text: //===- DWARFDebugLine.h -----------------------------------------*- C++ -*-===//
  //
  // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  // See https://llvm.org/LICENSE.txt for license information.
  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  //
  //===----------------------------------------------------------------------===//
  
  #ifndef LLVM_DEBUGINFO_DWARF_DWARFDEBUGLINE_H
  #define LLVM_DEBUGINFO_DWARF_DWARFDEBUGLINE_H
  
  #include "llvm/ADT/Optional.h"
  #include "llvm/ADT/StringRef.h"
  #include "llvm/DebugInfo/DIContext.h"
  #include "llvm/DebugInfo/DWARF/DWARFCompileUnit.h"
  #include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
  #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
  #include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
  #include "llvm/DebugInfo/DWARF/DWARFTypeUnit.h"
  #include "llvm/Support/MD5.h"
  #include "llvm/Support/Path.h"
  #include <cstdint>
  #include <map>
  #include <string>
  #include <vector>
  
  namespace llvm {
  
  class DWARFUnit;
  class raw_ostream;
  
  class DWARFDebugLine {
  public:
    struct FileNameEntry {
      FileNameEntry() = default;
  
      DWARFFormValue Name;
      uint64_t DirIdx = 0;
      uint64_t ModTime = 0;
      uint64_t Length = 0;
      MD5::MD5Result Checksum;
      DWARFFormValue Source;
    };
  
    /// Tracks which optional content types are present in a DWARF file name
    /// entry format.
    struct ContentTypeTracker {
      ContentTypeTracker() = default;
  
      /// Whether filename entries provide a modification timestamp.
      bool HasModTime = false;
      /// Whether filename entries provide a file size.
      bool HasLength = false;
      /// For v5, whether filename entries provide an MD5 checksum.
      bool HasMD5 = false;
      /// For v5, whether filename entries provide source text.
      bool HasSource = false;
  
      /// Update tracked content types with \p ContentType.
      void trackContentType(dwarf::LineNumberEntryFormat ContentType);
    };
  
    struct Prologue {
      Prologue();
  
      /// The size in bytes of the statement information for this compilation unit
      /// (not including the total_length field itself).
      uint64_t TotalLength;
      /// Version, address size (starting in v5), and DWARF32/64 format; these
      /// parameters affect interpretation of forms (used in the directory and
      /// file tables starting with v5).
      dwarf::FormParams FormParams;
      /// The number of bytes following the prologue_length field to the beginning
      /// of the first byte of the statement program itself.
      uint64_t PrologueLength;
      /// In v5, size in bytes of a segment selector.
      uint8_t SegSelectorSize;
      /// The size in bytes of the smallest target machine instruction. Statement
      /// program opcodes that alter the address register first multiply their
      /// operands by this value.
      uint8_t MinInstLength;
      /// The maximum number of individual operations that may be encoded in an
      /// instruction.
      uint8_t MaxOpsPerInst;
      /// The initial value of theis_stmtregister.
      uint8_t DefaultIsStmt;
      /// This parameter affects the meaning of the special opcodes. See below.
      int8_t LineBase;
      /// This parameter affects the meaning of the special opcodes. See below.
      uint8_t LineRange;
      /// The number assigned to the first special opcode.
      uint8_t OpcodeBase;
      /// This tracks which optional file format content types are present.
      ContentTypeTracker ContentTypes;
      std::vector<uint8_t> StandardOpcodeLengths;
      std::vector<DWARFFormValue> IncludeDirectories;
      std::vector<FileNameEntry> FileNames;
  
      const dwarf::FormParams getFormParams() const { return FormParams; }
      uint16_t getVersion() const { return FormParams.Version; }
      uint8_t getAddressSize() const { return FormParams.AddrSize; }
      bool isDWARF64() const { return FormParams.Format == dwarf::DWARF64; }
  
      uint32_t sizeofTotalLength() const { return isDWARF64() ? 12 : 4; }
  
      uint32_t sizeofPrologueLength() const { return isDWARF64() ? 8 : 4; }
  
      bool totalLengthIsValid() const;
  
