Flesh out vector ic state query and set mechanisms.

src/ic/ic.cc

Index: src/ic/ic.cc
diff --git a/src/ic/ic.cc b/src/ic/ic.cc
index 0c38c2b74112b24eb3893147cf0abaf931f554af..cde608ac9c059dbf74c3131618499351597276e8 100644
--- a/src/ic/ic.cc
+++ b/src/ic/ic.cc
@@ -258,7 +258,11 @@ bool IC::TryRemoveInvalidPrototypeDependentStub(Handle<Object> receiver,
                                                 Handle<String> name) {
   if (!IsNameCompatibleWithPrototypeFailure(name)) return false;
   Handle<Map> receiver_map = TypeToMap(*receiver_type(), isolate());
-  maybe_handler_ = target()->FindHandlerForMap(*receiver_map);
+  if (UseVector()) {
+    maybe_handler_ = nexus()->FindHandlerForMap(receiver_map);
+  } else {
+    maybe_handler_ = target()->FindHandlerForMap(*receiver_map);
+  }
 
   // The current map wasn't handled yet. There's no reason to stay monomorphic,
   // *unless* we're moving from a deprecated map to its replacement, or
@@ -310,7 +314,8 @@ bool IC::IsNameCompatibleWithPrototypeFailure(Handle<Object> name) {
   if (target()->is_keyed_stub()) {
     // Determine whether the failure is due to a name failure.
     if (!name->IsName()) return false;
-    Name* stub_name = target()->FindFirstName();
+    Name* stub_name =
+        UseVector() ? nexus()->FindFirstName() : target()->FindFirstName();
     if (*name != stub_name) return false;
   }
 
@@ -452,7 +457,11 @@ void IC::OnTypeFeedbackChanged(Isolate* isolate, Code* host,
 void IC::PostPatching(Address address, Code* target, Code* old_target) {
   // Type vector based ICs update these statistics at a different time because
   // they don't always patch on state change.
-  if (target->kind() == Code::CALL_IC) return;
+  if (target->kind() == Code::CALL_IC ||
+      (FLAG_vector_ics && (target->kind() == Code::LOAD_IC ||

[Jakob Kummerow, 2014/11/26 15:14:14]

Can you re-use UseVector() here instead of duplicating the condition?

[mvstanton, 2014/11/27 13:09:26]

Done.

+                           target->kind() == Code::KEYED_LOAD_IC))) {
+    return;
+  }
 
   Isolate* isolate = target->GetHeap()->isolate();
   State old_state = UNINITIALIZED;
@@ -514,8 +523,10 @@ void IC::Clear(Isolate* isolate, Address address,
 
   switch (target->kind()) {
     case Code::LOAD_IC:
+      if (FLAG_vector_ics) return;
       return LoadIC::Clear(isolate, address, target, constant_pool);
     case Code::KEYED_LOAD_IC:
+      if (FLAG_vector_ics) return;
       return KeyedLoadIC::Clear(isolate, address, target, constant_pool);
     case Code::STORE_IC:
       return StoreIC::Clear(isolate, address, target, constant_pool);
@@ -537,23 +548,9 @@ void IC::Clear(Isolate* isolate, Address address,
 }
 
 
-template <class Nexus>
-void IC::Clear(Isolate* isolate, Code::Kind kind, Code* host, Nexus* nexus) {
-  switch (kind) {
-    case Code::CALL_IC:
-      return CallIC::Clear(isolate, host, nexus);
-    default:
-      UNREACHABLE();
-  }
-}
-
-
-// Force instantiation of template instances for vector-based IC clearing.
-template void IC::Clear(Isolate*, Code::Kind, Code*, CallICNexus*);
-
-
 void KeyedLoadIC::Clear(Isolate* isolate, Address address, Code* target,
                         ConstantPoolArray* constant_pool) {
+  DCHECK(!FLAG_vector_ics);
   if (IsCleared(target)) return;
 
   // Make sure to also clear the map used in inline fast cases.  If we
@@ -563,6 +560,17 @@ void KeyedLoadIC::Clear(Isolate* isolate, Address address, Code* target,
 }
 
