Filter out '`' in mangled strings and reject them as invalid if found.

llvm-svn: 184656

libcxxabi/src/cxa_demangle.cpp

@@ -4382,7 +4382,7 @@ template <class C>
 void
 demangle(const char* first, const char* last, C& db, int& status)
 {
-    if (first >= last)
+    if (first >= last || std::find(first, last, '`') != last)
     {
         status = invalid_mangled_name;
         return;

libcxxabi/test/test_demangle.cpp

@@ -29593,6 +29593,7 @@ const char* invalid_cases[] =
     "Agentt",
     "NSoERj5E=Y1[uM:ga",
     "Aon_PmKVPDk7?fg4XP5smMUL6;<WsI_mgbf23cCgsHbT<l8EE\0uVRkNOoXDrgdA4[8IU>Vl<>IL8ayHpiVDDDXTY;^o9;i",
+    "_ZN8Blizza`d6Memory12voidp_returncvPT_IcEEv",
 };
 
 const unsigned NI = sizeof(invalid_cases) / sizeof(invalid_cases[0]);