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 #include "llvm/MC/MCContext.h"
12 #include "llvm/MC/MCInst.h"
13 #include "llvm/MC/MCSectionMachO.h"
14 #include "llvm/MC/MCSymbol.h"
15 
16 using namespace llvm;
17 
18 namespace {
19 
20   class MCNullStreamer : public MCStreamer {
21   public:
22     MCNullStreamer(MCContext &Context) : MCStreamer(Context) {}
23 
24     /// @name MCStreamer Interface
25     /// @{
26 
27     virtual void ChangeSection(const MCSection *Section,
28                                const MCExpr *Subsection) {
29     }
30 
31     virtual void EmitLabel(MCSymbol *Symbol) {
32       assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
33       assert(getCurrentSection().first &&"Cannot emit before setting section!");
34       AssignSection(Symbol, getCurrentSection().first);
35     }
36     virtual void EmitDebugLabel(MCSymbol *Symbol) {
37       EmitLabel(Symbol);
38     }
39     virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) {}
40     virtual void EmitThumbFunc(MCSymbol *Func) {}
41 
42     virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {}
43     virtual void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol){}
44     virtual void EmitDwarfAdvanceLineAddr(int64_t LineDelta,
45                                           const MCSymbol *LastLabel,
46                                           const MCSymbol *Label,
47                                           unsigned PointerSize) {}
48 
49     virtual bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute){
50       return true;
51     }
52 
53     virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {}
54 
55     virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) {}
56     virtual void EmitCOFFSymbolStorageClass(int StorageClass) {}
57     virtual void EmitCOFFSymbolType(int Type) {}
58     virtual void EndCOFFSymbolDef() {}
59     virtual void EmitCOFFSecRel32(MCSymbol const *Symbol) {}
60 
61     virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {}
62     virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
63                                   unsigned ByteAlignment) {}
64     virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
65                                        unsigned ByteAlignment) {}
66     virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
67                               uint64_t Size = 0, unsigned ByteAlignment = 0) {}
68     virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
69                                 uint64_t Size, unsigned ByteAlignment) {}
70     virtual void EmitBytes(StringRef Data) {}
71 
72     virtual void EmitValueImpl(const MCExpr *Value, unsigned Size) {}
73     virtual void EmitULEB128Value(const MCExpr *Value) {}
74     virtual void EmitSLEB128Value(const MCExpr *Value) {}
75     virtual void EmitGPRel32Value(const MCExpr *Value) {}
76     virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
77                                       unsigned ValueSize = 1,
78                                       unsigned MaxBytesToEmit = 0) {}
79 
80     virtual void EmitCodeAlignment(unsigned ByteAlignment,
81                                    unsigned MaxBytesToEmit = 0) {}
82 
83     virtual bool EmitValueToOffset(const MCExpr *Offset,
84                                    unsigned char Value = 0) { return false; }
85 
86     virtual void EmitFileDirective(StringRef Filename) {}
87     virtual bool EmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
88                                         StringRef Filename, unsigned CUID = 0) {
89       return false;
90     }
91     virtual void EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
92                                        unsigned Column, unsigned Flags,
93                                        unsigned Isa, unsigned Discriminator,
94                                        StringRef FileName) {}
95     virtual void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo&) {}
96 
97     virtual void EmitBundleAlignMode(unsigned AlignPow2) {}
98     virtual void EmitBundleLock(bool AlignToEnd) {}
99     virtual void EmitBundleUnlock() {}
100 
101     virtual void FinishImpl() {}
102 
103     virtual void EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
104       RecordProcEnd(Frame);
105     }
106   };
107 
108 }
109 
110 MCStreamer *llvm::createNullStreamer(MCContext &Context) {
111   return new MCNullStreamer(Context);
112 }
113