//===- lib/MC/MCELFStreamer.cpp - ELF Object Output -----------------------===//

//

//                     The LLVM Compiler Infrastructure

//

// This file is distributed under the University of Illinois Open Source

// License. See LICENSE.TXT for details.

//

//===----------------------------------------------------------------------===//

//

// This file assembles .s files and emits ELF .o object files.

//

//===----------------------------------------------------------------------===//

#include "llvm/MC/MCELFStreamer.h"

#include "llvm/ADT/STLExtras.h"

#include "llvm/ADT/SmallPtrSet.h"

#include "llvm/MC/MCAsmBackend.h"

#include "llvm/MC/MCAsmLayout.h"

#include "llvm/MC/MCAsmInfo.h"

#include "llvm/MC/MCAssembler.h"

#include "llvm/MC/MCCodeEmitter.h"

#include "llvm/MC/MCContext.h"

#include "llvm/MC/MCExpr.h"

#include "llvm/MC/MCInst.h"

#include "llvm/MC/MCObjectFileInfo.h"

#include "llvm/MC/MCObjectStreamer.h"

#include "llvm/MC/MCObjectWriter.h"

#include "llvm/MC/MCSection.h"

#include "llvm/MC/MCSectionELF.h"

#include "llvm/MC/MCSymbolELF.h"

#include "llvm/MC/MCSymbol.h"

#include "llvm/MC/MCValue.h"

#include "llvm/Support/Debug.h"

#include "llvm/Support/ELF.h"

#include "llvm/Support/ErrorHandling.h"

#include "llvm/Support/TargetRegistry.h"

#include "llvm/Support/raw_ostream.h"

//#include <iostream>

using namespace llvm_ks;

bool MCELFStreamer::isBundleLocked() const {

  return getCurrentSectionOnly()->isBundleLocked();

}

MCELFStreamer::~MCELFStreamer() {

}

void MCELFStreamer::mergeFragment(MCDataFragment *DF,

                                  MCDataFragment *EF) {

  MCAssembler &Assembler = getAssembler();

  if (Assembler.isBundlingEnabled() && Assembler.getRelaxAll()) {

    uint64_t FSize = EF->getContents().size();

    if (FSize > Assembler.getBundleAlignSize())

      report_fatal_error("Fragment can't be larger than a bundle size");

    uint64_t RequiredBundlePadding = computeBundlePadding(

        Assembler, EF, DF->getContents().size(), FSize);

    if (RequiredBundlePadding > UINT8_MAX)

      report_fatal_error("Padding cannot exceed 255 bytes");

    if (RequiredBundlePadding > 0) {

      SmallString<256> Code;

      raw_svector_ostream VecOS(Code);

      MCObjectWriter *OW = Assembler.getBackend().createObjectWriter(VecOS);

      EF->setBundlePadding(static_cast<uint8_t>(RequiredBundlePadding));

      Assembler.writeFragmentPadding(*EF, FSize, OW);

      delete OW;

      DF->getContents().append(Code.begin(), Code.end());

    }

  }

  flushPendingLabels(DF, DF->getContents().size());

  for (unsigned i = 0, e = EF->getFixups().size(); i != e; ++i) {

    EF->getFixups()[i].setOffset(EF->getFixups()[i].getOffset() +

                                 DF->getContents().size());

    DF->getFixups().push_back(EF->getFixups()[i]);

  }

  DF->setHasInstructions(true);

  DF->getContents().append(EF->getContents().begin(), EF->getContents().end());

}

void MCELFStreamer::InitSections(bool NoExecStack) {

  MCContext &Ctx = getContext();

  SwitchSection(Ctx.getObjectFileInfo()->getTextSection());

  if (NoExecStack)

    SwitchSection(Ctx.getAsmInfo()->getNonexecutableStackSection(Ctx));

}

void MCELFStreamer::EmitLabel(MCSymbol *S) {

  auto *Symbol = cast<MCSymbolELF>(S);

  assert(Symbol->isUndefined() && "Cannot define a symbol twice!");

