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..04e909bd6fe3f94ea6c064cc883e7670a7f3c396 100644
--- a/src/type-info.cc
+++ b/src/type-info.cc
@@ -43,18 +43,18 @@ namespace internal {
 
 
 TypeFeedbackOracle::TypeFeedbackOracle(Handle<Code> code,
+                                       Handle<FixedArray> feedback_vector,
                                        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());
-  }
-
   BuildDictionary(code);
   ASSERT(dictionary_->IsDictionary());
+  // We make a copy of the feedback vector because a GC could clear
+  // the type feedback info contained therein.
+  // TODO(mvstanton): revisit the decision to copy when we weakly
+  // traverse the feedback vector at GC time.
+  feedback_vector_ = isolate()->factory()->CopyFixedArray(feedback_vector);
 }
 
 
@@ -136,9 +136,9 @@ 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;
 }