Associate partial source map with each code block in Universe.generatedCode.

lib/compiler/implementation/dart2js.dart

 // Copyright (c) 2012, 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');
 
 #import('dart:io');
 #import('dart:uri');
 #import('dart:utf');
 
@@ skipping 224 matching lines @@
   info('compiling $uri');
   info('package root is $packageRoot');
 
   // TODO(ahe): We expect the future to be complete and call value
   // directly. In effect, we don't support truly asynchronous API.
   String code = api.compile(uri, libraryRoot, packageRoot, provider, handler,
                             options).value;
   if (code === null) {
     fail('Error: Compilation failed.');
   }
-  code = '$code\n//@ sourceMappingURL=${relativize(out, sourceMapOut)}';

[ahe, 2012/08/02 20:34:56]

Doesn't this mean that we ignore source maps?

[podivilov, 2012/08/21 12:29:35]

I think dart2js shouldn't inject sourceMappingURL comment into compiled code.
You may want to use X-SourceMap http header to link compiled code to source map.
And it is easier to append new sourceMappingURL comment than fixing existing one
in case the relative path changed or you want to use absolute paths for source
maps on your server.

[ahe, 2012/08/21 12:42:32]

How do we enable source maps by default without having a special HTTP server?

[podivilov, 2012/08/21 17:04:25]

Should we enable them by default? One can easily append the comment as a
deployment step if needed.

[ahe, 2012/08/22 09:39:43]

I think the default behavior should be to enable source maps by default. We can
later consider if there should be an option to not enable them.

   writeString(out, code);
   int jsBytesWritten = code.length;
   info('compiled $dartBytesRead bytes Dart -> $jsBytesWritten bytes JS '
        'in ${relativize(cwd, out)}');
   if (!explicitOut) {
     String input = uriPathToNative(arguments[0]);
     String output = relativize(cwd, out);
     print('Dart file $input compiled to JavaScript: $output');
   }
 }
@@ skipping 118 matching lines @@
     } catch (var ignored) {
       print('Internal error: error while printing exception');
     }
     try {
       print(trace);
     } finally {
       exit(253); // 253 is recognized as a crash by our test scripts.
     }
   }
 }