| //===- llvm/CodeGen/TargetLoweringObjectFileImpl.cpp - Object File Info ---===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements classes used to handle lowerings specific to common |
| // object file formats. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h" |
| #include "llvm/ADT/SmallString.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/ADT/StringExtras.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/ADT/Triple.h" |
| #include "llvm/BinaryFormat/COFF.h" |
| #include "llvm/BinaryFormat/Dwarf.h" |
| #include "llvm/BinaryFormat/ELF.h" |
| #include "llvm/BinaryFormat/MachO.h" |
| #include "llvm/CodeGen/MachineModuleInfo.h" |
| #include "llvm/CodeGen/MachineModuleInfoImpls.h" |
| #include "llvm/IR/Comdat.h" |
| #include "llvm/IR/Constants.h" |
| #include "llvm/IR/DataLayout.h" |
| #include "llvm/IR/DerivedTypes.h" |
| #include "llvm/IR/Function.h" |
| #include "llvm/IR/GlobalAlias.h" |
| #include "llvm/IR/GlobalObject.h" |
| #include "llvm/IR/GlobalValue.h" |
| #include "llvm/IR/GlobalVariable.h" |
| #include "llvm/IR/Mangler.h" |
| #include "llvm/IR/Metadata.h" |
| #include "llvm/IR/Module.h" |
| #include "llvm/IR/Type.h" |
| #include "llvm/MC/MCAsmInfo.h" |
| #include "llvm/MC/MCContext.h" |
| #include "llvm/MC/MCExpr.h" |
| #include "llvm/MC/MCSectionCOFF.h" |
| #include "llvm/MC/MCSectionELF.h" |
| #include "llvm/MC/MCSectionMachO.h" |
| #include "llvm/MC/MCSectionWasm.h" |
| #include "llvm/MC/MCStreamer.h" |
| #include "llvm/MC/MCSymbol.h" |
| #include "llvm/MC/MCSymbolELF.h" |
| #include "llvm/MC/MCValue.h" |
| #include "llvm/MC/SectionKind.h" |
| #include "llvm/ProfileData/InstrProf.h" |
| #include "llvm/Support/Casting.h" |
| #include "llvm/Support/CodeGen.h" |
| #include "llvm/Support/Format.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include "llvm/Target/TargetMachine.h" |
| #include <cassert> |
| #include <string> |
| |
| using namespace llvm; |
| using namespace dwarf; |
| |
| static void GetObjCImageInfo(Module &M, unsigned &Version, unsigned &Flags, |
| StringRef &Section) { |
| SmallVector<Module::ModuleFlagEntry, 8> ModuleFlags; |
| M.getModuleFlagsMetadata(ModuleFlags); |
| |
| for (const auto &MFE: ModuleFlags) { |
| // Ignore flags with 'Require' behaviour. |
| if (MFE.Behavior == Module::Require) |
| continue; |
| |
| StringRef Key = MFE.Key->getString(); |
| if (Key == "Objective-C Image Info Version") { |
| Version = mdconst::extract<ConstantInt>(MFE.Val)->getZExtValue(); |
| } else if (Key == "Objective-C Garbage Collection" || |
| Key == "Objective-C GC Only" || |
| Key == "Objective-C Is Simulated" || |
| Key == "Objective-C Class Properties" || |
| Key == "Objective-C Image Swift Version") { |
| Flags |= mdconst::extract<ConstantInt>(MFE.Val)->getZExtValue(); |
| } else if (Key == "Objective-C Image Info Section") { |
| Section = cast<MDString>(MFE.Val)->getString(); |
| } |
| } |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // ELF |
| //===----------------------------------------------------------------------===// |
| |
| void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx, |
| const TargetMachine &TgtM) { |
| TargetLoweringObjectFile::Initialize(Ctx, TgtM); |
| TM = &TgtM; |
| |
| CodeModel::Model CM = TgtM.getCodeModel(); |
| |
| switch (TgtM.getTargetTriple().getArch()) { |
| case Triple::arm: |
| case Triple::armeb: |
| case Triple::thumb: |
| case Triple::thumbeb: |
| if (Ctx.getAsmInfo()->getExceptionHandlingType() == ExceptionHandling::ARM) |
| break; |
| // Fallthrough if not using EHABI |
| LLVM_FALLTHROUGH; |
| case Triple::ppc: |
| case Triple::x86: |
| PersonalityEncoding = isPositionIndependent() |
| ? dwarf::DW_EH_PE_indirect | |
| dwarf::DW_EH_PE_pcrel | |
| dwarf::DW_EH_PE_sdata4 |
| : dwarf::DW_EH_PE_absptr; |
| LSDAEncoding = isPositionIndependent() |
| ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4 |
| : dwarf::DW_EH_PE_absptr; |
| TTypeEncoding = isPositionIndependent() |
| ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | |
| dwarf::DW_EH_PE_sdata4 |
| : dwarf::DW_EH_PE_absptr; |
| break; |
| case Triple::x86_64: |
| if (isPositionIndependent()) { |
| PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | |
| ((CM == CodeModel::Small || CM == CodeModel::Medium) |
| ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8); |
| LSDAEncoding = dwarf::DW_EH_PE_pcrel | |
| (CM == CodeModel::Small |
| ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8); |
| TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | |
| ((CM == CodeModel::Small || CM == CodeModel::Medium) |
| ? dwarf::DW_EH_PE_sdata8 : dwarf::DW_EH_PE_sdata4); |
| } else { |
| PersonalityEncoding = |
| (CM == CodeModel::Small || CM == CodeModel::Medium) |
| ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr; |
| LSDAEncoding = (CM == CodeModel::Small) |
| ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr; |
| TTypeEncoding = (CM == CodeModel::Small) |
| ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr; |
| } |
| break; |
| case Triple::hexagon: |
| PersonalityEncoding = dwarf::DW_EH_PE_absptr; |
| LSDAEncoding = dwarf::DW_EH_PE_absptr; |
| TTypeEncoding = dwarf::DW_EH_PE_absptr; |
| if (isPositionIndependent()) { |
| PersonalityEncoding |= dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel; |
| LSDAEncoding |= dwarf::DW_EH_PE_pcrel; |
| TTypeEncoding |= dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel; |
| } |
| break; |
| case Triple::aarch64: |
| case Triple::aarch64_be: |
| // The small model guarantees static code/data size < 4GB, but not where it |
| // will be in memory. Most of these could end up >2GB away so even a signed |
| // pc-relative 32-bit address is insufficient, theoretically. |
| if (isPositionIndependent()) { |
| PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | |
| dwarf::DW_EH_PE_sdata8; |
| LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8; |
| TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | |
| dwarf::DW_EH_PE_sdata8; |
| } else { |
| PersonalityEncoding = dwarf::DW_EH_PE_absptr; |
| LSDAEncoding = dwarf::DW_EH_PE_absptr; |
| TTypeEncoding = dwarf::DW_EH_PE_absptr; |
| } |
| break; |
| case Triple::lanai: |
| LSDAEncoding = dwarf::DW_EH_PE_absptr; |
| PersonalityEncoding = dwarf::DW_EH_PE_absptr; |
| TTypeEncoding = dwarf::DW_EH_PE_absptr; |
| break; |
| case Triple::mips: |
| case Triple::mipsel: |
| case Triple::mips64: |
| case Triple::mips64el: |
| // MIPS uses indirect pointer to refer personality functions and types, so |
| // that the eh_frame section can be read-only. DW.ref.personality will be |
| // generated for relocation. |
| PersonalityEncoding = dwarf::DW_EH_PE_indirect; |
| // FIXME: The N64 ABI probably ought to use DW_EH_PE_sdata8 but we can't |
| // identify N64 from just a triple. |
| TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | |
| dwarf::DW_EH_PE_sdata4; |
| // We don't support PC-relative LSDA references in GAS so we use the default |
| // DW_EH_PE_absptr for those. |
| |
| // FreeBSD must be explicit about the data size and using pcrel since it's |
| // assembler/linker won't do the automatic conversion that the Linux tools |
| // do. |
| if (TgtM.getTargetTriple().isOSFreeBSD()) { |
| PersonalityEncoding |= dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4; |
| LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4; |
| } |
| break; |
| case Triple::ppc64: |
| case Triple::ppc64le: |
| PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | |
| dwarf::DW_EH_PE_udata8; |
| LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8; |
| TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | |
| dwarf::DW_EH_PE_udata8; |
| break; |
| case Triple::sparcel: |
| case Triple::sparc: |
| if (isPositionIndependent()) { |
| LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4; |
| PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | |
| dwarf::DW_EH_PE_sdata4; |
| TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | |
