1 //===-- llvm-objdump.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 program is a utility that works like binutils "objdump", that is, it
11 // dumps out a plethora of information about an object file depending on the
12 // flags.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "llvm-objdump.h"
17 #include "MCFunction.h"
18 #include "llvm/Object/Archive.h"
19 #include "llvm/Object/COFF.h"
20 #include "llvm/Object/ObjectFile.h"
21 #include "llvm/ADT/OwningPtr.h"
22 #include "llvm/ADT/StringExtras.h"
23 #include "llvm/ADT/Triple.h"
24 #include "llvm/ADT/STLExtras.h"
25 #include "llvm/MC/MCAsmInfo.h"
26 #include "llvm/MC/MCDisassembler.h"
27 #include "llvm/MC/MCInst.h"
28 #include "llvm/MC/MCInstPrinter.h"
29 #include "llvm/MC/MCInstrInfo.h"
30 #include "llvm/MC/MCRegisterInfo.h"
31 #include "llvm/MC/MCSubtargetInfo.h"
32 #include "llvm/Support/Casting.h"
33 #include "llvm/Support/CommandLine.h"
34 #include "llvm/Support/Debug.h"
35 #include "llvm/Support/FileSystem.h"
36 #include "llvm/Support/Format.h"
37 #include "llvm/Support/GraphWriter.h"
38 #include "llvm/Support/Host.h"
39 #include "llvm/Support/ManagedStatic.h"
40 #include "llvm/Support/MemoryBuffer.h"
41 #include "llvm/Support/MemoryObject.h"
42 #include "llvm/Support/PrettyStackTrace.h"
43 #include "llvm/Support/Signals.h"
44 #include "llvm/Support/SourceMgr.h"
45 #include "llvm/Support/TargetRegistry.h"
46 #include "llvm/Support/TargetSelect.h"
47 #include "llvm/Support/raw_ostream.h"
48 #include "llvm/Support/system_error.h"
49 #include <algorithm>
50 #include <cctype>
51 #include <cstring>
52 using namespace llvm;
53 using namespace object;
54 
55 static cl::list<std::string>
56 InputFilenames(cl::Positional, cl::desc("<input object files>"),cl::ZeroOrMore);
57 
58 static cl::opt<bool>
59 Disassemble("disassemble",
60   cl::desc("Display assembler mnemonics for the machine instructions"));
61 static cl::alias
62 Disassembled("d", cl::desc("Alias for --disassemble"),
63              cl::aliasopt(Disassemble));
64 
65 static cl::opt<bool>
66 Relocations("r", cl::desc("Display the relocation entries in the file"));
67 
68 static cl::opt<bool>
69 SectionContents("s", cl::desc("Display the content of each section"));
70 
71 static cl::opt<bool>
72 SymbolTable("t", cl::desc("Display the symbol table"));
73 
74 static cl::opt<bool>
75 MachO("macho", cl::desc("Use MachO specific object file parser"));
76 static cl::alias
77 MachOm("m", cl::desc("Alias for --macho"), cl::aliasopt(MachO));
78 
79 cl::opt<std::string>
80 llvm::TripleName("triple", cl::desc("Target triple to disassemble for, "
81                                     "see -version for available targets"));
82 
83 cl::opt<std::string>
84 llvm::ArchName("arch", cl::desc("Target arch to disassemble for, "
85                                 "see -version for available targets"));
86 
87 static cl::opt<bool>
88 SectionHeaders("section-headers", cl::desc("Display summaries of the headers "
89                                            "for each section."));
90 static cl::alias
91 SectionHeadersShort("headers", cl::desc("Alias for --section-headers"),
92                     cl::aliasopt(SectionHeaders));
93 static cl::alias
94 SectionHeadersShorter("h", cl::desc("Alias for --section-headers"),
95                       cl::aliasopt(SectionHeaders));
96 
97 static cl::list<std::string>
98 MAttrs("mattr",
99   cl::CommaSeparated,
100   cl::desc("Target specific attributes"),
101   cl::value_desc("a1,+a2,-a3,..."));
102 
103 static cl::opt<bool>
104 NoShowRawInsn("no-show-raw-insn", cl::desc("When disassembling instructions, "
105                                            "do not print the instruction bytes."));
106 
107 static StringRef ToolName;
108 
109 static bool error(error_code ec) {
110   if (!ec) return false;
111 
112   outs() << ToolName << ": error reading file: " << ec.message() << ".\n";
113   outs().flush();
114   return true;
115 }
116 
117 static const Target *getTarget(const ObjectFile *Obj = NULL) {
118   // Figure out the target triple.
