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, 32 raw_ostream &OS, MCCodeEmitter *Emitter) 33 : MCObjectStreamer(Context, TAB, OS, Emitter) {} 34 35 /// @name MCStreamer Interface 36 /// @{ 37 38 virtual void InitSections(); 39 virtual void EmitLabel(MCSymbol *Symbol); 40 virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value); 41 virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0, 42 unsigned Size = 0, unsigned ByteAlignment = 0); 43 virtual void EmitBytes(StringRef Data, unsigned AddrSpace); 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 void EmitValueToOffset(const MCExpr *Offset, 50 unsigned char Value = 0); 51 virtual void Finish(); 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 Filename) { 97 report_fatal_error("unsupported directive in pure streamer"); 98 return false; 99 } 100 101 /// @} 102 }; 103 104 } // end anonymous namespace. 105 106 void MCPureStreamer::InitSections() { 107 // FIMXE: To what!? 108 SwitchSection(getContext().getMachOSection("__TEXT", "__text", 109 MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS, 110 0, SectionKind::getText())); 111 112 } 113 114 void MCPureStreamer::EmitLabel(MCSymbol *Symbol) { 115 assert(Symbol->isUndefined() && "Cannot define a symbol twice!"); 116 assert(!Symbol->isVariable() && "Cannot emit a variable symbol!"); 117 assert(getCurrentSection() && "Cannot emit before setting section!"); 118 119 Symbol->setSection(*getCurrentSection()); 120 121 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol); 122 123 // We have to create a new fragment if this is an atom defining symbol, 124 // fragments cannot span atoms. 125 if (getAssembler().isSymbolLinkerVisible(SD.getSymbol())) 126 new MCDataFragment(getCurrentSectionData()); 127 128 // FIXME: This is wasteful, we don't necessarily need to create a data 129 // fragment. Instead, we should mark the symbol as pointing into the data 130 // fragment if it exists, otherwise we should just queue the label and set its 131 // fragment pointer when we emit the next fragment. 132 MCDataFragment *F = getOrCreateDataFragment(); 133 assert(!SD.getFragment() && "Unexpected fragment on symbol data!"); 134 SD.setFragment(F); 135 SD.setOffset(F->getContents().size()); 136 } 137 138 void MCPureStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) { 139 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into 140 // MCObjectStreamer. 141 // FIXME: Lift context changes into super class. 142 getAssembler().getOrCreateSymbolData(*Symbol); 143 Symbol->setVariableValue(AddValueSymbols(Value)); 144 } 145 146 void MCPureStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol, 147 unsigned Size, unsigned ByteAlignment) { 148 report_fatal_error("not yet implemented in pure streamer"); 149 } 150 151 void MCPureStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) { 152 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into 153 // MCObjectStreamer. 154 getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end()); 155 } 156 157 void MCPureStreamer::EmitValueToAlignment(unsigned ByteAlignment, 158 int64_t Value, unsigned ValueSize, 159 unsigned MaxBytesToEmit) { 160 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into 161 // MCObjectStreamer. 162 if (MaxBytesToEmit == 0) 163 MaxBytesToEmit = ByteAlignment; 164 new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit, 165 getCurrentSectionData()); 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 getCurrentSectionData()); 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 void MCPureStreamer::EmitValueToOffset(const MCExpr *Offset, 188 unsigned char Value) { 189 new MCOrgFragment(*Offset, Value, getCurrentSectionData()); 190 } 191 192 void MCPureStreamer::EmitInstToFragment(const MCInst &Inst) { 193 MCInstFragment *IF = new MCInstFragment(Inst, getCurrentSectionData()); 194 195 // Add the fixups and data. 196 // 197 // FIXME: Revisit this design decision when relaxation is done, we may be 198 // able to get away with not storing any extra data in the MCInst. 199 SmallVector<MCFixup, 4> Fixups; 200 SmallString<256> Code; 201 raw_svector_ostream VecOS(Code); 202 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups); 203 VecOS.flush(); 204 205 IF->getCode() = Code; 206 IF->getFixups() = Fixups; 207 } 208 209 void MCPureStreamer::EmitInstToData(const MCInst &Inst) { 210 MCDataFragment *DF = getOrCreateDataFragment(); 211 212 SmallVector<MCFixup, 4> Fixups; 213 SmallString<256> Code; 214 raw_svector_ostream VecOS(Code); 215 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups); 216 VecOS.flush(); 217 218 // Add the fixups and data. 219 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) { 220 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size()); 221 DF->addFixup(Fixups[i]); 222 } 223 DF->getContents().append(Code.begin(), Code.end()); 224 } 225 226 void MCPureStreamer::Finish() { 227 // FIXME: Handle DWARF tables? 228 229 this->MCObjectStreamer::Finish(); 230 } 231 232 MCStreamer *llvm::createPureStreamer(MCContext &Context, MCAsmBackend &MAB, 233 raw_ostream &OS, MCCodeEmitter *CE) { 234 return new MCPureStreamer(Context, MAB, OS, CE); 235 } 236
