Track representations of fields

src/objects.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1042 matching lines @@
   inline bool IsArgumentsMarker();
   inline bool NonFailureIsHeapObject();
 
   // Filler objects (fillers and free space objects).
   inline bool IsFiller();
 
   // Extract the number.
   inline double Number();
   inline bool IsNaN();
 
+  inline Representation OptimalRepresentation() {
+    if (FLAG_track_fields && IsSmi()) {
+      return Representation::Smi();
+    } else if (FLAG_track_double_fields && IsHeapNumber()) {
+      return Representation::Double();
+    } else {
+      return Representation::Tagged();
+    }
+  }
+
+  inline bool FitsRepresentation(Representation representation) {
+    if (FLAG_track_fields && representation.IsSmi()) {
+      return IsSmi();
+    } else if (FLAG_track_double_fields && representation.IsDouble()) {
+      return IsNumber();
+    }
+    return true;
+  }
+
   // Returns true if the object is of the correct type to be used as a
   // implementation of a JSObject's elements.
   inline bool HasValidElements();
 
   inline bool HasSpecificClassOf(String* name);
 
   MUST_USE_RESULT MaybeObject* ToObject();             // ECMA-262 9.9.
   bool BooleanValue();                                 // ECMA-262 9.2.
 
   // Convert to a JSObject if needed.
@@ skipping 726 matching lines @@
 
   // Try to follow an existing transition to a field with attributes NONE. The
   // return value indicates whether the transition was successful.
   static inline Handle<Map> FindTransitionToField(Handle<Map> map,
                                                   Handle<Name> key);
 
   inline int LastAddedFieldIndex();
 
   // Extend the receiver with a single fast property appeared first in the
   // passed map. This also extends the property backing store if necessary.
-  static void AddFastPropertyUsingMap(Handle<JSObject> object, Handle<Map> map);
-  inline MUST_USE_RESULT MaybeObject* AddFastPropertyUsingMap(Map* map);
   static void TransitionToMap(Handle<JSObject> object, Handle<Map> map);
   inline MUST_USE_RESULT MaybeObject* TransitionToMap(Map* map);
 
+  static void MigrateInstance(Handle<JSObject> instance);
+  inline MUST_USE_RESULT MaybeObject* MigrateInstance();
+
   // Can cause GC.
   MUST_USE_RESULT MaybeObject* SetLocalPropertyIgnoreAttributes(
       Name* key,
       Object* value,
       PropertyAttributes attributes);
 
   // Retrieve a value in a normalized object given a lookup result.
   // Handles the special representation of JS global objects.
   Object* GetNormalizedProperty(LookupResult* result);
 
@@ skipping 333 matching lines @@
       Object* new_value,
       PropertyAttributes attributes);
 
   // Converts a descriptor of any other type to a real field, backed by the
   // properties array.
   MUST_USE_RESULT MaybeObject* ConvertDescriptorToField(
       Name* name,
       Object* new_value,
       PropertyAttributes attributes);
 
+  MUST_USE_RESULT MaybeObject* MigrateToMap(Map* new_map);
+  MUST_USE_RESULT MaybeObject* GeneralizeFieldRepresentation(
+      int modify_index,
+      Representation new_representation);
+
   // Add a property to a fast-case object.
   MUST_USE_RESULT MaybeObject* AddFastProperty(
       Name* name,
       Object* value,
       PropertyAttributes attributes,
       StoreFromKeyed store_mode = MAY_BE_STORE_FROM_KEYED);
 
   // Add a property to a slow-case object.
   MUST_USE_RESULT MaybeObject* AddSlowProperty(Name* name,
                                                Object* value,
@@ skipping 569 matching lines @@
   inline PropertyDetails GetDetails(int descriptor_number);
   inline PropertyType GetType(int descriptor_number);
   inline int GetFieldIndex(int descriptor_number);
   inline JSFunction* GetConstantFunction(int descriptor_number);
   inline Object* GetCallbacksObject(int descriptor_number);
   inline AccessorDescriptor* GetCallbacks(int descriptor_number);
 
   inline Name* GetSortedKey(int descriptor_number);
   inline int GetSortedKeyIndex(int descriptor_number);
   inline void SetSortedKey(int pointer, int descriptor_number);
+  inline void InitializeRepresentations(Representation representation);
+  inline void SetRepresentation(int descriptor_number,
+                                Representation representation);
 
