push-densely-loopy-nonwritable-length.js

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// Force recognition of a known-constant.

var push = Array.prototype.push;

function f(arr)

  // Push an actual constant to trigger JIT-inlining of the effect of the push.

  push.call(arr, 99);

function basic(out)

  // Create an array of arrays, to be iterated over for [].push-calling.  We

  // can't just loop on push on a single array with non-writable length because

  // push throws when called on an array with non-writable length.

  var arrs = out.arrs = [];

  for (var i = 0; i < 100; i++)

    arrs.push([]);

  // Use a much-greater capacity than the eventual non-writable length.

  var a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15];

  Object.defineProperty(a, "length", { writable: false, value: 6 });

  arrs.push(a);

  for (var i = 0, sz = arrs.length; i < sz; i++)

    var arr = arrs[i];

    f(arr);

var obj = {};

var arrs, a;

try

  basic(obj);

  throw new Error("didn't throw!");

catch (e)

  assertEq(e instanceof TypeError, true, "expected TypeError, got " + e);

  arrs = obj.arrs;

  assertEq(arrs.length, 101);

  for (var i = 0; i < 100; i++)

    assertEq(arrs[i].length, 1, "unexpected length for arrs[" + i + "]");

    assertEq(arrs[i][0], 99, "bad element for arrs[" + i + "]");

  a = arrs[100];

  assertEq(a.hasOwnProperty(6), false);

  assertEq(a[6], undefined);

  assertEq(a.length, 6);