Index: lld/trunk/ELF/Symbols.cpp
===================================================================
--- lld/trunk/ELF/Symbols.cpp
+++ lld/trunk/ELF/Symbols.cpp
@@ -275,13 +275,13 @@
     return false;
   if (computeBinding() == STB_LOCAL)
     return false;
+
   // If a PIE binary was not linked against any shared libraries, then we can
   // safely drop weak undef symbols from .dynsym.
   if (isUndefWeak() && Config->Pie && SharedFiles.empty())
     return false;
-  if (!isDefined())
-    return true;
-  return ExportDynamic;
+
+  return isUndefined() || isShared() || ExportDynamic;
 }
 
 // Print out a log message for --trace-symbol.
Index: lld/trunk/test/ELF/lto/common4.ll
===================================================================
--- lld/trunk/test/ELF/lto/common4.ll
+++ lld/trunk/test/ELF/lto/common4.ll
@@ -0,0 +1,21 @@
+; REQUIRES: x86
+
+;; Make sure that common symbols are properly internalized.
+;; In this file, @a does not interpose any symbol in a DSO,
+;; so LTO should be able to internelize it.
+
+; RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux /dev/null -o %t.so.o
+; RUN: ld.lld -shared -o %t.so %t.so.o
+
+; RUN: llvm-as %s -o %t.o
+; RUN: ld.lld -o %t.exe -save-temps %t.o %t.so
+; RUN: llvm-dis < %t.exe.0.2.internalize.bc | FileCheck %s
+
+; RUN: ld.lld -pie -o %t.exe -save-temps %t.o
+; RUN: llvm-dis < %t.exe.0.2.internalize.bc | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@a = common dso_local local_unnamed_addr global i32 0, align 4
+; CHECK-DAG: @a = internal global i32 0, align 4