diff --git a/llvm/lib/MC/WinCOFFObjectWriter.cpp b/llvm/lib/MC/WinCOFFObjectWriter.cpp
--- a/llvm/lib/MC/WinCOFFObjectWriter.cpp
+++ b/llvm/lib/MC/WinCOFFObjectWriter.cpp
@@ -353,9 +353,10 @@
     return nullptr;
 
   const MCSymbol &Aliasee = SymRef->getSymbol();
-  if (!Aliasee.isUndefined())
+  if (Aliasee.isUndefined() || Aliasee.isExternal())
+    return GetOrCreateCOFFSymbol(&Aliasee);
+  else
     return nullptr;
-  return GetOrCreateCOFFSymbol(&Aliasee);
 }
 
 /// This function takes a symbol data object from the assembler
diff --git a/llvm/test/MC/COFF/weak-alias-labels.s b/llvm/test/MC/COFF/weak-alias-labels.s
new file mode 100644
--- /dev/null
+++ b/llvm/test/MC/COFF/weak-alias-labels.s
@@ -0,0 +1,122 @@
+// RUN: llvm-mc -filetype=obj -triple i686-pc-win32 %s | llvm-readobj --symbols - | FileCheck %s
+// RUN: llvm-mc -filetype=obj -triple x86_64-pc-win32 %s | llvm-readobj --symbols - | FileCheck %s
+
+// When making weak references to labels/procedures, we reference them directly
+// if they have global symbols; otherwise, we need to create a global symbol for
+// the reference to resolve to.
+
+    .text
+
+    .globl proc1
+proc1:
+    ret
+
+proc2:
+    ret
+// CHECK:      Symbol {
+// CHECK:        Name: proc2
+// CHECK-NEXT:   Value: [[PROC2_VALUE:[0-9]+]]
+// CHECK-NEXT:   Section: [[PROC2_SECTION:.*]]
+// CHECK-NEXT:   BaseType: Null
+// CHECK-NEXT:   ComplexType: Null
+// CHECK-NEXT:   StorageClass: Static
+// CHECK-NEXT:   AuxSymbolCount: 0
+// CHECK-NEXT: }
+
+    .weak t1
+t1 = proc1
+
+// CHECK:      Symbol {
+// CHECK:        Name: t1
+// CHECK-NEXT:   Value: 0
+// CHECK-NEXT:   Section: IMAGE_SYM_UNDEFINED
+// CHECK-NEXT:   BaseType: Null
+// CHECK-NEXT:   ComplexType: Null
+// CHECK-NEXT:   StorageClass: WeakExternal
+// CHECK-NEXT:   AuxSymbolCount: 1
+// CHECK-NEXT:   AuxWeakExternal {
+// CHECK-NEXT:     Linked: proc1
+// CHECK-NEXT:     Search: Alias
+// CHECK-NEXT:   }
+// CHECK-NEXT: }
+
+    .weak t2
+t2 = proc2
+
+// CHECK:      Symbol {
+// CHECK:        Name: t2
+// CHECK-NEXT:   Value: 0
+// CHECK-NEXT:   Section: IMAGE_SYM_UNDEFINED
+// CHECK-NEXT:   BaseType: Null
+// CHECK-NEXT:   ComplexType: Null
+// CHECK-NEXT:   StorageClass: WeakExternal
+// CHECK-NEXT:   AuxSymbolCount: 1
+// CHECK-NEXT:   AuxWeakExternal {
+// CHECK-NEXT:     Linked: .weak.t2.default
+// CHECK-NEXT:     Search: Alias
+// CHECK-NEXT:   }
+// CHECK-NEXT: }
+// CHECK:      Symbol {
+// CHECK:        Name: .weak.t2.default
+// CHECK-NEXT:   Value: [[PROC2_VALUE]]
+// CHECK-NEXT:   Section: [[PROC2_SECTION]]
+// CHECK-NEXT:   BaseType: Null
+// CHECK-NEXT:   ComplexType: Null
+// CHECK-NEXT:   StorageClass: External
+// CHECK-NEXT:   AuxSymbolCount: 0
+// CHECK-NEXT: }
+
+    .weak t3
+t3 = foo
+
+// CHECK:      Symbol {
+// CHECK:        Name: t3
+// CHECK-NEXT:   Value: 0
+// CHECK-NEXT:   Section: IMAGE_SYM_UNDEFINED
+// CHECK-NEXT:   BaseType: Null
+// CHECK-NEXT:   ComplexType: Null
+// CHECK-NEXT:   StorageClass: WeakExternal
+// CHECK-NEXT:   AuxSymbolCount: 1
+// CHECK-NEXT:   AuxWeakExternal {
+// CHECK-NEXT:     Linked: foo
+// CHECK-NEXT:     Search: Alias
+// CHECK-NEXT:   }
+// CHECK-NEXT: }
+
+    .weak t4
+t4 = bar
+
+    .globl bar
+bar:
+    ret
+
+// CHECK:      Symbol {
+// CHECK:        Name: t4
+// CHECK-NEXT:   Value: 0
+// CHECK-NEXT:   Section: IMAGE_SYM_UNDEFINED
+// CHECK-NEXT:   BaseType: Null
+// CHECK-NEXT:   ComplexType: Null
+// CHECK-NEXT:   StorageClass: WeakExternal
+// CHECK-NEXT:   AuxSymbolCount: 1
+// CHECK-NEXT:   AuxWeakExternal {
+// CHECK-NEXT:     Linked: bar
+// CHECK-NEXT:     Search: Alias
+// CHECK-NEXT:   }
+// CHECK-NEXT: }
+
+    .weak t5
+t5 = t2
+
+// CHECK:      Symbol {
+// CHECK:        Name: t5
+// CHECK-NEXT:   Value: 0
+// CHECK-NEXT:   Section: IMAGE_SYM_UNDEFINED
+// CHECK-NEXT:   BaseType: Null
+// CHECK-NEXT:   ComplexType: Null
+// CHECK-NEXT:   StorageClass: WeakExternal
+// CHECK-NEXT:   AuxSymbolCount: 1
+// CHECK-NEXT:   AuxWeakExternal {
+// CHECK-NEXT:     Linked: t2
+// CHECK-NEXT:     Search: Alias
+// CHECK-NEXT:   }
+// CHECK-NEXT: }
diff --git a/llvm/test/MC/COFF/weak.s b/llvm/test/MC/COFF/weak.s
--- a/llvm/test/MC/COFF/weak.s
+++ b/llvm/test/MC/COFF/weak.s
@@ -32,6 +32,11 @@
     .weak   _test_weak_alias
     _test_weak_alias=_main
 
