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[oota-llvm.git] / lib / MC / ELFObjectWriter.cpp
index d58cd48004bc113208b4449132c9c02f66fca4cf..5b10fbbe75daf9d61b5a2f17ccd10fbcf9213a02 100644 (file)
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/MC/MCELFObjectWriter.h"
+#include "MCELF.h"
 #include "llvm/ADT/OwningPtr.h"
-#include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringMap.h"
-#include "llvm/ADT/Twine.h"
-#include "llvm/MC/MCAssembler.h"
+#include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCAsmLayout.h"
+#include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCELFSymbolFlags.h"
 #include "llvm/MC/MCExpr.h"
-#include "llvm/MC/MCELFObjectWriter.h"
+#include "llvm/MC/MCFixupKindInfo.h"
 #include "llvm/MC/MCObjectWriter.h"
 #include "llvm/MC/MCSectionELF.h"
-#include "llvm/MC/MCSymbol.h"
 #include "llvm/MC/MCValue.h"
 #include "llvm/Support/Debug.h"
-#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ELF.h"
-#include "llvm/Target/TargetAsmBackend.h"
-
-#include "../Target/X86/X86FixupKinds.h"
-#include "../Target/ARM/ARMFixupKinds.h"
-
+#include "llvm/Support/ErrorHandling.h"
 #include <vector>
 using namespace llvm;
 
-static unsigned GetType(const MCSymbolData &SD) {
-  uint32_t Type = (SD.getFlags() & (0xf << ELF_STT_Shift)) >> ELF_STT_Shift;
-  assert(Type == ELF::STT_NOTYPE || Type == ELF::STT_OBJECT ||
-         Type == ELF::STT_FUNC || Type == ELF::STT_SECTION ||
-         Type == ELF::STT_FILE || Type == ELF::STT_COMMON ||
-         Type == ELF::STT_TLS);
-  return Type;
-}
-
-static unsigned GetBinding(const MCSymbolData &SD) {
-  uint32_t Binding = (SD.getFlags() & (0xf << ELF_STB_Shift)) >> ELF_STB_Shift;
-  assert(Binding == ELF::STB_LOCAL || Binding == ELF::STB_GLOBAL ||
-         Binding == ELF::STB_WEAK);
-  return Binding;
-}
-
-static void SetBinding(MCSymbolData &SD, unsigned Binding) {
-  assert(Binding == ELF::STB_LOCAL || Binding == ELF::STB_GLOBAL ||
-         Binding == ELF::STB_WEAK);
-  uint32_t OtherFlags = SD.getFlags() & ~(0xf << ELF_STB_Shift);
-  SD.setFlags(OtherFlags | (Binding << ELF_STB_Shift));
-}
-
-static unsigned GetVisibility(MCSymbolData &SD) {
-  unsigned Visibility =
-    (SD.getFlags() & (0xf << ELF_STV_Shift)) >> ELF_STV_Shift;
-  assert(Visibility == ELF::STV_DEFAULT || Visibility == ELF::STV_INTERNAL ||
-         Visibility == ELF::STV_HIDDEN || Visibility == ELF::STV_PROTECTED);
-  return Visibility;
-}
-
-
-static bool RelocNeedsGOT(MCSymbolRefExpr::VariantKind Variant) {
-  switch (Variant) {
-  default:
-    return false;
-  case MCSymbolRefExpr::VK_GOT:
-  case MCSymbolRefExpr::VK_PLT:
-  case MCSymbolRefExpr::VK_GOTPCREL:
-  case MCSymbolRefExpr::VK_TPOFF:
-  case MCSymbolRefExpr::VK_TLSGD:
-  case MCSymbolRefExpr::VK_GOTTPOFF:
-  case MCSymbolRefExpr::VK_INDNTPOFF:
-  case MCSymbolRefExpr::VK_NTPOFF:
-  case MCSymbolRefExpr::VK_GOTNTPOFF:
-  case MCSymbolRefExpr::VK_TLSLDM:
-  case MCSymbolRefExpr::VK_DTPOFF:
-  case MCSymbolRefExpr::VK_TLSLD:
-    return true;
-  }
-}
-
-static bool isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind) {
-  const MCFixupKindInfo &FKI =
-    Asm.getBackend().getFixupKindInfo((MCFixupKind) Kind);
-
-  return FKI.Flags & MCFixupKindInfo::FKF_IsPCRel;
-}
+#undef  DEBUG_TYPE
+#define DEBUG_TYPE "reloc-info"
 
 namespace {
-  class ELFObjectWriter : public MCObjectWriter {
+class ELFObjectWriter : public MCObjectWriter {
   protected:
+
+    static bool isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind);
+    static bool RelocNeedsGOT(MCSymbolRefExpr::VariantKind Variant);
+    static uint64_t SymbolValue(MCSymbolData &Data, const MCAsmLayout &Layout);
+    static bool isInSymtab(const MCAssembler &Asm, const MCSymbolData &Data,
+                           bool Used, bool Renamed);
+    static bool isLocal(const MCSymbolData &Data, bool isSignature,
+                        bool isUsedInReloc);
+    static bool IsELFMetaDataSection(const MCSectionData &SD);
+    static uint64_t DataSectionSize(const MCSectionData &SD);
+    static uint64_t GetSectionFileSize(const MCAsmLayout &Layout,
+                                       const MCSectionData &SD);
+    static uint64_t GetSectionAddressSize(const MCAsmLayout &Layout,
+                                          const MCSectionData &SD);
+
+    void WriteDataSectionData(MCAssembler &Asm,
+                              const MCAsmLayout &Layout,
+                              const MCSectionELF &Section);
+
     /*static bool isFixupKindX86RIPRel(unsigned Kind) {
       return Kind == X86::reloc_riprel_4byte ||
         Kind == X86::reloc_riprel_4byte_movq_load;
     }*/
 
-
-    /// ELFSymbolData - Helper struct for containing some precomputed information
-    /// on symbols.
+    /// ELFSymbolData - Helper struct for containing some precomputed
+    /// information on symbols.
     struct ELFSymbolData {
       MCSymbolData *SymbolData;
       uint64_t StringIndex;
@@ -114,41 +73,15 @@ namespace {
 
       // Support lexicographic sorting.
       bool operator<(const ELFSymbolData &RHS) const {
-        if (GetType(*SymbolData) == ELF::STT_FILE)
+        if (MCELF::GetType(*SymbolData) == ELF::STT_FILE)
           return true;
-        if (GetType(*RHS.SymbolData) == ELF::STT_FILE)
+        if (MCELF::GetType(*RHS.SymbolData) == ELF::STT_FILE)
           return false;
         return SymbolData->getSymbol().getName() <
                RHS.SymbolData->getSymbol().getName();
       }
     };
 
-    /// @name Relocation Data
-    /// @{
-
-    struct ELFRelocationEntry {
-      // Make these big enough for both 32-bit and 64-bit
-      uint64_t r_offset;
-      int Index;
-      unsigned Type;
-      const MCSymbol *Symbol;
-      uint64_t r_addend;
-
-      ELFRelocationEntry()
-        : r_offset(0), Index(0), Type(0), Symbol(0), r_addend(0) {}
-
-      ELFRelocationEntry(uint64_t RelocOffset, int Idx,
-                         unsigned RelType, const MCSymbol *Sym,
-                         uint64_t Addend)
-        : r_offset(RelocOffset), Index(Idx), Type(RelType),
-          Symbol(Sym), r_addend(Addend) {}
-
-      // Support lexicographic sorting.
-      bool operator<(const ELFRelocationEntry &RE) const {
-        return RE.r_offset < r_offset;
-      }
-    };
-
     /// The target specific ELF writer instance.
     llvm::OwningPtr<MCELFObjectTargetWriter> TargetObjectWriter;
 
@@ -187,12 +120,38 @@ namespace {
 
     const MCSymbol *SymbolToReloc(const MCAssembler &Asm,
                                   const MCValue &Target,
-                                  const MCFragment &F) const;
+                                  const MCFragment &F,
+                                  const MCFixup &Fixup,
+                                  bool IsPCRel) const;
+
+    // TargetObjectWriter wrappers.
+    const MCSymbol *ExplicitRelSym(const MCAssembler &Asm,
+                                   const MCValue &Target,
+                                   const MCFragment &F,
+                                   const MCFixup &Fixup,
+                                   bool IsPCRel) const {
+      return TargetObjectWriter->ExplicitRelSym(Asm, Target, F, Fixup, IsPCRel);
+    }
+    const MCSymbol *undefinedExplicitRelSym(const MCValue &Target,
+                                            const MCFixup &Fixup,
+                                            bool IsPCRel) const {
+      return TargetObjectWriter->undefinedExplicitRelSym(Target, Fixup, IsPCRel);
+    }
 
     bool is64Bit() const { return TargetObjectWriter->is64Bit(); }
     bool hasRelocationAddend() const {
       return TargetObjectWriter->hasRelocationAddend();
     }
+    unsigned getEFlags() const {
+      return TargetObjectWriter->getEFlags();
+    }
+    unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
+                          bool IsPCRel, bool IsRelocWithSymbol,
+                          int64_t Addend) const {
+      return TargetObjectWriter->GetRelocType(Target, Fixup, IsPCRel,
+                                              IsRelocWithSymbol, Addend);
+    }
+
 
   public:
     ELFObjectWriter(MCELFObjectTargetWriter *MOTW,
@@ -274,75 +233,97 @@ namespace {
       F.getContents() += StringRef(buf, 8);
     }
 
-    virtual void WriteHeader(uint64_t SectionDataSize, unsigned NumberOfSections);
+    void WriteHeader(uint64_t SectionDataSize,
+                     unsigned NumberOfSections);
 
