crossdev

🌍 multiarch cross compiling environment

This is a multiarch Docker build environment image. You can use this image to produce binaries for multiple architectures.

It leverages multiple of the multiarch family of projects:

• qemu-user-static
• crossbuild
• debian-debootstrap

This project leverages distcc for efficient compilation across a wide variety of architectures. A QEMU architecture specific docker environment is used as a master node, managing any external package dependencies via the distro's package manager. A second docker environment is used to host the cross-compiler to natively compile code.

Why & How?

• Huge performance savings and better management of dependencies.

• Header resolution and library linking done locally inside of QEMU.

• Build doesn't have to be cross-compile aware, or configured for cross-compiling. As far as the build is concerned, it's building natively.

• The distcc in a nutshell: When told to compile .c files to .o files it (1) calls the preprocessor on each .c file (gcc -E) to resolve the includes (2) sends the preprocessed .c file through the network to a server (3) server compiles preprocessed .c code into .o object code (4) sends the .o file back when done (5) copies .o file back through network to local filesystem (6) calls the local compiler to link the .o files together

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Prerequisites

Register qemu-*-static for all supported processors except the current one

• ./setup_prereq.sh

Register shell helper functions for simplified use. Add the following to your .bashrc:

• . pwd/docker-cross.rc

Setup

export DOCKER_CROSS_PATH=/path/to/mount/in/container

Run

Start the build_container by navigating to the crossbuild directory and running docker-compose up. Next, navigate to the desired architecture and run docker-compose up. You may then use the docker-cross-run command from the docker-cross.rc to run commands inside of the container.

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Examples

Hello World

From the specific architecture folder:

$ export DOCKER_CROSS_PATH=$(readlink -f ..)
$ export DOCKER_CROSS_ENTRY_PATH=$(readlink -f ../crossbuild)
$ docker-compose up

Option 1

In another shell:

$ docker exec -it run_container_arm /bin/bash

This will open a shell inside of the run_container.

$ cd /workdir/helloworld

To use the build_container use the following:

$ DISTCC_VERBOSE=1 CC=/usr/lib/distcc/arm-linux-gnueabihf-gcc make

Otherwise, if it's a simple enough program then you can build inside of the run_container directly without distcc.

Option 2

In another shell:

$ docker-cross-run cd /workdir/helloworld && make

GDB Debugging

docker-cross-run gdbserver :2000 <your_binary>