Guard against entering a noSuchMethod dispatcher twice into ICData.

runtime/vm/code_generator.cc

 // Copyright (c) 2013, 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/code_generator.h"
 
 #include "vm/assembler.h"
 #include "vm/ast.h"
 #include "vm/bigint_operations.h"
 #include "vm/code_patcher.h"
@@ skipping 1236 matching lines @@
                                 receiver_class,
                                 target_name,
                                 args_descriptor,
                                 args,
                                 &result)) {
     ArgumentsDescriptor desc(args_descriptor);
     const Function& target_function = Function::Handle(
         receiver_class.GetNoSuchMethodDispatcher(target_name, args_descriptor));
     // Update IC data.
     ASSERT(!target_function.IsNull());
+    intptr_t receiver_cid = receiver.GetClassId();
     if (ic_data.num_args_tested() == 1) {

[srdjan, 2013/07/12 14:45:12]

Add a TODO as discussed in the the CL text.

[Florian Schneider, 2013/07/12 15:43:59]

Done. There is a TODO below about that.

-      ic_data.AddReceiverCheck(receiver.GetClassId(), target_function);
+      // In optimized code we may enter into here via the
+      // MegamorphicCacheMissHandler since noSuchMethod dispatchers are not
+      // inserted into the megamorphic cache. Therefore, we need to guard
+      // against entering the same check twice into the ICData.
+      // Note that num_args_tested == 1 in optimized code.
+      // TODO(fschneider): Handle extraordinary cases like noSuchMethod and
+      // implicit closure invocation properly in the megamorphic cache.
+      const Function& target =
+          Function::Handle(ic_data.GetTargetForReceiverClassId(receiver_cid));
+      if (target.IsNull()) {
+        ic_data.AddReceiverCheck(receiver_cid, target_function);
+      }
     } else {
       // Operators calls have two or three arguments tested ([], []=, etc.)
       ASSERT(ic_data.num_args_tested() > 1);
       GrowableArray<intptr_t> class_ids(ic_data.num_args_tested());
-      class_ids.Add(receiver.GetClassId());
+      class_ids.Add(receiver_cid);
       for (intptr_t i = 1; i < ic_data.num_args_tested(); ++i) {
         class_ids.Add(Object::Handle(args.At(i)).GetClassId());
       }
       ic_data.AddCheck(class_ids, target_function);
     }
     if (FLAG_trace_ic) {
       OS::PrintErr("NoSuchMethod IC miss: adding <%s> id:%"Pd" -> <%s>\n",
           Class::Handle(receiver.clazz()).ToCString(),
-          receiver.GetClassId(),
+          receiver_cid,
           target_function.ToCString());
     }
     result = DartEntry::InvokeFunction(target_function, args, args_descriptor);
   }
   CheckResultError(result);
   arguments.SetReturn(result);
 }
 
 
 static bool CanOptimizeFunction(const Function& function, Isolate* isolate) {
@@ skipping 586 matching lines @@
 //   Arg1: Value that is being stored.
 DEFINE_RUNTIME_ENTRY(UpdateFieldCid, 2) {
   ASSERT(arguments.ArgCount() == kUpdateFieldCidRuntimeEntry.argument_count());
   const Field& field = Field::CheckedHandle(arguments.ArgAt(0));
   const Object& value = Object::Handle(arguments.ArgAt(1));
 
   field.UpdateCid(value.GetClassId());
 }
 
 }  // namespace dart