      /// Length of the prologue in bytes.
      uint64_t getLength() const;
  
      int32_t getMaxLineIncrementForSpecialOpcode() const {
        return LineBase + (int8_t)LineRange - 1;
      }
  
      /// Get DWARF-version aware access to the file name entry at the provided
      /// index.
      const llvm::DWARFDebugLine::FileNameEntry &
      getFileNameEntry(uint64_t Index) const;
  
      bool hasFileAtIndex(uint64_t FileIndex) const;
  
      Optional<uint64_t> getLastValidFileIndex() const;
  
      bool
      getFileNameByIndex(uint64_t FileIndex, StringRef CompDir,
                         DILineInfoSpecifier::FileLineInfoKind Kind,
                         std::string &Result,
                         sys::path::Style Style = sys::path::Style::native) const;
  
      void clear();
      void dump(raw_ostream &OS, DIDumpOptions DumpOptions) const;
      Error parse(DWARFDataExtractor Data, uint64_t *OffsetPtr,
                  function_ref<void(Error)> RecoverableErrorHandler,
                  const DWARFContext &Ctx, const DWARFUnit *U = nullptr);
    };
  
    /// Standard .debug_line state machine structure.
    struct Row {
      explicit Row(bool DefaultIsStmt = false);
  
      /// Called after a row is appended to the matrix.
      void postAppend();
      void reset(bool DefaultIsStmt);
      void dump(raw_ostream &OS) const;
  
      static void dumpTableHeader(raw_ostream &OS, unsigned Indent);
  
      static bool orderByAddress(const Row &LHS, const Row &RHS) {
        return std::tie(LHS.Address.SectionIndex, LHS.Address.Address) <
               std::tie(RHS.Address.SectionIndex, RHS.Address.Address);
      }
  
      /// The program-counter value corresponding to a machine instruction
      /// generated by the compiler and section index pointing to the section
      /// containg this PC. If relocation information is present then section
      /// index is the index of the section which contains above address.
      /// Otherwise this is object::SectionedAddress::Undef value.
      object::SectionedAddress Address;
      /// An unsigned integer indicating a source line number. Lines are numbered
      /// beginning at 1. The compiler may emit the value 0 in cases where an
      /// instruction cannot be attributed to any source line.
      uint32_t Line;
      /// An unsigned integer indicating a column number within a source line.
      /// Columns are numbered beginning at 1. The value 0 is reserved to indicate
      /// that a statement begins at the 'left edge' of the line.
      uint16_t Column;
      /// An unsigned integer indicating the identity of the source file
      /// corresponding to a machine instruction.
      uint16_t File;
      /// An unsigned integer representing the DWARF path discriminator value
      /// for this location.
      uint32_t Discriminator;
      /// An unsigned integer whose value encodes the applicable instruction set
      /// architecture for the current instruction.
      uint8_t Isa;
      /// A boolean indicating that the current instruction is the beginning of a
      /// statement.
      uint8_t IsStmt : 1,
          /// A boolean indicating that the current instruction is the
          /// beginning of a basic block.
          BasicBlock : 1,
          /// A boolean indicating that the current address is that of the
          /// first byte after the end of a sequence of target machine
          /// instructions.
          EndSequence : 1,
          /// A boolean indicating that the current address is one (of possibly
          /// many) where execution should be suspended for an entry breakpoint
          /// of a function.
          PrologueEnd : 1,
          /// A boolean indicating that the current address is one (of possibly
          /// many) where execution should be suspended for an exit breakpoint
          /// of a function.
          EpilogueBegin : 1;
    };
  
    /// Represents a series of contiguous machine instructions. Line table for
    /// each compilation unit may consist of multiple sequences, which are not
    /// guaranteed to be in the order of ascending instruction address.
    struct Sequence {
      Sequence();
  
