Cargo-xbuild is a wrapper for
cargo build, which cross compiles the sysroot crates
alloc for custom targets. It is a simplified fork of
xargo, which is in maintainance mode.
rust-srccomponent, which you can install with
rustup component add rust-src.
Rust and Cargo.
$ cargo install cargo-xbuild
Note: The latest version of
cargo-xbuild supports all nightlies after 2019-02-04. If you are on an older nightly, you need to install version 0.5.4:
cargo install cargo-xbuild --version 0.5.4.
cargo xbuild instead of
cargo build when cross-compiling for a custom target.
cargo xbuild --target your-target-name.json
Instead of the "can't find crate for
core" error you would get with a plain
cargo build, this crate cross-compiles the
alloc crates and then invokes
cargo build with a modified sysroot. The sysroot is compiled in the
target directory of your crate.
All additional arguments (e.g.
--verbose) are forwarded to
cargo-xbuild create a
package.metadata.cargo-xbuild table in your
Cargo.toml. The following options are available:
[package.metadata.cargo-xbuild] memcpy = true sysroot_path = "target/sysroot"
memcpyflag defines whether the
memfeature of the
compiler_builtinscrate should be activated. Turning this flag off allows to specify own versions of the
sysroot_pathflag specifies the directory where the sysroot should be placed.
In addition to the above configuration keys,
cargo-xbuild can be also configured through the following environment variables:
XBUILD_SYSROOT_PATHvariable can be used to specify where
cargo-xbuildshould place the generated sysroot. This variables takes precendence over the
If you want to use a local Rust source instead of
rust-src rustup component, you can set the
XARGO_RUST_SRC environment variable.
# The source of the `core` crate must be in `$XARGO_RUST_SRC/libcore` $ export XARGO_RUST_SRC=/path/to/rust/src $ cargo xbuild --target msp430-none-elf.json
Using on Android
It's possible to run cargo-xbuild on your Android phone:
Install Termux and Nightly Rustc
- Install termux
- Install fish shell and set as default (optional):
pkg install fish; chsh -s fish; fish
- Install some basic tools:
pkg install wget tar
- Add the community repository by its-pointless:
wget https://its-pointless.github.io/setup-pointless-repo.sh; bash setup-pointless-repo.sh
- Install rust nightly:
pkg install rustc cargo rustc-nightly
- Prepend the nightly rustc path to your
$PATHin order to use nightly (fish syntax):
set -U fish_user_paths $PREFIX/opt/rust-nightly/bin/ $fish_user_paths
rustc --versionshould now return a nightly version
(Optional) Install Git and Clone your Repository
- Install git:
pkg install git
- Clone a repository of your choice:
git clone https://github.com/phil-opp/blog_os.git
- Install cargo-xbuild:
cargo install cargo-xbuild
- Add the cargo bin directory to your
set -U fish_user_paths ~/.cargo/bin/ $fish_user_paths
cargo xbuildshould be available.
It does not work yet because it needs access to the rust source code. By default it tries to use rustup for this, but we have no rustup support so we need a different way.
Providing the Rust Source Code
The Rust source code corresponding to our installed nightly is available in the
- Download it:
- Extract it:
tar xf rust-src-nightly.tar.xz
- Set the
XARGO_RUST_SRCenvironment variable to tell cargo-xbuild the source path (fish syntax):
set -Ux XARGO_RUST_SRC ~/rust-src-nightly/rust-src/lib/rustlib/src/rust/src
Now cargo-xbuild should no longer complain about a missing
rust-src component. However it will throw an I/O error after building the sysroot. The problem is that the downloaded Rust source code has a different structure than the source provided by rustup. We can fix this by adding a symbolic link:
ln -s ~/../usr/opt/rust-nightly/bin ~/../usr/opt/rust-nightly/lib/rustlib/aarch64-linux-android/bin
cargo xbuild --target your-target.json should work!
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.
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.