diff --git a/lisp/llvm-lib/llvm-act-on-file/act-on-llvm-source-file.el b/lisp/llvm-lib/llvm-act-on-file/act-on-llvm-source-file.el
new file mode 100644
index 0000000..6033b57
--- /dev/null
+++ b/lisp/llvm-lib/llvm-act-on-file/act-on-llvm-source-file.el
@@ -0,0 +1,43 @@
+;;; act-on-llvm-source-file.el ---  -*- lexical-binding: t -*-
+
+;; Copyright (C) 2023 Benson Chu
+
+;; Author: Benson Chu <bensonchu457@gmail.com>
+;; Created: [2023-01-19 10:52]
+
+;; This file is not part of GNU Emacs
+
+;; This program is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;;; Code:
+
+(defun ll/is-llvm-source-file (file)
+  (and (string= "cpp" (file-name-extension file))
+       (string-match-p ".*llvm-project.*" file)))
+
+(defun ll/act-on-llvm-source-file (file)
+  (let ((dir (lls/get-llvm-build-dir)))
+    (--> file
+         (list (format "touch %s" it)
+               (lls/ninja-build-tools dir (list (concat it "^")) t))
+         (string-join it " && ")
+         (compilation-start it nil
+                            (lambda (_)
+                              (format "*ninja-%s*"
+                                      (file-name-nondirectory file)))))))
+
+(provide 'act-on-llvm-source-file)
+;;; act-on-llvm-source-file.el ends here
diff --git a/lisp/llvm-lib/llvm-act-on-file/llvm-act-on-file.el b/lisp/llvm-lib/llvm-act-on-file/llvm-act-on-file.el
index 1762ded..35e0213 100644
--- a/lisp/llvm-lib/llvm-act-on-file/llvm-act-on-file.el
+++ b/lisp/llvm-lib/llvm-act-on-file/llvm-act-on-file.el
@@ -41,6 +41,8 @@
   (pcase (file-name-extension file)
     ((and _ (guard (ll/is-test-file file)))
      (ll/act-on-test-file file))
+    ((and _ (guard (ll/is-llvm-source-file file)))
+     (ll/act-on-llvm-source-file file))
     ("o" (ll/act-on-obj-file file))
     ("c" (ll/act-on-c-file file))
     ("ll" (ll/act-on-ll-file file))