From aa8cc0a53946665c37f4ad639ae380f72a483e8b Mon Sep 17 00:00:00 2001
From: Erik Eckstein <eeckstein@apple.com>
Date: Fri, 10 Mar 2017 15:36:26 -0800
Subject: [PATCH] demangler: fix a crash when trying to demangle a non-swift
 symbol

rdar://problem/30982254
---
 lib/Demangling/Demangler.cpp       | 2 ++
 test/Demangle/Inputs/manglings.txt | 1 +
 2 files changed, 3 insertions(+)

diff --git a/lib/Demangling/Demangler.cpp b/lib/Demangling/Demangler.cpp
index 26ce4fe309616..05db8b5aa0ef7 100644
--- a/lib/Demangling/Demangler.cpp
+++ b/lib/Demangling/Demangler.cpp
@@ -626,6 +626,8 @@ NodePointer Demangler::demangleIdentifier() {
 
 NodePointer Demangler::demangleOperatorIdentifier() {
   NodePointer Ident = popNode(Node::Kind::Identifier);
+  if (!Ident)
+    return nullptr;
 
   static const char op_char_table[] = "& @/= >    <*!|+?%-~   ^ .";
 
diff --git a/test/Demangle/Inputs/manglings.txt b/test/Demangle/Inputs/manglings.txt
index 3aa19f6b427e6..a7881ba7c593f 100644
--- a/test/Demangle/Inputs/manglings.txt
+++ b/test/Demangle/Inputs/manglings.txt
@@ -244,4 +244,5 @@ _T0s17MutableCollectionP1asAARzs012RandomAccessB0RzsAA11SubSequences013Bidirecti
 _T03foo4_123ABTf3psbpsb_n ---> function signature specialization <Arg[0] = [Constant Propagated String : u8'123'], Arg[1] = [Constant Propagated String : u8'123']> of foo
 _T04main5innerys5Int32Vz_yADctF25closure_with_box_argumentxz_Bi32__lXXTf1nc_n ---> function signature specialization <Arg[1] = [Closure Propagated : closure_with_box_argument, Argument Types : [<A> { var A } <Builtin.Int32>]> of main.inner (inout Swift.Int32, (Swift.Int32) -> ()) -> ()
 _T03foo6testityyyc_yyctF1a1bTf3pfpf_n ---> function signature specialization <Arg[0] = [Constant Propagated Function : a], Arg[1] = [Constant Propagated Function : b]> of foo.testit (() -> (), () -> ()) -> ()
+_SocketJoinOrLeaveMulticast ---> _SocketJoinOrLeaveMulticast