1 //===-- MachODump.cpp - Object file dumping utility for llvm --------------===// 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 // This file implements the MachO-specific dumper for llvm-objdump. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm-objdump.h" 15 #include "llvm/ADT/STLExtras.h" 16 #include "llvm/ADT/StringExtras.h" 17 #include "llvm/ADT/Triple.h" 18 #include "llvm/DebugInfo/DIContext.h" 19 #include "llvm/MC/MCAsmInfo.h" 20 #include "llvm/MC/MCContext.h" 21 #include "llvm/MC/MCDisassembler.h" 22 #include "llvm/MC/MCInst.h" 23 #include "llvm/MC/MCInstPrinter.h" 24 #include "llvm/MC/MCInstrAnalysis.h" 25 #include "llvm/MC/MCInstrDesc.h" 26 #include "llvm/MC/MCInstrInfo.h" 27 #include "llvm/MC/MCRegisterInfo.h" 28 #include "llvm/MC/MCSubtargetInfo.h" 29 #include "llvm/Object/MachO.h" 30 #include "llvm/Support/Casting.h" 31 #include "llvm/Support/CommandLine.h" 32 #include "llvm/Support/Debug.h" 33 #include "llvm/Support/Format.h" 34 #include "llvm/Support/GraphWriter.h" 35 #include "llvm/Support/MachO.h" 36 #include "llvm/Support/MemoryBuffer.h" 37 #include "llvm/Support/TargetRegistry.h" 38 #include "llvm/Support/TargetSelect.h" 39 #include "llvm/Support/raw_ostream.h" 40 #include <algorithm> 41 #include <cstring> 42 #include <system_error> 43 using namespace llvm; 44 using namespace object; 45 46 static cl::opt<bool> 47 UseDbg("g", cl::desc("Print line information from debug info if available")); 48 49 static cl::opt<std::string> 50 DSYMFile("dsym", cl::desc("Use .dSYM file for debug info")); 51 52 static const Target *GetTarget(const MachOObjectFile *MachOObj) { 53 // Figure out the target triple. 54 if (TripleName.empty()) { 55 llvm::Triple TT("unknown-unknown-unknown"); 56 TT.setArch(Triple::ArchType(MachOObj->getArch())); 57 TripleName = TT.str(); 58 } 59 60 // Get the target specific parser. 61 std::string Error; 62 const Target *TheTarget = TargetRegistry::lookupTarget(TripleName, Error); 63 if (TheTarget) 64 return TheTarget; 65 66 errs() << "llvm-objdump: error: unable to get target for '" << TripleName 67 << "', see --version and --triple.\n"; 68 return nullptr; 69 } 70 71 struct SymbolSorter { 72 bool operator()(const SymbolRef &A, const SymbolRef &B) { 73 SymbolRef::Type AType, BType; 74 A.getType(AType); 75 B.getType(BType); 76 77 uint64_t AAddr, BAddr; 78 if (AType != SymbolRef::ST_Function) 79 AAddr = 0; 80 else 81 A.getAddress(AAddr); 82 if (BType != SymbolRef::ST_Function) 83 BAddr = 0; 84 else 85 B.getAddress(BAddr); 86 return AAddr < BAddr; 87 } 88 }; 89 90 // Types for the storted data in code table that is built before disassembly 91 // and the predicate function to sort them. 92 typedef std::pair<uint64_t, DiceRef> DiceTableEntry; 93 typedef std::vector<DiceTableEntry> DiceTable; 94 typedef DiceTable::iterator dice_table_iterator; 95 96 static bool 97 compareDiceTableEntries(const DiceTableEntry i, 98 const DiceTableEntry j) { 99 return i.first == j.first; 100 } 101 102 static void DumpDataInCode(const char *bytes, uint64_t Size, 103 unsigned short Kind) { 104 uint64_t Value; 105 106 switch (Kind) { 107 case MachO::DICE_KIND_DATA: 108 switch (Size) { 109 case 4: 110 Value = bytes[3] << 24 | 111 bytes[2] << 16 | 112 bytes[1] << 8 | 113 bytes[0]; 114 outs() << "\t.long " << Value; 115 break; 116 case 2: 117 Value = bytes[1] << 8 | 118 bytes[0]; 119 outs() << "\t.short " << Value; 120 break; 121 case 1: 122 Value = bytes[0]; 123 outs() << "\t.byte " << Value; 124 break; 125 } 126 outs() << "\t@ KIND_DATA\n"; 127 break; 128 case MachO::DICE_KIND_JUMP_TABLE8: 129 Value = bytes[0]; 130 outs() << "\t.byte " << Value << "\t@ KIND_JUMP_TABLE8"; 131 break; 132 case MachO::DICE_KIND_JUMP_TABLE16: 