LDC cross-compilation for ARM GNU/Linux

This page will show you how to build a ldc cross-compiler for ARM architecture on GNU/Linux, so that you can build an executable binary with the druntime/phobos and run it on your ARM target.

Prerequisites

• Linux host, where you'll build and run ldc.
• C/C++ toolchain, to build llvm and parts of ldc.
• A pre-built D compiler for GNU/Linux, needed because the ldc frontend is written in D.
  • You can get the official dmd release for Linux or one of the ldc releases for Linux.
• Common development tools, such as CMake and git, and ldc uses libconfig++
• ldc/druntime/phobos source
• llvm 3.8 source, either from the official release or git.
• GNU ARM toolchain that supports your ARM target [1]
  • In this example, GNU ARM Embedded Toolchain 4.3.3-2009-q1 is used, installed on the host at /opt/arm-2009q1
• An ARM target with a running GNU/Linux installed on it (like an Ubuntu distribution installed on a Raspberry Pi)

Compile llvm

Get the source for llvm, either the latest official 3.8.0 release or a git repository, like this llvm mirror. Build llvm as you would normally, with the ARM target:

curl -O http://llvm.org/releases/3.8.0/llvm-3.8.0.src.tar.xz
tar xvf llvm-3.8.0.src.tar.xz
cd llvm-3.8.0.src/

mkdir llvm-3.8.0.arm_obj/
cd llvm-3.8.0.arm_obj/
cmake .. -DCMAKE_BUILD_TYPE=Release -DLLVM_TARGETS_TO_BUILD=ARM
make -j5

Build ldc for GNU/ARM

Clone the ldc repository, check out the release-1.0.0 branch, apply the patch for CMakeLists.txt, set the DMD environment variable to the path of your pre-built D compiler, and build ldc, druntime and phobos as usual:

cd ..
git clone --recursive https://github.com/ldc-developers/ldc.git
cd ldc/
git checkout -b ddmd origin/release-1.0.0
git submodule update
curl -O https://gist.githubusercontent.com/ldc_1.0.0_gnu_arm
git apply ldc_1.0.0_gnu_arm

mkdir build_arm
cd build_arm
export DMD=/path/to/your/dmd2/linux/bin64/dmd
cmake .. -DLLVM_CONFIG=../../llvm-3.8.0.arm_obj/bin/llvm-config
make druntime-ldc phobos2-ldc -j5

Build a command-line executable

Now that we have a D cross-compiler and cross-compiled the standard library for GNU/ARM, let's try building a small program, the classic Hello world:

./bin/ldc2 -v -mtriple=arm-none-linux-gnueabi -gcc=/opt/arm-2009q1/bin/arm-none-linux-gnueabi-gcc helloworld.d

Push and run this program on an ARM device with GNU/Linux

Directions for future work

• Run druntime and phobos unit-tests.