119   llvm::Triple TheTriple("unknown-unknown-unknown");
120   if (TripleName.empty()) {
121     if (Obj)
122       TheTriple.setArch(Triple::ArchType(Obj->getArch()));
123   } else
124     TheTriple.setTriple(Triple::normalize(TripleName));
125 
126   // Get the target specific parser.
127   std::string Error;
128   const Target *TheTarget = TargetRegistry::lookupTarget(ArchName, TheTriple,
129                                                          Error);
130   if (!TheTarget) {
131     errs() << ToolName << ": " << Error;
132     return 0;
133   }
134 
135   // Update the triple name and return the found target.
136   TripleName = TheTriple.getTriple();
137   return TheTarget;
138 }
139 
140 void llvm::StringRefMemoryObject::anchor() { }
141 
142 void llvm::DumpBytes(StringRef bytes) {
143   static const char hex_rep[] = "0123456789abcdef";
144   // FIXME: The real way to do this is to figure out the longest instruction
145   //        and align to that size before printing. I'll fix this when I get
146   //        around to outputting relocations.
147   // 15 is the longest x86 instruction
148   // 3 is for the hex rep of a byte + a space.
149   // 1 is for the null terminator.
150   enum { OutputSize = (15 * 3) + 1 };
151   char output[OutputSize];
152 
153   assert(bytes.size() <= 15
154     && "DumpBytes only supports instructions of up to 15 bytes");
155   memset(output, ' ', sizeof(output));
156   unsigned index = 0;
157   for (StringRef::iterator i = bytes.begin(),
158                            e = bytes.end(); i != e; ++i) {
159     output[index] = hex_rep[(*i & 0xF0) >> 4];
160     output[index + 1] = hex_rep[*i & 0xF];
161     index += 3;
162   }
163 
164   output[sizeof(output) - 1] = 0;
165   outs() << output;
166 }
167 
168 static bool RelocAddressLess(RelocationRef a, RelocationRef b) {
169   uint64_t a_addr, b_addr;
170   if (error(a.getAddress(a_addr))) return false;
171   if (error(b.getAddress(b_addr))) return false;
172   return a_addr < b_addr;
173 }
174 
175 static void DisassembleObject(const ObjectFile *Obj, bool InlineRelocs) {
176   const Target *TheTarget = getTarget(Obj);
177   // getTarget() will have already issued a diagnostic if necessary, so
178   // just bail here if it failed.
179   if (!TheTarget)
180     return;
181 
182   // Package up features to be passed to target/subtarget
183   std::string FeaturesStr;
184   if (MAttrs.size()) {
185     SubtargetFeatures Features;
186     for (unsigned i = 0; i != MAttrs.size(); ++i)
187       Features.AddFeature(MAttrs[i]);
188     FeaturesStr = Features.getString();
189   }
190 
191   error_code ec;
192   for (section_iterator i = Obj->begin_sections(),
193                         e = Obj->end_sections();
194                         i != e; i.increment(ec)) {
195     if (error(ec)) break;
196     bool text;
197     if (error(i->isText(text))) break;
198     if (!text) continue;
199 
200     uint64_t SectionAddr;
201     if (error(i->getAddress(SectionAddr))) break;
202 
203     // Make a list of all the symbols in this section.
204     std::vector<std::pair<uint64_t, StringRef> > Symbols;
205     for (symbol_iterator si = Obj->begin_symbols(),
206                          se = Obj->end_symbols();
207                          si != se; si.increment(ec)) {
208       bool contains;
209       if (!error(i->containsSymbol(*si, contains)) && contains) {
210         uint64_t Address;
211         if (error(si->getAddress(Address))) break;
212         Address -= SectionAddr;
213 
214         StringRef Name;
215         if (error(si->getName(Name))) break;
216         Symbols.push_back(std::make_pair(Address, Name));
217       }
218     }
219 
220     // Sort the symbols by address, just in case they didn't come in that way.
221     array_pod_sort(Symbols.begin(), Symbols.end());
222 
223     // Make a list of all the relocations for this section.
