1//===-- DWARFDebugLine.h ----------------------------------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef LLVM_LIB_DEBUGINFO_DWARFDEBUGLINE_H
11#define LLVM_LIB_DEBUGINFO_DWARFDEBUGLINE_H
12
13#include "llvm/DebugInfo/DIContext.h"
14#include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
15#include "llvm/Support/DataExtractor.h"
16#include <map>
17#include <string>
18#include <vector>
19
20namespace llvm {
21
22class raw_ostream;
23
24class DWARFDebugLine {
25public:
26  DWARFDebugLine(const RelocAddrMap* LineInfoRelocMap) : RelocMap(LineInfoRelocMap) {}
27  struct FileNameEntry {
28    FileNameEntry() : Name(nullptr), DirIdx(0), ModTime(0), Length(0) {}
29
30    const char *Name;
31    uint64_t DirIdx;
32    uint64_t ModTime;
33    uint64_t Length;
34  };
35
36  struct Prologue {
37    Prologue();
38
39    // The size in bytes of the statement information for this compilation unit
40    // (not including the total_length field itself).
41    uint64_t TotalLength;
42    // Version identifier for the statement information format.
43    uint16_t Version;
44    // The number of bytes following the prologue_length field to the beginning
45    // of the first byte of the statement program itself.
46    uint64_t PrologueLength;
47    // The size in bytes of the smallest target machine instruction. Statement
48    // program opcodes that alter the address register first multiply their
49    // operands by this value.
50    uint8_t MinInstLength;
51    // The maximum number of individual operations that may be encoded in an
52    // instruction.
53    uint8_t MaxOpsPerInst;
54    // The initial value of theis_stmtregister.
55    uint8_t DefaultIsStmt;
56    // This parameter affects the meaning of the special opcodes. See below.
57    int8_t LineBase;
58    // This parameter affects the meaning of the special opcodes. See below.
59    uint8_t LineRange;
60    // The number assigned to the first special opcode.
61    uint8_t OpcodeBase;
62    std::vector<uint8_t> StandardOpcodeLengths;
63    std::vector<const char*> IncludeDirectories;
64    std::vector<FileNameEntry> FileNames;
65
66    bool IsDWARF64;
67    uint32_t sizeofTotalLength() const {
68      return IsDWARF64 ? 12 : 4;
69    }
70    uint32_t sizeofPrologueLength() const {
71      return IsDWARF64 ? 8 : 4;
72    }
73
74    // Length of the prologue in bytes.
75    uint32_t getLength() const {
76      return PrologueLength + sizeofTotalLength() + sizeof(Version) +
77             sizeofPrologueLength();
78    }
79    // Length of the line table data in bytes (not including the prologue).
80    uint32_t getStatementTableLength() const {
81      return TotalLength + sizeofTotalLength() - getLength();
82    }
83    int32_t getMaxLineIncrementForSpecialOpcode() const {
84      return LineBase + (int8_t)LineRange - 1;
85    }
86
87    void clear();
88    void dump(raw_ostream &OS) const;
89    bool parse(DataExtractor debug_line_data, uint32_t *offset_ptr);
90  };
91
92  // Standard .debug_line state machine structure.
93  struct Row {
94    explicit Row(bool default_is_stmt = false);
95
96    /// Called after a row is appended to the matrix.
97    void postAppend();
98    void reset(bool default_is_stmt);
99    void dump(raw_ostream &OS) const;
100
101    static bool orderByAddress(const Row& LHS, const Row& RHS) {
102      return LHS.Address < RHS.Address;
103    }
104
105    // The program-counter value corresponding to a machine instruction
106    // generated by the compiler.
107    uint64_t Address;
108    // An unsigned integer indicating a source line number. Lines are numbered
109    // beginning at 1. The compiler may emit the value 0 in cases where an
110    // instruction cannot be attributed to any source line.
111    uint32_t Line;
112    // An unsigned integer indicating a column number within a source line.
113    // Columns are numbered beginning at 1. The value 0 is reserved to indicate
114    // that a statement begins at the 'left edge' of the line.
115    uint16_t Column;
116    // An unsigned integer indicating the identity of the source file
117    // corresponding to a machine instruction.
118    uint16_t File;
119    // An unsigned integer whose value encodes the applicable instruction set
120    // architecture for the current instruction.
121    uint8_t Isa;
122    // An unsigned integer representing the DWARF path discriminator value
123    // for this location.
124    uint32_t Discriminator;
125    // A boolean indicating that the current instruction is the beginning of a
126    // statement.
