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

pkg/front_end/lib/src/testing/compiler_common.dart

Index: pkg/front_end/lib/src/testing/compiler_common.dart
diff --git a/pkg/front_end/lib/src/testing/compiler_common.dart b/pkg/front_end/lib/src/testing/compiler_common.dart
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+++ b/pkg/front_end/lib/src/testing/compiler_common.dart
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+// Copyright (c) 2017, 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.
+
+/// Common compiler options and helper functions used for testing.
+library front_end.testing.compiler_options_common;
+
+import 'dart:async';
+
+import 'package:front_end/front_end.dart';
+import 'package:front_end/memory_file_system.dart';
+import 'package:front_end/src/fasta/testing/patched_sdk_location.dart';
+import 'package:front_end/src/testing/hybrid_file_system.dart';
+import 'package:kernel/ast.dart';
+
+/// Generate kernel for a script.
+///
+/// [scriptOrSources] can be a String, in which case it is the script to be
+/// compiled, or a Map containing source files. In which case, this function
+/// compiles the entry whose name is [fileName].
+///
+/// Wraps [kernelForProgram] with some default testing options (see [setup]).
+Future<Program> compileScript(dynamic scriptOrSources,
+    {fileName: 'main.dart',
+    List<String> inputSummaries: const [],
+    List<String> linkedDependencies: const [],
+    CompilerOptions options}) async {
+  options ??= new CompilerOptions();
+  Map<String, dynamic> sources;
+  if (scriptOrSources is String) {
+    sources = {fileName: scriptOrSources};
+  } else {
+    assert(scriptOrSources is Map);
+    sources = scriptOrSources;
+  }
+  await setup(options, sources,
+      inputSummaries: inputSummaries, linkedDependencies: linkedDependencies);
+  return await kernelForProgram(toTestUri(fileName), options);
+}
+
+/// Generate a program for a modular complation unit.
+///
+/// Wraps [kernelForBuildUnit] with some default testing options (see [setup]).
+Future<Program> compileUnit(List<String> inputs, Map<String, dynamic> sources,
+    {List<String> inputSummaries: const [],
+    List<String> linkedDependencies: const [],
+    CompilerOptions options}) async {
+  options ??= new CompilerOptions();
+  await setup(options, sources,
+      inputSummaries: inputSummaries, linkedDependencies: linkedDependencies);
+  return await kernelForBuildUnit(inputs.map(toTestUri).toList(), options);
+}
+
+/// Generate a summary for a modular complation unit.
+///
+/// Wraps [summaryFor] with some default testing options (see [setup]).
+Future<List<int>> summarize(List<String> inputs, Map<String, dynamic> sources,
+    {List<String> inputSummaries: const [], CompilerOptions options}) async {
+  options ??= new CompilerOptions();
+  await setup(options, sources, inputSummaries: inputSummaries);
+  return await summaryFor(inputs.map(toTestUri).toList(), options);
+}
+
+/// Defines a default set of options for testing:
+///
+///   * create a hybrid file system that stores [sources] in memory but allows
+///   access to the physical file system to load the SDK. [sources] can
+///   contain either source files (value is [String]) or .dill files (value
+///   is [List<int>]).
+///
+///   * define an empty .packages file
+///
+///   * specify the location of the sdk and sdk summaries based on
+///     the path where the `patched_sdk` is generated in the sdk-repo.
+Future<Null> setup(CompilerOptions options, Map<String, dynamic> sources,
+    {List<String> inputSummaries: const [],
+    List<String> linkedDependencies: const []}) async {
+  var fs = new MemoryFileSystem(_defaultDir);
+  sources.forEach((name, data) {
+    var entity = fs.entityForUri(toTestUri(name));
+    if (data is String) {
+      entity.writeAsStringSync(data);
+    } else {
+      entity.writeAsBytesSync(data);
+    }
+  });
+  fs.entityForUri(toTestUri('.packages')).writeAsStringSync('');
+  options
+    ..verify = true
+    ..fileSystem = new HybridFileSystem(fs)
+    ..inputSummaries = inputSummaries.map(toTestUri).toList()
+    ..linkedDependencies = linkedDependencies.map(toTestUri).toList()
+    ..packagesFileUri = toTestUri('.packages');
+
+  if (options.sdkSummary == null) {
+    options.sdkRoot = await computePatchedSdk();
+  }
+}
+
+/// A fake absolute directory used as the root of a memory-file system in the
+/// helpers above.
+Uri _defaultDir = Uri.parse('file:///a/b/c/');
+
+/// Convert relative file paths into an absolute Uri as expected by the test
+/// helpers above.
+Uri toTestUri(String relativePath) => _defaultDir.resolve(relativePath);
+
+/// A map defining the location of core libraries that purposely provides
+/// invalid Uris. Used by tests that want to ensure that the sdk libraries are
+/// not loaded from sources, but read from a .dill file.
+Map<String, Uri> invalidCoreLibs = {
+  'core': Uri.parse('file:///non_existing_file/core.dart'),
+  'async': Uri.parse('file:///non_existing_file/async.dart'),
+};
+
+bool isDartCoreLibrary(Library lib) => isDartCore(lib.importUri);
+bool isDartCore(Uri uri) => uri.scheme == 'dart' && uri.path == 'core';
+
+/// Find a library in [program] whose Uri ends with the given [suffix]
+Library findLibrary(Program program, String suffix) {
+  return program.libraries
+      .firstWhere((lib) => lib.importUri.path.endsWith(suffix));
+}