-    virtual void WriteSymbolEntry(MCDataFragment *SymtabF, MCDataFragment *ShndxF,
+    void WriteSymbolEntry(MCDataFragment *SymtabF,
+                          MCDataFragment *ShndxF,
                           uint64_t name, uint8_t info,
                           uint64_t value, uint64_t size,
                           uint8_t other, uint32_t shndx,
                           bool Reserved);
 
-    virtual void WriteSymbol(MCDataFragment *SymtabF,  MCDataFragment *ShndxF,
+    void WriteSymbol(MCDataFragment *SymtabF,  MCDataFragment *ShndxF,
                      ELFSymbolData &MSD,
                      const MCAsmLayout &Layout);
 
     typedef DenseMap<const MCSectionELF*, uint32_t> SectionIndexMapTy;
-    virtual void WriteSymbolTable(MCDataFragment *SymtabF, MCDataFragment *ShndxF,
+    void WriteSymbolTable(MCDataFragment *SymtabF,
+                          MCDataFragment *ShndxF,
                           const MCAssembler &Asm,
                           const MCAsmLayout &Layout,
                           const SectionIndexMapTy &SectionIndexMap);
 
-    virtual void RecordRelocation(const MCAssembler &Asm, const MCAsmLayout &Layout,
-                                  const MCFragment *Fragment, const MCFixup &Fixup,
+    virtual void RecordRelocation(const MCAssembler &Asm,
+                                  const MCAsmLayout &Layout,
+                                  const MCFragment *Fragment,
+                                  const MCFixup &Fixup,
                                   MCValue Target, uint64_t &FixedValue);
 
-    virtual uint64_t getSymbolIndexInSymbolTable(const MCAssembler &Asm,
+    uint64_t getSymbolIndexInSymbolTable(const MCAssembler &Asm,
                                          const MCSymbol *S);
 
     // Map from a group section to the signature symbol
     typedef DenseMap<const MCSectionELF*, const MCSymbol*> GroupMapTy;
     // Map from a signature symbol to the group section
     typedef DenseMap<const MCSymbol*, const MCSectionELF*> RevGroupMapTy;
+    // Map from a section to the section with the relocations
+    typedef DenseMap<const MCSectionELF*, const MCSectionELF*> RelMapTy;
+    // Map from a section to its offset
+    typedef DenseMap<const MCSectionELF*, uint64_t> SectionOffsetMapTy;
 
     /// ComputeSymbolTable - Compute the symbol table data
     ///
-    /// \param StringTable [out] - The string table data.
-    /// \param StringIndexMap [out] - Map from symbol names to offsets in the
-    /// string table.
-    virtual void ComputeSymbolTable(MCAssembler &Asm,
+    /// \param Asm - The assembler.
+    /// \param SectionIndexMap - Maps a section to its index.
+    /// \param RevGroupMap - Maps a signature symbol to the group section.
+    /// \param NumRegularSections - Number of non-relocation sections.
+    void ComputeSymbolTable(MCAssembler &Asm,
                             const SectionIndexMapTy &SectionIndexMap,
-                            RevGroupMapTy RevGroupMap);
+                            RevGroupMapTy RevGroupMap,
+                            unsigned NumRegularSections);
 
-    virtual void ComputeIndexMap(MCAssembler &Asm,
-                         SectionIndexMapTy &SectionIndexMap);
+    void ComputeIndexMap(MCAssembler &Asm,
+                         SectionIndexMapTy &SectionIndexMap,
+                         const RelMapTy &RelMap);
 
-    virtual void WriteRelocation(MCAssembler &Asm, MCAsmLayout &Layout,
-                         const MCSectionData &SD);
+    void CreateRelocationSections(MCAssembler &Asm, MCAsmLayout &Layout,
+                                  RelMapTy &RelMap);
 
-    virtual void WriteRelocations(MCAssembler &Asm, MCAsmLayout &Layout) {
-      for (MCAssembler::const_iterator it = Asm.begin(),
-             ie = Asm.end(); it != ie; ++it) {
-        WriteRelocation(Asm, Layout, *it);
-      }
-    }
+    void WriteRelocations(MCAssembler &Asm, MCAsmLayout &Layout,
+                          const RelMapTy &RelMap);
 
-    virtual void CreateMetadataSections(MCAssembler &Asm, MCAsmLayout &Layout,
-                                const SectionIndexMapTy &SectionIndexMap);
+    void CreateMetadataSections(MCAssembler &Asm, MCAsmLayout &Layout,
+                                SectionIndexMapTy &SectionIndexMap,
+                                const RelMapTy &RelMap);
 
-    virtual void CreateGroupSections(MCAssembler &Asm, MCAsmLayout &Layout,
-                             GroupMapTy &GroupMap, RevGroupMapTy &RevGroupMap);
+    // Create the sections that show up in the symbol table. Currently
+    // those are the .note.GNU-stack section and the group sections.
+    void CreateIndexedSections(MCAssembler &Asm, MCAsmLayout &Layout,
+                               GroupMapTy &GroupMap,
+                               RevGroupMapTy &RevGroupMap,
+                               SectionIndexMapTy &SectionIndexMap,
+                               const RelMapTy &RelMap);
 
     virtual void ExecutePostLayoutBinding(MCAssembler &Asm,
                                           const MCAsmLayout &Layout);
 
-    virtual void WriteSecHdrEntry(uint32_t Name, uint32_t Type, uint64_t Flags,
+    void WriteSectionHeader(MCAssembler &Asm, const GroupMapTy &GroupMap,
+                            const MCAsmLayout &Layout,
+                            const SectionIndexMapTy &SectionIndexMap,
+                            const SectionOffsetMapTy &SectionOffsetMap);
+
+    void ComputeSectionOrder(MCAssembler &Asm,
+                             std::vector<const MCSectionELF*> &Sections);
+
+    void WriteSecHdrEntry(uint32_t Name, uint32_t Type, uint64_t Flags,
                           uint64_t Address, uint64_t Offset,
                           uint64_t Size, uint32_t Link, uint32_t Info,
                           uint64_t Alignment, uint64_t EntrySize);
 
-    virtual void WriteRelocationsFragment(const MCAssembler &Asm,
-                                          MCDataFragment *F,
-                                          const MCSectionData *SD);
+    void WriteRelocationsFragment(const MCAssembler &Asm,
+                                  MCDataFragment *F,
+                                  const MCSectionData *SD);
 
     virtual bool
     IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
@@ -352,63 +333,40 @@ namespace {
                                            bool IsPCRel) const;
 
     virtual void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout);
-    virtual void WriteSection(MCAssembler &Asm,
+    void WriteSection(MCAssembler &Asm,
                       const SectionIndexMapTy &SectionIndexMap,
                       uint32_t GroupSymbolIndex,
                       uint64_t Offset, uint64_t Size, uint64_t Alignment,
                       const MCSectionELF &Section);
-
-  protected:
-    virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
-                                  bool IsPCRel, bool IsRelocWithSymbol,
-                                  int64_t Addend) = 0;
-  };
-
-  //===- X86ELFObjectWriter -------------------------------------------===//
-
-  class X86ELFObjectWriter : public ELFObjectWriter {
-  public:
-    X86ELFObjectWriter(MCELFObjectTargetWriter *MOTW,
-                       raw_ostream &_OS,
-                       bool IsLittleEndian);
-
-    virtual ~X86ELFObjectWriter();
-  protected:
-    virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
-                                  bool IsPCRel, bool IsRelocWithSymbol,
-                                  int64_t Addend);
-  };
-
-
-  //===- ARMELFObjectWriter -------------------------------------------===//
-
-  class ARMELFObjectWriter : public ELFObjectWriter {
-  public:
-    ARMELFObjectWriter(MCELFObjectTargetWriter *MOTW,
-                       raw_ostream &_OS,
-                       bool IsLittleEndian);
-
-    virtual ~ARMELFObjectWriter();
-  protected:
-    virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
-                                  bool IsPCRel, bool IsRelocWithSymbol,
-                                  int64_t Addend);
   };
+}
 
-  //===- MBlazeELFObjectWriter -------------------------------------------===//
+bool ELFObjectWriter::isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind) {
+  const MCFixupKindInfo &FKI =
+    Asm.getBackend().getFixupKindInfo((MCFixupKind) Kind);
 
-  class MBlazeELFObjectWriter : public ELFObjectWriter {
-  public:
-    MBlazeELFObjectWriter(MCELFObjectTargetWriter *MOTW,
-                          raw_ostream &_OS,
-                          bool IsLittleEndian);
+  return FKI.Flags & MCFixupKindInfo::FKF_IsPCRel;
+}
 
-    virtual ~MBlazeELFObjectWriter();
-  protected:
-    virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
-                                  bool IsPCRel, bool IsRelocWithSymbol,
-                                  int64_t Addend);
-  };
+bool ELFObjectWriter::RelocNeedsGOT(MCSymbolRefExpr::VariantKind Variant) {
+  switch (Variant) {
+  default:
+    return false;
+  case MCSymbolRefExpr::VK_GOT:
+  case MCSymbolRefExpr::VK_PLT:
+  case MCSymbolRefExpr::VK_GOTPCREL:
+  case MCSymbolRefExpr::VK_GOTOFF:
+  case MCSymbolRefExpr::VK_TPOFF:
+  case MCSymbolRefExpr::VK_TLSGD:
+  case MCSymbolRefExpr::VK_GOTTPOFF:
+  case MCSymbolRefExpr::VK_INDNTPOFF:
+  case MCSymbolRefExpr::VK_NTPOFF:
+  case MCSymbolRefExpr::VK_GOTNTPOFF:
+  case MCSymbolRefExpr::VK_TLSLDM:
+  case MCSymbolRefExpr::VK_DTPOFF:
+  case MCSymbolRefExpr::VK_TLSLD:
+    return true;
+  }
 }
 
