Development environment to hack on llvm/clang

shell.nix

with import <nixpkgs> {};
let
  gccForLibs = stdenv.cc.cc;
  libc_lib = getLib stdenv.cc.libc;
in stdenv.mkDerivation {
  name = "env";
  buildInputs = [
    bashInteractive
    ninja
    cmake
    llvmPackages_latest.llvm
  ];

  # where to find libgcc
  NIX_LDFLAGS="-L${gccForLibs}/lib/gcc/${targetPlatform.config}/${gccForLibs.version}";
  # teach clang about C startup file locations
  CFLAGS="-B${gccForLibs}/lib/gcc/${targetPlatform.config}/${gccForLibs.version} -B ${stdenv.cc.libc}/lib";

  cmakeFlags = [
    "-DGCC_INSTALL_PREFIX=${gcc}"
    "-DC_INCLUDE_DIRS=${stdenv.cc.libc.dev}/include"
    "-GNinja"
    "-DCMAKE_BUILD_TYPE=Release"
    "-DCMAKE_INSTALL_PREFIX=../inst"
    "-DLLVM_INSTALL_TOOLCHAIN_ONLY=ON"
    "-DLLVM_ENABLE_PROJECTS=clang;libcxx;libcxxabi"
    "-DLLVM_TARGETS_TO_BUILD=host"
  ];
  ## How to use with clang
  # $ git clone https://github.com/llvm/llvm-project/
  # $ mkdir build && cd build
  # $ cmake $cmakeFlags ../llvm-project/llvm
  # $ ninja && ninja install
  # $ cd ..
  ## assuming main.c is a test program.
  # ./inst/bin/clang $CFLAGS -o main main.c 
}