diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp
index 120789b..b60271f 100644
--- a/lib/MC/ELFObjectWriter.cpp
+++ b/lib/MC/ELFObjectWriter.cpp
@@ -689,12 +689,15 @@
     const MCSymbol &Symbol = it->getSymbol();
 
     // Ignore non-linker visible symbols.
-    if (!Asm.isSymbolLinkerVisible(Symbol))
+    if (!Asm.isSymbolLinkerVisible(Symbol) && !Symbol.isUndefined())
       continue;
 
     if (!it->isExternal() && !Symbol.isUndefined())
       continue;
 
+    if (Symbol.isVariable())
+      continue;
+
     uint64_t &Entry = StringIndexMap[Symbol.getName()];
     if (!Entry) {
       Entry = StringTable.size();
diff --git a/test/MC/ELF/undef.s b/test/MC/ELF/undef.s
new file mode 100644
index 0000000..59bcc9f
--- /dev/null
+++ b/test/MC/ELF/undef.s
@@ -0,0 +1,15 @@
+// RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | elf-dump  | FileCheck %s
+
+// Test that there is an undefined reference to .Lset0, but not .Lset1
+
+        .long	.Lset0
+foo:
+bar:
+.Lset1 = foo - bar
+        .long	.Lset1
+
+// CHECK: ('_symbols', [
+// CHECK-NOT: Lset1
+// CHECK:  (('st_name', 9) # '.Lset0'
+// CHECK-NOT: Lset1
+// CHECK: (('sh_name', 36) # '.strtab'