   // Accessor for complete descriptor.
   inline void Get(int descriptor_number, Descriptor* desc);
   inline void Set(int descriptor_number,
                   Descriptor* desc,
                   const WhitenessWitness&);
   inline void Set(int descriptor_number, Descriptor* desc);
 
   // Append automatically sets the enumeration index. This should only be used
   // to add descriptors in bulk at the end, followed by sorting the descriptor
   // array.
   inline void Append(Descriptor* desc, const WhitenessWitness&);
   inline void Append(Descriptor* desc);
 
   // Transfer a complete descriptor from the src descriptor array to this
   // descriptor array.
   void CopyFrom(int dst_index,
                 DescriptorArray* src,
                 int src_index,
                 const WhitenessWitness&);
+  MUST_USE_RESULT MaybeObject* Merge(int verbatim,
+                                     int valid,
+                                     int new_size,
+                                     DescriptorArray* other);
 
   MUST_USE_RESULT MaybeObject* CopyUpTo(int enumeration_index);
 
   // Sort the instance descriptors by the hash codes of their keys.
   void Sort();
 
   // Search the instance descriptors for given name.
   INLINE(int Search(Name* name, int number_of_own_descriptors));
 
   // As the above, but uses DescriptorLookupCache and updates it when
@@ skipping 2096 matching lines @@
 // All code indexes used in the class are counted starting from the first
 // code object of the first group. In other words, code index 0 corresponds
 // to array index n = kCodesStartIndex.
 
 class DependentCode: public FixedArray {
  public:
   enum DependencyGroup {
     // Group of code that weakly embed this map and depend on being
     // deoptimized when the map is garbage collected.
     kWeaklyEmbeddedGroup,
+    // Group of code that embed a transition to this map, and depend on being
+    // deoptimized when the transition is replaced by a new version.
+    kTransitionGroup,
     // Group of code that omit run-time prototype checks for prototypes
     // described by this map. The group is deoptimized whenever an object
     // described by this map changes shape (and transitions to a new map),
     // possibly invalidating the assumptions embedded in the code.
     kPrototypeCheckGroup,
     kGroupCount = kPrototypeCheckGroup + 1
   };
 
   // Array for holding the index of the first code object of each group.
   // The last element stores the total number of code objects.
@@ skipping 73 matching lines @@
   inline int bit_field3();
   inline void set_bit_field3(int value);
 
   class EnumLengthBits:             public BitField<int,   0, 11> {};
   class NumberOfOwnDescriptorsBits: public BitField<int,  11, 11> {};
   class IsShared:                   public BitField<bool, 22,  1> {};
   class FunctionWithPrototype:      public BitField<bool, 23,  1> {};
   class DictionaryMap:              public BitField<bool, 24,  1> {};
   class OwnsDescriptors:            public BitField<bool, 25,  1> {};
   class IsObserved:                 public BitField<bool, 26,  1> {};
+  class Deprecated:                 public BitField<bool, 27,  1> {};
 
   // Tells whether the object in the prototype property will be used
   // for instances created from this function.  If the prototype
   // property is set to a value that is not a JSObject, the prototype
   // property will not be used to create instances of the function.
   // See ECMA-262, 13.2.2.
   inline void set_non_instance_prototype(bool value);
   inline bool has_non_instance_prototype();
 
   // Tells whether function has special prototype property. If not, prototype
@@ skipping 122 matching lines @@
       Map* transitioned_map);
   inline void SetTransition(int transition_index, Map* target);
   inline Map* GetTransition(int transition_index);
   MUST_USE_RESULT inline MaybeObject* AddTransition(Name* key,
                                                     Map* target,
                                                     SimpleTransitionFlag flag);
   DECL_ACCESSORS(transitions, TransitionArray)
   inline void ClearTransitions(Heap* heap,
                                WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
 
+  void DeprecateTransitionTree();
+  void DeprecateTarget(Name* key, DescriptorArray* new_descriptors);
+
+  Map* FindRootMap();
+  Map* FindUpdatedMap(int verbatim, int length, DescriptorArray* descriptors);
+  Map* FindLastMatchMap(int verbatim, int length, DescriptorArray* descriptors);
+
+  int NumberOfFields();
+
+  bool InstancesNeedRewriting(int target_number_of_fields,
+                              int target_inobject,
+                              int target_unused);
+  static Handle<Map> GeneralizeRepresentation(
+      Handle<Map> map,
+      int modify_index,
+      Representation new_representation);
+  MUST_USE_RESULT MaybeObject* GeneralizeRepresentation(
+      int modify_index,
+      Representation representation);
+  MUST_USE_RESULT MaybeObject* CopyGeneralizeAllRepresentations();
+
   // Tells whether the map is attached to SharedFunctionInfo
   // (for inobject slack tracking).
   inline void set_attached_to_shared_function_info(bool value);
 
   inline bool attached_to_shared_function_info();
 
