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      1 //===- lib/MC/MCNullStreamer.cpp - Dummy Streamer Implementation ----------===//
      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 #include "llvm/MC/MCStreamer.h"
     11 
     12 #include "llvm/MC/MCContext.h"
     13 #include "llvm/MC/MCInst.h"
     14 #include "llvm/MC/MCSectionMachO.h"
     15 #include "llvm/MC/MCSymbol.h"
     16 
     17 using namespace llvm;
     18 
     19 namespace {
     20 
     21   class MCNullStreamer : public MCStreamer {
     22   public:
     23     MCNullStreamer(MCContext &Context) : MCStreamer(Context) {}
     24 
     25     /// @name MCStreamer Interface
     26     /// @{
     27 
     28     virtual void InitSections() {
     29     }
     30 
     31     virtual void ChangeSection(const MCSection *Section) {
     32     }
     33 
     34     virtual void EmitLabel(MCSymbol *Symbol) {
     35       assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
     36       assert(getCurrentSection() && "Cannot emit before setting section!");
     37       Symbol->setSection(*getCurrentSection());
     38     }
     39 
     40     virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) {}
     41     virtual void EmitThumbFunc(MCSymbol *Func) {}
     42 
     43     virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {}
     44     virtual void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol){}
     45     virtual void EmitDwarfAdvanceLineAddr(int64_t LineDelta,
     46                                           const MCSymbol *LastLabel,
     47                                           const MCSymbol *Label,
     48                                           unsigned PointerSize) {}
     49 
     50     virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute){}
     51 
     52     virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {}
     53 
     54     virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) {}
     55     virtual void EmitCOFFSymbolStorageClass(int StorageClass) {}
     56     virtual void EmitCOFFSymbolType(int Type) {}
     57     virtual void EndCOFFSymbolDef() {}
     58 
     59     virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {}
     60     virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
     61                                   unsigned ByteAlignment) {}
     62     virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
     63                                        unsigned ByteAlignment) {}
     64     virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
     65                               unsigned Size = 0, unsigned ByteAlignment = 0) {}
     66     virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
     67                                 uint64_t Size, unsigned ByteAlignment) {}
     68     virtual void EmitBytes(StringRef Data, unsigned AddrSpace) {}
     69 
     70     virtual void EmitValueImpl(const MCExpr *Value, unsigned Size,
     71                                unsigned AddrSpace) {}
     72     virtual void EmitULEB128Value(const MCExpr *Value) {}
     73     virtual void EmitSLEB128Value(const MCExpr *Value) {}
     74     virtual void EmitGPRel32Value(const MCExpr *Value) {}
     75     virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
     76                                       unsigned ValueSize = 1,
     77                                       unsigned MaxBytesToEmit = 0) {}
     78 
     79     virtual void EmitCodeAlignment(unsigned ByteAlignment,
     80                                    unsigned MaxBytesToEmit = 0) {}
     81 
     82     virtual void EmitValueToOffset(const MCExpr *Offset,
     83                                    unsigned char Value = 0) {}
     84 
     85     virtual void EmitFileDirective(StringRef Filename) {}
     86     virtual bool EmitDwarfFileDirective(unsigned FileNo,StringRef Filename) {
     87       return false;
     88     }
     89     virtual void EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
     90                                        unsigned Column, unsigned Flags,
     91                                        unsigned Isa, unsigned Discriminator,
     92                                        StringRef FileName) {}
     93     virtual void EmitInstruction(const MCInst &Inst) {}
     94 
     95     virtual void Finish() {}
     96 
     97     /// @}
     98   };
     99 
    100 }
    101 
    102 MCStreamer *llvm::createNullStreamer(MCContext &Context) {
    103   return new MCNullStreamer(Context);
    104 }
    105