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llvm-mirror/lib/MC/MCELFStreamer.cpp
Peter Smith 7d816e3012 [MC] Pass MCSubtargetInfo to fixupNeedsRelaxation and applyFixup 
On targets like Arm some relaxations may only be performed when certain
architectural features are available. As functions can be compiled with
differing levels of architectural support we must make a judgement on
whether we can relax based on the MCSubtargetInfo for the function. This
change passes through the MCSubtargetInfo for the function to
fixupNeedsRelaxation so that the decision on whether to relax can be made
per function. In this patch, only the ARM backend makes use of this
information. We must also pass the MCSubtargetInfo to applyFixup because
some fixups skip error checking on the assumption that relaxation has
occurred, to prevent code-generation errors applyFixup must see the same
MCSubtargetInfo as fixupNeedsRelaxation.

Differential Revision: https://reviews.llvm.org/D44928

llvm-svn: 334078
2018-06-06 09:40:06 +00:00

701 lines
24 KiB
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//===- 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/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/MC/MCAsmBackend.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/MCFixup.h"
#include "llvm/MC/MCFragment.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCSymbolELF.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#include <cstdint>
using namespace llvm;
MCELFStreamer::MCELFStreamer(MCContext &Context,
std::unique_ptr<MCAsmBackend> TAB,
std::unique_ptr<MCObjectWriter> OW,
std::unique_ptr<MCCodeEmitter> Emitter)
: MCObjectStreamer(Context, std::move(TAB), std::move(OW),
std::move(Emitter)) {}
bool MCELFStreamer::isBundleLocked() const {
return getCurrentSectionOnly()->isBundleLocked();
}
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);
EF->setBundlePadding(static_cast<uint8_t>(RequiredBundlePadding));
Assembler.writeFragmentPadding(VecOS, *EF, FSize);
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]);
}
if (DF->getSubtargetInfo() == nullptr && EF->getSubtargetInfo())
DF->setHasInstructions(*EF->getSubtargetInfo());
DF->getContents().append(EF->getContents().begin(), EF->getContents().end());
}
void MCELFStreamer::InitSections(bool NoExecStack) {
MCContext &Ctx = getContext();
SwitchSection(Ctx.getObjectFileInfo()->getTextSection());
EmitCodeAlignment(4);
if (NoExecStack)
SwitchSection(Ctx.getAsmInfo()->getNonexecutableStackSection(Ctx));
}
void MCELFStreamer::EmitLabel(MCSymbol *S, SMLoc Loc) {
auto *Symbol = cast<MCSymbolELF>(S);
MCObjectStreamer::EmitLabel(Symbol, Loc);
const MCSectionELF &Section =
static_cast<const MCSectionELF &>(*getCurrentSectionOnly());
if (Section.getFlags() & ELF::SHF_TLS)
Symbol->setType(ELF::STT_TLS);
}
void MCELFStreamer::EmitLabel(MCSymbol *S, SMLoc Loc, MCFragment *F) {
auto *Symbol = cast<MCSymbolELF>(S);
MCObjectStreamer::EmitLabel(Symbol, Loc, F);
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);
changeSectionImpl(Section, Subsection);
Asm.registerSymbol(*Section->getBeginSymbol());
}
void MCELFStreamer::EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {
getAssembler().registerSymbol(*Symbol);
const MCExpr *Value = MCSymbolRefExpr::create(
Symbol, MCSymbolRefExpr::VK_WEAKREF, 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) {
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);
// 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;
case MCSA_AltEntry:
llvm_unreachable("ELF doesn't support the .alt_entry attribute");
}
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(MCSymbol *Symbol, const MCExpr *Value) {
cast<MCSymbolELF>(Symbol)->setSize(Value);
}
void MCELFStreamer::emitELFSymverDirective(StringRef AliasName,
