include/llvm/DebugInfo/DWARF/DWARFDebugLine.h

   1 //===- DWARFDebugLine.h -----------------------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_DEBUGINFO_DWARFDEBUGLINE_H
  10 #define LLVM_DEBUGINFO_DWARFDEBUGLINE_H
  11
  12 #include "llvm/ADT/Optional.h"
  13 #include "llvm/ADT/StringRef.h"
  14 #include "llvm/DebugInfo/DIContext.h"
  15 #include "llvm/DebugInfo/DWARF/DWARFCompileUnit.h"
  16 #include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
  17 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
  18 #include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
  19 #include "llvm/DebugInfo/DWARF/DWARFTypeUnit.h"
  20 #include "llvm/Support/MD5.h"
  21 #include "llvm/Support/Path.h"
  22 #include <cstdint>
  23 #include <map>
  24 #include <string>
  25 #include <vector>
  26
  27 namespace llvm {
  28
  29 class DWARFUnit;
  30 class raw_ostream;
  31
  32 class DWARFDebugLine {
  33 public:
  34   struct FileNameEntry {
  35     FileNameEntry() = default;
  36
  37     DWARFFormValue Name;
  38     uint64_t DirIdx = 0;
  39     uint64_t ModTime = 0;
  40     uint64_t Length = 0;
  41     MD5::MD5Result Checksum;
  42     DWARFFormValue Source;
  43   };
  44
  45   /// Tracks which optional content types are present in a DWARF file name
  46   /// entry format.
  47   struct ContentTypeTracker {
  48     ContentTypeTracker() = default;
  49
  50     /// Whether filename entries provide a modification timestamp.
  51     bool HasModTime = false;
  52     /// Whether filename entries provide a file size.
  53     bool HasLength = false;
  54     /// For v5, whether filename entries provide an MD5 checksum.
  55     bool HasMD5 = false;
  56     /// For v5, whether filename entries provide source text.
  57     bool HasSource = false;
  58
  59     /// Update tracked content types with \p ContentType.
  60     void trackContentType(dwarf::LineNumberEntryFormat ContentType);
  61   };
  62
  63   struct Prologue {
  64     Prologue();
  65
  66     /// The size in bytes of the statement information for this compilation unit
  67     /// (not including the total_length field itself).
  68     uint64_t TotalLength;
  69     /// Version, address size (starting in v5), and DWARF32/64 format; these
  70     /// parameters affect interpretation of forms (used in the directory and
  71     /// file tables starting with v5).
  72     dwarf::FormParams FormParams;
  73     /// The number of bytes following the prologue_length field to the beginning
  74     /// of the first byte of the statement program itself.
  75     uint64_t PrologueLength;
  76     /// In v5, size in bytes of a segment selector.
  77     uint8_t SegSelectorSize;
  78     /// The size in bytes of the smallest target machine instruction. Statement
  79     /// program opcodes that alter the address register first multiply their
  80     /// operands by this value.
  81     uint8_t MinInstLength;
  82     /// The maximum number of individual operations that may be encoded in an
  83     /// instruction.
  84     uint8_t MaxOpsPerInst;
  85     /// The initial value of theis_stmtregister.
  86     uint8_t DefaultIsStmt;
  87     /// This parameter affects the meaning of the special opcodes. See below.
  88     int8_t LineBase;
  89     /// This parameter affects the meaning of the special opcodes. See below.
  90     uint8_t LineRange;
  91     /// The number assigned to the first special opcode.
  92     uint8_t OpcodeBase;
  93     /// This tracks which optional file format content types are present.
  94     ContentTypeTracker ContentTypes;
  95     std::vector<uint8_t> StandardOpcodeLengths;
  96     std::vector<DWARFFormValue> IncludeDirectories;
  97     std::vector<FileNameEntry> FileNames;
  98
  99     const dwarf::FormParams getFormParams() const { return FormParams; }
 100     uint16_t getVersion() const { return FormParams.Version; }
 101     uint8_t getAddressSize() const { return FormParams.AddrSize; }
 102     bool isDWARF64() const { return FormParams.Format == dwarf::DWARF64; }
 103
 104     uint32_t sizeofTotalLength() const { return isDWARF64() ? 12 : 4; }
 105
 106     uint32_t sizeofPrologueLength() const { return isDWARF64() ? 8 : 4; }
 107
 108     bool totalLengthIsValid() const;
 109
 110     /// Length of the prologue in bytes.
