Polymorphism support for load IC.

src/type-info.cc

Index: src/type-info.cc
diff --git a/src/type-info.cc b/src/type-info.cc
index 1acd8c63b1f09594ae03c9bcdc866715802cfadd..12f8de69b109f5925c6444f24f6478181930780e 100644
--- a/src/type-info.cc
+++ b/src/type-info.cc
@@ -308,6 +308,7 @@ bool TypeFeedbackOracle::LoadIsStub(Property* expr, ICStub* stub) {
   if (!object->IsCode()) return false;
   Handle<Code> code = Handle<Code>::cast(object);
   if (!code->is_load_stub()) return false;
+  if (code->ic_state() != MONOMORPHIC) return false;
   return stub->Describes(*code);
 }
 
@@ -497,6 +498,13 @@ void TypeFeedbackOracle::CollectReceiverTypes(TypeFeedbackId ast_id,
     ASSERT(Handle<Code>::cast(object)->ic_state() == GENERIC);
   } else if (object->IsMap()) {
     types->Add(Handle<Map>::cast(object), zone());
+  } else if (Handle<Code>::cast(object)->ic_state() == POLYMORPHIC) {
+    MapHandleList maps;
+    Handle<Code>::cast(object)->FindAllMaps(&maps);
+    types->Reserve(maps.length(), zone());
+    for (int i = 0; i < maps.length(); i++) {
+      types->Add(maps.at(i), zone());

[Jakob Kummerow, 2013/03/01 22:21:04]

Please compare this with CollectKeyedReceiverTypes() below. In particular,
you'll want the !CanRetainOtherContext() check here as well.
Bonus points for more unification of the two methods (use FindAllMaps below? Or
factor out the code object walking into yet another helper function that fills a
SmallMapList* directly and does the context-retaining check?), but that's
optional ;-)

[Toon Verwaest, 2013/03/04 10:54:08]

Done.

+    }
   } else if (FLAG_collect_megamorphic_maps_from_stub_cache &&
       Handle<Code>::cast(object)->ic_state() == MEGAMORPHIC) {
     types->Reserve(4, zone());