 ELFObjectWriter::~ELFObjectWriter()
@@ -437,11 +395,7 @@ void ELFObjectWriter::WriteHeader(uint64_t SectionDataSize,
 
   Write8(ELF::EV_CURRENT);        // e_ident[EI_VERSION]
   // e_ident[EI_OSABI]
-  switch (TargetObjectWriter->getOSType()) {
-    case Triple::FreeBSD:  Write8(ELF::ELFOSABI_FREEBSD); break;
-    case Triple::Linux:    Write8(ELF::ELFOSABI_LINUX); break;
-    default:               Write8(ELF::ELFOSABI_NONE); break;
-  }
+  Write8(TargetObjectWriter->getOSABI());
   Write8(0);                  // e_ident[EI_ABIVERSION]
 
   WriteZeros(ELF::EI_NIDENT - ELF::EI_PAD);
@@ -456,8 +410,8 @@ void ELFObjectWriter::WriteHeader(uint64_t SectionDataSize,
   WriteWord(SectionDataSize + (is64Bit() ? sizeof(ELF::Elf64_Ehdr) :
             sizeof(ELF::Elf32_Ehdr)));  // e_shoff = sec hdr table off in bytes
 
-  // FIXME: Make this configurable.
-  Write32(0);   // e_flags = whatever the target wants
+  // e_flags = whatever the target wants
+  Write32(getEFlags());
 
   // e_ehsize = ELF header size
   Write16(is64Bit() ? sizeof(ELF::Elf64_Ehdr) : sizeof(ELF::Elf32_Ehdr));
@@ -470,12 +424,12 @@ void ELFObjectWriter::WriteHeader(uint64_t SectionDataSize,
 
   // e_shnum     = # of section header ents
   if (NumberOfSections >= ELF::SHN_LORESERVE)
-    Write16(0);
+    Write16(ELF::SHN_UNDEF);
   else
     Write16(NumberOfSections);
 
   // e_shstrndx  = Section # of '.shstrtab'
-  if (NumberOfSections >= ELF::SHN_LORESERVE)
+  if (ShstrtabIndex >= ELF::SHN_LORESERVE)
     Write16(ELF::SHN_XINDEX);
   else
     Write16(ShstrtabIndex);
@@ -515,7 +469,8 @@ void ELFObjectWriter::WriteSymbolEntry(MCDataFragment *SymtabF,
   }
 }
 
-static uint64_t SymbolValue(MCSymbolData &Data, const MCAsmLayout &Layout) {
+uint64_t ELFObjectWriter::SymbolValue(MCSymbolData &Data,
+                                      const MCAsmLayout &Layout) {
   if (Data.isCommon() && Data.isExternal())
     return Data.getCommonAlignment();
 
@@ -525,15 +480,20 @@ static uint64_t SymbolValue(MCSymbolData &Data, const MCAsmLayout &Layout) {
     if (const MCExpr *Value = Symbol.getVariableValue()) {
       int64_t IntValue;
       if (Value->EvaluateAsAbsolute(IntValue, Layout))
-       return (uint64_t)IntValue;
+        return (uint64_t)IntValue;
     }
   }
 
   if (!Symbol.isInSection())
     return 0;
 
-  if (Data.getFragment())
-    return Layout.getSymbolOffset(&Data);
+
+  if (Data.getFragment()) {
+    if (Data.getFlags() & ELF_Other_ThumbFunc)
+      return Layout.getSymbolOffset(&Data)+1;
+    else
+      return Layout.getSymbolOffset(&Data);
+  }
 
   return 0;
 }
@@ -561,7 +521,7 @@ void ELFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
     // Aliases defined with .symvar copy the binding from the symbol they alias.
     // This is the first place we are able to copy this information.
     it->setExternal(SD.isExternal());
-    SetBinding(*it, GetBinding(SD));
+    MCELF::SetBinding(*it, MCELF::GetBinding(SD));
 
     StringRef Rest = AliasName.substr(Pos);
     if (!Symbol.isUndefined() && !Rest.startswith("@@@"))
@@ -587,9 +547,9 @@ void ELFObjectWriter::WriteSymbol(MCDataFragment *SymtabF,
   bool IsReserved = Data.isCommon() || Data.getSymbol().isAbsolute() ||
     Data.getSymbol().isVariable();
 
-  uint8_t Binding = GetBinding(OrigData);
-  uint8_t Visibility = GetVisibility(OrigData);
-  uint8_t Type = GetType(Data);
+  uint8_t Binding = MCELF::GetBinding(OrigData);
+  uint8_t Visibility = MCELF::GetVisibility(OrigData);
+  uint8_t Type = MCELF::GetType(Data);
 
   uint8_t Info = (Binding << ELF_STB_Shift) | (Type << ELF_STT_Shift);
   uint8_t Other = Visibility;
@@ -616,7 +576,7 @@ void ELFObjectWriter::WriteSymbolTable(MCDataFragment *SymtabF,
                                        MCDataFragment *ShndxF,
                                        const MCAssembler &Asm,
                                        const MCAsmLayout &Layout,
-                                     const SectionIndexMapTy &SectionIndexMap) {
+                                    const SectionIndexMapTy &SectionIndexMap) {
   // The string table must be emitted first because we need the index
   // into the string table for all the symbol names.
   assert(StringTable.size() && "Missing string table");
@@ -641,10 +601,12 @@ void ELFObjectWriter::WriteSymbolTable(MCDataFragment *SymtabF,
     if (Section.getType() == ELF::SHT_RELA ||
         Section.getType() == ELF::SHT_REL ||
         Section.getType() == ELF::SHT_STRTAB ||
-        Section.getType() == ELF::SHT_SYMTAB)
+        Section.getType() == ELF::SHT_SYMTAB ||
+        Section.getType() == ELF::SHT_SYMTAB_SHNDX)
       continue;
     WriteSymbolEntry(SymtabF, ShndxF, 0, ELF::STT_SECTION, 0, 0,
-                     ELF::STV_DEFAULT, SectionIndexMap.lookup(&Section), false);
+                     ELF::STV_DEFAULT, SectionIndexMap.lookup(&Section),
+                     false);
     LastLocalSymbolIndex++;
   }
 
@@ -655,7 +617,7 @@ void ELFObjectWriter::WriteSymbolTable(MCDataFragment *SymtabF,
             (Data.getFlags() & ELF_STB_Weak)) &&
            "External symbol requires STB_GLOBAL or STB_WEAK flag");
     WriteSymbol(SymtabF, ShndxF, MSD, Layout);
-    if (GetBinding(Data) == ELF::STB_LOCAL)
+    if (MCELF::GetBinding(Data) == ELF::STB_LOCAL)
       LastLocalSymbolIndex++;
   }
 
@@ -663,14 +625,16 @@ void ELFObjectWriter::WriteSymbolTable(MCDataFragment *SymtabF,
     ELFSymbolData &MSD = UndefinedSymbolData[i];
     MCSymbolData &Data = *MSD.SymbolData;
     WriteSymbol(SymtabF, ShndxF, MSD, Layout);
-    if (GetBinding(Data) == ELF::STB_LOCAL)
+    if (MCELF::GetBinding(Data) == ELF::STB_LOCAL)
       LastLocalSymbolIndex++;
   }
 }
 
 const MCSymbol *ELFObjectWriter::SymbolToReloc(const MCAssembler &Asm,
                                                const MCValue &Target,
-                                               const MCFragment &F) const {
+                                               const MCFragment &F,
+                                               const MCFixup &Fixup,
+                                               bool IsPCRel) const {
   const MCSymbol &Symbol = Target.getSymA()->getSymbol();
   const MCSymbol &ASymbol = Symbol.AliasedSymbol();
   const MCSymbol *Renamed = Renames.lookup(&Symbol);
@@ -679,7 +643,7 @@ const MCSymbol *ELFObjectWriter::SymbolToReloc(const MCAssembler &Asm,
   if (ASymbol.isUndefined()) {
     if (Renamed)
       return Renamed;
-    return &ASymbol;
+    return undefinedExplicitRelSym(Target, Fixup, IsPCRel);
   }
 
   if (SD.isExternal()) {
@@ -693,7 +657,7 @@ const MCSymbol *ELFObjectWriter::SymbolToReloc(const MCAssembler &Asm,
   const SectionKind secKind = Section.getKind();
 
   if (secKind.isBSS())
-    return NULL;
+    return ExplicitRelSym(Asm, Target, F, Fixup, IsPCRel);
 
   if (secKind.isThreadLocal()) {
     if (Renamed)
@@ -714,15 +678,16 @@ const MCSymbol *ELFObjectWriter::SymbolToReloc(const MCAssembler &Asm,
     return &Symbol;
   }
 
-  if (Section.getFlags() & MCSectionELF::SHF_MERGE) {
+  if (Section.getFlags() & ELF::SHF_MERGE) {
     if (Target.getConstant() == 0)
-      return NULL;
+      return ExplicitRelSym(Asm, Target, F, Fixup, IsPCRel);
     if (Renamed)
       return Renamed;
     return &Symbol;
   }
 
-  return NULL;
+  return ExplicitRelSym(Asm, Target, F, Fixup, IsPCRel);
+
 }
 
 
@@ -741,7 +706,7 @@ void ELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
   if (!Target.isAbsolute()) {
     const MCSymbol &Symbol = Target.getSymA()->getSymbol();
     const MCSymbol &ASymbol = Symbol.AliasedSymbol();
-    RelocSymbol = SymbolToReloc(Asm, Target, *Fragment);
+    RelocSymbol = SymbolToReloc(Asm, Target, *Fragment, Fixup, IsPCRel);
 
     if (const MCSymbolRefExpr *RefB = Target.getSymB()) {
       const MCSymbol &SymbolB = RefB->getSymbol();
@@ -751,7 +716,7 @@ void ELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
       // Offset of the symbol in the section
       int64_t a = Layout.getSymbolOffset(&SDB);
 
