For megamorphic calls (IC calls in optimized code), use a stub without attempting to count usage of…

runtime/vm/flow_graph_compiler.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 "vm/globals.h"  // Needed here to get TARGET_ARCH_XXX.
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
@@ skipping 459 matching lines @@
 
 void FlowGraphCompiler::GenerateInstanceCall(
     intptr_t deopt_id,
     intptr_t token_pos,
     intptr_t argument_count,
     const Array& argument_names,
     LocationSummary* locs,
     const ICData& ic_data) {
   ASSERT(!ic_data.IsNull());
   ASSERT(FLAG_propagate_ic_data || (ic_data.NumberOfChecks() == 0));
-  // Because optimized code should not waste time.
-  ASSERT(!is_optimizing() || ic_data.num_args_tested() == 1);
   const Array& arguments_descriptor =
       DartEntry::ArgumentsDescriptor(argument_count, argument_names);
   uword label_address = 0;
-  switch (ic_data.num_args_tested()) {
-    case 1:
-      label_address = StubCode::OneArgCheckInlineCacheEntryPoint();
-      break;
-    case 2:
-      label_address = StubCode::TwoArgsCheckInlineCacheEntryPoint();
-      break;
-    case 3:
-      label_address = StubCode::ThreeArgsCheckInlineCacheEntryPoint();
-      break;
-    default:
-      UNIMPLEMENTED();
+  if (is_optimizing()) {
+    // Megamorphic call requires one argument ICData.
+    ASSERT(ic_data.num_args_tested() == 1);
+    label_address = StubCode::MegamorphicCallEntryPoint();
+  } else {
+    switch (ic_data.num_args_tested()) {
+      case 1:
+        label_address = StubCode::OneArgCheckInlineCacheEntryPoint();
+        break;
+      case 2:
+        label_address = StubCode::TwoArgsCheckInlineCacheEntryPoint();
+        break;
+      case 3:
+        label_address = StubCode::ThreeArgsCheckInlineCacheEntryPoint();
+        break;
+      default:
+        UNIMPLEMENTED();
+    }
   }
   ExternalLabel target_label("InlineCache", label_address);
 
   EmitInstanceCall(&target_label, ic_data, arguments_descriptor, argument_count,
                    deopt_id, token_pos, locs);
 }
 
 
 void FlowGraphCompiler::GenerateStaticCall(intptr_t deopt_id,
                                            intptr_t token_pos,
@@ skipping 411 matching lines @@
       ASSERT(Utils::IsInt(31, disp));
       return FieldAddress(array, disp);
     }
     default:
       UNIMPLEMENTED();
       return FieldAddress(SPREG, 0);
   }
 }
 
 }  // namespace dart