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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;
     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, 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.
    205     bool containEntriesForID(unsigned CUID) const {
    206       return MCLineDivisions.count(CUID);
    207     }
    208     // Returns the collection of MCLineEntry for a given Compile Unit ID.
    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:
    262     MCGenDwarfLabelEntry(StringRef name, unsigned fileNumber,
    263                          unsigned lineNumber, MCSymbol *label) :
    264       Name(name), FileNumber(fileNumber), LineNumber(lineNumber), Label(label){}
    265 
    266     StringRef getName() const { return Name; }
    267     unsigned getFileNumber() const { return FileNumber; }
    268     unsigned getLineNumber() const { return LineNumber; }
    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 
    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 
    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
    306     createOffset(MCSymbol *L, unsigned Register, int Offset) {
    307       return MCCFIInstruction(OpOffset, L, Register, Offset, "");
    308     }
    309 
    310     static MCCFIInstruction
    311     createDefCfaRegister(MCSymbol *L, unsigned Register) {
    312       return MCCFIInstruction(OpDefCfaRegister, L, Register, 0, "");
    313     }
    314 
    315     static MCCFIInstruction createDefCfaOffset(MCSymbol *L, int Offset) {
    316       return MCCFIInstruction(OpDefCfaOffset, L, 0, -Offset, "");
    317     }
    318 
    319     static MCCFIInstruction
    320     createDefCfa(MCSymbol *L, unsigned Register, int Offset) {
    321       return MCCFIInstruction(OpDefCfa, L, Register, -Offset, "");
    322     }
    323 
    324     static MCCFIInstruction createUndefined(MCSymbol *L, unsigned Register) {
    325       return MCCFIInstruction(OpUndefined, L, Register, 0, "");
    326     }
    327 
    328     static MCCFIInstruction createRestore(MCSymbol *L, unsigned Register) {
    329       return MCCFIInstruction(OpRestore, L, Register, 0, "");
    330     }
    331 
    332     static MCCFIInstruction createSameValue(MCSymbol *L, unsigned Register) {
    333       return MCCFIInstruction(OpSameValue, L, Register, 0, "");
    334     }
    335 
    336     static MCCFIInstruction createRestoreState(MCSymbol *L) {
    337       return MCCFIInstruction(OpRestoreState, L, 0, 0, "");
    338     }
    339 
    340     static MCCFIInstruction createRememberState(MCSymbol *L) {
    341       return MCCFIInstruction(OpRememberState, L, 0, 0, "");
    342     }
    343 
    344     static MCCFIInstruction
    345     createRelOffset(MCSymbol *L, unsigned Register, int Offset) {
    346       return MCCFIInstruction(OpRelOffset, L, Register, Offset, "");
    347     }
    348 
    349     static MCCFIInstruction
    350     createAdjustCfaOffset(MCSymbol *L, int Adjustment) {
    351       return MCCFIInstruction(OpAdjustCfaOffset, L, 0, Adjustment, "");
    352     }
    353 
    354     static MCCFIInstruction createEscape(MCSymbol *L, StringRef Vals) {
    355       return MCCFIInstruction(OpEscape, L, 0, 0, Vals);
    356     }
    357 
    358    static MCCFIInstruction
    359    createRegister(MCSymbol *L, unsigned Register1, unsigned Register2) {
    360       return MCCFIInstruction(OpRegister, L, Register1, Register2);
    361     }
    362 
    363     OpType getOperation() const { return Operation; }
    364     MCSymbol *getLabel() const { return Label; }
    365 
    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 
    374     unsigned getRegister2() const {
    375       assert(Operation == OpRegister);
    376       return Register2;
    377     }
    378 
    379     int getOffset() const {
    380       assert(Operation == OpDefCfa || Operation == OpOffset ||
    381              Operation == OpRelOffset || Operation == OpDefCfaOffset ||
    382              Operation == OpAdjustCfaOffset);
    383       return Offset;
    384     }
    385 
    386     const StringRef getValues() const {
    387       assert(Operation == OpEscape);
    388       return StringRef(&Values[0], Values.size());
    389     }
    390   };
    391 
    392   struct MCDwarfFrameInfo {
    393     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