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// Copyright 2015 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_INTERPRETER_CONSTANT_ARRAY_BUILDER_H_
#define V8_INTERPRETER_CONSTANT_ARRAY_BUILDER_H_
#include "src/globals.h"
#include "src/identity-map.h"
#include "src/interpreter/bytecodes.h"
#include "src/zone/zone-containers.h"
namespace v8 {
namespace internal {
class Isolate;
namespace interpreter {
// A helper class for constructing constant arrays for the
// interpreter. Each instance of this class is intended to be used to
// generate exactly one FixedArray of constants via the ToFixedArray
// method.
class V8_EXPORT_PRIVATE ConstantArrayBuilder final BASE_EMBEDDED {
public:
// Capacity of the 8-bit operand slice.
static const size_t k8BitCapacity = 1u << kBitsPerByte;
// Capacity of the 16-bit operand slice.
static const size_t k16BitCapacity = (1u << 2 * kBitsPerByte) - k8BitCapacity;
// Capacity of the 32-bit operand slice.
static const size_t k32BitCapacity =
kMaxUInt32 - k16BitCapacity - k8BitCapacity + 1;
ConstantArrayBuilder(Zone* zone, Handle<Object> the_hole_value);
// Generate a fixed array of constants based on inserted objects.
Handle<FixedArray> ToFixedArray(Isolate* isolate);
// Returns the object in the constant pool array that at index
// |index|.
Handle<Object> At(size_t index) const;
// Returns the number of elements in the array.
size_t size() const;
// Insert an object into the constants array if it is not already
// present. Returns the array index associated with the object.
size_t Insert(Handle<Object> object);
// Allocates an empty entry and returns the array index associated with the
// reservation. Entry can be inserted by calling InsertReservedEntry().
size_t AllocateEntry();
// Inserts the given object into an allocated entry.
void InsertAllocatedEntry(size_t index, Handle<Object> object);
// Creates a reserved entry in the constant pool and returns
// the size of the operand that'll be required to hold the entry
// when committed.
OperandSize CreateReservedEntry();
// Commit reserved entry and returns the constant pool index for the
// SMI value.
size_t CommitReservedEntry(OperandSize operand_size, Smi* value);
// Discards constant pool reservation.
void DiscardReservedEntry(OperandSize operand_size);
private:
typedef uint32_t index_t;
index_t AllocateIndex(Handle<Object> object);
index_t AllocateReservedEntry(Smi* value);
struct ConstantArraySlice final : public ZoneObject {
ConstantArraySlice(Zone* zone, size_t start_index, size_t capacity,
OperandSize operand_size);
void Reserve();
void Unreserve();
size_t Allocate(Handle<Object> object);
Handle<Object> At(size_t index) const;
void InsertAt(size_t index, Handle<Object> object);
bool AllElementsAreUnique() const;
inline size_t available() const { return capacity() - reserved() - size(); }
inline size_t reserved() const { return reserved_; }
inline size_t capacity() const { return capacity_; }
inline size_t size() const { return constants_.size(); }
inline size_t start_index() const { return start_index_; }
inline size_t max_index() const { return start_index_ + capacity() - 1; }
inline OperandSize operand_size() const { return operand_size_; }
private:
const size_t start_index_;
const size_t capacity_;
size_t reserved_;
OperandSize operand_size_;
ZoneVector<Handle<Object>> constants_;
DISALLOW_COPY_AND_ASSIGN(ConstantArraySlice);
};
ConstantArraySlice* IndexToSlice(size_t index) const;
ConstantArraySlice* OperandSizeToSlice(OperandSize operand_size) const;
Handle<Object> the_hole_value() const { return the_hole_value_; }
ConstantArraySlice* idx_slice_[3];
base::TemplateHashMapImpl<Address, index_t, base::KeyEqualityMatcher<Address>,
ZoneAllocationPolicy>
constants_map_;
ZoneMap<Smi*, index_t> smi_map_;
ZoneVector<std::pair<Smi*, index_t>> smi_pairs_;
Zone* zone_;
Handle<Object> the_hole_value_;
};
} // namespace interpreter
} // namespace internal
} // namespace v8
#endif // V8_INTERPRETER_CONSTANT_ARRAY_BUILDER_H_
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