lib/Object/ELFObjectFile.cpp

   1 //===- ELFObjectFile.cpp - ELF object file implementation -------*- 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 // This file defines the ELFObjectFile class.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/ADT/SmallVector.h"
  15 #include "llvm/ADT/StringSwitch.h"
  16 #include "llvm/ADT/Triple.h"
  17 #include "llvm/Object/ObjectFile.h"
  18 #include "llvm/Support/ELF.h"
  19 #include "llvm/Support/Endian.h"
  20 #include "llvm/Support/ErrorHandling.h"
  21 #include "llvm/Support/MemoryBuffer.h"
  22 #include <limits>
  23 #include <utility>
  24
  25 using namespace llvm;
  26 using namespace object;
  27
  28 // Templates to choose Elf_Addr and Elf_Off depending on is64Bits.
  29 namespace {
  30 template<support::endianness target_endianness>
  31 struct ELFDataTypeTypedefHelperCommon {
  32   typedef support::detail::packed_endian_specific_integral
  33     <uint16_t, target_endianness, support::aligned> Elf_Half;
  34   typedef support::detail::packed_endian_specific_integral
  35     <uint32_t, target_endianness, support::aligned> Elf_Word;
  36   typedef support::detail::packed_endian_specific_integral
  37     <int32_t, target_endianness, support::aligned> Elf_Sword;
  38   typedef support::detail::packed_endian_specific_integral
  39     <uint64_t, target_endianness, support::aligned> Elf_Xword;
  40   typedef support::detail::packed_endian_specific_integral
  41     <int64_t, target_endianness, support::aligned> Elf_Sxword;
  42 };
  43 }
  44
  45 namespace {
  46 template<support::endianness target_endianness, bool is64Bits>
  47 struct ELFDataTypeTypedefHelper;
  48
  49 /// ELF 32bit types.
  50 template<support::endianness target_endianness>
  51 struct ELFDataTypeTypedefHelper<target_endianness, false>
  52   : ELFDataTypeTypedefHelperCommon<target_endianness> {
  53   typedef support::detail::packed_endian_specific_integral
  54     <uint32_t, target_endianness, support::aligned> Elf_Addr;
  55   typedef support::detail::packed_endian_specific_integral
  56     <uint32_t, target_endianness, support::aligned> Elf_Off;
  57 };
  58
  59 /// ELF 64bit types.
  60 template<support::endianness target_endianness>
  61 struct ELFDataTypeTypedefHelper<target_endianness, true>
  62   : ELFDataTypeTypedefHelperCommon<target_endianness>{
  63   typedef support::detail::packed_endian_specific_integral
  64     <uint64_t, target_endianness, support::aligned> Elf_Addr;
  65   typedef support::detail::packed_endian_specific_integral
  66     <uint64_t, target_endianness, support::aligned> Elf_Off;
  67 };
  68 }
  69
  70 // I really don't like doing this, but the alternative is copypasta.
  71 #define LLVM_ELF_IMPORT_TYPES(target_endianness, is64Bits) \
  72 typedef typename \
  73   ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Addr Elf_Addr; \
  74 typedef typename \
  75   ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Off Elf_Off; \
  76 typedef typename \
  77   ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Half Elf_Half; \
  78 typedef typename \
  79   ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Word Elf_Word; \
  80 typedef typename \
  81   ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Sword Elf_Sword; \
  82 typedef typename \
  83   ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Xword Elf_Xword; \
  84 typedef typename \
  85   ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Sxword Elf_Sxword;
  86
  87   // Section header.
