JSObject::GetEnumProperty cleanup

src/objects.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <sstream>
 
@@ skipping 6594 matching lines @@
   DCHECK(array->length() >= length);
   if (array->length() == length) return array;
 
   Handle<FixedArray> new_array =
       array->GetIsolate()->factory()->NewFixedArray(length);
   for (int i = 0; i < length; ++i) new_array->set(i, array->get(i));
   return new_array;
 }
 
 
+namespace {
+
+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 (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_enum_length) map->SetEnumLength(own_property_count);
+      return ReduceFixedArrayTo(keys, own_property_count);
+    }
+  }
+
+  if (descs->IsEmpty()) {
+    isolate->counters()->enum_cache_hits()->Increment();
+    if (cache_enum_length) map->SetEnumLength(0);
+    return isolate->factory()->empty_fixed_array();
+  }
+
+  isolate->counters()->enum_cache_misses()->Increment();
+
+  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;
+
+  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));
+      }
+    }
+    index++;
+  }
+  DCHECK(index == storage->length());
+
+  DescriptorArray::SetEnumCache(descs, isolate, storage, indices);
+  if (cache_enum_length) {
+    map->SetEnumLength(own_property_count);
+  }
+  return storage;
+}
+
+}  // namespace
+
+
 Handle<FixedArray> JSObject::GetEnumPropertyKeys(Handle<JSObject> object,
-                                                 bool cache_result) {
+                                                 bool cache_enum_length) {
   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);
-      }
-    }
-
-    Handle<Map> map(object->map());
-
-    if (map->instance_descriptors()->IsEmpty()) {
-      isolate->counters()->enum_cache_hits()->Increment();
-      if (cache_result) map->SetEnumLength(0);
-      return isolate->factory()->empty_fixed_array();
-    }
-
-    isolate->counters()->enum_cache_misses()->Increment();
-
-    Handle<FixedArray> storage = isolate->factory()->NewFixedArray(
-        own_property_count);
-    Handle<FixedArray> indices = isolate->factory()->NewFixedArray(
-        own_property_count);
-
-    Handle<DescriptorArray> descs =
-        Handle<DescriptorArray>(object->map()->instance_descriptors(), isolate);
-
-    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++;
-      }
-    }
-    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;
+    return GetFastEnumPropertyKeys(isolate, object, cache_enum_length);
   } else if (object->IsGlobalObject()) {
     Handle<GlobalDictionary> dictionary(object->global_dictionary());
     int length = dictionary->NumberOfEnumElements();
     if (length == 0) {
       return Handle<FixedArray>(isolate->heap()->empty_fixed_array());
     }
     Handle<FixedArray> storage = isolate->factory()->NewFixedArray(length);
     dictionary->CopyEnumKeysTo(*storage);
     return storage;
   } else {
@@ skipping 183 matching lines @@
     // We can cache the computed property keys if access checks are
     // not needed and no interceptors are involved.
     //
     // We do not use the cache if the object has elements and
     // therefore it does not make sense to cache the property names
     // for arguments objects.  Arguments objects will always have
     // elements.
     // 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()));
 
     // Add the non-symbol property keys from the interceptor.
     if (current->HasNamedInterceptor()) {
       Handle<JSObject> result;
       if (JSObject::GetKeysForNamedInterceptor(
               current, object).ToHandle(&result)) {
         accumulator.AddKeys(result, FixedArray::NON_SYMBOL_KEYS);
       }
@@ skipping 1732 matching lines @@
   set(kEnumCacheIndex, Smi::FromInt(0));
 }
 
 
 void DescriptorArray::Replace(int index, Descriptor* descriptor) {
   descriptor->SetSortedKeyIndex(GetSortedKeyIndex(index));
   Set(index, 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());
-  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);
+// static
+void DescriptorArray::SetEnumCache(Handle<DescriptorArray> descriptors,
+                                   Isolate* isolate,
+                                   Handle<FixedArray> new_cache,
+                                   Handle<FixedArray> new_index_cache) {
+  DCHECK(!descriptors->IsEmpty());
+  FixedArray* bridge_storage;
+  bool needs_new_enum_cache = !descriptors->HasEnumCache();
+  if (needs_new_enum_cache) {
+    bridge_storage = *isolate->factory()->NewFixedArray(
+        DescriptorArray::kEnumCacheBridgeLength);
+  } else {
+    bridge_storage = FixedArray::cast(descriptors->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) {
+    descriptors->set(kEnumCacheIndex, bridge_storage);
+  }
 }
 
 
 void DescriptorArray::CopyFrom(int index, DescriptorArray* src,
                                const WhitenessWitness& witness) {
   Object* value = src->GetValue(index);
   PropertyDetails details = src->GetDetails(index);
   Descriptor desc(handle(src->GetKey(index)),
                   handle(value, src->GetIsolate()),
                   details);
@@ skipping 8103 matching lines @@
   if (cell->value() != *new_value) {
     cell->set_value(*new_value);
     Isolate* isolate = cell->GetIsolate();
     cell->dependent_code()->DeoptimizeDependentCodeGroup(
         isolate, DependentCode::kPropertyCellChangedGroup);
   }
 }
 
 }  // namespace internal
 }  // namespace v8