tools/llvm-objdump/MachODump.cpp

   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 "MCFunction.h"
  16 #include "llvm/Support/MachO.h"
  17 #include "llvm/Object/MachOObject.h"
  18 #include "llvm/ADT/OwningPtr.h"
  19 #include "llvm/ADT/Triple.h"
  20 #include "llvm/ADT/STLExtras.h"
  21 #include "llvm/MC/MCAsmInfo.h"
  22 #include "llvm/MC/MCDisassembler.h"
  23 #include "llvm/MC/MCInst.h"
  24 #include "llvm/MC/MCInstPrinter.h"
  25 #include "llvm/MC/MCInstrAnalysis.h"
  26 #include "llvm/MC/MCInstrDesc.h"
  27 #include "llvm/MC/MCInstrInfo.h"
  28 #include "llvm/MC/MCSubtargetInfo.h"
  29 #include "llvm/Support/CommandLine.h"
  30 #include "llvm/Support/Debug.h"
  31 #include "llvm/Support/Format.h"
  32 #include "llvm/Support/GraphWriter.h"
  33 #include "llvm/Support/MemoryBuffer.h"
  34 #include "llvm/Support/TargetRegistry.h"
  35 #include "llvm/Support/TargetSelect.h"
  36 #include "llvm/Support/raw_ostream.h"
  37 #include "llvm/Support/system_error.h"
  38 #include <algorithm>
  39 #include <cstring>
  40 using namespace llvm;
  41 using namespace object;
  42
  43 static cl::opt<bool>
  44   CFG("cfg", cl::desc("Create a CFG for every symbol in the object file and"
  45                       "write it to a graphviz file (MachO-only)"));
  46
  47 static const Target *GetTarget(const MachOObject *MachOObj) {
  48   // Figure out the target triple.
  49   llvm::Triple TT("unknown-unknown-unknown");
  50   switch (MachOObj->getHeader().CPUType) {
  51   case llvm::MachO::CPUTypeI386:
  52     TT.setArch(Triple::ArchType(Triple::x86));
  53     break;
  54   case llvm::MachO::CPUTypeX86_64:
  55     TT.setArch(Triple::ArchType(Triple::x86_64));
  56     break;
  57   case llvm::MachO::CPUTypeARM:
  58     TT.setArch(Triple::ArchType(Triple::arm));
  59     break;
  60   case llvm::MachO::CPUTypePowerPC:
  61     TT.setArch(Triple::ArchType(Triple::ppc));
  62     break;
  63   case llvm::MachO::CPUTypePowerPC64:
  64     TT.setArch(Triple::ArchType(Triple::ppc64));
  65     break;
  66   }
  67
  68   TripleName = TT.str();
  69
  70   // Get the target specific parser.
  71   std::string Error;
  72   const Target *TheTarget = TargetRegistry::lookupTarget(TripleName, Error);
  73   if (TheTarget)
  74     return TheTarget;
  75
  76   errs() << "llvm-objdump: error: unable to get target for '" << TripleName
  77          << "', see --version and --triple.\n";
  78   return 0;
  79 }
  80
  81 struct Section {
  82   char Name[16];
  83   uint64_t Address;
  84   uint64_t Size;
  85   uint32_t Offset;
  86   uint32_t NumRelocs;
  87   uint64_t RelocTableOffset;
  88 };
  89
  90 struct Symbol {
  91   uint64_t Value;
  92   uint32_t StringIndex;
  93   uint8_t SectionIndex;
  94   bool operator<(const Symbol &RHS) const { return Value < RHS.Value; }
  95 };
  96
  97 static void DumpAddress(uint64_t Address, ArrayRef<Section> Sections,
  98                         MachOObject *MachOObj, raw_ostream &OS) {
  99   for (unsigned i = 0; i != Sections.size(); ++i) {
 100     uint64_t addr = Address-Sections[i].Address;
 101     if (Sections[i].Address <= Address &&
 102         Sections[i].Address + Sections[i].Size > Address) {
 103       StringRef bytes = MachOObj->getData(Sections[i].Offset,
 104                                           Sections[i].Size);
 105       if (!strcmp(Sections[i].Name, "__cstring"))
 106         OS << '"' << bytes.substr(addr, bytes.find('\0', addr)) << '"';
 107       if (!strcmp(Sections[i].Name, "__cfstring"))
 108         OS << "@\"" << bytes.substr(addr, bytes.find('\0', addr)) << '"';
 109     }
 110   }
 111 }
 112
 113 void llvm::DisassembleInputMachO(StringRef Filename) {
 114   OwningPtr<MemoryBuffer> Buff;
 115
 116   if (error_code ec = MemoryBuffer::getFileOrSTDIN(Filename, Buff)) {
 117     errs() << "llvm-objdump: " << Filename << ": " << ec.message() << "\n";
 118     return;
 119   }
 120
 121   OwningPtr<MachOObject> MachOObj(MachOObject::LoadFromBuffer(Buff.take()));
 122
 123   const Target *TheTarget = GetTarget(MachOObj.get());
 124   if (!TheTarget) {
 125     // GetTarget prints out stuff.
