tools/llvm-objdump/llvm-objdump.cpp

   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/Object/ObjectFile.h"
  17 #include "llvm/ADT/OwningPtr.h"
  18 #include "llvm/ADT/Triple.h"
  19 #include "llvm/MC/MCAsmInfo.h"
  20 #include "llvm/MC/MCDisassembler.h"
  21 #include "llvm/MC/MCInst.h"
  22 #include "llvm/MC/MCInstPrinter.h"
  23 #include "llvm/Support/CommandLine.h"
  24 #include "llvm/Support/Debug.h"
  25 #include "llvm/Support/Format.h"
  26 #include "llvm/Support/Host.h"
  27 #include "llvm/Support/ManagedStatic.h"
  28 #include "llvm/Support/MemoryBuffer.h"
  29 #include "llvm/Support/MemoryObject.h"
  30 #include "llvm/Support/PrettyStackTrace.h"
  31 #include "llvm/Support/Signals.h"
  32 #include "llvm/Support/SourceMgr.h"
  33 #include "llvm/Support/raw_ostream.h"
  34 #include "llvm/Support/system_error.h"
  35 #include "llvm/Target/TargetRegistry.h"
  36 #include "llvm/Target/TargetSelect.h"
  37 #include <algorithm>
  38 #include <cstring>
  39 using namespace llvm;
  40 using namespace object;
  41
  42 namespace {
  43   cl::list<std::string>
  44   InputFilenames(cl::Positional, cl::desc("<input object files>"),
  45                  cl::ZeroOrMore);
  46
  47   cl::opt<bool>
  48   Disassemble("disassemble",
  49     cl::desc("Display assembler mnemonics for the machine instructions"));
  50   cl::alias
  51   Disassembled("d", cl::desc("Alias for --disassemble"),
  52                cl::aliasopt(Disassemble));
  53
  54   cl::opt<std::string>
  55   TripleName("triple", cl::desc("Target triple to disassemble for, "
  56                                 "see -version for available targets"));
  57
  58   cl::opt<std::string>
  59   ArchName("arch", cl::desc("Target arch to disassemble for, "
  60                             "see -version for available targets"));
  61
  62   StringRef ToolName;
  63
  64   bool error(error_code ec) {
  65     if (!ec) return false;
  66
  67     outs() << ToolName << ": error reading file: " << ec.message() << ".\n";
  68     outs().flush();
  69     return true;
  70   }
  71 }
  72
  73 static const Target *GetTarget(const ObjectFile *Obj = NULL) {
  74   // Figure out the target triple.
  75   llvm::Triple TT("unknown-unknown-unknown");
  76   if (TripleName.empty()) {
  77     if (Obj)
  78       TT.setArch(Triple::ArchType(Obj->getArch()));
  79   } else
  80     TT.setTriple(Triple::normalize(TripleName));
  81
  82   if (!ArchName.empty())
  83     TT.setArchName(ArchName);
  84
  85   TripleName = TT.str();
  86
  87   // Get the target specific parser.
  88   std::string Error;
  89   const Target *TheTarget = TargetRegistry::lookupTarget(TripleName, Error);
  90   if (TheTarget)
  91     return TheTarget;
  92
  93   errs() << ToolName << ": error: unable to get target for '" << TripleName
  94          << "', see --version and --triple.\n";
  95   return 0;
  96 }
  97
  98 namespace {
  99 class StringRefMemoryObject : public MemoryObject {
 100 private:
 101   StringRef Bytes;
 102 public:
 103   StringRefMemoryObject(StringRef bytes) : Bytes(bytes) {}
 104
 105   uint64_t getBase() const { return 0; }
 106   uint64_t getExtent() const { return Bytes.size(); }
 107
 108   int readByte(uint64_t Addr, uint8_t *Byte) const {
 109     if (Addr > getExtent())
 110       return -1;
 111     *Byte = Bytes[Addr];
 112     return 0;
 113   }
 114 };
 115 }
 116
 117 static void DumpBytes(StringRef bytes) {
 118   static char hex_rep[] = "0123456789abcdef";
 119   // FIXME: The real way to do this is to figure out the longest instruction
 120   //        and align to that size before printing. I'll fix this when I get
 121   //        around to outputting relocations.
 122   // 15 is the longest x86 instruction
 123   // 3 is for the hex rep of a byte + a space.
 124   // 1 is for the null terminator.
