Add Webassembly Threads / Threaded Webassembly

[greigs]

I know wasm threads are now supported in chrome but I'd like to know if this is the case for other browsers.
http://webassembly.github.io/spec/core/

(The overall feature rather than wait / notify)

[niklasf]

From my research for stockfish.wasm:

Chromium based (desktop only):

• Since 79: Full support
• Since 74: Support, but without growable shared memory
• 70 to 73: Needs flag chrome://flags/#enable-webassembly-threads or Origin Trial

Firefox:

• Since 79: Full support
• 72 to 78: Structured cloning can no longer be enabled with flags, except on nightlies
• 71: Requires javascript.options.shared_memory and dom.postMessage.sharedArrayBuffer.withCOOP_COEP to be enabled in about:flags
• 68 to 70: Requires javascript.options.shared_memory to be enabled in about:flags

Other browsers: No support.

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Updated 2020-11-05

[kiding]

Along with SharedArrayBuffer being re-enabled, WebAssembly Threads are also available since Firefox 79.

[wffurr]

Threads in FF 79 (and Chrome Android / M91 desktop) will require the COOP/COEP headers as a mitigation for Spectre-style side-channel attacks: https://web.dev/coop-coep/

NodeJS supports threads as of v12.0.0 but requires the v8 flag --experimental-wasm-threads.

[Schweinepriester]

Seemingly available in Safari 14.1 https://webkit.org/blog/11648/new-webkit-features-in-safari-14-1/#:~:text=WebAssembly-,threading,-WebAssembly:

In this release, WebKit added WASM threading to support CPU-intensive applications that need to work across CPU threads to preserve application performance.

Not sure about TP, didn't find it in the release notes…

[rtrussell]

Webassembly Threads still not supported in iOS browsers, sadly. Does anybody know when this might be coming?

[wffurr]

It's been supported since iOS Safari 15.2 with COOP/COEP enabled IIUC.