This commit adds a new attribute to `#[wasm_bindgen]`: `start`. The
`start` attribute can be used to indicate that a function should be
executed when the module is loaded, configuring the `start` function of
the wasm executable. While this doesn't necessarily literally configure
the `start` section, it does its best!
Only one crate in a crate graph may indicate `#[wasm_bindgen(start)]`,
so it's not recommended to be used in libraries but only end-user
applications. Currently this still must be used with the `crate-type =
["cdylib"]` annotation in `Cargo.toml`.
The implementation here is somewhat tricky because of the circular
dependency between our generated JS and the wasm file that we emit. This
circular dependency makes running initialization routines (like the
`start` shim) particularly fraught with complications because one may
need to run before the other but bundlers may not necessarily respect
it. Workarounds have been implemented for various emission strategies,
for example calling the start function directly after exports are wired
up with `--no-modules` and otherwise working around what appears to be
a Webpack bug with initializers running in a different order than we'd
like. In any case, this in theory doesn't show up to the end user!
Closes#74
This commit implements a system that will assert that all
`#[wasm_bindgen]` attributes are actually used during compilation. This
should help ensure that we don't sneak in stray attributes that don't
actually end up having any meaning, and hopefully make it a bit easier
to learn `#[wasm_bindgen]`!
This generates a `*.d.ts` file for the wasm file that wasm-bindgen emits
whenever typescript is enable *in addition* to the `*.d.ts` file that
already exists for the JS shim.
Closes#1040
Recently proposed in WebAssembly/tool-conventions#65 each wasm file will
now have an optional `producers` section listing the tooling that went
into producing it. Let's add `wasm-bindgen` in when it processes a wasm
file!
Correction to Pull Request #1035
limira is correct, that particular paragraph is referencing another crate. Considering the wasm-bindgen tutorial links here for the web-sys crate I added another link to the correct cargo link.
Sorry for the mistake.
This commit adds an optimization to `wasm-bindgen` to directly import
and invoke other modules' functions from the wasm module, rather than
going through a shim in the imported bindings. This will be an important
optimization in the future for the host bindings proposal, but for now
it's largely just a proof-of-concept to show that we can do it and is
unlikely to bring about many performance benefits.
The implementation in this commit is largely refactoring to reorganize a
bit how functions are imported, but the implementation happens in
`generate_import_function`.
With this commit, 71/287 imports in the `tests/wasm/main.rs` suite get
hooked up directly to the ES modules, no shims needed!
When returning a ptr/length for allocations and such wasm-bindgen's
generated JS would previously return an array with two elements. It
turns out this doesn't optimize well in all engines! (See #1031). It
looks like we can optimize the array destructuring a bit more, but this
is all generated code which doesn't need to be too readable so we can
also remove the temporary allocation entirely and just pass the second
element of this array through a global instead of the return value.
Closes#1031
This commit updates the `__wbindgen_malloc` shim to avoid throwing a
descriptive error in release mode. This is primarily done for two
reasons:
* If the function is gc'd out in release mode the `"invalid malloc
request"` string is part of data and can't be gc'd automatically.
* In some esoteric JS environments `TextDecoder` isn't always available,
and this relatively core function is very quick to bring in that
requirement early on. For example some recent experimentation with
WebAudio worklets shows that they currently don't have the
`TextDecoder` type available!
This fixes a mistake in allowing a `WebAssembly.Module` to be passed to
the initialization function in `--no-modules` mode by ensuring that it
resolves to a map of an instance/module instead of just resolving to an
instance.
This commit adds a `--remove-name-section` flag to the `wasm-bindgen`
command which will remove the `name` section of the wasm file, used to
indicate the names of functions typically used in debugging. This flag
is off-by-default and will primarily be controlled by wasm-pack,
typically being passed by default with `wasm-pack build --release`.
Closes#1021
This commit switches all imports of JS methods to `structural` by
default. Proposed in [RFC 5] this should increase the performance of
bindings today while also providing future-proofing for possible
confusion with the recent addition of the `Deref` trait for all imported
types by default as well.
A new attribute, `host_binding`, is introduced in this PR as well to
recover the old behavior of binding directly to an imported function
which will one day be the precise function on the prototype. Eventually
`web-sys` will switcsh over entirely to being driven via `host_binding`
methods, but for now it's been measured to be not quite as fast so we're
not making that switch yet.
Note that `host_binding` differs from the proposed name of `final` due
to the controversy, and its hoped that `host_binding` is a good
middle-ground!
[RFC 5]: https://rustwasm.github.io/rfcs/005-structural-and-deref.html
