driver.js

function start(glob)
{
  var fuzzSeed = Math.floor(Math.random() * Math.pow(2,28));
  dumpln("fuzzSeed: " + fuzzSeed);
  Random.init(fuzzSeed);

  // Split this string across two source strings to ensure that if a
  // generated function manages to output the entire jsfunfuzz source,
  // that output won't match the grep command.
  var cookie = "/*F";
  cookie += "RC*/";

  // Can be set to true if makeStatement has side effects, such as crashing, so you have to reduce "the hard way".
  var dumpEachSeed = false;

  if (dumpEachSeed) {
    dumpln(cookie + "Random.init(0);");
  }

  mathInitFCM();

  count = 0;

  if (jsshell) {
    // If another script specified a "maxRunTime" argument, use it; otherwise, run forever
    var MAX_TOTAL_TIME = (glob.maxRunTime) || (Infinity);
    var startTime = new Date();
    var lastTime;

    do {
      testOne();
      var elapsed1 = new Date() - lastTime;
      if (elapsed1 > 1000) {
        print("That took " + elapsed1 + "ms!");
      }
      lastTime = new Date();
    } while(lastTime - startTime < MAX_TOTAL_TIME);
  } else {
    setTimeout(testStuffForAWhile, 200);
  }

  function testStuffForAWhile()
  {
    for (var j = 0; j < 100; ++j)
      testOne();

    if (count % 10000 < 100)
      printImportant("Iterations: " + count);

    setTimeout(testStuffForAWhile, 30);
  }

  function testOne()
  {
    ++count;

    // Sometimes it makes sense to start with simpler functions:
    //var depth = ((count / 1000) | 0) & 16;
    var depth = 14;

    if (dumpEachSeed) {
      // More complicated, but results in a much shorter script, making SpiderMonkey happier.
      var MTA = uneval(Random.twister.export_mta());
      var MTI = Random.twister.export_mti();
      if (MTA != Random.lastDumpedMTA) {
        dumpln(cookie + "Random.twister.import_mta(" + MTA + ");");
        Random.lastDumpedMTA = MTA;
      }
      dumpln(cookie + "Random.twister.import_mti(" + MTI + "); void (makeScript(" + depth + "));");
    }

    var code = makeScript(depth);

    if (count == 1 && engine == ENGINE_SPIDERMONKEY_TRUNK && rnd(5)) {
      code = "tryRunning = useSpidermonkeyShellSandbox(" + rnd(4) + ");";
      //print("Sane mode!")
    }

  //  if (rnd(10) === 1) {
  //    var dp = "/*infloop-deParen*/" + Random.index(deParen(code));
  //    if (dp)
  //      code = dp;
  //  }
    dumpln(cookie + "count=" + count + "; tryItOut(" + uneval(code) + ");");

    tryItOut(code);
  }
}


function failsToCompileInTry(code) {
  // Why would this happen? One way is "let x, x"
  try {
    var codeInTry = "try { " + code + " } catch(e) { }";
    void new Function(codeInTry);
    return false;
  } catch(e) {
    return true;
  }
}