  MCObjectStreamer::EmitLabel(Symbol);

  const MCSectionELF &Section =

      static_cast<const MCSectionELF &>(*getCurrentSectionOnly());

  if (Section.getFlags() & ELF::SHF_TLS)

    Symbol->setType(ELF::STT_TLS);

}

void MCELFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {

  // Let the target do whatever target specific stuff it needs to do.

  getAssembler().getBackend().handleAssemblerFlag(Flag);

  // Do any generic stuff we need to do.

  switch (Flag) {

  case MCAF_SyntaxUnified: return; // no-op here.

  case MCAF_Code16: return; // Change parsing mode; no-op here.

  case MCAF_Code32: return; // Change parsing mode; no-op here.

  case MCAF_Code64: return; // Change parsing mode; no-op here.

  case MCAF_SubsectionsViaSymbols:

    getAssembler().setSubsectionsViaSymbols(true);

    return;

  }

  llvm_unreachable("invalid assembler flag!");

}

// If bundle alignment is used and there are any instructions in the section, it

// needs to be aligned to at least the bundle size.

static void setSectionAlignmentForBundling(const MCAssembler &Assembler,

                                           MCSection *Section) {

  if (Section && Assembler.isBundlingEnabled() && Section->hasInstructions() &&

      Section->getAlignment() < Assembler.getBundleAlignSize())

    Section->setAlignment(Assembler.getBundleAlignSize());

}

void MCELFStreamer::ChangeSection(MCSection *Section,

                                  const MCExpr *Subsection) {

  MCSection *CurSection = getCurrentSectionOnly();

  if (CurSection && isBundleLocked())

    report_fatal_error("Unterminated .bundle_lock when changing a section");

  MCAssembler &Asm = getAssembler();

  // Ensure the previous section gets aligned if necessary.

  setSectionAlignmentForBundling(Asm, CurSection);

  auto *SectionELF = static_cast<const MCSectionELF *>(Section);

  const MCSymbol *Grp = SectionELF->getGroup();

  if (Grp)

    Asm.registerSymbol(*Grp);

  this->MCObjectStreamer::ChangeSection(Section, Subsection);

  MCContext &Ctx = getContext();

  auto *Begin = cast_or_null<MCSymbolELF>(Section->getBeginSymbol());

  if (!Begin) {

    Begin = Ctx.getOrCreateSectionSymbol(*SectionELF);

    Section->setBeginSymbol(Begin);

  }

  if (Begin->isUndefined()) {

    Asm.registerSymbol(*Begin);

    Begin->setType(ELF::STT_SECTION);

  }

}

void MCELFStreamer::EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {    // qq

  getAssembler().registerSymbol(*Symbol);

  const MCExpr *Value = MCSymbolRefExpr::create(

      Symbol, MCSymbolRefExpr::VK_WEAKREF, getContext());

  bool valid;

  Alias->setVariableValue(Value, valid);

  if (!valid)

      return;

}

// When GNU as encounters more than one .type declaration for an object it seems

// to use a mechanism similar to the one below to decide which type is actually

// used in the object file.  The greater of T1 and T2 is selected based on the

// following ordering:

//  STT_NOTYPE < STT_OBJECT < STT_FUNC < STT_GNU_IFUNC < STT_TLS < anything else

// If neither T1 < T2 nor T2 < T1 according to this ordering, use T2 (the user

// provided type).

static unsigned CombineSymbolTypes(unsigned T1, unsigned T2) {

  for (unsigned Type : {ELF::STT_NOTYPE, ELF::STT_OBJECT, ELF::STT_FUNC,

                        ELF::STT_GNU_IFUNC, ELF::STT_TLS}) {

    if (T1 == Type)

      return T2;

    if (T2 == Type)

      return T1;

  }

  return T2;

}

bool MCELFStreamer::EmitSymbolAttribute(MCSymbol *S, MCSymbolAttr Attribute) {

  auto *Symbol = cast<MCSymbolELF>(S);

  // Indirect symbols are handled differently, to match how 'as' handles

  // them. This makes writing matching .o files easier.

  if (Attribute == MCSA_IndirectSymbol) {

    // Note that we intentionally cannot use the symbol data here; this is

    // important for matching the string table that 'as' generates.

