On an ELF system, ".debug_str" is mergeable and contains null terminated strings
composed of one byte characters.

llvm-svn: 143044
diff --git a/llvm/lib/MC/MCObjectFileInfo.cpp b/llvm/lib/MC/MCObjectFileInfo.cpp
index df8b99d..397e9c3 100644
--- a/llvm/lib/MC/MCObjectFileInfo.cpp
+++ b/llvm/lib/MC/MCObjectFileInfo.cpp
@@ -354,8 +354,9 @@
     Ctx->getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0,
                        SectionKind::getMetadata());
   DwarfStrSection =
-    Ctx->getELFSection(".debug_str", ELF::SHT_PROGBITS, 0,
-                       SectionKind::getMetadata());
+    Ctx->getELFSection(".debug_str", ELF::SHT_PROGBITS,
+                       ELF::SHF_MERGE | ELF::SHF_STRINGS,
+                       SectionKind::getMergeable1ByteCString());
   DwarfLocSection =
     Ctx->getELFSection(".debug_loc", ELF::SHT_PROGBITS, 0,
                        SectionKind::getMetadata());