| dwarf::DW_EH_PE_sdata4; |
| } else { |
| LSDAEncoding = dwarf::DW_EH_PE_absptr; |
| PersonalityEncoding = dwarf::DW_EH_PE_absptr; |
| TTypeEncoding = dwarf::DW_EH_PE_absptr; |
| } |
| break; |
| case Triple::sparcv9: |
| LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4; |
| if (isPositionIndependent()) { |
| PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | |
| dwarf::DW_EH_PE_sdata4; |
| TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | |
| dwarf::DW_EH_PE_sdata4; |
| } else { |
| PersonalityEncoding = dwarf::DW_EH_PE_absptr; |
| TTypeEncoding = dwarf::DW_EH_PE_absptr; |
| } |
| break; |
| case Triple::systemz: |
| // All currently-defined code models guarantee that 4-byte PC-relative |
| // values will be in range. |
| if (isPositionIndependent()) { |
| PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | |
| dwarf::DW_EH_PE_sdata4; |
| LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4; |
| TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | |
| dwarf::DW_EH_PE_sdata4; |
| } else { |
| PersonalityEncoding = dwarf::DW_EH_PE_absptr; |
| LSDAEncoding = dwarf::DW_EH_PE_absptr; |
| TTypeEncoding = dwarf::DW_EH_PE_absptr; |
| } |
| break; |
| default: |
| break; |
| } |
| } |
| |
| void TargetLoweringObjectFileELF::emitModuleMetadata(MCStreamer &Streamer, |
| Module &M) const { |
| auto &C = getContext(); |
| |
| if (NamedMDNode *LinkerOptions = M.getNamedMetadata("llvm.linker.options")) { |
| auto *S = C.getELFSection(".linker-options", ELF::SHT_LLVM_LINKER_OPTIONS, |
| ELF::SHF_EXCLUDE); |
| |
| Streamer.SwitchSection(S); |
| |
| for (const auto &Operand : LinkerOptions->operands()) { |
| if (cast<MDNode>(Operand)->getNumOperands() != 2) |
| report_fatal_error("invalid llvm.linker.options"); |
| for (const auto &Option : cast<MDNode>(Operand)->operands()) { |
| Streamer.EmitBytes(cast<MDString>(Option)->getString()); |
| Streamer.EmitIntValue(0, 1); |
| } |
| } |
| } |
| |
| unsigned Version = 0; |
| unsigned Flags = 0; |
| StringRef Section; |
| |
| GetObjCImageInfo(M, Version, Flags, Section); |
| if (!Section.empty()) { |
| auto *S = C.getELFSection(Section, ELF::SHT_PROGBITS, ELF::SHF_ALLOC); |
| Streamer.SwitchSection(S); |
| Streamer.EmitLabel(C.getOrCreateSymbol(StringRef("OBJC_IMAGE_INFO"))); |
| Streamer.EmitIntValue(Version, 4); |
| Streamer.EmitIntValue(Flags, 4); |
| Streamer.AddBlankLine(); |
| } |
| |
| SmallVector<Module::ModuleFlagEntry, 8> ModuleFlags; |
| M.getModuleFlagsMetadata(ModuleFlags); |
| |
| MDNode *CFGProfile = nullptr; |
| |
| for (const auto &MFE : ModuleFlags) { |
| StringRef Key = MFE.Key->getString(); |
| if (Key == "CG Profile") { |
| CFGProfile = cast<MDNode>(MFE.Val); |
| break; |
| } |
| } |
| |
| if (!CFGProfile) |
| return; |
| |
| auto GetSym = [this](const MDOperand &MDO) -> MCSymbol * { |
| if (!MDO) |
| return nullptr; |
| auto V = cast<ValueAsMetadata>(MDO); |
| const Function *F = cast<Function>(V->getValue()); |
| return TM->getSymbol(F); |
| }; |
| |
| for (const auto &Edge : CFGProfile->operands()) { |
| MDNode *E = cast<MDNode>(Edge); |
| const MCSymbol *From = GetSym(E->getOperand(0)); |
| const MCSymbol *To = GetSym(E->getOperand(1)); |
| // Skip null functions. This can happen if functions are dead stripped after |
| // the CGProfile pass has been run. |
| if (!From || !To) |
| continue; |
| uint64_t Count = cast<ConstantAsMetadata>(E->getOperand(2)) |
| ->getValue() |
| ->getUniqueInteger() |
| .getZExtValue(); |
| Streamer.emitCGProfileEntry( |
| MCSymbolRefExpr::create(From, MCSymbolRefExpr::VK_None, C), |
| MCSymbolRefExpr::create(To, MCSymbolRefExpr::VK_None, C), Count); |
| } |
| } |
| |
| MCSymbol *TargetLoweringObjectFileELF::getCFIPersonalitySymbol( |
| const GlobalValue *GV, const TargetMachine &TM, |
| MachineModuleInfo *MMI) const { |
| unsigned Encoding = getPersonalityEncoding(); |
| if ((Encoding & 0x80) == DW_EH_PE_indirect) |
| return getContext().getOrCreateSymbol(StringRef("DW.ref.") + |
| TM.getSymbol(GV)->getName()); |
| if ((Encoding & 0x70) == DW_EH_PE_absptr) |
| return TM.getSymbol(GV); |
| report_fatal_error("We do not support this DWARF encoding yet!"); |
| } |
| |
| void TargetLoweringObjectFileELF::emitPersonalityValue( |
| MCStreamer &Streamer, const DataLayout &DL, const MCSymbol *Sym) const { |
| SmallString<64> NameData("DW.ref."); |
| NameData += Sym->getName(); |
| MCSymbolELF *Label = |
| cast<MCSymbolELF>(getContext().getOrCreateSymbol(NameData)); |
| Streamer.EmitSymbolAttribute(Label, MCSA_Hidden); |
| Streamer.EmitSymbolAttribute(Label, MCSA_Weak); |
| unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_GROUP; |
| MCSection *Sec = getContext().getELFNamedSection(".data", Label->getName(), |
| ELF::SHT_PROGBITS, Flags, 0); |
| unsigned Size = DL.getPointerSize(); |
| Streamer.SwitchSection(Sec); |
| Streamer.EmitValueToAlignment(DL.getPointerABIAlignment(0)); |
| Streamer.EmitSymbolAttribute(Label, MCSA_ELF_TypeObject); |
| const MCExpr *E = MCConstantExpr::create(Size, getContext()); |
| Streamer.emitELFSize(Label, E); |
| Streamer.EmitLabel(Label); |
| |
| Streamer.EmitSymbolValue(Sym, Size); |
| } |
| |
| const MCExpr *TargetLoweringObjectFileELF::getTTypeGlobalReference( |
| const GlobalValue *GV, unsigned Encoding, const TargetMachine &TM, |
| MachineModuleInfo *MMI, MCStreamer &Streamer) const { |
| if (Encoding & DW_EH_PE_indirect) { |
| MachineModuleInfoELF &ELFMMI = MMI->getObjFileInfo<MachineModuleInfoELF>(); |
| |
| MCSymbol *SSym = getSymbolWithGlobalValueBase(GV, ".DW.stub", TM); |
| |
| // Add information about the stub reference to ELFMMI so that the stub |
| // gets emitted by the asmprinter. |
| MachineModuleInfoImpl::StubValueTy &StubSym = ELFMMI.getGVStubEntry(SSym); |
| if (!StubSym.getPointer()) { |
| MCSymbol *Sym = TM.getSymbol(GV); |
| StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage()); |
| } |
| |
| return TargetLoweringObjectFile:: |
| getTTypeReference(MCSymbolRefExpr::create(SSym, getContext()), |
| Encoding & ~DW_EH_PE_indirect, Streamer); |
| } |
| |
| return TargetLoweringObjectFile::getTTypeGlobalReference(GV, Encoding, TM, |
| MMI, Streamer); |
| } |
| |
| static SectionKind getELFKindForNamedSection(StringRef Name, SectionKind K) { |
| // N.B.: The defaults used in here are not the same ones used in MC. |
| // We follow gcc, MC follows gas. For example, given ".section .eh_frame", |
| // both gas and MC will produce a section with no flags. Given |
| // section(".eh_frame") gcc will produce: |
| // |
| // .section .eh_frame,"a",@progbits |
| |
| if (Name == getInstrProfSectionName(IPSK_covmap, Triple::ELF, |
| /*AddSegmentInfo=*/false)) |
| return SectionKind::getMetadata(); |
| |
| if (Name.empty() || Name[0] != '.') return K; |
| |
| // Default implementation based on some magic section names. |
| if (Name == ".bss" || |
| Name.startswith(".bss.") || |
| Name.startswith(".gnu.linkonce.b.") || |
| Name.startswith(".llvm.linkonce.b.") || |
| Name == ".sbss" || |
| Name.startswith(".sbss.") || |
| Name.startswith(".gnu.linkonce.sb.") || |
| Name.startswith(".llvm.linkonce.sb.")) |
| return SectionKind::getBSS(); |
| |
| if (Name == ".tdata" || |
| Name.startswith(".tdata.") || |
| Name.startswith(".gnu.linkonce.td.") || |
| Name.startswith(".llvm.linkonce.td.")) |
| return SectionKind::getThreadData(); |
| |
| if (Name == ".tbss" || |
| Name.startswith(".tbss.") || |
| Name.startswith(".gnu.linkonce.tb.") || |
| Name.startswith(".llvm.linkonce.tb.")) |
| return SectionKind::getThreadBSS(); |
| |
| return K; |
| } |
| |
| static unsigned getELFSectionType(StringRef Name, SectionKind K) { |
| // Use SHT_NOTE for section whose name starts with ".note" to allow |
| // emitting ELF notes from C variable declaration. |
| // See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77609 |
| if (Name.startswith(".note")) |
| return ELF::SHT_NOTE; |
| |
| if (Name == ".init_array") |
| return ELF::SHT_INIT_ARRAY; |
| |
| if (Name == ".fini_array") |
