1f8dcc5d2e
The idea here is that in case the `thenable` is a JSPromise and `then` is the initial `Promise.prototype.then` method, and the @@species lookup chain is intact, we can skip creating the temporary promise and the closures (with the shared context), and instead directly call into our PerformPromiseThen. This is sound since - given above mentioned conditions - our short-cut PerformPromiseThen(thenable, undefined, undefined, promise_to_resolve) is not observably different from the actual resolve, reject = CreateResolvingFunctions(promise_to_resolve) result_capability = NewPromiseCapability(%Promise%) PerformPromiseThen(thenable, resolve, reject, result_capability) except through PromiseHooks (and potentially via the async stack traces). So we disable the fast-path if either promise hooks are enabled or the debugger is active for now. This improves the performance on the wikipedia benchmark by 20-25% and the bluebird-doxbee benchmark by around 20%. Bug: v8:7253 Change-Id: I23c92ad365c2b71d65057573f2d8febe2afe00b0 Reviewed-on: https://chromium-review.googlesource.com/911800 Commit-Queue: Benedikt Meurer <bmeurer@chromium.org> Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org> Cr-Commit-Position: refs/heads/master@{#51261}
128 lines
2.5 KiB
JavaScript
128 lines
2.5 KiB
JavaScript
// Copyright 2018 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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(function() {
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let resolve;
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let onFulfilledValue;
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const p = new Promise(r => resolve = r);
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resolve(Promise.resolve(1));
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p.then(
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v => {
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onFulfilledValue = v;
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},
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e => {
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assertUnreachable();
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});
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setTimeout(_ => assertEquals(1, onFulfilledValue));
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})();
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(function() {
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let resolve;
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let onRejectedReason;
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const p = new Promise(r => resolve = r);
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resolve(Promise.reject(1));
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p.then(
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v => {
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assertUnreachable();
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},
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e => {
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onRejectedReason = e;
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});
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setTimeout(_ => assertEquals(1, onRejectedReason));
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})();
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(function() {
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let onFulfilledValue;
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(async () => Promise.resolve(1))().then(
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v => {
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onFulfilledValue = v;
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},
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e => {
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assertUnreachable();
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});
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setTimeout(_ => assertEquals(1, onFulfilledValue));
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})();
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(function() {
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let onRejectedReason;
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(async () => Promise.reject(1))().then(
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v => {
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assertUnreachable();
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},
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e => {
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onRejectedReason = e;
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});
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setTimeout(_ => assertEquals(1, onRejectedReason));
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})();
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(function() {
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let resolve;
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let onFulfilledValue;
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const p = new Promise(r => resolve = r);
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resolve({
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then(onFulfilled, onRejected) {
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onFulfilled(1);
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}
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});
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p.then(
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v => {
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onFulfilledValue = v;
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},
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e => {
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assertUnreachable();
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});
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setTimeout(_ => assertEquals(1, onFulfilledValue));
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})();
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(function() {
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let resolve;
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let onRejectedReason;
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const p = new Promise(r => resolve = r);
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resolve({
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then(onFulfilled, onRejected) {
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onRejected(1);
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}
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});
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p.then(
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v => {
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assertUnreachable();
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},
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e => {
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onRejectedReason = e;
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});
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setTimeout(_ => assertEquals(1, onRejectedReason));
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})();
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(function() {
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let onFulfilledValue;
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(async () => ({
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then(onFulfilled, onRejected) {
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onFulfilled(1);
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}
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}))().then(
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v => {
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onFulfilledValue = v;
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},
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e => {
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assertUnreachable();
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});
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setTimeout(_ => assertEquals(1, onFulfilledValue));
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})();
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(function() {
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let onRejectedReason;
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(async () => ({
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then(onFulfilled, onRejected) {
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onRejected(1);
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}
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}))().then(
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v => {
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assertUnreachable();
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},
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e => {
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onRejectedReason = e;
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});
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setTimeout(_ => assertEquals(1, onRejectedReason));
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})();
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