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Build from Source

Tip

Unless you really need to build Codon from source, it is strongly recommended to use pre-built binaries if possible.

Dependencies

Codon uses an LLVM fork based on LLVM 20. To build it, you can do the following:

git clone --depth 1 -b codon https://github.com/exaloop/llvm-project
cmake -S llvm-project/llvm -B llvm-project/build \
    -DCMAKE_BUILD_TYPE=Release \
    -DLLVM_INCLUDE_TESTS=OFF \
    -DLLVM_ENABLE_RTTI=ON \
    -DLLVM_ENABLE_ZLIB=OFF \
    -DLLVM_ENABLE_ZSTD=OFF \
    -DLLVM_ENABLE_PROJECTS="openmp" \
    -DLLVM_TARGETS_TO_BUILD=all
cmake --build llvm-project/build
cmake --install llvm-project/build --prefix=llvm-project/install

You can use -DLLVM_ENABLE_PROJECTS="clang;openmp" if you do not have clang installed on your system. We also recommend setting a local prefix during installation to avoid clashes with the system LLVM.

Build

Codon requires libgfortran, the parent directory of which must be specified via the CODON_SYSTEM_LIBRARIES environment variable. For example, on macOS, with a brew-installed libgfortran (obtainable via brew install gcc):

export CODON_SYSTEM_LIBRARIES=/opt/homebrew/opt/gcc/lib/gcc/current

On Linux:

export CODON_SYSTEM_LIBRARIES=/usr/lib/x86_64-linux-gnu

Then, the following can generally be used to build Codon. The build process will automatically download and build several smaller dependencies.

cd codon
mkdir build
cmake -S . -B build \
    -DCMAKE_BUILD_TYPE=Release \
    -DLLVM_DIR=$(llvm-config --cmakedir) \
    -DCMAKE_C_COMPILER=clang \
    -DCMAKE_CXX_COMPILER=clang++
cmake --build build --config Release
cmake --install build --prefix=install

This will produce the codon executable in the install/bin directory, as well as codon_test in the build directory which runs the test suite. Additionally, a number of shared libraries are produced in install/lib/codon:

  • libcodonc: The compiler library used by the codon command-line tool.
  • libcodonrt: The runtime library used during execution.
  • libomp: OpenMP runtime used to execute parallel code.

Warning

Make sure the llvm-config being used corresponds to Codon's LLVM. You can also use -DLLVM_DIR=llvm-project/install/lib/cmake/llvm on the first cmake command if you followed the instructions above for compiling LLVM.

Jupyter support

To enable Jupyter support, you will need to build the Jupyter plugin:

# Linux version:
cmake -S jupyter -B jupyter/build \
    -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_C_COMPILER=clang \
    -DCMAKE_CXX_COMPILER=clang++ \
    -DLLVM_DIR=$(llvm-config --cmakedir) \
    -DCODON_PATH=install \
    -DOPENSSL_ROOT_DIR=$(openssl version -d | cut -d' ' -f2 | tr -d '"') \
    -DOPENSSL_CRYPTO_LIBRARY=/usr/lib64/libssl.so \
    -DXEUS_USE_DYNAMIC_UUID=ON
# n.b. OPENSSL_CRYPTO_LIBRARY might differ on your system.

# On macOS, do this instead:
OPENSSL_ROOT_DIR=/usr/local/opt/openssl cmake -S jupyter -B jupyter/build \
    -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_C_COMPILER=clang \
    -DCMAKE_CXX_COMPILER=clang++ \
    -DLLVM_DIR=$(llvm-config --cmakedir) \
    -DCODON_PATH=install

# Then:
cmake --build jupyter/build
cmake --install jupyter/build