 
+void KeyedLoadIC::Clear(Isolate* isolate, Code* host, KeyedLoadICNexus* nexus) {
+  if (IsCleared(nexus)) return;
+  // Make sure to also clear the map used in inline fast cases.  If we
+  // do not clear these maps, cached code can keep objects alive
+  // through the embedded maps.
+  State state = nexus->StateFromFeedback();
+  nexus->ConfigurePremonomorphic();
+  OnTypeFeedbackChanged(isolate, host, nexus->vector(), state, PREMONOMORPHIC);
+}
+
+
 void CallIC::Clear(Isolate* isolate, Code* host, CallICNexus* nexus) {
   // Determine our state.
   Object* feedback = nexus->vector()->Get(nexus->slot());
@@ -578,6 +586,7 @@ void CallIC::Clear(Isolate* isolate, Code* host, CallICNexus* nexus) {
 
 void LoadIC::Clear(Isolate* isolate, Address address, Code* target,
                    ConstantPoolArray* constant_pool) {
+  DCHECK(!FLAG_vector_ics);
   if (IsCleared(target)) return;
   Code* code = PropertyICCompiler::FindPreMonomorphic(isolate, Code::LOAD_IC,
                                                       target->extra_ic_state());
@@ -585,6 +594,15 @@ void LoadIC::Clear(Isolate* isolate, Address address, Code* target,
 }
 
 
+void LoadIC::Clear(Isolate* isolate, Code* host, LoadICNexus* nexus) {
+  if (IsCleared(nexus)) return;
+  // Determine our state.

[Jakob Kummerow, 2014/11/26 15:14:15]

nit: I don't think this comment adds much value.

[mvstanton, 2014/11/27 13:09:26]

Done.

+  nexus->ConfigurePremonomorphic();
+  State state = nexus->StateFromFeedback();

[Jakob Kummerow, 2014/11/26 15:14:14]

Save the previous state before calling ConfigurePremonomorphic maybe?

[mvstanton, 2014/11/27 13:09:26]

doh! good catch, thanks!

+  OnTypeFeedbackChanged(isolate, host, nexus->vector(), state, PREMONOMORPHIC);
+}
+
+
 void StoreIC::Clear(Isolate* isolate, Address address, Code* target,
                     ConstantPoolArray* constant_pool) {
   if (IsCleared(target)) return;
@@ -635,6 +653,71 @@ static bool MigrateDeprecated(Handle<Object> object) {
 }
 
 
+void IC::ConfigureVectorState(IC::State new_state) {
+  DCHECK(UseVector());
+  if (kind() == Code::LOAD_IC) {
+    LoadICNexus* nexus = casted_nexus<LoadICNexus>();
+    if (new_state == PREMONOMORPHIC) {
+      nexus->ConfigurePremonomorphic();
+    } else if (new_state == MEGAMORPHIC) {
+      nexus->ConfigureMegamorphic();
+    } else {
+      UNREACHABLE();
+    }
+  } else if (kind() == Code::KEYED_LOAD_IC) {
+    KeyedLoadICNexus* nexus = casted_nexus<KeyedLoadICNexus>();
+    if (new_state == GENERIC) {
+      nexus->ConfigureGeneric();
+    } else if (new_state == PREMONOMORPHIC) {
+      nexus->ConfigurePremonomorphic();
+    } else if (new_state == MEGAMORPHIC) {
+      nexus->ConfigureMegamorphic();
+    } else {
+      UNREACHABLE();
+    }
+  } else {
+    UNREACHABLE();
+  }
+
+  OnTypeFeedbackChanged(isolate(), get_host(), *vector(), saved_state(),
+                        new_state);
+}
+
+
+void IC::ConfigureVectorState(Handle<Name> name, Handle<HeapType> type,
+                              Handle<Code> handler) {
+  DCHECK(UseVector());
+  if (kind() == Code::LOAD_IC) {
+    LoadICNexus* nexus = casted_nexus<LoadICNexus>();
+    nexus->ConfigureMonomorphic(type, handler);
+  } else {
+    DCHECK(kind() == Code::KEYED_LOAD_IC);
+    KeyedLoadICNexus* nexus = casted_nexus<KeyedLoadICNexus>();
+    nexus->ConfigureMonomorphic(name, type, handler);
+  }
+
+  OnTypeFeedbackChanged(isolate(), get_host(), *vector(), saved_state(),
+                        MONOMORPHIC);
+}
+
+
+void IC::ConfigureVectorState(Handle<Name> name, TypeHandleList* types,
+                              CodeHandleList* handlers) {
+  DCHECK(UseVector());
+  if (kind() == Code::LOAD_IC) {
+    LoadICNexus* nexus = casted_nexus<LoadICNexus>();
+    nexus->ConfigurePolymorphic(types, handlers);
+  } else {
+    DCHECK(kind() == Code::KEYED_LOAD_IC);
+    KeyedLoadICNexus* nexus = casted_nexus<KeyedLoadICNexus>();
+    nexus->ConfigurePolymorphic(name, types, handlers);
+  }
+
+  OnTypeFeedbackChanged(isolate(), get_host(), *vector(), saved_state(),
+                        POLYMORPHIC);
+}
+
+
 MaybeHandle<Object> LoadIC::Load(Handle<Object> object, Handle<Name> name) {
   // If the object is undefined or null it's illegal to try to get any
   // of its properties; throw a TypeError in that case.
@@ -648,7 +731,11 @@ MaybeHandle<Object> LoadIC::Load(Handle<Object> object, Handle<Name> name) {
   if (kind() == Code::KEYED_LOAD_IC && name->AsArrayIndex(&index)) {
     // Rewrite to the generic keyed load stub.
     if (FLAG_use_ic) {
-      set_target(*KeyedLoadIC::generic_stub(isolate()));
+      if (UseVector()) {
+        ConfigureVectorState(GENERIC);
+      } else {
+        set_target(*KeyedLoadIC::generic_stub(isolate()));
+      }
       TRACE_IC("LoadIC", name);
       TRACE_GENERIC_IC(isolate(), "LoadIC", "name as array index");
     }
@@ -753,14 +840,23 @@ bool IC::UpdatePolymorphicIC(Handle<Name> name, Handle<Code> code) {
 
