a117c057fb
Previously `wasm-bindgen` would take its `breaks_if_inlined` shims and attempt to remove them entirely, replacing calls to `breaks_if_inlined` to the imported closure factories. This worked great in that it would remove the `breaks_if_inlined` funtion entirely, removing the "cost" of the `#[inline(never)]`. Unfortunately as #864 discovered this is "too clever by half". LLVM's aggressive optimizations won't inline `breaks_if_inlined`, but it may still change the ABI! We can't replace calls to `breaks_if_inlined` if the signature changes, because the function its calling has a fixed signature. This commit cops out a bit and instead of replacing calls to `breaks_if_inlined` to the imported closure factories, we instead rewrite calls to `__wbindgen_describe_closure` to the closure factories. This means that the `breaks_if_inlined` shims do not get removed. It also means that the closure factory shims have a third and final argument (what would be the function pointer of the descriptor function) which is dead and unused. This should be a functional solution for now and let us iterate on a true fix later on (if needed). For now the cost of this `#[inline(never)]` and the extra unused argument should be quite small. Closes #864 |
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| .cargo | ||
| crates | ||
| examples | ||
| guide | ||
| releases | ||
| src | ||
| tests | ||
| .appveyor.yml | ||
| .gitattributes | ||
| .gitignore | ||
| .travis.yml | ||
| build.rs | ||
| Cargo.toml | ||
| CHANGELOG.md | ||
| CONTRIBUTING.md | ||
| LICENSE-APACHE | ||
| LICENSE-MIT | ||
| package.json | ||
| publish.rs | ||
| README.md | ||
wasm-bindgen
Facilitating high-level interactions between wasm modules and JavaScript.
Import JavaScript things into Rust and export Rust things to JavaScript.
extern crate wasm_bindgen;
use wasm_bindgen::prelude::*;
// Import the `window.alert` function from the Web.
#[wasm_bindgen]
extern {
fn alert(s: &str);
}
// Export a `greet` function from Rust to JavaScript, that alerts a
// hello message.
#[wasm_bindgen]
pub fn greet(name: &str) {
alert(&format!("Hello, {}!", name));
}
Use exported Rust things from JavaScript with ECMAScript modules!
import { greet } from "./hello_world";
greet("World!");
Features
-
Lightweight. Only pay for what you use.
wasm-bindgenonly generates bindings and glue for the JavaScript imports you actually use and Rust functionality that you export. For example, importing and using thedocument.querySelectormethod doesn't causeNode.prototype.appendChildorwindow.alertto be included in the bindings as well. -
ECMAScript modules. Just import WebAssembly modules the same way you would import JavaScript modules. Future compatible with WebAssembly modules and ECMAScript modules integration.
-
Designed with the "host bindings" proposal in mind. Eventually, there won't be any JavaScript shims between Rust-generated wasm functions and native DOM methods. Because the wasm functions are statically type checked, some of those native methods' dynamic type checks should become unnecessary, promising to unlock even-faster-than-JavaScript DOM access.
Guide
📚 Read the wasm-bindgen guide here! 📚
API Docs
License
This project is licensed under either of
- Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Contribution
See the "Contributing" section of the guide for information on
hacking on wasm-bindgen!
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this project by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.