Expose the name of the checker producing each diagnostic message.

Summary:
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
CheckerRegistry.

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

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D2557

llvm-svn: 201186

clang/lib/StaticAnalyzer/Checkers/UndefinedArraySubscriptChecker.cpp

@@ -50,7 +50,7 @@ UndefinedArraySubscriptChecker::checkPreStmt(const ArraySubscriptExpr *A,
   if (!N)
     return;
   if (!BT)
-    BT.reset(new BuiltinBug("Array subscript is undefined"));
+    BT.reset(new BuiltinBug(this, "Array subscript is undefined"));
 
   // Generate a report for this bug.
   BugReport *R = new BugReport(*BT, BT->getName(), N);