[DEBUGINFO] Do not output labels for empty macinfo sections.

Summary:
If there is no debug info for macros, do not emit labels for empty
macinfo sections.

Reviewers: probinson, echristo

Subscribers: aprantl, llvm-commits, JDevlieghere

Differential Revision: https://reviews.llvm.org/D43589

llvm-svn: 325803

1 files changed, 5 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index dfb36fa1d43..99ed096d132 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -2020,8 +2020,11 @@ void DwarfDebug::emitDebugMacinfo() {
     auto *SkCU = TheCU.getSkeleton();
     DwarfCompileUnit &U = SkCU ? *SkCU : TheCU;
     auto *CUNode = cast<DICompileUnit>(P.first);
-    Asm->OutStreamer->EmitLabel(U.getMacroLabelBegin());
-    handleMacroNodes(CUNode->getMacros(), U);
+    DIMacroNodeArray Macros = CUNode->getMacros();
+    if (!Macros.empty()) {
+      Asm->OutStreamer->EmitLabel(U.getMacroLabelBegin());
+      handleMacroNodes(Macros, U);
+    }
   }
   Asm->OutStreamer->AddComment("End Of Macro List Mark");
   Asm->EmitInt8(0);