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
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