MCDwarf.h revision 14a708b98e7192c3038b984dfbd0a7e0d532867d 
1//===- MCDwarf.h - Machine Code Dwarf support -------------------*- 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// This file contains the declaration of the MCDwarfFile to support the dwarf
11// .file directive and the .loc directive.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_MC_MCDWARF_H
16#define LLVM_MC_MCDWARF_H
17
18#include "llvm/ADT/StringRef.h"
19#include "llvm/Support/raw_ostream.h"
20#include "llvm/Support/Dwarf.h"
21#include "llvm/Support/Compiler.h"
22#include <vector>
23
24namespace llvm {
25  class MCContext;
26  class MCObjectWriter;
27  class MCSection;
28  class MCStreamer;
29  class MCSymbol;
30  class SourceMgr;
31  class SMLoc;
32
33  /// MCDwarfFile - Instances of this class represent the name of the dwarf
34  /// .file directive and its associated dwarf file number in the MC file,
35  /// and MCDwarfFile's are created and unique'd by the MCContext class where
36  /// the file number for each is its index into the vector of DwarfFiles (note
37  /// index 0 is not used and not a valid dwarf file number).
38  class MCDwarfFile {
39    // Name - the base name of the file without its directory path.
40    // The StringRef references memory allocated in the MCContext.
41    StringRef Name;
42
43    // DirIndex - the index into the list of directory names for this file name.
44    unsigned DirIndex;
45
46  private:  // MCContext creates and uniques these.
47    friend class MCContext;
48    MCDwarfFile(StringRef name, unsigned dirIndex)
49      : Name(name), DirIndex(dirIndex) {}
50
51    MCDwarfFile(const MCDwarfFile&) LLVM_DELETED_FUNCTION;
52    void operator=(const MCDwarfFile&) LLVM_DELETED_FUNCTION;
53  public:
54    /// getName - Get the base name of this MCDwarfFile.
55    StringRef getName() const { return Name; }
56
57    /// getDirIndex - Get the dirIndex of this MCDwarfFile.
58    unsigned getDirIndex() const { return DirIndex; }
59
60
61    /// print - Print the value to the stream \p OS.
62    void print(raw_ostream &OS) const;
63
64    /// dump - Print the value to stderr.
65    void dump() const;
66  };
67
68  inline raw_ostream &operator<<(raw_ostream &OS, const MCDwarfFile &DwarfFile){
69    DwarfFile.print(OS);
70    return OS;
71  }
72
73  /// MCDwarfLoc - Instances of this class represent the information from a
74  /// dwarf .loc directive.
75  class MCDwarfLoc {
76    // FileNum - the file number.
77    unsigned FileNum;
78    // Line - the line number.
79    unsigned Line;
80    // Column - the column position.
81    unsigned Column;
82    // Flags (see #define's below)
83    unsigned Flags;
84    // Isa
85    unsigned Isa;
86    // Discriminator
87    unsigned Discriminator;
88
89// Flag that indicates the initial value of the is_stmt_start flag.
90#define DWARF2_LINE_DEFAULT_IS_STMT     1
91
92#define DWARF2_FLAG_IS_STMT        (1 << 0)
93#define DWARF2_FLAG_BASIC_BLOCK    (1 << 1)
94#define DWARF2_FLAG_PROLOGUE_END   (1 << 2)
95#define DWARF2_FLAG_EPILOGUE_BEGIN (1 << 3)
96
97  private:  // MCContext manages these
98    friend class MCContext;
99    friend class MCLineEntry;
100    MCDwarfLoc(unsigned fileNum, unsigned line, unsigned column, unsigned flags,
101               unsigned isa, unsigned discriminator)
102      : FileNum(fileNum), Line(line), Column(column), Flags(flags), Isa(isa),
103        Discriminator(discriminator) {}
104
105    // Allow the default copy constructor and assignment operator to be used
106    // for an MCDwarfLoc object.
107
108  public:
109    /// getFileNum - Get the FileNum of this MCDwarfLoc.
110    unsigned getFileNum() const { return FileNum; }
111
112    /// getLine - Get the Line of this MCDwarfLoc.
113    unsigned getLine() const { return Line; }
114
115    /// getColumn - Get the Column of this MCDwarfLoc.
116    unsigned getColumn() const { return Column; }
117
118    /// getFlags - Get the Flags of this MCDwarfLoc.
119    unsigned getFlags() const { return Flags; }
120
121    /// getIsa - Get the Isa of this MCDwarfLoc.
122    unsigned getIsa() const { return Isa; }
123
124    /// getDiscriminator - Get the Discriminator of this MCDwarfLoc.
125    unsigned getDiscriminator() const { return Discriminator; }
126
127    /// setFileNum - Set the FileNum of this MCDwarfLoc.
128    void setFileNum(unsigned fileNum) { FileNum = fileNum; }
129
130    /// setLine - Set the Line of this MCDwarfLoc.
131    void setLine(unsigned line) { Line = line; }
132
133    /// setColumn - Set the Column of this MCDwarfLoc.
