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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 MCObjectWriter;
     28   class MCSection;
     29   class MCStreamer;
     30   class MCSymbol;
     31   class SourceMgr;
     32   class SMLoc;
     33 
     34   /// MCDwarfFile - Instances of this class represent the name of the dwarf
     35   /// .file directive and its associated dwarf file number in the MC file,
     36   /// and MCDwarfFile's are created and unique'd by the MCContext class where
     37   /// the file number for each is its index into the vector of DwarfFiles (note
     38   /// index 0 is not used and not a valid dwarf file number).
     39   class MCDwarfFile {
     40     // Name - the base name of the file without its directory path.
     41     // The StringRef references memory allocated in the MCContext.
     42     StringRef Name;
     43 
     44     // DirIndex - the index into the list of directory names for this file name.
     45     unsigned DirIndex;
     46 
     47   private:  // MCContext creates and uniques these.
     48     friend class MCContext;
     49     MCDwarfFile(StringRef name, unsigned dirIndex)
     50       : Name(name), DirIndex(dirIndex) {}
     51 
     52     MCDwarfFile(const MCDwarfFile&) LLVM_DELETED_FUNCTION;
     53     void operator=(const MCDwarfFile&) LLVM_DELETED_FUNCTION;
     54   public:
     55     /// getName - Get the base name of this MCDwarfFile.
     56     StringRef getName() const { return Name; }
     57 
     58     /// getDirIndex - Get the dirIndex of this MCDwarfFile.
     59     unsigned getDirIndex() const { return DirIndex; }
     60 
     61 
     62     /// print - Print the value to the stream \p OS.
     63     void print(raw_ostream &OS) const;
     64 
     65     /// dump - Print the value to stderr.
     66     void dump() const;
     67   };
     68 
     69   inline raw_ostream &operator<<(raw_ostream &OS, const MCDwarfFile &DwarfFile){
     70     DwarfFile.print(OS);
     71     return OS;
     72   }
     73 
     74   /// MCDwarfLoc - Instances of this class represent the information from a
     75   /// dwarf .loc directive.
     76   class MCDwarfLoc {
     77     // FileNum - the file number.
     78     unsigned FileNum;
     79     // Line - the line number.
     80     unsigned Line;
     81     // Column - the column position.
     82     unsigned Column;
     83     // Flags (see #define's below)
     84     unsigned Flags;
     85     // Isa
     86     unsigned Isa;
     87     // Discriminator
     88     unsigned Discriminator;
     89 
     90 // Flag that indicates the initial value of the is_stmt_start flag.
     91 #define DWARF2_LINE_DEFAULT_IS_STMT     1
     92 
     93 #define DWARF2_FLAG_IS_STMT        (1 << 0)
     94 #define DWARF2_FLAG_BASIC_BLOCK    (1 << 1)
     95 #define DWARF2_FLAG_PROLOGUE_END   (1 << 2)
     96 #define DWARF2_FLAG_EPILOGUE_BEGIN (1 << 3)
     97 
     98   private:  // MCContext manages these
     99     friend class MCContext;
    100     friend class MCLineEntry;
    101     MCDwarfLoc(unsigned fileNum, unsigned line, unsigned column, unsigned flags,
    102                unsigned isa, unsigned discriminator)
    103       : FileNum(fileNum), Line(line), Column(column), Flags(flags), Isa(isa),
    104         Discriminator(discriminator) {}
    105 
    106     // Allow the default copy constructor and assignment operator to be used
    107     // for an MCDwarfLoc object.
    108 
    109   public:
    110     /// getFileNum - Get the FileNum of this MCDwarfLoc.
    111     unsigned getFileNum() const { return FileNum; }
    112 
    113     /// getLine - Get the Line of this MCDwarfLoc.
    114     unsigned getLine() const { return Line; }
    115 
    116     /// getColumn - Get the Column of this MCDwarfLoc.
    117     unsigned getColumn() const { return Column; }
    118 
    119     /// getFlags - Get the Flags of this MCDwarfLoc.
    120     unsigned getFlags() const { return Flags; }
    121 
    122     /// getIsa - Get the Isa of this MCDwarfLoc.
    123     unsigned getIsa() const { return Isa; }
    124 
    125     /// getDiscriminator - Get the Discriminator of this MCDwarfLoc.
