Right now a JS interop callback works like this:
* Each wasm module that gets instantiated will be given it's module
instance (JS calls Dart to set it) via `setThisModule`
* When Dart code calls JS and gives it a callback to invoke, it gave it
this module instance. It will also make the callback wasm function
weakly exported.
* The JS trampoline code, when invoked, would then call the weakly
exported wasm function from the module instance.
We simplify this now by making the Dart code simply give the wasm
function reference to JS, then JS can later on invoke it. No need to
weakly export a function and call back via
`module.exports.<weaklyExportedCallback>`
To ensure binaryen is aware that the wasm function may be called from
JS, we annotate it via the `(@binaryen.js.called)` annotation.
Change-Id: I828dd0cf8d3b36db338792c4e277a4bb94c76faf
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/511080
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Srujan Gaddam <srujzs@google.com>
Martin Kustermann
2d78883f27