58bb5dd953
`funcref`s are implemented as `NonNull<VMCallerCheckedAnyfunc>`. This should be more efficient than using a `VMExternRef` that points at a `VMCallerCheckedAnyfunc` because it gets rid of an indirection, dynamic allocation, and some reference counting. Note that the null function reference is *NOT* a null pointer; it is a `VMCallerCheckedAnyfunc` that has a null `func_ptr` member. Part of #929
This crate performs the translation from a wasm module in binary format to the in-memory form of the Cranelift IR.
If you're looking for a complete WebAssembly implementation that uses this library, see Wasmtime.