rust/compiler/rustc_codegen_cranelift
bors 8c6ce6b91b Auto merge of #97802 - Enselic:add-no_ignore_sigkill-feature, r=joshtriplett
Support `#[unix_sigpipe = "inherit|sig_dfl"]` on `fn main()` to prevent ignoring `SIGPIPE`

When enabled, programs don't have to explicitly handle `ErrorKind::BrokenPipe` any longer. Currently, the program

```rust
fn main() { loop { println!("hello world"); } }
```

will print an error if used with a short-lived pipe, e.g.

    % ./main | head -n 1
    hello world
    thread 'main' panicked at 'failed printing to stdout: Broken pipe (os error 32)', library/std/src/io/stdio.rs:1016:9
    note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

by enabling `#[unix_sigpipe = "sig_dfl"]` like this

```rust
#![feature(unix_sigpipe)]
#[unix_sigpipe = "sig_dfl"]
fn main() { loop { println!("hello world"); } }
```

there is no error, because `SIGPIPE` will not be ignored and thus the program will be killed appropriately:

    % ./main | head -n 1
    hello world

The current libstd behaviour of ignoring `SIGPIPE` before `fn main()` can be explicitly requested by using `#[unix_sigpipe = "sig_ign"]`.

With `#[unix_sigpipe = "inherit"]`, no change at all is made to `SIGPIPE`, which typically means the behaviour will be the same as `#[unix_sigpipe = "sig_dfl"]`.

See https://github.com/rust-lang/rust/issues/62569 and referenced issues for discussions regarding the `SIGPIPE` problem itself

See the [this](https://rust-lang.zulipchat.com/#narrow/stream/219381-t-libs/topic/Proposal.3A.20First.20step.20towards.20solving.20the.20SIGPIPE.20problem) Zulip topic for more discussions, including about this PR.

Tracking issue: https://github.com/rust-lang/rust/issues/97889
2022-09-02 21:08:08 +00:00
..
.github/workflows
.vscode
build_sysroot
build_system
docs
example
patches
scripts
src Auto merge of #97802 - Enselic:add-no_ignore_sigkill-feature, r=joshtriplett 2022-09-02 21:08:08 +00:00
.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 UNIX there is support for invoking an external assembler for global_asm! and asm!.
  • SIMD (tracked here, some basic things work)

License

Licensed under either of

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.