  88 namespace {
  89 template<support::endianness target_endianness, bool is64Bits>
  90 struct Elf_Shdr_Base;
  91
  92 template<support::endianness target_endianness>
  93 struct Elf_Shdr_Base<target_endianness, false> {
  94   LLVM_ELF_IMPORT_TYPES(target_endianness, false)
  95   Elf_Word sh_name;     // Section name (index into string table)
  96   Elf_Word sh_type;     // Section type (SHT_*)
  97   Elf_Word sh_flags;    // Section flags (SHF_*)
  98   Elf_Addr sh_addr;     // Address where section is to be loaded
  99   Elf_Off  sh_offset;   // File offset of section data, in bytes
 100   Elf_Word sh_size;     // Size of section, in bytes
 101   Elf_Word sh_link;     // Section type-specific header table index link
 102   Elf_Word sh_info;     // Section type-specific extra information
 103   Elf_Word sh_addralign;// Section address alignment
 104   Elf_Word sh_entsize;  // Size of records contained within the section
 105 };
 106
 107 template<support::endianness target_endianness>
 108 struct Elf_Shdr_Base<target_endianness, true> {
 109   LLVM_ELF_IMPORT_TYPES(target_endianness, true)
 110   Elf_Word  sh_name;     // Section name (index into string table)
 111   Elf_Word  sh_type;     // Section type (SHT_*)
 112   Elf_Xword sh_flags;    // Section flags (SHF_*)
 113   Elf_Addr  sh_addr;     // Address where section is to be loaded
 114   Elf_Off   sh_offset;   // File offset of section data, in bytes
 115   Elf_Xword sh_size;     // Size of section, in bytes
 116   Elf_Word  sh_link;     // Section type-specific header table index link
 117   Elf_Word  sh_info;     // Section type-specific extra information
 118   Elf_Xword sh_addralign;// Section address alignment
 119   Elf_Xword sh_entsize;  // Size of records contained within the section
 120 };
 121
 122 template<support::endianness target_endianness, bool is64Bits>
 123 struct Elf_Shdr_Impl : Elf_Shdr_Base<target_endianness, is64Bits> {
 124   using Elf_Shdr_Base<target_endianness, is64Bits>::sh_entsize;
 125   using Elf_Shdr_Base<target_endianness, is64Bits>::sh_size;
 126
 127   /// @brief Get the number of entities this section contains if it has any.
 128   unsigned getEntityCount() const {
 129     if (sh_entsize == 0)
 130       return 0;
 131     return sh_size / sh_entsize;
 132   }
 133 };
 134 }
 135
 136 namespace {
 137 template<support::endianness target_endianness, bool is64Bits>
 138 struct Elf_Sym_Base;
 139
 140 template<support::endianness target_endianness>
 141 struct Elf_Sym_Base<target_endianness, false> {
 142   LLVM_ELF_IMPORT_TYPES(target_endianness, false)
 143   Elf_Word      st_name;  // Symbol name (index into string table)
 144   Elf_Addr      st_value; // Value or address associated with the symbol
 145   Elf_Word      st_size;  // Size of the symbol
 146   unsigned char st_info;  // Symbol's type and binding attributes
 147   unsigned char st_other; // Must be zero; reserved
 148   Elf_Half      st_shndx; // Which section (header table index) it's defined in
 149 };
 150
 151 template<support::endianness target_endianness>
 152 struct Elf_Sym_Base<target_endianness, true> {
 153   LLVM_ELF_IMPORT_TYPES(target_endianness, true)
 154   Elf_Word      st_name;  // Symbol name (index into string table)
 155   unsigned char st_info;  // Symbol's type and binding attributes
 156   unsigned char st_other; // Must be zero; reserved
 157   Elf_Half      st_shndx; // Which section (header table index) it's defined in
 158   Elf_Addr      st_value; // Value or address associated with the symbol
 159   Elf_Xword     st_size;  // Size of the symbol
 160 };
 161
 162 template<support::endianness target_endianness, bool is64Bits>
 163 struct Elf_Sym_Impl : Elf_Sym_Base<target_endianness, is64Bits> {
 164   using Elf_Sym_Base<target_endianness, is64Bits>::st_info;
 165
 166   // These accessors and mutators correspond to the ELF32_ST_BIND,
 167   // ELF32_ST_TYPE, and ELF32_ST_INFO macros defined in the ELF specification:
 168   unsigned char getBinding() const { return st_info >> 4; }
 169   unsigned char getType() const { return st_info & 0x0f; }
 170   void setBinding(unsigned char b) { setBindingAndType(b, getType()); }
 171   void setType(unsigned char t) { setBindingAndType(getBinding(), t); }
 172   void setBindingAndType(unsigned char b, unsigned char t) {
