Implement automatic loading of dart:core_native_fields library

vm/class_finalizer.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/class_finalizer.h"
 
 #include "vm/flags.h"
 #include "vm/heap.h"
 #include "vm/isolate.h"
 #include "vm/longjump.h"
@@ skipping 981 matching lines @@
   }
   // Mark as finalized before resolving type parameter upper bounds and member
   // types in order to break cycles.
   cls.Finalize();
   ResolveAndFinalizeUpperBounds(cls);
   ResolveAndFinalizeMemberTypes(cls);
   // Run additional checks after all types are finalized.
   if (cls.is_const()) {
     CheckForLegalConstClass(cls);
   }
+  // Check to ensure we don't have classes with native fields in libraries
+  // which do not have a native resolver.
+  if (cls.num_native_fields() != 0) {
+    const Library& lib = Library::Handle(cls.library());
+    if (lib.native_entry_resolver() == NULL) {
+      const String& cls_name = String::Handle(cls.Name());
+      const String& lib_name = String::Handle(lib.url());
+      ReportError("class '%s' is trying to extend a native fields class,"
+                  "but library '%s' has no native resolvers",
+                  cls_name.ToCString(), lib_name.ToCString());
+    }
+  }
 }
 
 
 bool ClassFinalizer::IsSuperCycleFree(const Class& cls) {
   Class& test1 = Class::Handle(cls.raw());
   Class& test2 = Class::Handle(cls.SuperClass());
   // A finalized class has been checked for cycles.
   // Using the hare and tortoise algorithm for locating cycles.
   while (!test1.is_finalized() &&
          !test2.IsNull() && !test2.is_finalized()) {
@@ skipping 250 matching lines @@
   va_end(args);
   if (FLAG_warning_as_error) {
     isolate->long_jump_base()->Jump(1, msg_buffer);
     UNREACHABLE();
   } else {
     OS::Print(msg_buffer);
   }
 }
 
 }  // namespace dart