lib/MC/ELFObjectWriter.cpp

   1 //===- lib/MC/ELFObjectWriter.cpp - ELF File Writer -------------------===//
   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 ELF object file writer information.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "ELFObjectWriter.h"
  15 #include "llvm/ADT/STLExtras.h"
  16 #include "llvm/ADT/StringMap.h"
  17 #include "llvm/ADT/Twine.h"
  18 #include "llvm/MC/MCAsmLayout.h"
  19 #include "llvm/MC/MCContext.h"
  20 #include "llvm/MC/MCExpr.h"
  21 #include "llvm/MC/MCSectionELF.h"
  22 #include "llvm/MC/MCValue.h"
  23 #include "llvm/Support/Debug.h"
  24 #include "llvm/Support/ErrorHandling.h"
  25 #include "llvm/Support/ELF.h"
  26 #include "llvm/Target/TargetAsmBackend.h"
  27 #include "llvm/ADT/StringSwitch.h"
  28 #include "llvm/Support/CommandLine.h"
  29 #include "llvm/ADT/Statistic.h"
  30
  31 #include "../Target/X86/X86FixupKinds.h"
  32 #include "../Target/ARM/ARMFixupKinds.h"
  33
  34 #include <vector>
  35 using namespace llvm;
  36
  37 #undef  DEBUG_TYPE
  38 #define DEBUG_TYPE "reloc-info"
  39
  40 bool ELFObjectWriter::isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind) {
  41   const MCFixupKindInfo &FKI =
  42     Asm.getBackend().getFixupKindInfo((MCFixupKind) Kind);
  43
  44   return FKI.Flags & MCFixupKindInfo::FKF_IsPCRel;
  45 }
  46
  47 bool ELFObjectWriter::RelocNeedsGOT(MCSymbolRefExpr::VariantKind Variant) {
  48   switch (Variant) {
  49   default:
  50     return false;
  51   case MCSymbolRefExpr::VK_GOT:
  52   case MCSymbolRefExpr::VK_PLT:
  53   case MCSymbolRefExpr::VK_GOTPCREL:
  54   case MCSymbolRefExpr::VK_GOTOFF:
  55   case MCSymbolRefExpr::VK_TPOFF:
  56   case MCSymbolRefExpr::VK_TLSGD:
  57   case MCSymbolRefExpr::VK_GOTTPOFF:
  58   case MCSymbolRefExpr::VK_INDNTPOFF:
  59   case MCSymbolRefExpr::VK_NTPOFF:
  60   case MCSymbolRefExpr::VK_GOTNTPOFF:
  61   case MCSymbolRefExpr::VK_TLSLDM:
  62   case MCSymbolRefExpr::VK_DTPOFF:
  63   case MCSymbolRefExpr::VK_TLSLD:
  64     return true;
  65   }
  66 }
  67
  68 ELFObjectWriter::~ELFObjectWriter()
  69 {}
  70
  71 // Emit the ELF header.
  72 void ELFObjectWriter::WriteHeader(uint64_t SectionDataSize,
  73                                   unsigned NumberOfSections) {
  74   // ELF Header
  75   // ----------
  76   //
  77   // Note
  78   // ----
  79   // emitWord method behaves differently for ELF32 and ELF64, writing
  80   // 4 bytes in the former and 8 in the latter.
  81
  82   Write8(0x7f); // e_ident[EI_MAG0]
  83   Write8('E');  // e_ident[EI_MAG1]
  84   Write8('L');  // e_ident[EI_MAG2]
  85   Write8('F');  // e_ident[EI_MAG3]
  86
  87   Write8(is64Bit() ? ELF::ELFCLASS64 : ELF::ELFCLASS32); // e_ident[EI_CLASS]
  88
  89   // e_ident[EI_DATA]
  90   Write8(isLittleEndian() ? ELF::ELFDATA2LSB : ELF::ELFDATA2MSB);
  91
  92   Write8(ELF::EV_CURRENT);        // e_ident[EI_VERSION]
  93   // e_ident[EI_OSABI]
  94   switch (TargetObjectWriter->getOSType()) {
  95     case Triple::FreeBSD:  Write8(ELF::ELFOSABI_FREEBSD); break;
  96     case Triple::Linux:    Write8(ELF::ELFOSABI_LINUX); break;
  97     default:               Write8(ELF::ELFOSABI_NONE); break;
  98   }
  99   Write8(0);                  // e_ident[EI_ABIVERSION]
 100
 101   WriteZeros(ELF::EI_NIDENT - ELF::EI_PAD);
 102
 103   Write16(ELF::ET_REL);             // e_type
 104
 105   Write16(TargetObjectWriter->getEMachine()); // e_machine = target
 106
 107   Write32(ELF::EV_CURRENT);         // e_version
 108   WriteWord(0);                    // e_entry, no entry point in .o file
 109   WriteWord(0);                    // e_phoff, no program header for .o
 110   WriteWord(SectionDataSize + (is64Bit() ? sizeof(ELF::Elf64_Ehdr) :
 111             sizeof(ELF::Elf32_Ehdr)));  // e_shoff = sec hdr table off in bytes
 112
 113   // e_flags = whatever the target wants
 114   WriteEFlags();
 115
 116   // e_ehsize = ELF header size
 117   Write16(is64Bit() ? sizeof(ELF::Elf64_Ehdr) : sizeof(ELF::Elf32_Ehdr));
 118
 119   Write16(0);                  // e_phentsize = prog header entry size
 120   Write16(0);                  // e_phnum = # prog header entries = 0
 121
 122   // e_shentsize = Section header entry size
 123   Write16(is64Bit() ? sizeof(ELF::Elf64_Shdr) : sizeof(ELF::Elf32_Shdr));
 124
 125   // e_shnum     = # of section header ents
 126   if (NumberOfSections >= ELF::SHN_LORESERVE)
 127     Write16(0);
 128   else
 129     Write16(NumberOfSections);
 130
 131   // e_shstrndx  = Section # of '.shstrtab'
 132   if (NumberOfSections >= ELF::SHN_LORESERVE)
 133     Write16(ELF::SHN_XINDEX);
 134   else
 135     Write16(ShstrtabIndex);
 136 }
 137
 138 void ELFObjectWriter::WriteSymbolEntry(MCDataFragment *SymtabF,
 139                                        MCDataFragment *ShndxF,
 140                                        uint64_t name,
 141                                        uint8_t info, uint64_t value,
 142                                        uint64_t size, uint8_t other,
 143                                        uint32_t shndx,
 144                                        bool Reserved) {
 145   if (ShndxF) {
 146     if (shndx >= ELF::SHN_LORESERVE && !Reserved)
 147       String32(*ShndxF, shndx);
 148     else
 149       String32(*ShndxF, 0);
 150   }
 151
 152   uint16_t Index = (shndx >= ELF::SHN_LORESERVE && !Reserved) ?
 153     uint16_t(ELF::SHN_XINDEX) : shndx;
 154
 155   if (is64Bit()) {
 156     String32(*SymtabF, name);  // st_name
 157     String8(*SymtabF, info);   // st_info
 158     String8(*SymtabF, other);  // st_other
 159     String16(*SymtabF, Index); // st_shndx
 160     String64(*SymtabF, value); // st_value
 161     String64(*SymtabF, size);  // st_size
 162   } else {
 163     String32(*SymtabF, name);  // st_name
 164     String32(*SymtabF, value); // st_value
 165     String32(*SymtabF, size);  // st_size
 166     String8(*SymtabF, info);   // st_info
 167     String8(*SymtabF, other);  // st_other
 168     String16(*SymtabF, Index); // st_shndx
 169   }
 170 }
 171
 172 uint64_t ELFObjectWriter::SymbolValue(MCSymbolData &Data,
 173                                       const MCAsmLayout &Layout) {
 174   if (Data.isCommon() && Data.isExternal())
 175     return Data.getCommonAlignment();
 176
 177   const MCSymbol &Symbol = Data.getSymbol();
 178
 179   if (Symbol.isAbsolute() && Symbol.isVariable()) {
 180     if (const MCExpr *Value = Symbol.getVariableValue()) {
 181       int64_t IntValue;
 182       if (Value->EvaluateAsAbsolute(IntValue, Layout))
 183         return (uint64_t)IntValue;
 184     }
 185   }
 186
 187   if (!Symbol.isInSection())
 188     return 0;
 189
 190
 191   if (Data.getFragment()) {
 192     if (Data.getFlags() & ELF_Other_ThumbFunc)
 193       return Layout.getSymbolOffset(&Data)+1;
 194     else
 195       return Layout.getSymbolOffset(&Data);
 196   }
 197
 198   return 0;
 199 }
 200
 201 void ELFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
 202                                                const MCAsmLayout &Layout) {
 203   // The presence of symbol versions causes undefined symbols and
 204   // versions declared with @@@ to be renamed.
 205
 206   for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
 207          ie = Asm.symbol_end(); it != ie; ++it) {
 208     const MCSymbol &Alias = it->getSymbol();
 209     const MCSymbol &Symbol = Alias.AliasedSymbol();
 210     MCSymbolData &SD = Asm.getSymbolData(Symbol);
 211
 212     // Not an alias.
 213     if (&Symbol == &Alias)
 214       continue;
 215
 216     StringRef AliasName = Alias.getName();
 217     size_t Pos = AliasName.find('@');
 218     if (Pos == StringRef::npos)
 219       continue;
 220
 221     // Aliases defined with .symvar copy the binding from the symbol they alias.
