[runtime] Better encapsulation of dictionary objects handling in lookup iterator.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 5dc18607b2b9431a96dd50693f00d35837a27af3..4c3e47db97894811792337eb0eba7f3976f1e84f 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -2479,12 +2479,6 @@ class JSObject: public JSReceiver {
   MUST_USE_RESULT static Maybe<bool> SetPropertyWithFailedAccessCheck(
       LookupIterator* it, Handle<Object> value, ShouldThrow should_throw);
 
-  // Add a property to a slow-case object.
-  static void AddSlowProperty(Handle<JSObject> object,
-                              Handle<Name> name,
-                              Handle<Object> value,
-                              PropertyAttributes attributes);
-
   MUST_USE_RESULT static Maybe<bool> DeletePropertyWithInterceptor(
       LookupIterator* it, ShouldThrow should_throw);
 
@@ -3514,11 +3508,10 @@ class Dictionary: public HashTable<Derived, Shape, Key> {
                        Handle<Object> value,
                        PropertyDetails details);
 
-  MUST_USE_RESULT static Handle<Derived> Add(
-      Handle<Derived> dictionary,
-      Key key,
-      Handle<Object> value,
-      PropertyDetails details);
+  MUST_USE_RESULT static Handle<Derived> Add(Handle<Derived> dictionary,
+                                             Key key, Handle<Object> value,
+                                             PropertyDetails details,
+                                             int* entry_out = nullptr);
 
   // Returns iteration indices array for the |dictionary|.
   // Values are direct indices in the |HashTable| array.
@@ -3532,13 +3525,9 @@ class Dictionary: public HashTable<Derived, Shape, Key> {
       Key key,
       Handle<Object> value);
 
-  // Add entry to dictionary.
-  static void AddEntry(
-      Handle<Derived> dictionary,
-      Key key,
-      Handle<Object> value,
-      PropertyDetails details,
-      uint32_t hash);
+  // Add entry to dictionary. Returns entry value.
+  static int AddEntry(Handle<Derived> dictionary, Key key, Handle<Object> value,
+                      PropertyDetails details, uint32_t hash);
 
   // Generate new enumeration indices to avoid enumeration index overflow.
   // Returns iteration indices array for the |dictionary|.
@@ -7829,8 +7818,9 @@ class JSGlobalObject : public JSObject {
   static void InvalidatePropertyCell(Handle<JSGlobalObject> object,
                                      Handle<Name> name);
   // Ensure that the global object has a cell for the given property name.
-  static Handle<PropertyCell> EnsurePropertyCell(Handle<JSGlobalObject> global,
-                                                 Handle<Name> name);
+  static Handle<PropertyCell> EnsureEmptyPropertyCell(
+      Handle<JSGlobalObject> global, Handle<Name> name,
+      PropertyCellType cell_type, int* entry_out = nullptr);
 
   DECLARE_CAST(JSGlobalObject)
 
@@ -9680,8 +9670,12 @@ class PropertyCell : public HeapObject {
   static PropertyCellType UpdatedType(Handle<PropertyCell> cell,
                                       Handle<Object> value,
                                       PropertyDetails details);
-  static void UpdateCell(Handle<GlobalDictionary> dictionary, int entry,
-                         Handle<Object> value, PropertyDetails details);
+  // Prepares property cell at given entry for receiving given value.
+  // As a result the old cell could be invalidated and/or dependent code could
+  // be deoptimized. Returns the prepared property cell.
+  static Handle<PropertyCell> PrepareForValue(
+      Handle<GlobalDictionary> dictionary, int entry, Handle<Object> value,
+      PropertyDetails details);
 
   static Handle<PropertyCell> InvalidateEntry(
       Handle<GlobalDictionary> dictionary, int entry);