    126     unsigned getDiscriminator() const { return Discriminator; }
    127 
    128     /// setFileNum - Set the FileNum of this MCDwarfLoc.
    129     void setFileNum(unsigned fileNum) { FileNum = fileNum; }
    130 
    131     /// setLine - Set the Line of this MCDwarfLoc.
    132     void setLine(unsigned line) { Line = line; }
    133 
    134     /// setColumn - Set the Column of this MCDwarfLoc.
    135     void setColumn(unsigned column) { Column = column; }
    136 
    137     /// setFlags - Set the Flags of this MCDwarfLoc.
    138     void setFlags(unsigned flags) { Flags = flags; }
    139 
    140     /// setIsa - Set the Isa of this MCDwarfLoc.
    141     void setIsa(unsigned isa) { Isa = isa; }
    142 
    143     /// setDiscriminator - Set the Discriminator of this MCDwarfLoc.
    144     void setDiscriminator(unsigned discriminator) {
    145       Discriminator = discriminator;
    146     }
    147   };
    148 
    149   /// MCLineEntry - Instances of this class represent the line information for
    150   /// the dwarf line table entries.  Which is created after a machine
    151   /// instruction is assembled and uses an address from a temporary label
    152   /// created at the current address in the current section and the info from
    153   /// the last .loc directive seen as stored in the context.
    154   class MCLineEntry : public MCDwarfLoc {
    155     MCSymbol *Label;
    156 
    157   private:
    158     // Allow the default copy constructor and assignment operator to be used
    159     // for an MCLineEntry object.
    160 
    161   public:
    162     // Constructor to create an MCLineEntry given a symbol and the dwarf loc.
    163     MCLineEntry(MCSymbol *label, const MCDwarfLoc loc) : MCDwarfLoc(loc),
    164                 Label(label) {}
    165 
    166     MCSymbol *getLabel() const { return Label; }
    167 
    168     // This is called when an instruction is assembled into the specified
    169     // section and if there is information from the last .loc directive that
    170     // has yet to have a line entry made for it is made.
    171     static void Make(MCStreamer *MCOS, const MCSection *Section);
    172   };
    173 
    174   /// MCLineSection - Instances of this class represent the line information
    175   /// for a section where machine instructions have been assembled after seeing
    176   /// .loc directives.  This is the information used to build the dwarf line
    177   /// table for a section.
    178   class MCLineSection {
    179 
    180   private:
    181     MCLineSection(const MCLineSection&) LLVM_DELETED_FUNCTION;
    182     void operator=(const MCLineSection&) LLVM_DELETED_FUNCTION;
    183 
    184   public:
    185     // Constructor to create an MCLineSection with an empty MCLineEntries
    186     // vector.
    187     MCLineSection() {}
    188 
    189     // addLineEntry - adds an entry to this MCLineSection's line entries
    190     void addLineEntry(const MCLineEntry &LineEntry, unsigned CUID) {
    191       MCLineDivisions[CUID].push_back(LineEntry);
    192     }
    193 
    194     typedef std::vector<MCLineEntry> MCLineEntryCollection;
    195     typedef MCLineEntryCollection::iterator iterator;
    196     typedef MCLineEntryCollection::const_iterator const_iterator;
    197     typedef std::map<unsigned, MCLineEntryCollection> MCLineDivisionMap;
    198 
    199   private:
    200     // A collection of MCLineEntry for each Compile Unit ID.
    201     MCLineDivisionMap MCLineDivisions;
    202 
    203   public:
    204     // Returns whether MCLineSection contains entries for a given Compile
    205     // Unit ID.
    206     bool containEntriesForID(unsigned CUID) const {
    207       return MCLineDivisions.count(CUID);
    208     }
    209     // Returns the collection of MCLineEntry for a given Compile Unit ID.
    210     const MCLineEntryCollection &getMCLineEntries(unsigned CUID) const {
    211       MCLineDivisionMap::const_iterator CIter = MCLineDivisions.find(CUID);
    212       assert(CIter != MCLineDivisions.end());
    213       return CIter->second;
    214     }
    215   };
    216 
    217   class MCDwarfFileTable {
    218   public:
    219     //
    220     // This emits the Dwarf file and the line tables for all Compile Units.
