v8/test/mjsunit/harmony/instanceof-es6.js
bmeurer 551e0aa11b [es6] Reintroduce the instanceof operator in the backends.
This adds back the instanceof operator support in the backends and
introduces a @@hasInstance protector cell on the isolate that guards the
fast path for the InstanceOfStub. This way we recover the ~10%
regression on Octane EarleyBoyer in Crankshaft and greatly improve
TurboFan and Ignition performance of instanceof.

R=ishell@chromium.org
TBR=hpayer@chromium.org,rossberg@chromium.org
BUG=chromium:597249, v8:4447
LOG=n

Review-Url: https://codereview.chromium.org/1980483003
Cr-Commit-Position: refs/heads/master@{#36275}
2016-05-17 11:25:59 +00:00

70 lines
2.1 KiB
JavaScript

// Copyright 2016 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.
// Flags: --harmony-instanceof
// Make sure it's an error if @@hasInstance isn't a function.
(function() {
var F = {};
F[Symbol.hasInstance] = null;
assertThrows(function() { 0 instanceof F; }, TypeError);
})();
// Make sure the result is coerced to boolean.
(function() {
var F = {};
F[Symbol.hasInstance] = function() { return undefined; };
assertEquals(0 instanceof F, false);
F[Symbol.hasInstance] = function() { return null; };
assertEquals(0 instanceof F, false);
F[Symbol.hasInstance] = function() { return true; };
assertEquals(0 instanceof F, true);
})();
// Make sure if @@hasInstance throws, we catch it.
(function() {
var F = {};
F[Symbol.hasInstance] = function() { throw new Error("always throws"); }
try {
0 instanceof F;
} catch (e) {
assertEquals(e.message, "always throws");
}
})();
// @@hasInstance works for bound functions.
(function() {
var BC = function() {};
var bc = new BC();
var bound = BC.bind();
assertEquals(bound[Symbol.hasInstance](bc), true);
assertEquals(bound[Symbol.hasInstance]([]), false);
})();
// if OrdinaryHasInstance is passed a non-callable receiver, return false.
assertEquals(Function.prototype[Symbol.hasInstance].call(Array, []), true);
assertEquals(Function.prototype[Symbol.hasInstance].call({}, {}), false);
// OrdinaryHasInstance passed a non-object argument returns false.
assertEquals(Function.prototype[Symbol.hasInstance].call(Array, 0), false);
// Cannot assign to @@hasInstance with %FunctionPrototype%.
(function() {
"use strict";
function F() {}
assertThrows(function() { F[Symbol.hasInstance] = (v) => v }, TypeError);
})();
// Check correct invocation of @@hasInstance handler on function instance.
(function() {
function F() {}
var counter = 0;
var proto = Object.getPrototypeOf(F);
Object.setPrototypeOf(F, null);
F[Symbol.hasInstance] = function(v) { ++counter; return true };
Object.setPrototypeOf(F, proto);
assertTrue(1 instanceof F);
assertEquals(1, counter);
})();