 111     uint32_t getLength() const {
 112       return PrologueLength + sizeofTotalLength() + sizeof(getVersion()) +
 113              sizeofPrologueLength();
 114     }
 115
 116     /// Length of the line table data in bytes (not including the prologue).
 117     uint32_t getStatementTableLength() const {
 118       return TotalLength + sizeofTotalLength() - getLength();
 119     }
 120
 121     int32_t getMaxLineIncrementForSpecialOpcode() const {
 122       return LineBase + (int8_t)LineRange - 1;
 123     }
 124
 125     /// Get DWARF-version aware access to the file name entry at the provided
 126     /// index.
 127     const llvm::DWARFDebugLine::FileNameEntry &
 128     getFileNameEntry(uint64_t Index) const;
 129
 130     bool hasFileAtIndex(uint64_t FileIndex) const;
 131
 132     bool
 133     getFileNameByIndex(uint64_t FileIndex, StringRef CompDir,
 134                        DILineInfoSpecifier::FileLineInfoKind Kind,
 135                        std::string &Result,
 136                        sys::path::Style Style = sys::path::Style::native) const;
 137
 138     void clear();
 139     void dump(raw_ostream &OS, DIDumpOptions DumpOptions) const;
 140     Error parse(const DWARFDataExtractor &DebugLineData, uint64_t *OffsetPtr,
 141                 const DWARFContext &Ctx, const DWARFUnit *U = nullptr);
 142   };
 143
 144   /// Standard .debug_line state machine structure.
 145   struct Row {
 146     explicit Row(bool DefaultIsStmt = false);
 147
 148     /// Called after a row is appended to the matrix.
 149     void postAppend();
 150     void reset(bool DefaultIsStmt);
 151     void dump(raw_ostream &OS) const;
 152
 153     static void dumpTableHeader(raw_ostream &OS);
 154
 155     static bool orderByAddress(const Row &LHS, const Row &RHS) {
 156       return std::tie(LHS.Address.SectionIndex, LHS.Address.Address) <
 157              std::tie(RHS.Address.SectionIndex, RHS.Address.Address);
 158     }
 159
 160     /// The program-counter value corresponding to a machine instruction
 161     /// generated by the compiler and section index pointing to the section
 162     /// containg this PC. If relocation information is present then section
 163     /// index is the index of the section which contains above address.
 164     /// Otherwise this is object::SectionedAddress::Undef value.
 165     object::SectionedAddress Address;
 166     /// An unsigned integer indicating a source line number. Lines are numbered
 167     /// beginning at 1. The compiler may emit the value 0 in cases where an
 168     /// instruction cannot be attributed to any source line.
 169     uint32_t Line;
 170     /// An unsigned integer indicating a column number within a source line.
 171     /// Columns are numbered beginning at 1. The value 0 is reserved to indicate
 172     /// that a statement begins at the 'left edge' of the line.
 173     uint16_t Column;
 174     /// An unsigned integer indicating the identity of the source file
 175     /// corresponding to a machine instruction.
 176     uint16_t File;
 177     /// An unsigned integer representing the DWARF path discriminator value
 178     /// for this location.
 179     uint32_t Discriminator;
 180     /// An unsigned integer whose value encodes the applicable instruction set
 181     /// architecture for the current instruction.
 182     uint8_t Isa;
 183     /// A boolean indicating that the current instruction is the beginning of a
 184     /// statement.
 185     uint8_t IsStmt : 1,
 186         /// A boolean indicating that the current instruction is the
 187         /// beginning of a basic block.
 188         BasicBlock : 1,
 189         /// A boolean indicating that the current address is that of the
 190         /// first byte after the end of a sequence of target machine
 191         /// instructions.
 192         EndSequence : 1,
 193         /// A boolean indicating that the current address is one (of possibly
 194         /// many) where execution should be suspended for an entry breakpoint
 195         /// of a function.
