Background compiler should validate CHA decisions before committing the code.

runtime/vm/flow_graph.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/flow_graph.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
@@ skipping 426 matching lines @@
     // may later add overriding methods.
     return true;
   }
   Definition* callee_receiver = call->ArgumentAt(0);
   ASSERT(callee_receiver != NULL);
   if (function().IsDynamicFunction() && IsReceiver(callee_receiver)) {
     const String& name = (kind == RawFunction::kMethodExtractor)
         ? String::Handle(zone(), Field::NameFromGetter(call->function_name()))
         : call->function_name();
     const Class& cls = Class::Handle(zone(), function().Owner());
-    if (!thread()->cha()->HasOverride(cls, name)) {
+    intptr_t subclass_count = 0;
+    if (!thread()->cha()->HasOverride(cls, name, &subclass_count)) {
       if (FLAG_trace_cha) {
         THR_Print("  **(CHA) Instance call needs no check, "
             "no overrides of '%s' '%s'\n",
             name.ToCString(), cls.ToCString());
       }
-      thread()->cha()->AddToLeafClasses(cls);
+      thread()->cha()->AddToGuardedClasses(cls, subclass_count);
       return false;
     }
   }
   return true;
 }
 
 
 
 bool FlowGraph::VerifyUseLists() {
   // Verify the initial definitions.
@@ skipping 1583 matching lines @@
         ReplaceCurrentInstruction(&it, current, replacement);
         changed = true;
       }
     }
   }
   return changed;
 }
 
 
 }  // namespace dart