      /// Sequence describes instructions at address range [LowPC, HighPC)
      /// and is described by line table rows [FirstRowIndex, LastRowIndex).
      uint64_t LowPC;
      uint64_t HighPC;
      /// If relocation information is present then this is the index of the
      /// section which contains above addresses. Otherwise this is
      /// object::SectionedAddress::Undef value.
      uint64_t SectionIndex;
      unsigned FirstRowIndex;
      unsigned LastRowIndex;
      bool Empty;
  
      void reset();
  
      static bool orderByHighPC(const Sequence &LHS, const Sequence &RHS) {
        return std::tie(LHS.SectionIndex, LHS.HighPC) <
               std::tie(RHS.SectionIndex, RHS.HighPC);
      }
  
      bool isValid() const {
        return !Empty && (LowPC < HighPC) && (FirstRowIndex < LastRowIndex);
      }
  
      bool containsPC(object::SectionedAddress PC) const {
        return SectionIndex == PC.SectionIndex &&
               (LowPC <= PC.Address && PC.Address < HighPC);
      }
    };
  
    struct LineTable {
      LineTable();
  
      /// Represents an invalid row
      const uint32_t UnknownRowIndex = UINT32_MAX;
  
      void appendRow(const DWARFDebugLine::Row &R) { Rows.push_back(R); }
  
      void appendSequence(const DWARFDebugLine::Sequence &S) {
        Sequences.push_back(S);
      }
  
      /// Returns the index of the row with file/line info for a given address,
      /// or UnknownRowIndex if there is no such row.
      uint32_t lookupAddress(object::SectionedAddress Address) const;
  
      bool lookupAddressRange(object::SectionedAddress Address, uint64_t Size,
                              std::vector<uint32_t> &Result) const;
  
      bool hasFileAtIndex(uint64_t FileIndex) const {
        return Prologue.hasFileAtIndex(FileIndex);
      }
  
      Optional<uint64_t> getLastValidFileIndex() const {
        return Prologue.getLastValidFileIndex();
      }
  
      /// Extracts filename by its index in filename table in prologue.
      /// In Dwarf 4, the files are 1-indexed and the current compilation file
      /// name is not represented in the list. In DWARF v5, the files are
      /// 0-indexed and the primary source file has the index 0.
      /// Returns true on success.
      bool getFileNameByIndex(uint64_t FileIndex, StringRef CompDir,
                              DILineInfoSpecifier::FileLineInfoKind Kind,
                              std::string &Result) const {
        return Prologue.getFileNameByIndex(FileIndex, CompDir, Kind, Result);
      }
  
      /// Fills the Result argument with the file and line information
      /// corresponding to Address. Returns true on success.
      bool getFileLineInfoForAddress(object::SectionedAddress Address,
                                     const char *CompDir,
                                     DILineInfoSpecifier::FileLineInfoKind Kind,
                                     DILineInfo &Result) const;
  
      void dump(raw_ostream &OS, DIDumpOptions DumpOptions) const;
      void clear();
  
      /// Parse prologue and all rows.
      Error parse(DWARFDataExtractor &DebugLineData, uint64_t *OffsetPtr,
                  const DWARFContext &Ctx, const DWARFUnit *U,
                  function_ref<void(Error)> RecoverableErrorHandler,
                  raw_ostream *OS = nullptr, bool Verbose = false);
  
      using RowVector = std::vector<Row>;
      using RowIter = RowVector::const_iterator;
      using SequenceVector = std::vector<Sequence>;
      using SequenceIter = SequenceVector::const_iterator;
  
      struct Prologue Prologue;
      RowVector Rows;
      SequenceVector Sequences;
  
    private:
      uint32_t findRowInSeq(const DWARFDebugLine::Sequence &Seq,
                            object::SectionedAddress Address) const;
      Optional<StringRef>
      getSourceByIndex(uint64_t FileIndex,
                       DILineInfoSpecifier::FileLineInfoKind Kind) const;
  
      uint32_t lookupAddressImpl(object::SectionedAddress Address) const;
  
      bool lookupAddressRangeImpl(object::SectionedAddress Address, uint64_t Size,
                                  std::vector<uint32_t> &Result) const;
    };
  
    const LineTable *getLineTable(uint64_t Offset) const;
    Expected<const LineTable *>
    getOrParseLineTable(DWARFDataExtractor &DebugLineData, uint64_t Offset,
                        const DWARFContext &Ctx, const DWARFUnit *U,
                        function_ref<void(Error)> RecoverableErrorHandler);
  
