*-unknown-helenos
Tier: 3
Targets for HelenOS. These targets allow compiling user-space applications, that you can then copy into your HelenOS ISO image to run them.
Target triplets available:
x86_64-unknown-helenossparc64-unknown-helenospowerpc-unknown-helenosaarch64-unknown-helenosi686-unknown-helenos*
On i686, some portions of native HelenOS libraries run into issues due to vector instructions accessing variables from the stack that seems
to be misaligned. It is not clear if this is fault of HelenOS or Rust. Most programs work, but for example calling ui_window_create from HelenOS
libui does not work.
Target maintainers
- Matěj Volf (@mvolfik)
Requirements
These targets only support cross-compilation. The targets will1 support libstd, although support of some platform features (filesystem, networking) may be limited.
You need to have a local clone of the HelenOS repository and the HelenOS toolchain set up, no HelenOS-Rust development artifacts are available.
Building
If you want to avoid the full setup, fully automated Docker-based build system is available at https://github.com/mvolfik/helenos-rust-autobuild
HelenOS toolchain setup
For compilation of standard library, you need to build the HelenOS toolchain (because Rust needs to use *-helenos-gcc as linker) and its libraries (libc and a few others). See this HelenOS wiki page for instruction on setting up the build. At the end of step 4 (Configure and build), after ninja image_path, invoke ninja export-dev to build the shared libraries.
Copy the libraries to the path where the compiler automatically searches for them. This will be the directory where you installed the toolchain (for example ~/.local/share/HelenOS/cross/i686-helenos/lib). In the folder where you built HelenOS, you can run these commands:
touch /tmp/test.c
HELENOS_LIB_PATH="$(realpath "$(amd64-helenos-gcc -v -c /tmp/test.c 2>&1 | grep LIBRARY_PATH | cut -d= -f2 | cut -d: -f2)")"
# use sparc64-helenos-gcc above for the SPARC toolchain, etc
cp -P export-dev/lib/* "$HELENOS_LIB_PATH"
Building the target
When you have the HelenOS toolchain set up and installed in your path, you can build the Rust toolchain using the standard procedure. See rustc dev guide.
In the most simple case, this means that you can run ./x build library --stage 1 --target x86_64-unknown-linux-gnu,<arch>-unknown-helenos (the first target triple should be your host machine, adjust accordingly). Then run rustup toolchain link mytoolchain build/host/stage1 to allow using your toolchain for building Rust programs.
Building Rust programs
If you linked the toolchain above as mytoolchain, run cargo +mytoolchain build --target <arch>-unknown-helenos.
Testing
After you build a Rust program for HelenOS, you can put it into the dist directory of the HelenOS build, build the ISO image, and then run it either in an emulator, or on real hardware. See HelenOS wiki for further instructions on running the OS.
Running the Rust testsuite has not been attempted yet due to missing host tools (thus the test suite can't be run natively) and insufficient networking support (thus we can't use the remote-test-server tool).
Cross-compilation toolchains and C code
You should be able to cross-compile and link any needed C code using <arch>-helenos-gcc that you built above. However, note that clang support is highly lacking. Therefore, to run tools such as bindgen, you will need to provide flag -nostdinc and manually specify the include paths to HelenOS headers, which you will find in the export-dev folder + in the cross-compilation toolchain (e.g. ~/.local/share/HelenOS/cross/lib/gcc/i686-helenos/14.2.0/include). You can see an example of proper build.rs at https://github.com/mvolfik/helenos-ui-rs/blob/master/build.rs
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libstd is not yet available, because it needs to be done in a separate PR, because compiler support needs to be merged first to allow creating libc bindings ↩