 173     st_info = (b << 4) + (t & 0x0f);
 174   }
 175 };
 176 }
 177
 178 namespace {
 179 template<support::endianness target_endianness, bool is64Bits>
 180 class ELFObjectFile : public ObjectFile {
 181   LLVM_ELF_IMPORT_TYPES(target_endianness, is64Bits)
 182
 183   typedef Elf_Shdr_Impl<target_endianness, is64Bits> Elf_Shdr;
 184   typedef Elf_Sym_Impl<target_endianness, is64Bits> Elf_Sym;
 185
 186   struct Elf_Ehdr {
 187     unsigned char e_ident[ELF::EI_NIDENT]; // ELF Identification bytes
 188     Elf_Half e_type;     // Type of file (see ET_*)
 189     Elf_Half e_machine;  // Required architecture for this file (see EM_*)
 190     Elf_Word e_version;  // Must be equal to 1
 191     Elf_Addr e_entry;    // Address to jump to in order to start program
 192     Elf_Off  e_phoff;    // Program header table's file offset, in bytes
 193     Elf_Off  e_shoff;    // Section header table's file offset, in bytes
 194     Elf_Word e_flags;    // Processor-specific flags
 195     Elf_Half e_ehsize;   // Size of ELF header, in bytes
 196     Elf_Half e_phentsize;// Size of an entry in the program header table
 197     Elf_Half e_phnum;    // Number of entries in the program header table
 198     Elf_Half e_shentsize;// Size of an entry in the section header table
 199     Elf_Half e_shnum;    // Number of entries in the section header table
 200     Elf_Half e_shstrndx; // Section header table index of section name
 201                                   // string table
 202     bool checkMagic() const {
 203       return (memcmp(e_ident, ELF::ElfMagic, strlen(ELF::ElfMagic))) == 0;
 204     }
 205     unsigned char getFileClass() const { return e_ident[ELF::EI_CLASS]; }
 206     unsigned char getDataEncoding() const { return e_ident[ELF::EI_DATA]; }
 207   };
 208
 209   typedef SmallVector<const Elf_Shdr*, 1> SymbolTableSections_t;
 210
 211   const Elf_Ehdr *Header;
 212   const Elf_Shdr *SectionHeaderTable;
 213   const Elf_Shdr *dot_shstrtab_sec; // Section header string table.
 214   const Elf_Shdr *dot_strtab_sec;   // Symbol header string table.
 215   SymbolTableSections_t SymbolTableSections;
 216
 217   void            validateSymbol(DataRefImpl Symb) const;
 218   const Elf_Sym  *getSymbol(DataRefImpl Symb) const;
 219   const Elf_Shdr *getSection(DataRefImpl index) const;
 220   const Elf_Shdr *getSection(uint16_t index) const;
 221   const char     *getString(uint16_t section, uint32_t offset) const;
 222   const char     *getString(const Elf_Shdr *section, uint32_t offset) const;
 223
 224 protected:
 225   virtual SymbolRef getSymbolNext(DataRefImpl Symb) const;
 226   virtual StringRef getSymbolName(DataRefImpl Symb) const;
 227   virtual uint64_t  getSymbolAddress(DataRefImpl Symb) const;
 228   virtual uint64_t  getSymbolSize(DataRefImpl Symb) const;
 229   virtual char      getSymbolNMTypeChar(DataRefImpl Symb) const;
 230   virtual bool      isSymbolInternal(DataRefImpl Symb) const;
 231
 232   virtual SectionRef getSectionNext(DataRefImpl Sec) const;
 233   virtual StringRef  getSectionName(DataRefImpl Sec) const;
 234   virtual uint64_t   getSectionAddress(DataRefImpl Sec) const;
 235   virtual uint64_t   getSectionSize(DataRefImpl Sec) const;
 236   virtual StringRef  getSectionContents(DataRefImpl Sec) const;
 237   virtual bool       isSectionText(DataRefImpl Sec) const;
 238
 239 public:
 240   ELFObjectFile(MemoryBuffer *Object);
 241   virtual symbol_iterator begin_symbols() const;
 242   virtual symbol_iterator end_symbols() const;
 243   virtual section_iterator begin_sections() const;
 244   virtual section_iterator end_sections() const;
 245
 246   virtual uint8_t getBytesInAddress() const;
 247   virtual StringRef getFileFormatName() const;
 248   virtual unsigned getArch() const;
 249 };
 250 } // end namespace
 251
 252 template<support::endianness target_endianness, bool is64Bits>
 253 void ELFObjectFile<target_endianness, is64Bits>
 254                   ::validateSymbol(DataRefImpl Symb) const {
 255   const Elf_Sym  *symb = getSymbol(Symb);
 256   const Elf_Shdr *SymbolTableSection = SymbolTableSections[Symb.d.b];
 257   // FIXME: We really need to do proper error handling in the case of an invalid
 258   //        input file. Because we don't use exceptions, I think we'll just pass
 259   //        an error object around.
