Remove signature classes from the VM.

runtime/vm/deferred_objects.cc

Index: runtime/vm/deferred_objects.cc
diff --git a/runtime/vm/deferred_objects.cc b/runtime/vm/deferred_objects.cc
index 71a734acaa610ede45e144bff77701bc52cf5955..d3f89c798bec0d09610beba265784c0caeda76ad 100644
--- a/runtime/vm/deferred_objects.cc
+++ b/runtime/vm/deferred_objects.cc
@@ -304,6 +304,48 @@ void DeferredObject::Fill() {
         }
       }
     }
+  } else if (cls.id() == kClosureCid) {
+    // TODO(regis): It would be better to programmatically add these fields to
+    // the VM Closure class. Declaring them in the Dart class _Closure does not
+    // work, because the class is prefinalized and CalculateFieldOffsets is
+    // therefore not called. Resetting the finalization state may be an option.
+    const Closure& closure = Closure::Cast(*object_);
+
+    Smi& offset = Smi::Handle();
+    Object& value = Object::Handle();
+
+    for (intptr_t i = 0; i < field_count_; i++) {
+      offset ^= GetFieldOffset(i);
+      if (offset.Value() == Closure::type_arguments_offset()) {
+        TypeArguments& arguments = TypeArguments::Handle();
+        arguments ^= GetValue(i);
+        closure.SetTypeArguments(arguments);
+        if (FLAG_trace_deoptimization_verbose) {
+          OS::PrintErr("    closure@type_arguments (offset %" Pd ") <- %s\n",
+                       offset.Value(),
+                       value.ToCString());
+        }
+      } else if (offset.Value() == Closure::function_offset()) {
+        Function& function = Function::Handle();
+        function ^= GetValue(i);
+        closure.set_function(function);
+        if (FLAG_trace_deoptimization_verbose) {
+          OS::PrintErr("    closure@function (offset %" Pd ") <- %s\n",
+                       offset.Value(),
+                       value.ToCString());
+        }
+      } else {
+        ASSERT(offset.Value() == Closure::context_offset());
+        Context& context = Context::Handle();
+        context ^= GetValue(i);
+        closure.set_context(context);
+        if (FLAG_trace_deoptimization_verbose) {
+          OS::PrintErr("    closure@context (offset %" Pd ") <- %s\n",
+                       offset.Value(),
+                       value.ToCString());
+        }
+      }
+    }
   } else {
     const Instance& obj = Instance::Cast(*object_);
 
@@ -324,8 +366,7 @@ void DeferredObject::Fill() {
                        value.ToCString());
         }
       } else {
-        ASSERT(cls.IsSignatureClass() ||
-               (offset.Value() == cls.type_arguments_field_offset()));
+        ASSERT(offset.Value() == cls.type_arguments_field_offset());
         obj.SetFieldAtOffset(offset.Value(), value);
         if (FLAG_trace_deoptimization_verbose) {
           OS::PrintErr("    null Field @ offset(%" Pd ") <- %s\n",