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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 
20 namespace llvm {
21 
22 class raw_ostream;
23 
24 class DWARFDebugLine {
25 public:
DWARFDebugLine(const RelocAddrMap * LineInfoRelocMap)26   DWARFDebugLine(const RelocAddrMap* LineInfoRelocMap) : RelocMap(LineInfoRelocMap) {}
27   struct FileNameEntry {
FileNameEntryFileNameEntry28     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;
sizeofTotalLengthPrologue67     uint32_t sizeofTotalLength() const {
68       return IsDWARF64 ? 12 : 4;
69     }
sizeofPrologueLengthPrologue70     uint32_t sizeofPrologueLength() const {
71       return IsDWARF64 ? 8 : 4;
72     }
73 
74     // Length of the prologue in bytes.
getLengthPrologue75     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).
getStatementTableLengthPrologue80     uint32_t getStatementTableLength() const {
81       return TotalLength + sizeofTotalLength() - getLength();
82     }
getMaxLineIncrementForSpecialOpcodePrologue83     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 
orderByAddressRow101     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 
orderByLowPCSequence160     static bool orderByLowPC(const Sequence& LHS, const Sequence& RHS) {
161       return LHS.LowPC < RHS.LowPC;
162     }
isValidSequence163     bool isValid() const {
164       return !Empty && (LowPC < HighPC) && (FirstRowIndex < LastRowIndex);
165     }
containsPCSequence166     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 
appendRowLineTable177     void appendRow(const DWARFDebugLine::Row &R) {
178       Rows.push_back(R);
179     }
appendSequenceLineTable180     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 
227 private:
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