 222     // This is the first place we are able to copy this information.
 223     it->setExternal(SD.isExternal());
 224     MCELF::SetBinding(*it, MCELF::GetBinding(SD));
 225
 226     StringRef Rest = AliasName.substr(Pos);
 227     if (!Symbol.isUndefined() && !Rest.startswith("@@@"))
 228       continue;
 229
 230     // FIXME: produce a better error message.
 231     if (Symbol.isUndefined() && Rest.startswith("@@") &&
 232         !Rest.startswith("@@@"))
 233       report_fatal_error("A @@ version cannot be undefined");
 234
 235     Renames.insert(std::make_pair(&Symbol, &Alias));
 236   }
 237 }
 238
 239 void ELFObjectWriter::WriteSymbol(MCDataFragment *SymtabF,
 240                                   MCDataFragment *ShndxF,
 241                                   ELFSymbolData &MSD,
 242                                   const MCAsmLayout &Layout) {
 243   MCSymbolData &OrigData = *MSD.SymbolData;
 244   MCSymbolData &Data =
 245     Layout.getAssembler().getSymbolData(OrigData.getSymbol().AliasedSymbol());
 246
 247   bool IsReserved = Data.isCommon() || Data.getSymbol().isAbsolute() ||
 248     Data.getSymbol().isVariable();
 249
 250   uint8_t Binding = MCELF::GetBinding(OrigData);
 251   uint8_t Visibility = MCELF::GetVisibility(OrigData);
 252   uint8_t Type = MCELF::GetType(Data);
 253
 254   uint8_t Info = (Binding << ELF_STB_Shift) | (Type << ELF_STT_Shift);
 255   uint8_t Other = Visibility;
 256
 257   uint64_t Value = SymbolValue(Data, Layout);
 258   uint64_t Size = 0;
 259
 260   assert(!(Data.isCommon() && !Data.isExternal()));
 261
 262   const MCExpr *ESize = Data.getSize();
 263   if (ESize) {
 264     int64_t Res;
 265     if (!ESize->EvaluateAsAbsolute(Res, Layout))
 266       report_fatal_error("Size expression must be absolute.");
 267     Size = Res;
 268   }
 269
 270   // Write out the symbol table entry
 271   WriteSymbolEntry(SymtabF, ShndxF, MSD.StringIndex, Info, Value,
 272                    Size, Other, MSD.SectionIndex, IsReserved);
 273 }
 274
 275 void ELFObjectWriter::WriteSymbolTable(MCDataFragment *SymtabF,
 276                                        MCDataFragment *ShndxF,
 277                                        const MCAssembler &Asm,
 278                                        const MCAsmLayout &Layout,
 279                                      const SectionIndexMapTy &SectionIndexMap) {
 280   // The string table must be emitted first because we need the index
 281   // into the string table for all the symbol names.
 282   assert(StringTable.size() && "Missing string table");
 283
 284   // FIXME: Make sure the start of the symbol table is aligned.
 285
 286   // The first entry is the undefined symbol entry.
 287   WriteSymbolEntry(SymtabF, ShndxF, 0, 0, 0, 0, 0, 0, false);
 288
 289   // Write the symbol table entries.
 290   LastLocalSymbolIndex = LocalSymbolData.size() + 1;
 291   for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i) {
 292     ELFSymbolData &MSD = LocalSymbolData[i];
 293     WriteSymbol(SymtabF, ShndxF, MSD, Layout);
 294   }
 295
 296   // Write out a symbol table entry for each regular section.
 297   for (MCAssembler::const_iterator i = Asm.begin(), e = Asm.end(); i != e;
 298        ++i) {
 299     const MCSectionELF &Section =
 300       static_cast<const MCSectionELF&>(i->getSection());
 301     if (Section.getType() == ELF::SHT_RELA ||
 302         Section.getType() == ELF::SHT_REL ||
 303         Section.getType() == ELF::SHT_STRTAB ||
 304         Section.getType() == ELF::SHT_SYMTAB)
 305       continue;
 306     WriteSymbolEntry(SymtabF, ShndxF, 0, ELF::STT_SECTION, 0, 0,
 307                      ELF::STV_DEFAULT, SectionIndexMap.lookup(&Section), false);
 308     LastLocalSymbolIndex++;
 309   }
 310
 311   for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i) {
 312     ELFSymbolData &MSD = ExternalSymbolData[i];
 313     MCSymbolData &Data = *MSD.SymbolData;
 314     assert(((Data.getFlags() & ELF_STB_Global) ||
 315             (Data.getFlags() & ELF_STB_Weak)) &&
 316            "External symbol requires STB_GLOBAL or STB_WEAK flag");
 317     WriteSymbol(SymtabF, ShndxF, MSD, Layout);
 318     if (MCELF::GetBinding(Data) == ELF::STB_LOCAL)
 319       LastLocalSymbolIndex++;
 320   }
 321
 322   for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i) {
 323     ELFSymbolData &MSD = UndefinedSymbolData[i];
 324     MCSymbolData &Data = *MSD.SymbolData;
 325     WriteSymbol(SymtabF, ShndxF, MSD, Layout);
 326     if (MCELF::GetBinding(Data) == ELF::STB_LOCAL)
 327       LastLocalSymbolIndex++;
 328   }
 329 }
 330
 331 const MCSymbol *ELFObjectWriter::SymbolToReloc(const MCAssembler &Asm,
 332                                                const MCValue &Target,
 333                                                const MCFragment &F,
 334                                                const MCFixup &Fixup,
 335                                                bool IsPCRel) const {
 336   const MCSymbol &Symbol = Target.getSymA()->getSymbol();
 337   const MCSymbol &ASymbol = Symbol.AliasedSymbol();
 338   const MCSymbol *Renamed = Renames.lookup(&Symbol);
 339   const MCSymbolData &SD = Asm.getSymbolData(Symbol);
 340
 341   if (ASymbol.isUndefined()) {
 342     if (Renamed)
 343       return Renamed;
 344     return &ASymbol;
 345   }
 346
 347   if (SD.isExternal()) {
 348     if (Renamed)
 349       return Renamed;
 350     return &Symbol;
 351   }
 352
 353   const MCSectionELF &Section =
 354     static_cast<const MCSectionELF&>(ASymbol.getSection());
 355   const SectionKind secKind = Section.getKind();
 356
 357   if (secKind.isBSS())
 358     return ExplicitRelSym(Asm, Target, F, Fixup, IsPCRel);
 359
 360   if (secKind.isThreadLocal()) {
 361     if (Renamed)
 362       return Renamed;
 363     return &Symbol;
 364   }
 365
 366   MCSymbolRefExpr::VariantKind Kind = Target.getSymA()->getKind();
 367   const MCSectionELF &Sec2 =
 368     static_cast<const MCSectionELF&>(F.getParent()->getSection());
 369
 370   if (&Sec2 != &Section &&
 371       (Kind == MCSymbolRefExpr::VK_PLT ||
 372        Kind == MCSymbolRefExpr::VK_GOTPCREL ||
 373        Kind == MCSymbolRefExpr::VK_GOTOFF)) {
 374     if (Renamed)
 375       return Renamed;
 376     return &Symbol;
 377   }
 378
 379   if (Section.getFlags() & ELF::SHF_MERGE) {
 380     if (Target.getConstant() == 0)
 381       return ExplicitRelSym(Asm, Target, F, Fixup, IsPCRel);
 382     if (Renamed)
 383       return Renamed;
 384     return &Symbol;
 385   }
 386
 387   return ExplicitRelSym(Asm, Target, F, Fixup, IsPCRel);
 388
 389 }
 390
 391
 392 void ELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
 393                                        const MCAsmLayout &Layout,
 394                                        const MCFragment *Fragment,
 395                                        const MCFixup &Fixup,
 396                                        MCValue Target,
 397                                        uint64_t &FixedValue) {
 398   int64_t Addend = 0;
 399   int Index = 0;
 400   int64_t Value = Target.getConstant();
 401   const MCSymbol *RelocSymbol = NULL;
 402
 403   bool IsPCRel = isFixupKindPCRel(Asm, Fixup.getKind());
 404   if (!Target.isAbsolute()) {
 405     const MCSymbol &Symbol = Target.getSymA()->getSymbol();
 406     const MCSymbol &ASymbol = Symbol.AliasedSymbol();
 407     RelocSymbol = SymbolToReloc(Asm, Target, *Fragment, Fixup, IsPCRel);
 408
 409     if (const MCSymbolRefExpr *RefB = Target.getSymB()) {
 410       const MCSymbol &SymbolB = RefB->getSymbol();
 411       MCSymbolData &SDB = Asm.getSymbolData(SymbolB);
 412       IsPCRel = true;
 413
 414       // Offset of the symbol in the section
 415       int64_t a = Layout.getSymbolOffset(&SDB);
 416
 417       // Ofeset of the relocation in the section
 418       int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
 419       Value += b - a;
 420     }
 421
 422     if (!RelocSymbol) {
 423       MCSymbolData &SD = Asm.getSymbolData(ASymbol);
 424       MCFragment *F = SD.getFragment();
 425
 426       Index = F->getParent()->getOrdinal() + 1;
 427
 428       // Offset of the symbol in the section
 429       Value += Layout.getSymbolOffset(&SD);
 430     } else {
 431       if (Asm.getSymbolData(Symbol).getFlags() & ELF_Other_Weakref)
 432         WeakrefUsedInReloc.insert(RelocSymbol);
 433       else
 434         UsedInReloc.insert(RelocSymbol);
 435       Index = -1;
 436     }
 437     Addend = Value;
 438     // Compensate for the addend on i386.