133 Value = bytes[1] << 8 | 134 bytes[0]; 135 outs() << "\t.short " << Value << "\t@ KIND_JUMP_TABLE16"; 136 break; 137 case MachO::DICE_KIND_JUMP_TABLE32: 138 Value = bytes[3] << 24 | 139 bytes[2] << 16 | 140 bytes[1] << 8 | 141 bytes[0]; 142 outs() << "\t.long " << Value << "\t@ KIND_JUMP_TABLE32"; 143 break; 144 default: 145 outs() << "\t@ data in code kind = " << Kind << "\n"; 146 break; 147 } 148 } 149 150 static void getSectionsAndSymbols(const MachO::mach_header Header, 151 MachOObjectFile *MachOObj, 152 std::vector<SectionRef> &Sections, 153 std::vector<SymbolRef> &Symbols, 154 SmallVectorImpl<uint64_t> &FoundFns, 155 uint64_t &BaseSegmentAddress) { 156 for (const SymbolRef &Symbol : MachOObj->symbols()) 157 Symbols.push_back(Symbol); 158 159 for (const SectionRef &Section : MachOObj->sections()) { 160 StringRef SectName; 161 Section.getName(SectName); 162 Sections.push_back(Section); 163 } 164 165 MachOObjectFile::LoadCommandInfo Command = 166 MachOObj->getFirstLoadCommandInfo(); 167 bool BaseSegmentAddressSet = false; 168 for (unsigned i = 0; ; ++i) { 169 if (Command.C.cmd == MachO::LC_FUNCTION_STARTS) { 170 // We found a function starts segment, parse the addresses for later 171 // consumption. 172 MachO::linkedit_data_command LLC = 173 MachOObj->getLinkeditDataLoadCommand(Command); 174 175 MachOObj->ReadULEB128s(LLC.dataoff, FoundFns); 176 } 177 else if (Command.C.cmd == MachO::LC_SEGMENT) { 178 MachO::segment_command SLC = 179 MachOObj->getSegmentLoadCommand(Command); 180 StringRef SegName = SLC.segname; 181 if(!BaseSegmentAddressSet && SegName != "__PAGEZERO") { 182 BaseSegmentAddressSet = true; 183 BaseSegmentAddress = SLC.vmaddr; 184 } 185 } 186 187 if (i == Header.ncmds - 1) 188 break; 189 else 190 Command = MachOObj->getNextLoadCommandInfo(Command); 191 } 192 } 193 194 static void DisassembleInputMachO2(StringRef Filename, 195 MachOObjectFile *MachOOF); 196 197 void llvm::DisassembleInputMachO(StringRef Filename) { 198 ErrorOr<std::unique_ptr<MemoryBuffer>> Buff = 199 MemoryBuffer::getFileOrSTDIN(Filename); 200 if (std::error_code EC = Buff.getError()) { 201 errs() << "llvm-objdump: " << Filename << ": " << EC.message() << "\n"; 202 return; 203 } 204 205 std::unique_ptr<MachOObjectFile> MachOOF(static_cast<MachOObjectFile *>( 206 ObjectFile::createMachOObjectFile(Buff.get()).get())); 207 208 DisassembleInputMachO2(Filename, MachOOF.get()); 209 } 210 211 static void DisassembleInputMachO2(StringRef Filename, 212 MachOObjectFile *MachOOF) { 213 const Target *TheTarget = GetTarget(MachOOF); 214 if (!TheTarget) { 215 // GetTarget prints out stuff. 216 return; 217 } 218 std::unique_ptr<const MCInstrInfo> InstrInfo(TheTarget->createMCInstrInfo()); 219 std::unique_ptr<MCInstrAnalysis> InstrAnalysis( 220 TheTarget->createMCInstrAnalysis(InstrInfo.get())); 221 222 // Set up disassembler. 223 std::unique_ptr<const MCRegisterInfo> MRI( 224 TheTarget->createMCRegInfo(TripleName)); 225 std::unique_ptr<const MCAsmInfo> AsmInfo( 226 TheTarget->createMCAsmInfo(*MRI, TripleName)); 227 std::unique_ptr<const MCSubtargetInfo> STI( 228 TheTarget->createMCSubtargetInfo(TripleName, "", "")); 229 MCContext Ctx(AsmInfo.get(), MRI.get(), nullptr); 230 std::unique_ptr<const MCDisassembler> DisAsm( 231 TheTarget->createMCDisassembler(*STI, Ctx)); 232 int AsmPrinterVariant = AsmInfo->getAssemblerDialect(); 233 std::unique_ptr<MCInstPrinter> IP(TheTarget->createMCInstPrinter( 234 AsmPrinterVariant, *AsmInfo, *InstrInfo, *MRI, *STI)); 235 236 if (!InstrAnalysis || !AsmInfo || !STI || !DisAsm || !IP) { 237 errs() << "error: couldn't initialize disassembler for target " 238 << TripleName << '\n'; 239 return; 240 } 241 242 outs() << '\n' << Filename << ":\n\n"; 243 244 MachO::mach_header Header = MachOOF->getHeader(); 245 246 // FIXME: FoundFns isn't used anymore. Using symbols/LC_FUNCTION_STARTS to 247 // determine function locations will eventually go in MCObjectDisassembler. 