[clang-tidy] Allow clang-tidy on generated sources.

Adds an opt-in mode for clang-tidy to process generated sources.

By default, clang-tidy keeps the current behavior and skips sources from the build root. With `-DTIDY_ALLOW_GENERATED=yes`, the generated `clang_tidy.py` command receives `--allow-generated-sources` and does not skip those files.
commit_hash:7d7939f1fd226722c2a6a07a48ea025194897c73

2 files changed, 17 insertions, 2 deletions

diff --git a/build/scripts/clang_tidy.py b/build/scripts/clang_tidy.py
index 525518d891e..1e08a7bb688 100644
--- a/build/scripts/clang_tidy.py
+++ b/build/scripts/clang_tidy.py
@@ -43,6 +43,7 @@ def parse_args():
     parser.add_argument("--checks", required=False, default="")
     parser.add_argument("--header-filter", required=False, default=None)
     parser.add_argument("--collect-build-volume", action="store_true")
+    parser.add_argument("--allow-generated-sources", action="store_true")
     return parser.parse_known_args()
 
 
@@ -104,6 +105,13 @@ def is_generated(testing_src, build_root):
     return testing_src.startswith(build_root)
 
 
+def source_relative_path(testing_src, source_root, build_root):
+    if is_generated(testing_src, build_root):
+        return os.path.relpath(testing_src, build_root)
+
+    return os.path.relpath(testing_src, source_root)
+
+
 def generate_outputs(output_json):
     output_obj = os.path.splitext(output_json)[0] + ".o"
     open(output_obj, "w").close()
@@ -177,7 +185,7 @@ def main():
     clang_tidy_bin = args.clang_tidy_bin
     output_json = args.tidy_json
     generate_outputs(output_json)
-    if is_generated(args.testing_src, args.build_root):
+    if is_generated(args.testing_src, args.build_root) and not args.allow_generated_sources:
         return
     if args.header_filter is None:
         # .pb.h files will be excluded because they are not in source_root
@@ -259,7 +267,11 @@ def main():
         build_volume = load_build_volume(statistics_file)
         if build_volume is not None:
             profile[BUILD_VOLUME_PROFILE_KEY] = build_volume
-    testing_src = os.path.relpath(args.testing_src, args.source_root)
+    testing_src = source_relative_path(
+        testing_src=args.testing_src,
+        source_root=args.source_root,
+        build_root=args.build_root,
+    )
     tidy_fixes = load_fixes(fixes_file)
 
     with open(output_json, "wt") as afile:
diff --git a/build/ymake.core.conf b/build/ymake.core.conf
index 0dde5d83acd..0fda05cdb61 100644
--- a/build/ymake.core.conf
+++ b/build/ymake.core.conf
@@ -238,6 +238,9 @@ when ($TIDY_ENABLED == "yes") {
     }
 
     CPP_ANALYSIS_ARGS+="--collect-build-volume"
+    when ($TIDY_ALLOW_GENERATED == "yes") {
+        CPP_ANALYSIS_ARGS+="--allow-generated-sources"
+    }
 
     when ($TIDY_HEADER_FILTER) {
         CPP_ANALYSIS_ARGS+="--header-filter=$TIDY_HEADER_FILTER"