1 //===- lib/MC/MCPureStreamer.cpp - MC "Pure" Object Output ----------------===// 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/MCAssembler.h" 12 #include "llvm/MC/MCCodeEmitter.h" 13 #include "llvm/MC/MCContext.h" 14 #include "llvm/MC/MCExpr.h" 15 #include "llvm/MC/MCObjectFileInfo.h" 16 #include "llvm/MC/MCObjectStreamer.h" 17 #include "llvm/MC/MCSymbol.h" 18 #include "llvm/Support/ErrorHandling.h" 19 20 using namespace llvm; 21 22 namespace { 23 24 class MCPureStreamer : public MCObjectStreamer { 25 private: 26 virtual void EmitInstToFragment(const MCInst &Inst); 27 virtual void EmitInstToData(const MCInst &Inst); 28 29 public: 30 MCPureStreamer(MCContext &Context, MCAsmBackend &TAB, raw_ostream &OS, 31 MCCodeEmitter *Emitter) 32 : MCObjectStreamer(SK_PureStreamer, Context, TAB, OS, Emitter) {} 33 34 /// @name MCStreamer Interface 35 /// @{ 36 37 virtual void InitSections(); 38 virtual void InitToTextSection(); 39 virtual void EmitLabel(MCSymbol *Symbol); 40 virtual void EmitDebugLabel(MCSymbol *Symbol); 41 virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0, 42 uint64_t Size = 0, unsigned ByteAlignment = 0); 43 virtual void EmitBytes(StringRef Data); 44 virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0, 45 unsigned ValueSize = 1, 46 unsigned MaxBytesToEmit = 0); 47 virtual void EmitCodeAlignment(unsigned ByteAlignment, 48 unsigned MaxBytesToEmit = 0); 49 virtual bool EmitValueToOffset(const MCExpr *Offset, 50 unsigned char Value = 0); 51 virtual void FinishImpl(); 52 53 54 virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) { 55 report_fatal_error("unsupported directive in pure streamer"); 56 } 57 virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) { 58 report_fatal_error("unsupported directive in pure streamer"); 59 } 60 virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol, 61 uint64_t Size, unsigned ByteAlignment = 0) { 62 report_fatal_error("unsupported directive in pure streamer"); 63 } 64 virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) { 65 report_fatal_error("unsupported directive in pure streamer"); 66 } 67 virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size, 68 unsigned ByteAlignment) { 69 report_fatal_error("unsupported directive in pure streamer"); 70 } 71 virtual void EmitThumbFunc(MCSymbol *Func) { 72 report_fatal_error("unsupported directive in pure streamer"); 73 } 74 virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) { 75 report_fatal_error("unsupported directive in pure streamer"); 76 } 77 virtual void EmitCOFFSymbolStorageClass(int StorageClass) { 78 report_fatal_error("unsupported directive in pure streamer"); 79 } 80 virtual void EmitCOFFSymbolType(int Type) { 81 report_fatal_error("unsupported directive in pure streamer"); 82 } 83 virtual void EndCOFFSymbolDef() { 84 report_fatal_error("unsupported directive in pure streamer"); 85 } 86 virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) { 87 report_fatal_error("unsupported directive in pure streamer"); 88 } 89 virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size, 90 unsigned ByteAlignment) { 91 report_fatal_error("unsupported directive in pure streamer"); 92 } 93 virtual void EmitFileDirective(StringRef Filename) { 94 report_fatal_error("unsupported directive in pure streamer"); 95 } 96 virtual bool EmitDwarfFileDirective(unsigned FileNo, StringRef Directory, 97 StringRef Filename, unsigned CUID = 0) { 98 report_fatal_error("unsupported directive in pure streamer"); 99 } 100 101 /// @} 102 103 static bool classof(const MCStreamer *S) { 104 return S->getKind() == SK_PureStreamer; 105 } 106 }; 107 108 } // end anonymous namespace. 109 110 void MCPureStreamer::InitSections() { 111 InitToTextSection(); 112 } 113 114 void MCPureStreamer::InitToTextSection() { 115 SwitchSection(getContext().getObjectFileInfo()->getTextSection()); 116 } 117 118 void MCPureStreamer::EmitLabel(MCSymbol *Symbol) { 119 assert(Symbol->isUndefined() && "Cannot define a symbol twice!"); 120 assert(!Symbol->isVariable() && "Cannot emit a variable symbol!"); 121 assert(getCurrentSection().first && "Cannot emit before setting section!"); 122 123 Symbol->setSection(*getCurrentSection().first); 124 125 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol); 126 127 // We have to create a new fragment if this is an atom defining symbol, 128 // fragments cannot span atoms. 129 if (getAssembler().isSymbolLinkerVisible(SD.getSymbol())) 130 insert(new MCDataFragment()); 131 132 // FIXME: This is wasteful, we don't necessarily need to create a data 133 // fragment. Instead, we should mark the symbol as pointing into the data 134 // fragment if it exists, otherwise we should just queue the label and set its 135 // fragment pointer when we emit the next fragment. 136 MCDataFragment *F = getOrCreateDataFragment(); 137 assert(!SD.getFragment() && "Unexpected fragment on symbol data!"); 138 SD.setFragment(F); 139 SD.setOffset(F->getContents().size()); 140 } 141 142 143 void MCPureStreamer::EmitDebugLabel(MCSymbol *Symbol) { 144 EmitLabel(Symbol); 145 } 146 147 void MCPureStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol, 148 uint64_t Size, unsigned ByteAlignment) { 149 report_fatal_error("not yet implemented in pure streamer"); 150 } 151 152 void MCPureStreamer::EmitBytes(StringRef Data) { 153 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into 154 // MCObjectStreamer. 155 getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end()); 156 } 157 158 void MCPureStreamer::EmitValueToAlignment(unsigned ByteAlignment, 159 int64_t Value, unsigned ValueSize, 160 unsigned MaxBytesToEmit) { 161 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into 162 // MCObjectStreamer. 163 if (MaxBytesToEmit == 0) 164 MaxBytesToEmit = ByteAlignment; 165 insert(new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit)); 166 167 // Update the maximum alignment on the current section if necessary. 168 if (ByteAlignment > getCurrentSectionData()->getAlignment()) 169 getCurrentSectionData()->setAlignment(ByteAlignment); 170 } 171 172 void MCPureStreamer::EmitCodeAlignment(unsigned ByteAlignment, 173 unsigned MaxBytesToEmit) { 174 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into 175 // MCObjectStreamer. 176 if (MaxBytesToEmit == 0) 177 MaxBytesToEmit = ByteAlignment; 178 MCAlignFragment *F = new MCAlignFragment(ByteAlignment, 0, 1, MaxBytesToEmit); 179 insert(F); 180 F->setEmitNops(true); 181 182 // Update the maximum alignment on the current section if necessary. 183 if (ByteAlignment > getCurrentSectionData()->getAlignment()) 184 getCurrentSectionData()->setAlignment(ByteAlignment); 185 } 186 187 bool MCPureStreamer::EmitValueToOffset(const MCExpr *Offset, 188 unsigned char Value) { 189 insert(new MCOrgFragment(*Offset, Value)); 190 return false; 191 } 192 193 void MCPureStreamer::EmitInstToFragment(const MCInst &Inst) { 194 MCRelaxableFragment *IF = new MCRelaxableFragment(Inst); 195 insert(IF); 196 197 // Add the fixups and data. 198 // 199 // FIXME: Revisit this design decision when relaxation is done, we may be 200 // able to get away with not storing any extra data in the MCInst. 201 SmallVector<MCFixup, 4> Fixups; 202 SmallString<256> Code; 203 raw_svector_ostream VecOS(Code); 204 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups); 205 VecOS.flush(); 206 207 IF->getContents() = Code; 208 IF->getFixups() = Fixups; 209 } 210 211 void MCPureStreamer::EmitInstToData(const MCInst &Inst) { 212 MCDataFragment *DF = getOrCreateDataFragment(); 213 214 SmallVector<MCFixup, 4> Fixups; 215 SmallString<256> Code; 216 raw_svector_ostream VecOS(Code); 217 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups); 218 VecOS.flush(); 219 220 // Add the fixups and data. 221 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) { 222 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size()); 223 DF->getFixups().push_back(Fixups[i]); 224 } 225 DF->getContents().append(Code.begin(), Code.end()); 226 } 227 228 void MCPureStreamer::FinishImpl() { 229 // FIXME: Handle DWARF tables? 230 231 this->MCObjectStreamer::FinishImpl(); 232 } 233 234 MCStreamer *llvm::createPureStreamer(MCContext &Context, MCAsmBackend &MAB, 235 raw_ostream &OS, MCCodeEmitter *CE) { 236 return new MCPureStreamer(Context, MAB, OS, CE); 237 } 238