const MCSymbol *Aliasee) {
getAssembler().Symvers.push_back({AliasName, Aliasee});
}
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);
}
void MCELFStreamer::emitCGProfileEntry(const MCSymbolRefExpr *From,
const MCSymbolRefExpr *To,
uint64_t Count) {
getAssembler().CGProfile.push_back({From, To, Count});
}
void MCELFStreamer::EmitIdent(StringRef IdentString) {
MCSection *Comment = getAssembler().getContext().getELFSection(
".comment", ELF::SHT_PROGBITS, ELF::SHF_MERGE | ELF::SHF_STRINGS, 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_TPREL:
case MCSymbolRefExpr::VK_DTPOFF:
case MCSymbolRefExpr::VK_DTPREL:
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::finalizeCGProfileEntry(const MCSymbolRefExpr *&SRE) {
const MCSymbol *S = &SRE->getSymbol();
if (S->isTemporary()) {
if (!S->isInSection()) {
getContext().reportError(
SRE->getLoc(), Twine("Reference to undefined temporary symbol ") +
"`" + S->getName() + "`");
return;
}
S = S->getSection().getBeginSymbol();
S->setUsedInReloc();
SRE =
MCSymbolRefExpr::create(S, SRE->getKind(), getContext(), SRE->getLoc());
return;
}
// Not a temporary, referece it as a weak undefined.
bool Created;
getAssembler().registerSymbol(*S, &Created);
if (Created) {
cast<MCSymbolELF>(S)->setBinding(ELF::STB_WEAK);
cast<MCSymbolELF>(S)->setExternal(true);
}
}
void MCELFStreamer::finalizeCGProfile() {
for (MCAssembler::CGProfileEntry &E : getAssembler().CGProfile) {
finalizeCGProfileEntry(E.From);
finalizeCGProfileEntry(E.To);
}
}
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());
}
// A fragment can only have one Subtarget, and when bundling is enabled we
// sometimes need to use the same fragment. We give an error if there
// are conflicting Subtargets.
static void CheckBundleSubtargets(const MCSubtargetInfo *OldSTI,
const MCSubtargetInfo *NewSTI) {
if (OldSTI && NewSTI && OldSTI != NewSTI)
report_fatal_error("A Bundle can only have one Subtarget.");
}
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);
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, or the Subtarget has changed).
//
// 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();
CheckBundleSubtargets(DF->getSubtargetInfo(), &STI);
}
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());
CheckBundleSubtargets(DF->getSubtargetInfo(), &STI);
}
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(&STI);
}
// 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(STI);
DF->getContents().append(Code.begin(), Code.end());
if (Assembler.isBundlingEnabled() && Assembler.getRelaxAll()) {
if (!isBundleLocked()) {
mergeFragment(getOrCreateDataFragment(&STI), 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->getSubtargetInfo()), DF);
BundleGroups.pop_back();
delete DF;
}
if (Sec.getBundleLockState() != MCSection::BundleLockedAlignToEnd)
getOrCreateDataFragment()->setAlignToBundleEnd(false);
} else
Sec.setBundleLockState(MCSection::NotBundleLocked);
}
void MCELFStreamer::FinishImpl() {
// Ensure the last section gets aligned if necessary.
MCSection *CurSection = getCurrentSectionOnly();
setSectionAlignmentForBundling(getAssembler(), CurSection);
finalizeCGProfile();
EmitFrames(nullptr);
this->MCObjectStreamer::FinishImpl();
}
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::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");
}
MCStreamer *llvm::createELFStreamer(MCContext &Context,
std::unique_ptr<MCAsmBackend> &&MAB,
std::unique_ptr<MCObjectWriter> &&OW,
std::unique_ptr<MCCodeEmitter> &&CE,
bool RelaxAll) {
MCELFStreamer *S =
new MCELFStreamer(Context, std::move(MAB), std::move(OW), std::move(CE));
if (RelaxAll)
S->getAssembler().setRelaxAll(true);
return S;
}
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