Second attempt: Improve our type feedback by recogizining never-executed IC c...

src/type-info.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 124 matching lines @@
 TypeInfo TypeFeedbackOracle::CompareType(CompareOperation* expr, Side side) {
   Handle<Object> object = GetElement(map_, expr->position());
   TypeInfo unknown = TypeInfo::Unknown();
   if (!object->IsCode()) return unknown;
   Handle<Code> code = Handle<Code>::cast(object);
   if (!code->is_compare_ic_stub()) return unknown;
 
   CompareIC::State state = static_cast<CompareIC::State>(code->compare_state());
   switch (state) {
     case CompareIC::UNINITIALIZED:
+      // Uninitialized means never executed.
+      // TODO(fschneider): Introduce a separate value for never-executed ICs.
+      return unknown;
     case CompareIC::SMIS:
       return TypeInfo::Smi();
     case CompareIC::HEAP_NUMBERS:
       return TypeInfo::Number();
     case CompareIC::OBJECTS:
       // TODO(kasperl): We really need a type for JS objects here.
       return TypeInfo::NonPrimitive();
     case CompareIC::GENERIC:
     default:
       return unknown;
@@ skipping 22 matching lines @@
         return unknown;
     }
   } else if (code->is_type_recording_binary_op_stub()) {
     TRBinaryOpIC::TypeInfo type = static_cast<TRBinaryOpIC::TypeInfo>(
         code->type_recording_binary_op_type());
     TRBinaryOpIC::TypeInfo result_type = static_cast<TRBinaryOpIC::TypeInfo>(
         code->type_recording_binary_op_result_type());
 
     switch (type) {
       case TRBinaryOpIC::UNINITIALIZED:
+        // Uninitialized means never executed.
+        // TODO(fschneider): Introduce a separate value for never-executed ICs
+        return unknown;
       case TRBinaryOpIC::SMI:
         switch (result_type) {
           case TRBinaryOpIC::UNINITIALIZED:
           case TRBinaryOpIC::SMI:
             return TypeInfo::Smi();
           case TRBinaryOpIC::INT32:
             return TypeInfo::Integer32();
           case TRBinaryOpIC::HEAP_NUMBER:
             return TypeInfo::Double();
           default:
@@ skipping 20 matching lines @@
 TypeInfo TypeFeedbackOracle::SwitchType(CaseClause* clause) {
   Handle<Object> object = GetElement(map_, clause->position());
   TypeInfo unknown = TypeInfo::Unknown();
   if (!object->IsCode()) return unknown;
   Handle<Code> code = Handle<Code>::cast(object);
   if (!code->is_compare_ic_stub()) return unknown;
 
   CompareIC::State state = static_cast<CompareIC::State>(code->compare_state());
   switch (state) {
     case CompareIC::UNINITIALIZED:
+      // Uninitialized means never executed.
+      // TODO(fschneider): Introduce a separate value for never-executed ICs.
+      return unknown;
     case CompareIC::SMIS:
       return TypeInfo::Smi();
     case CompareIC::HEAP_NUMBERS:
       return TypeInfo::Number();
     case CompareIC::OBJECTS:
       // TODO(kasperl): We really need a type for JS objects here.
       return TypeInfo::NonPrimitive();
     case CompareIC::GENERIC:
     default:
       return unknown;
@@ skipping 105 matching lines @@
         source_positions->Add(position);
       }
     } else {
       ASSERT(RelocInfo::IsPosition(mode));
       position = static_cast<int>(info->data());
     }
   }
 }
 
 } }  // namespace v8::internal