Tweak public APIs and use them in patch_sdk, dart2js, and kernel-service

utils/kernel-service/kernel-service.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /// This is an interface to the Dart Kernel parser and Kernel binary generator.
 ///
 /// It is used by the kernel-isolate to load Dart source code and generate
 /// Kernel binary format.
 ///
 /// This is either invoked as the root script of the Kernel isolate when used
 /// as a part of
 ///
 ///         dart --dfe=utils/kernel-service/kernel-service.dart ...
 ///
 /// invocation or it is invoked as a standalone script to perform training for
 /// the app-jit snapshot
 ///
 ///         dart utils/kernel-service/kernel-service.dart --train <source-file>
 ///
 ///
 library runtime.tools.kernel_service;
 
-import 'dart:async';
-import 'dart:io' hide FileSystemEntity;
+import 'dart:async' show Future;
+import 'dart:io' show File, Platform hide FileSystemEntity;
 import 'dart:isolate';
+import 'dart:typed_data' show Uint8List;
 
 import 'package:front_end/file_system.dart';
+import 'package:front_end/front_end.dart';
 import 'package:front_end/memory_file_system.dart';
 import 'package:front_end/physical_file_system.dart';
-import 'package:front_end/src/fasta/vm.dart'
-    show CompilationResult, Status, parseScriptInFileSystem;
+import 'package:front_end/src/fasta/kernel/utils.dart';
 import 'package:front_end/src/testing/hybrid_file_system.dart';
+import 'package:kernel/kernel.dart' show Program;
+import 'package:kernel/target/targets.dart' show TargetFlags;
+import 'package:kernel/target/vm_fasta.dart' show VmFastaTarget;
 
 const bool verbose = const bool.fromEnvironment('DFE_VERBOSE');
 
 const bool strongMode = const bool.fromEnvironment('DFE_STRONG_MODE');
 
+/// CODE REVIEW NOTE: this came from fasta.dart, moved here because it is
+/// specific to the kernel-service and nothing else.

[ahe, 2017/07/06 13:12:22]

I'm not at all excited about moving stuff from pkg/front_end to here.

[Siggi Cherem (dart-lang), 2017/07/06 19:05:28]

I hear you. Given that the code below is modified to use the public API (and not
internal fasta APIs), I feel the code is much smaller and simpler than it used
to be. I still would like to simplify it further. For example, I think it will
once we add the logic for discovering .packages in front_end directly.

[ahe, 2017/07/11 09:34:26]

We need to do something about this. This is way too much logic to have living
outside clear ownership.

I had the same complaint when you deleted code from fasta/testing, and it led to
problems, and you undid in this CL. I think this will lead to problems as well.

+Future<CompilationResult> _parseScriptInFileSystem(
+    Uri script, FileSystem fileSystem,
+    {bool verbose: false, bool strongMode: false}) async {
+  final Uri packagesUri = (Platform.packageConfig != null)
+      ? Uri.parse(Platform.packageConfig)
+      : await _findPackagesFile(fileSystem, script);
+  if (packagesUri == null) {
+    throw "Could not find .packages";
+  }
+
+  final Uri patchedSdk = Uri.base
+      .resolveUri(new Uri.file(Platform.resolvedExecutable))
+      .resolveUri(new Uri.directory("patched_sdk"));
+
+  if (verbose) {
+    print("""DFE: Requesting compilation {
+  scriptUri: ${script}
+  packagesUri: ${packagesUri}
+  patchedSdk: ${patchedSdk}
+}""");
+  }
+
+  try {
+    var errors = <String>[];
+    var options = new CompilerOptions()
+      ..strongMode = strongMode
+      ..fileSystem = fileSystem
+      ..target = new VmFastaTarget(new TargetFlags(strongMode: strongMode))
+      ..packagesFileUri = packagesUri
+      // TODO(sigmund): use outline.dill when the mixin transformer is modular.
+      ..sdkSummary = patchedSdk.resolve('platform.dill')
+      ..verbose = verbose
+      ..onError = (CompilationError e) => errors.add(e.message);
+
+    Program program = await kernelForProgram(script, options);
+    if (errors.isNotEmpty) return new CompilationResult.errors(errors);
+
+    // We serialize the program excluding platform.dill because the VM has these
+    // sources built-in. Everything loaded as a summary in [kernelForProgram] is
+    // marked `external`, so we can use that bit to decide what to excluce.
+    return new CompilationResult.ok(
+
+        /// CODE REVIEW NOTE: this is a change: we used to call the
+        /// LibraryFilteringBinaryBuilder. [serializeProgram] uses
+        /// LimitedBinaryBuilder instead (which not only excludes code, but also
+        /// string tables from excluded libraries).
+        serializeProgram(program, filter: (lib) => !lib.isExternal));
+  } catch (err, stack) {
+    return new CompilationResult.crash(err, stack);
+  }
+}
+
+/// This duplicates functionality from the Loader which we can't easily
+/// access from here.
+// TODO(sigmund): delete, this should be supported by the default options in
+// package:front_end.
+Future<Uri> _findPackagesFile(FileSystem fileSystem, Uri base) async {
+  var dir = new File.fromUri(base).parent;
+  while (true) {
+    final packagesFile = dir.uri.resolve(".packages");
+    if (await fileSystem.entityForUri(packagesFile).exists()) {
+      return packagesFile;
+    }
+    if (dir.parent.path == dir.path) {
+      break;
+    }
+    dir = dir.parent;
+  }
+  return null;
+}
+
 Future<CompilationResult> _processLoadRequestImpl(
     String inputFilePathOrUri, FileSystem fileSystem) {
   Uri scriptUri = Uri.parse(inputFilePathOrUri);
 