    /// Helper to allow for parsing of an entire .debug_line section in sequence.
    class SectionParser {
    public:
      using LineToUnitMap = std::map<uint64_t, DWARFUnit *>;
  
      SectionParser(DWARFDataExtractor &Data, const DWARFContext &C,
                    DWARFUnitVector::iterator_range Units);
  
      /// Get the next line table from the section. Report any issues via the
      /// handlers.
      ///
      /// \param RecoverableErrorHandler - any issues that don't prevent further
      /// parsing of the table will be reported through this handler.
      /// \param UnrecoverableErrorHandler - any issues that prevent further
      /// parsing of the table will be reported through this handler.
      /// \param OS - if not null, the parser will print information about the
      /// table as it parses it.
      /// \param Verbose - if true, the parser will print verbose information when
      /// printing to the output.
      LineTable parseNext(function_ref<void(Error)> RecoverableErrorHandler,
                          function_ref<void(Error)> UnrecoverableErrorHandler,
                          raw_ostream *OS = nullptr, bool Verbose = false);
  
      /// Skip the current line table and go to the following line table (if
      /// present) immediately.
      ///
      /// \param RecoverableErrorHandler - report any recoverable prologue
      /// parsing issues via this handler.
      /// \param UnrecoverableErrorHandler - report any unrecoverable prologue
      /// parsing issues via this handler.
      void skip(function_ref<void(Error)> RecoverableErrorHandler,
                function_ref<void(Error)> UnrecoverableErrorHandler);
  
      /// Indicates if the parser has parsed as much as possible.
      ///
      /// \note Certain problems with the line table structure might mean that
      /// parsing stops before the end of the section is reached.
      bool done() const { return Done; }
  
      /// Get the offset the parser has reached.
      uint64_t getOffset() const { return Offset; }
  
    private:
      DWARFUnit *prepareToParse(uint64_t Offset);
      void moveToNextTable(uint64_t OldOffset, const Prologue &P);
  
      LineToUnitMap LineToUnit;
  
      DWARFDataExtractor &DebugLineData;
      const DWARFContext &Context;
      uint64_t Offset = 0;
      bool Done = false;
    };
  
  private:
    struct ParsingState {
      ParsingState(struct LineTable *LT, uint64_t TableOffset,
                   function_ref<void(Error)> ErrorHandler);
  
      void resetRowAndSequence();
      void appendRowToMatrix();
  
      /// Advance the address by the \p OperationAdvance value. \returns the
      /// amount advanced by.
      uint64_t advanceAddr(uint64_t OperationAdvance, uint8_t Opcode,
                           uint64_t OpcodeOffset);
  
      struct AddrAndAdjustedOpcode {
        uint64_t AddrDelta;
        uint8_t AdjustedOpcode;
      };
  
      /// Advance the address as required by the specified \p Opcode.
      /// \returns the amount advanced by and the calculated adjusted opcode.
      AddrAndAdjustedOpcode advanceAddrForOpcode(uint8_t Opcode,
                                                 uint64_t OpcodeOffset);
  
      struct AddrAndLineDelta {
        uint64_t Address;
        int32_t Line;
      };
  
      /// Advance the line and address as required by the specified special \p
      /// Opcode. \returns the address and line delta.
      AddrAndLineDelta handleSpecialOpcode(uint8_t Opcode, uint64_t OpcodeOffset);
  
      /// Line table we're currently parsing.
      struct LineTable *LineTable;
      struct Row Row;
      struct Sequence Sequence;
  
    private:
      uint64_t LineTableOffset;
  
      bool ReportAdvanceAddrProblem = true;
      bool ReportBadLineRange = true;
      function_ref<void(Error)> ErrorHandler;
    };
  
    using LineTableMapTy = std::map<uint64_t, LineTable>;
    using LineTableIter = LineTableMapTy::iterator;
    using LineTableConstIter = LineTableMapTy::const_iterator;
  
    LineTableMapTy LineTableMap;
  };
  
  } // end namespace llvm
  
  #endif // LLVM_DEBUGINFO_DWARF_DWARFDEBUGLINE_H
  