Simplify feedback vector creation and store in SharedFunctionInfo.

src/type-info.cc

Index: src/type-info.cc
diff --git a/src/type-info.cc b/src/type-info.cc
index 0ba6dfa852e25118518e3c04273a41d7c02b563e..83eb0da8b6826ffdad64bbd56b0b6dc9aebfa3b2 100644
--- a/src/type-info.cc
+++ b/src/type-info.cc
@@ -43,16 +43,12 @@ namespace internal {
 
 
 TypeFeedbackOracle::TypeFeedbackOracle(Handle<Code> code,
+                                       Handle<FixedArray> feedback_vector,

[Benedikt Meurer, 2014/04/28 19:17:00]

As discussed offline: You'll probably need to duplicate the feedback vector
here, as a GC can clear the type feedback while you are trying to use it. And
add a comment that this can be removed later, once our crappy feedback clearing
during GC is history.

                                        Handle<Context> native_context,
                                        Zone* zone)
     : native_context_(native_context),
-      zone_(zone) {
-  Object* raw_info = code->type_feedback_info();
-  if (raw_info->IsTypeFeedbackInfo()) {
-    feedback_vector_ = Handle<FixedArray>(TypeFeedbackInfo::cast(raw_info)->
-                                          feedback_vector());
-  }
-
+      zone_(zone),
+      feedback_vector_(feedback_vector) {
   BuildDictionary(code);
   ASSERT(dictionary_->IsDictionary());
 }
@@ -136,9 +132,9 @@ bool TypeFeedbackOracle::CallNewIsMonomorphic(int slot) {
 
 byte TypeFeedbackOracle::ForInType(int feedback_vector_slot) {
   Handle<Object> value = GetInfo(feedback_vector_slot);
-  return value->IsSmi() &&
-      Smi::cast(*value)->value() == TypeFeedbackInfo::kForInFastCaseMarker
-          ? ForInStatement::FAST_FOR_IN : ForInStatement::SLOW_FOR_IN;
+  return value.is_identical_to(
+      TypeFeedbackInfo::UninitializedSentinel(isolate()))
+      ? ForInStatement::FAST_FOR_IN : ForInStatement::SLOW_FOR_IN;
 }