    IndirectSymbolData ISD;

    ISD.Symbol = Symbol;

    ISD.Section = getCurrentSectionOnly();

    getAssembler().getIndirectSymbols().push_back(ISD);

    return true;

  }

  // Adding a symbol attribute always introduces the symbol, note that an

  // important side effect of calling registerSymbol here is to register

  // the symbol with the assembler.

  getAssembler().registerSymbol(*Symbol);

  // The implementation of symbol attributes is designed to match 'as', but it

  // leaves much to desired. It doesn't really make sense to arbitrarily add and

  // remove flags, but 'as' allows this (in particular, see .desc).

  //

  // In the future it might be worth trying to make these operations more well

  // defined.

  switch (Attribute) {

  case MCSA_LazyReference:

  case MCSA_Reference:

  case MCSA_SymbolResolver:

  case MCSA_PrivateExtern:

  case MCSA_WeakDefinition:

  case MCSA_WeakDefAutoPrivate:

  case MCSA_Invalid:

  case MCSA_IndirectSymbol:

    return false;

  case MCSA_NoDeadStrip:

    // Ignore for now.

    break;

  case MCSA_ELF_TypeGnuUniqueObject:

    Symbol->setType(CombineSymbolTypes(Symbol->getType(), ELF::STT_OBJECT));

    Symbol->setBinding(ELF::STB_GNU_UNIQUE);

    Symbol->setExternal(true);

    break;

  case MCSA_Global:

    Symbol->setBinding(ELF::STB_GLOBAL);

    Symbol->setExternal(true);

    break;

  case MCSA_WeakReference:

  case MCSA_Weak:

    Symbol->setBinding(ELF::STB_WEAK);

    Symbol->setExternal(true);

    break;

  case MCSA_Local:

    Symbol->setBinding(ELF::STB_LOCAL);

    Symbol->setExternal(false);

    break;

  case MCSA_ELF_TypeFunction:

    Symbol->setType(CombineSymbolTypes(Symbol->getType(), ELF::STT_FUNC));

    break;

  case MCSA_ELF_TypeIndFunction:

    Symbol->setType(CombineSymbolTypes(Symbol->getType(), ELF::STT_GNU_IFUNC));

    break;

  case MCSA_ELF_TypeObject:

    Symbol->setType(CombineSymbolTypes(Symbol->getType(), ELF::STT_OBJECT));

    break;

  case MCSA_ELF_TypeTLS:

    Symbol->setType(CombineSymbolTypes(Symbol->getType(), ELF::STT_TLS));

    break;

  case MCSA_ELF_TypeCommon:

    // TODO: Emit these as a common symbol.

    Symbol->setType(CombineSymbolTypes(Symbol->getType(), ELF::STT_OBJECT));

    break;

  case MCSA_ELF_TypeNoType:

    Symbol->setType(CombineSymbolTypes(Symbol->getType(), ELF::STT_NOTYPE));

    break;

  case MCSA_Protected:

    Symbol->setVisibility(ELF::STV_PROTECTED);

    break;

  case MCSA_Hidden:

    Symbol->setVisibility(ELF::STV_HIDDEN);

    break;

  case MCSA_Internal:

    Symbol->setVisibility(ELF::STV_INTERNAL);

    break;

  }

  return true;

}

void MCELFStreamer::EmitCommonSymbol(MCSymbol *S, uint64_t Size,

                                     unsigned ByteAlignment) {

  auto *Symbol = cast<MCSymbolELF>(S);

  getAssembler().registerSymbol(*Symbol);

  if (!Symbol->isBindingSet()) {

    Symbol->setBinding(ELF::STB_GLOBAL);

    Symbol->setExternal(true);