| return ELF::SHT_FINI_ARRAY; |
| |
| if (Name == ".preinit_array") |
| return ELF::SHT_PREINIT_ARRAY; |
| |
| if (K.isBSS() || K.isThreadBSS()) |
| return ELF::SHT_NOBITS; |
| |
| return ELF::SHT_PROGBITS; |
| } |
| |
| static unsigned getELFSectionFlags(SectionKind K) { |
| unsigned Flags = 0; |
| |
| if (!K.isMetadata()) |
| Flags |= ELF::SHF_ALLOC; |
| |
| if (K.isText()) |
| Flags |= ELF::SHF_EXECINSTR; |
| |
| if (K.isExecuteOnly()) |
| Flags |= ELF::SHF_ARM_PURECODE; |
| |
| if (K.isWriteable()) |
| Flags |= ELF::SHF_WRITE; |
| |
| if (K.isThreadLocal()) |
| Flags |= ELF::SHF_TLS; |
| |
| if (K.isMergeableCString() || K.isMergeableConst()) |
| Flags |= ELF::SHF_MERGE; |
| |
| if (K.isMergeableCString()) |
| Flags |= ELF::SHF_STRINGS; |
| |
| return Flags; |
| } |
| |
| static const Comdat *getELFComdat(const GlobalValue *GV) { |
| const Comdat *C = GV->getComdat(); |
| if (!C) |
| return nullptr; |
| |
| if (C->getSelectionKind() != Comdat::Any) |
| report_fatal_error("ELF COMDATs only support SelectionKind::Any, '" + |
| C->getName() + "' cannot be lowered."); |
| |
| return C; |
| } |
| |
| static const MCSymbolELF *getAssociatedSymbol(const GlobalObject *GO, |
| const TargetMachine &TM) { |
| MDNode *MD = GO->getMetadata(LLVMContext::MD_associated); |
| if (!MD) |
| return nullptr; |
| |
| const MDOperand &Op = MD->getOperand(0); |
| if (!Op.get()) |
| return nullptr; |
| |
| auto *VM = dyn_cast<ValueAsMetadata>(Op); |
| if (!VM) |
| report_fatal_error("MD_associated operand is not ValueAsMetadata"); |
| |
| GlobalObject *OtherGO = dyn_cast<GlobalObject>(VM->getValue()); |
| return OtherGO ? dyn_cast<MCSymbolELF>(TM.getSymbol(OtherGO)) : nullptr; |
| } |
| |
| static unsigned getEntrySizeForKind(SectionKind Kind) { |
| if (Kind.isMergeable1ByteCString()) |
| return 1; |
| else if (Kind.isMergeable2ByteCString()) |
| return 2; |
| else if (Kind.isMergeable4ByteCString()) |
| return 4; |
| else if (Kind.isMergeableConst4()) |
| return 4; |
| else if (Kind.isMergeableConst8()) |
| return 8; |
| else if (Kind.isMergeableConst16()) |
| return 16; |
| else if (Kind.isMergeableConst32()) |
| return 32; |
| else { |
| // We shouldn't have mergeable C strings or mergeable constants that we |
| // didn't handle above. |
| assert(!Kind.isMergeableCString() && "unknown string width"); |
| assert(!Kind.isMergeableConst() && "unknown data width"); |
| return 0; |
| } |
| } |
| |
| MCSection *TargetLoweringObjectFileELF::getExplicitSectionGlobal( |
| const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const { |
| StringRef SectionName = GO->getSection(); |
| |
| // Check if '#pragma clang section' name is applicable. |
| // Note that pragma directive overrides -ffunction-section, -fdata-section |
| // and so section name is exactly as user specified and not uniqued. |
| const GlobalVariable *GV = dyn_cast<GlobalVariable>(GO); |
| if (GV && GV->hasImplicitSection()) { |
| auto Attrs = GV->getAttributes(); |
| if (Attrs.hasAttribute("bss-section") && Kind.isBSS()) { |
| SectionName = Attrs.getAttribute("bss-section").getValueAsString(); |
| } else if (Attrs.hasAttribute("rodata-section") && Kind.isReadOnly()) { |
| SectionName = Attrs.getAttribute("rodata-section").getValueAsString(); |
| } else if (Attrs.hasAttribute("data-section") && Kind.isData()) { |
| SectionName = Attrs.getAttribute("data-section").getValueAsString(); |
| } |
| } |
| const Function *F = dyn_cast<Function>(GO); |
| if (F && F->hasFnAttribute("implicit-section-name")) { |
| SectionName = F->getFnAttribute("implicit-section-name").getValueAsString(); |
| } |
| |
| // Infer section flags from the section name if we can. |
| Kind = getELFKindForNamedSection(SectionName, Kind); |
| |
| StringRef Group = ""; |
| unsigned Flags = getELFSectionFlags(Kind); |
| if (const Comdat *C = getELFComdat(GO)) { |
| Group = C->getName(); |
| Flags |= ELF::SHF_GROUP; |
| } |
| |
| // A section can have at most one associated section. Put each global with |
| // MD_associated in a unique section. |
| unsigned UniqueID = MCContext::GenericSectionID; |
| const MCSymbolELF *AssociatedSymbol = getAssociatedSymbol(GO, TM); |
| if (AssociatedSymbol) { |
| UniqueID = NextUniqueID++; |
| Flags |= ELF::SHF_LINK_ORDER; |
| } |
| |
| MCSectionELF *Section = getContext().getELFSection( |
| SectionName, getELFSectionType(SectionName, Kind), Flags, |
| getEntrySizeForKind(Kind), Group, UniqueID, AssociatedSymbol); |
| // Make sure that we did not get some other section with incompatible sh_link. |
| // This should not be possible due to UniqueID code above. |
| assert(Section->getAssociatedSymbol() == AssociatedSymbol && |
| "Associated symbol mismatch between sections"); |
| return Section; |
| } |
| |
| /// Return the section prefix name used by options FunctionsSections and |
| /// DataSections. |
| static StringRef getSectionPrefixForGlobal(SectionKind Kind) { |
| if (Kind.isText()) |
| return ".text"; |
| if (Kind.isReadOnly()) |
| return ".rodata"; |
| if (Kind.isBSS()) |
| return ".bss"; |
| if (Kind.isThreadData()) |
| return ".tdata"; |
| if (Kind.isThreadBSS()) |
| return ".tbss"; |
| if (Kind.isData()) |
| return ".data"; |
| assert(Kind.isReadOnlyWithRel() && "Unknown section kind"); |
| return ".data.rel.ro"; |
| } |
| |
| static MCSectionELF *selectELFSectionForGlobal( |
| MCContext &Ctx, const GlobalObject *GO, SectionKind Kind, Mangler &Mang, |
| const TargetMachine &TM, bool EmitUniqueSection, unsigned Flags, |
| unsigned *NextUniqueID, const MCSymbolELF *AssociatedSymbol) { |
| |
| StringRef Group = ""; |
| if (const Comdat *C = getELFComdat(GO)) { |
| Flags |= ELF::SHF_GROUP; |
| Group = C->getName(); |
| } |
| |
| // Get the section entry size based on the kind. |
| unsigned EntrySize = getEntrySizeForKind(Kind); |
| |
| SmallString<128> Name; |
| if (Kind.isMergeableCString()) { |
| // We also need alignment here. |
| // FIXME: this is getting the alignment of the character, not the |
| // alignment of the global! |
| unsigned Align = GO->getParent()->getDataLayout().getPreferredAlignment( |
| cast<GlobalVariable>(GO)); |
| |
| std::string SizeSpec = ".rodata.str" + utostr(EntrySize) + "."; |
| Name = SizeSpec + utostr(Align); |
| } else if (Kind.isMergeableConst()) { |
| Name = ".rodata.cst"; |
| Name += utostr(EntrySize); |
| } else { |
| Name = getSectionPrefixForGlobal(Kind); |
| } |
| |
| if (const auto *F = dyn_cast<Function>(GO)) { |
| const auto &OptionalPrefix = F->getSectionPrefix(); |
| if (OptionalPrefix) |
| Name += *OptionalPrefix; |
| } |
| |
| unsigned UniqueID = MCContext::GenericSectionID; |
| if (EmitUniqueSection) { |
| if (TM.getUniqueSectionNames()) { |
| Name.push_back('.'); |
| TM.getNameWithPrefix(Name, GO, Mang, true /*MayAlwaysUsePrivate*/); |
| } else { |
| UniqueID = *NextUniqueID; |
| (*NextUniqueID)++; |
| } |
| } |
| // Use 0 as the unique ID for execute-only text. |
| if (Kind.isExecuteOnly()) |
| UniqueID = 0; |
| return Ctx.getELFSection(Name, getELFSectionType(Name, Kind), Flags, |
| EntrySize, Group, UniqueID, AssociatedSymbol); |
| } |
| |
| MCSection *TargetLoweringObjectFileELF::SelectSectionForGlobal( |
| const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const { |
| unsigned Flags = getELFSectionFlags(Kind); |
| |
| // If we have -ffunction-section or -fdata-section then we should emit the |
| // global value to a uniqued section specifically for it. |
| bool EmitUniqueSection = false; |
| if (!(Flags & ELF::SHF_MERGE) && !Kind.isCommon()) { |
| if (Kind.isText()) |
| EmitUniqueSection = TM.getFunctionSections(); |
| else |
| EmitUniqueSection = TM.getDataSections(); |
| } |
| EmitUniqueSection |= GO->hasComdat(); |
| |
| const MCSymbolELF *AssociatedSymbol = getAssociatedSymbol(GO, TM); |
| if (AssociatedSymbol) { |
| EmitUniqueSection = true; |
| Flags |= ELF::SHF_LINK_ORDER; |
| } |
| |
| MCSectionELF *Section = selectELFSectionForGlobal( |
| getContext(), GO, Kind, getMangler(), TM, EmitUniqueSection, Flags, |
