5p4k/rpi-cross repository overview

⁠Raspberry Pi cross-compile images (unofficial)

Official repo: https://git.mittelab.org/5p4k/rpi-build-tools⁠

A set of x86_64 (no need for QEMU) images with the basic compiling tools and a minimal sysroot for Raspbian, to cross-compile for the Raspberry Pi (in armv6, so runs also on the RPi 1). Binaries compiled with this image can be directly copied to the Raspberry Pi. The sysroot for Raspbian is generated directly by extracting the essential .deb packages from Raspbian, to keep it as small as possible. Unneeded files such as executables are removed from the sysroot.

• latest, buster, buster-on-alpine Alpine-based (3.11.5, Clang 9) cross-compile image for Raspbian Buster (~80MB)
• stretch, stretch-on-alpine Alpine-based (3.11.5, Clang 9) cross-compile image for Raspbian Stretch (~80MB)
• buster-on-debian Debian-based (buster-slim, Clang 7) cross-compile image for Raspbian Buster (~200MB)
• stretch-on-debian Debian-based (buster-slim, Clang 7) cross-compile image for Raspbian Stretch (~200MB)

Images come in two flavours:

• Alpine⁠ based, currently 3.11.5 Currently the smaller image (~80MB), cross-compiles using the shipped Clang 9.
• Debian⁠ based, currently buster-slim Currently ~200MB, cross-compiles using the shipped Clang 7.

Choose the image tag based on the version of Raspbian you're compiling for:

• docker pull 5p4k/rpi-cross:buster
• docker pull 5p4k/rpi-cross:stretch

⁠Usage with CMake

Specify -DCMAKE_TOOLCHAIN_FILE=/usr/share/RPi.cmake when calling CMake.

$ docker run -it --rm -v /path/to/project:/mnt 5p4k/rpi-cross:buster
# cd /mnt
# mkdir build_folder
# cd build_folder
# cmake -DCMAKE_TOOLCHAIN_FILE=/usr/share/rpi-sysroot/RPi.cmake ..
# make
# exit

⁠Usage when compiling directly

Use the wrappers cc- and cpp-armv6-linux-gnueabihf instead of cc and c++.

$ docker run -it --rm -v /path/to/project:/mnt 5p4k/rpi-cross:buster
# cd /mnt
# cpp-armv6-linux-gnueabihf my_source_file.cpp
ld: warning: lld uses extended branch encoding, no object with architecture supporting feature detected.
ld: warning: lld may use movt/movw, no object with architecture supporting feature detected.
# ./a.out   # Will fail because can only run on a Raspberry Pi
/lib/ld-linux-armhf.so.3: No such file or directory
# exit

⁠What's in the image

• /usr/share/RPi.cmake CMake toolchain for cross-compilation.
• /usr/share/rpi-sysroot Sysroot from RPi cross-compilation.
• /usr/share/rpi-sysroot/check-armv6 Checks that the sysroot contains only armv6 binaries.
• /usr/bin/cc-armv6-linux-gnueabihf Cross-compile wrapper for the C compiler.
• /usr/bin/cpp-armv6-linux-gnueabihf Cross-compile wrapper for the C++ compiler.
• /usr/bin/arch-check Checks the architecture of a binary.

⁠Packages in the sysroot

Buster: gcc-8-base, libc-bin, libc-dev-bin, libc6-dev, libc6, libgcc-8-dev, libgcc1, libgomp1, libstdc++-8-dev, libstdc++6, linux-libc-dev, libc++-8-dev, libc++1-8, libc++abi-8-dev, libc++abi1-8

Stretch: gcc-4.7-base, libc-bin, libc-dev-bin, libc6-dev, libc6, libgcc-4.7-dev, libgcc1, libgomp1, libstdc++6-4.7-dev, libstdc++6, linux-libc-dev, libc++1, libc++-dev, libc++abi1, libc++abi-dev