Optionally pass --gcc-install-dir option to clang

BUILD

@@ -33,3 +33,14 @@ label_flag(
     build_setting_default = ":clang_tidy_additional_deps_default",
     visibility = ["//visibility:public"],
 )
+
+filegroup(
+    name = "clang_tidy_gcc_install_dir_default",
+    srcs = [],
+)
+
+label_flag(
+    name = "clang_tidy_gcc_install_dir",
+    build_setting_default = ":clang_tidy_gcc_install_dir_default",
+    visibility = ["//visibility:public"],
+)

README.md

@@ -85,6 +85,40 @@ build:clang-tidy --@bazel_clang_tidy//:clang_tidy_executable=@local_config_cc//:
 This aspect is not executed on external targets. To exclude other targets,
 users may tag a target with `no-clang-tidy` or `noclangtidy`.
 
+### use with non-system gcc
+
+Create a label to the installation dir of your gcc toolchain, for example with
+skylib's `directory`.
+
+```py
+# BUILD file for gcc
+load("@bazel_skylib//rules/directory:directory.bzl", "directory")
+
+package(default_visibility = ["//visibility:public"])
+
+directory(
+    name = "toolchain_root",
+    srcs = glob([
+        "lib/**",
+        "x86_64-buildroot-linux-gnu/include/**",
+    ]),
+)
+
+directory(
+    name = "x86_64-buildroot-linux-gnu",
+    srcs = ["lib/gcc/x86_64-buildroot-linux-gnu/13.3.0"],
+)
+
+```
+
+then add the toolchain as an additional dependency and set the `clang_tidy_gcc_install_dir` option
+
+```text
+build:clang-tidy --@bazel_clang_tidy//:clang_tidy_gcc_install_dir=@gcc-linux-x86_64//:x86_64-buildroot-linux-gnu
+build:clang-tidy --@bazel_clang_tidy//:clang_tidy_additional_deps=@gcc-linux-x86_64//:toolchain_root
+```
+
+
 ## Features
 
 - Run clang-tidy on any C/C++ target

clang_tidy/clang_tidy.bzl

@@ -5,6 +5,7 @@ def _run_tidy(
         ctx,
         wrapper,
         exe,
+        gcc_install_dir,
         additional_deps,
         config,
         flags,
@@ -51,6 +52,12 @@ def _run_tidy(
     # start args passed to the compiler
     args.add("--")
 
+    if len(gcc_install_dir.files.to_list()) >= 2:
+        fail("clang_tidy_gcc_install_dir must contain at most one directory")
+
+    for dir in gcc_install_dir.files.to_list():
+        args.add("--gcc-install-dir=%s" % dir.path)
+
     ctx.actions.run(
         inputs = inputs,
         outputs = [outfile],
@@ -206,6 +213,7 @@ def _clang_tidy_aspect_impl(target, ctx):
 
     wrapper = ctx.attr._clang_tidy_wrapper.files_to_run
     exe = ctx.attr._clang_tidy_executable
+    gcc_install_dir = ctx.attr._clang_tidy_gcc_install_dir
     additional_deps = ctx.attr._clang_tidy_additional_deps
     config = ctx.attr._clang_tidy_config.files.to_list()[0]
 
@@ -230,6 +238,7 @@ def _clang_tidy_aspect_impl(target, ctx):
             ctx,
             wrapper,
             exe,
+            gcc_install_dir,
             additional_deps,
             config,
             c_flags if is_c_translation_unit(src, ctx.rule.attr.tags) else cxx_flags,
@@ -253,6 +262,7 @@ clang_tidy_aspect = aspect(
         "_cc_toolchain": attr.label(default = Label("@bazel_tools//tools/cpp:current_cc_toolchain")),
         "_clang_tidy_wrapper": attr.label(default = Label("//clang_tidy:clang_tidy")),
         "_clang_tidy_executable": attr.label(default = Label("//:clang_tidy_executable")),
+        "_clang_tidy_gcc_install_dir": attr.label(default = Label("//:clang_tidy_gcc_install_dir")),
         "_clang_tidy_additional_deps": attr.label(default = Label("//:clang_tidy_additional_deps")),
         "_clang_tidy_config": attr.label(default = Label("//:clang_tidy_config")),
     },