1495072 - Implement new, faster proposed await semantics

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement, P2)

Description

[Jason Orendorff [:jorendorff]]

See <https://github.com/tc39/ecma262/pull/1250>.

Comment 1

[Jason Orendorff [:jorendorff]]

To be clear, this is a proposal in need of implementation experience. To me, it looks easy to implement and unlikely to cause breakage--and it's a significant performance boost on async code.

Comment 2

[Boris Zbarsky [:bzbarsky]]

Note that the Blink intent for this claims that Edge ships the new behavior already.  Chrome is working on implementing.

Comment 3

[Jason Orendorff [:jorendorff]]

This proposal is small enough that it doesn't seem to be going through the normal TC39 process. Tests have already landed in test262:

test262/language/expressions/await/async-await-interleaved.js
test262/language/expressions/await/async-generator-interleaved.js
test262/language/expressions/await/await-monkey-patched-promise.js
test262/language/expressions/await/for-await-of-interleaved.js

Comment 4

[Jason Orendorff [:jorendorff]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=3efc55e4c5afe8a2963ee7dd1e40af0bc54c3366

Comment 5

[Jason Orendorff [:jorendorff]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=cdd90d8f93700e005254736a50fe5b027151b6bd

Comment 6

[Jason Orendorff [:jorendorff]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=b24f926347cf07135ba071beaecf718646a609f8

Comment 7

[Jason Orendorff [:jorendorff]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=e7e62c531f3c5da3a5e0b353c42d80e9164eefad

Comment 8

[Jason Orendorff [:jorendorff]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=062c8d2376f219984890a225cf8cb599215fa871

Comment 9

[Jason Orendorff [:jorendorff]]

Attachment: Bug 1495072 - Part 1: Add some comments in Promise.cpp detailing algorithm steps. r?arai

This also changes a few functions to follow the unwrapped convention.

This does not do the job thoroughly for our whole implementation of promises
and async generators; but the patch casts enough light that I can see what I'm
doing in part 2.

Comment 10

[Jason Orendorff [:jorendorff]]

Attachment: Bug 1495072 - Part 3: Implement new, faster proposed await semantics. r=arai

This patch implements the proposal in this pull request:
https://github.com/tc39/ecma262/pull/1250

Depends on D21815

Comment 11

[Jason Orendorff [:jorendorff]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=637a13a342708518aed533b0452e46881b68c29e

Comment 12

[Jason Orendorff [:jorendorff]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=3cdb3dfd1ad7813452eaaee9dbcf859a660967b5

Comment 13

[Jason Orendorff [:jorendorff]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=eef87b30a952b0d4f8ef97ae79b766b7b935de1a

Comment 14

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/43c98aac932a
Part 1: Add some comments in Promise.cpp detailing algorithm steps. r=arai
https://hg.mozilla.org/integration/autoland/rev/a14fcb229ddd
Part 2: Implement new, faster proposed await semantics. r=arai

Comment 15

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/43c98aac932a
https://hg.mozilla.org/mozilla-central/rev/a14fcb229ddd

Comment 16

[Ryan VanderMeulen [:RyanVM]]

Backed out the main patch (part 2) for causing bug 1534806.
https://hg.mozilla.org/mozilla-central/rev/1994e1ce54af

Comment 17

[André Bargull [:anba]]

(In reply to Jason Orendorff [:jorendorff] from comment #9)

This also changes a few functions to follow the unwrapped convention.

I don't understand why the asyncGenObj parameter in AsyncGeneratorResumeNext was renamed to unwrappedGenerator. This object is not a possibly unwrapped object from another compartment.

Comment 18

[Jason Orendorff [:jorendorff]]

Attachment: Bug 1495072 - Part 2: Add pref for the await fix. r?arai

Comment 19

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/3ce13940a2a3
Part 2: Add pref for the await fix. r=arai
https://hg.mozilla.org/integration/autoland/rev/269654f1eeb2
Part 3: Implement new, faster proposed await semantics. r=arai

Comment 20

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/3ce13940a2a3
https://hg.mozilla.org/mozilla-central/rev/269654f1eeb2

Comment 21

[Peter Van der Beken [:peterv]]

https://hg.mozilla.org/projects/ash/rev/3ce13940a2a35105b30caae1b1f69db78d4d7cdc
Bug 1495072 - Part 2: Add pref for the await fix. r=arai

https://hg.mozilla.org/projects/ash/rev/269654f1eeb2b6e099af2e5e3e48d07bc1488268
Bug 1495072 - Part 3: Implement new, faster proposed await semantics. r=arai