 439     if (is64Bit())
 440       Value = 0;
 441   }
 442
 443   FixedValue = Value;
 444   unsigned Type = GetRelocType(Target, Fixup, IsPCRel,
 445                                (RelocSymbol != 0), Addend);
 446
 447   uint64_t RelocOffset = Layout.getFragmentOffset(Fragment) +
 448     Fixup.getOffset();
 449
 450   if (!hasRelocationAddend())
 451     Addend = 0;
 452   ELFRelocationEntry ERE(RelocOffset, Index, Type, RelocSymbol, Addend);
 453   Relocations[Fragment->getParent()].push_back(ERE);
 454 }
 455
 456
 457 uint64_t
 458 ELFObjectWriter::getSymbolIndexInSymbolTable(const MCAssembler &Asm,
 459                                              const MCSymbol *S) {
 460   MCSymbolData &SD = Asm.getSymbolData(*S);
 461   return SD.getIndex();
 462 }
 463
 464 bool ELFObjectWriter::isInSymtab(const MCAssembler &Asm,
 465                                  const MCSymbolData &Data,
 466                                  bool Used, bool Renamed) {
 467   if (Data.getFlags() & ELF_Other_Weakref)
 468     return false;
 469
 470   if (Used)
 471     return true;
 472
 473   if (Renamed)
 474     return false;
 475
 476   const MCSymbol &Symbol = Data.getSymbol();
 477
 478   if (Symbol.getName() == "_GLOBAL_OFFSET_TABLE_")
 479     return true;
 480
 481   const MCSymbol &A = Symbol.AliasedSymbol();
 482   if (Symbol.isVariable() && !A.isVariable() && A.isUndefined())
 483     return false;
 484
 485   bool IsGlobal = MCELF::GetBinding(Data) == ELF::STB_GLOBAL;
 486   if (!Symbol.isVariable() && Symbol.isUndefined() && !IsGlobal)
 487     return false;
 488
 489   if (!Asm.isSymbolLinkerVisible(Symbol) && !Symbol.isUndefined())
 490     return false;
 491
 492   if (Symbol.isTemporary())
 493     return false;
 494
 495   return true;
 496 }
 497
 498 bool ELFObjectWriter::isLocal(const MCSymbolData &Data, bool isSignature,
 499                               bool isUsedInReloc) {
 500   if (Data.isExternal())
 501     return false;
 502
 503   const MCSymbol &Symbol = Data.getSymbol();
 504   const MCSymbol &RefSymbol = Symbol.AliasedSymbol();
 505
 506   if (RefSymbol.isUndefined() && !RefSymbol.isVariable()) {
 507     if (isSignature && !isUsedInReloc)
 508       return true;
 509
 510     return false;
 511   }
 512
 513   return true;
 514 }
 515
 516 void ELFObjectWriter::ComputeIndexMap(MCAssembler &Asm,
 517                                       SectionIndexMapTy &SectionIndexMap,
 518                                       const RelMapTy &RelMap) {
 519   unsigned Index = 1;
 520   for (MCAssembler::iterator it = Asm.begin(),
 521          ie = Asm.end(); it != ie; ++it) {
 522     const MCSectionELF &Section =
 523       static_cast<const MCSectionELF &>(it->getSection());
 524     if (Section.getType() != ELF::SHT_GROUP)
 525       continue;
 526     SectionIndexMap[&Section] = Index++;
 527   }
 528
 529   for (MCAssembler::iterator it = Asm.begin(),
 530          ie = Asm.end(); it != ie; ++it) {
 531     const MCSectionELF &Section =
 532       static_cast<const MCSectionELF &>(it->getSection());
 533     if (Section.getType() == ELF::SHT_GROUP ||
 534         Section.getType() == ELF::SHT_REL ||
 535         Section.getType() == ELF::SHT_RELA)
 536       continue;
 537     SectionIndexMap[&Section] = Index++;
 538     const MCSectionELF *RelSection = RelMap.lookup(&Section);
 539     if (RelSection)
 540       SectionIndexMap[RelSection] = Index++;
 541   }
 542 }
 543
 544 void ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm,
 545                                       const SectionIndexMapTy &SectionIndexMap,
 546                                          RevGroupMapTy RevGroupMap,
 547                                          unsigned NumRegularSections) {
 548   // FIXME: Is this the correct place to do this?
 549   // FIXME: Why is an undefined reference to _GLOBAL_OFFSET_TABLE_ needed?
 550   if (NeedsGOT) {
 551     llvm::StringRef Name = "_GLOBAL_OFFSET_TABLE_";
 552     MCSymbol *Sym = Asm.getContext().GetOrCreateSymbol(Name);
 553     MCSymbolData &Data = Asm.getOrCreateSymbolData(*Sym);
 554     Data.setExternal(true);
 555     MCELF::SetBinding(Data, ELF::STB_GLOBAL);
 556   }
 557
 558   // Index 0 is always the empty string.
 559   StringMap<uint64_t> StringIndexMap;
 560   StringTable += '\x00';
 561
 562   // FIXME: We could optimize suffixes in strtab in the same way we
 563   // optimize them in shstrtab.
 564
 565   // Add the data for the symbols.
 566   for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
 567          ie = Asm.symbol_end(); it != ie; ++it) {
 568     const MCSymbol &Symbol = it->getSymbol();
 569
 570     bool Used = UsedInReloc.count(&Symbol);
 571     bool WeakrefUsed = WeakrefUsedInReloc.count(&Symbol);
 572     bool isSignature = RevGroupMap.count(&Symbol);
 573
 574     if (!isInSymtab(Asm, *it,
 575                     Used || WeakrefUsed || isSignature,
 576                     Renames.count(&Symbol)))
 577       continue;
 578
 579     ELFSymbolData MSD;
 580     MSD.SymbolData = it;
 581     const MCSymbol &RefSymbol = Symbol.AliasedSymbol();
 582
 583     // Undefined symbols are global, but this is the first place we
 584     // are able to set it.
 585     bool Local = isLocal(*it, isSignature, Used);
 586     if (!Local && MCELF::GetBinding(*it) == ELF::STB_LOCAL) {
 587       MCSymbolData &SD = Asm.getSymbolData(RefSymbol);
 588       MCELF::SetBinding(*it, ELF::STB_GLOBAL);
 589       MCELF::SetBinding(SD, ELF::STB_GLOBAL);
 590     }
 591
 592     if (RefSymbol.isUndefined() && !Used && WeakrefUsed)
 593       MCELF::SetBinding(*it, ELF::STB_WEAK);
 594
 595     if (it->isCommon()) {
 596       assert(!Local);
 597       MSD.SectionIndex = ELF::SHN_COMMON;
 598     } else if (Symbol.isAbsolute() || RefSymbol.isVariable()) {
 599       MSD.SectionIndex = ELF::SHN_ABS;
 600     } else if (RefSymbol.isUndefined()) {
 601       if (isSignature && !Used)
 602         MSD.SectionIndex = SectionIndexMap.lookup(RevGroupMap[&Symbol]);
 603       else
 604         MSD.SectionIndex = ELF::SHN_UNDEF;
 605     } else {
 606       const MCSectionELF &Section =
 607         static_cast<const MCSectionELF&>(RefSymbol.getSection());
 608       MSD.SectionIndex = SectionIndexMap.lookup(&Section);
 609       if (MSD.SectionIndex >= ELF::SHN_LORESERVE)
 610         NeedsSymtabShndx = true;
 611       assert(MSD.SectionIndex && "Invalid section index!");
 612     }
 613
 614     // The @@@ in symbol version is replaced with @ in undefined symbols and
 615     // @@ in defined ones.
 616     StringRef Name = Symbol.getName();
 617     SmallString<32> Buf;
 618
 619     size_t Pos = Name.find("@@@");
 620     if (Pos != StringRef::npos) {
 621       Buf += Name.substr(0, Pos);
 622       unsigned Skip = MSD.SectionIndex == ELF::SHN_UNDEF ? 2 : 1;
 623       Buf += Name.substr(Pos + Skip);
 624       Name = Buf;
 625     }
 626
 627     uint64_t &Entry = StringIndexMap[Name];
 628     if (!Entry) {
 629       Entry = StringTable.size();
 630       StringTable += Name;
 631       StringTable += '\x00';
 632     }
 633     MSD.StringIndex = Entry;
 634     if (MSD.SectionIndex == ELF::SHN_UNDEF)
 635       UndefinedSymbolData.push_back(MSD);
 636     else if (Local)
 637       LocalSymbolData.push_back(MSD);
 638     else
 639       ExternalSymbolData.push_back(MSD);
 640   }
 641
 642   // Symbols are required to be in lexicographic order.
 643   array_pod_sort(LocalSymbolData.begin(), LocalSymbolData.end());
 644   array_pod_sort(ExternalSymbolData.begin(), ExternalSymbolData.end());
 645   array_pod_sort(UndefinedSymbolData.begin(), UndefinedSymbolData.end());
 646
 647   // Set the symbol indices. Local symbols must come before all other
 648   // symbols with non-local bindings.
