> ⚠⚠⚠ Certain kinds of FFI don't work yet. ⚠⚠⚠
-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/master/cranelift).
+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.
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.
> You should prefer using the Cargo method.
```bash
-$ $cg_clif_dir/build/cg_clif my_crate.rs
+$ $cg_clif_dir/build/bin/cg_clif my_crate.rs
```
### Jit mode
or
```bash
-$ $cg_clif_dir/build/cg_clif --jit my_crate.rs
+$ $cg_clif_dir/build/bin/cg_clif -Cllvm-args=mode=jit -Cprefer-dynamic my_crate.rs
+```
+
+There is also an experimental lazy jit mode. In this mode functions are only compiled once they are
+first called. It currently does not work with multi-threaded programs. When a not yet compiled
+function is called from another thread than the main thread, you will get an ICE.
+
+```bash
+$ $cg_clif_dir/build/cargo.sh lazy-jit
```
### Shell
```bash
function jit_naked() {
- echo "$@" | $cg_clif_dir/build/cg_clif - --jit
+ echo "$@" | $cg_clif_dir/build/bin/cg_clif - -Cllvm-args=mode=jit -Cprefer-dynamic
}
function jit() {