Add support for per-isolate private symbols

src/runtime.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
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 // modification, are permitted provided that the following conditions are
 // met:
 //
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@@ skipping 603 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_CreateGlobalPrivateSymbol) {
+  HandleScope scope(isolate);
+  ASSERT(args.length() == 1);
+  CONVERT_ARG_HANDLE_CHECKED(String, name, 0);
+  Handle<JSObject> registry = handle(isolate->heap()->symbol_registry());
+  Handle<String> part = handle(isolate->heap()->private_intern_string());
+  Handle<Object> privates_val = JSReceiver::GetProperty(registry, part);
+  Handle<JSObject> privates;
+  if (privates_val->IsJSObject()) {
+    privates = Handle<JSObject>::cast(privates_val);
+  } else {
+    ASSERT(privates_val->IsUndefined());
+    privates =
+        isolate->factory()->NewJSObject(isolate->object_function(), TENURED);

[Michael Starzinger, 2014/03/24 10:04:33]

As discussed offline: This will create a JSObject bound to a specific context
(i.e. obj->map->constructor) and hence keep the native context which happened to
trigger this lazy initialization alive forever.

And you are right, we have the same problem already in the lazy initialization
in the symbol.js file.

[rossberg, 2014/03/24 15:09:49]

I moved the whole registry creation and initialization to a new method
Isolate::GetSymbolRegistry, which is now shared by all relevant code sites.

+    JSObject::SetPrototype(privates, isolate->factory()->null_value());
+    JSObject::SetProperty(registry, part, privates, NONE, STRICT);
+  }
+  Handle<Object> symbol = JSObject::GetProperty(privates, name);
+  if (!symbol->IsSymbol()) {
+    ASSERT(symbol->IsUndefined());
+    symbol = isolate->factory()->NewPrivateSymbol();
+    Handle<Symbol>::cast(symbol)->set_name(*name);
+    JSObject::SetProperty(privates, name, symbol, NONE, STRICT);
+  }
+  return *symbol;
+}
+
+
 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);
@@ skipping 14426 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