WebAssembly.Instance is disallowed on the main thread, if the buffer size is larger than 8MB

[MichaelBelousov]

I have a WebAssembly blob which includes a very large codebase, so while it's 6.6MB release small, it's >200MB in debug mode, which started triggering the following error in chromium:

RangeError: WebAssembly.Instance is disallowed on the main thread, if the buffer size is larger than 8MB. Use WebAssembly.instantiate, or use the flag `--enable-features=WebAssemblyUnlimitedSyncCompilation`.

With this stack:

instantiateWebAssembly (module-loading.js:148)
await in instantiateWebAssembly
(anonymous) (module-loading.js:152)
loadModule (module-loading.js:166)
(anonymous) (js.zig:9714)

Using [email protected]

Skimming the code, it looks like there's probably an option that can get around this, but I don't see anything in the documentation. How can I best get around this?

[MichaelBelousov]

FWIW here's a very ugly zigar-runtime patch to get around it:

diff --git a/dist/features/module-loading.js b/dist/features/module-loading.js
index 82655b699395e5a556d34447b8ddbceb27a6fd65..69287312a98c251435a49f7b69d2b99b2bce44e2 100644
--- a/dist/features/module-loading.js
+++ b/dist/features/module-loading.js
@@ -145,7 +148,10 @@ var moduleLoading = mixin({
         shared: multithreaded,
       });
       this.initialTableLength = tableInitial;
-      return new w.Instance(executable, exports);
+      return WebAssembly.instantiateStreaming(fetch(res.url), exports).then(w => w.instance);
     },
     loadModule(source, options) {
       return this.initPromise = (async () => {

Of course I think this is just temporary, and a better solution is needed.