JSObject::GetEnumProperty cleanup

BUG=

Review URL: https://codereview.chromium.org/1363293002

Cr-Commit-Position: refs/heads/master@{#30946}

src/field-index-inl.h

@@ -89,8 +89,7 @@ inline int FieldIndex::GetLoadByFieldIndex() const {
 inline FieldIndex FieldIndex::ForDescriptor(Map* map, int descriptor_index) {
   PropertyDetails details =
       map->instance_descriptors()->GetDetails(descriptor_index);
-  int field_index =
-      map->instance_descriptors()->GetFieldIndex(descriptor_index);
+  int field_index = details.field_index();
   return ForPropertyIndex(map, field_index,
                           details.representation().IsDouble());
 }

src/objects.cc

@@ -6568,91 +6568,90 @@ static Handle<FixedArray> ReduceFixedArrayTo(
 }
 
 
-Handle<FixedArray> JSObject::GetEnumPropertyKeys(Handle<JSObject> object,
-                                                 bool cache_result) {
-  Isolate* isolate = object->GetIsolate();
-  if (object->HasFastProperties()) {
-    int own_property_count = object->map()->EnumLength();
-    // If the enum length of the given map is set to kInvalidEnumCache, this
-    // means that the map itself has never used the present enum cache. The
-    // first step to using the cache is to set the enum length of the map by
-    // counting the number of own descriptors that are not DONT_ENUM or
-    // SYMBOLIC.
-    if (own_property_count == kInvalidEnumCacheSentinel) {
-      own_property_count = object->map()->NumberOfDescribedProperties(
-          OWN_DESCRIPTORS, DONT_SHOW);
-    } else {
-      DCHECK(own_property_count == object->map()->NumberOfDescribedProperties(
-          OWN_DESCRIPTORS, DONT_SHOW));
-    }
-
-    if (object->map()->instance_descriptors()->HasEnumCache()) {
-      DescriptorArray* desc = object->map()->instance_descriptors();
-      Handle<FixedArray> keys(desc->GetEnumCache(), isolate);
-
-      // In case the number of properties required in the enum are actually
-      // present, we can reuse the enum cache. Otherwise, this means that the
-      // enum cache was generated for a previous (smaller) version of the
-      // Descriptor Array. In that case we regenerate the enum cache.
-      if (own_property_count <= keys->length()) {
-        if (cache_result) object->map()->SetEnumLength(own_property_count);
-        isolate->counters()->enum_cache_hits()->Increment();
-        return ReduceFixedArrayTo(keys, own_property_count);
-      }
-    }
+namespace {
 
-    Handle<Map> map(object->map());
+Handle<FixedArray> GetFastEnumPropertyKeys(Isolate* isolate,
+                                           Handle<JSObject> object,
+                                           bool cache_enum_length) {
+  Handle<Map> map(object->map());
+  Handle<DescriptorArray> descs =
+      Handle<DescriptorArray>(map->instance_descriptors(), isolate);
+  int own_property_count = map->EnumLength();
+  // If the enum length of the given map is set to kInvalidEnumCache, this
+  // means that the map itself has never used the present enum cache. The
+  // first step to using the cache is to set the enum length of the map by
+  // counting the number of own descriptors that are not DONT_ENUM or
+  // SYMBOLIC.
+  if (own_property_count == kInvalidEnumCacheSentinel) {
+    own_property_count =
+        map->NumberOfDescribedProperties(OWN_DESCRIPTORS, DONT_SHOW);
+  } else {
+    DCHECK(own_property_count ==
+           map->NumberOfDescribedProperties(OWN_DESCRIPTORS, DONT_SHOW));
+  }
 
