fix a rewriter crash on zero length files.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@50126 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Rewrite/RewriteRope.cpp b/lib/Rewrite/RewriteRope.cpp
index db55aa1..7ee9fcc 100644
--- a/lib/Rewrite/RewriteRope.cpp
+++ b/lib/Rewrite/RewriteRope.cpp
@@ -741,6 +741,7 @@
/// allocation instead of doing tons of tiny allocations.
RopePiece RewriteRope::MakeRopeString(const char *Start, const char *End) {
unsigned Len = End-Start;
+ assert(Len && "Zero length RopePiece is invalid!");
// If we have space for this string in the current alloc buffer, use it.
if (AllocOffs+Len <= AllocChunkSize) {