deb http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu xenial main 
deb-src http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu xenial main
deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial main
deb-src http://apt.llvm.org/xenial/ llvm-toolchain-xenial main
deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-3.8 main
deb-src http://apt.llvm.org/xenial/ llvm-toolchain-xenial-3.8 main
deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-3.9 main
deb-src http://apt.llvm.org/xenial/ llvm-toolchain-xenial-3.9 main
deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-4.0 main
deb-src http://apt.llvm.org/xenial/ llvm-toolchain-xenial-4.0 main