 260   if (!(  symb
 261         && SymbolTableSection
 262         && symb >= (const Elf_Sym*)(base
 263                    + SymbolTableSection->sh_offset)
 264         && symb <  (const Elf_Sym*)(base
 265                    + SymbolTableSection->sh_offset
 266                    + SymbolTableSection->sh_size)))
 267     // FIXME: Proper error handling.
 268     report_fatal_error("Symb must point to a valid symbol!");
 269 }
 270
 271 template<support::endianness target_endianness, bool is64Bits>
 272 SymbolRef ELFObjectFile<target_endianness, is64Bits>
 273                        ::getSymbolNext(DataRefImpl Symb) const {
 274   validateSymbol(Symb);
 275   const Elf_Shdr *SymbolTableSection = SymbolTableSections[Symb.d.b];
 276
 277   ++Symb.d.a;
 278   // Check to see if we are at the end of this symbol table.
 279   if (Symb.d.a >= SymbolTableSection->getEntityCount()) {
 280     // We are at the end. If there are other symbol tables, jump to them.
 281     ++Symb.d.b;
 282     Symb.d.a = 1; // The 0th symbol in ELF is fake.
 283     // Otherwise return the terminator.
 284     if (Symb.d.b >= SymbolTableSections.size()) {
 285       Symb.d.a = std::numeric_limits<uint32_t>::max();
 286       Symb.d.b = std::numeric_limits<uint32_t>::max();
 287     }
 288   }
 289
 290   return SymbolRef(Symb, this);
 291 }
 292
 293 template<support::endianness target_endianness, bool is64Bits>
 294 StringRef ELFObjectFile<target_endianness, is64Bits>
 295                        ::getSymbolName(DataRefImpl Symb) const {
 296   validateSymbol(Symb);
 297   const Elf_Sym  *symb = getSymbol(Symb);
 298   if (symb->st_name == 0) {
 299     const Elf_Shdr *section = getSection(symb->st_shndx);
 300     if (!section)
 301       return "";
 302     return getString(dot_shstrtab_sec, section->sh_name);
 303   }
 304
 305   // Use the default symbol table name section.
 306   return getString(dot_strtab_sec, symb->st_name);
 307 }
 308
 309 template<support::endianness target_endianness, bool is64Bits>
 310 uint64_t ELFObjectFile<target_endianness, is64Bits>
 311                       ::getSymbolAddress(DataRefImpl Symb) const {
 312   validateSymbol(Symb);
 313   const Elf_Sym  *symb = getSymbol(Symb);
 314   const Elf_Shdr *Section;
 315   switch (symb->st_shndx) {
 316   case ELF::SHN_COMMON:
 317    // Undefined symbols have no address yet.
