Use the return value of vm native methods to set the return value,

vm/native_entry.h

 // 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.
 
 #ifndef VM_NATIVE_ENTRY_H_
 #define VM_NATIVE_ENTRY_H_
 
 #include "vm/allocation.h"
 #include "vm/assembler.h"
 #include "vm/exceptions.h"
 #include "vm/native_arguments.h"
 #include "vm/verifier.h"
 
 #include "include/dart_api.h"
 
 namespace dart {
 
 DECLARE_FLAG(bool, trace_natives);
 
 // Forward declarations.
 class Class;
 class String;
 
 typedef void (*NativeFunction)(NativeArguments* arguments);
 
 
-#define NATIVE_ENTRY_FUNCTION(name) DN_##name
-
-
-// Helper macros for declaring and defining native entries.
-#define REGISTER_NATIVE_ENTRY(name, count)                                     \
-  { ""#name, NATIVE_ENTRY_FUNCTION(name), count },
+#define NATIVE_ENTRY_FUNCTION(name) BootstrapNatives::DN_##name
 
 
 #define DEFINE_NATIVE_ENTRY(name, argument_count)                              \
-  static void DN_Helper##name(Isolate* isolate, NativeArguments* arguments);   \
-  void NATIVE_ENTRY_FUNCTION(name)(Dart_NativeArguments args) {                \
+  static RawObject* DN_Helper##name(Isolate* isolate,                          \
+                                    NativeArguments* arguments);               \
+  void NATIVE_ENTRY_FUNCTION(name)(Dart_NativeArguments args) {         \
     CHECK_STACK_ALIGNMENT;                                                     \
     VERIFY_ON_TRANSITION;                                                      \
     NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);     \
     ASSERT(arguments->Count() == argument_count);                              \
     if (FLAG_trace_natives) OS::Print("Calling native: %s\n", ""#name);        \
     {                                                                          \
       Zone zone(arguments->isolate());                                         \
       HANDLESCOPE(arguments->isolate());                                       \
-      DN_Helper##name(arguments->isolate(), arguments);                        \
+      arguments->SetReturnUnsafe(                                              \
+          DN_Helper##name(arguments->isolate(), arguments));                   \
     }                                                                          \
     VERIFY_ON_TRANSITION;                                                      \
   }                                                                            \
-  static void DN_Helper##name(Isolate* isolate, NativeArguments* arguments)
+  static RawObject* DN_Helper##name(Isolate* isolate,                          \
+                                    NativeArguments* arguments)
 
 
-#define DECLARE_NATIVE_ENTRY(name, argument_count)                             \
-  extern void NATIVE_ENTRY_FUNCTION(name)(Dart_NativeArguments arguments);
-
 // Natives should throw an exception if an illegal argument is passed.
 // type name = value.
 #define GET_NATIVE_ARGUMENT(type, name, value)                                 \
   const Instance& __##name##_instance__ =                                      \
       Instance::CheckedHandle(isolate, value);                                 \
   if (!__##name##_instance__.Is##type()) {                                     \
     GrowableArray<const Object*> __args__;                                     \
     __args__.Add(&__##name##_instance__);                                      \
     Exceptions::ThrowByType(Exceptions::kIllegalArgument, __args__);           \
   }                                                                            \
   const type& name = type::Cast(__##name##_instance__);
 
 
 
 // Helper class for resolving and handling native functions.
 class NativeEntry : public AllStatic {
  public:
   // Resolve specified dart native function to the actual native entrypoint.
   static NativeFunction ResolveNative(const Class& cls,
                                       const String& function_name,
                                       int number_of_arguments);
 };
 
 }  // namespace dart
 
 #endif  // VM_NATIVE_ENTRY_H_