-      // Ofeset of the relocation in the section
+      // Offset of the relocation in the section
       int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
       Value += b - a;
     }
@@ -760,10 +725,13 @@ void ELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
       MCSymbolData &SD = Asm.getSymbolData(ASymbol);
       MCFragment *F = SD.getFragment();
 
-      Index = F->getParent()->getOrdinal() + 1;
-
-      // Offset of the symbol in the section
-      Value += Layout.getSymbolOffset(&SD);
+      if (F) {
+        Index = F->getParent()->getOrdinal() + 1;
+        // Offset of the symbol in the section
+        Value += Layout.getSymbolOffset(&SD);
+      } else {
+        Index = 0;
+      }
     } else {
       if (Asm.getSymbolData(Symbol).getFlags() & ELF_Other_Weakref)
         WeakrefUsedInReloc.insert(RelocSymbol);
@@ -772,21 +740,33 @@ void ELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
       Index = -1;
     }
     Addend = Value;
-    // Compensate for the addend on i386.
-    if (is64Bit())
+    if (hasRelocationAddend())
       Value = 0;
   }
 
   FixedValue = Value;
   unsigned Type = GetRelocType(Target, Fixup, IsPCRel,
                                (RelocSymbol != 0), Addend);
-  
+  MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
+    MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
+  if (RelocNeedsGOT(Modifier))
+    NeedsGOT = true;
+
   uint64_t RelocOffset = Layout.getFragmentOffset(Fragment) +
     Fixup.getOffset();
 
+  // FIXME: no tests cover this. Is adjustFixupOffset dead code?
+  TargetObjectWriter->adjustFixupOffset(Fixup, RelocOffset);
+
   if (!hasRelocationAddend())
     Addend = 0;
-  ELFRelocationEntry ERE(RelocOffset, Index, Type, RelocSymbol, Addend);
+
+  if (is64Bit())
+    assert(isInt<64>(Addend));
+  else
+    assert(isInt<32>(Addend));
+
+  ELFRelocationEntry ERE(RelocOffset, Index, Type, RelocSymbol, Addend, Fixup);
   Relocations[Fragment->getParent()].push_back(ERE);
 }
 
@@ -798,8 +778,9 @@ ELFObjectWriter::getSymbolIndexInSymbolTable(const MCAssembler &Asm,
   return SD.getIndex();
 }
 
-static bool isInSymtab(const MCAssembler &Asm, const MCSymbolData &Data,
-                       bool Used, bool Renamed) {
+bool ELFObjectWriter::isInSymtab(const MCAssembler &Asm,
+                                 const MCSymbolData &Data,
+                                 bool Used, bool Renamed) {
   if (Data.getFlags() & ELF_Other_Weakref)
     return false;
 
@@ -815,7 +796,11 @@ static bool isInSymtab(const MCAssembler &Asm, const MCSymbolData &Data,
     return true;
 
   const MCSymbol &A = Symbol.AliasedSymbol();
-  if (!A.isVariable() && A.isUndefined() && !Data.isCommon())
+  if (Symbol.isVariable() && !A.isVariable() && A.isUndefined())
+    return false;
+
+  bool IsGlobal = MCELF::GetBinding(Data) == ELF::STB_GLOBAL;
+  if (!Symbol.isVariable() && Symbol.isUndefined() && !IsGlobal)
     return false;
 
   if (!Asm.isSymbolLinkerVisible(Symbol) && !Symbol.isUndefined())
@@ -827,8 +812,8 @@ static bool isInSymtab(const MCAssembler &Asm, const MCSymbolData &Data,
   return true;
 }
 
-static bool isLocal(const MCSymbolData &Data, bool isSignature,
-                    bool isUsedInReloc) {
+bool ELFObjectWriter::isLocal(const MCSymbolData &Data, bool isSignature,
+                              bool isUsedInReloc) {
   if (Data.isExternal())
     return false;
 
@@ -846,7 +831,8 @@ static bool isLocal(const MCSymbolData &Data, bool isSignature,
 }
 
 void ELFObjectWriter::ComputeIndexMap(MCAssembler &Asm,
-                                      SectionIndexMapTy &SectionIndexMap) {
+                                      SectionIndexMapTy &SectionIndexMap,
+                                      const RelMapTy &RelMap) {
   unsigned Index = 1;
   for (MCAssembler::iterator it = Asm.begin(),
          ie = Asm.end(); it != ie; ++it) {
@@ -861,31 +847,38 @@ void ELFObjectWriter::ComputeIndexMap(MCAssembler &Asm,
          ie = Asm.end(); it != ie; ++it) {
     const MCSectionELF &Section =
       static_cast<const MCSectionELF &>(it->getSection());
-    if (Section.getType() == ELF::SHT_GROUP)
+    if (Section.getType() == ELF::SHT_GROUP ||
+        Section.getType() == ELF::SHT_REL ||
+        Section.getType() == ELF::SHT_RELA)
       continue;
     SectionIndexMap[&Section] = Index++;
+    const MCSectionELF *RelSection = RelMap.lookup(&Section);
+    if (RelSection)
+      SectionIndexMap[RelSection] = Index++;
   }
 }
 
 void ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm,
                                       const SectionIndexMapTy &SectionIndexMap,
-                                      RevGroupMapTy RevGroupMap) {
+                                         RevGroupMapTy RevGroupMap,
+                                         unsigned NumRegularSections) {
   // FIXME: Is this the correct place to do this?
+  // FIXME: Why is an undefined reference to _GLOBAL_OFFSET_TABLE_ needed?
   if (NeedsGOT) {
     llvm::StringRef Name = "_GLOBAL_OFFSET_TABLE_";
     MCSymbol *Sym = Asm.getContext().GetOrCreateSymbol(Name);
     MCSymbolData &Data = Asm.getOrCreateSymbolData(*Sym);
     Data.setExternal(true);
-    SetBinding(Data, ELF::STB_GLOBAL);
+    MCELF::SetBinding(Data, ELF::STB_GLOBAL);
   }
 
-  // Build section lookup table.
-  int NumRegularSections = Asm.size();
-
   // Index 0 is always the empty string.
   StringMap<uint64_t> StringIndexMap;
   StringTable += '\x00';
 
+  // FIXME: We could optimize suffixes in strtab in the same way we
+  // optimize them in shstrtab.
+
   // Add the data for the symbols.
   for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
          ie = Asm.symbol_end(); it != ie; ++it) {
@@ -907,14 +900,14 @@ void ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm,
     // Undefined symbols are global, but this is the first place we
     // are able to set it.
     bool Local = isLocal(*it, isSignature, Used);
-    if (!Local && GetBinding(*it) == ELF::STB_LOCAL) {
+    if (!Local && MCELF::GetBinding(*it) == ELF::STB_LOCAL) {
       MCSymbolData &SD = Asm.getSymbolData(RefSymbol);
-      SetBinding(*it, ELF::STB_GLOBAL);
-      SetBinding(SD, ELF::STB_GLOBAL);
+      MCELF::SetBinding(*it, ELF::STB_GLOBAL);
+      MCELF::SetBinding(SD, ELF::STB_GLOBAL);
     }
 
     if (RefSymbol.isUndefined() && !Used && WeakrefUsed)
-      SetBinding(*it, ELF::STB_WEAK);
+      MCELF::SetBinding(*it, ELF::STB_WEAK);
 
     if (it->isCommon()) {
       assert(!Local);
@@ -980,13 +973,21 @@ void ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm,
     ExternalSymbolData[i].SymbolData->setIndex(Index++);
   for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i)
     UndefinedSymbolData[i].SymbolData->setIndex(Index++);
+
+  if (NumRegularSections > ELF::SHN_LORESERVE)
+    NeedsSymtabShndx = true;
 }
 
-void ELFObjectWriter::WriteRelocation(MCAssembler &Asm, MCAsmLayout &Layout,
-                                      const MCSectionData &SD) {
-  if (!Relocations[&SD].empty()) {
+void ELFObjectWriter::CreateRelocationSections(MCAssembler &Asm,
+                                               MCAsmLayout &Layout,
+                                               RelMapTy &RelMap) {
+  for (MCAssembler::const_iterator it = Asm.begin(),
+         ie = Asm.end(); it != ie; ++it) {
+    const MCSectionData &SD = *it;
+    if (Relocations[&SD].empty())
+      continue;
+
     MCContext &Ctx = Asm.getContext();
-    const MCSectionELF *RelaSection;
     const MCSectionELF &Section =
       static_cast<const MCSectionELF&>(SD.getSection());
 
@@ -1000,17 +1001,32 @@ void ELFObjectWriter::WriteRelocation(MCAssembler &Asm, MCAsmLayout &Layout,
     else
       EntrySize = is64Bit() ? sizeof(ELF::Elf64_Rel) : sizeof(ELF::Elf32_Rel);
 
-    RelaSection = Ctx.getELFSection(RelaSectionName, hasRelocationAddend() ?
-                                    ELF::SHT_RELA : ELF::SHT_REL, 0,
-                                    SectionKind::getReadOnly(),
-                                    EntrySize, "");
+    const MCSectionELF *RelaSection =
+      Ctx.getELFSection(RelaSectionName, hasRelocationAddend() ?
+                        ELF::SHT_RELA : ELF::SHT_REL, 0,
+                        SectionKind::getReadOnly(),
+                        EntrySize, "");
+    RelMap[&Section] = RelaSection;
+    Asm.getOrCreateSectionData(*RelaSection);
+  }
+}
+
+void ELFObjectWriter::WriteRelocations(MCAssembler &Asm, MCAsmLayout &Layout,
+                                       const RelMapTy &RelMap) {
+  for (MCAssembler::const_iterator it = Asm.begin(),
+         ie = Asm.end(); it != ie; ++it) {
+    const MCSectionData &SD = *it;
+    const MCSectionELF &Section =
+      static_cast<const MCSectionELF&>(SD.getSection());
 