   if (number_of_valid_types >= 4) return false;
   if (number_of_types == 0) return false;
-  if (!target()->FindHandlers(&handlers, types.length())) return false;
+  if (UseVector()) {
+    if (!nexus()->FindHandlers(&handlers, types.length())) return false;
+  } else {
+    if (!target()->FindHandlers(&handlers, types.length())) return false;
+  }
 
   number_of_valid_types++;
   if (number_of_valid_types > 1 && target()->is_keyed_stub()) return false;
   Handle<Code> ic;
   if (number_of_valid_types == 1) {
-    ic = PropertyICCompiler::ComputeMonomorphic(kind(), name, type, code,
-                                                extra_ic_state());
+    if (UseVector()) {
+      DCHECK(kind() == Code::LOAD_IC || kind() == Code::KEYED_LOAD_IC);

[Jakob Kummerow, 2014/11/26 15:14:15]

You can drop this DCHECK; ConfigureVectorState() contains the same check (and is
what will need to be updated in the future anyway; this call site doesn't need
to care).

[mvstanton, 2014/11/27 13:09:26]

Done.

+      ConfigureVectorState(name, receiver_type(), code);
+    } else {
+      ic = PropertyICCompiler::ComputeMonomorphic(kind(), name, type, code,
+                                                  extra_ic_state());
+    }
   } else {
     if (handler_to_overwrite >= 0) {
       handlers.Set(handler_to_overwrite, code);
@@ -771,11 +867,17 @@ bool IC::UpdatePolymorphicIC(Handle<Name> name, Handle<Code> code) {
       types.Add(type);
       handlers.Add(code);
     }
-    ic = PropertyICCompiler::ComputePolymorphic(kind(), &types, &handlers,
-                                                number_of_valid_types, name,
-                                                extra_ic_state());
+
+    if (UseVector()) {
+      ConfigureVectorState(name, &types, &handlers);
+    } else {
+      ic = PropertyICCompiler::ComputePolymorphic(kind(), &types, &handlers,
+                                                  number_of_valid_types, name,
+                                                  extra_ic_state());
+    }
   }
-  set_target(*ic);
+
+  if (!UseVector()) set_target(*ic);
   return true;
 }
 
@@ -823,9 +925,13 @@ template Handle<HeapType> IC::MapToType<HeapType>(Handle<Map> map,
 
 void IC::UpdateMonomorphicIC(Handle<Code> handler, Handle<Name> name) {
   DCHECK(handler->is_handler());
-  Handle<Code> ic = PropertyICCompiler::ComputeMonomorphic(
-      kind(), name, receiver_type(), handler, extra_ic_state());
-  set_target(*ic);
+  if (UseVector()) {
+    ConfigureVectorState(name, receiver_type(), handler);
+  } else {
+    Handle<Code> ic = PropertyICCompiler::ComputeMonomorphic(
+        kind(), name, receiver_type(), handler, extra_ic_state());
+    set_target(*ic);
+  }
 }
 
