringsKt.substringAfterLast(name, '/', name), null);
 
         ClassBuilder builder = state.getFactory().newVisitor(JvmDeclarationOriginKt.PackagePart(file, packageFragment), fileClassType, file);
 

compiler/backend/src/org/jetbrains/kotlin/codegen/PackagePartRegistry.kt

@@ -17,5 +17,5 @@
 package org.jetbrains.kotlin.codegen
 
 interface PackagePartRegistry {
-    fun addPart(partShortName: String)
+    fun addPart(partShortName: String, facadeShortName: String?)
 }