 126     return;
 127   }
 128   const MCInstrInfo *InstrInfo = TheTarget->createMCInstrInfo();
 129   OwningPtr<MCInstrAnalysis>
 130     InstrAnalysis(TheTarget->createMCInstrAnalysis(InstrInfo));
 131
 132   // Set up disassembler.
 133   OwningPtr<const MCAsmInfo> AsmInfo(TheTarget->createMCAsmInfo(TripleName));
 134
 135   if (!AsmInfo) {
 136     errs() << "error: no assembly info for target " << TripleName << "\n";
 137     return;
 138   }
 139
 140   OwningPtr<const MCSubtargetInfo>
 141     STI(TheTarget->createMCSubtargetInfo(TripleName, "", ""));
 142
 143   if (!STI) {
 144     errs() << "error: no subtarget info for target " << TripleName << "\n";
 145     return;
 146   }
 147
 148   OwningPtr<const MCDisassembler> DisAsm(TheTarget->createMCDisassembler(*STI));
 149   if (!DisAsm) {
 150     errs() << "error: no disassembler for target " << TripleName << "\n";
 151     return;
 152   }
 153
 154   int AsmPrinterVariant = AsmInfo->getAssemblerDialect();
 155   OwningPtr<MCInstPrinter> IP(TheTarget->createMCInstPrinter(
 156         AsmPrinterVariant, *AsmInfo, *STI));
 157   if (!IP) {
 158     errs() << "error: no instruction printer for target " << TripleName << '\n';
 159     return;
 160   }
 161
 162   outs() << '\n';
 163   outs() << Filename << ":\n\n";
 164
 165   const macho::Header &Header = MachOObj->getHeader();
 166
 167   const MachOObject::LoadCommandInfo *SymtabLCI = 0;
 168   for (unsigned i = 0; i != Header.NumLoadCommands; ++i) {
 169     const MachOObject::LoadCommandInfo &LCI = MachOObj->getLoadCommandInfo(i);
 170     switch (LCI.Command.Type) {
 171     case macho::LCT_Symtab:
 172       SymtabLCI = &LCI;
 173       break;
 174     }
 175   }
 176
 177   // Read and register the symbol table data.
 178   InMemoryStruct<macho::SymtabLoadCommand> SymtabLC;
 179   MachOObj->ReadSymtabLoadCommand(*SymtabLCI, SymtabLC);
 180   MachOObj->RegisterStringTable(*SymtabLC);
 181
 182   std::vector<Section> Sections;
 183   std::vector<Symbol> Symbols;
 184   std::vector<Symbol> UnsortedSymbols; // FIXME: duplication
 185   SmallVector<uint64_t, 8> FoundFns;
 186
 187   for (unsigned i = 0; i != Header.NumLoadCommands; ++i) {
 188     const MachOObject::LoadCommandInfo &LCI = MachOObj->getLoadCommandInfo(i);
 189     if (LCI.Command.Type == macho::LCT_Segment) {
 190       InMemoryStruct<macho::SegmentLoadCommand> SegmentLC;
 191       MachOObj->ReadSegmentLoadCommand(LCI, SegmentLC);
 192
 193       for (unsigned SectNum = 0; SectNum != SegmentLC->NumSections; ++SectNum) {
 194         InMemoryStruct<macho::Section> Sect;
 195         MachOObj->ReadSection(LCI, SectNum, Sect);
 196
 197         Section S;
 198         memcpy(S.Name, Sect->Name, 16);
 199         S.Address = Sect->Address;
 200         S.Size = Sect->Size;
 201         S.Offset = Sect->Offset;
 202         S.NumRelocs = Sect->NumRelocationTableEntries;
 203         S.RelocTableOffset = Sect->RelocationTableOffset;
 204         Sections.push_back(S);
 205
 206         for (unsigned i = 0; i != SymtabLC->NumSymbolTableEntries; ++i) {
 207           InMemoryStruct<macho::SymbolTableEntry> STE;
 208           MachOObj->ReadSymbolTableEntry(SymtabLC->SymbolTableOffset, i, STE);
 209
 210           Symbol S;
 211           S.StringIndex = STE->StringIndex;
 212           S.SectionIndex = STE->SectionIndex;
 213           S.Value = STE->Value;
