58 lines
2.3 KiB
Markdown
58 lines
2.3 KiB
Markdown
# Cranelift codegen backend for rust
|
|
|
|
The goal of this project is to create an alternative codegen backend for the rust compiler based on [Cranelift](https://github.com/bytecodealliance/wasmtime/blob/main/cranelift).
|
|
This has the potential to improve compilation times in debug mode.
|
|
If your project doesn't use any of the things listed under "Not yet supported", it should work fine.
|
|
If not please open an issue.
|
|
|
|
## Building and testing
|
|
|
|
```bash
|
|
$ git clone https://github.com/bjorn3/rustc_codegen_cranelift.git
|
|
$ cd rustc_codegen_cranelift
|
|
$ ./prepare.sh # download and patch sysroot src and install hyperfine for benchmarking
|
|
$ ./build.sh
|
|
```
|
|
|
|
To run the test suite replace the last command with:
|
|
|
|
```bash
|
|
$ ./test.sh
|
|
```
|
|
|
|
This will implicitly build cg_clif too. Both `build.sh` and `test.sh` accept a `--debug` argument to
|
|
build in debug mode.
|
|
|
|
Alternatively you can download a pre built version from [GHA]. It is listed in the artifacts section
|
|
of workflow runs. Unfortunately due to GHA restrictions you need to be logged in to access it.
|
|
|
|
[GHA]: https://github.com/bjorn3/rustc_codegen_cranelift/actions?query=branch%3Amaster+event%3Apush+is%3Asuccess
|
|
|
|
## Usage
|
|
|
|
rustc_codegen_cranelift can be used as a near-drop-in replacement for `cargo build` or `cargo run` for existing projects.
|
|
|
|
Assuming `$cg_clif_dir` is the directory you cloned this repo into and you followed the instructions (`prepare.sh` and `build.sh` or `test.sh`).
|
|
|
|
In the directory with your project (where you can do the usual `cargo build`), run:
|
|
|
|
```bash
|
|
$ $cg_clif_dir/build/cargo.sh build
|
|
```
|
|
|
|
This will build your project with rustc_codegen_cranelift instead of the usual LLVM backend.
|
|
|
|
For additional ways to use rustc_codegen_cranelift like the JIT mode see [full_usage.md](docs/full_usage.md).
|
|
|
|
## Env vars
|
|
|
|
See [env_vars.md](docs/env_vars.md) for all env vars used by rustc_codegen_cranelift.
|
|
|
|
## Not yet supported
|
|
|
|
* Inline assembly ([no cranelift support](https://github.com/bytecodealliance/wasmtime/issues/1041))
|
|
* On Linux there is support for invoking an external assembler for `global_asm!` and `asm!`.
|
|
`llvm_asm!` will remain unimplemented forever. `asm!` doesn't yet support reg classes. You
|
|
have to specify specific registers instead.
|
|
* SIMD ([tracked here](https://github.com/bjorn3/rustc_codegen_cranelift/issues/171), some basic things work)
|