* Remove global state for trap registration
There's a number of changes brought about in this commit, motivated by a
few things. One motivation was to remove an instance of using
`lazy_static!` in an effort to remove global state and encapsulate it
wherever possible. A second motivation came when investigating a
slowly-compiling wasm module (a bit too slowly) where a good chunk of
time was spent in managing trap registrations.
The specific change made here is that `TrapRegistry` is now stored
inside of a `Compiler` instead of inside a global. Additionally traps
are "bulk registered" for a module rather than one-by-one. This form of
bulk-registration allows optimizing the locks used here, where a lock is
only held for a module at-a-time instead of once-per-function.
With these changes the "unregister" logic has also been tweaked a bit
here and there to continue to work. As a nice side effect the `Compiler`
type now has one fewer field that requires actual mutability and has
been updated for multi-threaded compilation, nudging us closer to a
world where we can support multi-threaded compilation. Yay!
In terms of performance improvements, a local wasm test file that
previously took 3 seconds to compile is now 10% faster to compile,
taking ~2.7 seconds now.
* Perform trap resolution after unwinding
This avoids taking locks in signal handlers which feels a bit iffy...
* Remove `TrapRegistration::dummy()`
Avoid an case where you're trying to lookup trap information from a
dummy module for something that happened in a different module.
* Tweak some comments
* Document and update the API of the `externals.rs` module
This commit ensures that all public methods and items are documented in
the `externals.rs` module, notably all external values that can be
imported and exported in WebAssembly. Along the way this also tidies up
the API and fixes a few bugs:
* `Global::new` now returns a `Result` and fails if the provided value
does not match the type of the global.
* `Global::set` now returns a `Result` and fails if the global is either
immutable or the provided value doesn't match the type of the global.
* `Table::new` now fails if the provided initializer does not match the
element type.
* `Table::get` now returns `Option<Val>` instead of implicitly returning
null.
* `Table::set` now returns `Result<()>`, returning an error on out of
bounds or if the input type is of the wrong type.
* `Table::grow` now returns `Result<u32>`, returning the previous number
of table elements if succesful or an error if the maximum is reached
or the initializer value is of the wrong type. Additionally a bug was
fixed here where if the wrong initializer was provided the table would
be grown still, but initialization would fail.
* `Memory::data` was renamed to `Memory::data_unchecked_mut`.
Additionally `Memory::data_unchecked` was added. Lots of caveats were
written down about how using the method can go wrong.
* `Memory::grow` now returns `Result<u32>`, returning an error if growth
fails or the number of pages previous the growth if successful.
* Run rustfmt
* Fix another test
* Update crates/api/src/externals.rs
Co-Authored-By: Sergei Pepyakin <s.pepyakin@gmail.com>
Co-authored-by: Sergei Pepyakin <s.pepyakin@gmail.com>
In preparation for eventual support for wasm interface types this commit
moves around a few panics internally inside of conversions between the
`wasmtime` crate and the underlying jit support crates. This should have
any immediately-visible user changes, but the goal is that this'll help
support interface types which means `wasmtime` will have types that are
not supported by wasmtime itself and we'll be able to more gracefully
support that with error messages instead of accidental panics.
* Refactor the `types.rs` types and structures
A few changes applied along the way:
* Documentation added to most methods and types.
* Limits are now stored with the maximum as optional rather than a
sentinel u32 value for `None`.
* The `Name` type was removed in favor of just using a bare `String`.
* The `Extern` prefix in the varaints of `ExternType` has been removed
since it was redundant.
* Accessors of `ExternType` variants no longer panic, and unwrapping
versions were added with "unwrap" in the name.
* Fields and methods named `r#type` were renamed to `ty` to avoid
requiring a raw identifier to use them.
* Remove `fail-fast: false`
This was left around since the development of GitHub Actions for
wasmtime, but they're no longer needed!
* Fix compilation of the test-programs code
* Fix compilation of wasmtime-py package
* Run rustfmt
* Migrate back to `std::` stylistically
This commit moves away from idioms such as `alloc::` and `core::` as
imports of standard data structures and types. Instead it migrates all
crates to uniformly use `std::` for importing standard data structures
and types. This also removes the `std` and `core` features from all
crates to and removes any conditional checking for `feature = "std"`
All of this support was previously added in #407 in an effort to make
wasmtime/cranelift "`no_std` compatible". Unfortunately though this
change comes at a cost:
* The usage of `alloc` and `core` isn't idiomatic. Especially trying to
dual between types like `HashMap` from `std` as well as from
`hashbrown` causes imports to be surprising in some cases.
* Unfortunately there was no CI check that crates were `no_std`, so none
of them actually were. Many crates still imported from `std` or
depended on crates that used `std`.
It's important to note, however, that **this does not mean that wasmtime
will not run in embedded environments**. The style of the code today and
idioms aren't ready in Rust to support this degree of multiplexing and
makes it somewhat difficult to keep up with the style of `wasmtime`.
Instead it's intended that embedded runtime support will be added as
necessary. Currently only `std` is necessary to build `wasmtime`, and
platforms that natively need to execute `wasmtime` will need to use a
Rust target that supports `std`. Note though that not all of `std` needs
to be supported, but instead much of it could be configured off to
return errors, and `wasmtime` would be configured to gracefully handle
errors.
The goal of this PR is to move `wasmtime` back to idiomatic usage of
features/`std`/imports/etc and help development in the short-term.
Long-term when platform concerns arise (if any) they can be addressed by
moving back to `no_std` crates (but fixing the issues mentioned above)
or ensuring that the target in Rust has `std` available.
* Start filling out platform support doc