134    void setColumn(unsigned column) { Column = column; }
135
136    /// setFlags - Set the Flags of this MCDwarfLoc.
137    void setFlags(unsigned flags) { Flags = flags; }
138
139    /// setIsa - Set the Isa of this MCDwarfLoc.
140    void setIsa(unsigned isa) { Isa = isa; }
141
142    /// setDiscriminator - Set the Discriminator of this MCDwarfLoc.
143    void setDiscriminator(unsigned discriminator) {
144      Discriminator = discriminator;
145    }
146  };
147
148  /// MCLineEntry - Instances of this class represent the line information for
149  /// the dwarf line table entries.  Which is created after a machine
150  /// instruction is assembled and uses an address from a temporary label
151  /// created at the current address in the current section and the info from
152  /// the last .loc directive seen as stored in the context.
153  class MCLineEntry : public MCDwarfLoc {
154    MCSymbol *Label;
155
156  private:
157    // Allow the default copy constructor and assignment operator to be used
158    // for an MCLineEntry object.
159
160  public:
161    // Constructor to create an MCLineEntry given a symbol and the dwarf loc.
162    MCLineEntry(MCSymbol *label, const MCDwarfLoc loc) : MCDwarfLoc(loc),
163                Label(label) {}
164
165    MCSymbol *getLabel() const { return Label; }
166
167    // This is called when an instruction is assembled into the specified
168    // section and if there is information from the last .loc directive that
169    // has yet to have a line entry made for it is made.
170    static void Make(MCStreamer *MCOS, const MCSection *Section);
171  };
172
173  /// MCLineSection - Instances of this class represent the line information
174  /// for a section where machine instructions have been assembled after seeing
175  /// .loc directives.  This is the information used to build the dwarf line
176  /// table for a section.
177  class MCLineSection {
178
179  private:
180    MCLineSection(const MCLineSection&) LLVM_DELETED_FUNCTION;
181    void operator=(const MCLineSection&) LLVM_DELETED_FUNCTION;
182
183  public:
184    // Constructor to create an MCLineSection with an empty MCLineEntries
185    // vector.
186    MCLineSection() {}
187
188    // addLineEntry - adds an entry to this MCLineSection's line entries
189    void addLineEntry(const MCLineEntry &LineEntry) {
190      MCLineEntries.push_back(LineEntry);
191    }
192
193    typedef std::vector<MCLineEntry> MCLineEntryCollection;
194    typedef MCLineEntryCollection::iterator iterator;
195    typedef MCLineEntryCollection::const_iterator const_iterator;
196
197  private:
198    MCLineEntryCollection MCLineEntries;
199
200  public:
201    const MCLineEntryCollection *getMCLineEntries() const {
202      return &MCLineEntries;
203    }
204  };
205
206  class MCDwarfFileTable {
207  public:
208    //
209    // This emits the Dwarf file and the line tables.
210    //
211    static const MCSymbol *Emit(MCStreamer *MCOS);
212  };
213
214  class MCDwarfLineAddr {
215  public:
216    /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
217    static void Encode(int64_t LineDelta, uint64_t AddrDelta, raw_ostream &OS);
218
219    /// Utility function to emit the encoding to a streamer.
220    static void Emit(MCStreamer *MCOS,
221                     int64_t LineDelta,uint64_t AddrDelta);
222
223    /// Utility function to write the encoding to an object writer.
224    static void Write(MCObjectWriter *OW,
225                      int64_t LineDelta, uint64_t AddrDelta);
226  };
227
228  class MCGenDwarfInfo {
229  public:
230    //
231    // When generating dwarf for assembly source files this emits the Dwarf
232    // sections.
233    //
234    static void Emit(MCStreamer *MCOS, const MCSymbol *LineSectionSymbol);
235  };
236
237  // When generating dwarf for assembly source files this is the info that is
238  // needed to be gathered for each symbol that will have a dwarf label.
239  class MCGenDwarfLabelEntry {
240  private:
241    // Name of the symbol without a leading underbar, if any.
242    StringRef Name;
243    // The dwarf file number this symbol is in.
244    unsigned FileNumber;
245    // The line number this symbol is at.
246    unsigned LineNumber;
247    // The low_pc for the dwarf label is taken from this symbol.
248    MCSymbol *Label;
249
250  public:
251    MCGenDwarfLabelEntry(StringRef name, unsigned fileNumber,
252                         unsigned lineNumber, MCSymbol *label) :
253      Name(name), FileNumber(fileNumber), LineNumber(lineNumber), Label(label){}
254
255    StringRef getName() const { return Name; }
256    unsigned getFileNumber() const { return FileNumber; }
257    unsigned getLineNumber() const { return LineNumber; }
258    MCSymbol *getLabel() const { return Label; }
259
260    // This is called when label is created when we are generating dwarf for
261    // assembly source files.
