Use the LookupIterator for SetElement and friends

src/elements.cc

Index: src/elements.cc
diff --git a/src/elements.cc b/src/elements.cc
index cf55a202b4689f6b57598abfd0ebef6fc6d2450f..2734823852896d9379bcd870f10c32cb263de373 100644
--- a/src/elements.cc
+++ b/src/elements.cc
@@ -618,6 +618,21 @@ class ElementsAccessorBase : public ElementsAccessor {
     }
   }
 
+  virtual Handle<Object> Set(Handle<JSObject> holder, uint32_t key,
+                             Handle<FixedArrayBase> backing_store,
+                             Handle<Object> value) final {
+    return ElementsAccessorSubclass::SetImpl(holder, key, backing_store, value);
+  }
+
+  static Handle<Object> SetImpl(Handle<JSObject> obj, uint32_t key,
+                                Handle<FixedArrayBase> backing_store,
+                                Handle<Object> value) {
+    CHECK(key <
+          ElementsAccessorSubclass::GetCapacityImpl(*obj, *backing_store));
+    return BackingStore::SetValue(
+        obj, Handle<BackingStore>::cast(backing_store), key, value);
+  }
+
   virtual PropertyAttributes GetAttributes(
       JSObject* holder, uint32_t key, FixedArrayBase* backing_store) final {
     return ElementsAccessorSubclass::GetAttributesImpl(holder, key,
@@ -1280,8 +1295,14 @@ class TypedElementsAccessor
 
   static PropertyAttributes GetAttributesImpl(JSObject* obj, uint32_t key,
                                               FixedArrayBase* backing_store) {
-    return key < AccessorClass::GetCapacityImpl(obj, backing_store) ? NONE
-                                                                    : ABSENT;
+    return key < AccessorClass::GetCapacityImpl(obj, backing_store)
+               ? DONT_DELETE
+               : ABSENT;
+  }
+
+  static PropertyDetails GetDetailsImpl(FixedArrayBase* backing_store,
+                                        uint32_t index) {
+    return PropertyDetails(DONT_DELETE, DATA, 0, PropertyCellType::kNoCell);
   }
 
   MUST_USE_RESULT static MaybeHandle<Object> SetLengthImpl(
@@ -1453,6 +1474,17 @@ class DictionaryElementsAccessor
     return isolate->factory()->the_hole_value();
   }
 
+  static Handle<Object> SetImpl(Handle<JSObject> obj, uint32_t key,
+                                Handle<FixedArrayBase> store,
+                                Handle<Object> value) {
+    Handle<SeededNumberDictionary> backing_store =
+        Handle<SeededNumberDictionary>::cast(store);
+    int entry = backing_store->FindEntry(key);
+    DCHECK_NE(SeededNumberDictionary::kNotFound, entry);
+    backing_store->ValueAtPut(entry, *value);
+    return value;
+  }
+
   static PropertyAttributes GetAttributesImpl(JSObject* obj, uint32_t key,
                                               FixedArrayBase* backing_store) {
     SeededNumberDictionary* dictionary =
@@ -1559,6 +1591,23 @@ class SloppyArgumentsElementsAccessor : public ElementsAccessorBase<
     }
   }
 
+  static Handle<Object> SetImpl(Handle<JSObject> obj, uint32_t key,
+                                Handle<FixedArrayBase> store,
+                                Handle<Object> value) {
+    Handle<FixedArray> parameter_map = Handle<FixedArray>::cast(store);
+    Object* probe = GetParameterMapArg(*parameter_map, key);
+    if (!probe->IsTheHole()) {
+      Context* context = Context::cast(parameter_map->get(0));
+      int context_index = Smi::cast(probe)->value();
+      DCHECK(!context->get(context_index)->IsTheHole());
+      context->set(context_index, *value);
+      return value;
+    }
+    Handle<FixedArray> arguments(FixedArray::cast(parameter_map->get(1)));
+    return ElementsAccessor::ForArray(arguments)
+        ->Set(obj, key, arguments, value);
+  }
+
   static PropertyAttributes GetAttributesImpl(JSObject* obj, uint32_t key,
                                               FixedArrayBase* backing_store) {
     FixedArray* parameter_map = FixedArray::cast(backing_store);