Implementation of async-await transformation on js ast.

pkg/compiler/lib/src/dart2js.dart

 // Copyright (c) 2013, 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.
 
 library dart2js.cmdline;
 
 import 'dart:async'
     show Future, EventSink;
 import 'dart:convert' show UTF8, LineSplitter;
 import 'dart:io'
@@ skipping 96 matching lines @@
   Uri sourceMapOut = currentDirectory.resolve('out.js.map');
   Uri packageRoot = null;
   List<String> options = new List<String>();
   bool explicitOut = false;
   bool wantHelp = false;
   bool wantVersion = false;
   String outputLanguage = 'JavaScript';
   bool stripArgumentSet = false;
   bool analyzeOnly = false;
   bool analyzeAll = false;
-  bool enableAsyncAwait = false;
   bool allowNativeExtensions = false;
   bool trustTypeAnnotations = false;
   bool trustPrimitives = false;
   bool checkedMode = false;
   // List of provided options that imply that output is expected.
   List<String> optionsImplyCompilation = <String>[];
   bool hasDisallowUnsafeEval = false;
   // TODO(johnniwinther): Measure time for reading files.
   SourceFileProvider inputProvider = new CompilerSourceFileProvider();
   diagnosticHandler = new FormattingDiagnosticHandler(inputProvider);
@@ skipping 57 matching lines @@
   setAnalyzeOnly(String argument) {
     analyzeOnly = true;
     passThrough(argument);
   }
 
   setAnalyzeAll(String argument) {
     analyzeAll = true;
     passThrough(argument);
   }
 
-  setEnableAsync(String argument) {
-    enableAsyncAwait = true;
-    passThrough(argument);
-  }
-
   setAllowNativeExtensions(String argument) {
     allowNativeExtensions = true;
     passThrough(argument);
   }
 
   setVerbose(_) {
     diagnosticHandler.verbose = true;
     passThrough('--verbose');
   }
 
@@ skipping 123 matching lines @@
     new OptionHandler('--categories=.*', setCategories),
     new OptionHandler('--disable-type-inference', implyCompilation),
     new OptionHandler('--terse', passThrough),
     new OptionHandler('--deferred-map=.+', implyCompilation),
     new OptionHandler('--dump-info', implyCompilation),
     new OptionHandler('--disallow-unsafe-eval',
                       (_) => hasDisallowUnsafeEval = true),
     new OptionHandler('--show-package-warnings', passThrough),
     new OptionHandler('--csp', passThrough),
     new OptionHandler('--enable-experimental-mirrors', passThrough),
-    new OptionHandler('--enable-async', setEnableAsync),
+    new OptionHandler('--enable-async', (_) {
+      diagnosticHandler.info(
+          "Option '--enable-async' is no longer needed. "
+          "Async-await is supported by default.",
+          api.Diagnostic.HINT);
+    }),
     new OptionHandler('--enable-enum', (_) {
       diagnosticHandler.info(
           "Option '--enable-enum' is no longer needed. "
           "Enums are supported by default.",
           api.Diagnostic.HINT);
     }),
     new OptionHandler('--allow-native-extensions', setAllowNativeExtensions),
     new OptionHandler('--generate-code-with-compile-time-errors', passThrough),
 
     // The following three options must come last.
@@ skipping 49 matching lines @@
           "Option '--analyze-all' implies '--analyze-only'.",
           api.Diagnostic.INFO);
     }
     diagnosticHandler.info(
         "Options $optionsImplyCompilation indicate that output is expected, "
         "but compilation is turned off by the option '--analyze-only'.",
         api.Diagnostic.INFO);
   }
   if (analyzeAll) analyzeOnly = true;
   if (!analyzeOnly) {
-    if (enableAsyncAwait && outputLanguage != OUTPUT_LANGUAGE_DART) {
-      helpAndFail("Option '--enable-async' is currently only supported in "
-                  "combination with the '--analyze-only' option.");
-    }
     if (allowNativeExtensions) {
       helpAndFail("Option '--allow-native-extensions' is only supported in "
                   "combination with the '--analyze-only' option.");
     }
   }
 
   diagnosticHandler.info('Package root is $packageRoot');
 
   options.add('--out=$out');
   options.add('--source-map=$sourceMapOut');
@@ skipping 295 matching lines @@
       } else if (exitCode == 253) {
         print(">>> TEST CRASH");
       } else {
         print(">>> TEST FAIL");
       }
       stderr.writeln(">>> EOF STDERR");
       subscription.resume();
     });
   });
 }