MachODump.cpp revision 6c1202c459ffa6d693ad92fa84e43902bc780bca 
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/OwningPtr.h"
16#include "llvm/ADT/STLExtras.h"
17#include "llvm/ADT/StringExtras.h"
18#include "llvm/ADT/Triple.h"
19#include "llvm/DebugInfo/DIContext.h"
20#include "llvm/MC/MCAsmInfo.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 "llvm/Support/system_error.h"
41#include <algorithm>
42#include <cstring>
43using namespace llvm;
44using namespace object;
45
46static cl::opt<bool>
47  UseDbg("g", cl::desc("Print line information from debug info if available"));
48
49static cl::opt<std::string>
50  DSYMFile("dsym", cl::desc("Use .dSYM file for debug info"));
51
52static 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 0;
69}
70
71struct 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
90static void
91getSectionsAndSymbols(const macho::Header Header,
92                      MachOObjectFile *MachOObj,
93                      std::vector<SectionRef> &Sections,
94                      std::vector<SymbolRef> &Symbols,
95                      SmallVectorImpl<uint64_t> &FoundFns) {
96  error_code ec;
97  for (symbol_iterator SI = MachOObj->begin_symbols(),
98       SE = MachOObj->end_symbols(); SI != SE; SI.increment(ec))
99    Symbols.push_back(*SI);
100
101  for (section_iterator SI = MachOObj->begin_sections(),
102       SE = MachOObj->end_sections(); SI != SE; SI.increment(ec)) {
103    SectionRef SR = *SI;
104    StringRef SectName;
105    SR.getName(SectName);
106    Sections.push_back(*SI);
107  }
108
109  MachOObjectFile::LoadCommandInfo Command =
110    MachOObj->getFirstLoadCommandInfo();
111  for (unsigned i = 0; ; ++i) {
112    if (Command.C.Type == macho::LCT_FunctionStarts) {
113      // We found a function starts segment, parse the addresses for later
114      // consumption.
115      macho::LinkeditDataLoadCommand LLC =
116        MachOObj->getLinkeditDataLoadCommand(Command);
117
118      MachOObj->ReadULEB128s(LLC.DataOffset, FoundFns);
119    }
120
121    if (i == Header.NumLoadCommands - 1)
122      break;
123    else
124      Command = MachOObj->getNextLoadCommandInfo(Command);
125  }
126}
127
128static void DisassembleInputMachO2(StringRef Filename,
129                                   MachOObjectFile *MachOOF);
130
131void llvm::DisassembleInputMachO(StringRef Filename) {
132  OwningPtr<MemoryBuffer> Buff;
133
134  if (error_code ec = MemoryBuffer::getFileOrSTDIN(Filename, Buff)) {
135    errs() << "llvm-objdump: " << Filename << ": " << ec.message() << "\n";
136    return;
137  }
138
139  OwningPtr<MachOObjectFile> MachOOF(static_cast<MachOObjectFile*>(
140        ObjectFile::createMachOObjectFile(Buff.take())));
141
142  DisassembleInputMachO2(Filename, MachOOF.get());
143}
144
145static void DisassembleInputMachO2(StringRef Filename,
146                                   MachOObjectFile *MachOOF) {
147  const Target *TheTarget = GetTarget(MachOOF);
148  if (!TheTarget) {
149    // GetTarget prints out stuff.
150    return;
151  }
152  OwningPtr<const MCInstrInfo> InstrInfo(TheTarget->createMCInstrInfo());
153  OwningPtr<MCInstrAnalysis>
154    InstrAnalysis(TheTarget->createMCInstrAnalysis(InstrInfo.get()));
155
156  // Set up disassembler.
