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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/Compiler.h"
20 #include "llvm/Support/Dwarf.h"
21 #include "llvm/Support/raw_ostream.h"
22 #include <map>
23 #include <vector>
24 
25 namespace llvm {
26   class MCContext;
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;
MCDwarfFile(StringRef name,unsigned dirIndex)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.
getName()55     StringRef getName() const { return Name; }
56 
57     /// getDirIndex - Get the dirIndex of this MCDwarfFile.
getDirIndex()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;
MCDwarfLoc(unsigned fileNum,unsigned line,unsigned column,unsigned flags,unsigned isa,unsigned discriminator)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.
getFileNum()110     unsigned getFileNum() const { return FileNum; }
111 
112     /// getLine - Get the Line of this MCDwarfLoc.
getLine()113     unsigned getLine() const { return Line; }
114 
115     /// getColumn - Get the Column of this MCDwarfLoc.
getColumn()116     unsigned getColumn() const { return Column; }
117 
118     /// getFlags - Get the Flags of this MCDwarfLoc.
getFlags()119     unsigned getFlags() const { return Flags; }
120 
121     /// getIsa - Get the Isa of this MCDwarfLoc.
getIsa()122     unsigned getIsa() const { return Isa; }
123 
124     /// getDiscriminator - Get the Discriminator of this MCDwarfLoc.
getDiscriminator()125     unsigned getDiscriminator() const { return Discriminator; }
126 
127     /// setFileNum - Set the FileNum of this MCDwarfLoc.
setFileNum(unsigned fileNum)128     void setFileNum(unsigned fileNum) { FileNum = fileNum; }
129 
130     /// setLine - Set the Line of this MCDwarfLoc.
setLine(unsigned line)131     void setLine(unsigned line) { Line = line; }
132 
133     /// setColumn - Set the Column of this MCDwarfLoc.
setColumn(unsigned column)134     void setColumn(unsigned column) { Column = column; }
135 
136     /// setFlags - Set the Flags of this MCDwarfLoc.
setFlags(unsigned flags)137     void setFlags(unsigned flags) { Flags = flags; }
138 
139     /// setIsa - Set the Isa of this MCDwarfLoc.
setIsa(unsigned isa)140     void setIsa(unsigned isa) { Isa = isa; }
141 
142     /// setDiscriminator - Set the Discriminator of this MCDwarfLoc.
setDiscriminator(unsigned discriminator)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.
MCLineEntry(MCSymbol * label,const MCDwarfLoc loc)162     MCLineEntry(MCSymbol *label, const MCDwarfLoc loc) : MCDwarfLoc(loc),
163                 Label(label) {}
164 
getLabel()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.
MCLineSection()186     MCLineSection() {}
187 
188     // addLineEntry - adds an entry to this MCLineSection's line entries
addLineEntry(const MCLineEntry & LineEntry,unsigned CUID)189     void addLineEntry(const MCLineEntry &LineEntry, unsigned CUID) {
190       MCLineDivisions[CUID].push_back(LineEntry);
191     }
192 
193     typedef std::vector<MCLineEntry> MCLineEntryCollection;
194     typedef MCLineEntryCollection::iterator iterator;
195     typedef MCLineEntryCollection::const_iterator const_iterator;
196     typedef std::map<unsigned, MCLineEntryCollection> MCLineDivisionMap;
197 
198   private:
199     // A collection of MCLineEntry for each Compile Unit ID.
200     MCLineDivisionMap MCLineDivisions;
201 
202   public:
203     // Returns whether MCLineSection contains entries for a given Compile
204     // Unit ID.
containEntriesForID(unsigned CUID)205     bool containEntriesForID(unsigned CUID) const {
206       return MCLineDivisions.count(CUID);
207     }
208     // Returns the collection of MCLineEntry for a given Compile Unit ID.
getMCLineEntries(unsigned CUID)209     const MCLineEntryCollection &getMCLineEntries(unsigned CUID) const {
210       MCLineDivisionMap::const_iterator CIter = MCLineDivisions.find(CUID);
211       assert(CIter != MCLineDivisions.end());
212       return CIter->second;
213     }
214   };
215 
216   class MCDwarfFileTable {
217   public:
218     //
219     // This emits the Dwarf file and the line tables for all Compile Units.
220     //
221     static const MCSymbol *Emit(MCStreamer *MCOS);
222     //
223     // This emits the Dwarf file and the line tables for a given Compile Unit.
