bash-completion.sh

# Please add "source /path/to/bash-autocomplete.sh" to your .bashrc to use this.
_clang()
{
  local cur prev words cword arg
  _init_completion -n : || return

  local w1="${COMP_WORDS[$cword - 1]}"
  local w2="${COMP_WORDS[$cword - 2]}"
  if [[ "$cur" == -* ]]; then
    # -foo<tab>
    arg="$cur"
  elif [[ "$w1" == -*  && "$cur" == '=' ]]; then
    # -foo=<tab>
    arg="$w1=,"
  elif [[ "$w1" == -* ]]; then
    # -foo <tab> or -foo bar<tab>
    arg="$w1,$cur"
  elif [[ "$w2" == -* && "$w1" == '=' ]]; then
    # -foo=bar<tab>
    arg="$w2=,$cur"
  else
    _filedir
  fi

  flags=$( /home/yamaguchi/test-build/bin/clang-5.0 --autocomplete="$arg" )
  if [[ "$cur" == "=" ]]; then
    COMPREPLY=( $( compgen -W "$flags" -- "") )
  elif [[ "$flags" == "" ]]; then
    _filedir
  else
    if [[ ${flags: -1} == "=" ]]; then
      compopt -o nospace
    fi
    COMPREPLY=( $( compgen -W "$flags" -- "$cur" ) )
  fi
}
complete -F _clang clang