DWARFDebugLine.h revision dce4a407a24b04eebc6a376f8e62b41aaa7b071f 
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_DEBUGINFO_DWARFDEBUGLINE_H
11#define LLVM_DEBUGINFO_DWARFDEBUGLINE_H
12
13#include "DWARFRelocMap.h"
14#include "llvm/DebugInfo/DIContext.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    uint32_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    uint32_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    // Length of the prologue in bytes.
67    uint32_t getLength() const {
68      return PrologueLength + sizeof(TotalLength) + sizeof(Version) +
69             sizeof(PrologueLength);
70    }
71    // Length of the line table data in bytes (not including the prologue).
72    uint32_t getStatementTableLength() const {
73      return TotalLength + sizeof(TotalLength) - getLength();
74    }
75    int32_t getMaxLineIncrementForSpecialOpcode() const {
76      return LineBase + (int8_t)LineRange - 1;
77    }
78
79    void clear();
80    void dump(raw_ostream &OS) const;
81    bool parse(DataExtractor debug_line_data, uint32_t *offset_ptr);
82  };
83
84  // Standard .debug_line state machine structure.
85  struct Row {
86    explicit Row(bool default_is_stmt = false);
87
88    /// Called after a row is appended to the matrix.
89    void postAppend();
90    void reset(bool default_is_stmt);
91    void dump(raw_ostream &OS) const;
92
93    static bool orderByAddress(const Row& LHS, const Row& RHS) {
94      return LHS.Address < RHS.Address;
95    }
96
97    // The program-counter value corresponding to a machine instruction
98    // generated by the compiler.
99    uint64_t Address;
100    // An unsigned integer indicating a source line number. Lines are numbered
101    // beginning at 1. The compiler may emit the value 0 in cases where an
102    // instruction cannot be attributed to any source line.
103    uint32_t Line;
104    // An unsigned integer indicating a column number within a source line.
105    // Columns are numbered beginning at 1. The value 0 is reserved to indicate
106    // that a statement begins at the 'left edge' of the line.
107    uint16_t Column;
108    // An unsigned integer indicating the identity of the source file
109    // corresponding to a machine instruction.
110    uint16_t File;
111    // An unsigned integer whose value encodes the applicable instruction set
112    // architecture for the current instruction.
113    uint8_t Isa;
114    // An unsigned integer representing the DWARF path discriminator value
115    // for this location.
116    uint32_t Discriminator;
117    // A boolean indicating that the current instruction is the beginning of a
118    // statement.
119    uint8_t IsStmt:1,
120            // A boolean indicating that the current instruction is the
121            // beginning of a basic block.
122            BasicBlock:1,
123            // A boolean indicating that the current address is that of the
124            // first byte after the end of a sequence of target machine
125            // instructions.
126            EndSequence:1,
127            // A boolean indicating that the current address is one (of possibly
128            // many) where execution should be suspended for an entry breakpoint
129            // of a function.
130            PrologueEnd:1,
131            // A boolean indicating that the current address is one (of possibly
132            // many) where execution should be suspended for an exit breakpoint
133            // of a function.
134            EpilogueBegin:1;
135  };
136
137  // Represents a series of contiguous machine instructions. Line table for each
138  // compilation unit may consist of multiple sequences, which are not
139  // guaranteed to be in the order of ascending instruction address.
140  struct Sequence {
141    // Sequence describes instructions at address range [LowPC, HighPC)
142    // and is described by line table rows [FirstRowIndex, LastRowIndex).
143    uint64_t LowPC;
144    uint64_t HighPC;
145    unsigned FirstRowIndex;
146    unsigned LastRowIndex;
147    bool Empty;
148
149    Sequence();
150    void reset();
151
152    static bool orderByLowPC(const Sequence& LHS, const Sequence& RHS) {
153      return LHS.LowPC < RHS.LowPC;
154    }
155    bool isValid() const {
156      return !Empty && (LowPC < HighPC) && (FirstRowIndex < LastRowIndex);
157    }
158    bool containsPC(uint64_t pc) const {
159      return (LowPC <= pc && pc < HighPC);
160    }
161  };
162
163  struct LineTable {
164    LineTable();
165
166    void appendRow(const DWARFDebugLine::Row &R) {
167      Rows.push_back(R);
168    }
169    void appendSequence(const DWARFDebugLine::Sequence &S) {
170      Sequences.push_back(S);
171    }
172
173    // Returns the index of the row with file/line info for a given address,
174    // or -1 if there is no such row.
175    uint32_t lookupAddress(uint64_t address) const;
176
177    bool lookupAddressRange(uint64_t address, uint64_t size,
178                            std::vector<uint32_t> &result) const;
179
180    // Extracts filename by its index in filename table in prologue.
181    // Returns true on success.
182    bool getFileNameByIndex(uint64_t FileIndex,
183                            DILineInfoSpecifier::FileLineInfoKind Kind,
184                            std::string &Result) const;
185
186    void dump(raw_ostream &OS) const;
187    void clear();
188
189    /// Parse prologue and all rows.
190    bool parse(DataExtractor debug_line_data, const RelocAddrMap *RMap,
191               uint32_t *offset_ptr);
192
193    struct Prologue Prologue;
194    typedef std::vector<Row> RowVector;
195    typedef RowVector::const_iterator RowIter;
196    typedef std::vector<Sequence> SequenceVector;
197    typedef SequenceVector::const_iterator SequenceIter;
198    RowVector Rows;
199    SequenceVector Sequences;
200  };
201
202  const LineTable *getLineTable(uint32_t offset) const;
203  const LineTable *getOrParseLineTable(DataExtractor debug_line_data,
204                                       uint32_t offset);
205
206private:
207  struct ParsingState {
208    ParsingState(struct LineTable *LT);
209
210    void resetRowAndSequence();
211    void appendRowToMatrix(uint32_t offset);
212
213    // Line table we're currently parsing.
214    struct LineTable *LineTable;
215    // The row number that starts at zero for the prologue, and increases for
216    // each row added to the matrix.
217    unsigned RowNumber;
218    struct Row Row;
219    struct Sequence Sequence;
220  };
221
222  typedef std::map<uint32_t, LineTable> LineTableMapTy;
223  typedef LineTableMapTy::iterator LineTableIter;
224  typedef LineTableMapTy::const_iterator LineTableConstIter;
225
226  const RelocAddrMap *RelocMap;
227  LineTableMapTy LineTableMap;
228};
229
230}
231
232#endif
233