Switch llvm to using comdats. For now always use groups with a single
section.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125526 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCSectionELF.cpp b/lib/MC/MCSectionELF.cpp
index 56138cb..d32aea1 100644
--- a/lib/MC/MCSectionELF.cpp
+++ b/lib/MC/MCSectionELF.cpp
@@ -61,6 +61,8 @@
     OS << 'a';
   if (Flags & ELF::SHF_EXECINSTR)
     OS << 'x';
+  if (Flags & ELF::SHF_GROUP)
+    OS << 'G';
   if (Flags & ELF::SHF_WRITE)
     OS << 'w';
   if (Flags & ELF::SHF_MERGE)
@@ -104,6 +106,8 @@
     OS << "," << EntrySize;
   }
 
+  if (Flags & ELF::SHF_GROUP)
+    OS << "," << Group->getName() << ",comdat";
   OS << '\n';
 }