    221     //
    222     static const MCSymbol *Emit(MCStreamer *MCOS);
    223     //
    224     // This emits the Dwarf file and the line tables for a given Compile Unit.
    225     //
    226     static const MCSymbol *EmitCU(MCStreamer *MCOS, unsigned ID);
    227   };
    228 
    229   class MCDwarfLineAddr {
    230   public:
    231     /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
    232     static void Encode(int64_t LineDelta, 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     /// Utility function to write the encoding to an object writer.
    239     static void Write(MCObjectWriter *OW,
    240                       int64_t LineDelta, uint64_t AddrDelta);
    241   };
    242 
    243   class MCGenDwarfInfo {
    244   public:
    245     //
    246     // When generating dwarf for assembly source files this emits the Dwarf
    247     // sections.
    248     //
    249     static void Emit(MCStreamer *MCOS, const MCSymbol *LineSectionSymbol);
    250   };
    251 
    252   // When generating dwarf for assembly source files this is the info that is
    253   // needed to be gathered for each symbol that will have a dwarf label.
    254   class MCGenDwarfLabelEntry {
    255   private:
    256     // Name of the symbol without a leading underbar, if any.
    257     StringRef Name;
    258     // The dwarf file number this symbol is in.
    259     unsigned FileNumber;
    260     // The line number this symbol is at.
    261     unsigned LineNumber;
    262     // The low_pc for the dwarf label is taken from this symbol.
    263     MCSymbol *Label;
    264 
    265   public:
    266     MCGenDwarfLabelEntry(StringRef name, unsigned fileNumber,
    267                          unsigned lineNumber, MCSymbol *label) :
    268       Name(name), FileNumber(fileNumber), LineNumber(lineNumber), Label(label){}
    269 
    270     StringRef getName() const { return Name; }
    271     unsigned getFileNumber() const { return FileNumber; }
    272     unsigned getLineNumber() const { return LineNumber; }
    273     MCSymbol *getLabel() const { return Label; }
    274 
    275     // This is called when label is created when we are generating dwarf for
    276     // assembly source files.
    277     static void Make(MCSymbol *Symbol, MCStreamer *MCOS, SourceMgr &SrcMgr,
    278                      SMLoc &Loc);
    279   };
    280 
    281   class MCCFIInstruction {
    282   public:
    283     enum OpType { OpSameValue, OpRememberState, OpRestoreState, OpOffset,
    284                   OpDefCfaRegister, OpDefCfaOffset, OpDefCfa, OpRelOffset,
    285                   OpAdjustCfaOffset, OpEscape, OpRestore, OpUndefined,
    286                   OpRegister };
    287   private:
    288     OpType Operation;
    289     MCSymbol *Label;
    290     unsigned Register;
    291     union {
    292       int Offset;
    293       unsigned Register2;
    294     };
    295     std::vector<char> Values;
    296 
    297     MCCFIInstruction(OpType Op, MCSymbol *L, unsigned R, int O, StringRef V) :
    298       Operation(Op), Label(L), Register(R), Offset(O),
    299       Values(V.begin(), V.end()) {
    300       assert(Op != OpRegister);
    301     }
    302 
    303     MCCFIInstruction(OpType Op, MCSymbol *L, unsigned R1, unsigned R2) :
    304       Operation(Op), Label(L), Register(R1), Register2(R2) {
    305       assert(Op == OpRegister);
    306     }
    307 
    308   public:
    309     static MCCFIInstruction
    310     createOffset(MCSymbol *L, unsigned Register, int Offset) {
    311       return MCCFIInstruction(OpOffset, L, Register, Offset, "");
    312     }
    313 
    314     static MCCFIInstruction
    315     createDefCfaRegister(MCSymbol *L, unsigned Register) {
    316       return MCCFIInstruction(OpDefCfaRegister, L, Register, 0, "");
    317     }
    318 
    319     static MCCFIInstruction createDefCfaOffset(MCSymbol *L, int Offset) {
    320       return MCCFIInstruction(OpDefCfaOffset, L, 0, -Offset, "");
    321     }
    322 
    323     static MCCFIInstruction
    324     createDefCfa(MCSymbol *L, unsigned Register, int Offset) {
