Index: llvm/trunk/lib/Object/IRObjectFile.cpp
===================================================================
--- llvm/trunk/lib/Object/IRObjectFile.cpp
+++ llvm/trunk/lib/Object/IRObjectFile.cpp
@@ -113,10 +113,13 @@
       Res |= BasicSymbolRef::SF_Undefined;
       Res |= BasicSymbolRef::SF_Global;
       break;
-    case RecordStreamer::GlobalWeak:
+    case RecordStreamer::DefinedWeak:
       Res |= BasicSymbolRef::SF_Weak;
       Res |= BasicSymbolRef::SF_Global;
       break;
+    case RecordStreamer::UndefinedWeak:
+      Res |= BasicSymbolRef::SF_Weak;
+      Res |= BasicSymbolRef::SF_Undefined;
     }
     AsmUndefinedRefs(Key, BasicSymbolRef::Flags(Res));
   }
Index: llvm/trunk/lib/Object/RecordStreamer.h
===================================================================
--- llvm/trunk/lib/Object/RecordStreamer.h
+++ llvm/trunk/lib/Object/RecordStreamer.h
@@ -15,7 +15,8 @@
 namespace llvm {
 class RecordStreamer : public MCStreamer {
 public:
-  enum State { NeverSeen, Global, GlobalWeak, Defined, DefinedGlobal, Used };
+  enum State { NeverSeen, Global, Defined, DefinedGlobal, DefinedWeak, Used,
+               UndefinedWeak};
 
 private:
   StringMap<State> Symbols;
Index: llvm/trunk/lib/Object/RecordStreamer.cpp
===================================================================
--- llvm/trunk/lib/Object/RecordStreamer.cpp
+++ llvm/trunk/lib/Object/RecordStreamer.cpp
@@ -23,8 +23,10 @@
   case Used:
     S = Defined;
     break;
-  case GlobalWeak:
+  case DefinedWeak:
     break;
+  case UndefinedWeak:
+    S = DefinedWeak;
   }
 }
 
@@ -34,15 +36,16 @@
   switch (S) {
   case DefinedGlobal:
   case Defined:
-    S = (Attribute == MCSA_Weak) ? GlobalWeak : DefinedGlobal;
+    S = (Attribute == MCSA_Weak) ? DefinedWeak : DefinedGlobal;
     break;
 
   case NeverSeen:
   case Global:
   case Used:
-    S = (Attribute == MCSA_Weak) ? GlobalWeak : Global;
+    S = (Attribute == MCSA_Weak) ? UndefinedWeak : Global;
     break;
-  case GlobalWeak:
+  case UndefinedWeak:
+  case DefinedWeak:
     break;
   }
 }
@@ -53,7 +56,8 @@
   case DefinedGlobal:
   case Defined:
   case Global:
-  case GlobalWeak:
+  case DefinedWeak:
+  case UndefinedWeak:
     break;
 
   case NeverSeen:
Index: llvm/trunk/test/Object/X86/nm-bitcodeweak.test
===================================================================
--- llvm/trunk/test/Object/X86/nm-bitcodeweak.test
+++ llvm/trunk/test/Object/X86/nm-bitcodeweak.test
@@ -1,6 +1,7 @@
 ; RUN: llvm-as %s -o=%t1
 ; RUN: llvm-nm %t1 | FileCheck %s
 
+; Check that __libc_blah is reported as defined weak.
 ; CHECK: W __libc_blah
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
@@ -8,3 +9,5 @@
 
 module asm ".weak __libc_blah"
 module asm ".equ __libc_blah, blah"
+module asm ".globl blah"
+module asm "blah: ret"
Index: llvm/trunk/test/Object/X86/nm-undefinedweak.test
===================================================================
--- llvm/trunk/test/Object/X86/nm-undefinedweak.test
+++ llvm/trunk/test/Object/X86/nm-undefinedweak.test
@@ -0,0 +1,10 @@
+; RUN: llvm-as %s -o=%t1
+; RUN: llvm-nm %t1 | FileCheck %s
+
+; Check that patatino is reported as undefined weak.
+; CHECK: w patatino
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-freebsd11.0"
+
+module asm ".weak patatino"