  }

  Symbol->setType(ELF::STT_OBJECT);

  if (Symbol->getBinding() == ELF::STB_LOCAL) {

    MCSection &Section = *getAssembler().getContext().getELFSection(

        ".bss", ELF::SHT_NOBITS, ELF::SHF_WRITE | ELF::SHF_ALLOC);

    MCSectionSubPair P = getCurrentSection();

    SwitchSection(&Section);

    EmitValueToAlignment(ByteAlignment, 0, 1, 0);

    EmitLabel(Symbol);

    EmitZeros(Size);

    // Update the maximum alignment of the section if necessary.

    if (ByteAlignment > Section.getAlignment())

      Section.setAlignment(ByteAlignment);

    SwitchSection(P.first, P.second);

  } else {

    if(Symbol->declareCommon(Size, ByteAlignment))

      report_fatal_error("Symbol: " + Symbol->getName() +

                         " redeclared as different type");

  }

  cast<MCSymbolELF>(Symbol)

      ->setSize(MCConstantExpr::create(Size, getContext()));

}

void MCELFStreamer::emitELFSize(MCSymbolELF *Symbol, const MCExpr *Value) {

  Symbol->setSize(Value);

}

void MCELFStreamer::EmitLocalCommonSymbol(MCSymbol *S, uint64_t Size,

                                          unsigned ByteAlignment) {

  auto *Symbol = cast<MCSymbolELF>(S);

  // FIXME: Should this be caught and done earlier?

  getAssembler().registerSymbol(*Symbol);

  Symbol->setBinding(ELF::STB_LOCAL);

  Symbol->setExternal(false);

  EmitCommonSymbol(Symbol, Size, ByteAlignment);

}

void MCELFStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,

                                  SMLoc Loc) {

  if (isBundleLocked())

    report_fatal_error("Emitting values inside a locked bundle is forbidden");

  fixSymbolsInTLSFixups(Value);

  MCObjectStreamer::EmitValueImpl(Value, Size, Loc);

}

void MCELFStreamer::EmitValueToAlignment(unsigned ByteAlignment,

                                         int64_t Value,

                                         unsigned ValueSize,

                                         unsigned MaxBytesToEmit) {

  if (isBundleLocked())

    report_fatal_error("Emitting values inside a locked bundle is forbidden");

  MCObjectStreamer::EmitValueToAlignment(ByteAlignment, Value,

                                         ValueSize, MaxBytesToEmit);

}

// Add a symbol for the file name of this module. They start after the

// null symbol and don't count as normal symbol, i.e. a non-STT_FILE symbol

// with the same name may appear.

void MCELFStreamer::EmitFileDirective(StringRef Filename) {

  getAssembler().addFileName(Filename);

}

void MCELFStreamer::EmitIdent(StringRef IdentString) {

  bool Error;

  MCSection *Comment = getAssembler().getContext().getELFSection(

      ".comment", ELF::SHT_PROGBITS, ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");

  PushSection();

  SwitchSection(Comment);

  if (!SeenIdent) {

    EmitIntValue(0, 1, Error);

    SeenIdent = true;

  }

  EmitBytes(IdentString);

  EmitIntValue(0, 1, Error);

  PopSection();

}

void MCELFStreamer::fixSymbolsInTLSFixups(const MCExpr *expr) {

  switch (expr->getKind()) {

  case MCExpr::Target:

    cast<MCTargetExpr>(expr)->fixELFSymbolsInTLSFixups(getAssembler());

    break;

  case MCExpr::Constant:

    break;

  case MCExpr::Binary: {

    const MCBinaryExpr *be = cast<MCBinaryExpr>(expr);

    fixSymbolsInTLSFixups(be->getLHS());

    fixSymbolsInTLSFixups(be->getRHS());

    break;