 649   unsigned Index = 1;
 650   for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i)
 651     LocalSymbolData[i].SymbolData->setIndex(Index++);
 652
 653   Index += NumRegularSections;
 654
 655   for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i)
 656     ExternalSymbolData[i].SymbolData->setIndex(Index++);
 657   for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i)
 658     UndefinedSymbolData[i].SymbolData->setIndex(Index++);
 659 }
 660
 661 void ELFObjectWriter::CreateRelocationSections(MCAssembler &Asm,
 662                                                MCAsmLayout &Layout,
 663                                                RelMapTy &RelMap) {
 664   for (MCAssembler::const_iterator it = Asm.begin(),
 665          ie = Asm.end(); it != ie; ++it) {
 666     const MCSectionData &SD = *it;
 667     if (Relocations[&SD].empty())
 668       continue;
 669
 670     MCContext &Ctx = Asm.getContext();
 671     const MCSectionELF &Section =
 672       static_cast<const MCSectionELF&>(SD.getSection());
 673
 674     const StringRef SectionName = Section.getSectionName();
 675     std::string RelaSectionName = hasRelocationAddend() ? ".rela" : ".rel";
 676     RelaSectionName += SectionName;
 677
 678     unsigned EntrySize;
 679     if (hasRelocationAddend())
 680       EntrySize = is64Bit() ? sizeof(ELF::Elf64_Rela) : sizeof(ELF::Elf32_Rela);
 681     else
 682       EntrySize = is64Bit() ? sizeof(ELF::Elf64_Rel) : sizeof(ELF::Elf32_Rel);
 683
 684     const MCSectionELF *RelaSection =
 685       Ctx.getELFSection(RelaSectionName, hasRelocationAddend() ?
 686                         ELF::SHT_RELA : ELF::SHT_REL, 0,
 687                         SectionKind::getReadOnly(),
 688                         EntrySize, "");
 689     RelMap[&Section] = RelaSection;
 690     Asm.getOrCreateSectionData(*RelaSection);
 691   }
 692 }
 693
 694 void ELFObjectWriter::WriteRelocations(MCAssembler &Asm, MCAsmLayout &Layout,
 695                                        const RelMapTy &RelMap) {
 696   for (MCAssembler::const_iterator it = Asm.begin(),
 697          ie = Asm.end(); it != ie; ++it) {
 698     const MCSectionData &SD = *it;
 699     const MCSectionELF &Section =
 700       static_cast<const MCSectionELF&>(SD.getSection());
 701
 702     const MCSectionELF *RelaSection = RelMap.lookup(&Section);
 703     if (!RelaSection)
 704       continue;
 705     MCSectionData &RelaSD = Asm.getOrCreateSectionData(*RelaSection);
 706     RelaSD.setAlignment(is64Bit() ? 8 : 4);
 707
 708     MCDataFragment *F = new MCDataFragment(&RelaSD);
 709     WriteRelocationsFragment(Asm, F, &*it);
 710   }
 711 }
 712
 713 void ELFObjectWriter::WriteSecHdrEntry(uint32_t Name, uint32_t Type,
 714                                        uint64_t Flags, uint64_t Address,
 715                                        uint64_t Offset, uint64_t Size,
 716                                        uint32_t Link, uint32_t Info,
 717                                        uint64_t Alignment,
 718                                        uint64_t EntrySize) {
 719   Write32(Name);        // sh_name: index into string table
 720   Write32(Type);        // sh_type
 721   WriteWord(Flags);     // sh_flags
 722   WriteWord(Address);   // sh_addr
 723   WriteWord(Offset);    // sh_offset
 724   WriteWord(Size);      // sh_size
 725   Write32(Link);        // sh_link
 726   Write32(Info);        // sh_info
 727   WriteWord(Alignment); // sh_addralign
 728   WriteWord(EntrySize); // sh_entsize
 729 }
 730
 731 void ELFObjectWriter::WriteRelocationsFragment(const MCAssembler &Asm,
 732                                                MCDataFragment *F,
 733                                                const MCSectionData *SD) {
 734   std::vector<ELFRelocationEntry> &Relocs = Relocations[SD];
 735   // sort by the r_offset just like gnu as does
 736   array_pod_sort(Relocs.begin(), Relocs.end());
 737
 738   for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
 739     ELFRelocationEntry entry = Relocs[e - i - 1];
 740
 741     if (!entry.Index)
 742       ;
 743     else if (entry.Index < 0)
 744       entry.Index = getSymbolIndexInSymbolTable(Asm, entry.Symbol);
 745     else
 746       entry.Index += LocalSymbolData.size();
 747     if (is64Bit()) {
 748       String64(*F, entry.r_offset);
 749
 750       struct ELF::Elf64_Rela ERE64;
 751       ERE64.setSymbolAndType(entry.Index, entry.Type);
 752       String64(*F, ERE64.r_info);
 753
 754       if (hasRelocationAddend())
 755         String64(*F, entry.r_addend);
 756     } else {
 757       String32(*F, entry.r_offset);
 758
 759       struct ELF::Elf32_Rela ERE32;
 760       ERE32.setSymbolAndType(entry.Index, entry.Type);
 761       String32(*F, ERE32.r_info);
 762
 763       if (hasRelocationAddend())
 764         String32(*F, entry.r_addend);
 765     }
 766   }
 767 }
 768
 769 static int compareBySuffix(const void *a, const void *b) {
 770   const MCSectionELF *secA = *static_cast<const MCSectionELF* const *>(a);
 771   const MCSectionELF *secB = *static_cast<const MCSectionELF* const *>(b);
 772   const StringRef &NameA = secA->getSectionName();
 773   const StringRef &NameB = secB->getSectionName();
 774   const unsigned sizeA = NameA.size();
 775   const unsigned sizeB = NameB.size();
 776   const unsigned len = std::min(sizeA, sizeB);
 777   for (unsigned int i = 0; i < len; ++i) {
 778     char ca = NameA[sizeA - i - 1];
 779     char cb = NameB[sizeB - i - 1];
 780     if (ca != cb)
 781       return cb - ca;
 782   }
 783
 784   return sizeB - sizeA;
 785 }
 786
 787 void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm,
 788                                              MCAsmLayout &Layout,
 789                                              SectionIndexMapTy &SectionIndexMap,
 790                                              const RelMapTy &RelMap) {
 791   MCContext &Ctx = Asm.getContext();
 792   MCDataFragment *F;
 793
 794   unsigned EntrySize = is64Bit() ? ELF::SYMENTRY_SIZE64 : ELF::SYMENTRY_SIZE32;
 795
 796   // We construct .shstrtab, .symtab and .strtab in this order to match gnu as.
 797   const MCSectionELF *ShstrtabSection =
 798     Ctx.getELFSection(".shstrtab", ELF::SHT_STRTAB, 0,
 799                       SectionKind::getReadOnly());
 800   MCSectionData &ShstrtabSD = Asm.getOrCreateSectionData(*ShstrtabSection);
 801   ShstrtabSD.setAlignment(1);
 802
 803   const MCSectionELF *SymtabSection =
 804     Ctx.getELFSection(".symtab", ELF::SHT_SYMTAB, 0,
 805                       SectionKind::getReadOnly(),
 806                       EntrySize, "");
 807   MCSectionData &SymtabSD = Asm.getOrCreateSectionData(*SymtabSection);
 808   SymtabSD.setAlignment(is64Bit() ? 8 : 4);
 809
 810   MCSectionData *SymtabShndxSD = NULL;
 811
 812   if (NeedsSymtabShndx) {
 813     const MCSectionELF *SymtabShndxSection =
 814       Ctx.getELFSection(".symtab_shndx", ELF::SHT_SYMTAB_SHNDX, 0,
 815                         SectionKind::getReadOnly(), 4, "");
 816     SymtabShndxSD = &Asm.getOrCreateSectionData(*SymtabShndxSection);
 817     SymtabShndxSD->setAlignment(4);
 818   }
 819
 820   const MCSectionELF *StrtabSection;
 821   StrtabSection = Ctx.getELFSection(".strtab", ELF::SHT_STRTAB, 0,
 822                                     SectionKind::getReadOnly());
 823   MCSectionData &StrtabSD = Asm.getOrCreateSectionData(*StrtabSection);
 824   StrtabSD.setAlignment(1);
 825
 826   ComputeIndexMap(Asm, SectionIndexMap, RelMap);
 827
 828   ShstrtabIndex = SectionIndexMap.lookup(ShstrtabSection);
 829   SymbolTableIndex = SectionIndexMap.lookup(SymtabSection);
 830   StringTableIndex = SectionIndexMap.lookup(StrtabSection);
 831
 832   // Symbol table
 833   F = new MCDataFragment(&SymtabSD);
 834   MCDataFragment *ShndxF = NULL;
 835   if (NeedsSymtabShndx) {
 836     ShndxF = new MCDataFragment(SymtabShndxSD);
 837   }
 838   WriteSymbolTable(F, ShndxF, Asm, Layout, SectionIndexMap);
 839
 840   F = new MCDataFragment(&StrtabSD);
 841   F->getContents().append(StringTable.begin(), StringTable.end());
 842
 843   F = new MCDataFragment(&ShstrtabSD);
 844
 845   std::vector<const MCSectionELF*> Sections;
 846   for (MCAssembler::const_iterator it = Asm.begin(),
 847          ie = Asm.end(); it != ie; ++it) {
 848     const MCSectionELF &Section =
 849       static_cast<const MCSectionELF&>(it->getSection());
 850     Sections.push_back(&Section);
 851   }
 852   array_pod_sort(Sections.begin(), Sections.end(), compareBySuffix);
 853
 854   // Section header string table.
