That's not what the parent was asking. They were asking if WASM has an FFI interface for runtimes that want to not execute the WASM code entirely sandboxed from the host, but rather want to allow you to dlload(2) code into the OS process hosting the WASM interpreter and call it through WASM ops.

Presumably, https://github.com/CraneStation/wasmtime would benefit from such an FFI API being specified.