Background compiler should validate CHA decisions before committing the code.

runtime/vm/aot_optimizer.cc

Index: runtime/vm/aot_optimizer.cc
diff --git a/runtime/vm/aot_optimizer.cc b/runtime/vm/aot_optimizer.cc
index e81ddfcf532a452187c70abba3fb53679607835b..e755b0c9a444e19c06ac3a0af791979b4cd783ed 100644
--- a/runtime/vm/aot_optimizer.cc
+++ b/runtime/vm/aot_optimizer.cc
@@ -2067,7 +2067,7 @@ bool AotOptimizer::TypeCheckAsClassEquality(const AbstractType& type) {
             type_class.ToCString());
       }
       if (FLAG_use_cha_deopt) {
-        thread()->cha()->AddToLeafClasses(type_class);
+        thread()->cha()->AddToGuardedClasses(type_class, /*subclass_count=*/0);

[Florian Schneider, 2016/05/20 11:23:28]

You can remove this, or add ASSERT(!FLAG_use_cha_deopt) here. This should never
be reached, since use_cha_deopt is hardcoded to false for AOT.

[Vyacheslav Egorov (Google), 2016/05/20 11:31:21]

Done.

       }
     } else {
       return false;
@@ -2456,8 +2456,10 @@ void AotOptimizer::VisitInstanceCall(InstanceCallInstr* instr) {
             instr->function_name(),
             args_desc));
     if (!function.IsNull()) {
+      intptr_t subclasses = 0;
       if (!thread()->cha()->HasOverride(receiver_class,
-                                        instr->function_name())) {
+                                        instr->function_name(),
+                                        &subclasses)) {
         if (FLAG_trace_cha) {
           THR_Print("  **(CHA) Instance call needs no check, "
               "no overrides of '%s' '%s'\n",