 855   //
 856   // The first entry of a string table holds a null character so skip
 857   // section 0.
 858   uint64_t Index = 1;
 859   F->getContents() += '\x00';
 860
 861   for (unsigned int I = 0, E = Sections.size(); I != E; ++I) {
 862     const MCSectionELF &Section = *Sections[I];
 863
 864     StringRef Name = Section.getSectionName();
 865     if (I != 0) {
 866       StringRef PreviousName = Sections[I - 1]->getSectionName();
 867       if (PreviousName.endswith(Name)) {
 868         SectionStringTableIndex[&Section] = Index - Name.size() - 1;
 869         continue;
 870       }
 871     }
 872     // Remember the index into the string table so we can write it
 873     // into the sh_name field of the section header table.
 874     SectionStringTableIndex[&Section] = Index;
 875
 876     Index += Name.size() + 1;
 877     F->getContents() += Name;
 878     F->getContents() += '\x00';
 879   }
 880 }
 881
 882 void ELFObjectWriter::CreateIndexedSections(MCAssembler &Asm,
 883                                             MCAsmLayout &Layout,
 884                                             GroupMapTy &GroupMap,
 885                                             RevGroupMapTy &RevGroupMap,
 886                                             SectionIndexMapTy &SectionIndexMap,
 887                                             const RelMapTy &RelMap) {
 888   // Create the .note.GNU-stack section if needed.
 889   MCContext &Ctx = Asm.getContext();
 890   if (Asm.getNoExecStack()) {
 891     const MCSectionELF *GnuStackSection =
 892       Ctx.getELFSection(".note.GNU-stack", ELF::SHT_PROGBITS, 0,
 893                         SectionKind::getReadOnly());
 894     Asm.getOrCreateSectionData(*GnuStackSection);
 895   }
 896
 897   // Build the groups
 898   for (MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end();
 899        it != ie; ++it) {
 900     const MCSectionELF &Section =
 901       static_cast<const MCSectionELF&>(it->getSection());
 902     if (!(Section.getFlags() & ELF::SHF_GROUP))
 903       continue;
 904
 905     const MCSymbol *SignatureSymbol = Section.getGroup();
 906     Asm.getOrCreateSymbolData(*SignatureSymbol);
 907     const MCSectionELF *&Group = RevGroupMap[SignatureSymbol];
 908     if (!Group) {
 909       Group = Ctx.CreateELFGroupSection();
 910       MCSectionData &Data = Asm.getOrCreateSectionData(*Group);
 911       Data.setAlignment(4);
 912       MCDataFragment *F = new MCDataFragment(&Data);
 913       String32(*F, ELF::GRP_COMDAT);
 914     }
 915     GroupMap[Group] = SignatureSymbol;
 916   }
 917
 918   ComputeIndexMap(Asm, SectionIndexMap, RelMap);
 919
 920   // Add sections to the groups
 921   for (MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end();
 922        it != ie; ++it) {
 923     const MCSectionELF &Section =
 924       static_cast<const MCSectionELF&>(it->getSection());
 925     if (!(Section.getFlags() & ELF::SHF_GROUP))
 926       continue;
 927     const MCSectionELF *Group = RevGroupMap[Section.getGroup()];
 928     MCSectionData &Data = Asm.getOrCreateSectionData(*Group);
 929     // FIXME: we could use the previous fragment
 930     MCDataFragment *F = new MCDataFragment(&Data);
 931     unsigned Index = SectionIndexMap.lookup(&Section);
 932     String32(*F, Index);
 933   }
 934 }
 935
 936 void ELFObjectWriter::WriteSection(MCAssembler &Asm,
 937                                    const SectionIndexMapTy &SectionIndexMap,
 938                                    uint32_t GroupSymbolIndex,
 939                                    uint64_t Offset, uint64_t Size,
 940                                    uint64_t Alignment,
 941                                    const MCSectionELF &Section) {
 942   uint64_t sh_link = 0;
 943   uint64_t sh_info = 0;
 944
 945   switch(Section.getType()) {
 946   case ELF::SHT_DYNAMIC:
 947     sh_link = SectionStringTableIndex[&Section];
 948     sh_info = 0;
 949     break;
 950
 951   case ELF::SHT_REL:
 952   case ELF::SHT_RELA: {
 953     const MCSectionELF *SymtabSection;
 954     const MCSectionELF *InfoSection;
 955     SymtabSection = Asm.getContext().getELFSection(".symtab", ELF::SHT_SYMTAB,
 956                                                    0,
 957                                                    SectionKind::getReadOnly());
 958     sh_link = SectionIndexMap.lookup(SymtabSection);
 959     assert(sh_link && ".symtab not found");
 960
 961     // Remove ".rel" and ".rela" prefixes.
 962     unsigned SecNameLen = (Section.getType() == ELF::SHT_REL) ? 4 : 5;
 963     StringRef SectionName = Section.getSectionName().substr(SecNameLen);
 964
 965     InfoSection = Asm.getContext().getELFSection(SectionName,
 966                                                  ELF::SHT_PROGBITS, 0,
 967                                                  SectionKind::getReadOnly());
 968     sh_info = SectionIndexMap.lookup(InfoSection);
 969     break;
 970   }
 971
 972   case ELF::SHT_SYMTAB:
 973   case ELF::SHT_DYNSYM:
 974     sh_link = StringTableIndex;
 975     sh_info = LastLocalSymbolIndex;
 976     break;
 977
 978   case ELF::SHT_SYMTAB_SHNDX:
 979     sh_link = SymbolTableIndex;
 980     break;
 981
 982   case ELF::SHT_PROGBITS:
 983   case ELF::SHT_STRTAB:
 984   case ELF::SHT_NOBITS:
 985   case ELF::SHT_NOTE:
 986   case ELF::SHT_NULL:
 987   case ELF::SHT_ARM_ATTRIBUTES:
 988   case ELF::SHT_INIT_ARRAY:
 989   case ELF::SHT_FINI_ARRAY:
 990   case ELF::SHT_PREINIT_ARRAY:
 991   case ELF::SHT_X86_64_UNWIND:
 992     // Nothing to do.
 993     break;
 994
 995   case ELF::SHT_GROUP: {
 996     sh_link = SymbolTableIndex;
 997     sh_info = GroupSymbolIndex;
 998     break;
 999   }
1000
1001   default:
1002     assert(0 && "FIXME: sh_type value not supported!");
1003     break;
1004   }
1005
1006   WriteSecHdrEntry(SectionStringTableIndex[&Section], Section.getType(),
1007                    Section.getFlags(), 0, Offset, Size, sh_link, sh_info,
1008                    Alignment, Section.getEntrySize());
1009 }
1010
1011 bool ELFObjectWriter::IsELFMetaDataSection(const MCSectionData &SD) {
1012   return SD.getOrdinal() == ~UINT32_C(0) &&
1013     !SD.getSection().isVirtualSection();
1014 }
1015
1016 uint64_t ELFObjectWriter::DataSectionSize(const MCSectionData &SD) {
1017   uint64_t Ret = 0;
1018   for (MCSectionData::const_iterator i = SD.begin(), e = SD.end(); i != e;
1019        ++i) {
1020     const MCFragment &F = *i;
1021     assert(F.getKind() == MCFragment::FT_Data);
1022     Ret += cast<MCDataFragment>(F).getContents().size();
1023   }
1024   return Ret;
1025 }
1026
1027 uint64_t ELFObjectWriter::GetSectionFileSize(const MCAsmLayout &Layout,
1028                                              const MCSectionData &SD) {
1029   if (IsELFMetaDataSection(SD))
1030     return DataSectionSize(SD);
1031   return Layout.getSectionFileSize(&SD);
1032 }
1033
1034 uint64_t ELFObjectWriter::GetSectionAddressSize(const MCAsmLayout &Layout,
1035                                                 const MCSectionData &SD) {
1036   if (IsELFMetaDataSection(SD))
1037     return DataSectionSize(SD);
1038   return Layout.getSectionAddressSize(&SD);
1039 }
1040
1041 void ELFObjectWriter::WriteDataSectionData(MCAssembler &Asm,
1042                                            const MCAsmLayout &Layout,
1043                                            const MCSectionELF &Section) {
1044   uint64_t FileOff = OS.tell();
1045   const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
1046
1047   uint64_t Padding = OffsetToAlignment(FileOff, SD.getAlignment());
1048   WriteZeros(Padding);
1049   FileOff += Padding;
1050
1051   FileOff += GetSectionFileSize(Layout, SD);
1052
1053   if (IsELFMetaDataSection(SD)) {
1054     for (MCSectionData::const_iterator i = SD.begin(), e = SD.end(); i != e;
1055          ++i) {
1056       const MCFragment &F = *i;
1057       assert(F.getKind() == MCFragment::FT_Data);
1058       WriteBytes(cast<MCDataFragment>(F).getContents().str());
1059     }
1060   } else {
1061     Asm.WriteSectionData(&SD, Layout);
1062   }
1063 }
1064
1065 void ELFObjectWriter::WriteSectionHeader(MCAssembler &Asm,
1066                                          const GroupMapTy &GroupMap,
1067                                          const MCAsmLayout &Layout,
1068                                       const SectionIndexMapTy &SectionIndexMap,
1069                                    const SectionOffsetMapTy &SectionOffsetMap) {
1070   const unsigned NumSections = Asm.size() + 1;
1071
1072   std::vector<const MCSectionELF*> Sections;
1073   Sections.resize(NumSections - 1);
1074
1075   for (SectionIndexMapTy::const_iterator i=
1076          SectionIndexMap.begin(), e = SectionIndexMap.end(); i != e; ++i) {
1077     const std::pair<const MCSectionELF*, uint32_t> &p = *i;
1078     Sections[p.second - 1] = p.first;
1079   }
1080
1081   // Null section first.
