Best effort for C stack traces with unrecognised symbol format

src/checks.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 41 matching lines @@
     for (int i = 1; i < size; ++i) {
       i::OS::PrintError("%2d: ", i);
       char mangled[201];
       if (sscanf(symbols[i], "%*[^(]%*[(]%200[^)+]", mangled) == 1) {  // NOLINT
         int status;
         size_t length;
         char* demangled = abi::__cxa_demangle(mangled, NULL, &length, &status);
         i::OS::PrintError("%s\n", demangled != NULL ? demangled : mangled);
         free(demangled);
       } else {
-        i::OS::PrintError("??\n");
+        i::OS::PrintError("%s\n", symbols[i]);
       }
     }
   }
   free(symbols);
 #endif  // V8_LIBC_GLIBC || V8_OS_BSD
 }
 
 
 // Contains protection against recursive calls (faults while handling faults).
 extern "C" void V8_Fatal(const char* file, int line, const char* format, ...) {
@@ skipping 52 matching lines @@
   i::OS::PrintError("\n#\n\n");
   i::OS::Abort();
 }
 
 
 namespace v8 { namespace internal {
 
   intptr_t HeapObjectTagMask() { return kHeapObjectTagMask; }
 
 } }  // namespace v8::internal