  }

  case MCExpr::SymbolRef: {

    const MCSymbolRefExpr &symRef = *cast<MCSymbolRefExpr>(expr);

    switch (symRef.getKind()) {

    default:

      return;

    case MCSymbolRefExpr::VK_GOTTPOFF:

    case MCSymbolRefExpr::VK_INDNTPOFF:

    case MCSymbolRefExpr::VK_NTPOFF:

    case MCSymbolRefExpr::VK_GOTNTPOFF:

    case MCSymbolRefExpr::VK_TLSGD:

    case MCSymbolRefExpr::VK_TLSLD:

    case MCSymbolRefExpr::VK_TLSLDM:

    case MCSymbolRefExpr::VK_TPOFF:

    case MCSymbolRefExpr::VK_TPREL:

    case MCSymbolRefExpr::VK_DTPOFF:

    case MCSymbolRefExpr::VK_DTPREL:

    case MCSymbolRefExpr::VK_Mips_TLSGD:

    case MCSymbolRefExpr::VK_Mips_GOTTPREL:

    case MCSymbolRefExpr::VK_Mips_TPREL_HI:

    case MCSymbolRefExpr::VK_Mips_TPREL_LO:

    case MCSymbolRefExpr::VK_PPC_DTPMOD:

    case MCSymbolRefExpr::VK_PPC_TPREL_LO:

    case MCSymbolRefExpr::VK_PPC_TPREL_HI:

    case MCSymbolRefExpr::VK_PPC_TPREL_HA:

    case MCSymbolRefExpr::VK_PPC_TPREL_HIGHER:

    case MCSymbolRefExpr::VK_PPC_TPREL_HIGHERA:

    case MCSymbolRefExpr::VK_PPC_TPREL_HIGHEST:

    case MCSymbolRefExpr::VK_PPC_TPREL_HIGHESTA:

    case MCSymbolRefExpr::VK_PPC_DTPREL_LO:

    case MCSymbolRefExpr::VK_PPC_DTPREL_HI:

    case MCSymbolRefExpr::VK_PPC_DTPREL_HA:

    case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHER:

    case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHERA:

    case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHEST:

    case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHESTA:

    case MCSymbolRefExpr::VK_PPC_GOT_TPREL:

    case MCSymbolRefExpr::VK_PPC_GOT_TPREL_LO:

    case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HI:

    case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HA:

    case MCSymbolRefExpr::VK_PPC_GOT_DTPREL:

    case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_LO:

    case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HI:

    case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HA:

    case MCSymbolRefExpr::VK_PPC_TLS:

    case MCSymbolRefExpr::VK_PPC_GOT_TLSGD:

    case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_LO:

    case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HI:

    case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HA:

    case MCSymbolRefExpr::VK_PPC_TLSGD:

    case MCSymbolRefExpr::VK_PPC_GOT_TLSLD:

    case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_LO:

    case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HI:

    case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HA:

    case MCSymbolRefExpr::VK_PPC_TLSLD:

      break;

    }

    getAssembler().registerSymbol(symRef.getSymbol());

    cast<MCSymbolELF>(symRef.getSymbol()).setType(ELF::STT_TLS);

    break;

  }

  case MCExpr::Unary:

    fixSymbolsInTLSFixups(cast<MCUnaryExpr>(expr)->getSubExpr());

    break;

  }

}

void MCELFStreamer::EmitInstToFragment(MCInst &Inst,

                                       const MCSubtargetInfo &STI) {

  this->MCObjectStreamer::EmitInstToFragment(Inst, STI);

  MCRelaxableFragment &F = *cast<MCRelaxableFragment>(getCurrentFragment());

  for (unsigned i = 0, e = F.getFixups().size(); i != e; ++i)

    fixSymbolsInTLSFixups(F.getFixups()[i].getValue());

}

void MCELFStreamer::EmitInstToData(MCInst &Inst,

                                   const MCSubtargetInfo &STI,

                                   unsigned int &KsError)

{

  MCAssembler &Assembler = getAssembler();

  SmallVector<MCFixup, 4> Fixups;

  SmallString<256> Code;

  raw_svector_ostream VecOS(Code);

  Assembler.getEmitter().encodeInstruction(Inst, VecOS, Fixups, STI, KsError);

  if (KsError)

      return;

  for (unsigned i = 0, e = Fixups.size(); i != e; ++i)

    fixSymbolsInTLSFixups(Fixups[i].getValue());

  // There are several possibilities here:

  //

  // If bundling is disabled, append the encoded instruction to the current data

  // fragment (or create a new such fragment if the current fragment is not a

  // data fragment).

