* Add tests for the interface types output of wasm-bindgen
This commit expands the test suite with assertions about the output of
the interface types pass in wasm-bindgen. The goal here is to actually
assert that we produce the right output and have a suite of reference
files to show how the interface types output is changing over time.
The `reference` test suite added in the previous PR has been updated to
work for interface types as well, generating `*.wit` file assertions
which are printed via the `wit-printer` crate on crates.io.
Along the way a number of bugs were fixed with the interface types
output, such as:
* Non-determinism in output caused by iteration of a `HashMap`
* Avoiding JS generation entirely in interface types mode, ensuring that
we don't export extraneous intrinsics that aren't otherwise needed.
* Fixing location of the stack pointer for modules where it's GC'd out.
It's now rooted in the aux section of wasm-bindgen so it's available
to later passes, like the multi-value pass.
* Interface types emission now works in debug mode, meaning the
`--release` flag is no longer required. This previously did not work
because the `__wbindgen_throw` intrinsic was required in debug mode.
This comes about because of the `malloc_failure` and `internal_error`
functions in the anyref pass. The purpose of these functions is to
signal fatal runtime errors, if any, in a way that's usable to the
user. For wasm interface types though we can replace calls to these
functions with `unreachable` to avoid needing to import the
intrinsic. This has the accidental side effect of making
`wasm_bindgen::throw_str` "just work" with wasm interface types by
aborting the program, but that's not actually entirely intended. It's
hoped that a split of a `wasm-bindgen-core` crate would solve this
issue for the future.
* Run the wasm interface types validator in tests
* Add more gc roots for adapter gc
* Improve stack pointer detection
The stack pointer is never initialized to zero, but some other mutable
globals are (TLS, thread ID, etc), so let's filter those out.
This commit is a pretty large scale rewrite of the internals of wasm-bindgen. No user-facing changes are expected as a result of this PR, but due to the scale of changes here it's likely inevitable that at least something will break. I'm hoping to get more testing in though before landing!
The purpose of this PR is to update wasm-bindgen to the current state of the interface types proposal. The wasm-bindgen tool was last updated when it was still called "WebIDL bindings" so it's been awhile! All support is now based on https://github.com/bytecodealliance/wasm-interface-types which defines parsers/binary format/writers/etc for wasm-interface types.
This is a pretty massive PR and unfortunately can't really be split up any more afaik. I don't really expect realistic review of all the code here (or commits), but some high-level changes are:
* Interface types now consists of a set of "adapter functions". The IR in wasm-bindgen is modeled the same way not.
* Each adapter function has a list of instructions, and these instructions work at a higher level than wasm itself, for example with strings.
* The wasm-bindgen tool has a suite of instructions which are specific to it and not present in the standard. (like before with webidl bindings)
* The anyref/multi-value transformations are now greatly simplified. They're simply "optimization passes" over adapter functions, removing instructions that are otherwise present. This way we don't have to juggle so much all over the place, and instructions always have the same meaning.