224     std::vector<RelocationRef> Rels;
225     if (InlineRelocs) {
226       for (relocation_iterator ri = i->begin_relocations(),
227                                re = i->end_relocations();
228                                ri != re; ri.increment(ec)) {
229         if (error(ec)) break;
230         Rels.push_back(*ri);
231       }
232     }
233 
234     // Sort relocations by address.
235     std::sort(Rels.begin(), Rels.end(), RelocAddressLess);
236 
237     StringRef name;
238     if (error(i->getName(name))) break;
239     outs() << "Disassembly of section " << name << ':';
240 
241     // If the section has no symbols just insert a dummy one and disassemble
242     // the whole section.
243     if (Symbols.empty())
244       Symbols.push_back(std::make_pair(0, name));
245 
246     // Set up disassembler.
247     OwningPtr<const MCAsmInfo> AsmInfo(TheTarget->createMCAsmInfo(TripleName));
248 
249     if (!AsmInfo) {
250       errs() << "error: no assembly info for target " << TripleName << "\n";
251       return;
252     }
253 
254     OwningPtr<const MCSubtargetInfo> STI(
255       TheTarget->createMCSubtargetInfo(TripleName, "", FeaturesStr));
256 
257     if (!STI) {
258       errs() << "error: no subtarget info for target " << TripleName << "\n";
259       return;
260     }
261 
262     OwningPtr<const MCDisassembler> DisAsm(
263       TheTarget->createMCDisassembler(*STI));
264     if (!DisAsm) {
265       errs() << "error: no disassembler for target " << TripleName << "\n";
266       return;
267     }
268 
269     OwningPtr<const MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
270     if (!MRI) {
271       errs() << "error: no register info for target " << TripleName << "\n";
272       return;
273     }
274 
275     OwningPtr<const MCInstrInfo> MII(TheTarget->createMCInstrInfo());
276     if (!MII) {
277       errs() << "error: no instruction info for target " << TripleName << "\n";
278       return;
279     }
280 
281     int AsmPrinterVariant = AsmInfo->getAssemblerDialect();
282     OwningPtr<MCInstPrinter> IP(TheTarget->createMCInstPrinter(
283                                 AsmPrinterVariant, *AsmInfo, *MII, *MRI, *STI));
284     if (!IP) {
285       errs() << "error: no instruction printer for target " << TripleName
286              << '\n';
287       return;
288     }
289 
290     StringRef Bytes;
291     if (error(i->getContents(Bytes))) break;
292     StringRefMemoryObject memoryObject(Bytes);
293     uint64_t Size;
294     uint64_t Index;
295     uint64_t SectSize;
296     if (error(i->getSize(SectSize))) break;
297 
298     std::vector<RelocationRef>::const_iterator rel_cur = Rels.begin();
299     std::vector<RelocationRef>::const_iterator rel_end = Rels.end();
300     // Disassemble symbol by symbol.
301     for (unsigned si = 0, se = Symbols.size(); si != se; ++si) {
302       uint64_t Start = Symbols[si].first;
303       uint64_t End;
304       // The end is either the size of the section or the beginning of the next
305       // symbol.
306       if (si == se - 1)
307         End = SectSize;
308       // Make sure this symbol takes up space.
309       else if (Symbols[si + 1].first != Start)
310         End = Symbols[si + 1].first - 1;
311       else
312         // This symbol has the same address as the next symbol. Skip it.
313         continue;
314 
315       outs() << '\n' << Symbols[si].second << ":\n";
316 
317 #ifndef NDEBUG
318         raw_ostream &DebugOut = DebugFlag ? dbgs() : nulls();
319 #else
320         raw_ostream &DebugOut = nulls();
321 #endif
322 
323       for (Index = Start; Index < End; Index += Size) {
324         MCInst Inst;
325 
326         if (DisAsm->getInstruction(Inst, Size, memoryObject, Index,
327                                    DebugOut, nulls())) {
328           outs() << format("%8" PRIx64 ":", SectionAddr + Index);
329           if (!NoShowRawInsn) {
330             outs() << "\t";
331             DumpBytes(StringRef(Bytes.data() + Index, Size));
332           }
333           IP->printInst(&Inst, outs(), "");
334           outs() << "\n";
335         } else {
336           errs() << ToolName << ": warning: invalid instruction encoding\n";
337           if (Size == 0)
338             Size = 1; // skip illegible bytes
339         }
340 
341         // Print relocation for instruction.
342         while (rel_cur != rel_end) {
343           bool hidden = false;
344           uint64_t addr;
345           SmallString<16> name;
346           SmallString<32> val;
347 
348           // If this relocation is hidden, skip it.