| &NextUniqueID, AssociatedSymbol); |
| assert(Section->getAssociatedSymbol() == AssociatedSymbol); |
| return Section; |
| } |
| |
| MCSection *TargetLoweringObjectFileELF::getSectionForJumpTable( |
| const Function &F, const TargetMachine &TM) const { |
| // If the function can be removed, produce a unique section so that |
| // the table doesn't prevent the removal. |
| const Comdat *C = F.getComdat(); |
| bool EmitUniqueSection = TM.getFunctionSections() || C; |
| if (!EmitUniqueSection) |
| return ReadOnlySection; |
| |
| return selectELFSectionForGlobal(getContext(), &F, SectionKind::getReadOnly(), |
| getMangler(), TM, EmitUniqueSection, |
| ELF::SHF_ALLOC, &NextUniqueID, |
| /* AssociatedSymbol */ nullptr); |
| } |
| |
| bool TargetLoweringObjectFileELF::shouldPutJumpTableInFunctionSection( |
| bool UsesLabelDifference, const Function &F) const { |
| // We can always create relative relocations, so use another section |
| // that can be marked non-executable. |
| return false; |
| } |
| |
| /// Given a mergeable constant with the specified size and relocation |
| /// information, return a section that it should be placed in. |
| MCSection *TargetLoweringObjectFileELF::getSectionForConstant( |
| const DataLayout &DL, SectionKind Kind, const Constant *C, |
| unsigned &Align) const { |
| if (Kind.isMergeableConst4() && MergeableConst4Section) |
| return MergeableConst4Section; |
| if (Kind.isMergeableConst8() && MergeableConst8Section) |
| return MergeableConst8Section; |
| if (Kind.isMergeableConst16() && MergeableConst16Section) |
| return MergeableConst16Section; |
| if (Kind.isMergeableConst32() && MergeableConst32Section) |
| return MergeableConst32Section; |
| if (Kind.isReadOnly()) |
| return ReadOnlySection; |
| |
| assert(Kind.isReadOnlyWithRel() && "Unknown section kind"); |
| return DataRelROSection; |
| } |
| |
| static MCSectionELF *getStaticStructorSection(MCContext &Ctx, bool UseInitArray, |
| bool IsCtor, unsigned Priority, |
| const MCSymbol *KeySym) { |
| std::string Name; |
| unsigned Type; |
| unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE; |
| StringRef COMDAT = KeySym ? KeySym->getName() : ""; |
| |
| if (KeySym) |
| Flags |= ELF::SHF_GROUP; |
| |
| if (UseInitArray) { |
| if (IsCtor) { |
| Type = ELF::SHT_INIT_ARRAY; |
| Name = ".init_array"; |
| } else { |
| Type = ELF::SHT_FINI_ARRAY; |
| Name = ".fini_array"; |
| } |
| if (Priority != 65535) { |
| Name += '.'; |
| Name += utostr(Priority); |
| } |
| } else { |
| // The default scheme is .ctor / .dtor, so we have to invert the priority |
| // numbering. |
| if (IsCtor) |
| Name = ".ctors"; |
| else |
| Name = ".dtors"; |
| if (Priority != 65535) |
| raw_string_ostream(Name) << format(".%05u", 65535 - Priority); |
| Type = ELF::SHT_PROGBITS; |
| } |
| |
| return Ctx.getELFSection(Name, Type, Flags, 0, COMDAT); |
| } |
| |
| MCSection *TargetLoweringObjectFileELF::getStaticCtorSection( |
| unsigned Priority, const MCSymbol *KeySym) const { |
| return getStaticStructorSection(getContext(), UseInitArray, true, Priority, |
| KeySym); |
| } |
| |
| MCSection *TargetLoweringObjectFileELF::getStaticDtorSection( |
| unsigned Priority, const MCSymbol *KeySym) const { |
| return getStaticStructorSection(getContext(), UseInitArray, false, Priority, |
| KeySym); |
| } |
| |
| const MCExpr *TargetLoweringObjectFileELF::lowerRelativeReference( |
| const GlobalValue *LHS, const GlobalValue *RHS, |
| const TargetMachine &TM) const { |
| // We may only use a PLT-relative relocation to refer to unnamed_addr |
| // functions. |
| if (!LHS->hasGlobalUnnamedAddr() || !LHS->getValueType()->isFunctionTy()) |
| return nullptr; |
| |
| // Basic sanity checks. |
| if (LHS->getType()->getPointerAddressSpace() != 0 || |
| RHS->getType()->getPointerAddressSpace() != 0 || LHS->isThreadLocal() || |
| RHS->isThreadLocal()) |
| return nullptr; |
| |
| return MCBinaryExpr::createSub( |
| MCSymbolRefExpr::create(TM.getSymbol(LHS), PLTRelativeVariantKind, |
| getContext()), |
| MCSymbolRefExpr::create(TM.getSymbol(RHS), getContext()), getContext()); |
| } |
| |
| void |
| TargetLoweringObjectFileELF::InitializeELF(bool UseInitArray_) { |
| UseInitArray = UseInitArray_; |
| MCContext &Ctx = getContext(); |
| if (!UseInitArray) { |
| StaticCtorSection = Ctx.getELFSection(".ctors", ELF::SHT_PROGBITS, |
| ELF::SHF_ALLOC | ELF::SHF_WRITE); |
| |
| StaticDtorSection = Ctx.getELFSection(".dtors", ELF::SHT_PROGBITS, |
| ELF::SHF_ALLOC | ELF::SHF_WRITE); |
| return; |
| } |
| |
| StaticCtorSection = Ctx.getELFSection(".init_array", ELF::SHT_INIT_ARRAY, |
| ELF::SHF_WRITE | ELF::SHF_ALLOC); |
| StaticDtorSection = Ctx.getELFSection(".fini_array", ELF::SHT_FINI_ARRAY, |
| ELF::SHF_WRITE | ELF::SHF_ALLOC); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // MachO |
| //===----------------------------------------------------------------------===// |
| |
| TargetLoweringObjectFileMachO::TargetLoweringObjectFileMachO() |
| : TargetLoweringObjectFile() { |
| SupportIndirectSymViaGOTPCRel = true; |
| } |
| |
| void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx, |
| const TargetMachine &TM) { |
| TargetLoweringObjectFile::Initialize(Ctx, TM); |
| if (TM.getRelocationModel() == Reloc::Static) { |
| StaticCtorSection = Ctx.getMachOSection("__TEXT", "__constructor", 0, |
| SectionKind::getData()); |
| StaticDtorSection = Ctx.getMachOSection("__TEXT", "__destructor", 0, |
| SectionKind::getData()); |
| } else { |
| StaticCtorSection = Ctx.getMachOSection("__DATA", "__mod_init_func", |
| MachO::S_MOD_INIT_FUNC_POINTERS, |
| SectionKind::getData()); |
| StaticDtorSection = Ctx.getMachOSection("__DATA", "__mod_term_func", |
| MachO::S_MOD_TERM_FUNC_POINTERS, |
| SectionKind::getData()); |
| } |
| |
| PersonalityEncoding = |
| dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4; |
| LSDAEncoding = dwarf::DW_EH_PE_pcrel; |
| TTypeEncoding = |
| dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4; |
| } |
| |
| void TargetLoweringObjectFileMachO::emitModuleMetadata(MCStreamer &Streamer, |
| Module &M) const { |
| // Emit the linker options if present. |
| if (auto *LinkerOptions = M.getNamedMetadata("llvm.linker.options")) { |
| for (const auto &Option : LinkerOptions->operands()) { |
| SmallVector<std::string, 4> StrOptions; |
| for (const auto &Piece : cast<MDNode>(Option)->operands()) |
| StrOptions.push_back(cast<MDString>(Piece)->getString()); |
| Streamer.EmitLinkerOptions(StrOptions); |
| } |
| } |
| |
| unsigned VersionVal = 0; |
| unsigned ImageInfoFlags = 0; |
| StringRef SectionVal; |
| |
| GetObjCImageInfo(M, VersionVal, ImageInfoFlags, SectionVal); |
| |
| // The section is mandatory. If we don't have it, then we don't have GC info. |
| if (SectionVal.empty()) |
| return; |
| |
| StringRef Segment, Section; |
| unsigned TAA = 0, StubSize = 0; |
| bool TAAParsed; |
| std::string ErrorCode = |
| MCSectionMachO::ParseSectionSpecifier(SectionVal, Segment, Section, |
| TAA, TAAParsed, StubSize); |
| if (!ErrorCode.empty()) |
| // If invalid, report the error with report_fatal_error. |
| report_fatal_error("Invalid section specifier '" + Section + "': " + |
| ErrorCode + "."); |
| |
| // Get the section. |
| MCSectionMachO *S = getContext().getMachOSection( |
| Segment, Section, TAA, StubSize, SectionKind::getData()); |
| Streamer.SwitchSection(S); |
| Streamer.EmitLabel(getContext(). |
| getOrCreateSymbol(StringRef("L_OBJC_IMAGE_INFO"))); |
| Streamer.EmitIntValue(VersionVal, 4); |
| Streamer.EmitIntValue(ImageInfoFlags, 4); |
| Streamer.AddBlankLine(); |
| } |
| |
| static void checkMachOComdat(const GlobalValue *GV) { |
| const Comdat *C = GV->getComdat(); |
| if (!C) |
| return; |
| |
| report_fatal_error("MachO doesn't support COMDATs, '" + C->getName() + |
| "' cannot be lowered."); |
| } |
| |
| MCSection *TargetLoweringObjectFileMachO::getExplicitSectionGlobal( |
| const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const { |
