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Diffstat (limited to 'llvm/lib/MC/MCELFStreamer.cpp')
| -rw-r--r-- | llvm/lib/MC/MCELFStreamer.cpp | 711 |
1 files changed, 711 insertions, 0 deletions
diff --git a/llvm/lib/MC/MCELFStreamer.cpp b/llvm/lib/MC/MCELFStreamer.cpp new file mode 100644 index 0000000000000..fa2133078bfea --- /dev/null +++ b/llvm/lib/MC/MCELFStreamer.cpp @@ -0,0 +1,711 @@ +//===- lib/MC/MCELFStreamer.cpp - ELF Object Output -----------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// 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(Align(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_Cold: + 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"); + + case MCSA_LGlobal: + llvm_unreachable("ELF doesn't support the .lglobl 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(Align(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_TLSCALL: + case MCSymbolRefExpr::VK_TLSDESC: + 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_HIGH: + case MCSymbolRefExpr::VK_PPC_TPREL_HIGHA: + 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_HIGH: + case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHA: + 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()); + CEIF->setHasInstructions(STI); + 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, + SMLoc Loc) { + 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; +} |