 
@@ -870,7 +976,11 @@ void IC::PatchCache(Handle<Name> name, Handle<Code> code) {
         // same key.
         CopyICToMegamorphicCache(name);
       }
-      set_target(*megamorphic_stub());
+      if (UseVector()) {
+        ConfigureVectorState(MEGAMORPHIC);
+      } else {
+        set_target(*megamorphic_stub());
+      }
     // Fall through.
     case MEGAMORPHIC:
       UpdateMegamorphicCache(*receiver_type(), *name, *code);
@@ -893,6 +1003,10 @@ void IC::PatchCache(Handle<Name> name, Handle<Code> code) {
 
 Handle<Code> LoadIC::initialize_stub(Isolate* isolate,
                                      ExtraICState extra_state) {
+  if (FLAG_vector_ics) {
+    return LoadICTrampolineStub(isolate, LoadICState(extra_state)).GetCode();
+  }
+
   return PropertyICCompiler::ComputeLoad(isolate, UNINITIALIZED, extra_state);
 }
 
@@ -936,6 +1050,7 @@ Handle<Code> LoadIC::megamorphic_stub() {
 
 Handle<Code> LoadIC::pre_monomorphic_stub(Isolate* isolate,
                                           ExtraICState extra_state) {
+  DCHECK(!FLAG_vector_ics);
   return PropertyICCompiler::ComputeLoad(isolate, PREMONOMORPHIC, extra_state);
 }
 
@@ -965,7 +1080,11 @@ void LoadIC::UpdateCaches(LookupIterator* lookup) {
   if (state() == UNINITIALIZED) {
     // This is the first time we execute this inline cache. Set the target to
     // the pre monomorphic stub to delay setting the monomorphic state.
-    set_target(*pre_monomorphic_stub());
+    if (UseVector()) {
+      ConfigureVectorState(PREMONOMORPHIC);
+    } else {
+      set_target(*pre_monomorphic_stub());
+    }
     TRACE_IC("LoadIC", lookup->name());
     return;
   }
@@ -1233,6 +1352,12 @@ Handle<Code> KeyedLoadIC::LoadElementStub(Handle<HeapObject> receiver) {
   TargetMaps(&target_receiver_maps);
 
   if (target_receiver_maps.length() == 0) {
+    if (FLAG_vector_ics) {
+      Handle<Code> handler =
+          PropertyICCompiler::ComputeKeyedLoadMonomorphicHandler(receiver_map);
+      ConfigureVectorState(Handle<Name>::null(), receiver_type(), handler);
+      return target();

[Jakob Kummerow, 2014/11/26 15:14:15]

Consider "return Handle<Code>::null();" to make it obvious that the return value
is not supposed to be used for patching?

[mvstanton, 2014/11/27 13:09:26]

I think this use of target() solved a problem for me ("elegantly") at one point
but now it's just strange. I'll go to Handle<Code>::null().

+    }
     return PropertyICCompiler::ComputeKeyedLoadMonomorphic(receiver_map);
   }
 
@@ -1247,6 +1372,12 @@ Handle<Code> KeyedLoadIC::LoadElementStub(Handle<HeapObject> receiver) {
       IsMoreGeneralElementsKindTransition(
           target_receiver_maps.at(0)->elements_kind(),
           Handle<JSObject>::cast(receiver)->GetElementsKind())) {
+    if (FLAG_vector_ics) {
+      Handle<Code> handler =
+          PropertyICCompiler::ComputeKeyedLoadMonomorphicHandler(receiver_map);
+      ConfigureVectorState(Handle<Name>::null(), receiver_type(), handler);
+      return target();
+    }
     return PropertyICCompiler::ComputeKeyedLoadMonomorphic(receiver_map);
   }
 
@@ -1258,6 +1389,10 @@ Handle<Code> KeyedLoadIC::LoadElementStub(Handle<HeapObject> receiver) {
     // If the miss wasn't due to an unseen map, a polymorphic stub
     // won't help, use the generic stub.
     TRACE_GENERIC_IC(isolate(), "KeyedLoadIC", "same map added twice");
+    if (FLAG_vector_ics) {
+      ConfigureVectorState(GENERIC);
+      return target();
+    }
     return generic_stub();
   }
 
@@ -1265,9 +1400,25 @@ Handle<Code> KeyedLoadIC::LoadElementStub(Handle<HeapObject> receiver) {
   // version of the IC.
   if (target_receiver_maps.length() > kMaxKeyedPolymorphism) {
     TRACE_GENERIC_IC(isolate(), "KeyedLoadIC", "max polymorph exceeded");
+    if (FLAG_vector_ics) {
+      ConfigureVectorState(GENERIC);
+      return target();
+    }
     return generic_stub();
   }
 
