Introduce -Xoutput-imports mode of JVM compiler

In this mode, instead of analyzing files and generating bytecode for
them, compiler just saves imports of each file in JSON map of form

'<path to file> -> [<import1>, <import2>, ...]'

It is needed for some external tools, notably for Google3 toolchain.

compiler/cli/build.gradle.kts

@@ -20,6 +20,7 @@ dependencies {
     compile(project(":js:js.translator"))
     compile(project(":js:js.serializer"))
     compile(project(":js:js.dce"))
+    compile(commonDep("org.jetbrains.kotlinx", "kotlinx-serialization-runtime")) { isTransitive = false }
     compile(commonDep("org.fusesource.jansi", "jansi"))
     compile(commonDep("org.jline", "jline"))
     compile(files("${System.getProperty("java.home")}/../lib/tools.jar"))

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/K2JVMCompilerArguments.kt

@@ -225,6 +225,13 @@ class K2JVMCompilerArguments : CommonCompilerArguments() {
     )
     var noExceptionOnExplicitEqualsForBoxedNull by FreezableVar(false)
 
+    @Argument(
+        value = "-Xoutput-imports",
+        valueDescription = "<path>",
+        description = "Output imports from all compiled files to the specified file in JSON format"
+    )
+    var outputImports: String? by FreezableVar(null)
+
     @Argument(value = "-Xenable-jvm-default", description = "Allow to use '@JvmDefault' for JVM default method support")
     var enableJvmDefault: Boolean by FreezableVar(false)
 

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/K2JVMCompiler.kt

@@ -23,10 +23,7 @@ import org.jetbrains.kotlin.cli.common.ExitCode.*
 import org.jetbrains.kotlin.cli.common.arguments.K2JVMCompilerArguments
 import org.jetbrains.kotlin.cli.common.messages.*
 import org.jetbrains.kotlin.cli.common.messages.CompilerMessageSeverity.*
-import org.jetbrains.kotlin.cli.jvm.compiler.CompileEnvironmentUtil
-import org.jetbrains.kotlin.cli.jvm.compiler.EnvironmentConfigFiles
-import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment
-import org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler
+import org.jetbrains.kotlin.cli.jvm.compiler.*
 import org.jetbrains.kotlin.cli.jvm.config.JvmClasspathRoot
 import org.jetbrains.kotlin.cli.jvm.config.JvmModulePathRoot
 import org.jetbrains.kotlin.cli.jvm.config.addJavaSourceRoot
@@ -34,6 +31,7 @@ import org.jetbrains.kotlin.cli.jvm.modules.CoreJrtFileSystem
 import org.jetbrains.kotlin.cli.jvm.plugins.PluginCliParser
 import org.jetbrains.kotlin.cli.jvm.repl.ReplFromTerminal
 import org.jetbrains.kotlin.codegen.CompilationException
+import org.jetbrains.kotlin.compiler.plugin.ComponentRegistrar
 import org.jetbrains.kotlin.config.*
 import org.jetbrains.kotlin.incremental.components.ExpectActualTracker
 import org.jetbrains.kotlin.incremental.components.LookupTracker
@@ -378,6 +376,11 @@ class K2JVMCompiler : CLICompiler<K2JVMCompilerArguments>() {
             configuration.put(JVMConfigurationKeys.ADD_BUILT_INS_FROM_COMPILER_TO_DEPENDENCIES, arguments.addCompilerBuiltIns)
             configuration.put(JVMConfigurationKeys.CREATE_BUILT_INS_FROM_MODULE_DEPENDENCIES, arguments.loadBuiltInsFromDependencies)
 
+            if (arguments.outputImports != null) {
+                configuration.put(JVMConfigurationKeys.OUTPUT_IMPORTS, arguments.outputImports!!)
+                configuration.add(ComponentRegistrar.PLUGIN_COMPONENT_REGISTRARS, ImportsProducerComponentRegistrar())
+            }
+
             arguments.declarationsOutputPath?.let { configuration.put(JVMConfigurationKeys.DECLARATIONS_JSON_PATH, it) }
         }
 

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

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. 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.cli.jvm.compiler
+
+import com.intellij.mock.MockProject
+import com.intellij.openapi.project.Project
+import kotlinx.serialization.internal.StringSerializer
+import kotlinx.serialization.json.JSON
+import kotlinx.serialization.list
+import kotlinx.serialization.map
+import org.jetbrains.kotlin.analyzer.AnalysisResult
+import org.jetbrains.kotlin.compiler.plugin.ComponentRegistrar
+import org.jetbrains.kotlin.config.CompilerConfiguration
+import org.jetbrains.kotlin.config.JVMConfigurationKeys
+import org.jetbrains.kotlin.container.ComponentProvider
+import org.jetbrains.kotlin.context.ProjectContext
+import org.jetbrains.kotlin.descriptors.ModuleDescriptor
+import org.jetbrains.kotlin.psi.KtFile
+import org.jetbrains.kotlin.resolve.BindingTrace
+import org.jetbrains.kotlin.resolve.jvm.extensions.AnalysisHandlerExtension
+import java.io.File
+
+class ImportsProducerComponentRegistrar : ComponentRegistrar {
+    override fun registerProjectComponents(project: MockProject, configuration: CompilerConfiguration) {
+        val destinationPath = configuration[JVMConfigurationKeys.OUTPUT_IMPORTS] ?: return
+        AnalysisHandlerExtension.registerExtension(project, ImportsProducerExtension(destinationPath))
+    }
+}
+
+class ImportsProducerExtension(destinationPath: String) : AnalysisHandlerExtension {
+    private val destination: File = File(destinationPath)
+
+    override fun doAnalysis(
+        project: Project,
+        module: ModuleDescriptor,
+        projectContext: ProjectContext,
+        files: Collection<KtFile>,
+        bindingTrace: BindingTrace,
+        componentProvider: ComponentProvider
+    ): AnalysisResult? {
+        val filePathToImports: MutableMap<String, List<String>> = mutableMapOf()
+
+        for (file in files) {
+            filePathToImports[file.virtualFilePath] = file.importDirectives.map { it.text }
+        }
+
+        val serializer = (StringSerializer to StringSerializer.list).map
+
+        val jsonStringWithImports = JSON.stringify(serializer, filePathToImports)
+
+        destination.writeText(jsonStringWithImports)
+
+        return AnalysisResult.success(bindingTrace.bindingContext, module, shouldGenerateCode = false)
+    }
+}