Add monomorphic CompareNilICs and Crankshaft support

src/type-info.cc

Index: src/type-info.cc
diff --git a/src/type-info.cc b/src/type-info.cc
index 39a01f59e8d826c41f027133af064d8289a4ca55..3bc509a6189a93068ee2f50b6f0a90d9aeffef67 100644
--- a/src/type-info.cc
+++ b/src/type-info.cc
@@ -218,6 +218,17 @@ Handle<Map> TypeFeedbackOracle::StoreMonomorphicReceiverType(
 }
 
 
+Handle<Map> TypeFeedbackOracle::CompareNilMonomorphicReceiverType(
+    TypeFeedbackId id) {
+  Handle<Object> maybe_code = GetInfo(id);
+  if (maybe_code->IsCode()) {
+    Map* first_map = Handle<Code>::cast(maybe_code)->FindFirstMap();
+    if (first_map != NULL) return Handle<Map>(first_map);
+  }
+  return Handle<Map>();
+}
+
+
 KeyedAccessStoreMode TypeFeedbackOracle::GetStoreMode(
     TypeFeedbackId ast_id) {
   Handle<Object> map_or_code = GetInfo(ast_id);
@@ -625,12 +636,23 @@ void TypeFeedbackOracle::CollectKeyedReceiverTypes(TypeFeedbackId ast_id,
 }
 
 
-byte TypeFeedbackOracle::ToBooleanTypes(TypeFeedbackId ast_id) {
-  Handle<Object> object = GetInfo(ast_id);
+byte TypeFeedbackOracle::ToBooleanTypes(TypeFeedbackId id) {
+  Handle<Object> object = GetInfo(id);
   return object->IsCode() ? Handle<Code>::cast(object)->to_boolean_state() : 0;
 }
 
 
+byte TypeFeedbackOracle::CompareNilTypes(TypeFeedbackId id) {
+  Handle<Object> object = GetInfo(id);
+  if (object->IsCode() &&
+      Handle<Code>::cast(object)->is_compare_nil_ic_stub()) {
+    return Handle<Code>::cast(object)->compare_nil_state();
+  } else {
+    return CompareNilICStub::kFullCompare;
+  }
+}
+
+
 // Things are a bit tricky here: The iterator for the RelocInfos and the infos
 // themselves are not GC-safe, so we first get all infos, then we create the
 // dictionary (possibly triggering GC), and finally we relocate the collected
@@ -724,6 +746,7 @@ void TypeFeedbackOracle::ProcessRelocInfos(ZoneList<RelocInfo>* infos) {
       case Code::BINARY_OP_IC:
       case Code::COMPARE_IC:
       case Code::TO_BOOLEAN_IC:
+      case Code::COMPARE_NIL_IC:
         SetInfo(ast_id, target);
         break;