Index: lld/MachO/InputSection.cpp
===================================================================
--- lld/MachO/InputSection.cpp
+++ lld/MachO/InputSection.cpp
@@ -67,7 +67,7 @@
   // First, try to find a symbol that's near the offset. Use it as a reference
   // point.
   if (auto *sym = getContainingSymbol(off))
-    return (toString(getFile()) + ":(symbol " + sym->getName() + "+0x" +
+    return (toString(getFile()) + ":(symbol " + toString(*sym) + "+0x" +
             Twine::utohexstr(off - sym->value) + ")")
         .str();
 
Index: lld/test/MachO/invalid/undefined-symbol.s
===================================================================
--- lld/test/MachO/invalid/undefined-symbol.s
+++ lld/test/MachO/invalid/undefined-symbol.s
@@ -4,18 +4,24 @@
 # RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/foo.s -o %t/foo.o
 # RUN: llvm-ar crs %t/foo.a %t/foo.o
 # RUN: not %lld --icf=all -o /dev/null %t/main.o 2>&1 | \
-# RUN:     FileCheck %s -DSYM=_foo -DLOC='%t/main.o:(symbol _main+0x1)'
+# RUN:     FileCheck %s -DSYM=__ZN3foo3barEi -DLOC='%t/main.o:(symbol _main+0x1)'
+# RUN: not %lld -demangle --icf=all -o /dev/null %t/main.o 2>&1 | \
+# RUN:     FileCheck %s -DSYM='foo::bar(int)' -DLOC='%t/main.o:(symbol _main+0x1)'
 # RUN: not %lld -o /dev/null %t/main.o %t/foo.a 2>&1 | \
-# RUN:     FileCheck %s -DSYM=_bar -DLOC='%t/foo.a(foo.o):(symbol _foo+0x1)'
+# RUN:     FileCheck %s -DSYM=_bar -DLOC='%t/foo.a(foo.o):(symbol __ZN3foo3barEi+0x1)'
+# RUN: not %lld -demangle -o /dev/null %t/main.o %t/foo.a 2>&1 | \
+# RUN:     FileCheck %s -DSYM=_bar -DLOC='%t/foo.a(foo.o):(symbol foo::bar(int)+0x1)'
 # RUN: not %lld -o /dev/null %t/main.o -force_load %t/foo.a 2>&1 | \
-# RUN:     FileCheck %s -DSYM=_bar -DLOC='%t/foo.a(foo.o):(symbol _foo+0x1)'
+# RUN:     FileCheck %s -DSYM=_bar -DLOC='%t/foo.a(foo.o):(symbol __ZN3foo3barEi+0x1)'
+# RUN: not %lld -demangle -o /dev/null %t/main.o -force_load %t/foo.a 2>&1 | \
+# RUN:     FileCheck %s -DSYM=_bar -DLOC='%t/foo.a(foo.o):(symbol foo::bar(int)+0x1)'
 # CHECK: error: undefined symbol: [[SYM]]
 # CHECK-NEXT: >>> referenced by [[LOC]]
 
 #--- foo.s
-.globl _foo
+.globl __ZN3foo3barEi
 .text
-_foo:
+__ZN3foo3barEi:
   callq _bar
   retq
 
@@ -23,13 +29,13 @@
 .text
 
 _anotherref:
-  callq _foo
+  callq __ZN3foo3barEi
   movq $0, %rax
   retq
 
 .globl _main
 _main:
-  callq _foo
+  callq __ZN3foo3barEi
   movq $0, %rax
   retq