ra-jit 发布 Rust 即时编译工具提速 24 倍

原标题：24x faster Rust compilation with rust-analyzer

68AI 研判分

核心综述

开源项目 ra-jit 推出基于 rust-analyzer 的即时编译技术，实现保存文件后毫秒级热更新运行中程序。该工具通过增量重编仅修改函数，将单次编辑构建时间从 169ms 降至 7ms，提升约 24 倍，但暂不支持借用检查且仅限 Apple Silicon 实时预览。

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本文目录6 个章节

ra-jit

Edit Rust. See it change in milliseconds, in the program that is already running.

文本

nix run github:indexable-inc/ra-jit

That opens a Game of Life window you can edit while it runs (live on macOS Apple silicon).

Editing the running Game of Life: rule, colours and speed change live

For release news: Watch → Custom → Releases on GitHub.

What you get

Live edits. Save a file and the running program has the new code about a millisecond later. Its state stays. (docs/live.md)
Fast builds. After the first build, an edit rebuilds only the functions you changed. No rustc, no waiting.
Same cargo. cargo ra-jit build|run|test|check in any project.

How fast

Live edit to running code, Game of Life demo (median of 20 edits, one 96-core Linux machine):

Edit	incremental `cargo build`	ra-jit live
One function	169 ms	7 ms	24x
One function, 300 new functions added	282 ms	60 ms	4.7x

Edit, then build (generated 200-crate workspace, Linux x86-64, 8 CPUs, both warm and incremental, same linker, median of three):

Edit	cargo	ra-jit
A function in the main crate	1.76 s	0.42 s	4.2x
A function in a crate everything depends on	6.33 s	0.60 s	10.6x
Functions in 30 crates at once	6.26 s	0.62 s	10.1x
A new function	2.09 s	0.56 s	3.7x
A signature used in every crate	13.87 s	10.87 s	1.3x

Not measured yet: real projects, and a build from nothing against a fresh cargo build (#benchmarks).

Try it on your project

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nix run github:indexable-inc/ra-jit#ra-jit -- build

No nix? cargo +1.99.0 install --locked ra-jit, or put the binaries from a release on your PATH. Then use Rust 1.99.0 with its source: rustup toolchain install 1.99.0 -c rust-src && rustup override set 1.99.0.

Use it as your normal `cargo build`

文本

nix profile install github:indexable-inc/ra-jit#ra-jit
ra-jit enable

From then on plain cargo build, run, test and check in any project go through ra-jit. ra-jit disable puts your cargo config back.

Live edits

Add the crate and poll once per frame:

TOML

ra-jit-live = "0.1"

RUST

let mut live = ra_jit_live::Live::start().ok();
loop {
    if let Some(outcome) = live.as_mut().and_then(|it| it.poll()) {
        eprintln!("ra-jit: {outcome}");
    }
    // ...your frame
}

What to know

Live edits work on macOS Apple silicon only. Elsewhere you still get fast builds.
No borrow checker: keep running cargo check.
Rust 1.99.0 only.
Changing a struct the program is using asks for a restart.

More: how it works, full results, what is supported.