1082   uint64_t FirstSectionSize =
1083     NumSections >= ELF::SHN_LORESERVE ? NumSections : 0;
1084   uint32_t FirstSectionLink =
1085     ShstrtabIndex >= ELF::SHN_LORESERVE ? ShstrtabIndex : 0;
1086   WriteSecHdrEntry(0, 0, 0, 0, 0, FirstSectionSize, FirstSectionLink, 0, 0, 0);
1087
1088   for (unsigned i = 0; i < NumSections - 1; ++i) {
1089     const MCSectionELF &Section = *Sections[i];
1090     const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
1091     uint32_t GroupSymbolIndex;
1092     if (Section.getType() != ELF::SHT_GROUP)
1093       GroupSymbolIndex = 0;
1094     else
1095       GroupSymbolIndex = getSymbolIndexInSymbolTable(Asm,
1096                                                      GroupMap.lookup(&Section));
1097
1098     uint64_t Size = GetSectionAddressSize(Layout, SD);
1099
1100     WriteSection(Asm, SectionIndexMap, GroupSymbolIndex,
1101                  SectionOffsetMap.lookup(&Section), Size,
1102                  SD.getAlignment(), Section);
1103   }
1104 }
1105
1106 void ELFObjectWriter::ComputeSectionOrder(MCAssembler &Asm,
1107                                   std::vector<const MCSectionELF*> &Sections) {
1108   for (MCAssembler::iterator it = Asm.begin(),
1109          ie = Asm.end(); it != ie; ++it) {
1110     const MCSectionELF &Section =
1111       static_cast<const MCSectionELF &>(it->getSection());
1112     if (Section.getType() == ELF::SHT_GROUP)
1113       Sections.push_back(&Section);
1114   }
1115
1116   for (MCAssembler::iterator it = Asm.begin(),
1117          ie = Asm.end(); it != ie; ++it) {
1118     const MCSectionELF &Section =
1119       static_cast<const MCSectionELF &>(it->getSection());
1120     if (Section.getType() != ELF::SHT_GROUP &&
1121         Section.getType() != ELF::SHT_REL &&
1122         Section.getType() != ELF::SHT_RELA)
1123       Sections.push_back(&Section);
1124   }
1125
1126   for (MCAssembler::iterator it = Asm.begin(),
1127          ie = Asm.end(); it != ie; ++it) {
1128     const MCSectionELF &Section =
1129       static_cast<const MCSectionELF &>(it->getSection());
1130     if (Section.getType() == ELF::SHT_REL ||
1131         Section.getType() == ELF::SHT_RELA)
1132       Sections.push_back(&Section);
1133   }
1134 }
1135
1136 void ELFObjectWriter::WriteObject(MCAssembler &Asm,
1137                                   const MCAsmLayout &Layout) {
1138   GroupMapTy GroupMap;
1139   RevGroupMapTy RevGroupMap;
1140   SectionIndexMapTy SectionIndexMap;
1141
1142   unsigned NumUserSections = Asm.size();
1143
1144   DenseMap<const MCSectionELF*, const MCSectionELF*> RelMap;
1145   CreateRelocationSections(Asm, const_cast<MCAsmLayout&>(Layout), RelMap);
1146
1147   const unsigned NumUserAndRelocSections = Asm.size();
1148   CreateIndexedSections(Asm, const_cast<MCAsmLayout&>(Layout), GroupMap,
1149                         RevGroupMap, SectionIndexMap, RelMap);
1150   const unsigned AllSections = Asm.size();
1151   const unsigned NumIndexedSections = AllSections - NumUserAndRelocSections;
1152
1153   unsigned NumRegularSections = NumUserSections + NumIndexedSections;
1154
1155   // Compute symbol table information.
1156   ComputeSymbolTable(Asm, SectionIndexMap, RevGroupMap, NumRegularSections);
1157
1158
1159   WriteRelocations(Asm, const_cast<MCAsmLayout&>(Layout), RelMap);
1160
1161   CreateMetadataSections(const_cast<MCAssembler&>(Asm),
1162                          const_cast<MCAsmLayout&>(Layout),
1163                          SectionIndexMap,
1164                          RelMap);
1165
1166   uint64_t NaturalAlignment = is64Bit() ? 8 : 4;
1167   uint64_t HeaderSize = is64Bit() ? sizeof(ELF::Elf64_Ehdr) :
1168                                     sizeof(ELF::Elf32_Ehdr);
1169   uint64_t FileOff = HeaderSize;
1170
1171   std::vector<const MCSectionELF*> Sections;
1172   ComputeSectionOrder(Asm, Sections);
1173   unsigned NumSections = Sections.size();
1174   SectionOffsetMapTy SectionOffsetMap;
1175   for (unsigned i = 0; i < NumRegularSections + 1; ++i) {
1176     const MCSectionELF &Section = *Sections[i];
1177     const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
1178
1179     FileOff = RoundUpToAlignment(FileOff, SD.getAlignment());
1180
1181     // Remember the offset into the file for this section.
1182     SectionOffsetMap[&Section] = FileOff;
1183
1184     // Get the size of the section in the output file (including padding).
1185     FileOff += GetSectionFileSize(Layout, SD);
1186   }
1187
1188   FileOff = RoundUpToAlignment(FileOff, NaturalAlignment);
1189
1190   const unsigned SectionHeaderOffset = FileOff - HeaderSize;
1191
1192   uint64_t SectionHeaderEntrySize = is64Bit() ?
1193     sizeof(ELF::Elf64_Shdr) : sizeof(ELF::Elf32_Shdr);
1194   FileOff += (NumSections + 1) * SectionHeaderEntrySize;
1195
1196   for (unsigned i = NumRegularSections + 1; i < NumSections; ++i) {
1197     const MCSectionELF &Section = *Sections[i];
1198     const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
1199
1200     FileOff = RoundUpToAlignment(FileOff, SD.getAlignment());
1201
1202     // Remember the offset into the file for this section.
1203     SectionOffsetMap[&Section] = FileOff;
1204
1205     // Get the size of the section in the output file (including padding).
1206     FileOff += GetSectionFileSize(Layout, SD);
1207   }
1208
1209   // Write out the ELF header ...
1210   WriteHeader(SectionHeaderOffset, NumSections + 1);
1211
1212   // ... then the regular sections ...
1213   // + because of .shstrtab
1214   for (unsigned i = 0; i < NumRegularSections + 1; ++i)
1215     WriteDataSectionData(Asm, Layout, *Sections[i]);
1216
1217   FileOff = OS.tell();
1218   uint64_t Padding = OffsetToAlignment(FileOff, NaturalAlignment);
1219   WriteZeros(Padding);
1220
1221   // ... then the section header table ...
1222   WriteSectionHeader(Asm, GroupMap, Layout, SectionIndexMap,
1223                      SectionOffsetMap);
1224
1225   FileOff = OS.tell();
1226
1227   // ... and then the remainting sections ...
1228   for (unsigned i = NumRegularSections + 1; i < NumSections; ++i)
1229     WriteDataSectionData(Asm, Layout, *Sections[i]);
1230 }
1231
1232 bool
1233 ELFObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
1234                                                       const MCSymbolData &DataA,
1235                                                       const MCFragment &FB,
1236                                                       bool InSet,
1237                                                       bool IsPCRel) const {
1238   if (DataA.getFlags() & ELF_STB_Weak)
1239     return false;
1240   return MCObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(
1241                                                  Asm, DataA, FB,InSet, IsPCRel);
1242 }
1243
1244 MCObjectWriter *llvm::createELFObjectWriter(MCELFObjectTargetWriter *MOTW,
1245                                             raw_ostream &OS,
1246                                             bool IsLittleEndian) {
1247   switch (MOTW->getEMachine()) {
1248     case ELF::EM_386:
1249     case ELF::EM_X86_64:
1250       return new X86ELFObjectWriter(MOTW, OS, IsLittleEndian); break;
1251     case ELF::EM_ARM:
1252       return new ARMELFObjectWriter(MOTW, OS, IsLittleEndian); break;
1253     case ELF::EM_MBLAZE:
1254       return new MBlazeELFObjectWriter(MOTW, OS, IsLittleEndian); break;
1255     default: llvm_unreachable("Unsupported architecture"); break;
1256   }
1257 }
1258
1259
1260 /// START OF SUBCLASSES for ELFObjectWriter
1261 //===- ARMELFObjectWriter -------------------------------------------===//
1262
1263 ARMELFObjectWriter::ARMELFObjectWriter(MCELFObjectTargetWriter *MOTW,
1264                                        raw_ostream &_OS,
1265                                        bool IsLittleEndian)
1266   : ELFObjectWriter(MOTW, _OS, IsLittleEndian)
1267 {}
1268
1269 ARMELFObjectWriter::~ARMELFObjectWriter()
1270 {}
1271
1272 // FIXME: get the real EABI Version from the Triple.