157  OwningPtr<const MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
158  OwningPtr<const MCAsmInfo> AsmInfo(
159      TheTarget->createMCAsmInfo(*MRI, TripleName));
160  OwningPtr<const MCSubtargetInfo>
161    STI(TheTarget->createMCSubtargetInfo(TripleName, "", ""));
162  OwningPtr<const MCDisassembler> DisAsm(TheTarget->createMCDisassembler(*STI));
163  int AsmPrinterVariant = AsmInfo->getAssemblerDialect();
164  OwningPtr<MCInstPrinter>
165    IP(TheTarget->createMCInstPrinter(AsmPrinterVariant, *AsmInfo, *InstrInfo,
166                                      *MRI, *STI));
167
168  if (!InstrAnalysis || !AsmInfo || !STI || !DisAsm || !IP) {
169    errs() << "error: couldn't initialize disassembler for target "
170           << TripleName << '\n';
171    return;
172  }
173
174  outs() << '\n' << Filename << ":\n\n";
175
176  macho::Header Header = MachOOF->getHeader();
177
178  // FIXME: FoundFns isn't used anymore. Using symbols/LC_FUNCTION_STARTS to
179  // determine function locations will eventually go in MCObjectDisassembler.
180  // FIXME: Using the -cfg command line option, this code used to be able to
181  // annotate relocations with the referenced symbol's name, and if this was
182  // inside a __[cf]string section, the data it points to. This is now replaced
183  // by the upcoming MCSymbolizer, which needs the appropriate setup done above.
184  std::vector<SectionRef> Sections;
185  std::vector<SymbolRef> Symbols;
186  SmallVector<uint64_t, 8> FoundFns;
187
188  getSectionsAndSymbols(Header, MachOOF, Sections, Symbols, FoundFns);
189
190  // Make a copy of the unsorted symbol list. FIXME: duplication
191  std::vector<SymbolRef> UnsortedSymbols(Symbols);
192  // Sort the symbols by address, just in case they didn't come in that way.
193  std::sort(Symbols.begin(), Symbols.end(), SymbolSorter());
194
195#ifndef NDEBUG
196  raw_ostream &DebugOut = DebugFlag ? dbgs() : nulls();
197#else
198  raw_ostream &DebugOut = nulls();
199#endif
200
201  OwningPtr<DIContext> diContext;
202  ObjectFile *DbgObj = MachOOF;
203  // Try to find debug info and set up the DIContext for it.
204  if (UseDbg) {
205    // A separate DSym file path was specified, parse it as a macho file,
206    // get the sections and supply it to the section name parsing machinery.
207    if (!DSYMFile.empty()) {
208      OwningPtr<MemoryBuffer> Buf;
209      if (error_code ec = MemoryBuffer::getFileOrSTDIN(DSYMFile.c_str(), Buf)) {
210        errs() << "llvm-objdump: " << Filename << ": " << ec.message() << '\n';
211        return;
212      }
213      DbgObj = ObjectFile::createMachOObjectFile(Buf.take());
214    }
215
216    // Setup the DIContext
217    diContext.reset(DIContext::getDWARFContext(DbgObj));
218  }
219
220  for (unsigned SectIdx = 0; SectIdx != Sections.size(); SectIdx++) {
221
222    bool SectIsText = false;
223    Sections[SectIdx].isText(SectIsText);
224    if (SectIsText == false)
225      continue;
226
227    StringRef SectName;
228    if (Sections[SectIdx].getName(SectName) ||
229        SectName != "__text")
230      continue; // Skip non-text sections
231
232    DataRefImpl DR = Sections[SectIdx].getRawDataRefImpl();
233
234    StringRef SegmentName = MachOOF->getSectionFinalSegmentName(DR);
235    if (SegmentName != "__TEXT")
236      continue;
237
238    StringRef Bytes;
239    Sections[SectIdx].getContents(Bytes);
240    StringRefMemoryObject memoryObject(Bytes);
241    bool symbolTableWorked = false;
242
243    // Parse relocations.
244    std::vector<std::pair<uint64_t, SymbolRef> > Relocs;
245    error_code ec;
246    for (relocation_iterator RI = Sections[SectIdx].begin_relocations(),
247         RE = Sections[SectIdx].end_relocations(); RI != RE; RI.increment(ec)) {
248      uint64_t RelocOffset, SectionAddress;
249      RI->getOffset(RelocOffset);
250      Sections[SectIdx].getAddress(SectionAddress);
251      RelocOffset -= SectionAddress;
252
253      symbol_iterator RelocSym = RI->getSymbol();
254
255      Relocs.push_back(std::make_pair(RelocOffset, *RelocSym));
256    }
257    array_pod_sort(Relocs.begin(), Relocs.end());
258
259    // Disassemble symbol by symbol.
