[clang-tidy] add new checker for string literal with NUL character.

Summary:
This patch adds the support for detecting suspicious string
literals and their //incorrect// usage.

The following example shows a incorrect character escaping leading 
to an embedded NUL character. 
```
  std::string str = "\0x42";   // Should be "\x42".
```

The patch also add detection of truncated literal when a literal
is passed to a string constructor.

Reviewers: hokein, alexfh

Subscribers: LegalizeAdulthood, bcraig, Eugene.Zelenko, bkramer, cfe-commits

Differential Revision: http://reviews.llvm.org/D18783

llvm-svn: 265691

1 files changed, 35 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-tidy/misc/StringLiteralWithEmbeddedNulCheck.h b/clang-tools-extra/clang-tidy/misc/StringLiteralWithEmbeddedNulCheck.h
new file mode 100644
index 00000000000..e4a87fc280b
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/misc/StringLiteralWithEmbeddedNulCheck.h
@@ -0,0 +1,35 @@
+//===--- StringLiteralWithEmbeddedNulCheck.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_MISC_STRING_LITERAL_WITH_EMBEDDED_NUL_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_STRING_LITERAL_WITH_EMBEDDED_NUL_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace misc {
+
+/// Find suspicious string literals with embedded NUL characters.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/misc-string-literal-with-embedded-nul.html
+class StringLiteralWithEmbeddedNulCheck : public ClangTidyCheck {
+public:
+  StringLiteralWithEmbeddedNulCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace misc
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_STRING_LITERAL_WITH_EMBEDDED_NUL_H