Expose the name of the checker producing each diagnostic message.
In clang-tidy we'd like to know the name of the checker producing each
diagnostic message. PathDiagnostic has BugType and Category fields, which are
both arbitrary human-readable strings, but we need to know the exact name of the
checker in the form that can be used in the CheckersControlList option to
enable/disable the specific checker.
This patch adds the CheckName field to the CheckerBase class, and sets it in
the CheckerManager::registerChecker() method, which gets them from the
Checkers that implement multiple checks have to store the names of each check
in the respective registerXXXChecker method.
Reviewers: jordan_rose, krememek
Reviewed By: jordan_rose
Differential Revision: http://llvm-reviews.chandlerc.com/D2557