+    const MCSectionELF *RelaSection = RelMap.lookup(&Section);
+    if (!RelaSection)
+      continue;
     MCSectionData &RelaSD = Asm.getOrCreateSectionData(*RelaSection);
     RelaSD.setAlignment(is64Bit() ? 8 : 4);
 
     MCDataFragment *F = new MCDataFragment(&RelaSD);
-
-    WriteRelocationsFragment(Asm, F, &SD);
+    WriteRelocationsFragment(Asm, F, &*it);
   }
 }
 
@@ -1036,8 +1052,10 @@ void ELFObjectWriter::WriteRelocationsFragment(const MCAssembler &Asm,
                                                MCDataFragment *F,
                                                const MCSectionData *SD) {
   std::vector<ELFRelocationEntry> &Relocs = Relocations[SD];
-  // sort by the r_offset just like gnu as does
-  array_pod_sort(Relocs.begin(), Relocs.end());
+
+  // Sort the relocation entries. Most targets just sort by r_offset, but some
+  // (e.g., MIPS) have additional constraints.
+  TargetObjectWriter->sortRelocs(Asm, Relocs);
 
   for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
     ELFRelocationEntry entry = Relocs[e - i - 1];
@@ -1050,11 +1068,19 @@ void ELFObjectWriter::WriteRelocationsFragment(const MCAssembler &Asm,
       entry.Index += LocalSymbolData.size();
     if (is64Bit()) {
       String64(*F, entry.r_offset);
+      if (TargetObjectWriter->isN64()) {
+        String32(*F, entry.Index);
 
-      struct ELF::Elf64_Rela ERE64;
-      ERE64.setSymbolAndType(entry.Index, entry.Type);
-      String64(*F, ERE64.r_info);
-
+        String8(*F, TargetObjectWriter->getRSsym(entry.Type));
+        String8(*F, TargetObjectWriter->getRType3(entry.Type));
+        String8(*F, TargetObjectWriter->getRType2(entry.Type));
+        String8(*F, TargetObjectWriter->getRType(entry.Type));
+      }
+      else {
+        struct ELF::Elf64_Rela ERE64;
+        ERE64.setSymbolAndType(entry.Index, entry.Type);
+        String64(*F, ERE64.r_info);
+      }
       if (hasRelocationAddend())
         String64(*F, entry.r_addend);
     } else {
@@ -1070,9 +1096,28 @@ void ELFObjectWriter::WriteRelocationsFragment(const MCAssembler &Asm,
   }
 }
 
+static int compareBySuffix(const void *a, const void *b) {
+  const MCSectionELF *secA = *static_cast<const MCSectionELF* const *>(a);
+  const MCSectionELF *secB = *static_cast<const MCSectionELF* const *>(b);
+  const StringRef &NameA = secA->getSectionName();
+  const StringRef &NameB = secB->getSectionName();
+  const unsigned sizeA = NameA.size();
+  const unsigned sizeB = NameB.size();
+  const unsigned len = std::min(sizeA, sizeB);
+  for (unsigned int i = 0; i < len; ++i) {
+    char ca = NameA[sizeA - i - 1];
+    char cb = NameB[sizeB - i - 1];
+    if (ca != cb)
+      return cb - ca;
+  }
+
+  return sizeB - sizeA;
+}
+
 void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm,
                                              MCAsmLayout &Layout,
-                                    const SectionIndexMapTy &SectionIndexMap) {
+                                             SectionIndexMapTy &SectionIndexMap,
+                                             const RelMapTy &RelMap) {
   MCContext &Ctx = Asm.getContext();
   MCDataFragment *F;
 
@@ -1084,7 +1129,6 @@ void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm,
                       SectionKind::getReadOnly());
   MCSectionData &ShstrtabSD = Asm.getOrCreateSectionData(*ShstrtabSection);
   ShstrtabSD.setAlignment(1);
-  ShstrtabIndex = Asm.size();
 
   const MCSectionELF *SymtabSection =
     Ctx.getELFSection(".symtab", ELF::SHT_SYMTAB, 0,
@@ -1092,7 +1136,6 @@ void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm,
                       EntrySize, "");
   MCSectionData &SymtabSD = Asm.getOrCreateSectionData(*SymtabSection);
   SymtabSD.setAlignment(is64Bit() ? 8 : 4);
-  SymbolTableIndex = Asm.size();
 
   MCSectionData *SymtabShndxSD = NULL;
 
@@ -1104,14 +1147,17 @@ void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm,
     SymtabShndxSD->setAlignment(4);
   }
 
-  const MCSection *StrtabSection;
+  const MCSectionELF *StrtabSection;
   StrtabSection = Ctx.getELFSection(".strtab", ELF::SHT_STRTAB, 0,
                                     SectionKind::getReadOnly());
   MCSectionData &StrtabSD = Asm.getOrCreateSectionData(*StrtabSection);
   StrtabSD.setAlignment(1);
-  StringTableIndex = Asm.size();
 
-  WriteRelocations(Asm, Layout);
+  ComputeIndexMap(Asm, SectionIndexMap, RelMap);
+
+  ShstrtabIndex = SectionIndexMap.lookup(ShstrtabSection);
+  SymbolTableIndex = SectionIndexMap.lookup(SymtabSection);
+  StringTableIndex = SectionIndexMap.lookup(StrtabSection);
 
   // Symbol table
   F = new MCDataFragment(&SymtabSD);
@@ -1126,6 +1172,15 @@ void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm,
 
   F = new MCDataFragment(&ShstrtabSD);
 
+  std::vector<const MCSectionELF*> Sections;
+  for (MCAssembler::const_iterator it = Asm.begin(),
+         ie = Asm.end(); it != ie; ++it) {
+    const MCSectionELF &Section =
+      static_cast<const MCSectionELF&>(it->getSection());
+    Sections.push_back(&Section);
+  }
+  array_pod_sort(Sections.begin(), Sections.end(), compareBySuffix);
+
   // Section header string table.
   //
   // The first entry of a string table holds a null character so skip
@@ -1133,22 +1188,20 @@ void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm,
   uint64_t Index = 1;
   F->getContents() += '\x00';
 
-  StringMap<uint64_t> SecStringMap;
-  for (MCAssembler::const_iterator it = Asm.begin(),
-         ie = Asm.end(); it != ie; ++it) {
-    const MCSectionELF &Section =
-      static_cast<const MCSectionELF&>(it->getSection());
-    // FIXME: We could merge suffixes like in .text and .rela.text.
+  for (unsigned int I = 0, E = Sections.size(); I != E; ++I) {
+    const MCSectionELF &Section = *Sections[I];
 
     StringRef Name = Section.getSectionName();
-    if (SecStringMap.count(Name)) {
-      SectionStringTableIndex[&Section] =  SecStringMap[Name];
-      continue;
+    if (I != 0) {
+      StringRef PreviousName = Sections[I - 1]->getSectionName();
+      if (PreviousName.endswith(Name)) {
+        SectionStringTableIndex[&Section] = Index - Name.size() - 1;
+        continue;
+      }
     }
     // Remember the index into the string table so we can write it
     // into the sh_name field of the section header table.
     SectionStringTableIndex[&Section] = Index;
-    SecStringMap[Name] = Index;
 
     Index += Name.size() + 1;
     F->getContents() += Name;
@@ -1156,41 +1209,34 @@ void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm,
   }
 }
 
-bool
-ELFObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
-                                                      const MCSymbolData &DataA,
-                                                      const MCFragment &FB,
-                                                      bool InSet,
-                                                      bool IsPCRel) const {
-  // FIXME: This is in here just to match gnu as output. If the two ends
-  // are in the same section, there is nothing that the linker can do to
-  // break it.
-  if (DataA.isExternal())
-    return false;
-
-  const MCSection &SecA = DataA.getSymbol().AliasedSymbol().getSection();
-  const MCSection &SecB = FB.getParent()->getSection();
-  // On ELF A - B is absolute if A and B are in the same section.
-  return &SecA == &SecB;
-}
+void ELFObjectWriter::CreateIndexedSections(MCAssembler &Asm,
+                                            MCAsmLayout &Layout,
+                                            GroupMapTy &GroupMap,
+                                            RevGroupMapTy &RevGroupMap,
+                                            SectionIndexMapTy &SectionIndexMap,
+                                            const RelMapTy &RelMap) {
+  // Create the .note.GNU-stack section if needed.
+  MCContext &Ctx = Asm.getContext();
+  if (Asm.getNoExecStack()) {
+    const MCSectionELF *GnuStackSection =
+      Ctx.getELFSection(".note.GNU-stack", ELF::SHT_PROGBITS, 0,
+                        SectionKind::getReadOnly());
+    Asm.getOrCreateSectionData(*GnuStackSection);
+  }
 
-void ELFObjectWriter::CreateGroupSections(MCAssembler &Asm,
-                                          MCAsmLayout &Layout,
-                                          GroupMapTy &GroupMap,
-                                          RevGroupMapTy &RevGroupMap) {
   // Build the groups
   for (MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end();
        it != ie; ++it) {
     const MCSectionELF &Section =
       static_cast<const MCSectionELF&>(it->getSection());
-    if (!(Section.getFlags() & MCSectionELF::SHF_GROUP))
+    if (!(Section.getFlags() & ELF::SHF_GROUP))
       continue;
 
     const MCSymbol *SignatureSymbol = Section.getGroup();
     Asm.getOrCreateSymbolData(*SignatureSymbol);
     const MCSectionELF *&Group = RevGroupMap[SignatureSymbol];
     if (!Group) {
-      Group = Asm.getContext().CreateELFGroupSection();
+      Group = Ctx.CreateELFGroupSection();
       MCSectionData &Data = Asm.getOrCreateSectionData(*Group);
       Data.setAlignment(4);
       MCDataFragment *F = new MCDataFragment(&Data);
@@ -1199,20 +1245,21 @@ void ELFObjectWriter::CreateGroupSections(MCAssembler &Asm,
     GroupMap[Group] = SignatureSymbol;
   }
 
