Provide private symbols through internal APIs

src/objects.cc

 // Copyright 2013 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 1651 matching lines @@
       else if (IsTrue())
         accumulator->Add("<true>");
       else if (IsFalse())
         accumulator->Add("<false>");
       else
         accumulator->Add("<Odd Oddball>");
       break;
     }
     case SYMBOL_TYPE: {
       Symbol* symbol = Symbol::cast(this);
-      accumulator->Add("<Symbol: %d", symbol->Hash());
-      if (!symbol->name()->IsUndefined()) {
+      accumulator->Add("<");
+      accumulator->Add(symbol->IsPrivate() ? "Private" : "Symbol");
+      accumulator->Add(": %d", symbol->Hash());
+      Object* name =
+          symbol->IsPrivate() ? Private::cast(symbol)->name() : symbol->name();
+      if (!name->IsUndefined()) {
         accumulator->Add(" ");
-        String::cast(symbol->name())->StringShortPrint(accumulator);
+        String::cast(name)->StringShortPrint(accumulator);
       }
       accumulator->Add(">");
       break;
     }
     case HEAP_NUMBER_TYPE:
       accumulator->Add("<Number: ");
       HeapNumber::cast(this)->HeapNumberPrint(accumulator);
       accumulator->Put('>');
       break;
     case JS_PROXY_TYPE:
@@ skipping 14710 matching lines @@
 #define ERROR_MESSAGES_TEXTS(C, T) T,
   static const char* error_messages_[] = {
       ERROR_MESSAGES_LIST(ERROR_MESSAGES_TEXTS)
   };
 #undef ERROR_MESSAGES_TEXTS
   return error_messages_[reason];
 }
 
 
 } }  // namespace v8::internal