Line data Source code
1 : // Copyright 2015 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_INTERPRETER_CONSTANT_ARRAY_BUILDER_H_
6 : #define V8_INTERPRETER_CONSTANT_ARRAY_BUILDER_H_
7 :
8 : #include "src/globals.h"
9 : #include "src/identity-map.h"
10 : #include "src/interpreter/bytecodes.h"
11 : #include "src/zone/zone-containers.h"
12 :
13 : namespace v8 {
14 : namespace internal {
15 :
16 : class Isolate;
17 : class AstRawString;
18 : class AstValue;
19 :
20 : namespace interpreter {
21 :
22 : // Constant array entries that represent singletons.
23 : #define SINGLETON_CONSTANT_ENTRY_TYPES(V) \
24 : V(IteratorSymbol, iterator_symbol) \
25 : V(AsyncIteratorSymbol, async_iterator_symbol) \
26 : V(HomeObjectSymbol, home_object_symbol) \
27 : V(EmptyFixedArray, empty_fixed_array)
28 :
29 : // A helper class for constructing constant arrays for the
30 : // interpreter. Each instance of this class is intended to be used to
31 : // generate exactly one FixedArray of constants via the ToFixedArray
32 : // method.
33 : class V8_EXPORT_PRIVATE ConstantArrayBuilder final BASE_EMBEDDED {
34 : public:
35 : // Capacity of the 8-bit operand slice.
36 : static const size_t k8BitCapacity = 1u << kBitsPerByte;
37 :
38 : // Capacity of the 16-bit operand slice.
39 : static const size_t k16BitCapacity = (1u << 2 * kBitsPerByte) - k8BitCapacity;
40 :
41 : // Capacity of the 32-bit operand slice.
42 : static const size_t k32BitCapacity =
43 : kMaxUInt32 - k16BitCapacity - k8BitCapacity + 1;
44 :
45 : ConstantArrayBuilder(Zone* zone);
46 :
47 : // Generate a fixed array of constant handles based on inserted objects.
48 : Handle<FixedArray> ToFixedArray(Isolate* isolate);
49 :
50 : // Returns the object, as a handle in |isolate|, that is in the constant pool
51 : // array at index |index|. Returns null if there is no handle at this index.
52 : // Only expected to be used in tests.
53 : MaybeHandle<Object> At(size_t index, Isolate* isolate) const;
54 :
55 : // Returns the number of elements in the array.
56 : size_t size() const;
57 :
58 : // Insert an object into the constants array if it is not already present.
59 : // Returns the array index associated with the object.
60 : size_t Insert(Smi* smi);
61 : size_t Insert(const AstRawString* raw_string);
62 : size_t Insert(const AstValue* heap_number);
63 : size_t Insert(const Scope* scope);
64 : #define INSERT_ENTRY(NAME, ...) size_t Insert##NAME();
65 : SINGLETON_CONSTANT_ENTRY_TYPES(INSERT_ENTRY)
66 : #undef INSERT_ENTRY
67 :
68 : // Inserts an empty entry and returns the array index associated with the
69 : // reservation. The entry's handle value can be inserted by calling
70 : // SetDeferredAt().
71 : size_t InsertDeferred();
72 :
73 : // Sets the deferred value at |index| to |object|.
74 : void SetDeferredAt(size_t index, Handle<Object> object);
75 :
76 : // Creates a reserved entry in the constant pool and returns
77 : // the size of the operand that'll be required to hold the entry
78 : // when committed.
79 : OperandSize CreateReservedEntry();
80 :
81 : // Commit reserved entry and returns the constant pool index for the
82 : // SMI value.
83 : size_t CommitReservedEntry(OperandSize operand_size, Smi* value);
84 :
85 : // Discards constant pool reservation.
