In this post we’ll setup Clang for out-of-the-tree development (3.9.0).

HOW TO

I assume that clang/llvm is already compiled from source and it is installed as we covered in building llvm with cmake. Lets assume that the path for the llvm installation is $HOME/opt/llvm. Make sure you exported the following env to the shell:

VERSION=3.9.0
export LLVM_HOME=$HOME/opt/llvm
export PATH=$LLVM_HOME/bin:$PATH
export C_INCLUDE_PATH=$LLVM_HOME/include:$LLVM_HOME/lib/clang/$VERSION/include:$C_INCLUDE_PATH
export CPLUS_INCLUDE_PATH=$LLVM_HOME/include:$LLVM_HOME/lib/clang/$VERSION/include:$LLVM_HOME/include/c++/v1:$CPLUS_INCLUDE_PATH
export LIBRARY_PATH=$LLVM_HOME/lib:$LIBRARY_PATH
export DYLD_LIBRARY_PATH=$LLVM_HOME/lib:$DYLD_LIBRARY_PATH

Clone the Clang repo.

I forked the clang repo hosted in github.com/llvm-mirror. You can either clone the repo or fork it.

Since I intent to modify the source code, I located the cloned folder in my preferred location for programming projects (lets say it is at $HOME/Dev/clang_dev).

Adding script to compile the project using cmake and ninja

I created a simple bash script that runs cmake to prepare for compilation and runs ninja for compiling the files. You need to replace $PATH_TO_INSTALL with the location of your choice.

#!/bin/bash
if [ -z "$1" ]; then
    echo "USAGE: compile.sh <phase> <dry_run>. It can be cmake, ninja_build, ninja_install"
    exit -1
fi
phase=$1
dry_run=""
TARGET_SRC=$PWD
TARGET_BUILD=$TARGET_SRC/../clang_dev_build
TARGET_INSTALL=$PATH_TO_INSTALL
if [ "$#" -ge "2" ]; then
    dry_run="-n"
fi
mkdir $TARGET_BUILD
echo Changing folders to $TARGET_BUILD...
cd $TARGET_BUILD
echo We\'re at $PWD
if [ "$phase" == "cmake" ]; then
  cmake $TARGET_SRC -G "Eclipse CDT4 - Ninja" -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_BUILD_TYPE="Release" -DCMAKE_INSTALL_PREFIX=$TARGET_INSTALL 
fi
if [ "$phase" == "ninja_build" ]; then
  ninja $dry_run
fi
if [ "$phase" == "ninja_install" ]; then
  ninja install $dry_run -v
fi

Tested with…

  • OSX 10.11.6
  • Compiled with LLVM version 3.9.0 compiled from source code.
  • cmake 3.6.2
  • ninja 1.7.1