JVM: Add an extension point for file output

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

@@ -26,6 +26,7 @@ import org.jetbrains.annotations.Nullable;
 import org.jetbrains.annotations.TestOnly;
 import org.jetbrains.kotlin.backend.common.output.OutputFile;
 import org.jetbrains.kotlin.backend.common.output.OutputFileCollection;
+import org.jetbrains.kotlin.codegen.extensions.ClassFileFactoryFinalizerExtension;
 import org.jetbrains.kotlin.codegen.state.GenerationState;
 import org.jetbrains.kotlin.config.JvmAnalysisFlags;
 import org.jetbrains.kotlin.load.kotlin.ModuleMappingUtilKt;
@@ -50,6 +51,7 @@ import static org.jetbrains.kotlin.codegen.JvmCodegenUtil.getMappingFileName;
 public class ClassFileFactory implements OutputFileCollection {
     private final GenerationState state;
     private final ClassBuilderFactory builderFactory;
+    private final List<ClassFileFactoryFinalizerExtension> finalizers;
     private final Map<String, OutAndSourceFileList> generators = Collections.synchronizedMap(new LinkedHashMap<>());
 
     private boolean isDone = false;
@@ -57,9 +59,10 @@ public class ClassFileFactory implements OutputFileCollection {
     private final Set<File> sourceFiles = new HashSet<>();
     private final PackagePartRegistry packagePartRegistry = new PackagePartRegistry();
 
-    public ClassFileFactory(@NotNull GenerationState state, @NotNull ClassBuilderFactory builderFactory) {
+    public ClassFileFactory(@NotNull GenerationState state, @NotNull ClassBuilderFactory builderFactory, @NotNull List<ClassFileFactoryFinalizerExtension> finalizers) {
         this.state = state;
         this.builderFactory = builderFactory;
+        this.finalizers = finalizers;
     }
 
     public GenerationState getGenerationState() {
@@ -111,6 +114,9 @@ public class ClassFileFactory implements OutputFileCollection {
         if (!isDone) {
             isDone = true;
             writeModuleMappings();
+            for (ClassFileFactoryFinalizerExtension extension : finalizers) {
+                extension.finalizeClassFactory(this);
+            }
         }
     }
 

compiler/backend/src/org/jetbrains/kotlin/codegen/extensions/ClassFileFactoryFinalizerExtension.kt

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.codegen.extensions
+
+import org.jetbrains.kotlin.codegen.ClassFileFactory
+import org.jetbrains.kotlin.extensions.ProjectExtensionDescriptor
+
+/**
+ * Extension point which is called after the compiler outputs have been finalized,
+ * which allows inspecting all output files, except for jar manifests.
+ */
+interface ClassFileFactoryFinalizerExtension {
+    companion object : ProjectExtensionDescriptor<ClassFileFactoryFinalizerExtension>(
+        "org.jetbrains.kotlin.classFileFactoryFinalizerExtension", ClassFileFactoryFinalizerExtension::class.java)
+
+    fun finalizeClassFactory(factory: ClassFileFactory)
+}

compiler/backend/src/org/jetbrains/kotlin/codegen/state/GenerationState.kt

@@ -14,6 +14,7 @@ import org.jetbrains.kotlin.codegen.binding.CodegenBinding
 import org.jetbrains.kotlin.codegen.context.CodegenContext
 import org.jetbrains.kotlin.codegen.context.RootContext
 import org.jetbrains.kotlin.codegen.extensions.ClassBuilderInterceptorExtension
+import org.jetbrains.kotlin.codegen.extensions.ClassFileFactoryFinalizerExtension
 import org.jetbrains.kotlin.codegen.inline.GlobalInlineContext
 import org.jetbrains.kotlin.codegen.inline.InlineCache
 import org.jetbrains.kotlin.codegen.intrinsics.IntrinsicMethods
@@ -369,7 +370,8 @@ class GenerationState private constructor(
                 extension.interceptClassBuilderFactory(classBuilderFactory, originalFrontendBindingContext, diagnostics)
             }
 
-        this.factory = ClassFileFactory(this, interceptedBuilderFactory)
+        val finalizers = ClassFileFactoryFinalizerExtension.getInstances(project)
+        this.factory = ClassFileFactory(this, interceptedBuilderFactory, finalizers)
     }
 
     fun beforeCompile() {

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/KotlinCoreEnvironment.kt

@@ -76,6 +76,7 @@ import org.jetbrains.kotlin.cli.jvm.modules.CliJavaModuleFinder
 import org.jetbrains.kotlin.cli.jvm.modules.CliJavaModuleResolver
 import org.jetbrains.kotlin.cli.jvm.modules.CoreJrtFileSystem
 import org.jetbrains.kotlin.codegen.extensions.ClassBuilderInterceptorExtension
+import org.jetbrains.kotlin.codegen.extensions.ClassFileFactoryFinalizerExtension
 import org.jetbrains.kotlin.codegen.extensions.ExpressionCodegenExtension
 import org.jetbrains.kotlin.compiler.plugin.ComponentRegistrar
 import org.jetbrains.kotlin.config.*
@@ -641,6 +642,7 @@ class KotlinCoreEnvironment private constructor(
             SyntheticResolveExtension.registerExtensionPoint(project)
             SyntheticJavaResolveExtension.registerExtensionPoint(project)
             ClassBuilderInterceptorExtension.registerExtensionPoint(project)
+            ClassFileFactoryFinalizerExtension.registerExtensionPoint(project)
             AnalysisHandlerExtension.registerExtensionPoint(project)
             PackageFragmentProviderExtension.registerExtensionPoint(project)
             StorageComponentContainerContributor.registerExtensionPoint(project)