1 files changed, 3 insertions, 1 deletions
diff --git a/clang/lib/Basic/SourceManager.cpp b/clang/lib/Basic/SourceManager.cpp
index c0b045331dd..6c2bd7d2332 100644
--- a/clang/lib/Basic/SourceManager.cpp
+++ b/clang/lib/Basic/SourceManager.cpp
@@ -484,10 +484,12 @@ std::pair<int, unsigned>
 SourceManager::AllocateLoadedSLocEntries(unsigned NumSLocEntries,
                                          unsigned TotalSize) {
   assert(ExternalSLocEntries && "Don't have an external sloc source");
+  // Make sure we're not about to run out of source locations.
+  if (CurrentLoadedOffset - TotalSize < NextLocalOffset)
+    return std::make_pair(0, 0);
   LoadedSLocEntryTable.resize(LoadedSLocEntryTable.size() + NumSLocEntries);
   SLocEntryLoaded.resize(LoadedSLocEntryTable.size());
   CurrentLoadedOffset -= TotalSize;
-  assert(CurrentLoadedOffset >= NextLocalOffset && "Out of source locations");
   int ID = LoadedSLocEntryTable.size();
   return std::make_pair(-ID - 1, CurrentLoadedOffset);
 }