v8/test/mjsunit/regress/regress-5691.js
Sathya Gunasekaran 0f6eafe855 [promise] Remove incorrect fast path
Previously we would directly take the result from a fulfilled native
promise bypassing the microtask queue. This is observably different
from the spec.

Note: Our variant of the bluebird benchmark is heavily favored towards
fulfilled native promises because we don't use setTimeout (unlike the
original benchmark). I suspect this pattern doesn't appear often in
the wild so it's fine to take this hit for now.

PSA for Perf sheriffs: this is going to tank some benchmarks.

Bug: chromium:800651, v8:5691, v8:6007
Change-Id: Ic273bf2195529424b0d87359d28d5267060d5252
Reviewed-on: https://chromium-review.googlesource.com/895416
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51010}
2018-01-31 19:19:56 +00:00

24 lines
837 B
JavaScript

// Copyright 2018 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: --allow-natives-syntax
var log = "";
var result;
Promise.resolve()
.then(() => log += "|turn1")
.then(() => log += "|turn2")
.then(() => log += "|turn3")
.then(() => log += "|turn4")
.then(() => result = "|start|turn1|fast-resolve|turn2|turn3|slow-resolve|turn4\n"+log)
.catch(e => print("ERROR", e));
Promise.resolve(Promise.resolve()).then(() => log += "|fast-resolve");
(class extends Promise {}).resolve(Promise.resolve()).then(() => log += "|slow-resolve");
log += "|start";
%RunMicrotasks();
assertEquals("|start|turn1|fast-resolve|turn2|turn3|slow-resolve|turn4\n\
|start|turn1|fast-resolve|turn2|turn3|slow-resolve|turn4", result);