 125   enum { OutputSize = (15 * 3) + 1 };
 126   char output[OutputSize];
 127
 128   assert(bytes.size() <= 15
 129     && "DumpBytes only supports instructions of up to 15 bytes");
 130   memset(output, ' ', sizeof(output));
 131   unsigned index = 0;
 132   for (StringRef::iterator i = bytes.begin(),
 133                            e = bytes.end(); i != e; ++i) {
 134     output[index] = hex_rep[(*i & 0xF0) >> 4];
 135     output[index + 1] = hex_rep[*i & 0xF];
 136     index += 3;
 137   }
 138
 139   output[sizeof(output) - 1] = 0;
 140   outs() << output;
 141 }
 142
 143 static void DisassembleInput(const StringRef &Filename) {
 144   OwningPtr<MemoryBuffer> Buff;
 145
 146   if (error_code ec = MemoryBuffer::getFileOrSTDIN(Filename, Buff)) {
 147     errs() << ToolName << ": " << Filename << ": " << ec.message() << "\n";
 148     return;
 149   }
 150
 151   OwningPtr<ObjectFile> Obj(ObjectFile::createObjectFile(Buff.take()));
 152
 153   const Target *TheTarget = GetTarget(Obj.get());
 154   if (!TheTarget) {
 155     // GetTarget prints out stuff.
 156     return;
 157   }
 158
 159   outs() << '\n';
 160   outs() << Filename
 161          << ":\tfile format " << Obj->getFileFormatName() << "\n\n\n";
 162
 163   error_code ec;
 164   for (ObjectFile::section_iterator i = Obj->begin_sections(),
 165                                     e = Obj->end_sections();
 166                                     i != e; i.increment(ec)) {
 167     if (error(ec)) break;
 168     bool text;
 169     if (error(i->isText(text))) break;
 170     if (!text) continue;
 171
 172     StringRef name;
 173     if (error(i->getName(name))) break;
 174     outs() << "Disassembly of section " << name << ":\n\n";
 175
 176     // Set up disassembler.
 177     OwningPtr<const MCAsmInfo> AsmInfo(TheTarget->createAsmInfo(TripleName));
 178
 179     if (!AsmInfo) {
 180       errs() << "error: no assembly info for target " << TripleName << "\n";
 181       return;
 182     }
 183
 184     OwningPtr<const MCDisassembler> DisAsm(TheTarget->createMCDisassembler());
 185     if (!DisAsm) {
 186       errs() << "error: no disassembler for target " << TripleName << "\n";
 187       return;
 188     }
 189
 190     int AsmPrinterVariant = AsmInfo->getAssemblerDialect();
 191     OwningPtr<MCInstPrinter> IP(TheTarget->createMCInstPrinter(
 192                                   AsmPrinterVariant, *AsmInfo));
 193     if (!IP) {
 194       errs() << "error: no instruction printer for target " << TripleName << '\n';
 195       return;
 196     }
 197
 198     StringRef Bytes;
 199     if (error(i->getContents(Bytes))) break;
 200     StringRefMemoryObject memoryObject(Bytes);
 201     uint64_t Size;
 202     uint64_t Index;
 203
 204     for (Index = 0; Index < Bytes.size(); Index += Size) {
 205       MCInst Inst;
 206
 207 #     ifndef NDEBUG
 208       raw_ostream &DebugOut = DebugFlag ? dbgs() : nulls();
 209 #     else
 210       raw_ostream &DebugOut = nulls();
 211 #     endif
 212
 213       if (DisAsm->getInstruction(Inst, Size, memoryObject, Index, DebugOut)) {
 214         uint64_t addr;
 215         if (error(i->getAddress(addr))) break;
 216         outs() << format("%8x:\t", addr + Index);
 217         DumpBytes(StringRef(Bytes.data() + Index, Size));
 218         IP->printInst(&Inst, outs());
 219         outs() << "\n";
 220       } else {
 221         errs() << ToolName << ": warning: invalid instruction encoding\n";
 222         if (Size == 0)
 223           Size = 1; // skip illegible bytes
 224       }
 225     }
 226   }
 227 }
 228
 229 int main(int argc, char **argv) {
 230   // Print a stack trace if we signal out.
 231   sys::PrintStackTraceOnErrorSignal();
 232   PrettyStackTraceProgram X(argc, argv);
 233   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
 234
 235   // Initialize targets and assembly printers/parsers.
 236   llvm::InitializeAllTargetInfos();
 237   // FIXME: We shouldn't need to initialize the Target(Machine)s.
 238   llvm::InitializeAllTargets();
 239   llvm::InitializeAllAsmPrinters();
 240   llvm::InitializeAllAsmParsers();
 241   llvm::InitializeAllDisassemblers();
 242
 243   cl::ParseCommandLineOptions(argc, argv, "llvm object file dumper\n");
 244   TripleName = Triple::normalize(TripleName);
 245
 246   ToolName = argv[0];
 247
 248   // Defaults to a.out if no filenames specified.
 249   if (InputFilenames.size() == 0)
 250     InputFilenames.push_back("a.out");
 251
 252   // -d is the only flag that is currently implemented, so just print help if
 253   // it is not set.
 254   if (!Disassemble) {
 255     cl::PrintHelpMessage();
 256     return 2;
 257   }
 258
 259   std::for_each(InputFilenames.begin(), InputFilenames.end(),
 260                 DisassembleInput);
 261
 262   return 0;
 263 }