WASM instantiation doesn't work properly

[ry]

Here's an example program:

const global = new WebAssembly.Global({value:'i32', mutable:true}, 0);
const mem = new WebAssembly.Memory({initial:10, maximum:100});

let wasmImports = {
  js: { global, mem },
};

async function main() {
  console.log(" ok 1");
  let bytes = Deno.readFileSync('./global.wasm');
  console.log(" ok 2");
  window.wasm = await WebAssembly.instantiate(bytes, wasmImports)
  console.log(" ok 3");
}

main();

It will never reach "ok 3"

The file global.wasm is produced from the following file global.wat:

(module
  (global $g (import "js" "global") (mut i32))
  (import "js" "mem" (memory 1))
  (func (export "getGlobal") (result i32)
        (global.get $g))
  (func (export "incGlobal")
        (global.set $g
                    (i32.add (global.get $g) (i32.const 15))))
  (func (export "retSize") (result i32)
        (memory.size)
  )
)

by running wat2wasm global.wat

[kevinkassimo]

#1325 is also related to this: seems we currently do not wait for any async wasm operations.

[ry]

Debugging further reveals that setting the V8 flag --no-wasm-async-compilation will make this work properly. I think that v8::platform::PumpMessageLoop() needs to be called in order to support async compilation.

[ry]

ref https://bugs.chromium.org/p/v8/issues/detail?id=6263