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

lib/array.cc

 // Copyright (c) 2012, 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 "platform/assert.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/assembler.h"
 #include "vm/bigint_operations.h"
 #include "vm/exceptions.h"
 #include "vm/native_entry.h"
@@ skipping 11 matching lines @@
   if (len < 0 || len > Array::kMaxElements) {
     const String& error = String::Handle(String::NewFormatted(
         "length (%ld) must be in the range [0..%ld]",
         len, Array::kMaxElements));
     GrowableArray<const Object*> args;
     args.Add(&error);
     Exceptions::ThrowByType(Exceptions::kIllegalArgument, args);
   }
   const Array& new_array = Array::Handle(Array::New(length.Value()));
   new_array.SetTypeArguments(type_arguments);
-  arguments->SetReturn(new_array);
+  return new_array.raw();
 }
 
 
 DEFINE_NATIVE_ENTRY(ObjectArray_getIndexed, 2) {
   const Array& array = Array::CheckedHandle(arguments->At(0));
   GET_NATIVE_ARGUMENT(Smi, index, arguments->At(1));
   if ((index.Value() < 0) || (index.Value() >= array.Length())) {
     GrowableArray<const Object*> arguments;
     arguments.Add(&index);
     Exceptions::ThrowByType(Exceptions::kIndexOutOfRange, arguments);
   }
-  const Instance& obj = Instance::CheckedHandle(array.At(index.Value()));
-  arguments->SetReturn(obj);
+  return array.At(index.Value());
 }
 
 
 DEFINE_NATIVE_ENTRY(ObjectArray_setIndexed, 3) {
   const Array& array = Array::CheckedHandle(arguments->At(0));
   GET_NATIVE_ARGUMENT(Smi, index, arguments->At(1));
   const Instance& value = Instance::CheckedHandle(arguments->At(2));
   if ((index.Value() < 0) || (index.Value() >= array.Length())) {
     GrowableArray<const Object*> arguments;
     arguments.Add(&index);
     Exceptions::ThrowByType(Exceptions::kIndexOutOfRange, arguments);
   }
   array.SetAt(index.Value(), value);
+  return Object::null();
 }
 
 
 DEFINE_NATIVE_ENTRY(ObjectArray_getLength, 1) {
   const Array& array = Array::CheckedHandle(arguments->At(0));
-  const Smi& length = Smi::Handle(Smi::New(array.Length()));
-  arguments->SetReturn(length);
+  return Smi::New(array.Length());
 }
 
 
 // ObjectArray src, int srcStart, int dstStart, int count.
 DEFINE_NATIVE_ENTRY(ObjectArray_copyFromObjectArray, 5) {
   const Array& dest = Array::CheckedHandle(arguments->At(0));
   GET_NATIVE_ARGUMENT(Array, source, arguments->At(1));
   GET_NATIVE_ARGUMENT(Smi, src_start, arguments->At(2));
   GET_NATIVE_ARGUMENT(Smi, dst_start, arguments->At(3));
   GET_NATIVE_ARGUMENT(Smi, count, arguments->At(4));
   intptr_t icount = count.Value();
   if (icount < 0) {
     GrowableArray<const Object*> args;
     Exceptions::ThrowByType(Exceptions::kIllegalArgument, args);
   }
   if (icount == 0) {
-    return;
+    return Object::null();
   }
   intptr_t isrc_start = src_start.Value();
   intptr_t idst_start = dst_start.Value();
   if ((isrc_start < 0) || ((isrc_start + icount) > source.Length())) {
     GrowableArray<const Object*> arguments;
     arguments.Add(&src_start);
     Exceptions::ThrowByType(Exceptions::kIndexOutOfRange, arguments);
   }
   if ((idst_start < 0) || ((idst_start + icount) > dest.Length())) {
     GrowableArray<const Object*> arguments;
     arguments.Add(&dst_start);
     Exceptions::ThrowByType(Exceptions::kIndexOutOfRange, arguments);
   }
 
   Object& src_obj = Object::Handle();
   if (isrc_start < idst_start) {
     for (intptr_t i = icount - 1; i >= 0; i--) {
       src_obj = source.At(isrc_start + i);
       dest.SetAt(idst_start + i, src_obj);
     }
   } else {
     for (intptr_t i = 0; i < icount; i++) {
       src_obj = source.At(isrc_start + i);
       dest.SetAt(idst_start + i, src_obj);
     }
   }
+  return Object::null();
 }
 
 }  // namespace dart