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/CastToStructChecker.cpp b/lib/Analysis/CastToStructChecker.cpp
index bda8ff4..ccd4a33 100644
--- a/lib/Analysis/CastToStructChecker.cpp
+++ b/lib/Analysis/CastToStructChecker.cpp
@@ -65,8 +65,7 @@
                             "Casting a non-structure type to a structure type "
                             "and accessing a field can lead to memory access "
                             "errors or data corruption.");
-      RangedBugReport *R = new RangedBugReport(*BT,BT->getDescription().c_str(),
-                                               N);
+      RangedBugReport *R = new RangedBugReport(*BT,BT->getDescription(), N);
       R->addRange(CE->getSourceRange());
       C.EmitReport(R);
     }