+  ComputeIndexMap(Asm, SectionIndexMap, RelMap);
+
   // Add sections to the groups
-  unsigned Index = 1;
-  unsigned NumGroups = RevGroupMap.size();
   for (MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end();
-       it != ie; ++it, ++Index) {
+       it != ie; ++it) {
     const MCSectionELF &Section =
       static_cast<const MCSectionELF&>(it->getSection());
-    if (!(Section.getFlags() & MCSectionELF::SHF_GROUP))
+    if (!(Section.getFlags() & ELF::SHF_GROUP))
       continue;
     const MCSectionELF *Group = RevGroupMap[Section.getGroup()];
     MCSectionData &Data = Asm.getOrCreateSectionData(*Group);
     // FIXME: we could use the previous fragment
     MCDataFragment *F = new MCDataFragment(&Data);
-    String32(*F, NumGroups + Index);
+    unsigned Index = SectionIndexMap.lookup(&Section);
+    String32(*F, Index);
   }
 }
 
@@ -1271,14 +1318,14 @@ void ELFObjectWriter::WriteSection(MCAssembler &Asm,
   case ELF::SHT_INIT_ARRAY:
   case ELF::SHT_FINI_ARRAY:
   case ELF::SHT_PREINIT_ARRAY:
+  case ELF::SHT_X86_64_UNWIND:
     // Nothing to do.
     break;
 
-  case ELF::SHT_GROUP: {
+  case ELF::SHT_GROUP:
     sh_link = SymbolTableIndex;
     sh_info = GroupSymbolIndex;
     break;
-  }
 
   default:
     assert(0 && "FIXME: sh_type value not supported!");
@@ -1290,12 +1337,12 @@ void ELFObjectWriter::WriteSection(MCAssembler &Asm,
                    Alignment, Section.getEntrySize());
 }
 
-static bool IsELFMetaDataSection(const MCSectionData &SD) {
+bool ELFObjectWriter::IsELFMetaDataSection(const MCSectionData &SD) {
   return SD.getOrdinal() == ~UINT32_C(0) &&
     !SD.getSection().isVirtualSection();
 }
 
-static uint64_t DataSectionSize(const MCSectionData &SD) {
+uint64_t ELFObjectWriter::DataSectionSize(const MCSectionData &SD) {
   uint64_t Ret = 0;
   for (MCSectionData::const_iterator i = SD.begin(), e = SD.end(); i != e;
        ++i) {
@@ -1306,112 +1353,56 @@ static uint64_t DataSectionSize(const MCSectionData &SD) {
   return Ret;
 }
 
-static uint64_t GetSectionFileSize(const MCAsmLayout &Layout,
-                                   const MCSectionData &SD) {
+uint64_t ELFObjectWriter::GetSectionFileSize(const MCAsmLayout &Layout,
+                                             const MCSectionData &SD) {
   if (IsELFMetaDataSection(SD))
     return DataSectionSize(SD);
   return Layout.getSectionFileSize(&SD);
 }
 
-static uint64_t GetSectionAddressSize(const MCAsmLayout &Layout,
-                                      const MCSectionData &SD) {
+uint64_t ELFObjectWriter::GetSectionAddressSize(const MCAsmLayout &Layout,
+                                                const MCSectionData &SD) {
   if (IsELFMetaDataSection(SD))
     return DataSectionSize(SD);
   return Layout.getSectionAddressSize(&SD);
 }
 
-static void WriteDataSectionData(ELFObjectWriter *W, const MCSectionData &SD) {
-  for (MCSectionData::const_iterator i = SD.begin(), e = SD.end(); i != e;
-       ++i) {
-    const MCFragment &F = *i;
-    assert(F.getKind() == MCFragment::FT_Data);
-    W->WriteBytes(cast<MCDataFragment>(F).getContents().str());
-  }
-}
-
-void ELFObjectWriter::WriteObject(MCAssembler &Asm,
-                                  const MCAsmLayout &Layout) {
-  GroupMapTy GroupMap;
-  RevGroupMapTy RevGroupMap;
-  CreateGroupSections(Asm, const_cast<MCAsmLayout&>(Layout), GroupMap,
-                      RevGroupMap);
-
-  SectionIndexMapTy SectionIndexMap;
-
-  ComputeIndexMap(Asm, SectionIndexMap);
-
-  // Compute symbol table information.
-  ComputeSymbolTable(Asm, SectionIndexMap, RevGroupMap);
+void ELFObjectWriter::WriteDataSectionData(MCAssembler &Asm,
+                                           const MCAsmLayout &Layout,
+                                           const MCSectionELF &Section) {
+  const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
 
-  CreateMetadataSections(const_cast<MCAssembler&>(Asm),
-                         const_cast<MCAsmLayout&>(Layout),
-                         SectionIndexMap);
+  uint64_t Padding = OffsetToAlignment(OS.tell(), SD.getAlignment());
+  WriteZeros(Padding);
 
-  // Update to include the metadata sections.
-  ComputeIndexMap(Asm, SectionIndexMap);
+  if (IsELFMetaDataSection(SD)) {
+    for (MCSectionData::const_iterator i = SD.begin(), e = SD.end(); i != e;
+         ++i) {
+      const MCFragment &F = *i;
+      assert(F.getKind() == MCFragment::FT_Data);
+      WriteBytes(cast<MCDataFragment>(F).getContents().str());
+    }
+  } else {
+    Asm.writeSectionData(&SD, Layout);
+  }
+}
 
-  // Add 1 for the null section.
-  unsigned NumSections = Asm.size() + 1;
-  uint64_t NaturalAlignment = is64Bit() ? 8 : 4;
-  uint64_t HeaderSize = is64Bit() ? sizeof(ELF::Elf64_Ehdr) :
-                                    sizeof(ELF::Elf32_Ehdr);
-  uint64_t FileOff = HeaderSize;
+void ELFObjectWriter::WriteSectionHeader(MCAssembler &Asm,
+                                         const GroupMapTy &GroupMap,
+                                         const MCAsmLayout &Layout,
+                                      const SectionIndexMapTy &SectionIndexMap,
+                                   const SectionOffsetMapTy &SectionOffsetMap) {
+  const unsigned NumSections = Asm.size() + 1;
 
   std::vector<const MCSectionELF*> Sections;
-  Sections.resize(NumSections);
+  Sections.resize(NumSections - 1);
 
   for (SectionIndexMapTy::const_iterator i=
          SectionIndexMap.begin(), e = SectionIndexMap.end(); i != e; ++i) {
     const std::pair<const MCSectionELF*, uint32_t> &p = *i;
-    Sections[p.second] = p.first;
+    Sections[p.second - 1] = p.first;
   }
 
-  for (unsigned i = 1; i < NumSections; ++i) {
-    const MCSectionELF &Section = *Sections[i];
-    const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
-
-    FileOff = RoundUpToAlignment(FileOff, SD.getAlignment());
-
-    // Get the size of the section in the output file (including padding).
-    FileOff += GetSectionFileSize(Layout, SD);
-  }
-
-  FileOff = RoundUpToAlignment(FileOff, NaturalAlignment);
-
-  // Write out the ELF header ...
-  WriteHeader(FileOff - HeaderSize, NumSections);
-
-  FileOff = HeaderSize;
-
-  // ... then all of the sections ...
-  DenseMap<const MCSection*, uint64_t> SectionOffsetMap;
-
-  for (unsigned i = 1; i < NumSections; ++i) {
-    const MCSectionELF &Section = *Sections[i];
-    const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
-
-    uint64_t Padding = OffsetToAlignment(FileOff, SD.getAlignment());
-    WriteZeros(Padding);
-    FileOff += Padding;
-
-    // Remember the offset into the file for this section.
-    SectionOffsetMap[&Section] = FileOff;
-
-    FileOff += GetSectionFileSize(Layout, SD);
-
-    if (IsELFMetaDataSection(SD))
-      WriteDataSectionData(this, SD);
-    else
-      Asm.WriteSectionData(&SD, Layout);
-  }
-
-  uint64_t Padding = OffsetToAlignment(FileOff, NaturalAlignment);
-  WriteZeros(Padding);
-  FileOff += Padding;
-
-  // ... and then the section header table.
-  // Should we align the section header table?
-  //
   // Null section first.
   uint64_t FirstSectionSize =
     NumSections >= ELF::SHN_LORESERVE ? NumSections : 0;
@@ -1419,362 +1410,161 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm,
     ShstrtabIndex >= ELF::SHN_LORESERVE ? ShstrtabIndex : 0;
   WriteSecHdrEntry(0, 0, 0, 0, 0, FirstSectionSize, FirstSectionLink, 0, 0, 0);
 
-  for (unsigned i = 1; i < NumSections; ++i) {
+  for (unsigned i = 0; i < NumSections - 1; ++i) {
     const MCSectionELF &Section = *Sections[i];
     const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
     uint32_t GroupSymbolIndex;
     if (Section.getType() != ELF::SHT_GROUP)
       GroupSymbolIndex = 0;
     else
-      GroupSymbolIndex = getSymbolIndexInSymbolTable(Asm, GroupMap[&Section]);
+      GroupSymbolIndex = getSymbolIndexInSymbolTable(Asm,
+                                                     GroupMap.lookup(&Section));
 
     uint64_t Size = GetSectionAddressSize(Layout, SD);
 