 214           Symbols.push_back(S);
 215           UnsortedSymbols.push_back(Symbols.back());
 216         }
 217       }
 218     } else if (LCI.Command.Type == macho::LCT_Segment64) {
 219       InMemoryStruct<macho::Segment64LoadCommand> Segment64LC;
 220       MachOObj->ReadSegment64LoadCommand(LCI, Segment64LC);
 221
 222       for (unsigned SectNum = 0; SectNum != Segment64LC->NumSections; ++SectNum) {
 223         InMemoryStruct<macho::Section64> Sect64;
 224         MachOObj->ReadSection64(LCI, SectNum, Sect64);
 225
 226         Section S;
 227         memcpy(S.Name, Sect64->Name, 16);
 228         S.Address = Sect64->Address;
 229         S.Size = Sect64->Size;
 230         S.Offset = Sect64->Offset;
 231         S.NumRelocs = Sect64->NumRelocationTableEntries;
 232         S.RelocTableOffset = Sect64->RelocationTableOffset;
 233         Sections.push_back(S);
 234
 235         for (unsigned i = 0; i != SymtabLC->NumSymbolTableEntries; ++i) {
 236           InMemoryStruct<macho::Symbol64TableEntry> STE;
 237           MachOObj->ReadSymbol64TableEntry(SymtabLC->SymbolTableOffset, i, STE);
 238
 239           Symbol S;
 240           S.StringIndex = STE->StringIndex;
 241           S.SectionIndex = STE->SectionIndex;
 242           S.Value = STE->Value;
 243           Symbols.push_back(S);
 244           UnsortedSymbols.push_back(Symbols.back());
 245         }
 246       }
 247     } else if (LCI.Command.Type == macho::LCT_FunctionStarts) {
 248       InMemoryStruct<macho::LinkeditDataLoadCommand> LLC;
 249       MachOObj->ReadLinkeditDataLoadCommand(LCI, LLC);
 250
 251       MachOObj->ReadULEB128s(LLC->DataOffset, FoundFns);
 252     }
 253   }
 254
 255   std::map<uint64_t, MCFunction*> FunctionMap;
 256
 257   // Sort the symbols by address, just in case they didn't come in that way.
 258   array_pod_sort(Symbols.begin(), Symbols.end());
 259
 260 #ifndef NDEBUG
 261   raw_ostream &DebugOut = DebugFlag ? dbgs() : nulls();
 262 #else
 263   raw_ostream &DebugOut = nulls();
 264 #endif
 265
 266   SmallVector<MCFunction, 16> Functions;
 267
 268   for (unsigned SectIdx = 0; SectIdx != Sections.size(); SectIdx++) {
 269     if (strcmp(Sections[SectIdx].Name, "__text"))
 270       continue;
 271
 272     uint64_t VMAddr = Sections[SectIdx].Address - Sections[SectIdx].Offset;
 273     for (unsigned i = 0, e = FoundFns.size(); i != e; ++i)
 274       FunctionMap.insert(std::make_pair(FoundFns[i]+VMAddr, (MCFunction*)0));
 275
 276     StringRef Bytes = MachOObj->getData(Sections[SectIdx].Offset,
 277                                         Sections[SectIdx].Size);
 278     StringRefMemoryObject memoryObject(Bytes);
 279     bool symbolTableWorked = false;
 280
 281     std::vector<std::pair<uint64_t, uint32_t> > Relocs;
 282     for (unsigned j = 0; j != Sections[SectIdx].NumRelocs; ++j) {
 283       InMemoryStruct<macho::RelocationEntry> RE;
 284       MachOObj->ReadRelocationEntry(Sections[SectIdx].RelocTableOffset, j, RE);
 285       Relocs.push_back(std::make_pair(RE->Word0, RE->Word1 & 0xffffff));
 286     }
 287     array_pod_sort(Relocs.begin(), Relocs.end());
 288
 289     for (unsigned SymIdx = 0; SymIdx != Symbols.size(); SymIdx++) {
 290       if ((unsigned)Symbols[SymIdx].SectionIndex - 1 != SectIdx)
 291         continue;
 292
 293       uint64_t Start = Symbols[SymIdx].Value - Sections[SectIdx].Address;