-    if (map->instance_descriptors()->IsEmpty()) {
+  if (descs->HasEnumCache()) {
+    Handle<FixedArray> keys(descs->GetEnumCache(), isolate);
+    // In case the number of properties required in the enum are actually
+    // present, we can reuse the enum cache. Otherwise, this means that the
+    // enum cache was generated for a previous (smaller) version of the
+    // Descriptor Array. In that case we regenerate the enum cache.
+    if (own_property_count <= keys->length()) {
       isolate->counters()->enum_cache_hits()->Increment();
-      if (cache_result) map->SetEnumLength(0);
-      return isolate->factory()->empty_fixed_array();
+      if (cache_enum_length) map->SetEnumLength(own_property_count);
+      return ReduceFixedArrayTo(keys, own_property_count);
     }
+  }
 
-    isolate->counters()->enum_cache_misses()->Increment();
+  if (descs->IsEmpty()) {
+    isolate->counters()->enum_cache_hits()->Increment();
+    if (cache_enum_length) map->SetEnumLength(0);
+    return isolate->factory()->empty_fixed_array();
+  }
 
-    Handle<FixedArray> storage = isolate->factory()->NewFixedArray(
-        own_property_count);
-    Handle<FixedArray> indices = isolate->factory()->NewFixedArray(
-        own_property_count);
+  isolate->counters()->enum_cache_misses()->Increment();
 
-    Handle<DescriptorArray> descs =
-        Handle<DescriptorArray>(object->map()->instance_descriptors(), isolate);
+  Handle<FixedArray> storage =
+      isolate->factory()->NewFixedArray(own_property_count);
+  Handle<FixedArray> indices =
+      isolate->factory()->NewFixedArray(own_property_count);
 
-    int size = map->NumberOfOwnDescriptors();
-    int index = 0;
+  int size = map->NumberOfOwnDescriptors();
+  int index = 0;
 
-    for (int i = 0; i < size; i++) {
-      PropertyDetails details = descs->GetDetails(i);
-      Object* key = descs->GetKey(i);
-      if (!(details.IsDontEnum() || key->IsSymbol())) {
-        storage->set(index, key);
-        if (!indices.is_null()) {
-          if (details.type() != DATA) {
-            indices = Handle<FixedArray>();
-          } else {
-            FieldIndex field_index = FieldIndex::ForDescriptor(*map, i);
-            int load_by_field_index = field_index.GetLoadByFieldIndex();
-            indices->set(index, Smi::FromInt(load_by_field_index));
-          }
-        }
-        index++;
+  for (int i = 0; i < size; i++) {
+    PropertyDetails details = descs->GetDetails(i);
+    Object* key = descs->GetKey(i);
+    if (details.IsDontEnum() || key->IsSymbol()) continue;
+    storage->set(index, key);
+    if (!indices.is_null()) {
+      if (details.type() != DATA) {
+        indices = Handle<FixedArray>();
+      } else {
+        FieldIndex field_index = FieldIndex::ForDescriptor(*map, i);
+        int load_by_field_index = field_index.GetLoadByFieldIndex();
+        indices->set(index, Smi::FromInt(load_by_field_index));
       }
     }
-    DCHECK(index == storage->length());
+    index++;
+  }
+  DCHECK(index == storage->length());
 
