if some functions don't have debug info, we were outputing the same label at the start of each of those functions. This makes assemblers unhappy

llvm-svn: 49176

1 files changed, 5 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/DwarfWriter.cpp b/llvm/lib/CodeGen/DwarfWriter.cpp
index 010dfa0a793..947b420cd51 100644
--- a/llvm/lib/CodeGen/DwarfWriter.cpp
+++ b/llvm/lib/CodeGen/DwarfWriter.cpp
@@ -2720,8 +2720,11 @@ public:
 
     // Emit label for the implicitly defined dbg.stoppoint at the start of
     // the function.
-    const SourceLineInfo &LineInfo = MMI->getSourceLines()[0];
-    Asm->printLabel(LineInfo.getLabelID());
+    const std::vector<SourceLineInfo> &LineInfos = MMI->getSourceLines();
+    if (!LineInfos.empty()) {
+      const SourceLineInfo &LineInfo = LineInfos[0];
+      Asm->printLabel(LineInfo.getLabelID());
+    }
   }
   
   /// EndFunction - Gather and emit post-function debug information.