89a18cb600
Like we have `add`/`sub` which are the `usize` version of `offset`, this adds the `usize` equivalent of `offset_from`. Like how `.add(d)` replaced a whole bunch of `.offset(d as isize)`, you can see from the changes here that it's fairly common that code actually knows the order between the pointers and *wants* a `usize`, not an `isize`. As a bonus, this can do `sub nuw`+`udiv exact`, rather than `sub`+`sdiv exact`, which can be optimized slightly better because it doesn't have to worry about negatives. That's why the slice iterators weren't using `offset_from`, though I haven't updated that code in this PR because slices are so perf-critical that I'll do it as its own change. This is an intrinsic, like `offset_from`, so that it can eventually be allowed in CTFE. It also allows checking the extra safety condition -- see the test confirming that CTFE catches it if you pass the pointers in the wrong order. |
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| .. | ||
| .github/workflows | ||
| .vscode | ||
| build_sysroot | ||
| build_system | ||
| docs | ||
| example | ||
| patches | ||
| scripts | ||
| src | ||
| .cirrus.yml | ||
| .gitattributes | ||
| .gitignore | ||
| Cargo.lock | ||
| Cargo.toml | ||
| clean_all.sh | ||
| config.txt | ||
| LICENSE-APACHE | ||
| LICENSE-MIT | ||
| Readme.md | ||
| rust-toolchain | ||
| rustfmt.toml | ||
| test.sh | ||
| y.rs | ||
Cranelift codegen backend for rust
The goal of this project is to create an alternative codegen backend for the rust compiler based on 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
$ git clone https://github.com/bjorn3/rustc_codegen_cranelift.git
$ cd rustc_codegen_cranelift
$ ./y.rs prepare # download and patch sysroot src and install hyperfine for benchmarking
$ ./y.rs build
To run the test suite replace the last command with:
$ ./test.sh
This will implicitly build cg_clif too. Both y.rs build 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.
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 (y.rs prepare and y.rs build or test.sh).
In the directory with your project (where you can do the usual cargo build), run:
$ $cg_clif_dir/build/cargo-clif 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 usage.md.
Configuration
See the documentation on the BackendConfig struct in config.rs for all
configuration options.
Not yet supported
- Inline assembly (no cranelift support)
- On Linux there is support for invoking an external assembler for
global_asm!andasm!.llvm_asm!will remain unimplemented forever.asm!doesn't yet support reg classes. You have to specify specific registers instead.
- On Linux there is support for invoking an external assembler for
- SIMD (tracked here, some basic things work)
License
Licensed under either of
- Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you shall be dual licensed as above, without any additional terms or conditions.