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Comment by TekMol

3 days ago

The reason I don't use WebAssembly is that browsers do not support the text format.

Often it is just a tiny loop that one wants to optimize. Writing it manually in WAT would be nice. But adding a whole toolchain and a compile step to the stack is not worth it.

Shouldn't it be straight forward to compile WAT to WASM? I hope one day browsers will support it.

26 comments

TekMol

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rav  3 days ago

You could use handwritten asmjs in that case. I did it at work to improve performance on some pixel-wise software rendering we were doing. (We have since then switched to WebGL, but asmjs was a nice stepping stone.) If I recall correctly, it basically boils down to using small fixed size arrays and appending "|0" after each uint32 operation and "+" in front of each float32 operation - so it's something you can do by hand. Of course, one of my colleagues then made a tweak which gave a surprisingly huge slowdown - you should probably declare loudly (with comments etc.) that a certain code block is intended to be asmjs if you do this in a large codebase.

  • TekMol  3 days ago

    asmjs is great. Imho the better approach than wasm. But it seems to not have great browser support (no Safari for example). And support is probably not getting better in the future.

flohofwoe  3 days ago

Chances are that you won't get much out of WASM for such small snippets anyway. Contrary to popular belief, well-written Javascript isn't drastically slower than WASM in most situations.

  • TekMol  3 days ago

    Then why does WASM exist? If someone wants to compile whatever other language to run in the browser, why not just compile it to well-written JavaScript?

    • masklinn  3 days ago

      Mozilla tried that with asmjs. Turns out javascript has pretty half-assed semantics (notably around integer types), nobody wants to expand it to a useful compilation (asmjs was mostly an optimisation for hand-written code) target, and few want to compile to text, especially javascript.

      Having a proper and well defined ISA is a lot more compelling.

      Not only that, but it allows WASM-only compilers and runtimes with none of the JS baggage, and thus use of WASM outside of a browser context and with significantly lower resources requirements.

      3 replies →

    • flohofwoe  3 days ago

      Simple: Javascript can focus on being a human-friendly programming language, while WASM can focus on being a compile target. If you've been around in the asm.js times, this conflict was a real concern.

      9 replies →

    • sirwhinesalot  3 days ago

      We used to have asm.js for that. For various reasons wasm is a replacement for it. JS doesn't even have proper integer types, it is not a good target language.

      1 reply →

pjmlp  3 days ago

You can do that easily with binaryen already, and make use of parseText().

https://web.dev/articles/binaryen

  • TekMol  3 days ago

    Not sure what you mean. I guess this is a misunderstanding.

    What I mean is that I would like something like this to work:

        code = `(
        func $add (param $a i32) (param $b i32) (result i32)
            local.get $a
            local.get $b
            i32.add
    )`;
    module = WebAssembly.compile(code);
    alert(module.add(3, 5)); // alerts "8".