 318   case ELF::SHN_UNDEF: return UnknownAddressOrSize;
 319   case ELF::SHN_ABS: return symb->st_value;
 320   default: Section = getSection(symb->st_shndx);
 321   }
 322
 323   switch (symb->getType()) {
 324   case ELF::STT_SECTION: return Section ? Section->sh_addr
 325                                         : UnknownAddressOrSize;
 326   case ELF::STT_FUNC:
 327   case ELF::STT_OBJECT:
 328   case ELF::STT_NOTYPE:
 329     return symb->st_value;
 330   default: return UnknownAddressOrSize;
 331   }
 332 }
 333
 334 template<support::endianness target_endianness, bool is64Bits>
 335 uint64_t ELFObjectFile<target_endianness, is64Bits>
 336                       ::getSymbolSize(DataRefImpl Symb) const {
 337   validateSymbol(Symb);
 338   const Elf_Sym  *symb = getSymbol(Symb);
 339   if (symb->st_size == 0)
 340     return UnknownAddressOrSize;
 341   return symb->st_size;
 342 }
 343
 344 template<support::endianness target_endianness, bool is64Bits>
 345 char ELFObjectFile<target_endianness, is64Bits>
 346                   ::getSymbolNMTypeChar(DataRefImpl Symb) const {
 347   validateSymbol(Symb);
 348   const Elf_Sym  *symb = getSymbol(Symb);
 349   const Elf_Shdr *Section = getSection(symb->st_shndx);
 350
 351   char ret = '?';
 352
 353   if (Section) {
 354     switch (Section->sh_type) {
 355     case ELF::SHT_PROGBITS:
 356     case ELF::SHT_DYNAMIC:
 357       switch (Section->sh_flags) {
 358       case (ELF::SHF_ALLOC | ELF::SHF_EXECINSTR):
 359         ret = 't'; break;
 360       case (ELF::SHF_ALLOC | ELF::SHF_WRITE):
 361         ret = 'd'; break;
 362       case ELF::SHF_ALLOC:
 363       case (ELF::SHF_ALLOC | ELF::SHF_MERGE):
 364       case (ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::SHF_STRINGS):
 365         ret = 'r'; break;
 366       }
 367       break;
 368     case ELF::SHT_NOBITS: ret = 'b';
 369     }
 370   }
 371
 372   switch (symb->st_shndx) {
 373   case ELF::SHN_UNDEF:
 374     if (ret == '?')
 375       ret = 'U';
 376     break;
 377   case ELF::SHN_ABS: ret = 'a'; break;
 378   case ELF::SHN_COMMON: ret = 'c'; break;
 379   }
 380
 381   switch (symb->getBinding()) {
 382   case ELF::STB_GLOBAL: ret = ::toupper(ret); break;
 383   case ELF::STB_WEAK:
 384     if (symb->st_shndx == ELF::SHN_UNDEF)
 385       ret = 'w';
 386     else
 387       if (symb->getType() == ELF::STT_OBJECT)
 388         ret = 'V';
 389       else
 390         ret = 'W';
 391   }
 392
 393   if (ret == '?' && symb->getType() == ELF::STT_SECTION)
 394     return StringSwitch<char>(getSymbolName(Symb))
 395       .StartsWith(".debug", 'N')
 396       .StartsWith(".note", 'n');
 397
 398   return ret;
 399 }
 400
 401 template<support::endianness target_endianness, bool is64Bits>
 402 bool ELFObjectFile<target_endianness, is64Bits>
 403                   ::isSymbolInternal(DataRefImpl Symb) const {
 404   validateSymbol(Symb);
 405   const Elf_Sym  *symb = getSymbol(Symb);
 406
 407   if (  symb->getType() == ELF::STT_FILE
 408      || symb->getType() == ELF::STT_SECTION)
 409     return true;
 410   return false;
 411 }
 412
 413 template<support::endianness target_endianness, bool is64Bits>
 414 SectionRef ELFObjectFile<target_endianness, is64Bits>
 415                         ::getSectionNext(DataRefImpl Sec) const {
 416   const uint8_t *sec = reinterpret_cast<const uint8_t *>(Sec.p);
 417   sec += Header->e_shentsize;
 418   Sec.p = reinterpret_cast<intptr_t>(sec);
 419   return SectionRef(Sec, this);
 420 }
 421
 422 template<support::endianness target_endianness, bool is64Bits>
 423 StringRef ELFObjectFile<target_endianness, is64Bits>
 424                        ::getSectionName(DataRefImpl Sec) const {
 425   const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p);
 426   return StringRef(getString(dot_shstrtab_sec, sec->sh_name));
 427 }
 428
 429 template<support::endianness target_endianness, bool is64Bits>
