Bug 191064 – iOS simulator does not support WebAssembly

• Component: WebAssembly
• Status: RESOLVED FIXED

[Ashley Gullen]

The iOS simulator in Xcode does not appear to support WebAssembly. Content that works on a real device does not work on the simulator, as 'WebAssembly' appears to be undefined.

If you build a Cordova app that depends on WebAssembly, then the simulator is not fit for purpose. This includes all iOS content published by Construct 3 (www.construct.net).

[Radar WebKit Bug Importer]

<rdar://problem/45681669>

[Jonathan Beri]

I can confirm this is still an issue, tested on iOS 12.4. Is anyone looking into enabling WebAssembly in the simulator?

[Alexey Proskuryakov]

Updated Apple internal reference:

rdar://problem/40830087

[Sanjay Kumar]

Please fix. Lack of WebAssembly is a serious hindrance - I cant afford to buy so many iOS devices to test an Web-assembly is basic minimum requirement for my App. Thanks.

[Ashley Gullen]

Perhaps the new WebAssembly interpreter could help fix this?: https://bugs.webkit.org/show_bug.cgi?id=194257

[Ashley Gullen]

We still get regular reports of this, since none of our framework's content can work in the iOS simulator due to this bug. Is there any news on it?

[Haakon Jack]

This is still an issue. A fix would be greatly appreciated.

[Keith Miller]

Created attachment 405000 [details]
Patch

[Yusuke Suzuki]

Comment on attachment 405000 [details]
Patch

r=me

[Chris Dumez]

Comment on attachment 405000 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=405000&action=review

> Source/WTF/ChangeLog:8
> +        Now that it seems we can JIT in the Simulator we should enable

A lot of layout tests are skipped in iOS simulator due to lack of WebAssembly. We should unstop them too.

[Chris Dumez]

Comment on attachment 405000 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=405000&action=review

>> Source/WTF/ChangeLog:8
>> +        Now that it seems we can JIT in the Simulator we should enable
> 
> A lot of layout tests are skipped in iOS simulator due to lack of WebAssembly. We should unstop them too.

LayoutTests/platform/ios-simulator/TestExpectations :

# Simulator doesn't support WebAssembly.
http/tests/security/contentSecurityPolicy/WebAssembly-allowed.html [ Failure ]
http/tests/security/contentSecurityPolicy/WebAssembly-blocked-in-about-blank-iframe.html [ Failure ]
http/tests/security/contentSecurityPolicy/WebAssembly-blocked-in-external-script.html [ Failure ]
http/tests/security/contentSecurityPolicy/WebAssembly-blocked-in-subframe.html [ Failure ]
http/tests/security/contentSecurityPolicy/WebAssembly-blocked.html [ Failure ]
imported/w3c/web-platform-tests/html/webappapis/scripting/processing-model-2/integration-with-the-javascript-agent-formalism/requires-failure.https.any.html [ Failure ]
imported/w3c/web-platform-tests/html/webappapis/scripting/processing-model-2/integration-with-the-javascript-agent-formalism/requires-failure.https.any.serviceworker.html [ Failure ]
imported/w3c/web-platform-tests/html/webappapis/scripting/processing-model-2/integration-with-the-javascript-agent-formalism/requires-success.any.worker.html [ Failure ]
wasm/iframe-postmessage.html [ Skip ]
wasm/iframe-parent-postmessage.html [ Skip ]
wasm/window-postmessage.html [ Skip ]
imported/w3c/web-platform-tests/encoding/encodeInto.any.html [ Skip ]
imported/w3c/web-platform-tests/encoding/encodeInto.any.worker.html [ Skip ]
imported/w3c/web-platform-tests/encoding/streams/decode-utf8.any.html [ Skip ]
imported/w3c/web-platform-tests/encoding/streams/decode-utf8.any.worker.html [ Skip ]
imported/w3c/web-platform-tests/encoding/textdecoder-copy.any.html [ Skip ]
imported/w3c/web-platform-tests/encoding/textdecoder-copy.any.worker.html [ Skip ]
imported/w3c/web-platform-tests/encoding/textdecoder-streaming.any.html [ Skip ]
imported/w3c/web-platform-tests/encoding/textdecoder-streaming.any.worker.html [ Skip ]