262    static void Make(MCSymbol *Symbol, MCStreamer *MCOS, SourceMgr &SrcMgr,
263                     SMLoc &Loc);
264  };
265
266  class MCCFIInstruction {
267  public:
268    enum OpType { OpSameValue, OpRememberState, OpRestoreState, OpOffset,
269                  OpDefCfaRegister, OpDefCfaOffset, OpDefCfa, OpRelOffset,
270                  OpAdjustCfaOffset, OpEscape, OpRestore, OpUndefined };
271  private:
272    OpType Operation;
273    MCSymbol *Label;
274    unsigned Register;
275    int Offset;
276    std::vector<char> Values;
277
278    MCCFIInstruction(OpType Op, MCSymbol *L, unsigned R,
279                     int O, StringRef V) :
280      Operation(Op), Label(L), Register(R), Offset(O),
281      Values(V.begin(), V.end()) {
282    }
283
284  public:
285    static MCCFIInstruction
286    createOffset(MCSymbol *L, unsigned Register, int Offset) {
287      return MCCFIInstruction(OpOffset, L, Register, Offset, "");
288    }
289
290    static MCCFIInstruction
291    createDefCfaRegister(MCSymbol *L, unsigned Register) {
292      return MCCFIInstruction(OpDefCfaRegister, L, Register, 0, "");
293    }
294
295    static MCCFIInstruction createDefCfaOffset(MCSymbol *L, int Offset) {
296      return MCCFIInstruction(OpDefCfaOffset, L, 0, -Offset, "");
297    }
298
299    static MCCFIInstruction
300    createDefCfa(MCSymbol *L, unsigned Register, int Offset) {
301      return MCCFIInstruction(OpDefCfa, L, Register, -Offset, "");
302    }
303
304    static MCCFIInstruction createUndefined(MCSymbol *L, unsigned Register) {
305      return MCCFIInstruction(OpUndefined, L, Register, 0, "");
306    }
307
308    static MCCFIInstruction createRestore(MCSymbol *L, unsigned Register) {
309      return MCCFIInstruction(OpRestore, L, Register, 0, "");
310    }
311
312    static MCCFIInstruction createSameValue(MCSymbol *L, unsigned Register) {
313      return MCCFIInstruction(OpSameValue, L, Register, 0, "");
314    }
315
316    static MCCFIInstruction createRestoreState(MCSymbol *L) {
317      return MCCFIInstruction(OpRestoreState, L, 0, 0, "");
318    }
319
320    static MCCFIInstruction createRememberState(MCSymbol *L) {
321      return MCCFIInstruction(OpRememberState, L, 0, 0, "");
322    }
323
324    static MCCFIInstruction
325    createRelOffset(MCSymbol *L, unsigned Register, int Offset) {
326      return MCCFIInstruction(OpRelOffset, L, Register, Offset, "");
327    }
328
329    static MCCFIInstruction
330    createAdjustCfaOffset(MCSymbol *L, int Adjustment) {
331      return MCCFIInstruction(OpAdjustCfaOffset, L, 0, Adjustment, "");
332    }
333
334    static MCCFIInstruction createEscape(MCSymbol *L, StringRef Vals) {
335      return MCCFIInstruction(OpEscape, L, 0, 0, Vals);
336    }
337
338    OpType getOperation() const { return Operation; }
339    MCSymbol *getLabel() const { return Label; }
340
341    unsigned getRegister() const {
342      assert(Operation == OpDefCfa || Operation == OpOffset ||
343             Operation == OpRestore || Operation == OpUndefined ||
344             Operation == OpSameValue || Operation == OpDefCfaRegister ||
345             Operation == OpRelOffset);
346      return Register;
347    }
348
349    int getOffset() const {
350      assert(Operation == OpDefCfa || Operation == OpOffset ||
351             Operation == OpRelOffset || Operation == OpDefCfaOffset ||
352             Operation == OpAdjustCfaOffset);
353      return Offset;
354    }
355
356    const StringRef getValues() const {
357      assert(Operation == OpEscape);
358      return StringRef(&Values[0], Values.size());
359    }
360  };
361
362  struct MCDwarfFrameInfo {
363    MCDwarfFrameInfo() : Begin(0), End(0), Personality(0), Lsda(0),
364                         Function(0), Instructions(), PersonalityEncoding(),
365                         LsdaEncoding(0), CompactUnwindEncoding(0),
366                         IsSignalFrame(false) {}
367    MCSymbol *Begin;
368    MCSymbol *End;
369    const MCSymbol *Personality;
370    const MCSymbol *Lsda;
371    const MCSymbol *Function;
372    std::vector<MCCFIInstruction> Instructions;
373    unsigned PersonalityEncoding;
374    unsigned LsdaEncoding;
375    uint32_t CompactUnwindEncoding;
376    bool IsSignalFrame;
377  };
378
379  class MCDwarfFrameEmitter {
380  public:
381    //
382    // This emits the frame info section.
383    //
384    static void Emit(MCStreamer &streamer, bool usingCFI,
385                     bool isEH);
386    static void EmitAdvanceLoc(MCStreamer &Streamer, uint64_t AddrDelta);
387    static void EncodeAdvanceLoc(uint64_t AddrDelta, raw_ostream &OS);
388  };
389} // end namespace llvm
390
391#endif
392