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//===- 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/StringRef.h"

#include "llvm/BinaryFormat/Dwarf.h"

#include "llvm/DebugInfo/DIContext.h"

#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"

#include "llvm/DebugInfo/DWARF/DWARFUnit.h"

#include "llvm/Support/MD5.h"

#include "llvm/Support/Path.h"

#include <cstdint>

#include <map>

#include <string>

#include <vector>

namespace llvm {

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;

    /// 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;

    std::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);

    }

    std::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;

    /// Extracts directory name by its Entry in include directories table

    /// in prologue. Returns true on success.

    bool getDirectoryForEntry(const FileNameEntry &Entry,

                              std::string &Directory) 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;

    std::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);

  void clearLineTable(uint64_t Offset);

  /// 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