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// Copyright 2016 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_SOURCE_POSITION_H_
#define V8_SOURCE_POSITION_H_
#include <ostream>
#include "src/assembler.h"
#include "src/flags.h"
#include "src/utils.h"
namespace v8 {
namespace internal {
// This class encapsulates encoding and decoding of sources positions from
// which hydrogen values originated.
// When FLAG_track_hydrogen_positions is set this object encodes the
// identifier of the inlining and absolute offset from the start of the
// inlined function.
// When the flag is not set we simply track absolute offset from the
// script start.
class SourcePosition {
public:
static SourcePosition Unknown() {
return SourcePosition::FromRaw(kNoPosition);
}
bool IsUnknown() const { return value_ == kNoPosition; }
uint32_t position() const { return PositionField::decode(value_); }
void set_position(uint32_t position) {
if (FLAG_hydrogen_track_positions) {
value_ = static_cast<uint32_t>(PositionField::update(value_, position));
} else {
value_ = position;
}
}
uint32_t inlining_id() const { return InliningIdField::decode(value_); }
void set_inlining_id(uint32_t inlining_id) {
if (FLAG_hydrogen_track_positions) {
value_ =
static_cast<uint32_t>(InliningIdField::update(value_, inlining_id));
}
}
uint32_t raw() const { return value_; }
private:
static const uint32_t kNoPosition =
static_cast<uint32_t>(RelocInfo::kNoPosition);
typedef BitField<uint32_t, 0, 9> InliningIdField;
// Offset from the start of the inlined function.
typedef BitField<uint32_t, 9, 23> PositionField;
friend class HPositionInfo;
friend class Deoptimizer;
static SourcePosition FromRaw(uint32_t raw_position) {
SourcePosition position;
position.value_ = raw_position;
return position;
}
// If FLAG_hydrogen_track_positions is set contains bitfields InliningIdField
// and PositionField.
// Otherwise contains absolute offset from the script start.
uint32_t value_;
};
inline std::ostream& operator<<(std::ostream& os, const SourcePosition& p) {
if (p.IsUnknown()) {
return os << "<?>";
} else if (FLAG_hydrogen_track_positions) {
return os << "<" << p.inlining_id() << ":" << p.position() << ">";
} else {
return os << "<0:" << p.raw() << ">";
}
}
} // namespace internal
} // namespace v8
#endif // V8_SOURCE_POSITION_H_
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