ES6 symbols: Introduce Symbol class, along with abstract Name class

src/objects.cc

 // Copyright 2012 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 1300 matching lines @@
       else if (IsNull())
         accumulator->Add("<null>");
       else if (IsTrue())
         accumulator->Add("<true>");
       else if (IsFalse())
         accumulator->Add("<false>");
       else
         accumulator->Add("<Odd Oddball>");
       break;
     }
+    case SYMBOL_TYPE:
+      accumulator->Add("<Symbol: %d>", Symbol::cast(this)->Hash());
+      break;
     case HEAP_NUMBER_TYPE:
       accumulator->Add("<Number: ");
       HeapNumber::cast(this)->HeapNumberPrint(accumulator);
       accumulator->Put('>');
       break;
     case JS_PROXY_TYPE:
       accumulator->Add("<JSProxy>");
       break;
     case JS_FUNCTION_PROXY_TYPE:
       accumulator->Add("<JSFunctionProxy>");
@@ skipping 88 matching lines @@
       break;
     case MAP_TYPE:
       Map::BodyDescriptor::IterateBody(this, v);
       break;
     case CODE_TYPE:
       reinterpret_cast<Code*>(this)->CodeIterateBody(v);
       break;
     case JS_GLOBAL_PROPERTY_CELL_TYPE:
       JSGlobalPropertyCell::BodyDescriptor::IterateBody(this, v);
       break;
+    case SYMBOL_TYPE:
     case HEAP_NUMBER_TYPE:
     case FILLER_TYPE:
     case BYTE_ARRAY_TYPE:
     case FREE_SPACE_TYPE:
     case EXTERNAL_PIXEL_ARRAY_TYPE:
     case EXTERNAL_BYTE_ARRAY_TYPE:
     case EXTERNAL_UNSIGNED_BYTE_ARRAY_TYPE:
     case EXTERNAL_SHORT_ARRAY_TYPE:
     case EXTERNAL_UNSIGNED_SHORT_ARRAY_TYPE:
     case EXTERNAL_INT_ARRAY_TYPE:
@@ skipping 12458 matching lines @@
   set_year(Smi::FromInt(year), SKIP_WRITE_BARRIER);
   set_month(Smi::FromInt(month), SKIP_WRITE_BARRIER);
   set_day(Smi::FromInt(day), SKIP_WRITE_BARRIER);
   set_weekday(Smi::FromInt(weekday), SKIP_WRITE_BARRIER);
   set_hour(Smi::FromInt(hour), SKIP_WRITE_BARRIER);
   set_min(Smi::FromInt(min), SKIP_WRITE_BARRIER);
   set_sec(Smi::FromInt(sec), SKIP_WRITE_BARRIER);
 }
 
 } }  // namespace v8::internal