1 // Copyright 2016 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_SOURCE_POSITION_H_ 6 #define V8_SOURCE_POSITION_H_ 7 8 #include <ostream> 9 10 #include "src/assembler.h" 11 #include "src/flags.h" 12 #include "src/utils.h" 13 14 namespace v8 { 15 namespace internal { 16 17 // This class encapsulates encoding and decoding of sources positions from 18 // which hydrogen values originated. 19 // When FLAG_track_hydrogen_positions is set this object encodes the 20 // identifier of the inlining and absolute offset from the start of the 21 // inlined function. 22 // When the flag is not set we simply track absolute offset from the 23 // script start. 24 class SourcePosition { 25 public: 26 static SourcePosition Unknown() { 27 return SourcePosition::FromRaw(kNoPosition); 28 } 29 30 bool IsUnknown() const { return value_ == kNoPosition; } 31 32 uint32_t position() const { return PositionField::decode(value_); } 33 void set_position(uint32_t position) { 34 if (FLAG_hydrogen_track_positions) { 35 value_ = static_cast<uint32_t>(PositionField::update(value_, position)); 36 } else { 37 value_ = position; 38 } 39 } 40 41 uint32_t inlining_id() const { return InliningIdField::decode(value_); } 42 void set_inlining_id(uint32_t inlining_id) { 43 if (FLAG_hydrogen_track_positions) { 44 value_ = 45 static_cast<uint32_t>(InliningIdField::update(value_, inlining_id)); 46 } 47 } 48 49 uint32_t raw() const { return value_; } 50 51 private: 52 static const uint32_t kNoPosition = 53 static_cast<uint32_t>(RelocInfo::kNoPosition); 54 typedef BitField<uint32_t, 0, 9> InliningIdField; 55 56 // Offset from the start of the inlined function. 57 typedef BitField<uint32_t, 9, 23> PositionField; 58 59 friend class HPositionInfo; 60 friend class Deoptimizer; 61 62 static SourcePosition FromRaw(uint32_t raw_position) { 63 SourcePosition position; 64 position.value_ = raw_position; 65 return position; 66 } 67 68 // If FLAG_hydrogen_track_positions is set contains bitfields InliningIdField 69 // and PositionField. 70 // Otherwise contains absolute offset from the script start. 71 uint32_t value_; 72 }; 73 74 inline std::ostream& operator<<(std::ostream& os, const SourcePosition& p) { 75 if (p.IsUnknown()) { 76 return os << "<?>"; 77 } else if (FLAG_hydrogen_track_positions) { 78 return os << "<" << p.inlining_id() << ":" << p.position() << ">"; 79 } else { 80 return os << "<0:" << p.raw() << ">"; 81 } 82 } 83 84 } // namespace internal 85 } // namespace v8 86 87 #endif // V8_SOURCE_POSITION_H_ 88
