llvm-6502/lib/MC/MCELFStreamer.cpp
Rafael Espindola fc5436c951 Always print the implicit .text at the start of an asm file.
Before llvm-mc would print it, but llc was assuming that it would produce
another section changing directive before one was needed. That assumption is
false with inline asm.

Fixes PR19049.

Another option would be to always create the section, but in the asm printer
avoid printing sections changes during initialization. That would work, but
* We do use the fact that llvm-mc prints it in testing. The tests can be changed
  if needed.
* A quick poll on IRC suggest that most developers prefer the implicit .text to
  be printed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203001 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-05 20:09:15 +00:00

596 lines
21 KiB
C++

//===- 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/MCAssembler.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCELF.h"
#include "llvm/MC/MCELFSymbolFlags.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCObjectStreamer.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSectionELF.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/raw_ostream.h"
using namespace llvm;
MCELFStreamer::~MCELFStreamer() {
}
void MCELFStreamer::InitSections() {
// This emulates the same behavior of GNU as. This makes it easier
// to compare the output as the major sections are in the same order.
SwitchSection(getContext().getObjectFileInfo()->getTextSection());
EmitCodeAlignment(4);
SwitchSection(getContext().getObjectFileInfo()->getDataSection());
EmitCodeAlignment(4);
SwitchSection(getContext().getObjectFileInfo()->getBSSSection());
EmitCodeAlignment(4);
SwitchSection(getContext().getObjectFileInfo()->getTextSection());
}
void MCELFStreamer::EmitLabel(MCSymbol *Symbol) {
assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
MCObjectStreamer::EmitLabel(Symbol);
const MCSectionELF &Section =
static_cast<const MCSectionELF&>(Symbol->getSection());
MCSymbolData &SD = getAssembler().getSymbolData(*Symbol);
if (Section.getFlags() & ELF::SHF_TLS)
MCELF::SetType(SD, ELF::STT_TLS);
}
void MCELFStreamer::EmitDebugLabel(MCSymbol *Symbol) {
EmitLabel(Symbol);
}
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!");
}
void MCELFStreamer::ChangeSection(const MCSection *Section,
const MCExpr *Subsection) {
MCSectionData *CurSection = getCurrentSectionData();
if (CurSection && CurSection->isBundleLocked())
report_fatal_error("Unterminated .bundle_lock when changing a section");
const MCSymbol *Grp = static_cast<const MCSectionELF *>(Section)->getGroup();
if (Grp)
getAssembler().getOrCreateSymbolData(*Grp);
this->MCObjectStreamer::ChangeSection(Section, Subsection);
}
void MCELFStreamer::EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {
getAssembler().getOrCreateSymbolData(*Symbol);
MCSymbolData &AliasSD = getAssembler().getOrCreateSymbolData(*Alias);
AliasSD.setFlags(AliasSD.getFlags() | ELF_Other_Weakref);
const MCExpr *Value = MCSymbolRefExpr::Create(Symbol, getContext());
Alias->setVariableValue(Value);
}
// 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) {
unsigned TypeOrdering[] = {ELF::STT_NOTYPE, ELF::STT_OBJECT, ELF::STT_FUNC,
ELF::STT_GNU_IFUNC, ELF::STT_TLS};
for (unsigned i = 0; i != array_lengthof(TypeOrdering); ++i) {
if (T1 == TypeOrdering[i])
return T2;
if (T2 == TypeOrdering[i])
return T1;
}
return T2;
}
bool MCELFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
MCSymbolAttr Attribute) {
// 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.SectionData = getCurrentSectionData();
getAssembler().getIndirectSymbols().push_back(ISD);
return true;
}
// Adding a symbol attribute always introduces the symbol, note that an
// important side effect of calling getOrCreateSymbolData here is to register
// the symbol with the assembler.
MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*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:
case MCSA_ELF_TypeGnuUniqueObject:
// Ignore for now.
break;
case MCSA_Global:
MCELF::SetBinding(SD, ELF::STB_GLOBAL);
SD.setExternal(true);
BindingExplicitlySet.insert(Symbol);
break;
case MCSA_WeakReference:
case MCSA_Weak:
MCELF::SetBinding(SD, ELF::STB_WEAK);
SD.setExternal(true);
BindingExplicitlySet.insert(Symbol);
break;
case MCSA_Local:
MCELF::SetBinding(SD, ELF::STB_LOCAL);
SD.setExternal(false);
BindingExplicitlySet.insert(Symbol);
break;
case MCSA_ELF_TypeFunction:
MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
ELF::STT_FUNC));
break;
case MCSA_ELF_TypeIndFunction:
MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
ELF::STT_GNU_IFUNC));
break;
case MCSA_ELF_TypeObject:
MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
ELF::STT_OBJECT));
break;
case MCSA_ELF_TypeTLS:
MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
ELF::STT_TLS));
break;
case MCSA_ELF_TypeCommon:
// TODO: Emit these as a common symbol.
MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
ELF::STT_OBJECT));
break;
case MCSA_ELF_TypeNoType:
MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
ELF::STT_NOTYPE));
break;
case MCSA_Protected:
MCELF::SetVisibility(SD, ELF::STV_PROTECTED);
break;
case MCSA_Hidden:
MCELF::SetVisibility(SD, ELF::STV_HIDDEN);
break;
case MCSA_Internal:
MCELF::SetVisibility(SD, ELF::STV_INTERNAL);
break;
}
return true;
}
void MCELFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment) {
MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
if (!BindingExplicitlySet.count(Symbol)) {
MCELF::SetBinding(SD, ELF::STB_GLOBAL);
SD.setExternal(true);
}
MCELF::SetType(SD, ELF::STT_OBJECT);
if (MCELF::GetBinding(SD) == ELF_STB_Local) {
const MCSection *Section = getAssembler().getContext().getELFSection(".bss",
ELF::SHT_NOBITS,
ELF::SHF_WRITE |
ELF::SHF_ALLOC,
SectionKind::getBSS());
AssignSection(Symbol, Section);
struct LocalCommon L = {&SD, Size, ByteAlignment};
LocalCommons.push_back(L);
} else {
SD.setCommon(Size, ByteAlignment);
}
SD.setSize(MCConstantExpr::Create(Size, getContext()));
}
void MCELFStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
SD.setSize(Value);
}
void MCELFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment) {
// FIXME: Should this be caught and done earlier?
MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
MCELF::SetBinding(SD, ELF::STB_LOCAL);
SD.setExternal(false);
BindingExplicitlySet.insert(Symbol);
EmitCommonSymbol(Symbol, Size, ByteAlignment);
}
void MCELFStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size) {
if (getCurrentSectionData()->isBundleLocked())
report_fatal_error("Emitting values inside a locked bundle is forbidden");
fixSymbolsInTLSFixups(Value);
MCObjectStreamer::EmitValueImpl(Value, Size);
}
void MCELFStreamer::EmitValueToAlignment(unsigned ByteAlignment,
int64_t Value,
unsigned ValueSize,
unsigned MaxBytesToEmit) {
if (getCurrentSectionData()->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) {
const MCSection *Comment = getAssembler().getContext().getELFSection(
".comment", ELF::SHT_PROGBITS, ELF::SHF_MERGE | ELF::SHF_STRINGS,
SectionKind::getReadOnly(), 1, "");
PushSection();
SwitchSection(Comment);
if (!SeenIdent) {
EmitIntValue(0, 1);
SeenIdent = true;
}
EmitBytes(IdentString);
EmitIntValue(0, 1);
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_DTPOFF:
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:
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:
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;
}
MCSymbolData &SD = getAssembler().getOrCreateSymbolData(symRef.getSymbol());
MCELF::SetType(SD, ELF::STT_TLS);
break;
}
case MCExpr::Unary:
fixSymbolsInTLSFixups(cast<MCUnaryExpr>(expr)->getSubExpr());
break;
}
}
void MCELFStreamer::EmitInstToFragment(const 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(const MCInst &Inst,
const MCSubtargetInfo &STI) {
MCAssembler &Assembler = getAssembler();
SmallVector<MCFixup, 4> Fixups;
SmallString<256> Code;
raw_svector_ostream VecOS(Code);
Assembler.getEmitter().EncodeInstruction(Inst, VecOS, Fixups, STI);
VecOS.flush();
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()) {
MCSectionData *SD = getCurrentSectionData();
if (SD->isBundleLocked() && !SD->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 (!SD->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 (SD->getBundleLockState() == MCSectionData::BundleLockedAlignToEnd) {
// If this is a new fragment created for a bundle-locked group, and the
// group was marked as "align_to_end", set a flag in the fragment.
