[clang-tidy] Add a checker that warns on const string & members.

Summary:
Those are considered unsafe and should be replaced with simple pointers or
full copies. It recognizes both std::string and ::string.

Reviewers: alexfh, djasper

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D4522

llvm-svn: 213133

1 files changed, 50 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-tidy/google/StringReferenceMemberCheck.h b/clang-tools-extra/clang-tidy/google/StringReferenceMemberCheck.h
new file mode 100644
index 00000000000..4b4bff62d8c
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/google/StringReferenceMemberCheck.h
@@ -0,0 +1,50 @@
+//===--- StringReferenceMemberCheck.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_GOOGLE_STRING_REF_MEMBER_CHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_STRING_REF_MEMBER_CHECK_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace runtime {
+
+/// \brief Finds members of type 'const string&'.
+///
+/// const string reference members are generally considered unsafe as they can
+/// be created from a temporary quite easily.
+///
+/// \code
+/// struct S {
+///  S(const string &Str) : Str(Str) {}
+///  const string &Str;
+/// };
+/// S instance("string");
+/// \endcode
+///
+/// In the constructor call a string temporary is created from const char * and
+/// destroyed immediately after the call. This leaves around a dangling
+/// reference.
+///
+/// This check emit warnings for both std::string and ::string const reference
+/// members.
+///
+/// Corresponding cpplint.py check name: 'runtime/member_string_reference'.
+class StringReferenceMemberCheck : public ClangTidyCheck {
+public:
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace runtime
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_STRING_REF_MEMBER_CHECK_H