[clang-tidy] Add misc-use-anonymous-namespace check

Differential Revision: https://reviews.llvm.org/D137340

1 files changed, 72 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-tidy/misc/UseAnonymousNamespaceCheck.cpp b/clang-tools-extra/clang-tidy/misc/UseAnonymousNamespaceCheck.cpp
new file mode 100644
index 0000000..5632347
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/misc/UseAnonymousNamespaceCheck.cpp
@@ -0,0 +1,72 @@
+//===--- UseAnonymousNamespaceCheck.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 "UseAnonymousNamespaceCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace misc {
+namespace {
+AST_POLYMORPHIC_MATCHER(isStatic, AST_POLYMORPHIC_SUPPORTED_TYPES(FunctionDecl,
+                                                                  VarDecl)) {
+  return Node.getStorageClass() == SC_Static;
+}
+
+AST_MATCHER(FunctionDecl, isMemberFunction) {
+  return llvm::isa<CXXMethodDecl>(&Node);
+}
+AST_MATCHER(VarDecl, isStaticDataMember) { return Node.isStaticDataMember(); }
+} // namespace
+
+static bool isInAnonymousNamespace(const Decl *Decl) {
+  const DeclContext *DC = Decl->getDeclContext();
+  if (DC && DC->isNamespace()) {
+    const auto *ND = llvm::cast<NamespaceDecl>(DC);
+    if (ND && ND->isAnonymousNamespace())
+      return true;
+  }
+  return false;
+}
+
+template <typename T>
+void UseAnonymousNamespaceCheck::processMatch(const T *MatchedDecl) {
+  StringRef Type = llvm::isa<VarDecl>(MatchedDecl) ? "variable" : "function";
+  if (isInAnonymousNamespace(MatchedDecl))
+    diag(MatchedDecl->getLocation(), "%0 %1 declared 'static' in "
+                                     "anonymous namespace, remove 'static'")
+        << Type << MatchedDecl;
+  else
+    diag(MatchedDecl->getLocation(),
+         "%0 %1 declared 'static', move to anonymous namespace instead")
+        << Type << MatchedDecl;
+}
+
+void UseAnonymousNamespaceCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(
+      functionDecl(isStatic(), unless(isMemberFunction())).bind("func"), this);
+  Finder->addMatcher(
+      varDecl(isStatic(), unless(anyOf(isStaticLocal(), isStaticDataMember())))
+          .bind("var"),
+      this);
+}
+
+void UseAnonymousNamespaceCheck::check(const MatchFinder::MatchResult &Result) {
+  if (const auto *MatchedDecl = Result.Nodes.getNodeAs<FunctionDecl>("func"))
+    processMatch(MatchedDecl);
+
+  if (const auto *MatchedDecl = Result.Nodes.getNodeAs<VarDecl>("var"))
+    processMatch(MatchedDecl);
+}
+
+} // namespace misc
+} // namespace tidy
+} // namespace clang