 196         PrologueEnd : 1,
 197         /// A boolean indicating that the current address is one (of possibly
 198         /// many) where execution should be suspended for an exit breakpoint
 199         /// of a function.
 200         EpilogueBegin : 1;
 201   };
 202
 203   /// Represents a series of contiguous machine instructions. Line table for
 204   /// each compilation unit may consist of multiple sequences, which are not
 205   /// guaranteed to be in the order of ascending instruction address.
 206   struct Sequence {
 207     Sequence();
 208
 209     /// Sequence describes instructions at address range [LowPC, HighPC)
 210     /// and is described by line table rows [FirstRowIndex, LastRowIndex).
 211     uint64_t LowPC;
 212     uint64_t HighPC;
 213     /// If relocation information is present then this is the index of the
 214     /// section which contains above addresses. Otherwise this is
 215     /// object::SectionedAddress::Undef value.
 216     uint64_t SectionIndex;
 217     unsigned FirstRowIndex;
 218     unsigned LastRowIndex;
 219     bool Empty;
 220
 221     void reset();
 222
 223     static bool orderByHighPC(const Sequence &LHS, const Sequence &RHS) {
 224       return std::tie(LHS.SectionIndex, LHS.HighPC) <
 225              std::tie(RHS.SectionIndex, RHS.HighPC);
 226     }
 227
 228     bool isValid() const {
 229       return !Empty && (LowPC < HighPC) && (FirstRowIndex < LastRowIndex);
 230     }
 231
 232     bool containsPC(object::SectionedAddress PC) const {
 233       return SectionIndex == PC.SectionIndex &&
 234              (LowPC <= PC.Address && PC.Address < HighPC);
 235     }
 236   };
 237
 238   struct LineTable {
 239     LineTable();
 240
 241     /// Represents an invalid row
 242     const uint32_t UnknownRowIndex = UINT32_MAX;
 243
 244     void appendRow(const DWARFDebugLine::Row &R) { Rows.push_back(R); }
 245
 246     void appendSequence(const DWARFDebugLine::Sequence &S) {
 247       Sequences.push_back(S);
 248     }
 249
 250     /// Returns the index of the row with file/line info for a given address,
 251     /// or UnknownRowIndex if there is no such row.
 252     uint32_t lookupAddress(object::SectionedAddress Address) const;
 253
 254     bool lookupAddressRange(object::SectionedAddress Address, uint64_t Size,
 255                             std::vector<uint32_t> &Result) const;
 256
 257     bool hasFileAtIndex(uint64_t FileIndex) const {
 258       return Prologue.hasFileAtIndex(FileIndex);
 259     }
 260
 261     /// Extracts filename by its index in filename table in prologue.
 262     /// In Dwarf 4, the files are 1-indexed and the current compilation file
 263     /// name is not represented in the list. In DWARF v5, the files are
 264     /// 0-indexed and the primary source file has the index 0.
 265     /// Returns true on success.
 266     bool getFileNameByIndex(uint64_t FileIndex, StringRef CompDir,
 267                             DILineInfoSpecifier::FileLineInfoKind Kind,
 268                             std::string &Result) const {
 269       return Prologue.getFileNameByIndex(FileIndex, CompDir, Kind, Result);
 270     }
 271
 272     /// Fills the Result argument with the file and line information
 273     /// corresponding to Address. Returns true on success.
 274     bool getFileLineInfoForAddress(object::SectionedAddress Address,
 275                                    const char *CompDir,
 276                                    DILineInfoSpecifier::FileLineInfoKind Kind,
 277                                    DILineInfo &Result) const;
 278
 279     void dump(raw_ostream &OS, DIDumpOptions DumpOptions) const;
 280     void clear();
 281
 282     /// Parse prologue and all rows.
