This commit refactors the internals of `wiggle` to have fewer raw pointers and more liberally use `&[UnsafeCell<_>]`. The purpose of this refactoring is to more strictly thread through lifetime information throughout the crate to avoid getting it wrong. Additionally storing `UnsafeCell<T>` at rest pushes the unsafety of access to the leaves of modifications where Rust safety guarantees are upheld. Finally this provides what I believe is a safer internal representation of `WasmtimeGuestMemory` since it technically holds onto `&mut [u8]` un-soundly as other `&mut T` pointers are handed out.
Additionally generated `GuestTypeTransparent` impls in the `wiggle` macro were removed because they are not safe for shared memories as-is and otherwise aren't needed for WASI today. The trait has been updated to indicate that all bit patterns must be valid in addition to having the same representation on the host as in the guest to accomodate this.
Implement Wasmtime's new API as designed by RFC 11. This is quite a large commit which has had lots of discussion externally, so for more information it's best to read the RFC thread and the PR thread.
The BorrowChecker methods get inlined as part of the GuestMemory trait.
The BorrowChecker implementation moves out to the engines. Unfortunately
this does mean having a copy in `test-helpers` along with another in
`wasmtime-wiggle`. The `wasmtime-wiggle` copy will move into `wasmtime`
itself in a subsequent PR.
https://github.com/bytecodealliance/wasmtime/issues/1917
* Shuffle around the wiggle crates
This commit reorganizes the wiggle crates slightly by performing the
following transforms:
* The `crates/wiggle` crate, previously named `wiggle`, was moved to
`crates/wiggle/crates/macro` and is renamed to `wiggle-macro`.
* The `crates/wiggle/crates/runtime` crate, previously named
`wiggle-runtime`, was moved to `crates/wiggle` and is renamed to
`wiggle`.
* The new `wiggle` crate depends on `wiggle-macro` and reexports the macro.
The goal here is that consumers only deal with the `wiggle` crate
itself. No more crates depend on `wiggle-runtime` and all dependencies
are entirely on just the `wiggle` crate.
* Remove the `crates/wiggle/crates` directory
Move everything into `crates/wiggle` directly, like `wasi-common`
* Add wiggle-macro to test-all script
* Fixup a test