  //

  // If bundling is enabled:

  // - If we're not in a bundle-locked group, emit the instruction into a

  //   fragment of its own. If there are no fixups registered for the

  //   instruction, emit a MCCompactEncodedInstFragment. Otherwise, emit a

  //   MCDataFragment.

  // - If we're in a bundle-locked group, append the instruction to the current

  //   data fragment because we want all the instructions in a group to get into

  //   the same fragment. Be careful not to do that for the first instruction in

  //   the group, though.

  MCDataFragment *DF;

  if (Assembler.isBundlingEnabled()) {

    MCSection &Sec = *getCurrentSectionOnly();

    if (Assembler.getRelaxAll() && isBundleLocked())

      // If the -mc-relax-all flag is used and we are bundle-locked, we re-use

      // the current bundle group.

      DF = BundleGroups.back();

    else if (Assembler.getRelaxAll() && !isBundleLocked())

      // When not in a bundle-locked group and the -mc-relax-all flag is used,

      // we create a new temporary fragment which will be later merged into

      // the current fragment.

      DF = new MCDataFragment();

    else if (isBundleLocked() && !Sec.isBundleGroupBeforeFirstInst())

      // If we are bundle-locked, we re-use the current fragment.

      // The bundle-locking directive ensures this is a new data fragment.

      DF = cast<MCDataFragment>(getCurrentFragment());

    else if (!isBundleLocked() && Fixups.size() == 0) {

      // Optimize memory usage by emitting the instruction to a

      // MCCompactEncodedInstFragment when not in a bundle-locked group and

      // there are no fixups registered.

      MCCompactEncodedInstFragment *CEIF = new MCCompactEncodedInstFragment();

      insert(CEIF);

      CEIF->getContents().append(Code.begin(), Code.end());

      return;

    } else {

      DF = new MCDataFragment();

      insert(DF);

    }

    if (Sec.getBundleLockState() == MCSection::BundleLockedAlignToEnd) {

      // If this fragment is for a group marked "align_to_end", set a flag

      // in the fragment. This can happen after the fragment has already been

      // created if there are nested bundle_align groups and an inner one

      // is the one marked align_to_end.

      DF->setAlignToBundleEnd(true);

    }

    // We're now emitting an instruction in a bundle group, so this flag has

    // to be turned off.

    Sec.setBundleGroupBeforeFirstInst(false);

  } else {

    DF = getOrCreateDataFragment();

  }

  // Add the fixups and data.

  for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {

    Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());

    DF->getFixups().push_back(Fixups[i]);

  }

  DF->setHasInstructions(true);

  DF->getContents().append(Code.begin(), Code.end());

  if (Assembler.isBundlingEnabled() && Assembler.getRelaxAll()) {

    if (!isBundleLocked()) {

      mergeFragment(getOrCreateDataFragment(), DF);

      delete DF;

    }

  }

}

void MCELFStreamer::EmitBundleAlignMode(unsigned AlignPow2) {

  assert(AlignPow2 <= 30 && "Invalid bundle alignment");

  MCAssembler &Assembler = getAssembler();

  if (AlignPow2 > 0 && (Assembler.getBundleAlignSize() == 0 ||

                        Assembler.getBundleAlignSize() == 1U << AlignPow2))

    Assembler.setBundleAlignSize(1U << AlignPow2);

  else

    report_fatal_error(".bundle_align_mode cannot be changed once set");

}

void MCELFStreamer::EmitBundleLock(bool AlignToEnd) {

  MCSection &Sec = *getCurrentSectionOnly();

