Work in progress cranelift codegen backend for rust
⚠⚠⚠ This doesn't do much useful yet ⚠⚠⚠
Building
$ git clone https://github.com/bjorn3/rustc_codegen_cranelift.git
$ cd rustc_codegen_cranelift
$ rustup override set nightly # This uses unstable api's which will never be stabilized
$ cargo install xargo # Used for building the sysroot
$ cargo install hyperfine # Used for benchmarking in build.sh
$ cargo build
Usage
$ rustc -Zcodegen-backend=$(pwd)/target/debug/librustc_codegen_cranelift.so my_crate.rs
Build sysroot and test
$ rustup component add rust-src # Make sure the sysroot source is available
$ ./prepare_libcore.sh # Patch the sysroot source for some not yet supported things
$ ./build.sh
Not yet supported
- Good non-rust abi support (non scalars are not yet supported for the "C" abi)
- Checked binops (some missing instructions in cranelift)
- Inline assembly (no cranelift support)
- Varargs (no cranelift support)
- libstd (needs varargs and some other stuff) (tracked here)
- u128 and i128 (no cranelift support)
- SIMD (tracked here)
Troubleshooting
Can't compile
Try updating your nightly compiler. You can try to use an nightly a day or two older if updating rustc doesn't fix it. If you still can't compile it, please fill an issue.
error[E0463]: can't find crate for std while compiling a no_std crate
If you use RUSTFLAGS to pass -Zcodegen-backend to rustc, cargo will compile build-dependencies with those flags too. Because this project doesn't support libstd yet, that will result in an error. I don't know of any way to fix this. :(