Revert "In-object double fields unboxing (for 64-bit only)."

src/layout-descriptor.h

-// Copyright 2014 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.
-
-#ifndef V8_LAYOUT_DESCRIPTOR_H_
-#define V8_LAYOUT_DESCRIPTOR_H_
-
-#include <iosfwd>
-
-#include "src/objects.h"
-
-namespace v8 {
-namespace internal {
-
-// LayoutDescriptor is a bit vector defining which fields contain non-tagged
-// values. It could either be a fixed typed array (slow form) or a Smi
-// if the length fits (fast form).
-// Each bit in the layout represents a FIELD. The bits are referenced by
-// field_index which is a field number. If the bit is set then the corresponding
-// field contains a non-tagged value and therefore must be skipped by GC.
-// Otherwise the field is considered tagged. If the queried bit lays "outside"
-// of the descriptor then the field is also considered tagged.
-// Once a layout descriptor is created it is allowed only to append properties
-// to it.
-class LayoutDescriptor : public FixedTypedArray<Uint32ArrayTraits> {
- public:
-  V8_INLINE bool IsTagged(int field_index);
-
-  // Returns true if this is a layout of the object having only tagged fields.
-  V8_INLINE bool IsFastPointerLayout();
-
-  // Returns true if the layout descriptor is in non-Smi form.
-  V8_INLINE bool IsSlowLayout();
-
-  V8_INLINE static LayoutDescriptor* cast(Object* object);
-  V8_INLINE static const LayoutDescriptor* cast(const Object* object);
-
-  V8_INLINE static LayoutDescriptor* cast_gc_safe(Object* object);
-
-  // Builds layout descriptor optimized for given |map| by |num_descriptors|
-  // elements of given descriptors array. The |map|'s descriptors could be
-  // different.
-  static Handle<LayoutDescriptor> New(Handle<Map> map,
-                                      Handle<DescriptorArray> descriptors,
-                                      int num_descriptors);
-
-  // Creates new layout descriptor by appending property with |details| to
-  // |map|'s layout descriptor.
-  static Handle<LayoutDescriptor> Append(Handle<Map> map,
-                                         PropertyDetails details);
-
-  // Creates new layout descriptor by appending property with |details| to
-  // |map|'s layout descriptor and if it is still fast then returns it.
-  // Otherwise the |full_layout_descriptor| is returned.
-  static Handle<LayoutDescriptor> AppendIfFastOrUseFull(
-      Handle<Map> map, PropertyDetails details,
-      Handle<LayoutDescriptor> full_layout_descriptor);
-
-  // Layout descriptor that corresponds to an object all fields of which are
-  // tagged (FastPointerLayout).
-  V8_INLINE static LayoutDescriptor* FastPointerLayout();
-
-#ifdef DEBUG
-  // Check that this layout descriptor corresponds to given map.
-  bool IsConsistentWithMap(Map* map);
-#endif
-
-#ifdef OBJECT_PRINT
-  // For our gdb macros, we should perhaps change these in the future.
-  void Print();
-
-  void Print(std::ostream& os);  // NOLINT
-#endif
-
-  // Capacity of layout descriptors in bits.
-  V8_INLINE int capacity();
-
-  V8_INLINE LayoutDescriptor* SetTaggedForTesting(int field_index,
-                                                  bool tagged) {
-    return SetTagged(field_index, tagged);
-  }
-
- private:
-  static const int kNumberOfBits = 32;
-
-  V8_INLINE static Handle<LayoutDescriptor> New(Isolate* isolate, int length);
-  V8_INLINE static LayoutDescriptor* FromSmi(Smi* smi);
-
-  V8_INLINE static bool InobjectUnboxedField(int inobject_properties,
-                                             PropertyDetails details);
-
-  static Handle<LayoutDescriptor> EnsureCapacity(
-      Isolate* isolate, Handle<LayoutDescriptor> layout_descriptor,
-      int new_capacity);
-
-  // Returns false if requested field_index is out of bounds.
-  V8_INLINE bool GetIndexes(int field_index, int* layout_word_index,
-                            uint32_t* layout_mask);
-
-  V8_INLINE MUST_USE_RESULT LayoutDescriptor* SetRawData(int field_index) {
-    return SetTagged(field_index, false);
-  }
-
-  V8_INLINE MUST_USE_RESULT LayoutDescriptor* SetTagged(int field_index,
-                                                        bool tagged);
-};
-
-
-// InobjectPropertiesHelper is a helper class for querying layout descriptor
-// about whether the field at given offset is tagged or not.
-class InobjectPropertiesHelper {
- public:
-  inline explicit InobjectPropertiesHelper(Map* map);
-
-  bool all_fields_tagged() { return all_fields_tagged_; }
-  inline bool IsTagged(int offset_in_bytes);
-
- private:
-  bool all_fields_tagged_;
-  int header_size_;
-  LayoutDescriptor* layout_descriptor_;
-};
-}
-}  // namespace v8::internal
-
-#endif  // V8_LAYOUT_DESCRIPTOR_H_