hexagon-unknown-linux-musl

Tier: 3

Target for cross-compiling Linux user-mode applications targeting the Hexagon DSP architecture.

Target maintainers

• Brian Cain, bcain@quicinc.com

Requirements

The target is cross-compiled. This target supports std. By default, code generated with this target should run on Hexagon DSP hardware.

• -Ctarget-cpu=hexagonv73 adds support for instructions defined up to Hexagon V73.

Binaries can be run using QEMU user emulation. On Debian-based systems, it should be sufficient to install the package qemu-user-static to be able to run simple static binaries:

# apt install qemu-user-static
# qemu-hexagon-static ./hello

In order to build linux programs with Rust, you will require a linker capable of targeting hexagon. You can use clang/lld from the hexagon toolchain using exclusively public open source repos.

Also included in that toolchain is the C library that can be used when creating dynamically linked executables.

# /opt/clang+llvm-18.1.0-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/bin/qemu-hexagon -L /opt/clang+llvm-18.1.0-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/target/hexagon-unknown-linux-musl/usr/ ./hello

Building the target

Because it is Tier 3, rust does not yet ship pre-compiled artifacts for this target.

Therefore, you can build Rust with support for the target by adding it to the target list in config.toml, a sample configuration is shown below.

[build]
target = ["hexagon-unknown-linux-musl"]

[target.hexagon-unknown-linux-musl]

cc = "hexagon-unknown-linux-musl-clang"
cxx = "hexagon-unknown-linux-musl-clang++"
linker = "hexagon-unknown-linux-musl-clang"
ar = "hexagon-unknown-linux-musl-ar"
ranlib = "hexagon-unknown-linux-musl-ranlib"
musl-root = "/opt/clang+llvm-18.1.0-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/target/hexagon-unknown-linux-musl/usr"
llvm-libunwind = 'in-tree'
qemu-rootfs = "/opt/clang+llvm-18.1.0-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/target/hexagon-unknown-linux-musl/usr"

Testing

Currently there is no support to run the rustc test suite for this target.

Building Rust programs

Download and install the hexagon open source toolchain from https://github.com/quic/toolchain_for_hexagon/releases

The following .cargo/config is needed inside any project directory to build for the Hexagon Linux target:

[build]
target = "hexagon-unknown-linux-musl"

[target.hexagon-unknown-linux-musl]
linker = "hexagon-unknown-linux-musl-clang"
ar = "hexagon-unknown-linux-musl-ar"
runner = "qemu-hexagon -L /opt/clang+llvm-18.1.0-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/target/hexagon-unknown-linux-musl/usr"

Edit the "runner" in .cargo/config to point to the path to your toolchain's C library.

...
runner = "qemu-hexagon -L /path/to/my/inst/clang+llvm-18.1.0-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/target/hexagon-unknown-linux-musl/usr"
...

Build/run your rust program with qemu-hexagon in your PATH:

export PATH=/path/to/my/inst/clang+llvm-18.1.0-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/bin/:$PATH
cargo run -Zbuild-std -Zbuild-std-features=llvm-libunwind