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      1 //===- MCObjectStreamer.h - MCStreamer Object File Interface ----*- 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_MC_MCOBJECTSTREAMER_H
     11 #define LLVM_MC_MCOBJECTSTREAMER_H
     12 
     13 #include "llvm/MC/MCStreamer.h"
     14 
     15 namespace llvm {
     16 class MCAssembler;
     17 class MCCodeEmitter;
     18 class MCSectionData;
     19 class MCExpr;
     20 class MCFragment;
     21 class MCDataFragment;
     22 class MCAsmBackend;
     23 class raw_ostream;
     24 
     25 /// \brief Streaming object file generation interface.
     26 ///
     27 /// This class provides an implementation of the MCStreamer interface which is
     28 /// suitable for use with the assembler backend. Specific object file formats
     29 /// are expected to subclass this interface to implement directives specific
     30 /// to that file format or custom semantics expected by the object writer
     31 /// implementation.
     32 class MCObjectStreamer : public MCStreamer {
     33   MCAssembler *Assembler;
     34   MCSectionData *CurSectionData;
     35 
     36   virtual void EmitInstToData(const MCInst &Inst) = 0;
     37   virtual void EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame);
     38   virtual void EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame);
     39 
     40 protected:
     41   MCObjectStreamer(StreamerKind Kind, MCContext &Context, MCAsmBackend &TAB,
     42                    raw_ostream &_OS, MCCodeEmitter *_Emitter);
     43   MCObjectStreamer(StreamerKind Kind, MCContext &Context, MCAsmBackend &TAB,
     44                    raw_ostream &_OS, MCCodeEmitter *_Emitter,
     45                    MCAssembler *_Assembler);
     46   ~MCObjectStreamer();
     47 
     48 public:
     49   /// state management
     50   virtual void reset();
     51 
     52 protected:
     53   MCSectionData *getCurrentSectionData() const {
     54     return CurSectionData;
     55   }
     56 
     57   MCFragment *getCurrentFragment() const;
     58 
     59   /// Get a data fragment to write into, creating a new one if the current
     60   /// fragment is not a data fragment.
     61   MCDataFragment *getOrCreateDataFragment() const;
     62 
     63   const MCExpr *AddValueSymbols(const MCExpr *Value);
     64 
     65 public:
     66   MCAssembler &getAssembler() { return *Assembler; }
     67 
     68   /// @name MCStreamer Interface
     69   /// @{
     70 
     71   virtual void EmitLabel(MCSymbol *Symbol);
     72   virtual void EmitDebugLabel(MCSymbol *Symbol);
     73   virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
     74   virtual void EmitValueImpl(const MCExpr *Value, unsigned Size,
     75                              unsigned AddrSpace);
     76   virtual void EmitULEB128Value(const MCExpr *Value);
     77   virtual void EmitSLEB128Value(const MCExpr *Value);
     78   virtual void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol);
     79   virtual void ChangeSection(const MCSection *Section);
     80   virtual void EmitInstruction(const MCInst &Inst);
     81 
     82   /// \brief Emit an instruction to a special fragment, because this instruction
     83   /// can change its size during relaxation.
     84   virtual void EmitInstToFragment(const MCInst &Inst);
     85 
     86   virtual void EmitBundleAlignMode(unsigned AlignPow2);
     87   virtual void EmitBundleLock(bool AlignToEnd);
     88   virtual void EmitBundleUnlock();
     89   virtual void EmitBytes(StringRef Data, unsigned AddrSpace = 0);
     90   virtual void EmitValueToAlignment(unsigned ByteAlignment,
     91                                     int64_t Value = 0,
     92                                     unsigned ValueSize = 1,
     93                                     unsigned MaxBytesToEmit = 0);
     94   virtual void EmitCodeAlignment(unsigned ByteAlignment,
     95                                  unsigned MaxBytesToEmit = 0);
     96   virtual bool EmitValueToOffset(const MCExpr *Offset, unsigned char Value);
     97   virtual void EmitDwarfAdvanceLineAddr(int64_t LineDelta,
     98                                         const MCSymbol *LastLabel,
     99                                         const MCSymbol *Label,
    100                                         unsigned PointerSize);
    101   virtual void EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
    102                                          const MCSymbol *Label);
    103   virtual void EmitGPRel32Value(const MCExpr *Value);
    104   virtual void EmitGPRel64Value(const MCExpr *Value);
    105   virtual void EmitFill(uint64_t NumBytes, uint8_t FillValue,
    106                         unsigned AddrSpace = 0);
    107   virtual void FinishImpl();
    108 
    109   /// @}
    110 
    111   static bool classof(const MCStreamer *S) {
    112     return S->getKind() >= SK_ELFStreamer && S->getKind() <= SK_WinCOFFStreamer;
    113   }
    114 };
    115 
    116 } // end namespace llvm
    117 
    118 #endif
    119