[runtime] Refactor dictionary mode checks

Check the receiver_map for the dictionary mode bit instead of
comparing the properties map against the HashTableMap.

Bug: 
Change-Id: Iebf3118f00fd0afc8f7f13e88f373282c099f682
Reviewed-on: https://chromium-review.googlesource.com/578324
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46775}

src/builtins/builtins-internal-gen.cc

@@ -245,16 +245,15 @@ TF_BUILTIN(DeleteProperty, DeletePropertyBaseAssembler) {
     CheckForAssociatedProtector(unique, &slow);
 
     Label dictionary(this), dont_delete(this);
-    Node* properties = LoadProperties(receiver);
-    Node* properties_map = LoadMap(properties);
-    GotoIf(WordEqual(properties_map, LoadRoot(Heap::kHashTableMapRootIndex)),
-           &dictionary);
+    GotoIf(IsDictionaryMap(receiver_map), &dictionary);
+
     // Fast properties need to clear recorded slots, which can only be done
     // in C++.
     Goto(&slow);
 
     BIND(&dictionary);
     {
+      Node* properties = LoadProperties(receiver);
       DeleteDictionaryProperty(receiver, properties, unique, context,
                                &dont_delete, &if_notfound);
     }

src/ic/accessor-assembler.cc

@@ -1482,14 +1482,11 @@ void AccessorAssembler::GenericPropertyLoad(Node* receiver, Node* receiver_map,
          slow);
 
   // Check if the receiver has fast or slow properties.
-  Node* properties = LoadProperties(receiver);
-  Node* properties_map = LoadMap(properties);
-  GotoIf(WordEqual(properties_map, LoadRoot(Heap::kHashTableMapRootIndex)),
-         &if_property_dictionary);
+  Node* bitfield3 = LoadMapBitField3(receiver_map);
+  GotoIf(IsSetWord32<Map::DictionaryMap>(bitfield3), &if_property_dictionary);
 
   // Try looking up the property on the receiver; if unsuccessful, look
   // for a handler in the stub cache.
-  Node* bitfield3 = LoadMapBitField3(receiver_map);
   Node* descriptors = LoadMapDescriptors(receiver_map);
 
   Label if_descriptor_found(this), stub_cache(this);
@@ -1538,6 +1535,7 @@ void AccessorAssembler::GenericPropertyLoad(Node* receiver, Node* receiver_map,
 
     VARIABLE(var_name_index, MachineType::PointerRepresentation());
     Label dictionary_found(this, &var_name_index);
+    Node* properties = LoadProperties(receiver);
     NameDictionaryLookup<NameDictionary>(properties, p->name, &dictionary_found,
                                          &var_name_index,
                                          &lookup_prototype_chain);

src/ic/keyed-store-generic.cc

@@ -753,15 +753,13 @@ void KeyedStoreGenericAssembler::EmitGenericPropertyStore(
   VARIABLE(var_accessor_holder, MachineRepresentation::kTagged);
   Label stub_cache(this), fast_properties(this), dictionary_properties(this),
       accessor(this), readonly(this);
-  Node* properties = LoadProperties(receiver);
-  Node* properties_map = LoadMap(properties);
-  Branch(WordEqual(properties_map, LoadRoot(Heap::kHashTableMapRootIndex)),
-         &dictionary_properties, &fast_properties);
+  Node* bitfield3 = LoadMapBitField3(receiver_map);
+  Branch(IsSetWord32<Map::DictionaryMap>(bitfield3), &dictionary_properties,
+         &fast_properties);
 
   BIND(&fast_properties);
   {
     Comment("fast property store");
-    Node* bitfield3 = LoadMapBitField3(receiver_map);
     Node* descriptors = LoadMapDescriptors(receiver_map);
     Label descriptor_found(this);
     VARIABLE(var_name_index, MachineType::PointerRepresentation());
@@ -789,6 +787,7 @@ void KeyedStoreGenericAssembler::EmitGenericPropertyStore(
       BIND(&data_property);
       {
         CheckForAssociatedProtector(p->name, slow);
+        Node* properties = LoadProperties(receiver);
         OverwriteExistingFastProperty(receiver, receiver_map, properties,
                                       descriptors, name_index, details,
                                       p->value, slow);
@@ -805,6 +804,7 @@ void KeyedStoreGenericAssembler::EmitGenericPropertyStore(
 
     VARIABLE(var_name_index, MachineType::PointerRepresentation());
     Label dictionary_found(this, &var_name_index), not_found(this);
+    Node* properties = LoadProperties(receiver);
     NameDictionaryLookup<NameDictionary>(properties, p->name, &dictionary_found,
                                          &var_name_index, &not_found);
     BIND(&dictionary_found);