test_dlfcn_asyncify doesn't work with MEMORY64 + JSPI

[sbc100]

SyntaxError: Cannot convert [object Promise] to a BigInt
    at BigInt (<anonymous>)
    at __dlopen_js (/usr/local/google/home/sbc/dev/wasm/emscripten/out/test/src.js:4405:12)
    at src.wasm._dlopen (wasm://wasm/src.wasm-000200ae:wasm-function[29]:0x90b)
    at src.wasm.dlopen (wasm://wasm/src.wasm-000200ae:wasm-function[28]:0x887)
    at src.wasm.main (wasm://wasm/src.wasm-000200ae:wasm-function[17]:0x53e)
    at ret.<computed> (/usr/local/google/home/sbc/dev/wasm/emscripten/out/test/src.js:4788:24)
    at callMain (/usr/local/google/home/sbc/dev/wasm/emscripten/out/test/src.js:4940:15)
    at doRun (/usr/local/google/home/sbc/dev/wasm/emscripten/out/test/src.js:4983:24)
    at run (/usr/local/google/home/sbc/dev/wasm/emscripten/out/test/src.js:4996:5)
    at removeRunDependency (/usr/local/google/home/sbc/dev/wasm/emscripten/out/test/src.js:422:7)
    at receiveInstance (/usr/local/google/home/sbc/dev/wasm/emscripten/out/test/src.js:571:5)
    at receiveInstantiationResult (/usr/local/google/home/sbc/dev/wasm/emscripten/out/test/src.js:581:12)
    at createWasm (/usr/local/google/home/sbc/dev/wasm/emscripten/out/test/src.js:604:19)

The problem is that we inject BigInt(ret) since _dlopen_js returns a pointer, but in the JSPI case it returns a promise which cannot be converted to BigInt.

[sbc100]

@brendandahl any ideas what we should do in this case?

[brendandahl]

I think we can make jsifier aware that the function is async and add async to the function then do return BigInt(await ret);.

[sbc100]

Are all functions marked as async guaranteed to return a promise in JSPI mode?

[sbc100]

Sounds like a good fix if so.

[brendandahl]

I don't think it's required, but using await on a non-promise will work too.

[sbc100]

I don't think it's required, but using await on a non-promise will work too.

Great. And the functions will already be marked as async I guess.

[brendandahl]

It may not be marked async already. Right now we have two ways, either the function is async function myFoo or using the library decorator myFoo__async: true. In the latter case the function may not necessarily be async.

[sbc100]

I see, and we cannot use await unless we mark the function as async right? Or can we?

[brendandahl]

The function has to be async to use await.

FWIW, JSPI has changed quite a bit since we originally made __async stuff. Now JSPI wrapped imports will always suspend (i.e. the synchronous fast return is gone now), so it should be fine if we now require __async functions to return a promise.

[brendandahl]

*return a promise = be marked async

[sbc100]

Can you automatically add the async keyword when a function is marked as __async ? e.g in the case of dlopen_js?

[sbc100]

Do you want to take a crack at fixing test_dlfcn_asyncify_jspi ? Or should I?

[brendandahl]

I can take a look.

[brendandahl]

Fixed by #23588