[clang-tools-extra] 30d8aeb - [clang-tidy] Add option to disable bugprone-multi-level-pointer-conversion in C code (#141209)

[via cfe-commits]

Author: Carlos Galvez
Date: 2025-06-07T21:52:23+02:00
New Revision: 30d8aebbe2c3bd4bdda7a7feefeb7cf7d556a458

URL: https://github.com/llvm/llvm-project/commit/30d8aebbe2c3bd4bdda7a7feefeb7cf7d556a458
DIFF: https://github.com/llvm/llvm-project/commit/30d8aebbe2c3bd4bdda7a7feefeb7cf7d556a458.diff

LOG: [clang-tidy] Add option to disable bugprone-multi-level-pointer-conversion in C code (#141209)

Sometimes a project may want to enable this check only in C++, and
disable it in C, since the patterns the check warns about are quite
common and idiomatic in C, and there are no better alternatives.
    
Fixes #140659

Co-authored-by: Carlos Gálvez <carlos.galvez at zenseact.com>

Added: 
    clang-tools-extra/test/clang-tidy/checkers/bugprone/multi-level-implicit-pointer-conversion.c

Modified: 
    clang-tools-extra/clang-tidy/bugprone/MultiLevelImplicitPointerConversionCheck.cpp
    clang-tools-extra/clang-tidy/bugprone/MultiLevelImplicitPointerConversionCheck.h
    clang-tools-extra/docs/ReleaseNotes.rst
    clang-tools-extra/docs/clang-tidy/checks/bugprone/multi-level-implicit-pointer-conversion.rst

Removed: 
    


################################################################################
diff  --git a/clang-tools-extra/clang-tidy/bugprone/MultiLevelImplicitPointerConversionCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/MultiLevelImplicitPointerConversionCheck.cpp
index 7a989b07119aa..1a23473fdd229 100644
--- a/clang-tools-extra/clang-tidy/bugprone/MultiLevelImplicitPointerConversionCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/MultiLevelImplicitPointerConversionCheck.cpp
@@ -57,6 +57,17 @@ AST_MATCHER(QualType, isPointerType) {
 
 } // namespace
 
+MultiLevelImplicitPointerConversionCheck::
+    MultiLevelImplicitPointerConversionCheck(StringRef Name,
+                                             ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context), EnableInC(Options.get("EnableInC", true)) {
+}
+
+void MultiLevelImplicitPointerConversionCheck::storeOptions(
+    ClangTidyOptions::OptionMap &Opts) {
+  Options.store(Opts, "EnableInC", EnableInC);
+}
+
 void MultiLevelImplicitPointerConversionCheck::registerMatchers(
     MatchFinder *Finder) {
   Finder->addMatcher(

diff  --git a/clang-tools-extra/clang-tidy/bugprone/MultiLevelImplicitPointerConversionCheck.h b/clang-tools-extra/clang-tidy/bugprone/MultiLevelImplicitPointerConversionCheck.h
index 13228145ff35f..ef5f9f103c893 100644
--- a/clang-tools-extra/clang-tidy/bugprone/MultiLevelImplicitPointerConversionCheck.h
+++ b/clang-tools-extra/clang-tidy/bugprone/MultiLevelImplicitPointerConversionCheck.h
@@ -21,11 +21,17 @@ namespace clang::tidy::bugprone {
 class MultiLevelImplicitPointerConversionCheck : public ClangTidyCheck {
 public:
   MultiLevelImplicitPointerConversionCheck(StringRef Name,
-                                           ClangTidyContext *Context)
-      : ClangTidyCheck(Name, Context) {}
+                                           ClangTidyContext *Context);
+  void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
   std::optional<TraversalKind> getCheckTraversalKind() const override;
+  bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
+    return EnableInC ? true : LangOpts.CPlusPlus;
+  }
+
+private:
+  bool const EnableInC;
 };
 
 } // namespace clang::tidy::bugprone

diff  --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index a275d2ccfa004..10f6cf670ae16 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -159,6 +159,10 @@ Changes in existing checks
   false positives on deleted constructors that cannot be used to construct
   objects, even if they have public or protected access.
 
+- Added an option to :doc:`bugprone-multi-level-implicit-pointer-conversion
+  <clang-tidy/checks/bugprone/multi-level-implicit-pointer-conversion>` to
+  choose whether to enable the check in C code or not.
+
 - Improved :doc:`bugprone-optional-value-conversion
   <clang-tidy/checks/bugprone/optional-value-conversion>` check to detect
   conversion in argument of ``std::make_optional``.

diff  --git a/clang-tools-extra/docs/clang-tidy/checks/bugprone/multi-level-implicit-pointer-conversion.rst b/clang-tools-extra/docs/clang-tidy/checks/bugprone/multi-level-implicit-pointer-conversion.rst
index e6dc5c13aa025..14df6bd9ccea9 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/bugprone/multi-level-implicit-pointer-conversion.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/bugprone/multi-level-implicit-pointer-conversion.rst
@@ -42,3 +42,11 @@ Additionally, it is recommended that developers thoroughly check and verify the
 safety of the conversion before using an explicit cast. This extra level of
 caution can help catch potential issues early on in the development process,
 improving the overall reliability and maintainability of the code.
+
+Options
+-------
+
+.. option:: EnableInC
+
+   If `true`, enables the check in C code (it is always enabled in C++ code).
+   Default is `true`.

diff  --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/multi-level-implicit-pointer-conversion.c b/clang-tools-extra/test/clang-tidy/checkers/bugprone/multi-level-implicit-pointer-conversion.c
new file mode 100644
index 0000000000000..9dc5dae5c80f5
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/multi-level-implicit-pointer-conversion.c
@@ -0,0 +1,11 @@
+// RUN: %check_clang_tidy -check-suffixes=ENABLE-IN-C %s bugprone-multi-level-implicit-pointer-conversion %t -- -config="{CheckOptions: {bugprone-multi-level-implicit-pointer-conversion.EnableInC: true}}"
+// RUN: %check_clang_tidy -check-suffixes=DISABLE-IN-C %s bugprone-multi-level-implicit-pointer-conversion %t -- -config="{CheckOptions: {bugprone-multi-level-implicit-pointer-conversion.EnableInC: false}}"
+
+void free(void*);
+
+void test() {
+  char **p;
+  free(p);
+  // CHECK-MESSAGES-ENABLE-IN-C: :[[@LINE-1]]:8: warning: multilevel pointer conversion from 'char **' to 'void *', please use explicit cast [bugprone-multi-level-implicit-pointer-conversion]
+  free((void *)p);
+}