   // Tells whether the map is shared between objects that may have different
   // behavior. If true, the map should never be modified, instead a clone
   // should be created and modified.
   inline void set_is_shared(bool value);
@@ skipping 118 matching lines @@
       ASSERT(length <= NumberOfOwnDescriptors());
     }
     set_bit_field3(EnumLengthBits::update(bit_field3(), length));
   }
 
   inline bool CanTrackAllocationSite();
   inline bool owns_descriptors();
   inline void set_owns_descriptors(bool is_shared);
   inline bool is_observed();
   inline void set_is_observed(bool is_observed);
+  inline void deprecate();
+  inline bool is_deprecated();
+  inline bool CanBeDeprecated();
 
   MUST_USE_RESULT MaybeObject* RawCopy(int instance_size);
   MUST_USE_RESULT MaybeObject* CopyWithPreallocatedFieldDescriptors();
   MUST_USE_RESULT MaybeObject* CopyDropDescriptors();
   MUST_USE_RESULT MaybeObject* CopyReplaceDescriptors(
       DescriptorArray* descriptors,
       Name* name,
       TransitionFlag flag,
       int descriptor_index);
+  MUST_USE_RESULT MaybeObject* CopyInstallDescriptors(
+      int new_descriptor,
+      DescriptorArray* descriptors);
   MUST_USE_RESULT MaybeObject* ShareDescriptor(DescriptorArray* descriptors,
                                                Descriptor* descriptor);
   MUST_USE_RESULT MaybeObject* CopyAddDescriptor(Descriptor* descriptor,
                                                  TransitionFlag flag);
   MUST_USE_RESULT MaybeObject* CopyInsertDescriptor(Descriptor* descriptor,
                                                     TransitionFlag flag);
   MUST_USE_RESULT MaybeObject* CopyReplaceDescriptor(
       DescriptorArray* descriptors,
       Descriptor* descriptor,
       int index,
       TransitionFlag flag);
   MUST_USE_RESULT MaybeObject* AsElementsKind(ElementsKind kind);
   MUST_USE_RESULT MaybeObject* CopyAsElementsKind(ElementsKind kind,
                                                   TransitionFlag flag);
 
   MUST_USE_RESULT MaybeObject* CopyNormalized(PropertyNormalizationMode mode,
                                               NormalizedMapSharingMode sharing);
 
   inline void AppendDescriptor(Descriptor* desc,
                                const DescriptorArray::WhitenessWitness&);
 
   // Returns a copy of the map, with all transitions dropped from the
   // instance descriptors.
   MUST_USE_RESULT MaybeObject* Copy();
 
-  // Returns the property index for name (only valid for FAST MODE).
-  int PropertyIndexFor(Name* name);
-
   // Returns the next free property index (only valid for FAST MODE).
   int NextFreePropertyIndex();
 
   // Returns the number of properties described in instance_descriptors
   // filtering out properties with the specified attributes.
   int NumberOfDescribedProperties(DescriptorFlag which = OWN_DESCRIPTORS,
                                   PropertyAttributes filter = NONE);
 
   // Casting.
   static inline Map* cast(Object* obj);
@@ skipping 30 matching lines @@
   void RemoveFromCodeCache(Name* name, Code* code, int index);
 
   // Set all map transitions from this map to dead maps to null.  Also clear
   // back pointers in transition targets so that we do not process this map
   // again while following back pointers.
   void ClearNonLiveTransitions(Heap* heap);
 
   // Computes a hash value for this map, to be used in HashTables and such.
   int Hash();
 
+  bool EquivalentToForTransition(Map* other);
+
   // Compares this map to another to see if they describe equivalent objects.
   // If |mode| is set to CLEAR_INOBJECT_PROPERTIES, |other| is treated as if
   // it had exactly zero inobject properties.
   // The "shared" flags of both this map and |other| are ignored.
   bool EquivalentToForNormalization(Map* other, PropertyNormalizationMode mode);
 
   // Returns the map that this map transitions to if its elements_kind
   // is changed to |elements_kind|, or NULL if no such map is cached yet.
   // |safe_to_add_transitions| is set to false if adding transitions is not
   // allowed.
@@ skipping 4067 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_