tools/llvm-objdump/ELFDump.cpp

   1 //===-- ELFDump.cpp - ELF-specific dumper -----------------------*- C++ -*-===//
   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 /// \file
  11 /// This file implements the ELF-specific dumper for llvm-objdump.
  12 ///
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm-objdump.h"
  16 #include "llvm/Object/ELFObjectFile.h"
  17 #include "llvm/Support/Format.h"
  18 #include "llvm/Support/MathExtras.h"
  19 #include "llvm/Support/raw_ostream.h"
  20
  21 using namespace llvm;
  22 using namespace llvm::object;
  23
  24 template <class ELFT>
  25 Expected<StringRef> getDynamicStrTab(const ELFFile<ELFT> *Elf) {
  26   typedef ELFFile<ELFT> ELFO;
  27
  28   auto DynamicEntriesOrError = Elf->dynamicEntries();
  29   if (!DynamicEntriesOrError)
  30     return DynamicEntriesOrError.takeError();
  31
  32   for (const typename ELFO::Elf_Dyn &Dyn : *DynamicEntriesOrError) {
  33     if (Dyn.d_tag == ELF::DT_STRTAB) {
  34       auto MappedAddrOrError = Elf->toMappedAddr(Dyn.getPtr());
  35       if (!MappedAddrOrError)
  36         consumeError(MappedAddrOrError.takeError());
  37       return StringRef(reinterpret_cast<const char *>(*MappedAddrOrError));
  38     }
  39   }
  40
  41   // If the dynamic segment is not present, we fall back on the sections.
  42   auto SectionsOrError = Elf->sections();
  43   if (!SectionsOrError)
  44     return SectionsOrError.takeError();
  45
  46   for (const typename ELFO::Elf_Shdr &Sec : *SectionsOrError) {
  47     if (Sec.sh_type == ELF::SHT_DYNSYM)
  48       return Elf->getStringTableForSymtab(Sec);
  49   }
  50
  51   return createError("dynamic string table not found");
  52 }
  53
  54 template <class ELFT>
  55 void printDynamicSection(const ELFFile<ELFT> *Elf, StringRef Filename) {
  56   auto ProgramHeaderOrError = Elf->program_headers();
  57   if (!ProgramHeaderOrError)
  58     report_error(Filename, ProgramHeaderOrError.takeError());
  59
  60   auto DynamicEntriesOrError = Elf->dynamicEntries();
  61   if (!DynamicEntriesOrError)
  62     report_error(Filename, DynamicEntriesOrError.takeError());
  63
  64   outs() << "Dynamic Section:\n";
  65   for (const auto &Dyn : *DynamicEntriesOrError) {
  66     if (Dyn.d_tag == ELF::DT_NULL)
  67       continue;
  68
  69     StringRef Str = StringRef(Elf->getDynamicTagAsString(Dyn.d_tag));
  70
  71     if (Str.empty()) {
  72       std::string HexStr = utohexstr(static_cast<uint64_t>(Dyn.d_tag), true);
  73       outs() << format("  0x%-19s", HexStr.c_str());
  74     } else {
  75       // We use "-21" in order to match GNU objdump's output.
