Move field index into property details, freeing up the value slot of fields.

BUG=
R=jkummerow@chromium.org

Review URL: https://chromiumcodereview.appspot.com/15941016

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14909 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/handles.cc

@@ -802,7 +802,7 @@ Handle<FixedArray> GetEnumPropertyKeys(Handle<JSObject> object,
           if (details.type() != FIELD) {
             indices = Handle<FixedArray>();
           } else {
-            int field_index = Descriptor::IndexFromValue(descs->GetValue(i));
+            int field_index = descs->GetFieldIndex(i);
             if (field_index >= map->inobject_properties()) {
               field_index = -(field_index - map->inobject_properties() + 1);
             }

src/json-stringifier.h

@@ -640,7 +640,7 @@ BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSObject(
       if (!name->IsString()) continue;
       Handle<String> key = Handle<String>::cast(name);
       PropertyDetails details = map->instance_descriptors()->GetDetails(i);
-      if (details.IsDontEnum() || details.IsDeleted()) continue;
+      if (details.IsDontEnum()) continue;
       Handle<Object> property;
       if (details.type() == FIELD && *map == object->map()) {
         property = Handle<Object>(

src/objects-inl.h

@@ -58,7 +58,10 @@ PropertyDetails::PropertyDetails(Smi* smi) {
 
 
 Smi* PropertyDetails::AsSmi() {
-  return Smi::FromInt(value_);
+  // Ensure the upper 2 bits have the same value by sign extending it. This is
+  // necessary to be able to use the 31st bit of the property details.
+  int value = value_ << 1;
+  return Smi::FromInt(value >> 1);
 }
 
 
@@ -2327,7 +2330,7 @@ PropertyType DescriptorArray::GetType(int descriptor_number) {
 
 
 int DescriptorArray::GetFieldIndex(int descriptor_number) {
-  return Descriptor::IndexFromValue(GetValue(descriptor_number));
+  return GetDetails(descriptor_number).field_index();
 }
 
 

src/objects.cc

@@ -2500,8 +2500,6 @@ Map* Map::FindLastMatchMap(int verbatim,
     if (details.type() != next_details.type()) break;
     if (details.attributes() != next_details.attributes()) break;
     if (!details.representation().Equals(next_details.representation())) break;
-    ASSERT(!details.IsDeleted());
-    ASSERT(!next_details.IsDeleted());
 
     current = next;
   }

src/property-details.h

@@ -169,10 +169,12 @@ class PropertyDetails BASE_EMBEDDED {
 
   PropertyDetails(PropertyAttributes attributes,
                   PropertyType type,
-                  Representation representation) {
+                  Representation representation,
+                  int field_index = 0) {
     value_ = TypeField::encode(type)
         | AttributesField::encode(attributes)
-        | RepresentationField::encode(EncodeRepresentation(representation));
+        | RepresentationField::encode(EncodeRepresentation(representation))
+        | FieldIndexField::encode(field_index);
   }
 
   int pointer() { return DescriptorPointer::decode(value_); }
@@ -214,6 +216,10 @@ class PropertyDetails BASE_EMBEDDED {
     return DecodeRepresentation(RepresentationField::decode(value_));
   }
 
+  int  field_index() {
+    return FieldIndexField::decode(value_);
+  }
+
   inline PropertyDetails AsDeleted();
 
   static bool IsValidIndex(int index) {
@@ -229,10 +235,15 @@ class PropertyDetails BASE_EMBEDDED {
   // constants can be embedded in generated code.
   class TypeField:                public BitField<PropertyType,       0,  3> {};
   class AttributesField:          public BitField<PropertyAttributes, 3,  3> {};
+
+  // Bit fields for normalized objects.
   class DeletedField:             public BitField<uint32_t,           6,  1> {};
   class DictionaryStorageField:   public BitField<uint32_t,           7, 24> {};
-  class DescriptorPointer:        public BitField<uint32_t,           7, 11> {};
-  class RepresentationField:      public BitField<uint32_t,          18,  3> {};
+
+  // Bit fields for fast objects.
+  class DescriptorPointer:        public BitField<uint32_t,           6, 11> {};
+  class RepresentationField:      public BitField<uint32_t,          17,  3> {};
+  class FieldIndexField:          public BitField<uint32_t,          20, 11> {};
 
   static const int kInitialIndex = 1;
 

src/property.h

@@ -44,10 +44,6 @@ namespace internal {
 
 class Descriptor BASE_EMBEDDED {
  public:
-  static int IndexFromValue(Object* value) {
-    return Smi::cast(value)->value();
-  }
-
   MUST_USE_RESULT MaybeObject* KeyToUniqueName() {
     if (!key_->IsUniqueName()) {
       MaybeObject* maybe_result = HEAP->InternalizeString(String::cast(key_));
@@ -89,10 +85,11 @@ class Descriptor BASE_EMBEDDED {
              Object* value,
              PropertyAttributes attributes,
              PropertyType type,
-             Representation representation)
+             Representation representation,
+             int field_index = 0)
       : key_(key),
         value_(value),
-        details_(attributes, type, representation) { }
+        details_(attributes, type, representation, field_index) { }
 
   friend class DescriptorArray;
 };
@@ -104,8 +101,8 @@ class FieldDescriptor: public Descriptor {
                   int field_index,
                   PropertyAttributes attributes,
                   Representation representation)
-      : Descriptor(key, Smi::FromInt(field_index), attributes,
-                   FIELD, representation) {}
+      : Descriptor(key, Smi::FromInt(0), attributes,
+                   FIELD, representation, field_index) {}
 };
 
 
@@ -311,7 +308,6 @@ class LookupResult BASE_EMBEDDED {
 
   bool IsDontDelete() { return details_.IsDontDelete(); }
   bool IsDontEnum() { return details_.IsDontEnum(); }
-  bool IsDeleted() { return details_.IsDeleted(); }
   bool IsFound() { return lookup_type_ != NOT_FOUND; }
   bool IsTransition() { return lookup_type_ == TRANSITION_TYPE; }
   bool IsHandler() { return lookup_type_ == HANDLER_TYPE; }
@@ -417,14 +413,12 @@ class LookupResult BASE_EMBEDDED {
   PropertyIndex GetFieldIndex() {
     ASSERT(lookup_type_ == DESCRIPTOR_TYPE);
     ASSERT(IsField());
-    return PropertyIndex::NewFieldIndex(
-        Descriptor::IndexFromValue(GetValue()));
+    return PropertyIndex::NewFieldIndex(GetFieldIndexFromMap(holder()->map()));
   }
 
   int GetLocalFieldIndexFromMap(Map* map) {
     ASSERT(IsField());
-    return Descriptor::IndexFromValue(GetValueFromMap(map)) -
-        map->inobject_properties();
+    return GetFieldIndexFromMap(map) - map->inobject_properties();
   }
 
   int GetDictionaryEntry() {
@@ -466,6 +460,12 @@ class LookupResult BASE_EMBEDDED {
     return map->instance_descriptors()->GetValue(number_);
   }
 
+  int GetFieldIndexFromMap(Map* map) const {
+    ASSERT(lookup_type_ == DESCRIPTOR_TYPE);
+    ASSERT(number_ < map->NumberOfOwnDescriptors());
+    return map->instance_descriptors()->GetFieldIndex(number_);
+  }
+
   void Iterate(ObjectVisitor* visitor);
 
  private: