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/MCObjectStreamer.h" 16 // FIXME: Remove this. 17 #include "llvm/MC/MCSectionMachO.h" 18 #include "llvm/MC/MCSymbol.h" 19 #include "llvm/Support/ErrorHandling.h" 20 21 using namespace llvm; 22 23 namespace { 24 25 class MCPureStreamer : public MCObjectStreamer { 26 private: 27 virtual void EmitInstToFragment(const MCInst &Inst); 28 virtual void EmitInstToData(const MCInst &Inst); 29 30 public: 31 MCPureStreamer(MCContext &Context, MCAsmBackend &TAB, raw_ostream &OS, 32 MCCodeEmitter *Emitter) 33 : MCObjectStreamer(SK_PureStreamer, Context, TAB, OS, Emitter) {} 34 35 /// @name MCStreamer Interface 36 /// @{ 37 38 virtual void InitSections(); 39 virtual void InitToTextSection(); 40 virtual void EmitLabel(MCSymbol *Symbol); 41 virtual void EmitDebugLabel(MCSymbol *Symbol); 42 virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0, 43 uint64_t Size = 0, unsigned ByteAlignment = 0); 44 virtual void EmitBytes(StringRef Data, unsigned AddrSpace); 45 virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0, 46 unsigned ValueSize = 1, 47 unsigned MaxBytesToEmit = 0); 48 virtual void EmitCodeAlignment(unsigned ByteAlignment, 49 unsigned MaxBytesToEmit = 0); 50 virtual bool EmitValueToOffset(const MCExpr *Offset, 51 unsigned char Value = 0); 52 virtual void FinishImpl(); 53 54 55 virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) { 56 report_fatal_error("unsupported directive in pure streamer"); 57 } 58 virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) { 59 report_fatal_error("unsupported directive in pure streamer"); 60 } 61 virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol, 62 uint64_t Size, unsigned ByteAlignment = 0) { 63 report_fatal_error("unsupported directive in pure streamer"); 64 } 65 virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) { 66 report_fatal_error("unsupported directive in pure streamer"); 67 } 68 virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size, 69 unsigned ByteAlignment) { 70 report_fatal_error("unsupported directive in pure streamer"); 71 } 72 virtual void EmitThumbFunc(MCSymbol *Func) { 73 report_fatal_error("unsupported directive in pure streamer"); 74 } 75 virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) { 76 report_fatal_error("unsupported directive in pure streamer"); 77 } 78 virtual void EmitCOFFSymbolStorageClass(int StorageClass) { 79 report_fatal_error("unsupported directive in pure streamer"); 80 } 81 virtual void EmitCOFFSymbolType(int Type) { 82 report_fatal_error("unsupported directive in pure streamer"); 83 } 84 virtual void EndCOFFSymbolDef() { 85 report_fatal_error("unsupported directive in pure streamer"); 86 } 87 virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) { 88 report_fatal_error("unsupported directive in pure streamer"); 89 } 90 virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size, 91 unsigned ByteAlignment) { 92 report_fatal_error("unsupported directive in pure streamer"); 93 } 94 virtual void EmitFileDirective(StringRef Filename) { 95 report_fatal_error("unsupported directive in pure streamer"); 96 } 97 virtual bool EmitDwarfFileDirective(unsigned FileNo, StringRef Directory, 98 StringRef Filename, unsigned CUID = 0) { 99 report_fatal_error("unsupported directive in pure streamer"); 100 } 101 102 /// @} 103 104 static bool classof(const MCStreamer *S) { 105 return S->getKind() == SK_PureStreamer; 106 } 107 }; 108 109 } // end anonymous namespace. 110 111 void MCPureStreamer::InitSections() { 112 InitToTextSection(); 113 } 114 115 void MCPureStreamer::InitToTextSection() { 116 // FIMXE: To what!? 117 SwitchSection(getContext().getMachOSection("__TEXT", "__text", 118 MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS, 119 0, SectionKind::getText())); 120 } 121 122 void MCPureStreamer::EmitLabel(MCSymbol *Symbol) { 123 assert(Symbol->isUndefined() && "Cannot define a symbol twice!"); 124 assert(!Symbol->isVariable() && "Cannot emit a variable symbol!"); 125 assert(getCurrentSection() && "Cannot emit before setting section!"); 126 127 Symbol->setSection(*getCurrentSection()); 128 129 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol); 130 131 // We have to create a new fragment if this is an atom defining symbol, 132 // fragments cannot span atoms. 133 if (getAssembler().isSymbolLinkerVisible(SD.getSymbol())) 134 new MCDataFragment(getCurrentSectionData()); 135 136 // FIXME: This is wasteful, we don't necessarily need to create a data 137 // fragment. Instead, we should mark the symbol as pointing into the data 138 // fragment if it exists, otherwise we should just queue the label and set its 139 // fragment pointer when we emit the next fragment. 140 MCDataFragment *F = getOrCreateDataFragment(); 141 assert(!SD.getFragment() && "Unexpected fragment on symbol data!"); 142 SD.setFragment(F); 143 SD.setOffset(F->getContents().size()); 144 } 145 146 147 void MCPureStreamer::EmitDebugLabel(MCSymbol *Symbol) { 148 EmitLabel(Symbol); 149 } 150 151 void MCPureStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol, 152 uint64_t Size, unsigned ByteAlignment) { 153 report_fatal_error("not yet implemented in pure streamer"); 154 } 155 156 void MCPureStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) { 157 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into 158 // MCObjectStreamer. 159 getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end()); 160 } 161 162 void MCPureStreamer::EmitValueToAlignment(unsigned ByteAlignment, 163 int64_t Value, unsigned ValueSize, 164 unsigned MaxBytesToEmit) { 165 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into 166 // MCObjectStreamer. 167 if (MaxBytesToEmit == 0) 168 MaxBytesToEmit = ByteAlignment; 169 new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit, 170 getCurrentSectionData()); 171 172 // Update the maximum alignment on the current section if necessary. 173 if (ByteAlignment > getCurrentSectionData()->getAlignment()) 174 getCurrentSectionData()->setAlignment(ByteAlignment); 175 } 176 177 void MCPureStreamer::EmitCodeAlignment(unsigned ByteAlignment, 178 unsigned MaxBytesToEmit) { 179 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into 180 // MCObjectStreamer. 181 if (MaxBytesToEmit == 0) 182 MaxBytesToEmit = ByteAlignment; 183 MCAlignFragment *F = new MCAlignFragment(ByteAlignment, 0, 1, MaxBytesToEmit, 184 getCurrentSectionData()); 185 F->setEmitNops(true); 186 187 // Update the maximum alignment on the current section if necessary. 188 if (ByteAlignment > getCurrentSectionData()->getAlignment()) 189 getCurrentSectionData()->setAlignment(ByteAlignment); 190 } 191 192 bool MCPureStreamer::EmitValueToOffset(const MCExpr *Offset, 193 unsigned char Value) { 194 new MCOrgFragment(*Offset, Value, getCurrentSectionData()); 195 return false; 196 } 197 198 void MCPureStreamer::EmitInstToFragment(const MCInst &Inst) { 199 MCRelaxableFragment *IF = 200 new MCRelaxableFragment(Inst, getCurrentSectionData()); 201 202 // Add the fixups and data. 203 // 204 // FIXME: Revisit this design decision when relaxation is done, we may be 205 // able to get away with not storing any extra data in the MCInst. 206 SmallVector<MCFixup, 4> Fixups; 207 SmallString<256> Code; 208 raw_svector_ostream VecOS(Code); 209 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups); 210 VecOS.flush(); 211 212 IF->getContents() = Code; 213 IF->getFixups() = Fixups; 214 } 215 216 void MCPureStreamer::EmitInstToData(const MCInst &Inst) { 217 MCDataFragment *DF = getOrCreateDataFragment(); 218 219 SmallVector<MCFixup, 4> Fixups; 220 SmallString<256> Code; 221 raw_svector_ostream VecOS(Code); 222 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups); 223 VecOS.flush(); 224 225 // Add the fixups and data. 226 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) { 227 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size()); 228 DF->getFixups().push_back(Fixups[i]); 229 } 230 DF->getContents().append(Code.begin(), Code.end()); 231 } 232 233 void MCPureStreamer::FinishImpl() { 234 // FIXME: Handle DWARF tables? 235 236 this->MCObjectStreamer::FinishImpl(); 237 } 238 239 MCStreamer *llvm::createPureStreamer(MCContext &Context, MCAsmBackend &MAB, 240 raw_ostream &OS, MCCodeEmitter *CE) { 241 return new MCPureStreamer(Context, MAB, OS, CE); 242 } 243
