I am not sure what you actually want but it sounds like something where the component model (the backbone of WASI) might help.

It defines a framework to allow modules to communicate with structured data types by allowing each module to decide how to map it to and from its linear memory (and in future the runtime GC heap)

In your case you could be able to define WIT interfaces for your go types and have your compiler of choice use it to generate all the relevant glue code