349           if (error(rel_cur->getHidden(hidden))) goto skip_print_rel;
350           if (hidden) goto skip_print_rel;
351 
352           if (error(rel_cur->getAddress(addr))) goto skip_print_rel;
353           // Stop when rel_cur's address is past the current instruction.
354           if (addr >= Index + Size) break;
355           if (error(rel_cur->getTypeName(name))) goto skip_print_rel;
356           if (error(rel_cur->getValueString(val))) goto skip_print_rel;
357 
358           outs() << format("\t\t\t%8" PRIx64 ": ", SectionAddr + addr) << name
359                  << "\t" << val << "\n";
360 
361         skip_print_rel:
362           ++rel_cur;
363         }
364       }
365     }
366   }
367 }
368 
369 static void PrintRelocations(const ObjectFile *o) {
370   error_code ec;
371   for (section_iterator si = o->begin_sections(), se = o->end_sections();
372                                                   si != se; si.increment(ec)){
373     if (error(ec)) return;
374     if (si->begin_relocations() == si->end_relocations())
375       continue;
376     StringRef secname;
377     if (error(si->getName(secname))) continue;
378     outs() << "RELOCATION RECORDS FOR [" << secname << "]:\n";
379     for (relocation_iterator ri = si->begin_relocations(),
380                              re = si->end_relocations();
381                              ri != re; ri.increment(ec)) {
382       if (error(ec)) return;
383 
384       bool hidden;
385       uint64_t address;
386       SmallString<32> relocname;
387       SmallString<32> valuestr;
388       if (error(ri->getHidden(hidden))) continue;
389       if (hidden) continue;
390       if (error(ri->getTypeName(relocname))) continue;
391       if (error(ri->getAddress(address))) continue;
392       if (error(ri->getValueString(valuestr))) continue;
393       outs() << address << " " << relocname << " " << valuestr << "\n";
394     }
395     outs() << "\n";
396   }
397 }
398 
399 static void PrintSectionHeaders(const ObjectFile *o) {
400   outs() << "Sections:\n"
401             "Idx Name          Size      Address          Type\n";
402   error_code ec;
403   unsigned i = 0;
404   for (section_iterator si = o->begin_sections(), se = o->end_sections();
405                                                   si != se; si.increment(ec)) {
406     if (error(ec)) return;
407     StringRef Name;
408     if (error(si->getName(Name))) return;
409     uint64_t Address;
410     if (error(si->getAddress(Address))) return;
411     uint64_t Size;
412     if (error(si->getSize(Size))) return;
413     bool Text, Data, BSS;
414     if (error(si->isText(Text))) return;
415     if (error(si->isData(Data))) return;
416     if (error(si->isBSS(BSS))) return;
417     std::string Type = (std::string(Text ? "TEXT " : "") +
418                         (Data ? "DATA " : "") + (BSS ? "BSS" : ""));
419     outs() << format("%3d %-13s %09" PRIx64 " %017" PRIx64 " %s\n",
420                      i, Name.str().c_str(), Size, Address, Type.c_str());
421     ++i;
422   }
423 }
424 
425 static void PrintSectionContents(const ObjectFile *o) {
426   error_code ec;
427   for (section_iterator si = o->begin_sections(),
428                         se = o->end_sections();
429                         si != se; si.increment(ec)) {
430     if (error(ec)) return;
431     StringRef Name;
432     StringRef Contents;
433     uint64_t BaseAddr;
434     if (error(si->getName(Name))) continue;
435     if (error(si->getContents(Contents))) continue;
436     if (error(si->getAddress(BaseAddr))) continue;
437 
438     outs() << "Contents of section " << Name << ":\n";
439 
440     // Dump out the content as hex and printable ascii characters.
441     for (std::size_t addr = 0, end = Contents.size(); addr < end; addr += 16) {
442       outs() << format(" %04" PRIx64 " ", BaseAddr + addr);
443       // Dump line of hex.
444       for (std::size_t i = 0; i < 16; ++i) {
445         if (i != 0 && i % 4 == 0)
446           outs() << ' ';
447         if (addr + i < end)
448           outs() << hexdigit((Contents[addr + i] >> 4) & 0xF, true)
449                  << hexdigit(Contents[addr + i] & 0xF, true);
450         else
451           outs() << "  ";
452       }
453       // Print ascii.