| // Parse the section specifier and create it if valid. |
| StringRef Segment, Section; |
| unsigned TAA = 0, StubSize = 0; |
| bool TAAParsed; |
| |
| checkMachOComdat(GO); |
| |
| std::string ErrorCode = |
| MCSectionMachO::ParseSectionSpecifier(GO->getSection(), Segment, Section, |
| TAA, TAAParsed, StubSize); |
| if (!ErrorCode.empty()) { |
| // If invalid, report the error with report_fatal_error. |
| report_fatal_error("Global variable '" + GO->getName() + |
| "' has an invalid section specifier '" + |
| GO->getSection() + "': " + ErrorCode + "."); |
| } |
| |
| // Get the section. |
| MCSectionMachO *S = |
| getContext().getMachOSection(Segment, Section, TAA, StubSize, Kind); |
| |
| // If TAA wasn't set by ParseSectionSpecifier() above, |
| // use the value returned by getMachOSection() as a default. |
| if (!TAAParsed) |
| TAA = S->getTypeAndAttributes(); |
| |
| // Okay, now that we got the section, verify that the TAA & StubSize agree. |
| // If the user declared multiple globals with different section flags, we need |
| // to reject it here. |
| if (S->getTypeAndAttributes() != TAA || S->getStubSize() != StubSize) { |
| // If invalid, report the error with report_fatal_error. |
| report_fatal_error("Global variable '" + GO->getName() + |
| "' section type or attributes does not match previous" |
| " section specifier"); |
| } |
| |
| return S; |
| } |
| |
| MCSection *TargetLoweringObjectFileMachO::SelectSectionForGlobal( |
| const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const { |
| checkMachOComdat(GO); |
| |
| // Handle thread local data. |
| if (Kind.isThreadBSS()) return TLSBSSSection; |
| if (Kind.isThreadData()) return TLSDataSection; |
| |
| if (Kind.isText()) |
| return GO->isWeakForLinker() ? TextCoalSection : TextSection; |
| |
| // If this is weak/linkonce, put this in a coalescable section, either in text |
| // or data depending on if it is writable. |
| if (GO->isWeakForLinker()) { |
| if (Kind.isReadOnly()) |
| return ConstTextCoalSection; |
| if (Kind.isReadOnlyWithRel()) |
| return ConstDataCoalSection; |
| return DataCoalSection; |
| } |
| |
| // FIXME: Alignment check should be handled by section classifier. |
| if (Kind.isMergeable1ByteCString() && |
| GO->getParent()->getDataLayout().getPreferredAlignment( |
| cast<GlobalVariable>(GO)) < 32) |
| return CStringSection; |
| |
| // Do not put 16-bit arrays in the UString section if they have an |
| // externally visible label, this runs into issues with certain linker |
| // versions. |
| if (Kind.isMergeable2ByteCString() && !GO->hasExternalLinkage() && |
| GO->getParent()->getDataLayout().getPreferredAlignment( |
| cast<GlobalVariable>(GO)) < 32) |
| return UStringSection; |
| |
| // With MachO only variables whose corresponding symbol starts with 'l' or |
| // 'L' can be merged, so we only try merging GVs with private linkage. |
| if (GO->hasPrivateLinkage() && Kind.isMergeableConst()) { |
| if (Kind.isMergeableConst4()) |
| return FourByteConstantSection; |
| if (Kind.isMergeableConst8()) |
| return EightByteConstantSection; |
| if (Kind.isMergeableConst16()) |
| return SixteenByteConstantSection; |
| } |
| |
| // Otherwise, if it is readonly, but not something we can specially optimize, |
| // just drop it in .const. |
| if (Kind.isReadOnly()) |
| return ReadOnlySection; |
| |
| // If this is marked const, put it into a const section. But if the dynamic |
| // linker needs to write to it, put it in the data segment. |
| if (Kind.isReadOnlyWithRel()) |
| return ConstDataSection; |
| |
| // Put zero initialized globals with strong external linkage in the |
| // DATA, __common section with the .zerofill directive. |
| if (Kind.isBSSExtern()) |
| return DataCommonSection; |
| |
| // Put zero initialized globals with local linkage in __DATA,__bss directive |
| // with the .zerofill directive (aka .lcomm). |
| if (Kind.isBSSLocal()) |
| return DataBSSSection; |
| |
| // Otherwise, just drop the variable in the normal data section. |
| return DataSection; |
| } |
| |
| MCSection *TargetLoweringObjectFileMachO::getSectionForConstant( |
| const DataLayout &DL, SectionKind Kind, const Constant *C, |
| unsigned &Align) const { |
| // If this constant requires a relocation, we have to put it in the data |
| // segment, not in the text segment. |
| if (Kind.isData() || Kind.isReadOnlyWithRel()) |
| return ConstDataSection; |
| |
| if (Kind.isMergeableConst4()) |
| return FourByteConstantSection; |
| if (Kind.isMergeableConst8()) |
| return EightByteConstantSection; |
| if (Kind.isMergeableConst16()) |
| return SixteenByteConstantSection; |
| return ReadOnlySection; // .const |
| } |
| |
| const MCExpr *TargetLoweringObjectFileMachO::getTTypeGlobalReference( |
| const GlobalValue *GV, unsigned Encoding, const TargetMachine &TM, |
| MachineModuleInfo *MMI, MCStreamer &Streamer) const { |
| // The mach-o version of this method defaults to returning a stub reference. |
| |
| if (Encoding & DW_EH_PE_indirect) { |
| MachineModuleInfoMachO &MachOMMI = |
| MMI->getObjFileInfo<MachineModuleInfoMachO>(); |
| |
| MCSymbol *SSym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr", TM); |
| |
| // Add information about the stub reference to MachOMMI so that the stub |
| // gets emitted by the asmprinter. |
| MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(SSym); |
| if (!StubSym.getPointer()) { |
| MCSymbol *Sym = TM.getSymbol(GV); |
| StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage()); |
| } |
| |
| return TargetLoweringObjectFile:: |
| getTTypeReference(MCSymbolRefExpr::create(SSym, getContext()), |
| Encoding & ~DW_EH_PE_indirect, Streamer); |
| } |
| |
| return TargetLoweringObjectFile::getTTypeGlobalReference(GV, Encoding, TM, |
| MMI, Streamer); |
| } |
| |
| MCSymbol *TargetLoweringObjectFileMachO::getCFIPersonalitySymbol( |
| const GlobalValue *GV, const TargetMachine &TM, |
| MachineModuleInfo *MMI) const { |
| // The mach-o version of this method defaults to returning a stub reference. |
| MachineModuleInfoMachO &MachOMMI = |
| MMI->getObjFileInfo<MachineModuleInfoMachO>(); |
| |
| MCSymbol *SSym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr", TM); |
| |
| // Add information about the stub reference to MachOMMI so that the stub |
| // gets emitted by the asmprinter. |
| MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(SSym); |
| if (!StubSym.getPointer()) { |
| MCSymbol *Sym = TM.getSymbol(GV); |
| StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage()); |
| } |
| |
| return SSym; |
| } |
| |
| const MCExpr *TargetLoweringObjectFileMachO::getIndirectSymViaGOTPCRel( |
| const MCSymbol *Sym, const MCValue &MV, int64_t Offset, |
| MachineModuleInfo *MMI, MCStreamer &Streamer) const { |
| // Although MachO 32-bit targets do not explicitly have a GOTPCREL relocation |
| // as 64-bit do, we replace the GOT equivalent by accessing the final symbol |
| // through a non_lazy_ptr stub instead. One advantage is that it allows the |
| // computation of deltas to final external symbols. Example: |
| // |
| // _extgotequiv: |
| // .long _extfoo |
| // |
| // _delta: |
| // .long _extgotequiv-_delta |
| // |
| // is transformed to: |
| // |
| // _delta: |
| // .long L_extfoo$non_lazy_ptr-(_delta+0) |
| // |
| // .section __IMPORT,__pointers,non_lazy_symbol_pointers |
| // L_extfoo$non_lazy_ptr: |
| // .indirect_symbol _extfoo |
| // .long 0 |
| // |
| MachineModuleInfoMachO &MachOMMI = |
| MMI->getObjFileInfo<MachineModuleInfoMachO>(); |
| MCContext &Ctx = getContext(); |
| |
| // The offset must consider the original displacement from the base symbol |
| // since 32-bit targets don't have a GOTPCREL to fold the PC displacement. |
| Offset = -MV.getConstant(); |
| const MCSymbol *BaseSym = &MV.getSymB()->getSymbol(); |
| |
| // Access the final symbol via sym$non_lazy_ptr and generate the appropriated |
| // non_lazy_ptr stubs. |
| SmallString<128> Name; |
| StringRef Suffix = "$non_lazy_ptr"; |