 294       uint64_t End = (SymIdx+1 == Symbols.size() ||
 295           Symbols[SymIdx].SectionIndex != Symbols[SymIdx+1].SectionIndex) ?
 296           Sections[SectIdx].Size :
 297           Symbols[SymIdx+1].Value - Sections[SectIdx].Address;
 298       uint64_t Size;
 299
 300       if (Start >= End)
 301         continue;
 302
 303       symbolTableWorked = true;
 304
 305       if (!CFG) {
 306         outs() << MachOObj->getStringAtIndex(Symbols[SymIdx].StringIndex)
 307           << ":\n";
 308         for (uint64_t Index = Start; Index < End; Index += Size) {
 309           MCInst Inst;
 310
 311           if (DisAsm->getInstruction(Inst, Size, memoryObject, Index,
 312                                      DebugOut, nulls())) {
 313             outs() << format("%8llx:\t", Sections[SectIdx].Address + Index);
 314             DumpBytes(StringRef(Bytes.data() + Index, Size));
 315             IP->printInst(&Inst, outs(), "");
 316             outs() << "\n";
 317           } else {
 318             errs() << "llvm-objdump: warning: invalid instruction encoding\n";
 319             if (Size == 0)
 320               Size = 1; // skip illegible bytes
 321           }
 322         }
 323       } else {
 324         // Create CFG and use it for disassembly.
 325         SmallVector<uint64_t, 16> Calls;
 326         MCFunction f =
 327           MCFunction::createFunctionFromMC(
 328               MachOObj->getStringAtIndex(Symbols[SymIdx].StringIndex),
 329               DisAsm.get(),
 330               memoryObject, Start, End,
 331               InstrAnalysis.get(), DebugOut,
 332               Calls);
 333
 334         Functions.push_back(f);
 335         FunctionMap[Start] = &Functions.back();
 336
 337         for (unsigned i = 0, e = Calls.size(); i != e; ++i)
 338           FunctionMap.insert(std::make_pair(Calls[i], (MCFunction*)0));
 339       }
 340     }
 341
 342     if (CFG) {
 343       if (!symbolTableWorked) {
 344         // Create CFG and use it for disassembly.
 345         SmallVector<uint64_t, 16> Calls;
 346         MCFunction f =
 347           MCFunction::createFunctionFromMC("__TEXT", DisAsm.get(),
 348               memoryObject, 0, Sections[SectIdx].Size,
 349               InstrAnalysis.get(), DebugOut,
 350               Calls);
 351
 352         Functions.push_back(f);
 353         FunctionMap[Sections[SectIdx].Offset] = &Functions.back();
 354
 355         for (unsigned i = 0, e = Calls.size(); i != e; ++i)
 356           FunctionMap.insert(std::make_pair(Calls[i], (MCFunction*)0));
 357       }
 358       for (std::map<uint64_t, MCFunction*>::iterator mi = FunctionMap.begin(),
 359            me = FunctionMap.end(); mi != me; ++mi)
 360         if (mi->second == 0) {
 361           SmallVector<uint64_t, 16> Calls;
 362           MCFunction f =
 363             MCFunction::createFunctionFromMC("unknown", DisAsm.get(),
 364                                              memoryObject, mi->first,
 365                                              Sections[SectIdx].Size,
 366                                              InstrAnalysis.get(), DebugOut,
 367                                              Calls);
 368           Functions.push_back(f);
 369           mi->second = &Functions.back();
 370           for (unsigned i = 0, e = Calls.size(); i != e; ++i)
 371             if (FunctionMap.insert(std::make_pair(Calls[i], (MCFunction*)0))
 372                                                                         .second)
 373               mi = FunctionMap.begin();
 374         }
 375
 376       DenseSet<uint64_t> PrintedBlocks;
 377       for (unsigned ffi = 0, ffe = Functions.size(); ffi != ffe; ++ffi) {
 378         MCFunction &f = Functions[ffi];
 379         for (MCFunction::iterator fi = f.begin(), fe = f.end(); fi != fe; ++fi){
 380           if (!PrintedBlocks.insert(fi->first).second)
 381             continue;
 382           bool hasPreds = FunctionMap.find(fi->first) != FunctionMap.end();
 383
 384           // Only print blocks that have predecessors.
 385           // FIXME: Slow.
 386           for (MCFunction::iterator pi = f.begin(), pe = f.end(); pi != pe;
 387               ++pi)
 388             if (pi->second.contains(fi->first)) {
 389               hasPreds = true;
 390               break;
 391             }
 392
 393           // Data block.
