src/llvm/include/llvm/MC/MCObjectStreamer.h

   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/ADT/SmallVector.h"
  14 #include "llvm/MC/MCAssembler.h"
  15 #include "llvm/MC/MCStreamer.h"
  16
  17 namespace llvm {
  18 class MCAssembler;
  19 class MCCodeEmitter;
  20 class MCSectionData;
  21 class MCSubtargetInfo;
  22 class MCExpr;
  23 class MCFragment;
  24 class MCDataFragment;
  25 class MCAsmBackend;
  26 class raw_ostream;
  27
  28 /// \brief Streaming object file generation interface.
  29 ///
  30 /// This class provides an implementation of the MCStreamer interface which is
  31 /// suitable for use with the assembler backend. Specific object file formats
  32 /// are expected to subclass this interface to implement directives specific
  33 /// to that file format or custom semantics expected by the object writer
  34 /// implementation.
  35 class MCObjectStreamer : public MCStreamer {
  36   MCAssembler *Assembler;
  37   MCSectionData *CurSectionData;
  38   MCSectionData::iterator CurInsertionPoint;
  39   bool EmitEHFrame;
  40   bool EmitDebugFrame;
  41   SmallVector<MCSymbolData *, 2> PendingLabels;
  42
  43   virtual void EmitInstToData(const MCInst &Inst, const MCSubtargetInfo&) = 0;
  44   void EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) override;
  45   void EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) override;
  46
  47   // If any labels have been emitted but not assigned fragments, ensure that
  48   // they get assigned, either to F if possible or to a new data fragment.
  49   void flushPendingLabels(MCFragment *F);
  50
  51 protected:
  52   MCObjectStreamer(MCContext &Context, MCAsmBackend &TAB, raw_ostream &_OS,
  53                    MCCodeEmitter *_Emitter);
  54   MCObjectStreamer(MCContext &Context, MCAsmBackend &TAB, raw_ostream &_OS,
  55                    MCCodeEmitter *_Emitter, MCAssembler *_Assembler);
  56   ~MCObjectStreamer();
  57
  58 public:
  59   /// state management
  60   void reset() override;
  61
  62   /// Object streamers require the integrated assembler.
  63   bool isIntegratedAssemblerRequired() const override { return true; }
  64
  65   MCSymbolData &getOrCreateSymbolData(const MCSymbol *Symbol) {
  66     return getAssembler().getOrCreateSymbolData(*Symbol);
  67   }
  68   void EmitFrames(MCAsmBackend *MAB);
  69   void EmitCFISections(bool EH, bool Debug) override;
  70
  71 protected:
  72   MCSectionData *getCurrentSectionData() const {
  73     return CurSectionData;
  74   }
  75
  76   MCFragment *getCurrentFragment() const;
  77
  78   void insert(MCFragment *F) {
  79     flushPendingLabels(F);
  80     CurSectionData->getFragmentList().insert(CurInsertionPoint, F);
  81     F->setParent(CurSectionData);
  82   }
  83
  84   /// Get a data fragment to write into, creating a new one if the current
  85   /// fragment is not a data fragment.
  86   MCDataFragment *getOrCreateDataFragment();
  87
  88 public:
  89   void visitUsedSymbol(const MCSymbol &Sym) override;
  90
  91   MCAssembler &getAssembler() { return *Assembler; }
  92
  93   /// @name MCStreamer Interface
  94   /// @{
  95
  96   void EmitLabel(MCSymbol *Symbol) override;
  97   void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) override;
  98   void EmitValueImpl(const MCExpr *Value, unsigned Size,
  99                      const SMLoc &Loc = SMLoc()) override;
 100   void EmitULEB128Value(const MCExpr *Value) override;
 101   void EmitSLEB128Value(const MCExpr *Value) override;
 102   void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) override;
 103   void ChangeSection(const MCSection *Section,
 104                      const MCExpr *Subsection) override;
 105   void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo& STI) override;
 106
 107   /// \brief Emit an instruction to a special fragment, because this instruction
 108   /// can change its size during relaxation.
 109   virtual void EmitInstToFragment(const MCInst &Inst, const MCSubtargetInfo &);
 110
 111   void EmitBundleAlignMode(unsigned AlignPow2) override;
 112   void EmitBundleLock(bool AlignToEnd) override;
 113   void EmitBundleUnlock() override;
 114   void EmitBytes(StringRef Data) override;
 115   void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
 116                             unsigned ValueSize = 1,
 117                             unsigned MaxBytesToEmit = 0) override;
 118   void EmitCodeAlignment(unsigned ByteAlignment,
 119                          unsigned MaxBytesToEmit = 0) override;
 120   bool EmitValueToOffset(const MCExpr *Offset, unsigned char Value) override;
 121   void EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
 122                              unsigned Column, unsigned Flags,
 123                              unsigned Isa, unsigned Discriminator,
 124                              StringRef FileName) override;
 125   void EmitDwarfAdvanceLineAddr(int64_t LineDelta, const MCSymbol *LastLabel,
 126                                 const MCSymbol *Label,
 127                                 unsigned PointerSize);
 128   void EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
 129                                  const MCSymbol *Label);
 130   void EmitGPRel32Value(const MCExpr *Value) override;
 131   void EmitGPRel64Value(const MCExpr *Value) override;
 132   void EmitFill(uint64_t NumBytes, uint8_t FillValue) override;
 133   void EmitZeros(uint64_t NumBytes) override;
 134   void FinishImpl() override;
 135
 136   bool mayHaveInstructions() const override {
 137     return getCurrentSectionData()->hasInstructions();
 138   }
 139 };
 140
 141 } // end namespace llvm
 142
 143 #endif