| Name += MMI->getModule()->getDataLayout().getPrivateGlobalPrefix(); |
| Name += Sym->getName(); |
| Name += Suffix; |
| MCSymbol *Stub = Ctx.getOrCreateSymbol(Name); |
| |
| MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(Stub); |
| if (!StubSym.getPointer()) |
| StubSym = MachineModuleInfoImpl:: |
| StubValueTy(const_cast<MCSymbol *>(Sym), true /* access indirectly */); |
| |
| const MCExpr *BSymExpr = |
| MCSymbolRefExpr::create(BaseSym, MCSymbolRefExpr::VK_None, Ctx); |
| const MCExpr *LHS = |
| MCSymbolRefExpr::create(Stub, MCSymbolRefExpr::VK_None, Ctx); |
| |
| if (!Offset) |
| return MCBinaryExpr::createSub(LHS, BSymExpr, Ctx); |
| |
| const MCExpr *RHS = |
| MCBinaryExpr::createAdd(BSymExpr, MCConstantExpr::create(Offset, Ctx), Ctx); |
| return MCBinaryExpr::createSub(LHS, RHS, Ctx); |
| } |
| |
| static bool canUsePrivateLabel(const MCAsmInfo &AsmInfo, |
| const MCSection &Section) { |
| if (!AsmInfo.isSectionAtomizableBySymbols(Section)) |
| return true; |
| |
| // If it is not dead stripped, it is safe to use private labels. |
| const MCSectionMachO &SMO = cast<MCSectionMachO>(Section); |
| if (SMO.hasAttribute(MachO::S_ATTR_NO_DEAD_STRIP)) |
| return true; |
| |
| return false; |
| } |
| |
| void TargetLoweringObjectFileMachO::getNameWithPrefix( |
| SmallVectorImpl<char> &OutName, const GlobalValue *GV, |
| const TargetMachine &TM) const { |
| bool CannotUsePrivateLabel = true; |
| if (auto *GO = GV->getBaseObject()) { |
| SectionKind GOKind = TargetLoweringObjectFile::getKindForGlobal(GO, TM); |
| const MCSection *TheSection = SectionForGlobal(GO, GOKind, TM); |
| CannotUsePrivateLabel = |
| !canUsePrivateLabel(*TM.getMCAsmInfo(), *TheSection); |
| } |
| getMangler().getNameWithPrefix(OutName, GV, CannotUsePrivateLabel); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // COFF |
| //===----------------------------------------------------------------------===// |
| |
| static unsigned |
| getCOFFSectionFlags(SectionKind K, const TargetMachine &TM) { |
| unsigned Flags = 0; |
| bool isThumb = TM.getTargetTriple().getArch() == Triple::thumb; |
| |
| if (K.isMetadata()) |
| Flags |= |
| COFF::IMAGE_SCN_MEM_DISCARDABLE; |
| else if (K.isText()) |
| Flags |= |
| COFF::IMAGE_SCN_MEM_EXECUTE | |
| COFF::IMAGE_SCN_MEM_READ | |
| COFF::IMAGE_SCN_CNT_CODE | |
| (isThumb ? COFF::IMAGE_SCN_MEM_16BIT : (COFF::SectionCharacteristics)0); |
| else if (K.isBSS()) |
| Flags |= |
| COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA | |
| COFF::IMAGE_SCN_MEM_READ | |
| COFF::IMAGE_SCN_MEM_WRITE; |
| else if (K.isThreadLocal()) |
| Flags |= |
| COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | |
| COFF::IMAGE_SCN_MEM_READ | |
| COFF::IMAGE_SCN_MEM_WRITE; |
| else if (K.isReadOnly() || K.isReadOnlyWithRel()) |
| Flags |= |
| COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | |
| COFF::IMAGE_SCN_MEM_READ; |
| else if (K.isWriteable()) |
| Flags |= |
| COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | |
| COFF::IMAGE_SCN_MEM_READ | |
| COFF::IMAGE_SCN_MEM_WRITE; |
| |
| return Flags; |
| } |
| |
| static const GlobalValue *getComdatGVForCOFF(const GlobalValue *GV) { |
| const Comdat *C = GV->getComdat(); |
| assert(C && "expected GV to have a Comdat!"); |
| |
| StringRef ComdatGVName = C->getName(); |
| const GlobalValue *ComdatGV = GV->getParent()->getNamedValue(ComdatGVName); |
| if (!ComdatGV) |
| report_fatal_error("Associative COMDAT symbol '" + ComdatGVName + |
| "' does not exist."); |
| |
| if (ComdatGV->getComdat() != C) |
| report_fatal_error("Associative COMDAT symbol '" + ComdatGVName + |
| "' is not a key for its COMDAT."); |
| |
| return ComdatGV; |
| } |
| |
| static int getSelectionForCOFF(const GlobalValue *GV) { |
| if (const Comdat *C = GV->getComdat()) { |
| const GlobalValue *ComdatKey = getComdatGVForCOFF(GV); |
| if (const auto *GA = dyn_cast<GlobalAlias>(ComdatKey)) |
| ComdatKey = GA->getBaseObject(); |
| if (ComdatKey == GV) { |
| switch (C->getSelectionKind()) { |
| case Comdat::Any: |
| return COFF::IMAGE_COMDAT_SELECT_ANY; |
| case Comdat::ExactMatch: |
| return COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH; |
| case Comdat::Largest: |
| return COFF::IMAGE_COMDAT_SELECT_LARGEST; |
| case Comdat::NoDuplicates: |
| return COFF::IMAGE_COMDAT_SELECT_NODUPLICATES; |
| case Comdat::SameSize: |
| return COFF::IMAGE_COMDAT_SELECT_SAME_SIZE; |
| } |
| } else { |
| return COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE; |
| } |
| } |
| return 0; |
| } |
| |
| MCSection *TargetLoweringObjectFileCOFF::getExplicitSectionGlobal( |
| const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const { |
| int Selection = 0; |
| unsigned Characteristics = getCOFFSectionFlags(Kind, TM); |
| StringRef Name = GO->getSection(); |
| StringRef COMDATSymName = ""; |
| if (GO->hasComdat()) { |
| Selection = getSelectionForCOFF(GO); |
| const GlobalValue *ComdatGV; |
| if (Selection == COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE) |
| ComdatGV = getComdatGVForCOFF(GO); |
| else |
| ComdatGV = GO; |
| |
| if (!ComdatGV->hasPrivateLinkage()) { |
| MCSymbol *Sym = TM.getSymbol(ComdatGV); |
| COMDATSymName = Sym->getName(); |
| Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT; |
| } else { |
| Selection = 0; |
| } |
| } |
| |
| return getContext().getCOFFSection(Name, Characteristics, Kind, COMDATSymName, |
| Selection); |
| } |
| |
| static StringRef getCOFFSectionNameForUniqueGlobal(SectionKind Kind) { |
| if (Kind.isText()) |
| return ".text"; |
| if (Kind.isBSS()) |
| return ".bss"; |
| if (Kind.isThreadLocal()) |
| return ".tls$"; |
| if (Kind.isReadOnly() || Kind.isReadOnlyWithRel()) |
| return ".rdata"; |
| return ".data"; |
| } |
| |
| MCSection *TargetLoweringObjectFileCOFF::SelectSectionForGlobal( |
| const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const { |
| // If we have -ffunction-sections then we should emit the global value to a |
| // uniqued section specifically for it. |
| bool EmitUniquedSection; |
| if (Kind.isText()) |
| EmitUniquedSection = TM.getFunctionSections(); |
| else |
| EmitUniquedSection = TM.getDataSections(); |
| |
| if ((EmitUniquedSection && !Kind.isCommon()) || GO->hasComdat()) { |
| SmallString<256> Name = getCOFFSectionNameForUniqueGlobal(Kind); |
| |
| unsigned Characteristics = getCOFFSectionFlags(Kind, TM); |
| |
| Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT; |
| int Selection = getSelectionForCOFF(GO); |
| if (!Selection) |
| Selection = COFF::IMAGE_COMDAT_SELECT_NODUPLICATES; |
| const GlobalValue *ComdatGV; |
| if (GO->hasComdat()) |
| ComdatGV = getComdatGVForCOFF(GO); |
| else |
| ComdatGV = GO; |
| |
| unsigned UniqueID = MCContext::GenericSectionID; |
| if (EmitUniquedSection) |
| UniqueID = NextUniqueID++; |
| |
| if (!ComdatGV->hasPrivateLinkage()) { |
| MCSymbol *Sym = TM.getSymbol(ComdatGV); |
| StringRef COMDATSymName = Sym->getName(); |
| |
| // Append "$symbol" to the section name when targetting mingw. The ld.bfd |
| // COFF linker will not properly handle comdats otherwise. |
| if (getTargetTriple().isWindowsGNUEnvironment()) |
| raw_svector_ostream(Name) << '$' << COMDATSymName; |
| |
| return getContext().getCOFFSection(Name, Characteristics, Kind, |
| COMDATSymName, Selection, UniqueID); |
| } else { |
| SmallString<256> TmpData; |
| getMangler().getNameWithPrefix(TmpData, GO, /*CannotUsePrivateLabel=*/true); |
| return getContext().getCOFFSection(Name, Characteristics, Kind, TmpData, |
| Selection, UniqueID); |
| } |
| } |
| |
| if (Kind.isText()) |
| return TextSection; |
| |
| if (Kind.isThreadLocal()) |
| return TLSDataSection; |
| |
| if (Kind.isReadOnly() || Kind.isReadOnlyWithRel()) |
| return ReadOnlySection; |
| |
| // Note: we claim that common symbols are put in BSSSection, but they are |
| // really emitted with the magic .comm directive, which creates a symbol table |
| // entry but not a section. |
| if (Kind.isBSS() || Kind.isCommon()) |
| return BSSSection; |
| |
| return DataSection; |