   // Because we serve both Loader and bootstrapping requests we need to
   // duplicate the logic from _resolveScriptUri(...) here and attempt to
   // resolve schemaless uris using current working directory.
   if (!scriptUri.hasScheme) {
     // Script does not have a scheme, assume that it is a path,
     // resolve it against the working directory.
     scriptUri = Uri.base.resolveUri(new Uri.file(inputFilePathOrUri));
   }
 
   if (!scriptUri.isScheme('file')) {
     // TODO(vegorov): Reuse loader code to support other schemes.
-    return new Future<CompilationResult>.value(new CompilationResult.error(
-        "Expected 'file' scheme for a script uri: got ${scriptUri.scheme}"));
+    return new Future<CompilationResult>.value(new CompilationResult.errors(
+        ["Expected 'file' scheme for a script uri: got ${scriptUri.scheme}"]));
   }
-  return parseScriptInFileSystem(scriptUri, fileSystem,
+  return _parseScriptInFileSystem(scriptUri, fileSystem,
       verbose: verbose, strongMode: strongMode);
 }
 
 // Process a request from the runtime. See KernelIsolate::CompileToKernel in
 // kernel_isolate.cc and Loader::SendKernelRequest in loader.cc.
 Future _processLoadRequest(request) async {
   if (verbose) {
     print("DFE: request: $request");
     print("DFE: Platform.packageConfig: ${Platform.packageConfig}");
     print("DFE: Platform.resolvedExecutable: ${Platform.resolvedExecutable}");
@@ skipping 72 matching lines @@
 main([args]) {
   if (args?.length == 2 && args[0] == '--train') {
     // This entry point is used when creating an app snapshot. The argument
     // provides a script to compile to warm-up generated code.
     train(args[1]);
   } else {
     // Entry point for the Kernel isolate.
     return new RawReceivePort()..handler = _processLoadRequest;
   }
 }
+
+/// CODE REVIEW NOTE: this came from fasta/vm.dart, also moved here because it
+/// is specific to the kernel-service and nothing else.
+
+/// Compilation status codes.
+///
+/// Note: The [index] property of these constants must match
+/// `Dart_KernelCompilationStatus` in
+/// [dart_api.h](../../../../runtime/include/dart_api.h).
+enum Status {
+  /// Compilation was successful.
+  ok,
+
+  /// Compilation failed with a compile time error.
+  error,
+
+  /// Compiler crashed.
+  crash,
+}
+
+abstract class CompilationResult {
+  CompilationResult._();
+
+  factory CompilationResult.ok(Uint8List bytes) = _CompilationOk;
+
+  factory CompilationResult.errors(List<String> errors) = _CompilationError;
+
+  factory CompilationResult.crash(Object exception, StackTrace stack) =
+      _CompilationCrash;
+
+  Status get status;
+
+  get payload;
+
+  List toResponse() => [status.index, payload];
+}
+
+class _CompilationOk extends CompilationResult {
+  final Uint8List bytes;
+
+  _CompilationOk(this.bytes) : super._();
+
+  @override
+  Status get status => Status.ok;
+
+  @override
+  get payload => bytes;
+
+  String toString() => "_CompilationOk(${bytes.length} bytes)";
+}
+
+abstract class _CompilationFail extends CompilationResult {
+  _CompilationFail() : super._();
+
+  String get errorString;
+
+  @override
+  get payload => errorString;
+}
+
+class _CompilationError extends _CompilationFail {
+  final List<String> errors;
+
+  _CompilationError(this.errors);
+
+  @override
+  Status get status => Status.error;
+
+  @override
+  String get errorString => errors.take(10).join('\n');
+
+  String toString() => "_CompilationError(${errorString})";
+}
+
+class _CompilationCrash extends _CompilationFail {
+  final Object exception;
+  final StackTrace stack;
+
+  _CompilationCrash(this.exception, this.stack);
+
+  @override
+  Status get status => Status.crash;
+
+  @override
+  String get errorString => "${exception}\n${stack}";
+
+  String toString() => "_CompilationCrash(${errorString})";
+}