Allow Symbols in switch and maps

runtime/vm/object_store.cc

Index: runtime/vm/object_store.cc
===================================================================
--- runtime/vm/object_store.cc	(revision 42183)
+++ runtime/vm/object_store.cc	(working copy)
@@ -38,6 +38,7 @@
     future_class_(Class::null()),
     completer_class_(Class::null()),
     stream_iterator_class_(Class::null()),
+    symbol_class_(Class::null()),
     one_byte_string_class_(Class::null()),
     two_byte_string_class_(Class::null()),
     external_one_byte_string_class_(Class::null()),
@@ -170,7 +171,7 @@
 }
 
 
-void ObjectStore::InitAsyncObjects() {
+void ObjectStore::InitKnownObjects() {
   Isolate* isolate = Isolate::Current();
   ASSERT(isolate != NULL && isolate->object_store() == this);
 
@@ -186,6 +187,10 @@
   cls = async_lib.LookupClass(Symbols::StreamIterator());
   ASSERT(!cls.IsNull());
   set_stream_iterator_class(cls);
+
+  const Library& internal_lib = Library::Handle(internal_library());
+  cls = internal_lib.LookupClass(Symbols::Symbol());
+  set_symbol_class(cls);

[regis, 2014/12/09 21:58:55]

There are many other "known objects" that are looked up and stored in the object
store, e.g. class ClassID. Is class Symbol special?

Doing it here is fine with me, but why not handle all such objects in the same
location?

[hausner, 2014/12/10 00:23:27]

The only reason I'm aware of to do it here is that the objects initialized here
are not allocated programmatically by the VM, since they don't have a
corresponding C++ class. I introduced this for objects from the async library,
but now there's also class Symbol from the internal core library.

We could change this code so the objects are allocated on demand only when the
VM accesses them. I would do this as a separate change.

 }
 
 }  // namespace dart