127    uint8_t IsStmt:1,
128            // A boolean indicating that the current instruction is the
129            // beginning of a basic block.
130            BasicBlock:1,
131            // A boolean indicating that the current address is that of the
132            // first byte after the end of a sequence of target machine
133            // instructions.
134            EndSequence:1,
135            // A boolean indicating that the current address is one (of possibly
136            // many) where execution should be suspended for an entry breakpoint
137            // of a function.
138            PrologueEnd:1,
139            // A boolean indicating that the current address is one (of possibly
140            // many) where execution should be suspended for an exit breakpoint
141            // of a function.
142            EpilogueBegin:1;
143  };
144
145  // Represents a series of contiguous machine instructions. Line table for each
146  // compilation unit may consist of multiple sequences, which are not
147  // guaranteed to be in the order of ascending instruction address.
148  struct Sequence {
149    // Sequence describes instructions at address range [LowPC, HighPC)
150    // and is described by line table rows [FirstRowIndex, LastRowIndex).
151    uint64_t LowPC;
152    uint64_t HighPC;
153    unsigned FirstRowIndex;
154    unsigned LastRowIndex;
155    bool Empty;
156
157    Sequence();
158    void reset();
159
160    static bool orderByLowPC(const Sequence& LHS, const Sequence& RHS) {
161      return LHS.LowPC < RHS.LowPC;
162    }
163    bool isValid() const {
164      return !Empty && (LowPC < HighPC) && (FirstRowIndex < LastRowIndex);
165    }
166    bool containsPC(uint64_t pc) const {
167      return (LowPC <= pc && pc < HighPC);
168    }
169  };
170
171  struct LineTable {
172    LineTable();
173
174    // Represents an invalid row
175    const uint32_t UnknownRowIndex = UINT32_MAX;
176
177    void appendRow(const DWARFDebugLine::Row &R) {
178      Rows.push_back(R);
179    }
180    void appendSequence(const DWARFDebugLine::Sequence &S) {
181      Sequences.push_back(S);
182    }
183
184    // Returns the index of the row with file/line info for a given address,
185    // or UnknownRowIndex if there is no such row.
186    uint32_t lookupAddress(uint64_t address) const;
187
188    bool lookupAddressRange(uint64_t address, uint64_t size,
189                            std::vector<uint32_t> &result) const;
190
191    // Extracts filename by its index in filename table in prologue.
192    // Returns true on success.
193    bool getFileNameByIndex(uint64_t FileIndex, const char *CompDir,
194                            DILineInfoSpecifier::FileLineInfoKind Kind,
195                            std::string &Result) const;
196
197    // Fills the Result argument with the file and line information
198    // corresponding to Address. Returns true on success.
199    bool getFileLineInfoForAddress(uint64_t Address, const char *CompDir,
200                                   DILineInfoSpecifier::FileLineInfoKind Kind,
201                                   DILineInfo &Result) const;
202
203    void dump(raw_ostream &OS) const;
204    void clear();
205
206    /// Parse prologue and all rows.
207    bool parse(DataExtractor debug_line_data, const RelocAddrMap *RMap,
208               uint32_t *offset_ptr);
209
210    struct Prologue Prologue;
211    typedef std::vector<Row> RowVector;
212    typedef RowVector::const_iterator RowIter;
213    typedef std::vector<Sequence> SequenceVector;
214    typedef SequenceVector::const_iterator SequenceIter;
215    RowVector Rows;
216    SequenceVector Sequences;
217
218  private:
219    uint32_t findRowInSeq(const DWARFDebugLine::Sequence &seq,
220                          uint64_t address) const;
221  };
222
223  const LineTable *getLineTable(uint32_t offset) const;
224  const LineTable *getOrParseLineTable(DataExtractor debug_line_data,
225                                       uint32_t offset);
226
227private:
228  struct ParsingState {
229    ParsingState(struct LineTable *LT);
230
231    void resetRowAndSequence();
232    void appendRowToMatrix(uint32_t offset);
233
234    // Line table we're currently parsing.
235    struct LineTable *LineTable;
236    // The row number that starts at zero for the prologue, and increases for
237    // each row added to the matrix.
238    unsigned RowNumber;
239    struct Row Row;
240    struct Sequence Sequence;
241  };
242
243  typedef std::map<uint32_t, LineTable> LineTableMapTy;
244  typedef LineTableMapTy::iterator LineTableIter;
245  typedef LineTableMapTy::const_iterator LineTableConstIter;
246
247  const RelocAddrMap *RelocMap;
248  LineTableMapTy LineTableMap;
249};
250}
251
252#endif
253