224     //
225     static const MCSymbol *EmitCU(MCStreamer *MCOS, unsigned ID);
226   };
227 
228   class MCDwarfLineAddr {
229   public:
230     /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
231     static void Encode(MCContext &Context, int64_t LineDelta,
232                        uint64_t AddrDelta, raw_ostream &OS);
233 
234     /// Utility function to emit the encoding to a streamer.
235     static void Emit(MCStreamer *MCOS,
236                      int64_t LineDelta,uint64_t AddrDelta);
237   };
238 
239   class MCGenDwarfInfo {
240   public:
241     //
242     // When generating dwarf for assembly source files this emits the Dwarf
243     // sections.
244     //
245     static void Emit(MCStreamer *MCOS, const MCSymbol *LineSectionSymbol);
246   };
247 
248   // When generating dwarf for assembly source files this is the info that is
249   // needed to be gathered for each symbol that will have a dwarf label.
250   class MCGenDwarfLabelEntry {
251   private:
252     // Name of the symbol without a leading underbar, if any.
253     StringRef Name;
254     // The dwarf file number this symbol is in.
255     unsigned FileNumber;
256     // The line number this symbol is at.
257     unsigned LineNumber;
258     // The low_pc for the dwarf label is taken from this symbol.
259     MCSymbol *Label;
260 
261   public:
MCGenDwarfLabelEntry(StringRef name,unsigned fileNumber,unsigned lineNumber,MCSymbol * label)262     MCGenDwarfLabelEntry(StringRef name, unsigned fileNumber,
263                          unsigned lineNumber, MCSymbol *label) :
264       Name(name), FileNumber(fileNumber), LineNumber(lineNumber), Label(label){}
265 
getName()266     StringRef getName() const { return Name; }
getFileNumber()267     unsigned getFileNumber() const { return FileNumber; }
getLineNumber()268     unsigned getLineNumber() const { return LineNumber; }
getLabel()269     MCSymbol *getLabel() const { return Label; }
270 
271     // This is called when label is created when we are generating dwarf for
272     // assembly source files.
273     static void Make(MCSymbol *Symbol, MCStreamer *MCOS, SourceMgr &SrcMgr,
274                      SMLoc &Loc);
275   };
276 
277   class MCCFIInstruction {
278   public:
279     enum OpType { OpSameValue, OpRememberState, OpRestoreState, OpOffset,
280                   OpDefCfaRegister, OpDefCfaOffset, OpDefCfa, OpRelOffset,
281                   OpAdjustCfaOffset, OpEscape, OpRestore, OpUndefined,
282                   OpRegister };
283   private:
284     OpType Operation;
285     MCSymbol *Label;
286     unsigned Register;
287     union {
288       int Offset;
289       unsigned Register2;
290     };
291     std::vector<char> Values;
292 
MCCFIInstruction(OpType Op,MCSymbol * L,unsigned R,int O,StringRef V)293     MCCFIInstruction(OpType Op, MCSymbol *L, unsigned R, int O, StringRef V) :
294       Operation(Op), Label(L), Register(R), Offset(O),
295       Values(V.begin(), V.end()) {
296       assert(Op != OpRegister);
297     }
298 
MCCFIInstruction(OpType Op,MCSymbol * L,unsigned R1,unsigned R2)299     MCCFIInstruction(OpType Op, MCSymbol *L, unsigned R1, unsigned R2) :
300       Operation(Op), Label(L), Register(R1), Register2(R2) {
301       assert(Op == OpRegister);
302     }
303 
304   public:
305     static MCCFIInstruction
createOffset(MCSymbol * L,unsigned Register,int Offset)306     createOffset(MCSymbol *L, unsigned Register, int Offset) {
307       return MCCFIInstruction(OpOffset, L, Register, Offset, "");
308     }
309 
310     static MCCFIInstruction
createDefCfaRegister(MCSymbol * L,unsigned Register)311     createDefCfaRegister(MCSymbol *L, unsigned Register) {
312       return MCCFIInstruction(OpDefCfaRegister, L, Register, 0, "");
313     }
314 
createDefCfaOffset(MCSymbol * L,int Offset)315     static MCCFIInstruction createDefCfaOffset(MCSymbol *L, int Offset) {
316       return MCCFIInstruction(OpDefCfaOffset, L, 0, -Offset, "");
317     }
318 
319     static MCCFIInstruction
createDefCfa(MCSymbol * L,unsigned Register,int Offset)320     createDefCfa(MCSymbol *L, unsigned Register, int Offset) {
321       return MCCFIInstruction(OpDefCfa, L, Register, -Offset, "");
322     }
