cargo-sysroot 0.5.0

Simply and Easily cross-compile the Rust sysroot crates.
cargo-sysroot-0.5.0 is not a library.
Visit the last successful build: cargo-sysroot-0.8.1

Cargo-sysroot

Crates.io maintenance-as-is

A (dumb) tool to compile libcore and friends for no_std crates.

This is not a wrapper like cargo xbuild or xargo, this is a standalone tool you call once. This has the nice benefit of actually working with standard tools like RLS, clippy, or even the simple cargo check.

New in 0.5.0

Support for the new sysroot build process, and more reliable overall.

Liballoc!

I'm no longer mysterious!

Prerequisite

  • A nightly compiler.
  • The rust-src component must be installed for the active toolchain.
  • Your Cargo.toml file must contain package.metadata.cargo-sysroot.target, where target is a target specifiction json file.
    • A rust supported target may also work, but this is untested.
  • OR Pass --target on the commandline, ex cargo sysroot --target path/to/target.json

Example Cargo.toml

[package]
name = "My Project"
version = "0.1.0"
authors = ["Me <Me@Me.com>"]

[package.metadata.cargo-sysroot]
target = "my_custom_target.json" # This is relative to Cargo.toml

Getting Started

  • Run cargo install cargo-sysroot.
  • Run cargo sysroot in the working directory of your project.

This tool will generate a .cargo/config for you that looks something like this

[build]
target = "path/to/your/target/specification/json"
rustflags = [
    "--sysroot",
    "full/path/to/target/sysroot",
]

The sysroot will be located at target/sysroot and the target directory for building it at target/sysroot/target.

Due to how rust sysroots work, you can use multiple different target specifications at a time without rebuilding. Switching between them will require manually changing .cargo/config, however.

Note that this tool is currently quite stupid, so it won't attempt to do anything if that file already exists. In this case you will have to edit it manually.

This will allow Cargo to properly build your project with the normal commands such as cargo build. You may wish to modify this file to make use of the target.$triple.runner key. See the Cargo Documentation for details. Note that the author experienced problems with the $triple variant not working, and you may experience better success with the cfg variant.

If you update your Rust nightly version you will need to run cargo-sysroot again. Note that doing this will cause cargo to detect that libcore has changed and rebuild your entire project.

Recomendations

If you have more complicated needs than can be satisfied by target.$triple.runner, which doesn't yet support passing arguments, the author recommends using a tool such as cargo-make.

Details

The sysroot crates are compiled with the --release switch. compilter_builtins is built with the mem and core features, which provides memcpy and related.

TODO

  • Allow specifying a custom rust-src.
  • Allow disabling the mem feature.

FAQ

  • Q: Why are all versions before 0.5.0 yanked?

  • A: They didn't work correctly due to bugs or changes in the standard distribution.

  • Q: Why did you write this over just using cargo-xbuild

  • A: It was easier and simpler than getting cargo-xbuild to work reliably or with any other standard tools.

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, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.