Using the Mozilla source server

Using the Mozilla source server is now even more feature-packed. The nightly debug builds are now also Source Indexed so that by following a couple of simple steps you can also have the source code served to you for debugging without a local build

What you'll need

  • WinDbg or Visual Studio (Note: express editions will not work, but WinDbg is a free download)
  • A nightly build that was created after April 15, 2008; go to the /pub/firefox/nightly/latest-mozilla-central/ folder and grab the installer
  • For builds predating the switch to Mercurial, you'll need cvs.exe, added to your PATH (the cvs.exe from MozillaBuild has problems, use this one instead)
Note: Do not use the CVS from MozillaBuild, it will not work!

Set up symbols

Follow the instructions for Using the Mozilla symbol server. Once the symbol path is set you must now enable Source Server.

Using the source server in WinDbg

In the WinDbg command line, type .srcfix and hit enter. This enables source server support.


Now, when you click on a frame in the "Calls" window, WinDbg will prompt you about running cvs to download the associated source code.


If you click "Yes", WinDbg will display *BUSY* in the status bar while it downloads the source, and then it will automatically open the file and highlight the current line.


Using the source server in Visual Studio

Note: Source server support does not work correctly out of the box in Visual Studio 2005. If you install WinDBG, and copy srcsrv.dll from the WinDBG install dir to the Visual Studio install dir (replacing the existing copy) it will work.

Enable source server support under Tools -> Options. Also, disable (uncheck) the box that says "Require source files to exactly match the original version".


Start debugging your program. Symbols will load and then, if you're using a CVS build, when you try to step into or step over a confirmation window will appear asking if you trust the cvs command that Source Server is trying to run.


After the command executes, the source file will load in the window.