454       outs() << "  ";
455       for (std::size_t i = 0; i < 16 && addr + i < end; ++i) {
456         if (std::isprint(Contents[addr + i] & 0xFF))
457           outs() << Contents[addr + i];
458         else
459           outs() << ".";
460       }
461       outs() << "\n";
462     }
463   }
464 }
465 
466 static void PrintCOFFSymbolTable(const COFFObjectFile *coff) {
467   const coff_file_header *header;
468   if (error(coff->getHeader(header))) return;
469   int aux_count = 0;
470   const coff_symbol *symbol = 0;
471   for (int i = 0, e = header->NumberOfSymbols; i != e; ++i) {
472     if (aux_count--) {
473       // Figure out which type of aux this is.
474       if (symbol->StorageClass == COFF::IMAGE_SYM_CLASS_STATIC
475           && symbol->Value == 0) { // Section definition.
476         const coff_aux_section_definition *asd;
477         if (error(coff->getAuxSymbol<coff_aux_section_definition>(i, asd)))
478           return;
479         outs() << "AUX "
480                << format("scnlen 0x%x nreloc %d nlnno %d checksum 0x%x "
481                          , unsigned(asd->Length)
482                          , unsigned(asd->NumberOfRelocations)
483                          , unsigned(asd->NumberOfLinenumbers)
484                          , unsigned(asd->CheckSum))
485                << format("assoc %d comdat %d\n"
486                          , unsigned(asd->Number)
487                          , unsigned(asd->Selection));
488       } else
489         outs() << "AUX Unknown\n";
490     } else {
491       StringRef name;
492       if (error(coff->getSymbol(i, symbol))) return;
493       if (error(coff->getSymbolName(symbol, name))) return;
494       outs() << "[" << format("%2d", i) << "]"
495              << "(sec " << format("%2d", int(symbol->SectionNumber)) << ")"
496              << "(fl 0x00)" // Flag bits, which COFF doesn't have.
497              << "(ty " << format("%3x", unsigned(symbol->Type)) << ")"
498              << "(scl " << format("%3x", unsigned(symbol->StorageClass)) << ") "
499              << "(nx " << unsigned(symbol->NumberOfAuxSymbols) << ") "
500              << "0x" << format("%08x", unsigned(symbol->Value)) << " "
501              << name << "\n";
502       aux_count = symbol->NumberOfAuxSymbols;
503     }
504   }
505 }
506 
507 static void PrintSymbolTable(const ObjectFile *o) {
508   outs() << "SYMBOL TABLE:\n";
509 
510   if (const COFFObjectFile *coff = dyn_cast<const COFFObjectFile>(o))
511     PrintCOFFSymbolTable(coff);
512   else {
513     error_code ec;
514     for (symbol_iterator si = o->begin_symbols(),
515                          se = o->end_symbols(); si != se; si.increment(ec)) {
516       if (error(ec)) return;
517       StringRef Name;
518       uint64_t Address;
519       SymbolRef::Type Type;
520       uint64_t Size;
521       uint32_t Flags;
522       section_iterator Section = o->end_sections();
523       if (error(si->getName(Name))) continue;
524       if (error(si->getAddress(Address))) continue;
525       if (error(si->getFlags(Flags))) continue;
526       if (error(si->getType(Type))) continue;
527       if (error(si->getSize(Size))) continue;
528       if (error(si->getSection(Section))) continue;
529 
530       bool Global = Flags & SymbolRef::SF_Global;
531       bool Weak = Flags & SymbolRef::SF_Weak;
532       bool Absolute = Flags & SymbolRef::SF_Absolute;
533 
534       if (Address == UnknownAddressOrSize)
535         Address = 0;
536       if (Size == UnknownAddressOrSize)
537         Size = 0;
538       char GlobLoc = ' ';
539       if (Type != SymbolRef::ST_Unknown)
540         GlobLoc = Global ? 'g' : 'l';
541       char Debug = (Type == SymbolRef::ST_Debug || Type == SymbolRef::ST_File)
542                    ? 'd' : ' ';
543       char FileFunc = ' ';
544       if (Type == SymbolRef::ST_File)
545         FileFunc = 'f';
546       else if (Type == SymbolRef::ST_Function)
547         FileFunc = 'F';
548 
549       outs() << format("%08" PRIx64, Address) << " "
550              << GlobLoc // Local -> 'l', Global -> 'g', Neither -> ' '
551              << (Weak ? 'w' : ' ') // Weak?