+    .weak weakfunc
+    .globl weakfunc
+weakfunc:
+    ret
+
 // CHECK: Symbols [
 
 // CHECK:      Symbol {
@@ -47,7 +52,7 @@
 // CHECK:      Symbol {
 // CHECK:        Name:           _test_weak
 // CHECK-NEXT:   Value:          0
-// CHECK-NEXT:   Section:        IMAGE_SYM_UNDEFINED (0)
+// CHECK-NEXT:   Section:        IMAGE_SYM_UNDEFINED
 // CHECK-NEXT:   BaseType:       Null
 // CHECK-NEXT:   ComplexType:    Null
 // CHECK-NEXT:   StorageClass:   WeakExternal
@@ -61,7 +66,7 @@
 // CHECK:      Symbol {
 // CHECK:        Name:                .weak._test_weak.default._main
 // CHECK-NEXT:   Value:               0
-// CHECK-NEXT:   Section:             IMAGE_SYM_ABSOLUTE (-1)
+// CHECK-NEXT:   Section:             IMAGE_SYM_ABSOLUTE
 // CHECK-NEXT:   BaseType:            Null
 // CHECK-NEXT:   ComplexType:         Null
 // CHECK-NEXT:   StorageClass:        External
@@ -71,23 +76,37 @@
 // CHECK:      Symbol {
 // CHECK:        Name:           _test_weak_alias
 // CHECK-NEXT:   Value:          0
-// CHECK-NEXT:   Section:        IMAGE_SYM_UNDEFINED (0)
+// CHECK-NEXT:   Section:        IMAGE_SYM_UNDEFINED
 // CHECK-NEXT:   BaseType:       Null
 // CHECK-NEXT:   ComplexType:    Null
 // CHECK-NEXT:   StorageClass:   WeakExternal
 // CHECK-NEXT:   AuxSymbolCount: 1
 // CHECK-NEXT:   AuxWeakExternal {
-// CHECK-NEXT:     Linked: .weak._test_weak_alias.default
-// CHECK-NEXT:      Search: Alias
+// CHECK-NEXT:     Linked: _main
+// CHECK-NEXT:     Search: Alias
 // CHECK-NEXT:   }
 // CHECK-NEXT: }
 
 // CHECK:      Symbol {
-// CHECK:        Name: .weak._test_weak_alias.default._main
-// CHECK-NEXT:   Value: 0
-// CHECK-NEXT:   Section: .text
-// CHECK-NEXT:   BaseType: Null
-// CHECK-NEXT:   ComplexType: Null
-// CHECK-NEXT:   StorageClass: External
+// CHECK:        Name:           weakfunc
+// CHECK-NEXT:   Value:          0
+// CHECK-NEXT:   Section:        IMAGE_SYM_UNDEFINED
+// CHECK-NEXT:   BaseType:       Null
+// CHECK-NEXT:   ComplexType:    Null
+// CHECK-NEXT:   StorageClass:   WeakExternal
+// CHECK-NEXT:   AuxSymbolCount: 1
+// CHECK-NEXT:   AuxWeakExternal {
+// CHECK-NEXT:     Linked: .weak.weakfunc.default
+// CHECK-NEXT:     Search: Alias
+// CHECK-NEXT:   }
+// CHECK-NEXT: }
+// CHECK:      Symbol {
+// CHECK:        Name:           .weak.weakfunc.default
+// CHECK-NOT:    Value:          0
+// CHECK-NOT:  Symbol {
+// CHECK:        Section:        .text
+// CHECK-NEXT:   BaseType:       Null
+// CHECK-NEXT:   ComplexType:    Null
+// CHECK-NEXT:   StorageClass:   External
 // CHECK-NEXT:   AuxSymbolCount: 0
 // CHECK-NEXT: }