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/DWARF/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     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.
getLengthPrologue67     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).
getStatementTableLengthPrologue72     uint32_t getStatementTableLength() const {
73       return TotalLength + sizeof(TotalLength) - getLength();
74     }
getMaxLineIncrementForSpecialOpcodePrologue75     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 
orderByAddressRow93     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 
orderByLowPCSequence152     static bool orderByLowPC(const Sequence& LHS, const Sequence& RHS) {
153       return LHS.LowPC < RHS.LowPC;
154     }
isValidSequence155     bool isValid() const {
156       return !Empty && (LowPC < HighPC) && (FirstRowIndex < LastRowIndex);
157     }
containsPCSequence158     bool containsPC(uint64_t pc) const {
159       return (LowPC <= pc && pc < HighPC);
160     }
161   };
162 
163   struct LineTable {
164     LineTable();
165 
appendRowLineTable166     void appendRow(const DWARFDebugLine::Row &R) {
167       Rows.push_back(R);
168     }
appendSequenceLineTable169     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, const char *CompDir,
183                             DILineInfoSpecifier::FileLineInfoKind Kind,
184                             std::string &Result) const;
185 
186     // Fills the Result argument with the file and line information
187     // corresponding to Address. Returns true on success.
188     bool getFileLineInfoForAddress(uint64_t Address, const char *CompDir,
189                                    DILineInfoSpecifier::FileLineInfoKind Kind,
190                                    DILineInfo &Result) const;
191 
192     void dump(raw_ostream &OS) const;
193     void clear();
194 
195     /// Parse prologue and all rows.
196     bool parse(DataExtractor debug_line_data, const RelocAddrMap *RMap,
197                uint32_t *offset_ptr);
198 
199     struct Prologue Prologue;
200     typedef std::vector<Row> RowVector;
201     typedef RowVector::const_iterator RowIter;
202     typedef std::vector<Sequence> SequenceVector;
203     typedef SequenceVector::const_iterator SequenceIter;
204     RowVector Rows;
205     SequenceVector Sequences;
206   };
207 
208   const LineTable *getLineTable(uint32_t offset) const;
209   const LineTable *getOrParseLineTable(DataExtractor debug_line_data,
210                                        uint32_t offset);
211 
212 private:
213   struct ParsingState {
214     ParsingState(struct LineTable *LT);
215 
216     void resetRowAndSequence();
217     void appendRowToMatrix(uint32_t offset);
218 
219     // Line table we're currently parsing.
220     struct LineTable *LineTable;
221     // The row number that starts at zero for the prologue, and increases for
222     // each row added to the matrix.
223     unsigned RowNumber;
224     struct Row Row;
225     struct Sequence Sequence;
226   };
227 
228   typedef std::map<uint32_t, LineTable> LineTableMapTy;
229   typedef LineTableMapTy::iterator LineTableIter;
230   typedef LineTableMapTy::const_iterator LineTableConstIter;
231 
232   const RelocAddrMap *RelocMap;
233   LineTableMapTy LineTableMap;
234 };
235 
236 }
237 
238 #endif
239