Polymorphism support for load IC.

src/type-info.cc

 // Copyright 2012 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 290 matching lines @@
   return *GetInfo(expr->PropertyFeedbackId()) ==
       isolate_->builtins()->builtin(id);
 }
 
 
 bool TypeFeedbackOracle::LoadIsStub(Property* expr, ICStub* stub) {
   Handle<Object> object = GetInfo(expr->PropertyFeedbackId());
   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);
 }
 
 
 static TypeInfo TypeFromCompareType(CompareIC::State state) {
   switch (state) {
     case CompareIC::UNINITIALIZED:
       // Uninitialized means never executed.
       return TypeInfo::Uninitialized();
     case CompareIC::SMI:
@@ skipping 169 matching lines @@
                                               SmallMapList* types) {
   Handle<Object> object = GetInfo(ast_id);
   if (object->IsUndefined() || object->IsSmi()) return;
 
   if (object.is_identical_to(isolate_->builtins()->StoreIC_GlobalProxy())) {
     // TODO(fschneider): We could collect the maps and signal that
     // we need a generic store (or load) here.
     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());
     ASSERT(object->IsCode());
     isolate_->stub_cache()->CollectMatchingMaps(types,
                                                 *name,
                                                 flags,
                                                 native_context_,
                                                 zone());
   }
@@ skipping 200 matching lines @@
   USE(maybe_result);
 #ifdef DEBUG
   Object* result = NULL;
   // Dictionary has been allocated with sufficient size for all elements.
   ASSERT(maybe_result->ToObject(&result));
   ASSERT(*dictionary_ == result);
 #endif
 }
 
 } }  // namespace v8::internal