  76       outs() << format("  %-21s", Str.data());
  77     }
  78
  79     const char *Fmt =
  80         ELFT::Is64Bits ? "0x%016" PRIx64 "\n" : "0x%08" PRIx64 "\n";
  81     if (Dyn.d_tag == ELF::DT_NEEDED) {
  82       Expected<StringRef> StrTabOrErr = getDynamicStrTab(Elf);
  83       if (StrTabOrErr) {
  84         const char *Data = StrTabOrErr.get().data();
  85         outs() << (Data + Dyn.d_un.d_val) << "\n";
  86         continue;
  87       }
  88       warn(errorToErrorCode(StrTabOrErr.takeError()).message());
  89       consumeError(StrTabOrErr.takeError());
  90     }
  91     outs() << format(Fmt, (uint64_t)Dyn.d_un.d_val);
  92   }
  93 }
  94
  95 template <class ELFT> void printProgramHeaders(const ELFFile<ELFT> *o) {
  96   typedef ELFFile<ELFT> ELFO;
  97   outs() << "Program Header:\n";
  98   auto ProgramHeaderOrError = o->program_headers();
  99   if (!ProgramHeaderOrError)
 100     report_fatal_error(
 101         errorToErrorCode(ProgramHeaderOrError.takeError()).message());
 102   for (const typename ELFO::Elf_Phdr &Phdr : *ProgramHeaderOrError) {
 103     switch (Phdr.p_type) {
 104     case ELF::PT_DYNAMIC:
 105       outs() << " DYNAMIC ";
 106       break;
 107     case ELF::PT_GNU_EH_FRAME:
 108       outs() << "EH_FRAME ";
 109       break;
 110     case ELF::PT_GNU_RELRO:
 111       outs() << "   RELRO ";
 112       break;
 113     case ELF::PT_GNU_STACK:
 114       outs() << "   STACK ";
 115       break;
 116     case ELF::PT_INTERP:
 117       outs() << "  INTERP ";
 118       break;
 119     case ELF::PT_LOAD:
 120       outs() << "    LOAD ";
 121       break;
 122     case ELF::PT_NOTE:
 123       outs() << "    NOTE ";
 124       break;
 125     case ELF::PT_OPENBSD_BOOTDATA:
 126       outs() << "    OPENBSD_BOOTDATA ";
 127       break;
 128     case ELF::PT_OPENBSD_RANDOMIZE:
 129       outs() << "    OPENBSD_RANDOMIZE ";
 130       break;
 131     case ELF::PT_OPENBSD_WXNEEDED:
 132       outs() << "    OPENBSD_WXNEEDED ";
 133       break;
 134     case ELF::PT_PHDR:
 135       outs() << "    PHDR ";
 136       break;
 137     case ELF::PT_TLS:
 138       outs() << "    TLS ";
 139       break;
 140     default:
 141       outs() << " UNKNOWN ";
 142     }
 143
 144     const char *Fmt = ELFT::Is64Bits ? "0x%016" PRIx64 " " : "0x%08" PRIx64 " ";
 145
 146     outs() << "off    " << format(Fmt, (uint64_t)Phdr.p_offset) << "vaddr "
 147            << format(Fmt, (uint64_t)Phdr.p_vaddr) << "paddr "
 148            << format(Fmt, (uint64_t)Phdr.p_paddr)
 149            << format("align 2**%u\n",
 150                      countTrailingZeros<uint64_t>(Phdr.p_align))
 151            << "         filesz " << format(Fmt, (uint64_t)Phdr.p_filesz)
 152            << "memsz " << format(Fmt, (uint64_t)Phdr.p_memsz) << "flags "
 153            << ((Phdr.p_flags & ELF::PF_R) ? "r" : "-")
 154            << ((Phdr.p_flags & ELF::PF_W) ? "w" : "-")
 155            << ((Phdr.p_flags & ELF::PF_X) ? "x" : "-") << "\n";
 156   }
 157   outs() << "\n";
 158 }
 159
 160 void llvm::printELFFileHeader(const object::ObjectFile *Obj) {
 161   if (const auto *ELFObj = dyn_cast<ELF32LEObjectFile>(Obj))
 162     printProgramHeaders(ELFObj->getELFFile());
 163   else if (const auto *ELFObj = dyn_cast<ELF32BEObjectFile>(Obj))
 164     printProgramHeaders(ELFObj->getELFFile());
 165   else if (const auto *ELFObj = dyn_cast<ELF64LEObjectFile>(Obj))
 166     printProgramHeaders(ELFObj->getELFFile());
 167   else if (const auto *ELFObj = dyn_cast<ELF64BEObjectFile>(Obj))
 168     printProgramHeaders(ELFObj->getELFFile());
 169 }
 170
 171 void llvm::printELFDynamicSection(const object::ObjectFile *Obj) {
 172   if (const auto *ELFObj = dyn_cast<ELF32LEObjectFile>(Obj))
 173     printDynamicSection(ELFObj->getELFFile(), Obj->getFileName());
 174   else if (const auto *ELFObj = dyn_cast<ELF32BEObjectFile>(Obj))
 175     printDynamicSection(ELFObj->getELFFile(), Obj->getFileName());
 176   else if (const auto *ELFObj = dyn_cast<ELF64LEObjectFile>(Obj))
 177     printDynamicSection(ELFObj->getELFFile(), Obj->getFileName());
 178   else if (const auto *ELFObj = dyn_cast<ELF64BEObjectFile>(Obj))
 179     printDynamicSection(ELFObj->getELFFile(), Obj->getFileName());
 180 }