Refactor mjsunit/fuzz-natives-* into a separate test suite.

test/fuzz-natives/base.js

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+var RUN_WITH_ALL_ARGUMENT_ENTRIES = false;
+var kOnManyArgumentsRemove = 5;
+
+function makeArguments() {
+  var result = [ ];
+  result.push(17);
+  result.push(-31);
+  result.push(new Array(100));
+  result.push(new Array(100003));
+  result.push(Number.MIN_VALUE);
+  result.push("whoops");
+  result.push("x");
+  result.push({"x": 1, "y": 2});
+  var slowCaseObj = {"a": 3, "b": 4, "c": 5};
+  delete slowCaseObj.c;
+  result.push(slowCaseObj);
+  result.push(function () { return 8; });
+  return result;
+}
+
+var kArgObjects = makeArguments().length;
+
+function makeFunction(name, argc) {
+  var args = [];
+  for (var i = 0; i < argc; i++)
+    args.push("x" + i);
+  var argsStr = args.join(", ");
+  return new Function(args.join(", "),

[Michael Achenbach, 2014/04/29 15:51:53]

args.join(", ") == argsStr

[Jakob Kummerow, 2014/04/30 13:46:12]

Done.

+                      "return %" + name + "(" + argsStr + ");");
+}
+
+function testArgumentCount(name, argc) {
+  for (var i = 0; i < 10; i++) {

[Michael Achenbach, 2014/04/29 15:51:53]

Should we not better just loop until argc + 1?

+    var func = null;
+    try {
+      func = makeFunction(name, i);
+    } catch (e) {
+      if (e != "SyntaxError: Illegal access") throw e;
+    }
+    if (func === null && i == argc) {
+      throw "unexpected exception";

[Michael Achenbach, 2014/04/29 15:51:53]

Could we not already "continue" in all other cases where func === null?

+    }
+    var args = [ ];
+    for (var j = 0; j < i; j++)
+      args.push(0);
+    try {
+      func.apply(void 0, args);
+    } catch (e) {
+      // we don't care what happens as long as we don't crash
+    }
+  }
+}
+
+function testArgumentTypes(name, argc) {
+  var type = 0;
+  var hasMore = true;
+  var func = makeFunction(name, argc);
+  while (hasMore) {
+    var argPool = makeArguments();
+    // When we have 5 or more arguments we lower the amount of tests cases

[Michael Achenbach, 2014/04/29 15:51:53]

...which is always the case.

+    // by randomly removing kOnManyArgumentsRemove entries

[Michael Achenbach, 2014/04/29 15:51:53]

Wouldn't it be better to always choose, 5 instead of removing 5 of 10? In case
somebody extends the list at some point...

+    var numArguments = RUN_WITH_ALL_ARGUMENT_ENTRIES ?
+      kArgObjects : kArgObjects-kOnManyArgumentsRemove;

[Michael Achenbach, 2014/04/29 15:51:53]

nit: space around -

[Jakob Kummerow, 2014/04/30 13:46:12]

Done.

+    if (kArgObjects >= 5 && !RUN_WITH_ALL_ARGUMENT_ENTRIES) {
+      for (var i = 0; i < kOnManyArgumentsRemove; i++) {
+        var rand = Math.floor(Math.random() * (kArgObjects - i));

[Michael Achenbach, 2014/04/29 15:51:53]

Might be easier readable when calling repeatedly argPool.length instead of
(kArgObjects - i)

+        argPool.splice(rand,1);
+      }
+    }
+    var current = type;
+    var hasMore = false;

[Michael Achenbach, 2014/04/29 15:51:53]

var hasMore exists in the outer scope. Remove var?

[Jakob Kummerow, 2014/04/30 13:46:12]

Done.

+    var argList = [ ];
+    for (var i = 0; i < argc; i++) {

[Michael Achenbach, 2014/04/29 15:51:53]

Maybe add a TODO about improving the complexity, so that it doesn't depend
anymore on argc or does some other kind of combination like all-pairs testing...

+      var index = current % numArguments;
+      current = (current / numArguments) << 0;
+      if (index != (numArguments - 1))
+        hasMore = true;
+      argList.push(argPool[index]);
+    }
+    try {
+      func.apply(void 0, argList);
+    } catch (e) {
+      // we don't care what happens as long as we don't crash
+    }
+    type++;
+  }
+}
+
+testArgumentCount(NAME, ARGC);
+testArgumentTypes(NAME, ARGC);