  // Sanity checks

  //

  if (!getAssembler().isBundlingEnabled())

    report_fatal_error(".bundle_lock forbidden when bundling is disabled");

  if (!isBundleLocked())

    Sec.setBundleGroupBeforeFirstInst(true);

  if (getAssembler().getRelaxAll() && !isBundleLocked()) {

    // TODO: drop the lock state and set directly in the fragment

    MCDataFragment *DF = new MCDataFragment();

    BundleGroups.push_back(DF);

  }

  Sec.setBundleLockState(AlignToEnd ? MCSection::BundleLockedAlignToEnd

                                    : MCSection::BundleLocked);

}

void MCELFStreamer::EmitBundleUnlock() {

  MCSection &Sec = *getCurrentSectionOnly();

  // Sanity checks

  if (!getAssembler().isBundlingEnabled())

    report_fatal_error(".bundle_unlock forbidden when bundling is disabled");

  else if (!isBundleLocked())

    report_fatal_error(".bundle_unlock without matching lock");

  else if (Sec.isBundleGroupBeforeFirstInst())

    report_fatal_error("Empty bundle-locked group is forbidden");

  // When the -mc-relax-all flag is used, we emit instructions to fragments

  // stored on a stack. When the bundle unlock is emitted, we pop a fragment

  // from the stack a merge it to the one below.

  if (getAssembler().getRelaxAll()) {

    assert(!BundleGroups.empty() && "There are no bundle groups");

    MCDataFragment *DF = BundleGroups.back();

    // FIXME: Use BundleGroups to track the lock state instead.

    Sec.setBundleLockState(MCSection::NotBundleLocked);

    // FIXME: Use more separate fragments for nested groups.

    if (!isBundleLocked()) {

      mergeFragment(getOrCreateDataFragment(), DF);

      BundleGroups.pop_back();

      delete DF;

    }

    if (Sec.getBundleLockState() != MCSection::BundleLockedAlignToEnd)

      getOrCreateDataFragment()->setAlignToBundleEnd(false);

  } else

    Sec.setBundleLockState(MCSection::NotBundleLocked);

}

unsigned int MCELFStreamer::FinishImpl()

{

  // Ensure the last section gets aligned if necessary.

  MCSection *CurSection = getCurrentSectionOnly();

  setSectionAlignmentForBundling(getAssembler(), CurSection);

  EmitFrames(nullptr);

  return this->MCObjectStreamer::FinishImpl();

}

MCStreamer *llvm_ks::createELFStreamer(MCContext &Context, MCAsmBackend &MAB,

                                    raw_pwrite_stream &OS, MCCodeEmitter *CE,

                                    bool RelaxAll) {

  MCELFStreamer *S = new MCELFStreamer(Context, MAB, OS, CE);

  if (RelaxAll)

    S->getAssembler().setRelaxAll(true);

  return S;

}

void MCELFStreamer::EmitThumbFunc(MCSymbol *Func) {

  llvm_unreachable("Generic ELF doesn't support this directive");

}

void MCELFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {

  llvm_unreachable("ELF doesn't support this directive");

}

void MCELFStreamer::BeginCOFFSymbolDef(const MCSymbol *Symbol) {

  llvm_unreachable("ELF doesn't support this directive");

}

void MCELFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {

  llvm_unreachable("ELF doesn't support this directive");

}

void MCELFStreamer::EmitCOFFSymbolType(int Type) {

  llvm_unreachable("ELF doesn't support this directive");

}

void MCELFStreamer::EndCOFFSymbolDef() {

  llvm_unreachable("ELF doesn't support this directive");

}

void MCELFStreamer::EmitZerofill(MCSection *Section, MCSymbol *Symbol,

                                 uint64_t Size, unsigned ByteAlignment) {

  llvm_unreachable("ELF doesn't support this directive");

}

void MCELFStreamer::EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,

                                   uint64_t Size, unsigned ByteAlignment) {

  llvm_unreachable("ELF doesn't support this directive");

}