552              << ' ' // Constructor. Not supported yet.
553              << ' ' // Warning. Not supported yet.
554              << ' ' // Indirect reference to another symbol.
555              << Debug // Debugging (d) or dynamic (D) symbol.
556              << FileFunc // Name of function (F), file (f) or object (O).
557              << ' ';
558       if (Absolute)
559         outs() << "*ABS*";
560       else if (Section == o->end_sections())
561         outs() << "*UND*";
562       else {
563         StringRef SectionName;
564         if (error(Section->getName(SectionName)))
565           SectionName = "";
566         outs() << SectionName;
567       }
568       outs() << '\t'
569              << format("%08" PRIx64 " ", Size)
570              << Name
571              << '\n';
572     }
573   }
574 }
575 
576 static void DumpObject(const ObjectFile *o) {
577   outs() << '\n';
578   outs() << o->getFileName()
579          << ":\tfile format " << o->getFileFormatName() << "\n\n";
580 
581   if (Disassemble)
582     DisassembleObject(o, Relocations);
583   if (Relocations && !Disassemble)
584     PrintRelocations(o);
585   if (SectionHeaders)
586     PrintSectionHeaders(o);
587   if (SectionContents)
588     PrintSectionContents(o);
589   if (SymbolTable)
590     PrintSymbolTable(o);
591 }
592 
593 /// @brief Dump each object file in \a a;
594 static void DumpArchive(const Archive *a) {
595   for (Archive::child_iterator i = a->begin_children(),
596                                e = a->end_children(); i != e; ++i) {
597     OwningPtr<Binary> child;
598     if (error_code ec = i->getAsBinary(child)) {
599       // Ignore non-object files.
600       if (ec != object_error::invalid_file_type)
601         errs() << ToolName << ": '" << a->getFileName() << "': " << ec.message()
602                << ".\n";
603       continue;
604     }
605     if (ObjectFile *o = dyn_cast<ObjectFile>(child.get()))
606       DumpObject(o);
607     else
608       errs() << ToolName << ": '" << a->getFileName() << "': "
609               << "Unrecognized file type.\n";
610   }
611 }
612 
613 /// @brief Open file and figure out how to dump it.
614 static void DumpInput(StringRef file) {
615   // If file isn't stdin, check that it exists.
616   if (file != "-" && !sys::fs::exists(file)) {
617     errs() << ToolName << ": '" << file << "': " << "No such file\n";
618     return;
619   }
620 
621   if (MachO && Disassemble) {
622     DisassembleInputMachO(file);
623     return;
624   }
625 
626   // Attempt to open the binary.
627   OwningPtr<Binary> binary;
628   if (error_code ec = createBinary(file, binary)) {
629     errs() << ToolName << ": '" << file << "': " << ec.message() << ".\n";
630     return;
631   }
632 
633   if (Archive *a = dyn_cast<Archive>(binary.get()))
634     DumpArchive(a);
635   else if (ObjectFile *o = dyn_cast<ObjectFile>(binary.get()))
636     DumpObject(o);
637   else
638     errs() << ToolName << ": '" << file << "': " << "Unrecognized file type.\n";
639 }
640 
641 int main(int argc, char **argv) {
642   // Print a stack trace if we signal out.
643   sys::PrintStackTraceOnErrorSignal();
644   PrettyStackTraceProgram X(argc, argv);
645   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
646 
647   // Initialize targets and assembly printers/parsers.
648   llvm::InitializeAllTargetInfos();
649   llvm::InitializeAllTargetMCs();
650   llvm::InitializeAllAsmParsers();
651   llvm::InitializeAllDisassemblers();
652 
653   // Register the target printer for --version.
654   cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
655 
656   cl::ParseCommandLineOptions(argc, argv, "llvm object file dumper\n");
657   TripleName = Triple::normalize(TripleName);
658 
659   ToolName = argv[0];
660 
661   // Defaults to a.out if no filenames specified.
662   if (InputFilenames.size() == 0)
663     InputFilenames.push_back("a.out");
664 
665   if (!Disassemble
666       && !Relocations
667       && !SectionHeaders
668       && !SectionContents
669       && !SymbolTable) {
670     cl::PrintHelpMessage();
671     return 2;
672   }
673 
674   std::for_each(InputFilenames.begin(), InputFilenames.end(),
675                 DumpInput);
676 
677   return 0;
678 }
679