The Tor Browser / file revision

 // |jit-test|

 gczeal(4);

 var optionNames = options().split(',');

   for (var i = 0; i < optionNames.length; i++)

     var optionName = optionNames[i];

 evaluate("\

 function addDebug(g, id) {\

     var debuggerGlobal = newGlobal();\

     debuggerGlobal.debuggee = g;\

     debuggerGlobal.id = id;\

     debuggerGlobal.print = function (s) { (g) += s; };\

     debuggerGlobal.eval('var dbg = new Debugger(debuggee);dbg.onDebuggerStatement = function () { print(id); debugger; };');\

     return debuggerGlobal;\

 }\

 var base = newGlobal();\

 var top = base;\

 for (var i = 0; i < 8; i++ )\

     top = addDebug(top, i);\

 base.eval('debugger;');\

 ");