    325       return MCCFIInstruction(OpDefCfa, L, Register, -Offset, "");
    326     }
    327 
    328     static MCCFIInstruction createUndefined(MCSymbol *L, unsigned Register) {
    329       return MCCFIInstruction(OpUndefined, L, Register, 0, "");
    330     }
    331 
    332     static MCCFIInstruction createRestore(MCSymbol *L, unsigned Register) {
    333       return MCCFIInstruction(OpRestore, L, Register, 0, "");
    334     }
    335 
    336     static MCCFIInstruction createSameValue(MCSymbol *L, unsigned Register) {
    337       return MCCFIInstruction(OpSameValue, L, Register, 0, "");
    338     }
    339 
    340     static MCCFIInstruction createRestoreState(MCSymbol *L) {
    341       return MCCFIInstruction(OpRestoreState, L, 0, 0, "");
    342     }
    343 
    344     static MCCFIInstruction createRememberState(MCSymbol *L) {
    345       return MCCFIInstruction(OpRememberState, L, 0, 0, "");
    346     }
    347 
    348     static MCCFIInstruction
    349     createRelOffset(MCSymbol *L, unsigned Register, int Offset) {
    350       return MCCFIInstruction(OpRelOffset, L, Register, Offset, "");
    351     }
    352 
    353     static MCCFIInstruction
    354     createAdjustCfaOffset(MCSymbol *L, int Adjustment) {
    355       return MCCFIInstruction(OpAdjustCfaOffset, L, 0, Adjustment, "");
    356     }
    357 
    358     static MCCFIInstruction createEscape(MCSymbol *L, StringRef Vals) {
    359       return MCCFIInstruction(OpEscape, L, 0, 0, Vals);
    360     }
    361 
    362    static MCCFIInstruction
    363    createRegister(MCSymbol *L, unsigned Register1, unsigned Register2) {
    364       return MCCFIInstruction(OpRegister, L, Register1, Register2);
    365     }
    366 
    367     OpType getOperation() const { return Operation; }
    368     MCSymbol *getLabel() const { return Label; }
    369 
    370     unsigned getRegister() const {
    371       assert(Operation == OpDefCfa || Operation == OpOffset ||
    372              Operation == OpRestore || Operation == OpUndefined ||
    373              Operation == OpSameValue || Operation == OpDefCfaRegister ||
    374              Operation == OpRelOffset || Operation == OpRegister);
    375       return Register;
    376     }
    377 
    378     unsigned getRegister2() const {
    379       assert(Operation == OpRegister);
    380       return Register2;
    381     }
    382 
    383     int getOffset() const {
    384       assert(Operation == OpDefCfa || Operation == OpOffset ||
    385              Operation == OpRelOffset || Operation == OpDefCfaOffset ||
    386              Operation == OpAdjustCfaOffset);
    387       return Offset;
    388     }
    389 
    390     const StringRef getValues() const {
    391       assert(Operation == OpEscape);
    392       return StringRef(&Values[0], Values.size());
    393     }
    394   };
    395 
    396   struct MCDwarfFrameInfo {
    397     MCDwarfFrameInfo() : Begin(0), End(0), Personality(0), Lsda(0),
    398                          Function(0), Instructions(), PersonalityEncoding(),
    399                          LsdaEncoding(0), CompactUnwindEncoding(0),
    400                          IsSignalFrame(false) {}
    401     MCSymbol *Begin;
    402     MCSymbol *End;
    403     const MCSymbol *Personality;
    404     const MCSymbol *Lsda;
    405     const MCSymbol *Function;
    406     std::vector<MCCFIInstruction> Instructions;
    407     unsigned PersonalityEncoding;
    408     unsigned LsdaEncoding;
    409     uint32_t CompactUnwindEncoding;
    410     bool IsSignalFrame;
    411   };
    412 
    413   class MCDwarfFrameEmitter {
    414   public:
    415     //
    416     // This emits the frame info section.
    417     //
    418     static void Emit(MCStreamer &streamer, bool usingCFI,
    419                      bool isEH);
    420     static void EmitAdvanceLoc(MCStreamer &Streamer, uint64_t AddrDelta);
    421     static void EncodeAdvanceLoc(uint64_t AddrDelta, raw_ostream &OS);
    422   };
    423 } // end namespace llvm
    424 
    425 #endif
    426