Upgrade Symbol implementation to match current ES6 behavior.

src/runtime.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 611 matching lines @@
   Handle<Object> name(args[0], isolate);
   RUNTIME_ASSERT(name->IsString() || name->IsUndefined());
   Symbol* symbol;
   MaybeObject* maybe = isolate->heap()->AllocatePrivateSymbol();
   if (!maybe->To(&symbol)) return maybe;
   if (name->IsString()) symbol->set_name(*name);
   return symbol;
 }
 
 
-RUNTIME_FUNCTION(MaybeObject*, Runtime_SymbolName) {
+RUNTIME_FUNCTION(MaybeObject*, Runtime_NewSymbolWrapper) {
+  ASSERT(args.length() == 1);
+  CONVERT_ARG_CHECKED(Symbol, symbol, 0);
+  return symbol->ToObject(isolate);
+}
+
+
+RUNTIME_FUNCTION(MaybeObject*, Runtime_SymbolDescription) {
   SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(Symbol, symbol, 0);
   return symbol->name();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SymbolIsPrivate) {
   SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
@@ skipping 10683 matching lines @@
 
   // Add the value being returned.
   if (at_return) {
     details->set(details_index++, *return_value);
   }
 
   // Add the receiver (same as in function frame).
   // THIS MUST BE DONE LAST SINCE WE MIGHT ADVANCE
   // THE FRAME ITERATOR TO WRAP THE RECEIVER.
   Handle<Object> receiver(it.frame()->receiver(), isolate);
-  if (!receiver->IsJSObject() &&
-      shared->is_classic_mode() &&
-      !function->IsBuiltin()) {
+  if (receiver->IsSymbol() ||
+      (!receiver->IsJSObject() &&
+       shared->is_classic_mode() &&
+       !function->IsBuiltin())) {
     // If the receiver is not a JSObject and the function is not a
     // builtin or strict-mode we have hit an optimization where a
     // value object is not converted into a wrapped JS objects. To
     // hide this optimization from the debugger, we wrap the receiver
     // by creating correct wrapper object based on the calling frame's
     // native context.
+    // Symbol receivers are always exempted as their (strict) builtins
+    // only work over the wrapped form.
     it.Advance();
     Handle<Context> calling_frames_native_context(
         Context::cast(Context::cast(it.frame()->context())->native_context()));
     ASSERT(!receiver->IsUndefined() && !receiver->IsNull());
     receiver =
         isolate->factory()->ToObject(receiver, calling_frames_native_context);
   }
   details->set(kFrameDetailsReceiverIndex, *receiver);
 
   ASSERT_EQ(details_size, details_index);
@@ skipping 3536 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal