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      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/flags.h"
     11 #include "src/globals.h"
     12 #include "src/handles.h"
     13 #include "src/utils.h"
     14 
     15 namespace v8 {
     16 namespace internal {
     17 
     18 class Code;
     19 class CompilationInfo;
     20 class Script;
     21 class SharedFunctionInfo;
     22 struct SourcePositionInfo;
     23 
     24 // SourcePosition stores
     25 // - script_offset (31 bit non-negative int or kNoSourcePosition)
     26 // - inlining_id (16 bit non-negative int or kNotInlined).
     27 //
     28 // A defined inlining_id refers to positions in
     29 // CompilationInfo::inlined_functions or
     30 // DeoptimizationInputData::InliningPositions, depending on the compilation
     31 // stage.
     32 class SourcePosition final {
     33  public:
     34   explicit SourcePosition(int script_offset, int inlining_id = kNotInlined)
     35       : value_(0) {
     36     SetScriptOffset(script_offset);
     37     SetInliningId(inlining_id);
     38   }
     39 
     40   static SourcePosition Unknown() { return SourcePosition(kNoSourcePosition); }
     41   bool IsKnown() const {
     42     return ScriptOffset() != kNoSourcePosition || InliningId() != kNotInlined;
     43   }
     44   bool isInlined() const { return InliningId() != kNotInlined; }
     45 
     46   std::vector<SourcePositionInfo> InliningStack(Handle<Code> code) const;
     47   std::vector<SourcePositionInfo> InliningStack(CompilationInfo* code) const;
     48 
     49   void Print(std::ostream& out, Code* function) const;
     50 
     51   int ScriptOffset() const { return ScriptOffsetField::decode(value_) - 1; }
     52   int InliningId() const { return InliningIdField::decode(value_) - 1; }
     53 
     54   void SetScriptOffset(int script_offset) {
     55     DCHECK(script_offset <= ScriptOffsetField::kMax - 2);
     56     DCHECK(script_offset >= kNoSourcePosition);
     57     value_ = ScriptOffsetField::update(value_, script_offset + 1);
     58   }
     59   void SetInliningId(int inlining_id) {
     60     DCHECK(inlining_id <= InliningIdField::kMax - 2);
     61     DCHECK(inlining_id >= kNotInlined);
     62     value_ = InliningIdField::update(value_, inlining_id + 1);
     63   }
     64 
     65   static const int kNotInlined = -1;
     66   STATIC_ASSERT(kNoSourcePosition == -1);
     67 
     68   int64_t raw() const { return static_cast<int64_t>(value_); }
     69   static SourcePosition FromRaw(int64_t raw) {
     70     SourcePosition position = Unknown();
     71     DCHECK_GE(raw, 0);
     72     position.value_ = static_cast<uint64_t>(raw);
     73     return position;
     74   }
     75 
     76  private:
     77   void Print(std::ostream& out, SharedFunctionInfo* function) const;
     78   SourcePositionInfo Info(Handle<SharedFunctionInfo> script) const;
     79 
     80   // InliningId is in the high bits for better compression in
     81   // SourcePositionTable.
     82   typedef BitField64<int, 0, 31> ScriptOffsetField;
     83   typedef BitField64<int, 31, 16> InliningIdField;
     84   // Leaving the highest bit untouched to allow for signed conversion.
     85   uint64_t value_;
     86 };
     87 
     88 inline bool operator==(const SourcePosition& lhs, const SourcePosition& rhs) {
     89   return lhs.raw() == rhs.raw();
     90 }
     91 
     92 inline bool operator!=(const SourcePosition& lhs, const SourcePosition& rhs) {
     93   return !(lhs == rhs);
     94 }
     95 
     96 struct InliningPosition {
     97   // position of the inlined call
     98   SourcePosition position = SourcePosition::Unknown();
     99 
    100   // references position in DeoptimizationInputData::literals()
    101   int inlined_function_id;
    102 };
    103 
    104 struct SourcePositionInfo {
    105   explicit SourcePositionInfo(SourcePosition pos, Handle<SharedFunctionInfo> f)
    106       : position(pos), function(f) {}
    107 
    108   SourcePosition position;
    109   Handle<SharedFunctionInfo> function;
    110   int line = -1;
    111   int column = -1;
    112 };
    113 
    114 std::ostream& operator<<(std::ostream& out, const SourcePosition& pos);
    115 
    116 std::ostream& operator<<(std::ostream& out, const SourcePositionInfo& pos);
    117 std::ostream& operator<<(std::ostream& out,
    118                          const std::vector<SourcePositionInfo>& stack);
    119 
    120 }  // namespace internal
    121 }  // namespace v8
    122 
    123 #endif  // V8_SOURCE_POSITION_H_
    124