cil-mode is a major emacs mode for editing of Common Intermediate Language. It helps emacs to highlight CIL keywords and sets up the proper indentation for such files.
Here's a screenshot of cil-mode with gruber-darker-theme:
Simply add it to your init.el, for example like this:
(load "~/.emacs.d/3rd-party/cil-mode/cil-mode.el")