     WriteSection(Asm, SectionIndexMap, GroupSymbolIndex,
-                 SectionOffsetMap[&Section], Size,
+                 SectionOffsetMap.lookup(&Section), Size,
                  SD.getAlignment(), Section);
   }
 }
 
-MCObjectWriter *llvm::createELFObjectWriter(MCELFObjectTargetWriter *MOTW,
-                                            raw_ostream &OS,
-                                            bool IsLittleEndian) {
-  switch (MOTW->getEMachine()) {
-    case ELF::EM_386:
-    case ELF::EM_X86_64:
-      return new X86ELFObjectWriter(MOTW, OS, IsLittleEndian); break;
-    case ELF::EM_ARM:
-      return new ARMELFObjectWriter(MOTW, OS, IsLittleEndian); break;
-    case ELF::EM_MBLAZE:
-      return new MBlazeELFObjectWriter(MOTW, OS, IsLittleEndian); break;
-    default: llvm_unreachable("Unsupported architecture"); break;
+void ELFObjectWriter::ComputeSectionOrder(MCAssembler &Asm,
+                                  std::vector<const MCSectionELF*> &Sections) {
+  for (MCAssembler::iterator it = Asm.begin(),
+         ie = Asm.end(); it != ie; ++it) {
+    const MCSectionELF &Section =
+      static_cast<const MCSectionELF &>(it->getSection());
+    if (Section.getType() == ELF::SHT_GROUP)
+      Sections.push_back(&Section);
+  }
+
+  for (MCAssembler::iterator it = Asm.begin(),
+         ie = Asm.end(); it != ie; ++it) {
+    const MCSectionELF &Section =
+      static_cast<const MCSectionELF &>(it->getSection());
+    if (Section.getType() != ELF::SHT_GROUP &&
+        Section.getType() != ELF::SHT_REL &&
+        Section.getType() != ELF::SHT_RELA)
+      Sections.push_back(&Section);
+  }
+
+  for (MCAssembler::iterator it = Asm.begin(),
+         ie = Asm.end(); it != ie; ++it) {
+    const MCSectionELF &Section =
+      static_cast<const MCSectionELF &>(it->getSection());
+    if (Section.getType() == ELF::SHT_REL ||
+        Section.getType() == ELF::SHT_RELA)
+      Sections.push_back(&Section);
   }
 }
 
+void ELFObjectWriter::WriteObject(MCAssembler &Asm,
+                                  const MCAsmLayout &Layout) {
+  GroupMapTy GroupMap;
+  RevGroupMapTy RevGroupMap;
+  SectionIndexMapTy SectionIndexMap;
 
-/// START OF SUBCLASSES for ELFObjectWriter
-//===- ARMELFObjectWriter -------------------------------------------===//
+  unsigned NumUserSections = Asm.size();
 
-ARMELFObjectWriter::ARMELFObjectWriter(MCELFObjectTargetWriter *MOTW,
-                                       raw_ostream &_OS,
-                                       bool IsLittleEndian)
-  : ELFObjectWriter(MOTW, _OS, IsLittleEndian)
-{}
+  DenseMap<const MCSectionELF*, const MCSectionELF*> RelMap;
+  CreateRelocationSections(Asm, const_cast<MCAsmLayout&>(Layout), RelMap);
 
-ARMELFObjectWriter::~ARMELFObjectWriter()
-{}
+  const unsigned NumUserAndRelocSections = Asm.size();
+  CreateIndexedSections(Asm, const_cast<MCAsmLayout&>(Layout), GroupMap,
+                        RevGroupMap, SectionIndexMap, RelMap);
+  const unsigned AllSections = Asm.size();
+  const unsigned NumIndexedSections = AllSections - NumUserAndRelocSections;
 
-unsigned ARMELFObjectWriter::GetRelocType(const MCValue &Target,
-                                          const MCFixup &Fixup,
-                                          bool IsPCRel,
-                                          bool IsRelocWithSymbol,
-                                          int64_t Addend) {
-  MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
-    MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
+  unsigned NumRegularSections = NumUserSections + NumIndexedSections;
 
-  unsigned Type = 0;
-  if (IsPCRel) {
-    switch ((unsigned)Fixup.getKind()) {
-    default: assert(0 && "Unimplemented");
-    case FK_Data_4:
-      switch (Modifier) {
-      default: llvm_unreachable("Unsupported Modifier");
-      case MCSymbolRefExpr::VK_None:
-        Type = ELF::R_ARM_BASE_PREL;
-        break;
-      case MCSymbolRefExpr::VK_ARM_TLSGD:
-        assert(0 && "unimplemented");
-        break;
-      case MCSymbolRefExpr::VK_ARM_GOTTPOFF:
-        Type = ELF::R_ARM_TLS_IE32;
-        break;
-      }
-      break;
-    case ARM::fixup_arm_branch:
-      switch (Modifier) {
-      case MCSymbolRefExpr::VK_ARM_PLT:
-        Type = ELF::R_ARM_PLT32;
-        break;
-      default:
-        Type = ELF::R_ARM_CALL;
-        break;
-      }
-      break;
-    case ARM::fixup_arm_movt_hi16:
-    case ARM::fixup_arm_movt_hi16_pcrel:
-      Type = ELF::R_ARM_MOVT_PREL;
-      break;
-    case ARM::fixup_arm_movw_lo16:
-    case ARM::fixup_arm_movw_lo16_pcrel:
-      Type = ELF::R_ARM_MOVW_PREL_NC;
-      break;
-    }
-  } else {
-    switch ((unsigned)Fixup.getKind()) {
-    default: llvm_unreachable("invalid fixup kind!");
-    case FK_Data_4:
-      switch (Modifier) {
-      default: llvm_unreachable("Unsupported Modifier"); break;
-      case MCSymbolRefExpr::VK_ARM_GOT:
-        Type = ELF::R_ARM_GOT_BREL;
-        break;
-      case MCSymbolRefExpr::VK_ARM_TLSGD:
-        Type = ELF::R_ARM_TLS_GD32;
-        break;
-      case MCSymbolRefExpr::VK_ARM_TPOFF:
-        Type = ELF::R_ARM_TLS_LE32;
-        break;
-      case MCSymbolRefExpr::VK_ARM_GOTTPOFF:
-        Type = ELF::R_ARM_TLS_IE32;
-        break;
-      case MCSymbolRefExpr::VK_None:
-        Type = ELF::R_ARM_ABS32;
-        break;
-      case MCSymbolRefExpr::VK_ARM_GOTOFF:
-        Type = ELF::R_ARM_GOTOFF32;
-        break;
-      }
-      break;
-    case ARM::fixup_arm_ldst_pcrel_12:
-    case ARM::fixup_arm_pcrel_10:
-    case ARM::fixup_arm_adr_pcrel_12:
-    case ARM::fixup_arm_thumb_bl:
-    case ARM::fixup_arm_thumb_cb:
-    case ARM::fixup_arm_thumb_cp:
-    case ARM::fixup_arm_thumb_br:
-      assert(0 && "Unimplemented");
-      break;
-    case ARM::fixup_arm_branch:
-      // FIXME: Differentiate between R_ARM_CALL and
-      // R_ARM_JUMP24 (latter used for conditional jumps)
-      Type = ELF::R_ARM_CALL;
-      break;
-    case ARM::fixup_arm_movt_hi16:
-      Type = ELF::R_ARM_MOVT_ABS;
-      break;
-    case ARM::fixup_arm_movw_lo16:
-      Type = ELF::R_ARM_MOVW_ABS_NC;
-      break;
-    }
-  }
+  // Compute symbol table information.
+  ComputeSymbolTable(Asm, SectionIndexMap, RevGroupMap, NumRegularSections);
 
-  if (RelocNeedsGOT(Modifier))
-    NeedsGOT = true;
-  
-  return Type;
-}
 
-//===- MBlazeELFObjectWriter -------------------------------------------===//
+  WriteRelocations(Asm, const_cast<MCAsmLayout&>(Layout), RelMap);
 
-MBlazeELFObjectWriter::MBlazeELFObjectWriter(MCELFObjectTargetWriter *MOTW,
-                                             raw_ostream &_OS,
-                                             bool IsLittleEndian)
-  : ELFObjectWriter(MOTW, _OS, IsLittleEndian) {
-}
+  CreateMetadataSections(const_cast<MCAssembler&>(Asm),
+                         const_cast<MCAsmLayout&>(Layout),
+                         SectionIndexMap,
+                         RelMap);
 
-MBlazeELFObjectWriter::~MBlazeELFObjectWriter() {
-}
+  uint64_t NaturalAlignment = is64Bit() ? 8 : 4;
+  uint64_t HeaderSize = is64Bit() ? sizeof(ELF::Elf64_Ehdr) :
+                                    sizeof(ELF::Elf32_Ehdr);
+  uint64_t FileOff = HeaderSize;
 
