编译llvm

wget http://releases.llvm.org/3.9.1/llvm-3.9.1.src.tar.xz
tar Jxvf llvm-3.9.1.src.tar.xz
cd llvm-3.9.1.src
mkdir build
cd build
cmake ..
make
make install

( from http://llvm.org/docs/CMake.html,下载地址：http://releases.llvm.org )