86 : void DiscardReservedEntry(OperandSize operand_size);
87 :
88 : private:
89 : typedef uint32_t index_t;
90 :
91 : class Entry {
92 : private:
93 : enum class Tag : uint8_t;
94 :
95 : public:
96 157444 : explicit Entry(Smi* smi) : smi_(smi), tag_(Tag::kSmi) {}
97 : explicit Entry(const AstRawString* raw_string)
98 7113061 : : raw_string_(raw_string), tag_(Tag::kRawString) {}
99 : explicit Entry(const AstValue* heap_number)
100 861557 : : heap_number_(heap_number), tag_(Tag::kHeapNumber) {}
101 184271 : explicit Entry(const Scope* scope) : scope_(scope), tag_(Tag::kScope) {}
102 :
103 : #define CONSTRUCT_ENTRY(NAME, LOWER_NAME) \
104 : static Entry NAME() { return Entry(Tag::k##NAME); }
105 : SINGLETON_CONSTANT_ENTRY_TYPES(CONSTRUCT_ENTRY)
106 : #undef CONSTRUCT_ENTRY
107 :
108 : static Entry Deferred() { return Entry(Tag::kDeferred); }
109 :
110 : bool IsDeferred() const { return tag_ == Tag::kDeferred; }
111 :
112 : void SetDeferred(Handle<Object> handle) {
113 : DCHECK(tag_ == Tag::kDeferred);
114 3994782 : tag_ = Tag::kHandle;
115 3994782 : handle_ = handle;
116 : }
117 :
118 : Handle<Object> ToHandle(Isolate* isolate) const;
119 :
120 : private:
121 : explicit Entry(Tag tag) : tag_(tag) {}
122 :
123 : union {
124 : Handle<Object> handle_;
125 : Smi* smi_;
126 : const AstRawString* raw_string_;
127 : const AstValue* heap_number_;
128 : const Scope* scope_;
129 : };
130 :
131 : enum class Tag : uint8_t {
132 : kDeferred,
133 : kHandle,
134 : kSmi,
135 : kRawString,
136 : kHeapNumber,
137 : kScope,
138 : #define ENTRY_TAG(NAME, ...) k##NAME,
139 : SINGLETON_CONSTANT_ENTRY_TYPES(ENTRY_TAG)
140 : #undef ENTRY_TAG
141 : } tag_;
142 : };
143 :
144 : index_t AllocateIndex(Entry constant_entry);
145 : index_t AllocateReservedEntry(Smi* value);
146 :
147 : struct ConstantArraySlice final : public ZoneObject {
148 : ConstantArraySlice(Zone* zone, size_t start_index, size_t capacity,
149 : OperandSize operand_size);
150 : void Reserve();
151 : void Unreserve();
152 : size_t Allocate(Entry entry);
153 : Entry& At(size_t index);
154 : const Entry& At(size_t index) const;
155 :
156 : #if DEBUG
157 : void CheckAllElementsAreUnique(Isolate* isolate) const;
158 : #endif
159 :
160 17321405 : inline size_t available() const { return capacity() - reserved() - size(); }
161 : inline size_t reserved() const { return reserved_; }
162 : inline size_t capacity() const { return capacity_; }
163 38661814 : inline size_t size() const { return constants_.size(); }
164 : inline size_t start_index() const { return start_index_; }
165 5008598 : inline size_t max_index() const { return start_index_ + capacity() - 1; }
166 : inline OperandSize operand_size() const { return operand_size_; }
167 :
168 : private:
169 : const size_t start_index_;
170 : const size_t capacity_;
171 : size_t reserved_;
172 : OperandSize operand_size_;
173 : ZoneVector<Entry> constants_;
174 :
175 : DISALLOW_COPY_AND_ASSIGN(ConstantArraySlice);
176 : };
177 :
178 : ConstantArraySlice* IndexToSlice(size_t index) const;
179 : ConstantArraySlice* OperandSizeToSlice(OperandSize operand_size) const;
180 :
181 : ConstantArraySlice* idx_slice_[3];
182 : base::TemplateHashMapImpl<intptr_t, index_t,
183 : base::KeyEqualityMatcher<intptr_t>,
184 : ZoneAllocationPolicy>
185 : constants_map_;
186 : ZoneMap<Smi*, index_t> smi_map_;
187 : ZoneVector<std::pair<Smi*, index_t>> smi_pairs_;
188 :
189 : #define SINGLETON_ENTRY_FIELD(NAME, LOWER_NAME) int LOWER_NAME##_;
190 : SINGLETON_CONSTANT_ENTRY_TYPES(SINGLETON_ENTRY_FIELD)
191 : #undef SINGLETON_ENTRY_FIELD
192 :
193 : Zone* zone_;
194 : };
195 :
196 : } // namespace interpreter
197 : } // namespace internal
198 : } // namespace v8
199 :
200 : #endif // V8_INTERPRETER_CONSTANT_ARRAY_BUILDER_H_
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