Change *BugReport constructors to take StringRefs.

- Eliminates many calls to std::string.c_str()
- Fixes an invalid read in ReturnStackAddressChecker due to an unsafe call to
  StringRef.data() which doesn't guarantee null-termination.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@88779 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/BadCallChecker.cpp b/lib/Analysis/BadCallChecker.cpp
index 4175e8d..7a7ea18 100644
--- a/lib/Analysis/BadCallChecker.cpp
+++ b/lib/Analysis/BadCallChecker.cpp
@@ -46,7 +46,7 @@
                 "Called function pointer is a null or undefined pointer value");
 
       EnhancedBugReport *R =
-        new EnhancedBugReport(*BT, BT->getDescription().c_str(), N);
+        new EnhancedBugReport(*BT, BT->getDescription(), N);
         
       R->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue,
                            bugreporter::GetCalleeExpr(N));