-    Handle<FixedArray> bridge_storage =
-        isolate->factory()->NewFixedArray(
-            DescriptorArray::kEnumCacheBridgeLength);
-    DescriptorArray* desc = object->map()->instance_descriptors();
-    desc->SetEnumCache(*bridge_storage,
-                       *storage,
-                       indices.is_null() ? Object::cast(Smi::FromInt(0))
-                                         : Object::cast(*indices));
-    if (cache_result) {
-      object->map()->SetEnumLength(own_property_count);
-    }
-    return storage;
+  descs->SetEnumCache(isolate, storage, indices);
+  if (cache_enum_length) {
+    map->SetEnumLength(own_property_count);
+  }
+  return storage;
+}
+
+}  // namespace
+
+
+Handle<FixedArray> JSObject::GetEnumPropertyKeys(Handle<JSObject> object,
+                                                 bool cache_enum_length) {
+  Isolate* isolate = object->GetIsolate();
+  if (object->HasFastProperties()) {
+    return GetFastEnumPropertyKeys(isolate, object, cache_enum_length);
   } else if (object->IsGlobalObject()) {
     Handle<GlobalDictionary> dictionary(object->global_dictionary());
     int length = dictionary->NumberOfEnumElements();
@@ -6856,14 +6855,14 @@ MaybeHandle<FixedArray> JSReceiver::GetKeys(Handle<JSReceiver> object,
     // Wrapped strings have elements, but don't have an elements
     // array or dictionary.  So the fast inline test for whether to
     // use the cache says yes, so we should not create a cache.
-    bool cache_enum_keys =
+    bool cache_enum_length =
         ((current->map()->GetConstructor() != *arguments_function) &&
          !current->IsJSValue() && !current->IsAccessCheckNeeded() &&
          !current->HasNamedInterceptor() && !current->HasIndexedInterceptor());
     // Compute the property keys and cache them if possible.
 
     Handle<FixedArray> enum_keys =
-        JSObject::GetEnumPropertyKeys(current, cache_enum_keys);
+        JSObject::GetEnumPropertyKeys(current, cache_enum_length);
     accumulator.AddKeys(enum_keys, FixedArray::ALL_KEYS);
     DCHECK(ContainsOnlyValidKeys(accumulator.GetKeys()));
 
@@ -8616,18 +8615,25 @@ void DescriptorArray::Replace(int index, Descriptor* descriptor) {
 }
 
 
-void DescriptorArray::SetEnumCache(FixedArray* bridge_storage,
-                                   FixedArray* new_cache,
-                                   Object* new_index_cache) {
-  DCHECK(bridge_storage->length() >= kEnumCacheBridgeLength);
-  DCHECK(new_index_cache->IsSmi() || new_index_cache->IsFixedArray());
+void DescriptorArray::SetEnumCache(Isolate* isolate,
+                                   Handle<FixedArray> new_cache,
+                                   Handle<FixedArray> new_index_cache) {
   DCHECK(!IsEmpty());
-  DCHECK(!HasEnumCache() || new_cache->length() > GetEnumCache()->length());
-  FixedArray::cast(bridge_storage)->
-    set(kEnumCacheBridgeCacheIndex, new_cache);
-  FixedArray::cast(bridge_storage)->
-    set(kEnumCacheBridgeIndicesCacheIndex, new_index_cache);
-  set(kEnumCacheIndex, bridge_storage);
+  FixedArray* bridge_storage;
+  bool needs_new_enum_cache = !HasEnumCache();
+  if (needs_new_enum_cache) {
+    bridge_storage = *isolate->factory()->NewFixedArray(
+        DescriptorArray::kEnumCacheBridgeLength);
+  } else {
+    bridge_storage = FixedArray::cast(get(kEnumCacheIndex));
+  }
+  bridge_storage->set(kEnumCacheBridgeCacheIndex, *new_cache);
+  bridge_storage->set(kEnumCacheBridgeIndicesCacheIndex,
+                      new_index_cache.is_null() ? Object::cast(Smi::FromInt(0))
+                                                : *new_index_cache);
+  if (needs_new_enum_cache) {
+    set(kEnumCacheIndex, bridge_storage);
+  }
 }
 
 

src/objects.h

@@ -2745,9 +2745,8 @@ class DescriptorArray: public FixedArray {
 
   // Initialize or change the enum cache,
   // using the supplied storage for the small "bridge".
-  void SetEnumCache(FixedArray* bridge_storage,
-                    FixedArray* new_cache,
-                    Object* new_index_cache);
+  void SetEnumCache(Isolate* isolate, Handle<FixedArray> new_cache,
+                    Handle<FixedArray> new_index_cache);
 
   bool CanHoldValue(int descriptor, Object* value);