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//===- DWARFDebugLine.h -----------------------------------------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#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 <cstdint>
#include <map>
#include <string>
#include <vector>
namespace llvm {
class DWARFUnit;
class raw_ostream;
class DWARFDebugLine {
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 {
/// 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.
uint32_t getLength() const {
return PrologueLength + sizeofTotalLength() + sizeof(getVersion()) +
/// Length of the line table data in bytes (not including the prologue).
uint32_t getStatementTableLength() const {
return TotalLength + sizeofTotalLength() - getLength();
int32_t getMaxLineIncrementForSpecialOpcode() const {
return LineBase + (int8_t)LineRange - 1;
void clear();
void dump(raw_ostream &OS, DIDumpOptions DumpOptions) const;
Error parse(const DWARFDataExtractor &DebugLineData, uint32_t *OffsetPtr,
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);
static bool orderByAddress(const Row &LHS, const Row &RHS) {
return LHS.Address < RHS.Address;
/// The program-counter value corresponding to a machine instruction
/// generated by the compiler.
uint64_t 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 describes instructions at address range [LowPC, HighPC)
/// and is described by line table rows [FirstRowIndex, LastRowIndex).
uint64_t LowPC;
uint64_t HighPC;
unsigned FirstRowIndex;
unsigned LastRowIndex;
bool Empty;
void reset();
static bool orderByLowPC(const Sequence &LHS, const Sequence &RHS) {
return LHS.LowPC < RHS.LowPC;
bool isValid() const {
return !Empty && (LowPC < HighPC) && (FirstRowIndex < LastRowIndex);
bool containsPC(uint64_t PC) const { return (LowPC <= PC && PC < HighPC); }
struct 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) {
/// 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(uint64_t Address) const;
bool lookupAddressRange(uint64_t Address, uint64_t Size,
std::vector<uint32_t> &Result) const;
bool hasFileAtIndex(uint64_t FileIndex) const;
/// Extracts filename by its index in filename table in prologue.
/// Returns true on success.
bool getFileNameByIndex(uint64_t FileIndex, const char *CompDir,
DILineInfoSpecifier::FileLineInfoKind Kind,
std::string &Result) const;
/// Fills the Result argument with the file and line information
/// corresponding to Address. Returns true on success.
bool getFileLineInfoForAddress(uint64_t 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, uint32_t *OffsetPtr,
const DWARFContext &Ctx, const DWARFUnit *U,
std::function<void(Error)> RecoverableErrorCallback,
raw_ostream *OS = nullptr);
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;
uint32_t findRowInSeq(const DWARFDebugLine::Sequence &Seq,
uint64_t Address) const;
getSourceByIndex(uint64_t FileIndex,
DILineInfoSpecifier::FileLineInfoKind Kind) const;
const LineTable *getLineTable(uint32_t Offset) const;
Expected<const LineTable *> getOrParseLineTable(
DWARFDataExtractor &DebugLineData, uint32_t Offset,
const DWARFContext &Ctx, const DWARFUnit *U,
std::function<void(Error)> RecoverableErrorCallback);
/// Helper to allow for parsing of an entire .debug_line section in sequence.
class SectionParser {
using cu_range = DWARFUnitVector::iterator_range;
using tu_range = DWARFUnitVector::iterator_range;
using LineToUnitMap = std::map<uint64_t, DWARFUnit *>;
SectionParser(DWARFDataExtractor &Data, const DWARFContext &C, cu_range CUs,
tu_range TUs);
/// Get the next line table from the section. Report any issues via the
/// callbacks.
/// \param RecoverableErrorCallback - any issues that don't prevent further
/// parsing of the table will be reported through this callback.
/// \param UnrecoverableErrorCallback - any issues that prevent further
/// parsing of the table will be reported through this callback.
/// \param OS - if not null, the parser will print information about the
/// table as it parses it.
function_ref<void(Error)> RecoverableErrorCallback,
function_ref<void(Error)> UnrecoverableErrorCallback,
raw_ostream *OS = nullptr);
/// Skip the current line table and go to the following line table (if
/// present) immediately.
/// \param ErrorCallback - report any prologue parsing issues via this
/// callback.
void skip(function_ref<void(Error)> ErrorCallback);
/// 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.
uint32_t getOffset() const { return Offset; }
DWARFUnit *prepareToParse(uint32_t Offset);
void moveToNextTable(uint32_t OldOffset, const Prologue &P);
LineToUnitMap LineToUnit;
DWARFDataExtractor &DebugLineData;
const DWARFContext &Context;
uint32_t Offset = 0;
bool Done = false;
struct ParsingState {
ParsingState(struct LineTable *LT);
void resetRowAndSequence();
void appendRowToMatrix(uint32_t Offset);
/// Line table we're currently parsing.
struct LineTable *LineTable;
/// The row number that starts at zero for the prologue, and increases for
/// each row added to the matrix.
unsigned RowNumber = 0;
struct Row Row;
struct Sequence Sequence;
using LineTableMapTy = std::map<uint32_t, LineTable>;
using LineTableIter = LineTableMapTy::iterator;
using LineTableConstIter = LineTableMapTy::const_iterator;
LineTableMapTy LineTableMap;
} // end namespace llvm