Add support for leaf runtime calls

vm/runtime_entry_test.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/runtime_entry.h"
 
 #include "vm/object.h"
 #include "vm/verifier.h"
 
 namespace dart {
@@ skipping 23 matching lines @@
 // Result: a smi representing arg0 - arg1.
 DEFINE_RUNTIME_ENTRY(TestSmiSub, 2) {
   ASSERT(arguments.Count() == kTestSmiSubRuntimeEntry.argument_count());
   const Smi& left = Smi::CheckedHandle(arguments.At(0));
   const Smi& right = Smi::CheckedHandle(arguments.At(1));
   // Ignoring overflow in the calculation below.
   intptr_t result = left.Value() - right.Value();
   arguments.SetReturn(Smi::Handle(Smi::New(result)));
 }
 
+
+// A leaf runtime call for test purposes.
+// Arg0: a smi.
+// Arg1: a smi.
+// returns a smi representing arg0 + arg1.
+DEFINE_LEAF_RUNTIME_ENTRY(TestLeafSmiAdd, 2) {
+  ASSERT(args.Count() == kTestLeafSmiAddRuntimeEntry.argument_count());
+  // Ignoring overflow in the calculation below.
+  intptr_t result = Smi::Value(reinterpret_cast<RawSmi*>(args.At(0))) +
+      Smi::Value(reinterpret_cast<RawSmi*>(args.At(1)));
+  return Smi::New(result);
+}
+
 }  // namespace dart