Implement source sections compiler plugin

allows to compile only parts of the source files, denoted by top-level
"sections" (function with lambda param calls), but preserving original
file line/column numbers for easier diagnostics. Allow e.g. to compile
gradle "buildscript" section without preprocessing original file in
advance. See tests for examples.

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/CompileEnvironmentUtil.java

@@ -41,6 +41,7 @@ import org.jetbrains.kotlin.cli.common.modules.ModuleScriptData;
 import org.jetbrains.kotlin.cli.common.modules.ModuleXmlParser;
 import org.jetbrains.kotlin.config.CompilerConfiguration;
 import org.jetbrains.kotlin.config.JVMConfigurationKeys;
+import org.jetbrains.kotlin.extensions.PreprocessedFileCreator;
 import org.jetbrains.kotlin.idea.KotlinFileType;
 import org.jetbrains.kotlin.name.FqName;
 import org.jetbrains.kotlin.psi.KtFile;
@@ -161,6 +162,8 @@ public class CompileEnvironmentUtil {
         final Set<VirtualFile> processedFiles = Sets.newHashSet();
         final List<KtFile> result = Lists.newArrayList();
 
+        final PreprocessedFileCreator virtualFileCreator = new PreprocessedFileCreator(project);
+
         for (String sourceRootPath : sourceRoots) {
             if (sourceRootPath == null) {
                 continue;
@@ -190,7 +193,8 @@ public class CompileEnvironmentUtil {
                 @Override
                 public Unit invoke(File file) {
                     if (file.isFile()) {
-                        VirtualFile virtualFile = localFileSystem.findFileByPath(file.getAbsolutePath());
+                        VirtualFile originalVirtualFile = localFileSystem.findFileByPath(file.getAbsolutePath());
+                        VirtualFile virtualFile = originalVirtualFile != null ? virtualFileCreator.create(originalVirtualFile) : null;
                         if (virtualFile != null && !processedFiles.contains(virtualFile)) {
                             processedFiles.add(virtualFile);
                             PsiFile psiFile = PsiManager.getInstance(project).findFile(virtualFile);

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

@@ -85,6 +85,7 @@ import org.jetbrains.kotlin.codegen.extensions.ExpressionCodegenExtension
 import org.jetbrains.kotlin.compiler.plugin.ComponentRegistrar
 import org.jetbrains.kotlin.config.*
 import org.jetbrains.kotlin.extensions.DeclarationAttributeAltererExtension
+import org.jetbrains.kotlin.extensions.PreprocessedVirtualFileFactoryExtension
 import org.jetbrains.kotlin.extensions.StorageComponentContainerContributor
 import org.jetbrains.kotlin.idea.KotlinFileType
 import org.jetbrains.kotlin.load.kotlin.KotlinBinaryClassCache
@@ -160,6 +161,7 @@ class KotlinCoreEnvironment private constructor(
         PackageFragmentProviderExtension.registerExtensionPoint(project)
         StorageComponentContainerContributor.registerExtensionPoint(project)
         DeclarationAttributeAltererExtension.registerExtensionPoint(project)
+        PreprocessedVirtualFileFactoryExtension.registerExtensionPoint(project)
 
         for (registrar in configuration.getList(ComponentRegistrar.PLUGIN_COMPONENT_REGISTRARS)) {
             registrar.registerProjectComponents(project, configuration)