1273 void ARMELFObjectWriter::WriteEFlags() {
1274   Write32(ELF::EF_ARM_EABIMASK & DefaultEABIVersion);
1275 }
1276
1277 // In ARM, _MergedGlobals and other most symbols get emitted directly.
1278 // I.e. not as an offset to a section symbol.
1279 // This code is an approximation of what ARM/gcc does.
1280
1281 STATISTIC(PCRelCount, "Total number of PIC Relocations");
1282 STATISTIC(NonPCRelCount, "Total number of non-PIC relocations");
1283
1284 const MCSymbol *ARMELFObjectWriter::ExplicitRelSym(const MCAssembler &Asm,
1285                                                    const MCValue &Target,
1286                                                    const MCFragment &F,
1287                                                    const MCFixup &Fixup,
1288                                                    bool IsPCRel) const {
1289   const MCSymbol &Symbol = Target.getSymA()->getSymbol();
1290   bool EmitThisSym = false;
1291
1292   const MCSectionELF &Section =
1293     static_cast<const MCSectionELF&>(Symbol.getSection());
1294   bool InNormalSection = true;
1295   unsigned RelocType = 0;
1296   RelocType = GetRelocTypeInner(Target, Fixup, IsPCRel);
1297
1298   DEBUG(
1299       const MCSymbolRefExpr::VariantKind Kind = Target.getSymA()->getKind();
1300       MCSymbolRefExpr::VariantKind Kind2;
1301       Kind2 = Target.getSymB() ?  Target.getSymB()->getKind() :
1302         MCSymbolRefExpr::VK_None;
1303       dbgs() << "considering symbol "
1304         << Section.getSectionName() << "/"
1305         << Symbol.getName() << "/"
1306         << " Rel:" << (unsigned)RelocType
1307         << " Kind: " << (int)Kind << "/" << (int)Kind2
1308         << " Tmp:"
1309         << Symbol.isAbsolute() << "/" << Symbol.isDefined() << "/"
1310         << Symbol.isVariable() << "/" << Symbol.isTemporary()
1311         << " Counts:" << PCRelCount << "/" << NonPCRelCount << "\n");
1312
1313   if (IsPCRel) { ++PCRelCount;
1314     switch (RelocType) {
1315     default:
1316       // Most relocation types are emitted as explicit symbols
1317       InNormalSection =
1318         StringSwitch<bool>(Section.getSectionName())
1319         .Case(".data.rel.ro.local", false)
1320         .Case(".data.rel", false)
1321         .Case(".bss", false)
1322         .Default(true);
1323       EmitThisSym = true;
1324       break;
1325     case ELF::R_ARM_ABS32:
1326       // But things get strange with R_ARM_ABS32
1327       // In this case, most things that go in .rodata show up
1328       // as section relative relocations
1329       InNormalSection =
1330         StringSwitch<bool>(Section.getSectionName())
1331         .Case(".data.rel.ro.local", false)
1332         .Case(".data.rel", false)
1333         .Case(".rodata", false)
1334         .Case(".bss", false)
1335         .Default(true);
1336       EmitThisSym = false;
1337       break;
1338     }
1339   } else {
1340     NonPCRelCount++;
1341     InNormalSection =
1342       StringSwitch<bool>(Section.getSectionName())
1343       .Case(".data.rel.ro.local", false)
1344       .Case(".rodata", false)
1345       .Case(".data.rel", false)
1346       .Case(".bss", false)
1347       .Default(true);
1348
1349     switch (RelocType) {
1350     default: EmitThisSym = true; break;
1351     case ELF::R_ARM_ABS32: EmitThisSym = false; break;
1352     }
1353   }
1354
1355   if (EmitThisSym)
1356     return &Symbol;
1357   if (! Symbol.isTemporary() && InNormalSection) {
1358     return &Symbol;
1359   }
1360   return NULL;
1361 }
1362
1363 // Need to examine the Fixup when determining whether to
1364 // emit the relocation as an explicit symbol or as a section relative
1365 // offset
1366 unsigned ARMELFObjectWriter::GetRelocType(const MCValue &Target,
1367                                           const MCFixup &Fixup,
1368                                           bool IsPCRel,
1369                                           bool IsRelocWithSymbol,
1370                                           int64_t Addend) {
1371   MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
1372     MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
1373
1374   unsigned Type = GetRelocTypeInner(Target, Fixup, IsPCRel);
1375
1376   if (RelocNeedsGOT(Modifier))
1377     NeedsGOT = true;
1378
1379   return Type;
1380 }
1381
1382 unsigned ARMELFObjectWriter::GetRelocTypeInner(const MCValue &Target,
1383                                                const MCFixup &Fixup,
1384                                                bool IsPCRel) const  {
1385   MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
1386     MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
1387
1388   unsigned Type = 0;
1389   if (IsPCRel) {
1390     switch ((unsigned)Fixup.getKind()) {
1391     default: assert(0 && "Unimplemented");
1392     case FK_Data_4:
1393       switch (Modifier) {
1394       default: llvm_unreachable("Unsupported Modifier");
1395       case MCSymbolRefExpr::VK_None:
1396         Type = ELF::R_ARM_REL32;
1397         break;
1398       case MCSymbolRefExpr::VK_ARM_TLSGD:
1399         assert(0 && "unimplemented");
1400         break;
1401       case MCSymbolRefExpr::VK_ARM_GOTTPOFF:
1402         Type = ELF::R_ARM_TLS_IE32;
1403         break;
1404       }
1405       break;
1406     case ARM::fixup_arm_uncondbranch:
1407       switch (Modifier) {
1408       case MCSymbolRefExpr::VK_ARM_PLT:
1409         Type = ELF::R_ARM_PLT32;
1410         break;
1411       default:
1412         Type = ELF::R_ARM_CALL;
1413         break;
1414       }
1415       break;
1416     case ARM::fixup_arm_condbranch:
1417       Type = ELF::R_ARM_JUMP24;
1418       break;
1419     case ARM::fixup_arm_movt_hi16:
1420     case ARM::fixup_arm_movt_hi16_pcrel:
1421       Type = ELF::R_ARM_MOVT_PREL;
1422       break;
1423     case ARM::fixup_arm_movw_lo16:
1424     case ARM::fixup_arm_movw_lo16_pcrel:
1425       Type = ELF::R_ARM_MOVW_PREL_NC;
1426       break;
1427     case ARM::fixup_t2_movt_hi16:
1428     case ARM::fixup_t2_movt_hi16_pcrel:
1429       Type = ELF::R_ARM_THM_MOVT_PREL;
1430       break;
1431     case ARM::fixup_t2_movw_lo16:
1432     case ARM::fixup_t2_movw_lo16_pcrel:
1433       Type = ELF::R_ARM_THM_MOVW_PREL_NC;
1434       break;
1435     case ARM::fixup_arm_thumb_bl:
1436     case ARM::fixup_arm_thumb_blx:
1437       switch (Modifier) {
1438       case MCSymbolRefExpr::VK_ARM_PLT:
1439         Type = ELF::R_ARM_THM_CALL;
1440         break;
1441       default:
1442         Type = ELF::R_ARM_NONE;
1443         break;
1444       }
1445       break;
1446     }
1447   } else {
1448     switch ((unsigned)Fixup.getKind()) {
1449     default: llvm_unreachable("invalid fixup kind!");
1450     case FK_Data_4:
1451       switch (Modifier) {
1452       default: llvm_unreachable("Unsupported Modifier"); break;
1453       case MCSymbolRefExpr::VK_ARM_GOT:
1454         Type = ELF::R_ARM_GOT_BREL;
1455         break;
1456       case MCSymbolRefExpr::VK_ARM_TLSGD:
1457         Type = ELF::R_ARM_TLS_GD32;
1458         break;
1459       case MCSymbolRefExpr::VK_ARM_TPOFF:
1460         Type = ELF::R_ARM_TLS_LE32;
1461         break;
1462       case MCSymbolRefExpr::VK_ARM_GOTTPOFF:
1463         Type = ELF::R_ARM_TLS_IE32;
1464         break;
1465       case MCSymbolRefExpr::VK_None:
1466         Type = ELF::R_ARM_ABS32;
1467         break;
1468       case MCSymbolRefExpr::VK_ARM_GOTOFF:
1469         Type = ELF::R_ARM_GOTOFF32;
1470         break;
1471       }
1472       break;
1473     case ARM::fixup_arm_ldst_pcrel_12:
1474     case ARM::fixup_arm_pcrel_10:
1475     case ARM::fixup_arm_adr_pcrel_12:
1476     case ARM::fixup_arm_thumb_bl:
1477     case ARM::fixup_arm_thumb_cb:
1478     case ARM::fixup_arm_thumb_cp:
1479     case ARM::fixup_arm_thumb_br:
1480       assert(0 && "Unimplemented");
1481       break;
1482     case ARM::fixup_arm_uncondbranch:
1483       Type = ELF::R_ARM_CALL;
1484       break;
1485     case ARM::fixup_arm_condbranch:
1486       Type = ELF::R_ARM_JUMP24;
1487       break;
1488     case ARM::fixup_arm_movt_hi16:
1489       Type = ELF::R_ARM_MOVT_ABS;
1490       break;
1491     case ARM::fixup_arm_movw_lo16:
1492       Type = ELF::R_ARM_MOVW_ABS_NC;
1493       break;
