Implement Git hook for clang-formatting

.githooks/pre-commit

@@ -12,11 +12,24 @@ readarray -d '' files < <(
     | grep -zE '\.py$' \
     | grep -zEv '^(llvm-project/|external/llvm-project/)'
 )
+
 if (( ${#files[@]} )); then
-    echo "Running yapf on ${#files[@]} files..."
-    yapf -i "${files[@]}"
-    echo "Staging changes..."
-    git add -- "${files[@]}"
+    if command -v yapf >/dev/null 2>&1; then
+        echo "Running yapf on ${#files[@]} files..."
+        yapf -i "${files[@]}"
+        echo "Staging changes..."
+        git add -- "${files[@]}"
+    else
+        echo "yapf not found, skipping Python formatting."
+    fi
+fi
+
+echo "Running clang-format on C/C++ files..."
+cd "$(git rev-parse --show-toplevel)"
+if ! python3 mlir/utils/widgets/clangformat.py -q -i HEAD; then
+    echo "clang-format failed; aborting commit." >&2
+    (( NEED_POP )) && git stash pop -q || true
+    exit 1
 fi
 
 if (( NEED_POP )); then

mlir/utils/widgets/clangformat.py

@@ -0,0 +1,105 @@
+#####################################################################################
+# The MIT License (MIT)
+#
+# Copyright (c) 2015-2025 Advanced Micro Devices, Inc. All rights reserved.
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#####################################################################################
+import os
+import argparse
+import subprocess
+
+CLANG_FORMAT_PATH = '/opt/rocm/llvm/bin'
+EXCLUDE_FILES = ['requirements.in', 'onnx.proto']
+CLANG_EXTENSIONS = ('.c', '.cpp', '.hpp', '.h', '.cl', '.hip', '.in')
+
+
+def is_excluded(f):
+    base = os.path.basename(f)
+    return base in EXCLUDE_FILES
+
+
+def get_top():
+    return subprocess.check_output(['git', 'rev-parse', '--show-toplevel'],
+                                   text=True).strip()
+
+
+def get_merge_base(against):
+    return subprocess.check_output(['git', 'merge-base', against, 'HEAD'],
+                                   text=True).strip()
+
+
+def get_changed_files(base):
+    output = subprocess.check_output(['git', 'diff', '--name-only', base],
+                                     text=True)
+    return [f.strip() for f in output.splitlines() if f.strip()]
+
+
+def run(cmd, cwd=None, verbose=False):
+    if verbose:
+        print("Running:", " ".join(cmd))
+    subprocess.run(cmd, cwd=cwd, check=True)
+
+
+def clang_format(against, apply=False, path=CLANG_FORMAT_PATH):
+    base = get_merge_base(against)
+    clang_format = os.path.join(path, 'clang-format')
+    if not os.path.exists(clang_format):
+        print(f"{clang_format} not installed. Skipping format.")
+        return
+    git_clang_format = os.path.join(path, 'git-clang-format')
+    if not os.path.exists(git_clang_format):
+        print(f"{git_clang_format} not installed. Skipping format.")
+        return
+    diff_flag = [] if apply else ["--diff"]
+    files = get_changed_files(base)
+    files = [
+        f for f in files if f.endswith(CLANG_EXTENSIONS) and not is_excluded(f)
+    ]
+    if not files:
+        print("No files to format.")
+        return
+    run([git_clang_format, '--binary', clang_format] + diff_flag + [base] +
+        files,
+        cwd=get_top(),
+        verbose=True)
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('against', default='develop', nargs='?')
+    parser.add_argument('-i', '--in-place', action='store_true')
+    parser.add_argument('-q', '--quiet', action='store_true')
+    args = parser.parse_args()
+    try:
+        clang_format(args.against, apply=args.in_place)
+    except subprocess.CalledProcessError as ex:
+        if ex.stdout:
+            print(ex.stdout)
+        if ex.stderr:
+            print(ex.stderr)
+        if not args.quiet:
+            print(f"Command '{ex.cmd}' returned {ex.returncode}")
+        raise
+    return 0
+
+
+if __name__ == "__main__":
+    import sys
+    sys.exit(main())