[clang-tidy] Add a generic header guard checker + LLVM implementation.

The implementation is split into a generic part and a LLVM-specific part.
Other codebases can implement it with their own style. The specific features
supported are:

- Verification (and fixing) of header guards against a style based on the file path
- Automatic insertion of header guards for headers that are missing them
- A warning when the header guard doesn't enable our fancy header guard optimization
(e.g. when there's an include preceeding the guard)
- Automatic insertion of a comment with the guard name after #endif.

For the LLVM style we disable #endif comments for now, they're not very common
in the codebase. We also only flag headers in the include directories, there
doesn't seem to be a common style outside.

Differential Revision: http://reviews.llvm.org/D4867

llvm-svn: 215548

1 files changed, 29 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-tidy/llvm/HeaderGuardCheck.h b/clang-tools-extra/clang-tidy/llvm/HeaderGuardCheck.h
new file mode 100644
index 00000000000..fa99f9967f0
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/llvm/HeaderGuardCheck.h
@@ -0,0 +1,29 @@
+//===--- HeaderGuardCheck.h - clang-tidy ------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_LLVM_HEADER_GUARD_CHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_LLVM_HEADER_GUARD_CHECK_H
+
+#include "../utils/HeaderGuard.h"
+
+namespace clang {
+namespace tidy {
+
+/// Finds and fixes header guards that do not adhere to LLVM style.
+class LLVMHeaderGuardCheck : public HeaderGuardCheck {
+public:
+  bool shouldSuggestEndifComment(StringRef Filename) override { return false; }
+  bool shouldFixHeaderGuard(StringRef Filename) override;
+  std::string getHeaderGuard(StringRef Filename, StringRef OldGuard) override;
+};
+
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_LLVM_HEADER_GUARD_CHECK_H