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| 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/identity-map.h" |
| 9 #include "src/interpreter/bytecodes.h" |
| 10 #include "src/zone-containers.h" |
| 11 |
| 12 namespace v8 { |
| 13 namespace internal { |
| 14 |
| 15 class Factory; |
| 16 class Isolate; |
| 17 |
| 18 namespace interpreter { |
| 19 |
| 20 // A helper class for constructing constant arrays for the interpreter. |
| 21 class ConstantArrayBuilder final : public ZoneObject { |
| 22 public: |
| 23 // Capacity of the 8-bit operand slice. |
| 24 static const size_t kLowCapacity = 1u << kBitsPerByte; |
| 25 |
| 26 // Capacity of the combined 8-bit and 16-bit operand slices. |
| 27 static const size_t kMaxCapacity = 1u << (2 * kBitsPerByte); |
| 28 |
| 29 // Capacity of the 16-bit operand slice. |
| 30 static const size_t kHighCapacity = kMaxCapacity - kLowCapacity; |
| 31 |
| 32 ConstantArrayBuilder(Isolate* isolate, Zone* zone); |
| 33 |
| 34 // Generate a fixed array of constants based on inserted objects. |
| 35 Handle<FixedArray> ToFixedArray(Factory* factory) const; |
| 36 |
| 37 // Returns the object in the constant pool array that at index |
| 38 // |index|. |
| 39 Handle<Object> At(size_t index) const; |
| 40 |
| 41 // Returns the number of elements in the array. |
| 42 size_t size() const; |
| 43 |
| 44 // Insert an object into the constants array if it is not already |
| 45 // present. Returns the array index associated with the object. |
| 46 size_t Insert(Handle<Object> object); |
| 47 |
| 48 // Creates a reserved entry in the constant pool and returns |
| 49 // the size of the operand that'll be required to hold the entry |
| 50 // when committed. |
| 51 OperandSize CreateReservedEntry(); |
| 52 |
| 53 // Commit reserved entry and returns the constant pool index for the |
| 54 // object. |
| 55 size_t CommitReservedEntry(OperandSize operand_size, Handle<Object> object); |
| 56 |
| 57 // Discards constant pool reservation. |
| 58 void DiscardReservedEntry(OperandSize operand_size); |
| 59 |
| 60 private: |
| 61 typedef uint16_t index_t; |
| 62 |
| 63 index_t AllocateEntry(Handle<Object> object); |
| 64 |
| 65 struct ConstantArraySlice final { |
| 66 ConstantArraySlice(Zone* zone, size_t start_index, size_t capacity); |
| 67 void Reserve(); |
| 68 void Unreserve(); |
| 69 size_t Allocate(Handle<Object> object); |
| 70 Handle<Object> At(size_t index) const; |
| 71 |
| 72 inline size_t available() const { return capacity() - reserved() - size(); } |
| 73 inline size_t reserved() const { return reserved_; } |
| 74 inline size_t capacity() const { return capacity_; } |
| 75 inline size_t size() const { return constants_.size(); } |
| 76 inline size_t start_index() const { return start_index_; } |
| 77 |
| 78 private: |
| 79 const size_t start_index_; |
| 80 const size_t capacity_; |
| 81 size_t reserved_; |
| 82 ZoneVector<Handle<Object>> constants_; |
| 83 |
| 84 DISALLOW_COPY_AND_ASSIGN(ConstantArraySlice); |
| 85 }; |
| 86 |
| 87 Isolate* isolate_; |
| 88 ConstantArraySlice idx8_slice_; |
| 89 ConstantArraySlice idx16_slice_; |
| 90 IdentityMap<index_t> constants_map_; |
| 91 }; |
| 92 |
| 93 } // namespace interpreter |
| 94 } // namespace internal |
| 95 } // namespace v8 |
| 96 |
| 97 #endif // V8_INTERPRETER_CONSTANT_ARRAY_BUILDER_H_ |
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