| } |
| |
| void TargetLoweringObjectFileCOFF::getNameWithPrefix( |
| SmallVectorImpl<char> &OutName, const GlobalValue *GV, |
| const TargetMachine &TM) const { |
| bool CannotUsePrivateLabel = false; |
| if (GV->hasPrivateLinkage() && |
| ((isa<Function>(GV) && TM.getFunctionSections()) || |
| (isa<GlobalVariable>(GV) && TM.getDataSections()))) |
| CannotUsePrivateLabel = true; |
| |
| getMangler().getNameWithPrefix(OutName, GV, CannotUsePrivateLabel); |
| } |
| |
| MCSection *TargetLoweringObjectFileCOFF::getSectionForJumpTable( |
| const Function &F, const TargetMachine &TM) const { |
| // If the function can be removed, produce a unique section so that |
| // the table doesn't prevent the removal. |
| const Comdat *C = F.getComdat(); |
| bool EmitUniqueSection = TM.getFunctionSections() || C; |
| if (!EmitUniqueSection) |
| return ReadOnlySection; |
| |
| // FIXME: we should produce a symbol for F instead. |
| if (F.hasPrivateLinkage()) |
| return ReadOnlySection; |
| |
| MCSymbol *Sym = TM.getSymbol(&F); |
| StringRef COMDATSymName = Sym->getName(); |
| |
| SectionKind Kind = SectionKind::getReadOnly(); |
| StringRef SecName = getCOFFSectionNameForUniqueGlobal(Kind); |
| unsigned Characteristics = getCOFFSectionFlags(Kind, TM); |
| Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT; |
| unsigned UniqueID = NextUniqueID++; |
| |
| return getContext().getCOFFSection( |
| SecName, Characteristics, Kind, COMDATSymName, |
| COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE, UniqueID); |
| } |
| |
| void TargetLoweringObjectFileCOFF::emitModuleMetadata(MCStreamer &Streamer, |
| Module &M) const { |
| if (NamedMDNode *LinkerOptions = M.getNamedMetadata("llvm.linker.options")) { |
| // Emit the linker options to the linker .drectve section. According to the |
| // spec, this section is a space-separated string containing flags for |
| // linker. |
| MCSection *Sec = getDrectveSection(); |
| Streamer.SwitchSection(Sec); |
| for (const auto &Option : LinkerOptions->operands()) { |
| for (const auto &Piece : cast<MDNode>(Option)->operands()) { |
| // Lead with a space for consistency with our dllexport implementation. |
| std::string Directive(" "); |
| Directive.append(cast<MDString>(Piece)->getString()); |
| Streamer.EmitBytes(Directive); |
| } |
| } |
| } |
| |
| unsigned Version = 0; |
| unsigned Flags = 0; |
| StringRef Section; |
| |
| GetObjCImageInfo(M, Version, Flags, Section); |
| if (Section.empty()) |
| return; |
| |
| auto &C = getContext(); |
| auto *S = C.getCOFFSection( |
| Section, COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ, |
| SectionKind::getReadOnly()); |
| Streamer.SwitchSection(S); |
| Streamer.EmitLabel(C.getOrCreateSymbol(StringRef("OBJC_IMAGE_INFO"))); |
| Streamer.EmitIntValue(Version, 4); |
| Streamer.EmitIntValue(Flags, 4); |
| Streamer.AddBlankLine(); |
| } |
| |
| void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx, |
| const TargetMachine &TM) { |
| TargetLoweringObjectFile::Initialize(Ctx, TM); |
| const Triple &T = TM.getTargetTriple(); |
| if (T.isKnownWindowsMSVCEnvironment() || T.isWindowsItaniumEnvironment()) { |
| StaticCtorSection = |
| Ctx.getCOFFSection(".CRT$XCU", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | |
| COFF::IMAGE_SCN_MEM_READ, |
| SectionKind::getReadOnly()); |
| StaticDtorSection = |
| Ctx.getCOFFSection(".CRT$XTX", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | |
| COFF::IMAGE_SCN_MEM_READ, |
| SectionKind::getReadOnly()); |
| } else { |
| StaticCtorSection = Ctx.getCOFFSection( |
| ".ctors", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | |
| COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE, |
| SectionKind::getData()); |
| StaticDtorSection = Ctx.getCOFFSection( |
| ".dtors", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | |
| COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE, |
| SectionKind::getData()); |
| } |
| } |
| |
| static MCSectionCOFF *getCOFFStaticStructorSection(MCContext &Ctx, |
| const Triple &T, bool IsCtor, |
| unsigned Priority, |
| const MCSymbol *KeySym, |
| MCSectionCOFF *Default) { |
| if (T.isKnownWindowsMSVCEnvironment() || T.isWindowsItaniumEnvironment()) { |
| // If the priority is the default, use .CRT$XCU, possibly associative. |
| if (Priority == 65535) |
| return Ctx.getAssociativeCOFFSection(Default, KeySym, 0); |
| |
| // Otherwise, we need to compute a new section name. Low priorities should |
| // run earlier. The linker will sort sections ASCII-betically, and we need a |
| // string that sorts between .CRT$XCA and .CRT$XCU. In the general case, we |
| // make a name like ".CRT$XCT12345", since that runs before .CRT$XCU. Really |
| // low priorities need to sort before 'L', since the CRT uses that |
| // internally, so we use ".CRT$XCA00001" for them. |
| SmallString<24> Name; |
| raw_svector_ostream OS(Name); |
| OS << ".CRT$XC" << (Priority < 200 ? 'A' : 'T') << format("%05u", Priority); |
| MCSectionCOFF *Sec = Ctx.getCOFFSection( |
| Name, COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ, |
| SectionKind::getReadOnly()); |
| return Ctx.getAssociativeCOFFSection(Sec, KeySym, 0); |
| } |
| |
| std::string Name = IsCtor ? ".ctors" : ".dtors"; |
| if (Priority != 65535) |
| raw_string_ostream(Name) << format(".%05u", 65535 - Priority); |
| |
| return Ctx.getAssociativeCOFFSection( |
| Ctx.getCOFFSection(Name, COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | |
| COFF::IMAGE_SCN_MEM_READ | |
| COFF::IMAGE_SCN_MEM_WRITE, |
| SectionKind::getData()), |
| KeySym, 0); |
| } |
| |
| MCSection *TargetLoweringObjectFileCOFF::getStaticCtorSection( |
| unsigned Priority, const MCSymbol *KeySym) const { |
| return getCOFFStaticStructorSection(getContext(), getTargetTriple(), true, |
| Priority, KeySym, |
| cast<MCSectionCOFF>(StaticCtorSection)); |
| } |
| |
| MCSection *TargetLoweringObjectFileCOFF::getStaticDtorSection( |
| unsigned Priority, const MCSymbol *KeySym) const { |
| return getCOFFStaticStructorSection(getContext(), getTargetTriple(), false, |
| Priority, KeySym, |
| cast<MCSectionCOFF>(StaticDtorSection)); |
| } |
| |
| void TargetLoweringObjectFileCOFF::emitLinkerFlagsForGlobal( |
| raw_ostream &OS, const GlobalValue *GV) const { |
| emitLinkerFlagsForGlobalCOFF(OS, GV, getTargetTriple(), getMangler()); |
| } |
| |
| void TargetLoweringObjectFileCOFF::emitLinkerFlagsForUsed( |
| raw_ostream &OS, const GlobalValue *GV) const { |
| emitLinkerFlagsForUsedCOFF(OS, GV, getTargetTriple(), getMangler()); |
| } |
| |
| const MCExpr *TargetLoweringObjectFileCOFF::lowerRelativeReference( |
| const GlobalValue *LHS, const GlobalValue *RHS, |
| const TargetMachine &TM) const { |
| const Triple &T = TM.getTargetTriple(); |
| if (!T.isKnownWindowsMSVCEnvironment() && |
| !T.isWindowsItaniumEnvironment() && |
| !T.isWindowsCoreCLREnvironment()) |
| return nullptr; |
| |
| // Our symbols should exist in address space zero, cowardly no-op if |
| // otherwise. |
| if (LHS->getType()->getPointerAddressSpace() != 0 || |
| RHS->getType()->getPointerAddressSpace() != 0) |
| return nullptr; |
| |
| // Both ptrtoint instructions must wrap global objects: |
| // - Only global variables are eligible for image relative relocations. |
| // - The subtrahend refers to the special symbol __ImageBase, a GlobalVariable. |
| // We expect __ImageBase to be a global variable without a section, externally |
| // defined. |
| // |
| // It should look something like this: @__ImageBase = external constant i8 |
| if (!isa<GlobalObject>(LHS) || !isa<GlobalVariable>(RHS) || |
| LHS->isThreadLocal() || RHS->isThreadLocal() || |
| RHS->getName() != "__ImageBase" || !RHS->hasExternalLinkage() || |
| cast<GlobalVariable>(RHS)->hasInitializer() || RHS->hasSection()) |
| return nullptr; |
| |
| return MCSymbolRefExpr::create(TM.getSymbol(LHS), |
| MCSymbolRefExpr::VK_COFF_IMGREL32, |
| getContext()); |
| } |
| |
| static std::string APIntToHexString(const APInt &AI) { |
