1 files changed, 53 insertions, 0 deletions
diff --git a/clang-tools-extra/clang-tidy/google/GlobalNamesInHeadersCheck.cpp b/clang-tools-extra/clang-tidy/google/GlobalNamesInHeadersCheck.cpp
new file mode 100644
index 00000000000..d8303d51897
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/google/GlobalNamesInHeadersCheck.cpp
@@ -0,0 +1,53 @@
+//===--- GlobalNamesInHeadersCheck.cpp - clang-tidy -----------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "GlobalNamesInHeadersCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "clang/Lex/Lexer.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace readability {
+
+void
+GlobalNamesInHeadersCheck::registerMatchers(ast_matchers::MatchFinder *Finder) {
+  Finder->addMatcher(
+      decl(anyOf(usingDecl(), usingDirectiveDecl()),
+           hasDeclContext(translationUnitDecl())).bind("using_decl"),
+      this);
+}
+
+void GlobalNamesInHeadersCheck::check(const MatchFinder::MatchResult &Result) {
+  const auto *D = Result.Nodes.getNodeAs<Decl>("using_decl");
+  // If it comes from a macro, we'll assume it is fine.
+  if (D->getLocStart().isMacroID())
+    return;
+
+  // Ignore if it comes from the "main" file ...
+  if (Result.SourceManager->isInMainFile(
+          Result.SourceManager->getExpansionLoc(D->getLocStart()))) {
+    // unless that file is a header.
+    StringRef Filename = Result.SourceManager->getFilename(
+        Result.SourceManager->getSpellingLoc(D->getLocStart()));
+
+    if (!Filename.endswith(".h"))
+      return;
+  }
+
+  diag(D->getLocStart(),
+       "using declarations in the global namespace in headers are prohibited");
+}
+
+} // namespace readability
+} // namespace tidy
+} // namespace clang