ES6 symbols: turn symbols into a proper primitive type

src/code-stubs.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 492 matching lines @@
 
 
 void ToBooleanStub::Types::Print(StringStream* stream) const {
   if (IsEmpty()) stream->Add("None");
   if (Contains(UNDEFINED)) stream->Add("Undefined");
   if (Contains(BOOLEAN)) stream->Add("Bool");
   if (Contains(NULL_TYPE)) stream->Add("Null");
   if (Contains(SMI)) stream->Add("Smi");
   if (Contains(SPEC_OBJECT)) stream->Add("SpecObject");
   if (Contains(STRING)) stream->Add("String");
+  if (Contains(SYMBOL)) stream->Add("Symbol");
   if (Contains(HEAP_NUMBER)) stream->Add("HeapNumber");
 }
 
 
 void ToBooleanStub::Types::TraceTransition(Types to) const {
   if (!FLAG_trace_ic) return;
   char buffer[100];
   NoAllocationStringAllocator allocator(buffer,
                                         static_cast<unsigned>(sizeof(buffer)));
   StringStream stream(&allocator);
@@ skipping 19 matching lines @@
   } else if (object->IsSmi()) {
     Add(SMI);
     return Smi::cast(*object)->value() != 0;
   } else if (object->IsSpecObject()) {
     Add(SPEC_OBJECT);
     return !object->IsUndetectableObject();
   } else if (object->IsString()) {
     Add(STRING);
     return !object->IsUndetectableObject() &&
         String::cast(*object)->length() != 0;
+  } else if (object->IsSymbol()) {
+    Add(SYMBOL);
+    return true;
   } else if (object->IsHeapNumber()) {
     ASSERT(!object->IsUndetectableObject());
     Add(HEAP_NUMBER);
     double value = HeapNumber::cast(*object)->value();
     return value != 0 && !isnan(value);
   } else {
     // We should never see an internal object at runtime here!
     UNREACHABLE();
     return true;
   }
 }
 
 
 bool ToBooleanStub::Types::NeedsMap() const {
   return Contains(ToBooleanStub::SPEC_OBJECT)
       || Contains(ToBooleanStub::STRING)
+      || Contains(ToBooleanStub::SYMBOL)
       || Contains(ToBooleanStub::HEAP_NUMBER);
 }
 
 
 bool ToBooleanStub::Types::CanBeUndetectable() const {
   return Contains(ToBooleanStub::SPEC_OBJECT)
       || Contains(ToBooleanStub::STRING);
 }
 
 
@@ skipping 58 matching lines @@
   // already active, as the hooks won't stack.
   if (entry_hook != 0 && entry_hook_ != 0)
     return false;
 
   entry_hook_ = entry_hook;
   return true;
 }
 
 
 } }  // namespace v8::internal