+  if (FLAG_vector_ics) {
+    CodeHandleList handlers(target_receiver_maps.length());
+    ElementHandlerCompiler compiler(isolate());
+    compiler.CompileElementHandlers(&target_receiver_maps, &handlers);
+    TypeHandleList types(target_receiver_maps.length());
+    for (int i = 0; i < target_receiver_maps.length(); i++) {
+      types.Add(HeapType::Class(target_receiver_maps.at(i), isolate()));
+    }
+    ConfigureVectorState(Handle<Name>::null(), &types, &handlers);
+    return target();
+  }
+
   return PropertyICCompiler::ComputeKeyedLoadPolymorphic(&target_receiver_maps);
 }
 
@@ -1303,11 +1454,14 @@ MaybeHandle<Object> KeyedLoadIC::Load(Handle<Object> object,
   }
 
   if (!is_target_set()) {
-    Code* generic = *generic_stub();
-    if (*stub == generic) {
-      TRACE_GENERIC_IC(isolate(), "KeyedLoadIC", "set generic");
+    if (!FLAG_vector_ics) {
+      Code* generic = *generic_stub();
+      if (*stub == generic) {
+        TRACE_GENERIC_IC(isolate(), "KeyedLoadIC", "set generic");
+      }
+
+      set_target(*stub);
     }
-    set_target(*stub);
     TRACE_IC("LoadIC", key);
   }
 
@@ -2158,13 +2312,25 @@ RUNTIME_FUNCTION(CallIC_Customization_Miss) {
 RUNTIME_FUNCTION(LoadIC_Miss) {
   TimerEventScope<TimerEventIcMiss> timer(isolate);
   HandleScope scope(isolate);
-  DCHECK(args.length() == 2);
-  LoadIC ic(IC::NO_EXTRA_FRAME, isolate);
   Handle<Object> receiver = args.at<Object>(0);
   Handle<Name> key = args.at<Name>(1);
-  ic.UpdateState(receiver, key);
   Handle<Object> result;
-  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, ic.Load(receiver, key));
+
+  if (args.length() == 4) {
+    DCHECK(FLAG_vector_ics);

[Jakob Kummerow, 2014/11/26 15:14:14]

I think I'd swap this around:

if (FLAG_vector_ics) {
  DCHECK(args.length() == 4);

for consistency with (1) places where we DCHECK the args.length, and (2) places
where we decide how to behave based on the flag. (Also makes it more mechanical
to remove the flag some day.)

[mvstanton, 2014/11/27 13:09:26]

Cool. This is a relic of a time in the work when both types existed at once. Thk
God those days are done...fixing :).

+    Handle<Smi> slot = args.at<Smi>(2);
+    Handle<TypeFeedbackVector> vector = args.at<TypeFeedbackVector>(3);
+    FeedbackVectorICSlot vector_slot = vector->ToICSlot(slot->value());
+    LoadICNexus nexus(vector, vector_slot);
+    LoadIC ic(IC::NO_EXTRA_FRAME, isolate, &nexus);
+    ic.UpdateState(receiver, key);
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, ic.Load(receiver, key));
+  } else {
+    DCHECK(args.length() == 2);
+    LoadIC ic(IC::NO_EXTRA_FRAME, isolate);
+    ic.UpdateState(receiver, key);
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, ic.Load(receiver, key));
+  }
   return *result;
 }
 
@@ -2173,13 +2339,26 @@ RUNTIME_FUNCTION(LoadIC_Miss) {
 RUNTIME_FUNCTION(KeyedLoadIC_Miss) {
   TimerEventScope<TimerEventIcMiss> timer(isolate);
   HandleScope scope(isolate);
-  DCHECK(args.length() == 2);
-  KeyedLoadIC ic(IC::NO_EXTRA_FRAME, isolate);
   Handle<Object> receiver = args.at<Object>(0);
   Handle<Object> key = args.at<Object>(1);
-  ic.UpdateState(receiver, key);
   Handle<Object> result;
-  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, ic.Load(receiver, key));
+
+  if (args.length() == 4) {
+    DCHECK(FLAG_vector_ics);

[Jakob Kummerow, 2014/11/26 15:14:15]

again

[mvstanton, 2014/11/27 13:09:26]

Done.