260    for (unsigned SymIdx = 0; SymIdx != Symbols.size(); SymIdx++) {
261      StringRef SymName;
262      Symbols[SymIdx].getName(SymName);
263
264      SymbolRef::Type ST;
265      Symbols[SymIdx].getType(ST);
266      if (ST != SymbolRef::ST_Function)
267        continue;
268
269      // Make sure the symbol is defined in this section.
270      bool containsSym = false;
271      Sections[SectIdx].containsSymbol(Symbols[SymIdx], containsSym);
272      if (!containsSym)
273        continue;
274
275      // Start at the address of the symbol relative to the section's address.
276      uint64_t SectionAddress = 0;
277      uint64_t Start = 0;
278      Sections[SectIdx].getAddress(SectionAddress);
279      Symbols[SymIdx].getAddress(Start);
280      Start -= SectionAddress;
281
282      // Stop disassembling either at the beginning of the next symbol or at
283      // the end of the section.
284      bool containsNextSym = false;
285      uint64_t NextSym = 0;
286      uint64_t NextSymIdx = SymIdx+1;
287      while (Symbols.size() > NextSymIdx) {
288        SymbolRef::Type NextSymType;
289        Symbols[NextSymIdx].getType(NextSymType);
290        if (NextSymType == SymbolRef::ST_Function) {
291          Sections[SectIdx].containsSymbol(Symbols[NextSymIdx],
292                                           containsNextSym);
293          Symbols[NextSymIdx].getAddress(NextSym);
294          NextSym -= SectionAddress;
295          break;
296        }
297        ++NextSymIdx;
298      }
299
300      uint64_t SectSize;
301      Sections[SectIdx].getSize(SectSize);
302      uint64_t End = containsNextSym ?  NextSym : SectSize;
303      uint64_t Size;
304
305      symbolTableWorked = true;
306
307      outs() << SymName << ":\n";
308      DILineInfo lastLine;
309      for (uint64_t Index = Start; Index < End; Index += Size) {
310        MCInst Inst;
311
312        if (DisAsm->getInstruction(Inst, Size, memoryObject, Index,
313                                   DebugOut, nulls())) {
314          uint64_t SectAddress = 0;
315          Sections[SectIdx].getAddress(SectAddress);
316          outs() << format("%8" PRIx64 ":\t", SectAddress + Index);
317
318          DumpBytes(StringRef(Bytes.data() + Index, Size));
319          IP->printInst(&Inst, outs(), "");
320
321          // Print debug info.
322          if (diContext) {
323            DILineInfo dli =
324              diContext->getLineInfoForAddress(SectAddress + Index);
325            // Print valid line info if it changed.
326            if (dli != lastLine && dli.getLine() != 0)
327              outs() << "\t## " << dli.getFileName() << ':'
328                << dli.getLine() << ':' << dli.getColumn();
329            lastLine = dli;
330          }
331          outs() << "\n";
332        } else {
333          errs() << "llvm-objdump: warning: invalid instruction encoding\n";
334          if (Size == 0)
335            Size = 1; // skip illegible bytes
336        }
337      }
338    }
339    if (!symbolTableWorked) {
340      // Reading the symbol table didn't work, disassemble the whole section.
341      uint64_t SectAddress;
342      Sections[SectIdx].getAddress(SectAddress);
343      uint64_t SectSize;
344      Sections[SectIdx].getSize(SectSize);
345      uint64_t InstSize;
346      for (uint64_t Index = 0; Index < SectSize; Index += InstSize) {
347        MCInst Inst;
348
349        if (DisAsm->getInstruction(Inst, InstSize, memoryObject, Index,
350                                   DebugOut, nulls())) {
351          outs() << format("%8" PRIx64 ":\t", SectAddress + Index);
352          DumpBytes(StringRef(Bytes.data() + Index, InstSize));
353          IP->printInst(&Inst, outs(), "");
354          outs() << "\n";
355        } else {
356          errs() << "llvm-objdump: warning: invalid instruction encoding\n";
357          if (InstSize == 0)
358            InstSize = 1; // skip illegible bytes
359        }
360      }
361    }
362  }
363}
364