Implement argument definition test in the vm.

runtime/vm/flow_graph_builder.cc

Index: runtime/vm/flow_graph_builder.cc
===================================================================
--- runtime/vm/flow_graph_builder.cc	(revision 11663)
+++ runtime/vm/flow_graph_builder.cc	(working copy)
@@ -1322,6 +1322,16 @@
 }
 
 
+void EffectGraphVisitor::VisitArgumentDefinitionTestNode(
+    ArgumentDefinitionTestNode* node) {
+  Computation* load = BuildLoadLocal(node->saved_arguments_descriptor());
+  Value* arguments_descriptor = Bind(load);
+  ArgumentDefinitionTestComp* arg_def_test =
+      new ArgumentDefinitionTestComp(node, arguments_descriptor);
+  ReturnComputation(arg_def_test);
+}
+
+
 void EffectGraphVisitor::VisitArrayNode(ArrayNode* node) {
   InlineBailout("EffectGraphVisitor::VisitArrayNode");
   // Translate the array elements and collect their values.
@@ -1354,6 +1364,7 @@
     // The context scope may have already been set by the non-optimizing
     // compiler.  If it was not, set it here.
     if (function.context_scope() == ContextScope::null()) {
+      // TODO(regis): Why are we not doing this in the parser?
       const ContextScope& context_scope = ContextScope::ZoneHandle(
           node->scope()->PreserveOuterScope(owner()->context_level()));
       ASSERT(!function.HasCode());
@@ -2233,9 +2244,14 @@
     if (node == owner()->parsed_function().node_sequence()) {
       ASSERT(scope->context_level() == 1);
       const Function& function = owner()->parsed_function().function();
-      const int num_params = function.NumberOfParameters();
+      int num_params = function.NumberOfParameters();
       int param_frame_index = (num_params == function.num_fixed_parameters()) ?
           (1 + num_params) : ParsedFunction::kFirstLocalSlotIndex;
+      // Handle the saved arguments descriptor as an additional parameter.
+      if (owner()->parsed_function().GetSavedArgumentsDescriptorVar() != NULL) {
+        ASSERT(param_frame_index == ParsedFunction::kFirstLocalSlotIndex);
+        num_params++;
+      }
       for (int pos = 0; pos < num_params; param_frame_index--, pos++) {
         const LocalVariable& parameter = *scope->VariableAt(pos);
         ASSERT(parameter.owner() == scope);