Question: no WASM support with JIT enabled intentional?

DeletedUser359

Issue

When visiting a site that requires WASM to function, such as photopea.com, even after toggling JIT on the website won't work.

Examples

I have refreshed the websites and even added them as exceptions in JIT settings, the result hasn't changed.

screenshots

de0u

DeletedUser359 matchboxbananasynergy

On this page: https://selqio.com/tools/webassembly-demo I am able to run WASM in Vanadium if I enable the JIT permission and then reload the page. This is Vanadium 138.0.7204.157.

matchboxbananasynergy

It's expected. There's no usable WASM interpreter so that it can work with JIT disabled. Microsoft Edge has one.

DeletedUser359

Thank you for the very quick reply!

matchboxbananasynergy

de0u Sounds about right, if you enable JIT and refresh, it should work fine.

DeletedUser359

de0u
I did first enable JIT and then refresh the page and it didn't work and told me it's not supported.
The WASM test run says "estimated" so I assume this means it wasn't able to run the benchmark using wasm.

de0u

DeletedUser359 Personally I found that web page confusing, because it appears to display "estimated" results even after it appears to have measured results.

Here are the steps I took:

Go to https://selqio.com/tools/webassembly-demo
Enable JIT
Refresh page. At this point, near the top it says "WebAssembly: Supported" with a green dot.
Scroll down and press "Test WebAssembly" and then "Mandelbrot Set".
Scroll down more and press "Render Mandelbrot Set".
Scroll down a lot more to "Benchmark results". For me it says "2.50x faster with WebAssembly".

Overall I think this particular web page may not provide the most straightforward indication of whether or not WASM is working.

DeletedUser359

de0u At this point, near the top it says "WebAssembly: Supported" with a green dot.

Nope, also Photopea doesn't work either...

de0u

DeletedUser359 If I go to PhotoPea, it complains "no WebAssembly" until I enable it and reload. Then it complains about ad blocking until I disable it and reload.

Again, this is Vanadium 138.0.7204.157 (on a 6a).

DeletedUser359

After a long time of troubleshooting, I realized what the problem was, DCLM is required for JIT to work.

de0u

DeletedUser359 DCLM is required for JIT to work.

Thanks for reporting back! This may help other users later.

Indeed the fundamental nature of JIT compilation is dynamically generating code into memory and executing it.

This seems to be an example of why it is risky to restrict the permissions of built-in GrapheneOS apps. Edit: the good news is that the restriction has been demonstrated to work!