 394           if (!hasPreds && fi != f.begin()) {
 395             uint64_t End = llvm::next(fi) == fe ? Sections[SectIdx].Size :
 396                                                   llvm::next(fi)->first;
 397             outs() << "# " << End-fi->first << " bytes of data:\n";
 398             for (unsigned pos = fi->first; pos != End; ++pos) {
 399               outs() << format("%8x:\t", Sections[SectIdx].Address + pos);
 400               DumpBytes(StringRef(Bytes.data() + pos, 1));
 401               outs() << format("\t.byte 0x%02x\n", (uint8_t)Bytes[pos]);
 402             }
 403             continue;
 404           }
 405
 406           if (fi->second.contains(fi->first))
 407             outs() << "# Loop begin:\n";
 408
 409           for (unsigned ii = 0, ie = fi->second.getInsts().size(); ii != ie;
 410                ++ii) {
 411             const MCDecodedInst &Inst = fi->second.getInsts()[ii];
 412             if (FunctionMap.find(Sections[SectIdx].Address + Inst.Address) !=
 413                 FunctionMap.end())
 414               outs() << FunctionMap[Sections[SectIdx].Address + Inst.Address]->
 415                                                              getName() << ":\n";
 416             outs() << format("%8llx:\t", Sections[SectIdx].Address +
 417                                          Inst.Address);
 418             DumpBytes(StringRef(Bytes.data() + Inst.Address, Inst.Size));
 419             // Simple loops.
 420             if (fi->second.contains(fi->first))
 421               outs() << '\t';
 422             IP->printInst(&Inst.Inst, outs(), "");
 423             for (unsigned j = 0; j != Relocs.size(); ++j)
 424               if (Relocs[j].first >= Sections[SectIdx].Address + Inst.Address &&
 425                   Relocs[j].first < Sections[SectIdx].Address + Inst.Address +
 426                                     Inst.Size) {
 427                 outs() << "\t# "
 428                    << MachOObj->getStringAtIndex(
 429                                   UnsortedSymbols[Relocs[j].second].StringIndex)
 430                    << ' ';
 431                 DumpAddress(UnsortedSymbols[Relocs[j].second].Value, Sections,
 432                             MachOObj.get(), outs());
 433               }
 434             uint64_t targ = InstrAnalysis->evaluateBranch(Inst.Inst,
 435                                                           Inst.Address,
 436                                                           Inst.Size);
 437             if (targ != -1ULL)
 438               DumpAddress(targ, Sections, MachOObj.get(), outs());
 439
 440             outs() << '\n';
 441           }
 442         }
 443
 444         // Start a new dot file.
 445         std::string Error;
 446         raw_fd_ostream Out((f.getName().str() + ".dot").c_str(), Error);
 447         if (!Error.empty()) {
 448           errs() << "llvm-objdump: warning: " << Error << '\n';
 449           continue;
 450         }
 451
 452         Out << "digraph " << f.getName() << " {\n";
 453         Out << "graph [ rankdir = \"LR\" ];\n";
 454         for (MCFunction::iterator i = f.begin(), e = f.end(); i != e; ++i) {
 455           bool hasPreds = false;
 456           // Only print blocks that have predecessors.
 457           // FIXME: Slow.
 458           for (MCFunction::iterator pi = f.begin(), pe = f.end(); pi != pe;
 459                ++pi)
 460             if (pi->second.contains(i->first)) {
 461               hasPreds = true;
 462               break;
 463             }
 464
 465           if (!hasPreds && i != f.begin())
 466             continue;
 467
 468           Out << '"' << i->first << "\" [ label=\"<a>";
 469           // Print instructions.
 470           for (unsigned ii = 0, ie = i->second.getInsts().size(); ii != ie;
 471                ++ii) {
 472             // Escape special chars and print the instruction in mnemonic form.
 473             std::string Str;
 474             raw_string_ostream OS(Str);
 475             IP->printInst(&i->second.getInsts()[ii].Inst, OS, "");
 476             Out << DOT::EscapeString(OS.str()) << '|';
 477           }
 478           Out << "<o>\" shape=\"record\" ];\n";
 479
 480           // Add edges.
 481           for (MCBasicBlock::succ_iterator si = i->second.succ_begin(),
 482               se = i->second.succ_end(); si != se; ++si)
 483             Out << i->first << ":o -> " << *si <<":a\n";
 484         }
 485         Out << "}\n";
 486       }
 487     }
 488   }
 489 }