Benjamin Bouvier, Compiler Engineer at Mozilla, writes about speeding up calls from JS to Wasm in Firefox.

If we want more WebAssembly (wasm) adoption, there shouldn’t be a big costly barrier between the two universes. That is, calls from one world to the other should be fast. For a very long time, calls from JS to asm.js/WebAssembly have been quite slow in Firefox. In fact, we didn’t optimize them at all.

He goes on to say…

Starting with Firefox 60, the JIT compiler makes no distinctions between calling a JavaScript function or a WebAssembly function, meaning it uses the same call optimizations for both kinds of function.

Benjamin continues through several more bugs mentioned on the Bugzilla bug board with fixes to speed up calls from JS to Wasm in Firefox.