248 // FIXME: Using the -cfg command line option, this code used to be able to 249 // annotate relocations with the referenced symbol's name, and if this was 250 // inside a __[cf]string section, the data it points to. This is now replaced 251 // by the upcoming MCSymbolizer, which needs the appropriate setup done above. 252 std::vector<SectionRef> Sections; 253 std::vector<SymbolRef> Symbols; 254 SmallVector<uint64_t, 8> FoundFns; 255 uint64_t BaseSegmentAddress; 256 257 getSectionsAndSymbols(Header, MachOOF, Sections, Symbols, FoundFns, 258 BaseSegmentAddress); 259 260 // Sort the symbols by address, just in case they didn't come in that way. 261 std::sort(Symbols.begin(), Symbols.end(), SymbolSorter()); 262 263 // Build a data in code table that is sorted on by the address of each entry. 264 uint64_t BaseAddress = 0; 265 if (Header.filetype == MachO::MH_OBJECT) 266 Sections[0].getAddress(BaseAddress); 267 else 268 BaseAddress = BaseSegmentAddress; 269 DiceTable Dices; 270 for (dice_iterator DI = MachOOF->begin_dices(), DE = MachOOF->end_dices(); 271 DI != DE; ++DI) { 272 uint32_t Offset; 273 DI->getOffset(Offset); 274 Dices.push_back(std::make_pair(BaseAddress + Offset, *DI)); 275 } 276 array_pod_sort(Dices.begin(), Dices.end()); 277 278 #ifndef NDEBUG 279 raw_ostream &DebugOut = DebugFlag ? dbgs() : nulls(); 280 #else 281 raw_ostream &DebugOut = nulls(); 282 #endif 283 284 std::unique_ptr<DIContext> diContext; 285 ObjectFile *DbgObj = MachOOF; 286 // Try to find debug info and set up the DIContext for it. 287 if (UseDbg) { 288 // A separate DSym file path was specified, parse it as a macho file, 289 // get the sections and supply it to the section name parsing machinery. 290 if (!DSYMFile.empty()) { 291 ErrorOr<std::unique_ptr<MemoryBuffer>> Buf = 292 MemoryBuffer::getFileOrSTDIN(DSYMFile); 293 if (std::error_code EC = Buf.getError()) { 294 errs() << "llvm-objdump: " << Filename << ": " << EC.message() << '\n'; 295 return; 296 } 297 DbgObj = ObjectFile::createMachOObjectFile(Buf.get()).get(); 298 } 299 300 // Setup the DIContext 301 diContext.reset(DIContext::getDWARFContext(DbgObj)); 302 } 303 304 for (unsigned SectIdx = 0; SectIdx != Sections.size(); SectIdx++) { 305 306 bool SectIsText = false; 307 Sections[SectIdx].isText(SectIsText); 308 if (SectIsText == false) 309 continue; 310 311 StringRef SectName; 312 if (Sections[SectIdx].getName(SectName) || 313 SectName != "__text") 314 continue; // Skip non-text sections 315 316 DataRefImpl DR = Sections[SectIdx].getRawDataRefImpl(); 317 318 StringRef SegmentName = MachOOF->getSectionFinalSegmentName(DR); 319 if (SegmentName != "__TEXT") 320 continue; 321 322 StringRef Bytes; 323 Sections[SectIdx].getContents(Bytes); 324 StringRefMemoryObject memoryObject(Bytes); 325 bool symbolTableWorked = false; 326 327 // Parse relocations. 328 std::vector<std::pair<uint64_t, SymbolRef>> Relocs; 329 for (const RelocationRef &Reloc : Sections[SectIdx].relocations()) { 330 uint64_t RelocOffset, SectionAddress; 331 Reloc.getOffset(RelocOffset); 332 Sections[SectIdx].getAddress(SectionAddress); 333 RelocOffset -= SectionAddress; 334 335 symbol_iterator RelocSym = Reloc.getSymbol(); 336 337 Relocs.push_back(std::make_pair(RelocOffset, *RelocSym)); 338 } 339 array_pod_sort(Relocs.begin(), Relocs.end()); 340 341 // Disassemble symbol by symbol. 