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/ArrayBoundChecker.cpp b/lib/Analysis/ArrayBoundChecker.cpp
index 34a5631..549a22b 100644
--- a/lib/Analysis/ArrayBoundChecker.cpp
+++ b/lib/Analysis/ArrayBoundChecker.cpp
@@ -77,7 +77,7 @@
 
     // Generate a report for this bug.
     RangedBugReport *report = 
-      new RangedBugReport(*BT, BT->getDescription().c_str(), N);
+      new RangedBugReport(*BT, BT->getDescription(), N);
 
     report->addRange(S->getSourceRange());