 430 uint64_t ELFObjectFile<target_endianness, is64Bits>
 431                       ::getSectionAddress(DataRefImpl Sec) const {
 432   const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p);
 433   return sec->sh_addr;
 434 }
 435
 436 template<support::endianness target_endianness, bool is64Bits>
 437 uint64_t ELFObjectFile<target_endianness, is64Bits>
 438                       ::getSectionSize(DataRefImpl Sec) const {
 439   const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p);
 440   return sec->sh_size;
 441 }
 442
 443 template<support::endianness target_endianness, bool is64Bits>
 444 StringRef ELFObjectFile<target_endianness, is64Bits>
 445                        ::getSectionContents(DataRefImpl Sec) const {
 446   const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p);
 447   const char *start = (char*)base + sec->sh_offset;
 448   return StringRef(start, sec->sh_size);
 449 }
 450
 451 template<support::endianness target_endianness, bool is64Bits>
 452 bool ELFObjectFile<target_endianness, is64Bits>
 453                   ::isSectionText(DataRefImpl Sec) const {
 454   const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p);
 455   if (sec->sh_flags & ELF::SHF_EXECINSTR)
 456     return true;
 457   return false;
 458 }
 459
 460 template<support::endianness target_endianness, bool is64Bits>
 461 ELFObjectFile<target_endianness, is64Bits>::ELFObjectFile(MemoryBuffer *Object)
 462   : ObjectFile(Object)
 463   , SectionHeaderTable(0)
 464   , dot_shstrtab_sec(0)
 465   , dot_strtab_sec(0) {
 466   Header = reinterpret_cast<const Elf_Ehdr *>(base);
 467
 468   if (Header->e_shoff == 0)
 469     return;
 470
 471   SectionHeaderTable =
 472     reinterpret_cast<const Elf_Shdr *>(base + Header->e_shoff);
 473   uint32_t SectionTableSize = Header->e_shnum * Header->e_shentsize;
 474   if (!(  (const uint8_t *)SectionHeaderTable + SectionTableSize
 475          <= base + MapFile->getBufferSize()))
 476     // FIXME: Proper error handling.
 477     report_fatal_error("Section table goes past end of file!");
 478
 479
 480   // To find the symbol tables we walk the section table to find SHT_STMTAB.
 481   for (const char *i = reinterpret_cast<const char *>(SectionHeaderTable),
 482                   *e = i + Header->e_shnum * Header->e_shentsize;
 483                    i != e; i += Header->e_shentsize) {
 484     const Elf_Shdr *sh = reinterpret_cast<const Elf_Shdr*>(i);
 485     if (sh->sh_type == ELF::SHT_SYMTAB) {
 486       SymbolTableSections.push_back(sh);
 487     }
 488   }
 489
 490   // Get string table sections.
 491   dot_shstrtab_sec = getSection(Header->e_shstrndx);
 492   if (dot_shstrtab_sec) {
 493     // Verify that the last byte in the string table in a null.
 494     if (((const char*)base + dot_shstrtab_sec->sh_offset)
 495         [dot_shstrtab_sec->sh_size - 1] != 0)
 496       // FIXME: Proper error handling.
 497       report_fatal_error("String table must end with a null terminator!");
 498   }
 499
 500   // Merge this into the above loop.
 501   for (const char *i = reinterpret_cast<const char *>(SectionHeaderTable),
 502                   *e = i + Header->e_shnum * Header->e_shentsize;
 503                    i != e; i += Header->e_shentsize) {
 504     const Elf_Shdr *sh = reinterpret_cast<const Elf_Shdr*>(i);
 505     if (sh->sh_type == ELF::SHT_STRTAB) {
 506       StringRef SectionName(getString(dot_shstrtab_sec, sh->sh_name));
 507       if (SectionName == ".strtab") {
 508         if (dot_strtab_sec != 0)
 509           // FIXME: Proper error handling.
 510           report_fatal_error("Already found section named .strtab!");
 511         dot_strtab_sec = sh;
 512         const char *dot_strtab = (const char*)base + sh->sh_offset;
 513           if (dot_strtab[sh->sh_size - 1] != 0)
 514             // FIXME: Proper error handling.
