1 files changed, 109 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/arguments/args-exists.js b/js/src/jit-test/tests/arguments/args-exists.js
new file mode 100644
index 0000000000..35ea8e20bb
--- /dev/null
+++ b/js/src/jit-test/tests/arguments/args-exists.js
@@ -0,0 +1,109 @@
+// Test |in| operator on arguments objects.
+
+function testBasic() {
+  function arg0() { return 0 in arguments; }
+  function arg1() { return 1 in arguments; }
+  function arg100() { return 100 in arguments; }
+  function argn1() { return -1 in arguments; }
+  function argv(i) { return i in arguments; }
+
+  for (let i = 0; i < 100; ++i) {
+    assertEq(arg0(), false);
+    assertEq(arg0(1), true);
+    assertEq(arg0(1, 2), true);
+    assertEq(arg0(1, 2, 3), true);
+    assertEq(arg0(1, 2, 3, 4), true);
+    assertEq(arg0(1, 2, 3, 4, 5), true);
+
+    assertEq(arg1(), false);
+    assertEq(arg1(1), false);
+    assertEq(arg1(1, 2), true);
+    assertEq(arg1(1, 2, 3), true);
+    assertEq(arg1(1, 2, 3, 4), true);
+    assertEq(arg1(1, 2, 3, 4, 5), true);
+
+    assertEq(arg100(), false);
+    assertEq(arg100(1), false);
+    assertEq(arg100(1, 2), false);
+    assertEq(arg100(1, 2, 3), false);
+    assertEq(arg100(1, 2, 3, 4), false);
+    assertEq(arg100(1, 2, 3, 4, 5), false);
+
+    assertEq(argn1(), false);
+    assertEq(argn1(1), false);
+    assertEq(argn1(1, 2), false);
+    assertEq(argn1(1, 2, 3), false);
+    assertEq(argn1(1, 2, 3, 4), false);
+    assertEq(argn1(1, 2, 3, 4, 5), false);
+
+    assertEq(argv(i & 3), (i&3) <= 0);
+    assertEq(argv(i & 3, 1), (i&3) <= 1);
+    assertEq(argv(i & 3, 1, 2), (i&3) <= 2);
+    assertEq(argv(i & 3, 1, 2, 3), true);
+    assertEq(argv(i & 3, 1, 2, 3, 4), true);
+    assertEq(argv(i & 3, 1, 2, 3, 4, 5), true);
+  }
+}
+testBasic();
+
+// Modifying |arguments.length| doesn't change the result.
+function testOverriddenLength() {
+  function f(i) {
+    if (i === 100) {
+      arguments.length = 100;
+    }
+    return 1 in arguments;
+  }
+
+  for (let i = 0; i <= 150; ++i) {
+    assertEq(f(i), false);
+  }
+}
+testOverriddenLength();
+
+// Overridden elements are correctly detected.
+function testOverriddenElement() {
+  function f(i) {
+    if (i === 100) {
+      arguments[1] = 0;
+    }
+    return 1 in arguments;
+  }
+
+  for (let i = 0; i <= 150; ++i) {
+    assertEq(f(i), i === 100);
+  }
+}
+testOverriddenElement();
+
+// Deleted elements are correctly detected.
+function testDeletedElement() {
+  function f(i) {
+    if (i === 100) {
+      delete arguments[0];
+    }
+    return 0 in arguments;
+  }
+
+  for (let i = 0; i <= 150; ++i) {
+    assertEq(f(i), i !== 100);
+  }
+}
+testDeletedElement();
+
+// Contrary to most other arguments object optimisations, forwarded arguments
+// don't inhibit optimising the |in| operator.
+function testForwardedArg() {
+  function f(i) {
+    function closedOver() {
+      if (i === 100) i = 0;
+    }
+    closedOver();
+    return 0 in arguments;
+  }
+
+  for (let i = 0; i <= 150; ++i) {
+    assertEq(f(i), true);
+  }
+}
+testForwardedArg();