--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang-tools-extra/clang-tidy/llvmlibc/RestrictSystemLibcHeadersCheck.cpp	Mon May 25 11:55:54 2020 +0900
@@ -0,0 +1,67 @@
+//===--- RestrictSystemLibcHeadersCheck.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 "RestrictSystemLibcHeadersCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/HeaderSearch.h"
+#include "clang/Lex/HeaderSearchOptions.h"
+
+namespace clang {
+namespace tidy {
+namespace llvm_libc {
+
+namespace {
+
+class RestrictedIncludesPPCallbacks
+    : public portability::RestrictedIncludesPPCallbacks {
+public:
+  explicit RestrictedIncludesPPCallbacks(
+      RestrictSystemLibcHeadersCheck &Check, const SourceManager &SM,
+      const SmallString<128> CompilerIncudeDir)
+      : portability::RestrictedIncludesPPCallbacks(Check, SM),
+        CompilerIncudeDir(CompilerIncudeDir) {}
+
+  void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
+                          StringRef FileName, bool IsAngled,
+                          CharSourceRange FilenameRange, const FileEntry *File,
+                          StringRef SearchPath, StringRef RelativePath,
+                          const Module *Imported,
+                          SrcMgr::CharacteristicKind FileType) override;
+
+private:
+  const SmallString<128> CompilerIncudeDir;
+};
+
+} // namespace
+
+void RestrictedIncludesPPCallbacks::InclusionDirective(
+    SourceLocation HashLoc, const Token &IncludeTok, StringRef FileName,
+    bool IsAngled, CharSourceRange FilenameRange, const FileEntry *File,
+    StringRef SearchPath, StringRef RelativePath, const Module *Imported,
+    SrcMgr::CharacteristicKind FileType) {
+  // Compiler provided headers are allowed (e.g stddef.h).
+  if (SrcMgr::isSystem(FileType) && SearchPath == CompilerIncudeDir)
+    return;
+  portability::RestrictedIncludesPPCallbacks::InclusionDirective(
+      HashLoc, IncludeTok, FileName, IsAngled, FilenameRange, File, SearchPath,
+      RelativePath, Imported, FileType);
+}
+
+void RestrictSystemLibcHeadersCheck::registerPPCallbacks(
+    const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
+  SmallString<128> CompilerIncudeDir =
+      StringRef(PP->getHeaderSearchInfo().getHeaderSearchOpts().ResourceDir);
+  llvm::sys::path::append(CompilerIncudeDir, "include");
+  PP->addPPCallbacks(std::make_unique<RestrictedIncludesPPCallbacks>(
+      *this, SM, CompilerIncudeDir));
+}
+
+} // namespace llvm_libc
+} // namespace tidy
+} // namespace clang