2ad77538f5
* Add array generation to wiggle-generate crate This commit: * adds array generation to `wiggle-generate` crate which implies that we can now generate arrays from `witx` files * introduces two test interface functions `foo::reduce_excuses` and `foo::populate_excuses`, and adds matching prop-tests * adds an out-of-boundary check to `HostMemory::mem_area_strat` since now, given we're generating arrays for testing with an arbitrary but bounded number of elements, it is possible to violate the boundary * refactors `Region::extend` to a new signature `extend(times: u32)` which multiplies the current pointer `len` by `times` * fixes bug in `GuestArray::as_ref` and `GuestArrayMut::as_ref_mut` methods where we were not validating the first element (we always started the validation from the second element) * Fix generation of arrays in witx This commit fixes how `arrays` are auto-generated from `witx` files. In particular, the changes include: * Since by design every `array` in `witx` represents an immutable slab of memory, we will only ever operate on `GuestArray` in which case I've gone ahead and removed `GuestArrayMut` so as to unclutter the code somewhat. If we find ourselves in need for it in the future, I reckon it will be better to write it from scratch (since the codebase will inevitably evolve by then considerably) rather than maintaining an unused implementation. * I've rewritten `GuestArrayRef<T>` to be a wrapper for `Vec<GuestRef<T>>`. Also, `GuestArray::as_ref` now borrows each underlying "element" of the array one-by-one rather than borrowing the entire chunk of memory at once. This change is motivated by the inability to coerce type parameter `T` in `GuestArray<T>` in more complicated cases such as arrays of guest pointers `GuestPtr<T>` to `*const T` for reuse in `std::slice::from_raw_parts` call. (In general, the size of Wasm32 pointer is 4 bytes, while ``` std::mem::size_of::<T>() == std::mem::size_of::<GuestPtr<S>>() == 16 ``` which is problematic; i.e., I can't see how I could properly extract guest pointers from slices of 4 bytes and at the same time not allocate.) * I've augmented fuzz tests by (re-)defining two `array` types: ``` (typename $const_excuse_array (array (@witx const_pointer $excuse))) (typename $excuse_array (array (@witx pointer $excuse))) ``` This should hopefully emulate and test the `iovec` and `ciovec` arrays present in WASI spec.
wiggle
An experimental implementation of bytecodealliance/wig crate which
generates Rust bindings from *.witx that are meant to be more idiomatic
and hopefully allowing for easier polyfilling between different WASI
snapshot versions in the future.