Line data    Source code

       1             : // Copyright 2014 the V8 project authors. All rights reserved.
       2             : // Use of this source code is governed by a BSD-style license that can be
       3             : // found in the LICENSE file.
       4             : 
       5             : #ifndef V8_FIELD_INDEX_H_
       6             : #define V8_FIELD_INDEX_H_
       7             : 
       8             : #include "src/property-details.h"
       9             : #include "src/utils.h"
      10             : 
      11             : namespace v8 {
      12             : namespace internal {
      13             : 
      14             : class Map;
      15             : 
      16             : // Wrapper class to hold a field index, usually but not necessarily generated
      17             : // from a property index. When available, the wrapper class captures additional
      18             : // information to allow the field index to be translated back into the property
      19             : // index it was originally generated from.
      20             : class FieldIndex final {
      21             :  public:
      22      158510 :   FieldIndex() : bit_field_(0) {}
      23             : 
      24             :   static FieldIndex ForPropertyIndex(Map* map,
      25             :                                      int index,
      26             :                                      bool is_double = false);
      27             :   static FieldIndex ForInObjectOffset(int offset, Map* map = NULL);
      28             :   static FieldIndex ForDescriptor(Map* map, int descriptor_index);
      29             :   static FieldIndex ForLoadByFieldIndex(Map* map, int index);
      30             :   static FieldIndex FromFieldAccessStubKey(int key);
      31             : 
      32             :   int GetLoadByFieldIndex() const;
      33             : 
      34          14 :   bool is_inobject() const {
      35   279158509 :     return IsInObjectBits::decode(bit_field_);
      36             :   }
      37             : 
      38   194021000 :   bool is_hidden_field() const { return IsHiddenField::decode(bit_field_); }
      39             : 
      40             :   bool is_double() const {
      41          28 :     return IsDoubleBits::decode(bit_field_);
      42             :   }
      43             : 
      44             :   int offset() const {
      45   174866237 :     return index() * kPointerSize;
      46             :   }
      47             : 
      48             :   // Zero-indexed from beginning of the object.
      49             :   int index() const {
      50      620146 :     return IndexBits::decode(bit_field_);
      51             :   }
      52             : 
      53           0 :   int outobject_array_index() const {
      54             :     DCHECK(!is_inobject());
      55   103538881 :     return index() - first_inobject_property_offset() / kPointerSize;
      56             :   }
      57             : 
      58             :   // Zero-based from the first inobject property. Overflows to out-of-object
      59             :   // properties.
      60          14 :   int property_index() const {
      61             :     DCHECK(!is_hidden_field());
      62   117112550 :     int result = index() - first_inobject_property_offset() / kPointerSize;
      63   117112550 :     if (!is_inobject()) {
      64           0 :       result += InObjectPropertyBits::decode(bit_field_);
      65             :     }
      66          14 :     return result;
      67             :   }
      68             : 
      69             :   int GetFieldAccessStubKey() const {
      70             :     return bit_field_ &
      71             :         (IsInObjectBits::kMask | IsDoubleBits::kMask | IndexBits::kMask);
      72             :   }
      73             : 
      74             :   bool operator==(FieldIndex const& other) const {
      75        4759 :     return bit_field_ == other.bit_field_;
      76             :   }
      77             :   bool operator!=(FieldIndex const& other) const { return !(*this == other); }
      78             : 
      79             :  private:
      80             :   FieldIndex(bool is_inobject, int local_index, bool is_double,
      81             :              int inobject_properties, int first_inobject_property_offset,
      82             :              bool is_hidden = false) {
      83             :     DCHECK((first_inobject_property_offset & (kPointerSize - 1)) == 0);
      84   262411008 :     bit_field_ = IsInObjectBits::encode(is_inobject) |
      85   262411008 :       IsDoubleBits::encode(is_double) |
      86             :       FirstInobjectPropertyOffsetBits::encode(first_inobject_property_offset) |
      87   262604140 :       IsHiddenField::encode(is_hidden) |
      88   262411008 :       IndexBits::encode(local_index) |
      89   262604140 :       InObjectPropertyBits::encode(inobject_properties);
      90             :   }
      91             : 
      92             :   explicit FieldIndex(int bit_field) : bit_field_(bit_field) {}
      93             : 
      94             :   int first_inobject_property_offset() const {
      95             :     DCHECK(!is_hidden_field());
      96          14 :     return FirstInobjectPropertyOffsetBits::decode(bit_field_);
      97             :   }
      98             : 
      99             :   static const int kIndexBitsSize = kDescriptorIndexBitCount + 1;
     100             : 
     101             :   // Index from beginning of object.
     102             :   class IndexBits: public BitField<int, 0, kIndexBitsSize> {};
     103             :   class IsInObjectBits: public BitField<bool, IndexBits::kNext, 1> {};
     104             :   class IsDoubleBits: public BitField<bool, IsInObjectBits::kNext, 1> {};
     105             :   // Number of inobject properties.
     106             :   class InObjectPropertyBits
     107             :       : public BitField<int, IsDoubleBits::kNext, kDescriptorIndexBitCount> {};
     108             :   // Offset of first inobject property from beginning of object.
     109             :   class FirstInobjectPropertyOffsetBits
     110             :       : public BitField<int, InObjectPropertyBits::kNext, 7> {};
     111             :   class IsHiddenField
     112             :       : public BitField<bool, FirstInobjectPropertyOffsetBits::kNext, 1> {};
     113             :   STATIC_ASSERT(IsHiddenField::kNext <= 32);
     114             : 
     115             :   int bit_field_;
     116             : };
     117             : 
     118             : }  // namespace internal
     119             : }  // namespace v8
     120             : 
     121             : #endif