 515             report_fatal_error("String table must end with a null terminator!");
 516       }
 517     }
 518   }
 519 }
 520
 521 template<support::endianness target_endianness, bool is64Bits>
 522 ObjectFile::symbol_iterator ELFObjectFile<target_endianness, is64Bits>
 523                                          ::begin_symbols() const {
 524   DataRefImpl SymbolData;
 525   memset(&SymbolData, 0, sizeof(SymbolData));
 526   if (SymbolTableSections.size() == 0) {
 527     SymbolData.d.a = std::numeric_limits<uint32_t>::max();
 528     SymbolData.d.b = std::numeric_limits<uint32_t>::max();
 529   } else {
 530     SymbolData.d.a = 1; // The 0th symbol in ELF is fake.
 531     SymbolData.d.b = 0;
 532   }
 533   return symbol_iterator(SymbolRef(SymbolData, this));
 534 }
 535
 536 template<support::endianness target_endianness, bool is64Bits>
 537 ObjectFile::symbol_iterator ELFObjectFile<target_endianness, is64Bits>
 538                                          ::end_symbols() const {
 539   DataRefImpl SymbolData;
 540   memset(&SymbolData, 0, sizeof(SymbolData));
 541   SymbolData.d.a = std::numeric_limits<uint32_t>::max();
 542   SymbolData.d.b = std::numeric_limits<uint32_t>::max();
 543   return symbol_iterator(SymbolRef(SymbolData, this));
 544 }
 545
 546 template<support::endianness target_endianness, bool is64Bits>
 547 ObjectFile::section_iterator ELFObjectFile<target_endianness, is64Bits>
 548                                           ::begin_sections() const {
 549   DataRefImpl ret;
 550   memset(&ret, 0, sizeof(DataRefImpl));
 551   ret.p = reinterpret_cast<intptr_t>(base + Header->e_shoff);
 552   return section_iterator(SectionRef(ret, this));
 553 }
 554
 555 template<support::endianness target_endianness, bool is64Bits>
 556 ObjectFile::section_iterator ELFObjectFile<target_endianness, is64Bits>
 557                                           ::end_sections() const {
 558   DataRefImpl ret;
 559   memset(&ret, 0, sizeof(DataRefImpl));
 560   ret.p = reinterpret_cast<intptr_t>(base
 561                                      + Header->e_shoff
 562                                      + (Header->e_shentsize * Header->e_shnum));
 563   return section_iterator(SectionRef(ret, this));
 564 }
 565
 566 template<support::endianness target_endianness, bool is64Bits>
 567 uint8_t ELFObjectFile<target_endianness, is64Bits>::getBytesInAddress() const {
 568   return is64Bits ? 8 : 4;
 569 }
 570
 571 template<support::endianness target_endianness, bool is64Bits>
 572 StringRef ELFObjectFile<target_endianness, is64Bits>
 573                        ::getFileFormatName() const {
 574   switch(Header->e_ident[ELF::EI_CLASS]) {
 575   case ELF::ELFCLASS32:
 576     switch(Header->e_machine) {
 577     case ELF::EM_386:
 578       return "ELF32-i386";
 579     case ELF::EM_X86_64:
 580       return "ELF32-x86-64";
 581     default:
 582       return "ELF32-unknown";
 583     }
 584   case ELF::ELFCLASS64:
 585     switch(Header->e_machine) {
 586     case ELF::EM_386:
 587       return "ELF64-i386";
 588     case ELF::EM_X86_64:
 589       return "ELF64-x86-64";
 590     default:
 591       return "ELF64-unknown";
 592     }
 593   default:
 594     // FIXME: Proper error handling.
