WIP Cranelift codegen backend for rust

⚠⚠⚠ Certain kinds of FFI don't work yet. ⚠⚠⚠

Building

$ 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
$ ./test.sh --release

Usage

$cg_clif_dir is the directory you cloned this repo into in the following instructions.

Cargo

$ CHANNEL="release" $cg_clif_dir/cargo.sh run

If you compiled cg_clif in debug mode (aka you didn't pass --release to ./test.sh) you should use CHANNEL="debug" instead or omit CHANNEL="release" completely.

Rustc

You should prefer using the Cargo method.

$ rustc +$(cat $cg_clif_dir/rust-toolchain) -Cpanic=abort -Zcodegen-backend=$cg_clif_dir/target/release/librustc_codegen_cranelift.so --sysroot $cg_clif_dir/build_sysroot/sysroot my_crate.rs

Shell

These are a few functions that allow you to easily run rust code from the shell using cg_clif as jit.

function jit_naked() {
    echo "$@" | CG_CLIF_JIT=1 rustc -Zcodegen-backend=$cg_clif_dir/target/release/librustc_codegen_cranelift.so --sysroot $cg_clif_dir/build_sysroot/sysroot - -Cprefer-dynamic
}

function jit() {
    jit_naked "fn main() { $@ }"
}

function jit_calc() {
    jit 'println!("0x{:x}", ' $@ ');';
}

Env vars

CG_CLIF_JIT

Enable JIT mode to immediately run a program instead of writing an executable file.

CG_CLIF_JIT_ARGS

When JIT mode is enable pass these arguments to the program.

CG_CLIF_INCR_CACHE_DISABLED

Don't cache object files in the incremental cache. Useful during development of cg_clif to make it possible to use incremental mode for all analyses performed by rustc without caching object files when their content should have been changed by a change to cg_clif.

CG_CLIF_DISPLAY_CG_TIME

Display the time it took to perform codegen for a crate

Not yet supported

• Good non-rust abi support (several problems)
• Checked binops (some missing instructions in cranelift)
• Inline assembly (no cranelift support, not coming soon)
• SIMD (tracked here, some basic things work)