1494     case ARM::fixup_t2_movt_hi16:
1495       Type = ELF::R_ARM_THM_MOVT_ABS;
1496       break;
1497     case ARM::fixup_t2_movw_lo16:
1498       Type = ELF::R_ARM_THM_MOVW_ABS_NC;
1499       break;
1500     }
1501   }
1502
1503   return Type;
1504 }
1505
1506 //===- MBlazeELFObjectWriter -------------------------------------------===//
1507
1508 MBlazeELFObjectWriter::MBlazeELFObjectWriter(MCELFObjectTargetWriter *MOTW,
1509                                              raw_ostream &_OS,
1510                                              bool IsLittleEndian)
1511   : ELFObjectWriter(MOTW, _OS, IsLittleEndian) {
1512 }
1513
1514 MBlazeELFObjectWriter::~MBlazeELFObjectWriter() {
1515 }
1516
1517 unsigned MBlazeELFObjectWriter::GetRelocType(const MCValue &Target,
1518                                              const MCFixup &Fixup,
1519                                              bool IsPCRel,
1520                                              bool IsRelocWithSymbol,
1521                                              int64_t Addend) {
1522   // determine the type of the relocation
1523   unsigned Type;
1524   if (IsPCRel) {
1525     switch ((unsigned)Fixup.getKind()) {
1526     default:
1527       llvm_unreachable("Unimplemented");
1528     case FK_PCRel_4:
1529       Type = ELF::R_MICROBLAZE_64_PCREL;
1530       break;
1531     case FK_PCRel_2:
1532       Type = ELF::R_MICROBLAZE_32_PCREL;
1533       break;
1534     }
1535   } else {
1536     switch ((unsigned)Fixup.getKind()) {
1537     default: llvm_unreachable("invalid fixup kind!");
1538     case FK_Data_4:
1539       Type = ((IsRelocWithSymbol || Addend !=0)
1540               ? ELF::R_MICROBLAZE_32
1541               : ELF::R_MICROBLAZE_64);
1542       break;
1543     case FK_Data_2:
1544       Type = ELF::R_MICROBLAZE_32;
1545       break;
1546     }
1547   }
1548   return Type;
1549 }
1550
1551 //===- X86ELFObjectWriter -------------------------------------------===//
1552
1553
1554 X86ELFObjectWriter::X86ELFObjectWriter(MCELFObjectTargetWriter *MOTW,
1555                                        raw_ostream &_OS,
1556                                        bool IsLittleEndian)
1557   : ELFObjectWriter(MOTW, _OS, IsLittleEndian)
1558 {}
1559
1560 X86ELFObjectWriter::~X86ELFObjectWriter()
1561 {}
1562
1563 unsigned X86ELFObjectWriter::GetRelocType(const MCValue &Target,
1564                                           const MCFixup &Fixup,
1565                                           bool IsPCRel,
1566                                           bool IsRelocWithSymbol,
1567                                           int64_t Addend) {
1568   // determine the type of the relocation
1569
1570   MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
1571     MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
1572   unsigned Type;
1573   if (is64Bit()) {
1574     if (IsPCRel) {
1575       switch ((unsigned)Fixup.getKind()) {
1576       default: llvm_unreachable("invalid fixup kind!");
1577
1578       case FK_Data_8: Type = ELF::R_X86_64_PC64; break;
1579       case FK_Data_4: Type = ELF::R_X86_64_PC32; break;
1580       case FK_Data_2: Type = ELF::R_X86_64_PC16; break;
1581
1582       case FK_PCRel_8:
1583         assert(Modifier == MCSymbolRefExpr::VK_None);
1584         Type = ELF::R_X86_64_PC64;
1585         break;
1586       case X86::reloc_signed_4byte:
1587       case X86::reloc_riprel_4byte_movq_load:
1588       case X86::reloc_riprel_4byte:
1589       case FK_PCRel_4:
1590         switch (Modifier) {
1591         default:
1592           llvm_unreachable("Unimplemented");
1593         case MCSymbolRefExpr::VK_None:
1594           Type = ELF::R_X86_64_PC32;
1595           break;
1596         case MCSymbolRefExpr::VK_PLT:
1597           Type = ELF::R_X86_64_PLT32;
1598           break;
1599         case MCSymbolRefExpr::VK_GOTPCREL:
1600           Type = ELF::R_X86_64_GOTPCREL;
1601           break;
1602         case MCSymbolRefExpr::VK_GOTTPOFF:
1603           Type = ELF::R_X86_64_GOTTPOFF;
1604         break;
1605         case MCSymbolRefExpr::VK_TLSGD:
1606           Type = ELF::R_X86_64_TLSGD;
1607           break;
1608         case MCSymbolRefExpr::VK_TLSLD:
1609           Type = ELF::R_X86_64_TLSLD;
1610           break;
1611         }
1612         break;
1613       case FK_PCRel_2:
1614         assert(Modifier == MCSymbolRefExpr::VK_None);
1615         Type = ELF::R_X86_64_PC16;
1616         break;
1617       case FK_PCRel_1:
1618         assert(Modifier == MCSymbolRefExpr::VK_None);
1619         Type = ELF::R_X86_64_PC8;
1620         break;
1621       }
1622     } else {
1623       switch ((unsigned)Fixup.getKind()) {
1624       default: llvm_unreachable("invalid fixup kind!");
1625       case FK_Data_8: Type = ELF::R_X86_64_64; break;
1626       case X86::reloc_signed_4byte:
1627         assert(isInt<32>(Target.getConstant()));
1628         switch (Modifier) {
1629         default:
1630           llvm_unreachable("Unimplemented");
1631         case MCSymbolRefExpr::VK_None:
1632           Type = ELF::R_X86_64_32S;
1633           break;
1634         case MCSymbolRefExpr::VK_GOT:
1635           Type = ELF::R_X86_64_GOT32;
1636           break;
1637         case MCSymbolRefExpr::VK_GOTPCREL:
1638           Type = ELF::R_X86_64_GOTPCREL;
1639           break;
1640         case MCSymbolRefExpr::VK_TPOFF:
1641           Type = ELF::R_X86_64_TPOFF32;
1642           break;
1643         case MCSymbolRefExpr::VK_DTPOFF:
1644           Type = ELF::R_X86_64_DTPOFF32;
1645           break;
1646         }
1647         break;
1648       case FK_Data_4:
1649         Type = ELF::R_X86_64_32;
1650         break;
1651       case FK_Data_2: Type = ELF::R_X86_64_16; break;
1652       case FK_PCRel_1:
1653       case FK_Data_1: Type = ELF::R_X86_64_8; break;
1654       }
1655     }
1656   } else {
1657     if (IsPCRel) {
1658       switch (Modifier) {
1659       default:
1660         llvm_unreachable("Unimplemented");
1661       case MCSymbolRefExpr::VK_None:
1662         Type = ELF::R_386_PC32;
1663         break;
1664       case MCSymbolRefExpr::VK_PLT:
1665         Type = ELF::R_386_PLT32;
1666         break;
1667       }
1668     } else {
1669       switch ((unsigned)Fixup.getKind()) {
1670       default: llvm_unreachable("invalid fixup kind!");
1671
1672       case X86::reloc_global_offset_table:
1673         Type = ELF::R_386_GOTPC;
1674         break;
1675
1676       // FIXME: Should we avoid selecting reloc_signed_4byte in 32 bit mode
1677       // instead?
1678       case X86::reloc_signed_4byte:
1679       case FK_PCRel_4:
1680       case FK_Data_4:
1681         switch (Modifier) {
1682         default:
1683           llvm_unreachable("Unimplemented");
1684         case MCSymbolRefExpr::VK_None:
1685           Type = ELF::R_386_32;
1686           break;
1687         case MCSymbolRefExpr::VK_GOT:
1688           Type = ELF::R_386_GOT32;
1689           break;
1690         case MCSymbolRefExpr::VK_GOTOFF:
1691           Type = ELF::R_386_GOTOFF;
1692           break;
1693         case MCSymbolRefExpr::VK_TLSGD:
1694           Type = ELF::R_386_TLS_GD;
1695           break;
1696         case MCSymbolRefExpr::VK_TPOFF:
1697           Type = ELF::R_386_TLS_LE_32;
1698           break;
1699         case MCSymbolRefExpr::VK_INDNTPOFF:
1700           Type = ELF::R_386_TLS_IE;
1701           break;
1702         case MCSymbolRefExpr::VK_NTPOFF:
1703           Type = ELF::R_386_TLS_LE;
1704           break;
1705         case MCSymbolRefExpr::VK_GOTNTPOFF:
1706           Type = ELF::R_386_TLS_GOTIE;
1707           break;
1708         case MCSymbolRefExpr::VK_TLSLDM:
1709           Type = ELF::R_386_TLS_LDM;
1710           break;
1711         case MCSymbolRefExpr::VK_DTPOFF:
1712           Type = ELF::R_386_TLS_LDO_32;
1713           break;
1714         case MCSymbolRefExpr::VK_GOTTPOFF:
1715           Type = ELF::R_386_TLS_IE_32;
1716           break;
1717         }
1718         break;
1719       case FK_Data_2: Type = ELF::R_386_16; break;
1720       case FK_PCRel_1:
1721       case FK_Data_1: Type = ELF::R_386_8; break;
1722       }
1723     }
1724   }
1725
1726   if (RelocNeedsGOT(Modifier))
1727     NeedsGOT = true;
1728
1729   return Type;
1730 }