+    Handle<Smi> slot = args.at<Smi>(2);
+    Handle<TypeFeedbackVector> vector = args.at<TypeFeedbackVector>(3);
+    FeedbackVectorICSlot vector_slot = vector->ToICSlot(slot->value());
+    KeyedLoadICNexus nexus(vector, vector_slot);
+    KeyedLoadIC ic(IC::NO_EXTRA_FRAME, isolate, &nexus);
+    ic.UpdateState(receiver, key);
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, ic.Load(receiver, key));
+  } else {
+    DCHECK(args.length() == 2);
+    KeyedLoadIC ic(IC::NO_EXTRA_FRAME, isolate);
+    ic.UpdateState(receiver, key);
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, ic.Load(receiver, key));
+  }
+
   return *result;
 }
 
@@ -2187,13 +2366,26 @@ RUNTIME_FUNCTION(KeyedLoadIC_Miss) {
 RUNTIME_FUNCTION(KeyedLoadIC_MissFromStubFailure) {
   TimerEventScope<TimerEventIcMiss> timer(isolate);
   HandleScope scope(isolate);
-  DCHECK(args.length() == 2);
-  KeyedLoadIC ic(IC::EXTRA_CALL_FRAME, isolate);
   Handle<Object> receiver = args.at<Object>(0);
   Handle<Object> key = args.at<Object>(1);
-  ic.UpdateState(receiver, key);
   Handle<Object> result;
-  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, ic.Load(receiver, key));
+
+  if (args.length() == 4) {
+    DCHECK(FLAG_vector_ics);

[Jakob Kummerow, 2014/11/26 15:14:14]

again

[mvstanton, 2014/11/27 13:09:26]

Done.

+    Handle<Smi> slot = args.at<Smi>(2);
+    Handle<TypeFeedbackVector> vector = args.at<TypeFeedbackVector>(3);
+    FeedbackVectorICSlot vector_slot = vector->ToICSlot(slot->value());
+    KeyedLoadICNexus nexus(vector, vector_slot);
+    KeyedLoadIC ic(IC::EXTRA_CALL_FRAME, isolate, &nexus);
+    ic.UpdateState(receiver, key);
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, ic.Load(receiver, key));
+  } else {
+    DCHECK(args.length() == 2);
+    KeyedLoadIC ic(IC::EXTRA_CALL_FRAME, isolate);
+    ic.UpdateState(receiver, key);
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, ic.Load(receiver, key));
+  }
+
   return *result;
 }
 
@@ -2685,7 +2877,7 @@ static Object* ThrowReferenceError(Isolate* isolate, Name* name) {
   // If the load is non-contextual, just return the undefined result.
   // Note that both keyed and non-keyed loads may end up here.
   HandleScope scope(isolate);
-  LoadIC ic(IC::NO_EXTRA_FRAME, isolate);
+  LoadIC ic(IC::NO_EXTRA_FRAME, isolate, true);
   if (ic.contextual_mode() != CONTEXTUAL) {
     return isolate->heap()->undefined_value();
   }
@@ -2767,13 +2959,26 @@ RUNTIME_FUNCTION(LoadElementWithInterceptor) {
 RUNTIME_FUNCTION(LoadIC_MissFromStubFailure) {
   TimerEventScope<TimerEventIcMiss> timer(isolate);
   HandleScope scope(isolate);
-  DCHECK(args.length() == 2);
-  LoadIC ic(IC::EXTRA_CALL_FRAME, isolate);
   Handle<Object> receiver = args.at<Object>(0);
   Handle<Name> key = args.at<Name>(1);
-  ic.UpdateState(receiver, key);
   Handle<Object> result;
-  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, ic.Load(receiver, key));
+
+  if (args.length() == 4) {
+    DCHECK(FLAG_vector_ics);

[Jakob Kummerow, 2014/11/26 15:14:14]

again

[mvstanton, 2014/11/27 13:09:26]

Done.

+    Handle<Smi> slot = args.at<Smi>(2);
+    Handle<TypeFeedbackVector> vector = args.at<TypeFeedbackVector>(3);
+    FeedbackVectorICSlot vector_slot = vector->ToICSlot(slot->value());
+    LoadICNexus nexus(vector, vector_slot);
+    LoadIC ic(IC::EXTRA_CALL_FRAME, isolate, &nexus);
+    ic.UpdateState(receiver, key);
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, ic.Load(receiver, key));
+  } else {
+    DCHECK(args.length() == 2);
+    LoadIC ic(IC::EXTRA_CALL_FRAME, isolate);
+    ic.UpdateState(receiver, key);
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, ic.Load(receiver, key));
+  }
+
   return *result;
 }