342 for (unsigned SymIdx = 0; SymIdx != Symbols.size(); SymIdx++) { 343 StringRef SymName; 344 Symbols[SymIdx].getName(SymName); 345 346 SymbolRef::Type ST; 347 Symbols[SymIdx].getType(ST); 348 if (ST != SymbolRef::ST_Function) 349 continue; 350 351 // Make sure the symbol is defined in this section. 352 bool containsSym = false; 353 Sections[SectIdx].containsSymbol(Symbols[SymIdx], containsSym); 354 if (!containsSym) 355 continue; 356 357 // Start at the address of the symbol relative to the section's address. 358 uint64_t SectionAddress = 0; 359 uint64_t Start = 0; 360 Sections[SectIdx].getAddress(SectionAddress); 361 Symbols[SymIdx].getAddress(Start); 362 Start -= SectionAddress; 363 364 // Stop disassembling either at the beginning of the next symbol or at 365 // the end of the section. 366 bool containsNextSym = false; 367 uint64_t NextSym = 0; 368 uint64_t NextSymIdx = SymIdx+1; 369 while (Symbols.size() > NextSymIdx) { 370 SymbolRef::Type NextSymType; 371 Symbols[NextSymIdx].getType(NextSymType); 372 if (NextSymType == SymbolRef::ST_Function) { 373 Sections[SectIdx].containsSymbol(Symbols[NextSymIdx], 374 containsNextSym); 375 Symbols[NextSymIdx].getAddress(NextSym); 376 NextSym -= SectionAddress; 377 break; 378 } 379 ++NextSymIdx; 380 } 381 382 uint64_t SectSize; 383 Sections[SectIdx].getSize(SectSize); 384 uint64_t End = containsNextSym ? NextSym : SectSize; 385 uint64_t Size; 386 387 symbolTableWorked = true; 388 389 outs() << SymName << ":\n"; 390 DILineInfo lastLine; 391 for (uint64_t Index = Start; Index < End; Index += Size) { 392 MCInst Inst; 393 394 uint64_t SectAddress = 0; 395 Sections[SectIdx].getAddress(SectAddress); 396 outs() << format("%8" PRIx64 ":\t", SectAddress + Index); 397 398 // Check the data in code table here to see if this is data not an 399 // instruction to be disassembled. 400 DiceTable Dice; 401 Dice.push_back(std::make_pair(SectAddress + Index, DiceRef())); 402 dice_table_iterator DTI = std::search(Dices.begin(), Dices.end(), 403 Dice.begin(), Dice.end(), 404 compareDiceTableEntries); 405 if (DTI != Dices.end()){ 406 uint16_t Length; 407 DTI->second.getLength(Length); 408 DumpBytes(StringRef(Bytes.data() + Index, Length)); 409 uint16_t Kind; 410 DTI->second.getKind(Kind); 411 DumpDataInCode(Bytes.data() + Index, Length, Kind); 412 continue; 413 } 414 415 if (DisAsm->getInstruction(Inst, Size, memoryObject, Index, 416 DebugOut, nulls())) { 417 DumpBytes(StringRef(Bytes.data() + Index, Size)); 418 IP->printInst(&Inst, outs(), ""); 419 420 // Print debug info. 421 if (diContext) { 422 DILineInfo dli = 423 diContext->getLineInfoForAddress(SectAddress + Index); 424 // Print valid line info if it changed. 425 if (dli != lastLine && dli.Line != 0) 426 outs() << "\t## " << dli.FileName << ':' << dli.Line << ':' 427 << dli.Column; 428 lastLine = dli; 429 } 430 outs() << "\n"; 431 } else { 432 errs() << "llvm-objdump: warning: invalid instruction encoding\n"; 433 if (Size == 0) 434 Size = 1; // skip illegible bytes 435 } 436 } 437 } 438 if (!symbolTableWorked) { 439 // Reading the symbol table didn't work, disassemble the whole section. 440 uint64_t SectAddress; 441 Sections[SectIdx].getAddress(SectAddress); 442 uint64_t SectSize; 443 Sections[SectIdx].getSize(SectSize); 444 uint64_t InstSize; 445 for (uint64_t Index = 0; Index < SectSize; Index += InstSize) { 446 MCInst Inst; 447 448 if (DisAsm->getInstruction(Inst, InstSize, memoryObject, Index, 449 DebugOut, nulls())) { 450 outs() << format("%8" PRIx64 ":\t", SectAddress + Index); 451 DumpBytes(StringRef(Bytes.data() + Index, InstSize)); 452 IP->printInst(&Inst, outs(), ""); 453 outs() << "\n"; 454 } else { 455 errs() << "llvm-objdump: warning: invalid instruction encoding\n"; 456 if (InstSize == 0) 457 InstSize = 1; // skip illegible bytes 458 } 459 } 460 } 461 } 462 } 463