 283     Error parse(
 284         DWARFDataExtractor &DebugLineData, uint64_t *OffsetPtr,
 285         const DWARFContext &Ctx, const DWARFUnit *U,
 286         std::function<void(Error)> RecoverableErrorCallback,
 287         raw_ostream *OS = nullptr);
 288
 289     using RowVector = std::vector<Row>;
 290     using RowIter = RowVector::const_iterator;
 291     using SequenceVector = std::vector<Sequence>;
 292     using SequenceIter = SequenceVector::const_iterator;
 293
 294     struct Prologue Prologue;
 295     RowVector Rows;
 296     SequenceVector Sequences;
 297
 298   private:
 299     uint32_t findRowInSeq(const DWARFDebugLine::Sequence &Seq,
 300                           object::SectionedAddress Address) const;
 301     Optional<StringRef>
 302     getSourceByIndex(uint64_t FileIndex,
 303                      DILineInfoSpecifier::FileLineInfoKind Kind) const;
 304
 305     uint32_t lookupAddressImpl(object::SectionedAddress Address) const;
 306
 307     bool lookupAddressRangeImpl(object::SectionedAddress Address, uint64_t Size,
 308                                 std::vector<uint32_t> &Result) const;
 309   };
 310
 311   const LineTable *getLineTable(uint64_t Offset) const;
 312   Expected<const LineTable *> getOrParseLineTable(
 313       DWARFDataExtractor &DebugLineData, uint64_t Offset,
 314       const DWARFContext &Ctx, const DWARFUnit *U,
 315       std::function<void(Error)> RecoverableErrorCallback);
 316
 317   /// Helper to allow for parsing of an entire .debug_line section in sequence.
 318   class SectionParser {
 319   public:
 320     using cu_range = DWARFUnitVector::iterator_range;
 321     using tu_range = DWARFUnitVector::iterator_range;
 322     using LineToUnitMap = std::map<uint64_t, DWARFUnit *>;
 323
 324     SectionParser(DWARFDataExtractor &Data, const DWARFContext &C, cu_range CUs,
 325                   tu_range TUs);
 326
 327     /// Get the next line table from the section. Report any issues via the
 328     /// callbacks.
 329     ///
 330     /// \param RecoverableErrorCallback - any issues that don't prevent further
 331     /// parsing of the table will be reported through this callback.
 332     /// \param UnrecoverableErrorCallback - any issues that prevent further
 333     /// parsing of the table will be reported through this callback.
 334     /// \param OS - if not null, the parser will print information about the
 335     /// table as it parses it.
 336     LineTable
 337     parseNext(
 338         function_ref<void(Error)> RecoverableErrorCallback,
 339         function_ref<void(Error)> UnrecoverableErrorCallback,
 340         raw_ostream *OS = nullptr);
 341
 342     /// Skip the current line table and go to the following line table (if
 343     /// present) immediately.
 344     ///
 345     /// \param ErrorCallback - report any prologue parsing issues via this
 346     /// callback.
 347     void skip(function_ref<void(Error)> ErrorCallback);
 348
 349     /// Indicates if the parser has parsed as much as possible.
 350     ///
 351     /// \note Certain problems with the line table structure might mean that
 352     /// parsing stops before the end of the section is reached.
 353     bool done() const { return Done; }
 354
 355     /// Get the offset the parser has reached.
 356     uint64_t getOffset() const { return Offset; }
 357
 358   private:
 359     DWARFUnit *prepareToParse(uint64_t Offset);
 360     void moveToNextTable(uint64_t OldOffset, const Prologue &P);
 361
 362     LineToUnitMap LineToUnit;
 363
 364     DWARFDataExtractor &DebugLineData;
 365     const DWARFContext &Context;
 366     uint64_t Offset = 0;
 367     bool Done = false;
 368   };
 369
 370 private:
 371   struct ParsingState {
 372     ParsingState(struct LineTable *LT);
 373
 374     void resetRowAndSequence();
 375     void appendRowToMatrix();
 376
 377     /// Line table we're currently parsing.
 378     struct LineTable *LineTable;
 379     struct Row Row;
 380     struct Sequence Sequence;
 381   };
 382
 383   using LineTableMapTy = std::map<uint64_t, LineTable>;
 384   using LineTableIter = LineTableMapTy::iterator;
 385   using LineTableConstIter = LineTableMapTy::const_iterator;
 386
 387   LineTableMapTy LineTableMap;
 388 };
 389
 390 } // end namespace llvm
 391
 392 #endif // LLVM_DEBUGINFO_DWARFDEBUGLINE_H