[SemaExprCXX] Avoid calling isInSystemHeader for invalid source locat…

…ions

Summary:
While diagnosing a CXXNewExpr warning, we were calling isInSystemHeader(), which expect to be
called with a valid source location. This causes an assertion failure if the location is unknown.
A quick grep shows it's not without precedent to guard calls to the function with a
"Loc.isValid()".

This fixes a test failure in LLDB, which always creates object with invalid source locations as it
does not (always) have access to the source.

Reviewers: nlewycky

Subscribers: lldb-commits, cfe-commits

Differential Revision: http://reviews.llvm.org/D17847

llvm-svn: 262700

clang/lib/Sema/SemaExprCXX.cpp

@@ -1551,7 +1551,8 @@ Sema::BuildCXXNew(SourceRange Range, bool UseGlobal,
   // new.
   if (PlacementArgs.empty() && OperatorNew &&
       (OperatorNew->isImplicit() ||
-       getSourceManager().isInSystemHeader(OperatorNew->getLocStart()))) {
+       (OperatorNew->getLocStart().isValid() &&
+        getSourceManager().isInSystemHeader(OperatorNew->getLocStart())))) {
     if (unsigned Align = Context.getPreferredTypeAlign(AllocType.getTypePtr())){
       unsigned SuitableAlign = Context.getTargetInfo().getSuitableAlign();
       if (Align > SuitableAlign)