[Keith Miller]

Created attachment 405015 [details]
Patch for landing

[Keith Miller]

(In reply to Chris Dumez from comment #10)
> Comment on attachment 405000 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=405000&action=review
> 
> > Source/WTF/ChangeLog:8
> > +        Now that it seems we can JIT in the Simulator we should enable
> 
> A lot of layout tests are skipped in iOS simulator due to lack of
> WebAssembly. We should unstop them too.

Indeed, I'll unstop.

[EWS]

Committed r264745: <https://trac.webkit.org/changeset/264745>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 405015 [details].

[Aakash Jain]

(In reply to EWS from comment #14)
> Committed r264745: <https://trac.webkit.org/changeset/264745>
This broke following 3 ios-wk2 tests as also indicated by EWS.
- imported/w3c/web-platform-tests/webaudio/the-audio-api/the-audiobuffer-interface/audiobuffer-copy-channel.html
- imported/w3c/web-platform-tests/xhr/send-data-sharedarraybuffer.any.html
- imported/w3c/web-platform-tests/xhr/send-data-sharedarraybuffer.any.worker.html

[Yusuke Suzuki]

Re-opened since this is blocked by bug 214681

[Chris Dumez]

(In reply to Yusuke Suzuki from comment #16)
> Re-opened since this is blocked by bug 214681

imported/w3c/web-platform-tests/webaudio/the-audio-api/the-audiobuffer-interface/audiobuffer-copy-channel.html
imported/w3c/web-platform-tests/xhr/send-data-sharedarraybuffer.any.html
imported/w3c/web-platform-tests/xhr/send-data-sharedarraybuffer.any.worker.html

All 3 were *progressions* and merely needed a rebaseline.

[Aakash Jain]

(In reply to Chris Dumez from comment #17)
> All 3 were *progressions* and merely needed a rebaseline.
It wasn't immediately obvious to me, and these test failures were slowing down ios-wk2 EWS. I didn't want to delay and let patches pileup on ios-wk2 queue.

[Chris Dumez]

(In reply to Aakash Jain from comment #18)
> (In reply to Chris Dumez from comment #17)
> > All 3 were *progressions* and merely needed a rebaseline.
> It wasn't immediately obvious to me, and these test failures were slowing
> down ios-wk2 EWS. I didn't want to delay and let patches pileup on ios-wk2
> queue.

No worries, I guess somebody did not wait for the iOS EWS bubble before landing an iOS-specific patch :P

[Keith Miller]

(In reply to Chris Dumez from comment #19)
> (In reply to Aakash Jain from comment #18)
> > (In reply to Chris Dumez from comment #17)
> > > All 3 were *progressions* and merely needed a rebaseline.
> > It wasn't immediately obvious to me, and these test failures were slowing
> > down ios-wk2 EWS. I didn't want to delay and let patches pileup on ios-wk2
> > queue.
> 
> No worries, I guess somebody did not wait for the iOS EWS bubble before
> landing an iOS-specific patch :P

I maintain my position that commit queue should block on EWS! D:

[Keith Miller]

Created attachment 405068 [details]
Patch for landing

[EWS]

Tools/Scripts/svn-apply failed to apply attachment 405068 [details] to trunk.
Please resolve the conflicts and upload a new patch.

[Keith Miller]

Created attachment 405070 [details]
Patch for landing

[EWS]

ChangeLog entry in LayoutTests/ChangeLog contains OOPS!.

[Keith Miller]

Relanded in r264801.

[Ashley Gullen]

Just tried the iOS simulator in Xcode 12 and it does support WebAssembly! Great stuff, thanks for the fix!