We did a row of smaller changes to adlc to improve its usability, e.g.

- Make adlc more stable, especially if parsing faulty .ad files.
- In some cases raise syntax errors instead of asserting.
- Write more comments into generated files and beautify format.
- Make calls to node->format() more stable.
- Clean up adlc code: warnings, dead code etc.

Notice that all these changes shouldn't affect the generated code in any way!

I collected all these and put them into this webrev:

 http://cr.openjdk.java.net/~goetz/webrevs/webrev-adlc_usability/

We would like to contribute this to the openJDK.  Could somebody
please review the change and push it if it seems useful to you?

Thanks a lot,
  Goetz.