-unsigned MBlazeELFObjectWriter::GetRelocType(const MCValue &Target,
-                                             const MCFixup &Fixup,
-                                             bool IsPCRel,
-                                             bool IsRelocWithSymbol,
-                                             int64_t Addend) {
-  // determine the type of the relocation
-  unsigned Type;
-  if (IsPCRel) {
-    switch ((unsigned)Fixup.getKind()) {
-    default:
-      llvm_unreachable("Unimplemented");
-    case FK_PCRel_4:
-      Type = ELF::R_MICROBLAZE_64_PCREL;
-      break;
-    case FK_PCRel_2:
-      Type = ELF::R_MICROBLAZE_32_PCREL;
-      break;
-    }
-  } else {
-    switch ((unsigned)Fixup.getKind()) {
-    default: llvm_unreachable("invalid fixup kind!");
-    case FK_Data_4:
-      Type = ((IsRelocWithSymbol || Addend !=0)
-              ? ELF::R_MICROBLAZE_32
-              : ELF::R_MICROBLAZE_64);
-      break;
-    case FK_Data_2:
-      Type = ELF::R_MICROBLAZE_32;
-      break;
-    }
+  std::vector<const MCSectionELF*> Sections;
+  ComputeSectionOrder(Asm, Sections);
+  unsigned NumSections = Sections.size();
+  SectionOffsetMapTy SectionOffsetMap;
+  for (unsigned i = 0; i < NumRegularSections + 1; ++i) {
+    const MCSectionELF &Section = *Sections[i];
+    const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
+
+    FileOff = RoundUpToAlignment(FileOff, SD.getAlignment());
+
+    // Remember the offset into the file for this section.
+    SectionOffsetMap[&Section] = FileOff;
+
+    // Get the size of the section in the output file (including padding).
+    FileOff += GetSectionFileSize(Layout, SD);
   }
-  return Type;
-}
 
-//===- X86ELFObjectWriter -------------------------------------------===//
+  FileOff = RoundUpToAlignment(FileOff, NaturalAlignment);
 
+  const unsigned SectionHeaderOffset = FileOff - HeaderSize;
 
-X86ELFObjectWriter::X86ELFObjectWriter(MCELFObjectTargetWriter *MOTW,
-                                       raw_ostream &_OS,
-                                       bool IsLittleEndian)
-  : ELFObjectWriter(MOTW, _OS, IsLittleEndian)
-{}
+  uint64_t SectionHeaderEntrySize = is64Bit() ?
+    sizeof(ELF::Elf64_Shdr) : sizeof(ELF::Elf32_Shdr);
+  FileOff += (NumSections + 1) * SectionHeaderEntrySize;
 
-X86ELFObjectWriter::~X86ELFObjectWriter()
-{}
+  for (unsigned i = NumRegularSections + 1; i < NumSections; ++i) {
+    const MCSectionELF &Section = *Sections[i];
+    const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
 
-unsigned X86ELFObjectWriter::GetRelocType(const MCValue &Target,
-                                          const MCFixup &Fixup,
-                                          bool IsPCRel,
-                                          bool IsRelocWithSymbol,
-                                          int64_t Addend) {
-  // determine the type of the relocation
+    FileOff = RoundUpToAlignment(FileOff, SD.getAlignment());
 
-  MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
-    MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
-  unsigned Type;
-  if (is64Bit()) {
-    if (IsPCRel) {
-      switch ((unsigned)Fixup.getKind()) {
-      default: llvm_unreachable("invalid fixup kind!");
-      case FK_PCRel_8:
-        assert(Modifier == MCSymbolRefExpr::VK_None);
-        Type = ELF::R_X86_64_PC64;
-        break;
-      case X86::reloc_signed_4byte:
-      case X86::reloc_riprel_4byte_movq_load:
-      case FK_Data_4: // FIXME?
-      case X86::reloc_riprel_4byte:
-      case FK_PCRel_4:
-        switch (Modifier) {
-        default:
-          llvm_unreachable("Unimplemented");
-        case MCSymbolRefExpr::VK_None:
-          Type = ELF::R_X86_64_PC32;
-          break;
-        case MCSymbolRefExpr::VK_PLT:
-          Type = ELF::R_X86_64_PLT32;
-          break;
-        case MCSymbolRefExpr::VK_GOTPCREL:
-          Type = ELF::R_X86_64_GOTPCREL;
-          break;
-        case MCSymbolRefExpr::VK_GOTTPOFF:
-          Type = ELF::R_X86_64_GOTTPOFF;
-        break;
-        case MCSymbolRefExpr::VK_TLSGD:
-          Type = ELF::R_X86_64_TLSGD;
-          break;
-        case MCSymbolRefExpr::VK_TLSLD:
-          Type = ELF::R_X86_64_TLSLD;
-          break;
-        }
-        break;
-      case FK_PCRel_2:
-        assert(Modifier == MCSymbolRefExpr::VK_None);
-        Type = ELF::R_X86_64_PC16;
-        break;
-      }
-    } else {
-      switch ((unsigned)Fixup.getKind()) {
-      default: llvm_unreachable("invalid fixup kind!");
-      case FK_Data_8: Type = ELF::R_X86_64_64; break;
-      case X86::reloc_signed_4byte:
-        assert(isInt<32>(Target.getConstant()));
-        switch (Modifier) {
-        default:
-          llvm_unreachable("Unimplemented");
-        case MCSymbolRefExpr::VK_None:
-          Type = ELF::R_X86_64_32S;
-          break;
-        case MCSymbolRefExpr::VK_GOT:
-          Type = ELF::R_X86_64_GOT32;
-          break;
-        case MCSymbolRefExpr::VK_GOTPCREL:
-          Type = ELF::R_X86_64_GOTPCREL;
-          break;
-        case MCSymbolRefExpr::VK_TPOFF:
-          Type = ELF::R_X86_64_TPOFF32;
-          break;
-        case MCSymbolRefExpr::VK_DTPOFF:
-          Type = ELF::R_X86_64_DTPOFF32;
-          break;
-        }
-        break;
-      case FK_Data_4:
-        Type = ELF::R_X86_64_32;
-        break;
-      case FK_Data_2: Type = ELF::R_X86_64_16; break;
-      case FK_PCRel_1:
-      case FK_Data_1: Type = ELF::R_X86_64_8; break;
-      }
-    }
-  } else {
-    if (IsPCRel) {
-      switch (Modifier) {
-      default:
-        llvm_unreachable("Unimplemented");
-      case MCSymbolRefExpr::VK_None:
-        Type = ELF::R_386_PC32;
-        break;
-      case MCSymbolRefExpr::VK_PLT:
-        Type = ELF::R_386_PLT32;
-        break;
-      }
-    } else {
-      switch ((unsigned)Fixup.getKind()) {
-      default: llvm_unreachable("invalid fixup kind!");
-
-      case X86::reloc_global_offset_table:
-        Type = ELF::R_386_GOTPC;
-        break;
-
-      // FIXME: Should we avoid selecting reloc_signed_4byte in 32 bit mode
-      // instead?
-      case X86::reloc_signed_4byte:
-      case FK_PCRel_4:
-      case FK_Data_4:
-        switch (Modifier) {
-        default:
-          llvm_unreachable("Unimplemented");
-        case MCSymbolRefExpr::VK_None:
-          Type = ELF::R_386_32;
-          break;
-        case MCSymbolRefExpr::VK_GOT:
-          Type = ELF::R_386_GOT32;
-          break;
-        case MCSymbolRefExpr::VK_GOTOFF:
-          Type = ELF::R_386_GOTOFF;
-          break;
-        case MCSymbolRefExpr::VK_TLSGD:
-          Type = ELF::R_386_TLS_GD;
-          break;
-        case MCSymbolRefExpr::VK_TPOFF:
-          Type = ELF::R_386_TLS_LE_32;
-          break;
-        case MCSymbolRefExpr::VK_INDNTPOFF:
-          Type = ELF::R_386_TLS_IE;
-          break;
-        case MCSymbolRefExpr::VK_NTPOFF:
-          Type = ELF::R_386_TLS_LE;
-          break;
-        case MCSymbolRefExpr::VK_GOTNTPOFF:
-          Type = ELF::R_386_TLS_GOTIE;
-          break;
-        case MCSymbolRefExpr::VK_TLSLDM:
-          Type = ELF::R_386_TLS_LDM;
-          break;
-        case MCSymbolRefExpr::VK_DTPOFF:
-          Type = ELF::R_386_TLS_LDO_32;
-          break;
-        }
-        break;
-      case FK_Data_2: Type = ELF::R_386_16; break;
-      case FK_PCRel_1:
-      case FK_Data_1: Type = ELF::R_386_8; break;
-      }
-    }
+    // Remember the offset into the file for this section.
+    SectionOffsetMap[&Section] = FileOff;
+
+    // Get the size of the section in the output file (including padding).
+    FileOff += GetSectionFileSize(Layout, SD);
   }
 
-  if (RelocNeedsGOT(Modifier))
-    NeedsGOT = true;
+  // Write out the ELF header ...
+  WriteHeader(SectionHeaderOffset, NumSections + 1);
+
+  // ... then the regular sections ...
+  // + because of .shstrtab
+  for (unsigned i = 0; i < NumRegularSections + 1; ++i)
+    WriteDataSectionData(Asm, Layout, *Sections[i]);
+
+  uint64_t Padding = OffsetToAlignment(OS.tell(), NaturalAlignment);
+  WriteZeros(Padding);
 
-  return Type;
+  // ... then the section header table ...
+  WriteSectionHeader(Asm, GroupMap, Layout, SectionIndexMap,
+                     SectionOffsetMap);
+
+  // ... and then the remaining sections ...
+  for (unsigned i = NumRegularSections + 1; i < NumSections; ++i)
+    WriteDataSectionData(Asm, Layout, *Sections[i]);
+}
+
+bool
+ELFObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
+                                                      const MCSymbolData &DataA,
+                                                      const MCFragment &FB,
+                                                      bool InSet,
+                                                      bool IsPCRel) const {
+  if (DataA.getFlags() & ELF_STB_Weak)
+    return false;
+  return MCObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(
+                                                 Asm, DataA, FB,InSet, IsPCRel);
+}
+
+MCObjectWriter *llvm::createELFObjectWriter(MCELFObjectTargetWriter *MOTW,
+                                            raw_ostream &OS,
+                                            bool IsLittleEndian) {
+  return new ELFObjectWriter(MOTW, OS, IsLittleEndian);
 }