323 
createUndefined(MCSymbol * L,unsigned Register)324     static MCCFIInstruction createUndefined(MCSymbol *L, unsigned Register) {
325       return MCCFIInstruction(OpUndefined, L, Register, 0, "");
326     }
327 
createRestore(MCSymbol * L,unsigned Register)328     static MCCFIInstruction createRestore(MCSymbol *L, unsigned Register) {
329       return MCCFIInstruction(OpRestore, L, Register, 0, "");
330     }
331 
createSameValue(MCSymbol * L,unsigned Register)332     static MCCFIInstruction createSameValue(MCSymbol *L, unsigned Register) {
333       return MCCFIInstruction(OpSameValue, L, Register, 0, "");
334     }
335 
createRestoreState(MCSymbol * L)336     static MCCFIInstruction createRestoreState(MCSymbol *L) {
337       return MCCFIInstruction(OpRestoreState, L, 0, 0, "");
338     }
339 
createRememberState(MCSymbol * L)340     static MCCFIInstruction createRememberState(MCSymbol *L) {
341       return MCCFIInstruction(OpRememberState, L, 0, 0, "");
342     }
343 
344     static MCCFIInstruction
createRelOffset(MCSymbol * L,unsigned Register,int Offset)345     createRelOffset(MCSymbol *L, unsigned Register, int Offset) {
346       return MCCFIInstruction(OpRelOffset, L, Register, Offset, "");
347     }
348 
349     static MCCFIInstruction
createAdjustCfaOffset(MCSymbol * L,int Adjustment)350     createAdjustCfaOffset(MCSymbol *L, int Adjustment) {
351       return MCCFIInstruction(OpAdjustCfaOffset, L, 0, Adjustment, "");
352     }
353 
createEscape(MCSymbol * L,StringRef Vals)354     static MCCFIInstruction createEscape(MCSymbol *L, StringRef Vals) {
355       return MCCFIInstruction(OpEscape, L, 0, 0, Vals);
356     }
357 
358    static MCCFIInstruction
createRegister(MCSymbol * L,unsigned Register1,unsigned Register2)359    createRegister(MCSymbol *L, unsigned Register1, unsigned Register2) {
360       return MCCFIInstruction(OpRegister, L, Register1, Register2);
361     }
362 
getOperation()363     OpType getOperation() const { return Operation; }
getLabel()364     MCSymbol *getLabel() const { return Label; }
365 
getRegister()366     unsigned getRegister() const {
367       assert(Operation == OpDefCfa || Operation == OpOffset ||
368              Operation == OpRestore || Operation == OpUndefined ||
369              Operation == OpSameValue || Operation == OpDefCfaRegister ||
370              Operation == OpRelOffset || Operation == OpRegister);
371       return Register;
372     }
373 
getRegister2()374     unsigned getRegister2() const {
375       assert(Operation == OpRegister);
376       return Register2;
377     }
378 
getOffset()379     int getOffset() const {
380       assert(Operation == OpDefCfa || Operation == OpOffset ||
381              Operation == OpRelOffset || Operation == OpDefCfaOffset ||
382              Operation == OpAdjustCfaOffset);
383       return Offset;
384     }
385 
getValues()386     const StringRef getValues() const {
387       assert(Operation == OpEscape);
388       return StringRef(&Values[0], Values.size());
389     }
390   };
391 
392   struct MCDwarfFrameInfo {
MCDwarfFrameInfoMCDwarfFrameInfo393     MCDwarfFrameInfo() : Begin(0), End(0), Personality(0), Lsda(0),
394                          Function(0), Instructions(), PersonalityEncoding(),
395                          LsdaEncoding(0), CompactUnwindEncoding(0),
396                          IsSignalFrame(false) {}
397     MCSymbol *Begin;
398     MCSymbol *End;
399     const MCSymbol *Personality;
400     const MCSymbol *Lsda;
401     const MCSymbol *Function;
402     std::vector<MCCFIInstruction> Instructions;
403     unsigned PersonalityEncoding;
404     unsigned LsdaEncoding;
405     uint32_t CompactUnwindEncoding;
406     bool IsSignalFrame;
407   };
408 
409   class MCDwarfFrameEmitter {
410   public:
411     //
412     // This emits the frame info section.
413     //
414     static void Emit(MCStreamer &streamer, bool usingCFI,
415                      bool isEH);
416     static void EmitAdvanceLoc(MCStreamer &Streamer, uint64_t AddrDelta);
417     static void EncodeAdvanceLoc(MCContext &Context, uint64_t AddrDelta,
418                                  raw_ostream &OS);
419   };
420 } // end namespace llvm
421 
422 #endif
423