| unsigned Width = (AI.getBitWidth() / 8) * 2; |
| std::string HexString = utohexstr(AI.getLimitedValue(), /*LowerCase=*/true); |
| unsigned Size = HexString.size(); |
| assert(Width >= Size && "hex string is too large!"); |
| HexString.insert(HexString.begin(), Width - Size, '0'); |
| |
| return HexString; |
| } |
| |
| static std::string scalarConstantToHexString(const Constant *C) { |
| Type *Ty = C->getType(); |
| if (isa<UndefValue>(C)) { |
| return APIntToHexString(APInt::getNullValue(Ty->getPrimitiveSizeInBits())); |
| } else if (const auto *CFP = dyn_cast<ConstantFP>(C)) { |
| return APIntToHexString(CFP->getValueAPF().bitcastToAPInt()); |
| } else if (const auto *CI = dyn_cast<ConstantInt>(C)) { |
| return APIntToHexString(CI->getValue()); |
| } else { |
| unsigned NumElements; |
| if (isa<VectorType>(Ty)) |
| NumElements = Ty->getVectorNumElements(); |
| else |
| NumElements = Ty->getArrayNumElements(); |
| std::string HexString; |
| for (int I = NumElements - 1, E = -1; I != E; --I) |
| HexString += scalarConstantToHexString(C->getAggregateElement(I)); |
| return HexString; |
| } |
| } |
| |
| MCSection *TargetLoweringObjectFileCOFF::getSectionForConstant( |
| const DataLayout &DL, SectionKind Kind, const Constant *C, |
| unsigned &Align) const { |
| if (Kind.isMergeableConst() && C && |
| getContext().getAsmInfo()->hasCOFFComdatConstants()) { |
| // This creates comdat sections with the given symbol name, but unless |
| // AsmPrinter::GetCPISymbol actually makes the symbol global, the symbol |
| // will be created with a null storage class, which makes GNU binutils |
| // error out. |
| const unsigned Characteristics = COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | |
| COFF::IMAGE_SCN_MEM_READ | |
| COFF::IMAGE_SCN_LNK_COMDAT; |
| std::string COMDATSymName; |
| if (Kind.isMergeableConst4()) { |
| if (Align <= 4) { |
| COMDATSymName = "__real@" + scalarConstantToHexString(C); |
| Align = 4; |
| } |
| } else if (Kind.isMergeableConst8()) { |
| if (Align <= 8) { |
| COMDATSymName = "__real@" + scalarConstantToHexString(C); |
| Align = 8; |
| } |
| } else if (Kind.isMergeableConst16()) { |
| // FIXME: These may not be appropriate for non-x86 architectures. |
| if (Align <= 16) { |
| COMDATSymName = "__xmm@" + scalarConstantToHexString(C); |
| Align = 16; |
| } |
| } else if (Kind.isMergeableConst32()) { |
| if (Align <= 32) { |
| COMDATSymName = "__ymm@" + scalarConstantToHexString(C); |
| Align = 32; |
| } |
| } |
| |
| if (!COMDATSymName.empty()) |
| return getContext().getCOFFSection(".rdata", Characteristics, Kind, |
| COMDATSymName, |
| COFF::IMAGE_COMDAT_SELECT_ANY); |
| } |
| |
| return TargetLoweringObjectFile::getSectionForConstant(DL, Kind, C, Align); |
| } |
| |
| |
| //===----------------------------------------------------------------------===// |
| // Wasm |
| //===----------------------------------------------------------------------===// |
| |
| static const Comdat *getWasmComdat(const GlobalValue *GV) { |
| const Comdat *C = GV->getComdat(); |
| if (!C) |
| return nullptr; |
| |
| if (C->getSelectionKind() != Comdat::Any) |
| report_fatal_error("WebAssembly COMDATs only support " |
| "SelectionKind::Any, '" + C->getName() + "' cannot be " |
| "lowered."); |
| |
| return C; |
| } |
| |
| static SectionKind getWasmKindForNamedSection(StringRef Name, SectionKind K) { |
| // If we're told we have function data, then use that. |
| if (K.isText()) |
| return SectionKind::getText(); |
| |
| // Otherwise, ignore whatever section type the generic impl detected and use |
| // a plain data section. |
| return SectionKind::getData(); |
| } |
| |
| MCSection *TargetLoweringObjectFileWasm::getExplicitSectionGlobal( |
| const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const { |
| // We don't support explict section names for functions in the wasm object |
| // format. Each function has to be in its own unique section. |
| if (isa<Function>(GO)) { |
| return SelectSectionForGlobal(GO, Kind, TM); |
| } |
| |
| StringRef Name = GO->getSection(); |
| |
| Kind = getWasmKindForNamedSection(Name, Kind); |
| |
| StringRef Group = ""; |
| if (const Comdat *C = getWasmComdat(GO)) { |
| Group = C->getName(); |
| } |
| |
| return getContext().getWasmSection(Name, Kind, Group, |
| MCContext::GenericSectionID); |
| } |
| |
| static MCSectionWasm *selectWasmSectionForGlobal( |
| MCContext &Ctx, const GlobalObject *GO, SectionKind Kind, Mangler &Mang, |
| const TargetMachine &TM, bool EmitUniqueSection, unsigned *NextUniqueID) { |
| StringRef Group = ""; |
| if (const Comdat *C = getWasmComdat(GO)) { |
| Group = C->getName(); |
| } |
| |
| bool UniqueSectionNames = TM.getUniqueSectionNames(); |
| SmallString<128> Name = getSectionPrefixForGlobal(Kind); |
| |
| if (const auto *F = dyn_cast<Function>(GO)) { |
| const auto &OptionalPrefix = F->getSectionPrefix(); |
| if (OptionalPrefix) |
| Name += *OptionalPrefix; |
| } |
| |
| if (EmitUniqueSection && UniqueSectionNames) { |
| Name.push_back('.'); |
| TM.getNameWithPrefix(Name, GO, Mang, true); |
| } |
| unsigned UniqueID = MCContext::GenericSectionID; |
| if (EmitUniqueSection && !UniqueSectionNames) { |
| UniqueID = *NextUniqueID; |
| (*NextUniqueID)++; |
| } |
| return Ctx.getWasmSection(Name, Kind, Group, UniqueID); |
| } |
| |
| MCSection *TargetLoweringObjectFileWasm::SelectSectionForGlobal( |
| const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const { |
| |
| if (Kind.isCommon()) |
| report_fatal_error("mergable sections not supported yet on wasm"); |
| |
| // If we have -ffunction-section or -fdata-section then we should emit the |
| // global value to a uniqued section specifically for it. |
| bool EmitUniqueSection = false; |
| if (Kind.isText()) |
| EmitUniqueSection = TM.getFunctionSections(); |
| else |
| EmitUniqueSection = TM.getDataSections(); |
| EmitUniqueSection |= GO->hasComdat(); |
| |
| return selectWasmSectionForGlobal(getContext(), GO, Kind, getMangler(), TM, |
| EmitUniqueSection, &NextUniqueID); |
| } |
| |
| bool TargetLoweringObjectFileWasm::shouldPutJumpTableInFunctionSection( |
| bool UsesLabelDifference, const Function &F) const { |
| // We can always create relative relocations, so use another section |
| // that can be marked non-executable. |
| return false; |
| } |
| |
| const MCExpr *TargetLoweringObjectFileWasm::lowerRelativeReference( |
| const GlobalValue *LHS, const GlobalValue *RHS, |
| const TargetMachine &TM) const { |
| // We may only use a PLT-relative relocation to refer to unnamed_addr |
| // functions. |
| if (!LHS->hasGlobalUnnamedAddr() || !LHS->getValueType()->isFunctionTy()) |
| return nullptr; |
| |
| // Basic sanity checks. |
| if (LHS->getType()->getPointerAddressSpace() != 0 || |
| RHS->getType()->getPointerAddressSpace() != 0 || LHS->isThreadLocal() || |
| RHS->isThreadLocal()) |
| return nullptr; |
| |
| return MCBinaryExpr::createSub( |
| MCSymbolRefExpr::create(TM.getSymbol(LHS), MCSymbolRefExpr::VK_None, |
| getContext()), |
| MCSymbolRefExpr::create(TM.getSymbol(RHS), getContext()), getContext()); |
| } |
| |
| void TargetLoweringObjectFileWasm::InitializeWasm() { |
| StaticCtorSection = |
| getContext().getWasmSection(".init_array", SectionKind::getData()); |
| |
| // We don't use PersonalityEncoding and LSDAEncoding because we don't emit |
| // .cfi directives. We use TTypeEncoding to encode typeinfo global variables. |
| TTypeEncoding = dwarf::DW_EH_PE_absptr; |
| } |
| |
| MCSection *TargetLoweringObjectFileWasm::getStaticCtorSection( |
| unsigned Priority, const MCSymbol *KeySym) const { |
| return Priority == UINT16_MAX ? |
| StaticCtorSection : |
| getContext().getWasmSection(".init_array." + utostr(Priority), |
| SectionKind::getData()); |
| } |
| |
| MCSection *TargetLoweringObjectFileWasm::getStaticDtorSection( |
| unsigned Priority, const MCSymbol *KeySym) const { |
| llvm_unreachable("@llvm.global_dtors should have been lowered already"); |
| return nullptr; |
| } |
