Re-land r8140: Deoptimize on never-executed code-paths.

src/type-info.cc

 // Copyright 2011 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 206 matching lines @@
   Handle<Object> object = GetInfo(expr->id());
   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;
+      return TypeInfo::Uninitialized();
     case CompareIC::SMIS:
       return TypeInfo::Smi();
     case CompareIC::HEAP_NUMBERS:
       return TypeInfo::Number();
     case CompareIC::SYMBOLS:
     case CompareIC::STRINGS:
       return TypeInfo::String();
     case CompareIC::OBJECTS:
       // TODO(kasperl): We really need a type for JS objects here.
       return TypeInfo::NonPrimitive();
@@ skipping 40 matching lines @@
   Handle<Code> code = Handle<Code>::cast(object);
   if (code->is_binary_op_stub()) {
     BinaryOpIC::TypeInfo type = static_cast<BinaryOpIC::TypeInfo>(
         code->binary_op_type());
     BinaryOpIC::TypeInfo result_type = static_cast<BinaryOpIC::TypeInfo>(
         code->binary_op_result_type());
 
     switch (type) {
       case BinaryOpIC::UNINITIALIZED:
         // Uninitialized means never executed.
-        // TODO(fschneider): Introduce a separate value for never-executed ICs
-        return unknown;
+        return TypeInfo::Uninitialized();
       case BinaryOpIC::SMI:
         switch (result_type) {
           case BinaryOpIC::UNINITIALIZED:
           case BinaryOpIC::SMI:
             return TypeInfo::Smi();
           case BinaryOpIC::INT32:
             return TypeInfo::Integer32();
           case BinaryOpIC::HEAP_NUMBER:
             return TypeInfo::Double();
           default:
@@ skipping 197 matching lines @@
           static_cast<int>(info->pc() - code->instruction_start()));
       ASSERT(ast_ids->length() == 0 ||
              (*ast_ids)[ast_ids->length()-1] !=
              static_cast<unsigned>(info->data()));
       ast_ids->Add(static_cast<unsigned>(info->data()));
     }
   }
 }
 
 } }  // namespace v8::internal