DF->setAlignToBundleEnd(true);
}
}
// We're now emitting an instruction in a bundle group, so this flag has
// to be turned off.
SD->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());
}
void MCELFStreamer::EmitBundleAlignMode(unsigned AlignPow2) {
assert(AlignPow2 <= 30 && "Invalid bundle alignment");
MCAssembler &Assembler = getAssembler();
if (Assembler.getBundleAlignSize() == 0 && AlignPow2 > 0)
Assembler.setBundleAlignSize(1 << AlignPow2);
else
report_fatal_error(".bundle_align_mode should be only set once per file");
}
void MCELFStreamer::EmitBundleLock(bool AlignToEnd) {
MCSectionData *SD = getCurrentSectionData();
// Sanity checks
//
if (!getAssembler().isBundlingEnabled())
report_fatal_error(".bundle_lock forbidden when bundling is disabled");
else if (SD->isBundleLocked())
report_fatal_error("Nesting of .bundle_lock is forbidden");
SD->setBundleLockState(AlignToEnd ? MCSectionData::BundleLockedAlignToEnd :
MCSectionData::BundleLocked);
SD->setBundleGroupBeforeFirstInst(true);
}
void MCELFStreamer::EmitBundleUnlock() {
MCSectionData *SD = getCurrentSectionData();
// Sanity checks
if (!getAssembler().isBundlingEnabled())
report_fatal_error(".bundle_unlock forbidden when bundling is disabled");
else if (!SD->isBundleLocked())
report_fatal_error(".bundle_unlock without matching lock");
else if (SD->isBundleGroupBeforeFirstInst())
report_fatal_error("Empty bundle-locked group is forbidden");
SD->setBundleLockState(MCSectionData::NotBundleLocked);
}
void MCELFStreamer::Flush() {
for (std::vector<LocalCommon>::const_iterator i = LocalCommons.begin(),
e = LocalCommons.end();
i != e; ++i) {
MCSymbolData *SD = i->SD;
uint64_t Size = i->Size;
unsigned ByteAlignment = i->ByteAlignment;
const MCSymbol &Symbol = SD->getSymbol();
const MCSection &Section = Symbol.getSection();
MCSectionData &SectData = getAssembler().getOrCreateSectionData(Section);
new MCAlignFragment(ByteAlignment, 0, 1, ByteAlignment, &SectData);
MCFragment *F = new MCFillFragment(0, 0, Size, &SectData);
SD->setFragment(F);
// Update the maximum alignment of the section if necessary.
if (ByteAlignment > SectData.getAlignment())
SectData.setAlignment(ByteAlignment);
}
LocalCommons.clear();
}
void MCELFStreamer::FinishImpl() {
EmitFrames(NULL, true);
Flush();
this->MCObjectStreamer::FinishImpl();
}
MCStreamer *llvm::createELFStreamer(MCContext &Context, MCAsmBackend &MAB,
raw_ostream &OS, MCCodeEmitter *CE,
bool RelaxAll, bool NoExecStack) {
MCELFStreamer *S = new MCELFStreamer(Context, MAB, OS, CE);
if (RelaxAll)
S->getAssembler().setRelaxAll(true);
if (NoExecStack)
S->getAssembler().setNoExecStack(true);
return S;
}
void MCELFStreamer::EmitThumbFunc(MCSymbol *Func) {
llvm_unreachable("Generic ELF doesn't support this directive");
}
MCSymbolData &MCELFStreamer::getOrCreateSymbolData(MCSymbol *Symbol) {
return getAssembler().getOrCreateSymbolData(*Symbol);
}
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(const MCSection *Section, MCSymbol *Symbol,
uint64_t Size, unsigned ByteAlignment) {
llvm_unreachable("ELF doesn't support this directive");
}
void MCELFStreamer::EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
uint64_t Size, unsigned ByteAlignment) {
llvm_unreachable("ELF doesn't support this directive");
}