[clang-tools-extra] [clang-tidy] Added check 'misc-visibility-change-to-virtual-function' (PR #140086)

[Balázs Kéri via cfe-commits]

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@@ -0,0 +1,147 @@
+//===--- VisibilityChangeToVirtualFunctionCheck.cpp - clang-tidy ----------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "VisibilityChangeToVirtualFunctionCheck.h"
+#include "../utils/Matchers.h"
+#include "../utils/OptionsUtils.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+using namespace clang;
+
+namespace {
+AST_MATCHER(NamedDecl, isOperatorDecl) {
+  DeclarationName::NameKind NK = Node.getDeclName().getNameKind();
+  return NK != DeclarationName::Identifier &&
+         NK != DeclarationName::CXXConstructorName &&
+         NK != DeclarationName::CXXDestructorName;
+}
+} // namespace
+
+namespace clang::tidy {
+
+template <>
+struct OptionEnumMapping<
+    misc::VisibilityChangeToVirtualFunctionCheck::ChangeKind> {
+  static llvm::ArrayRef<std::pair<
+      misc::VisibilityChangeToVirtualFunctionCheck::ChangeKind, StringRef>>
+  getEnumMapping() {
+    static constexpr std::pair<
+        misc::VisibilityChangeToVirtualFunctionCheck::ChangeKind, StringRef>
+        Mapping[] = {
+            {misc::VisibilityChangeToVirtualFunctionCheck::ChangeKind::Any,
+             "any"},
+            {misc::VisibilityChangeToVirtualFunctionCheck::ChangeKind::Widening,
+             "widening"},
+            {misc::VisibilityChangeToVirtualFunctionCheck::ChangeKind::
+                 Narrowing,
+             "narrowing"},
+        };
+    return {Mapping};
+  }
+};
+
+namespace misc {
+
+VisibilityChangeToVirtualFunctionCheck::VisibilityChangeToVirtualFunctionCheck(
+    StringRef Name, ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context),
+      DetectVisibilityChange(
+          Options.get("DisallowedVisibilityChange", ChangeKind::Any)),
+      CheckDestructors(Options.get("CheckDestructors", false)),
+      CheckOperators(Options.get("CheckOperators", false)),
+      IgnoredFunctions(utils::options::parseStringList(
+          Options.get("IgnoredFunctions", ""))) {}
+
+void VisibilityChangeToVirtualFunctionCheck::storeOptions(
+    ClangTidyOptions::OptionMap &Opts) {
+  Options.store(Opts, "DisallowedVisibilityChange", DetectVisibilityChange);
+  Options.store(Opts, "CheckDestructors", CheckDestructors);
+  Options.store(Opts, "CheckOperators", CheckOperators);
+  Options.store(Opts, "IgnoredFunctions",
+                utils::options::serializeStringList(IgnoredFunctions));
+}
+
+void VisibilityChangeToVirtualFunctionCheck::registerMatchers(
+    MatchFinder *Finder) {
+  auto IgnoredDecl =
+      namedDecl(matchers::matchesAnyListedName(IgnoredFunctions));
+  auto FilterDestructors =
+      CheckDestructors ? decl() : decl(unless(cxxDestructorDecl()));
+  auto FilterOperators =
+      CheckOperators ? namedDecl() : namedDecl(unless(isOperatorDecl()));
+  Finder->addMatcher(
+      cxxMethodDecl(
+          isVirtual(), FilterDestructors, FilterOperators,
+          ofClass(
+              cxxRecordDecl(unless(isExpansionInSystemHeader())).bind("class")),
+          forEachOverridden(cxxMethodDecl(ofClass(cxxRecordDecl().bind("base")),
+                                          unless(IgnoredDecl))
+                                .bind("base_func")))
+          .bind("func"),
+      this);
+}
+
+void VisibilityChangeToVirtualFunctionCheck::check(
+    const MatchFinder::MatchResult &Result) {
+  const auto *MatchedFunction = Result.Nodes.getNodeAs<FunctionDecl>("func");
+  if (!MatchedFunction->isCanonicalDecl())
+    return;
+
+  const auto *ParentClass = Result.Nodes.getNodeAs<CXXRecordDecl>("class");
+  const auto *OverriddenFunction =
+      Result.Nodes.getNodeAs<FunctionDecl>("base_func");
+  const auto *BaseClass = Result.Nodes.getNodeAs<CXXRecordDecl>("base");
+
+  AccessSpecifier ActualAccess = MatchedFunction->getAccess();
----------------
balazske wrote:

In this single case I do not like to add `const`, or variables `ParentClass`, `BaseClass`, `MatchedFunction`, `OverriddenFunction` should be made `const` too.

https://github.com/llvm/llvm-project/pull/140086