1225406 - [meta] Enable SharedArrayBuffer and Atomics on DevEd, Aurora, Beta, and Release

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Lars T Hansen [:lth]]

The gating condition for letting SAB+Atomics ride the trains (up to, but not including, Release) is to get the spec to Stage 2 in TC39.  At the time of writing we're not there yet.

Not sure what needs to be done technically.  There's a condition in js/src/moz.build that currently constrains the feature to nightly; perhaps it can simply be generalized to include tests for all-but-release.

Comment 1

[Lars T Hansen [:lth]]

Update: After some discussion at Mozlando the decision is to let SAB+Atomics ride the trains - all the way - behind a pref, starting as soon as the code can be written.  The FF45 train departs mid-week next week, that may be too soon for the work that needs to be done and too risky to just cram it in.  So the FF46 train is the target.

As part of that work, a few work items will need to be completed and they will appear as dependencies on this bug:

- make the TypedArray implementation compliant with the SAB spec
- disallow futexWait blocking on the main thread, needs to be backed by a spec change
- double-check that all the feature gating is working correctly
- implement a suitable pref

My intent is to keep this available in Nightly even without the pref (ie the pref defaults to true in Nightly).  Please, somebody, scream if that is inappropriate.

Comment 2

[Lars T Hansen [:lth]]

(Disallowing futexWait on the main thread will also require a number of test cases to be written and rewritten.)

Comment 3

[Lars T Hansen [:lth]]

Will ride with FF46 when that branches on Jan 25.

Comment 4

[Lars T Hansen [:lth]]

Reopening because there's another patch coming for the #define.

Comment 5

[Marco Castelluccio [:marco]]

To clarify, is this now enabled by default starting from Firefox 46?

Comment 6

[Lars T Hansen [:lth]]

(In reply to Marco Castelluccio [:marco] from comment #5)
> To clarify, is this now enabled by default starting from Firefox 46?

No.  It is only enabled by default on Nightly.

I should not have closed this bug, I was being careless while I was cleaning up.  I will reopen.

Comment 7

[Lars T Hansen [:lth]]

Closing this because the blockers are all closed, but note that we may back out the code so as not to enable this on Release.  Bug 1312446 for more information.

Comment 8

[Florian Scholz (Open Web Docs)]

Removing ddn, bug 1312446 has the info on what is shipped when and also has ddn.