 595     report_fatal_error("Invalid ELFCLASS!");
 596   }
 597 }
 598
 599 template<support::endianness target_endianness, bool is64Bits>
 600 unsigned ELFObjectFile<target_endianness, is64Bits>::getArch() const {
 601   switch(Header->e_machine) {
 602   case ELF::EM_386:
 603     return Triple::x86;
 604   case ELF::EM_X86_64:
 605     return Triple::x86_64;
 606   default:
 607     return Triple::UnknownArch;
 608   }
 609 }
 610
 611 template<support::endianness target_endianness, bool is64Bits>
 612 const typename ELFObjectFile<target_endianness, is64Bits>::Elf_Sym *
 613 ELFObjectFile<target_endianness, is64Bits>::getSymbol(DataRefImpl Symb) const {
 614   const Elf_Shdr *sec = SymbolTableSections[Symb.d.b];
 615   return reinterpret_cast<const Elf_Sym *>(
 616            base
 617            + sec->sh_offset
 618            + (Symb.d.a * sec->sh_entsize));
 619 }
 620
 621 template<support::endianness target_endianness, bool is64Bits>
 622 const typename ELFObjectFile<target_endianness, is64Bits>::Elf_Shdr *
 623 ELFObjectFile<target_endianness, is64Bits>::getSection(DataRefImpl Symb) const {
 624   const Elf_Shdr *sec = getSection(Symb.d.b);
 625   if (sec->sh_type != ELF::SHT_SYMTAB)
 626     // FIXME: Proper error handling.
 627     report_fatal_error("Invalid symbol table section!");
 628   return sec;
 629 }
 630
 631 template<support::endianness target_endianness, bool is64Bits>
 632 const typename ELFObjectFile<target_endianness, is64Bits>::Elf_Shdr *
 633 ELFObjectFile<target_endianness, is64Bits>::getSection(uint16_t index) const {
 634   if (index == 0 || index >= ELF::SHN_LORESERVE)
 635     return 0;
 636   if (!SectionHeaderTable || index >= Header->e_shnum)
 637     // FIXME: Proper error handling.
 638     report_fatal_error("Invalid section index!");
 639
 640   return reinterpret_cast<const Elf_Shdr *>(
 641          reinterpret_cast<const char *>(SectionHeaderTable)
 642          + (index * Header->e_shentsize));
 643 }
 644
 645 template<support::endianness target_endianness, bool is64Bits>
 646 const char *ELFObjectFile<target_endianness, is64Bits>
 647                          ::getString(uint16_t section,
 648                                      ELF::Elf32_Word offset) const {
 649   return getString(getSection(section), offset);
 650 }
 651
 652 template<support::endianness target_endianness, bool is64Bits>
 653 const char *ELFObjectFile<target_endianness, is64Bits>
 654                          ::getString(const Elf_Shdr *section,
 655                                      ELF::Elf32_Word offset) const {
 656   assert(section && section->sh_type == ELF::SHT_STRTAB && "Invalid section!");
 657   if (offset >= section->sh_size)
 658     // FIXME: Proper error handling.
 659     report_fatal_error("Sybol name offset outside of string table!");
 660   return (const char *)base + section->sh_offset + offset;
 661 }
 662
 663 // EI_CLASS, EI_DATA.
 664 static std::pair<unsigned char, unsigned char>
 665 getElfArchType(MemoryBuffer *Object) {
 666   if (Object->getBufferSize() < ELF::EI_NIDENT)
 667     return std::make_pair((uint8_t)ELF::ELFCLASSNONE,(uint8_t)ELF::ELFDATANONE);
 668   return std::make_pair( (uint8_t)Object->getBufferStart()[ELF::EI_CLASS]
 669                        , (uint8_t)Object->getBufferStart()[ELF::EI_DATA]);
 670 }
 671
 672 namespace llvm {
 673
 674   ObjectFile *ObjectFile::createELFObjectFile(MemoryBuffer *Object) {
 675     std::pair<unsigned char, unsigned char> Ident = getElfArchType(Object);
 676     if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2LSB)
 677       return new ELFObjectFile<support::little, false>(Object);
 678     else if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2MSB)
 679       return new ELFObjectFile<support::big, false>(Object);
 680     else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2LSB)
 681       return new ELFObjectFile<support::little, true>(Object);
 682     else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2MSB)
 683       return new ELFObjectFile<support::big, true>(Object);
 684     // FIXME: Proper error handling.
 685     report_fatal_error("Not an ELF object file!");
 686   }
 687
 688 } // end namespace llvm