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Diffstat (limited to 'contrib/llvm-project/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp')
| -rw-r--r-- | contrib/llvm-project/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp | 2680 |
1 files changed, 2680 insertions, 0 deletions
diff --git a/contrib/llvm-project/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/contrib/llvm-project/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp new file mode 100644 index 000000000000..55fb522554fa --- /dev/null +++ b/contrib/llvm-project/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp @@ -0,0 +1,2680 @@ +//===- llvm/CodeGen/TargetLoweringObjectFileImpl.cpp - Object File Info ---===// +// +// 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 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/BinaryFormat/COFF.h" +#include "llvm/BinaryFormat/Dwarf.h" +#include "llvm/BinaryFormat/ELF.h" +#include "llvm/BinaryFormat/MachO.h" +#include "llvm/BinaryFormat/Wasm.h" +#include "llvm/CodeGen/BasicBlockSectionUtils.h" +#include "llvm/CodeGen/MachineBasicBlock.h" +#include "llvm/CodeGen/MachineFunction.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/DiagnosticInfo.h" +#include "llvm/IR/DiagnosticPrinter.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/PseudoProbe.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/MCSectionGOFF.h" +#include "llvm/MC/MCSectionMachO.h" +#include "llvm/MC/MCSectionWasm.h" +#include "llvm/MC/MCSectionXCOFF.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/Base64.h" +#include "llvm/Support/Casting.h" +#include "llvm/Support/CodeGen.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/Format.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/Target/TargetMachine.h" +#include "llvm/TargetParser/Triple.h" +#include <cassert> +#include <string> + +using namespace llvm; +using namespace dwarf; + +static cl::opt<bool> JumpTableInFunctionSection( + "jumptable-in-function-section", cl::Hidden, cl::init(false), + cl::desc("Putting Jump Table in function section")); + +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(); + } + // Backend generates L_OBJC_IMAGE_INFO from Swift ABI version + major + minor + + // "Objective-C Garbage Collection". + else if (Key == "Swift ABI Version") { + Flags |= (mdconst::extract<ConstantInt>(MFE.Val)->getZExtValue()) << 8; + } else if (Key == "Swift Major Version") { + Flags |= (mdconst::extract<ConstantInt>(MFE.Val)->getZExtValue()) << 24; + } else if (Key == "Swift Minor Version") { + Flags |= (mdconst::extract<ConstantInt>(MFE.Val)->getZExtValue()) << 16; + } + } +} + +//===----------------------------------------------------------------------===// +// ELF +//===----------------------------------------------------------------------===// + +TargetLoweringObjectFileELF::TargetLoweringObjectFileELF() { + SupportDSOLocalEquivalentLowering = true; +} + +void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx, + const TargetMachine &TgtM) { + TargetLoweringObjectFile::Initialize(Ctx, TgtM); + + CodeModel::Model CM = TgtM.getCodeModel(); + InitializeELF(TgtM.Options.UseInitArray); + + 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 + [[fallthrough]]; + case Triple::ppc: + case Triple::ppcle: + 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_sdata4 : dwarf::DW_EH_PE_sdata8); + } 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: + case Triple::aarch64_32: + // 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. + // + // Use DW_EH_PE_indirect even for -fno-pic to avoid copy relocations. + LSDAEncoding = dwarf::DW_EH_PE_pcrel | + (TgtM.getTargetTriple().getEnvironment() == Triple::GNUILP32 + ? dwarf::DW_EH_PE_sdata4 + : dwarf::DW_EH_PE_sdata8); + PersonalityEncoding = LSDAEncoding | dwarf::DW_EH_PE_indirect; + TTypeEncoding = LSDAEncoding | dwarf::DW_EH_PE_indirect; + 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; + } + CallSiteEncoding = dwarf::DW_EH_PE_udata4; + break; + case Triple::riscv32: + case Triple::riscv64: + 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; + CallSiteEncoding = dwarf::DW_EH_PE_udata4; + 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; + case Triple::loongarch32: + case Triple::loongarch64: + 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; + break; + default: + break; + } +} + +void TargetLoweringObjectFileELF::getModuleMetadata(Module &M) { + SmallVector<GlobalValue *, 4> Vec; + collectUsedGlobalVariables(M, Vec, false); + for (GlobalValue *GV : Vec) + if (auto *GO = dyn_cast<GlobalObject>(GV)) + Used.insert(GO); +} + +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.emitInt8(0); + } + } + } + + if (NamedMDNode *DependentLibraries = M.getNamedMetadata("llvm.dependent-libraries")) { + auto *S = C.getELFSection(".deplibs", ELF::SHT_LLVM_DEPENDENT_LIBRARIES, + ELF::SHF_MERGE | ELF::SHF_STRINGS, 1); + + Streamer.switchSection(S); + + for (const auto *Operand : DependentLibraries->operands()) { + Streamer.emitBytes( + cast<MDString>(cast<MDNode>(Operand)->getOperand(0))->getString()); + Streamer.emitInt8(0); + } + } + + if (NamedMDNode *FuncInfo = M.getNamedMetadata(PseudoProbeDescMetadataName)) { + // Emit a descriptor for every function including functions that have an + // available external linkage. We may not want this for imported functions + // that has code in another thinLTO module but we don't have a good way to + // tell them apart from inline functions defined in header files. Therefore + // we put each descriptor in a separate comdat section and rely on the + // linker to deduplicate. + for (const auto *Operand : FuncInfo->operands()) { + const auto *MD = cast<MDNode>(Operand); + auto *GUID = mdconst::dyn_extract<ConstantInt>(MD->getOperand(0)); + auto *Hash = mdconst::dyn_extract<ConstantInt>(MD->getOperand(1)); + auto *Name = cast<MDString>(MD->getOperand(2)); + auto *S = C.getObjectFileInfo()->getPseudoProbeDescSection( + TM->getFunctionSections() ? Name->getString() : StringRef()); + + Streamer.switchSection(S); + Streamer.emitInt64(GUID->getZExtValue()); + Streamer.emitInt64(Hash->getZExtValue()); + Streamer.emitULEB128IntValue(Name->getString().size()); + Streamer.emitBytes(Name->getString()); + } + } + + if (NamedMDNode *LLVMStats = M.getNamedMetadata("llvm.stats")) { + // Emit the metadata for llvm statistics into .llvm_stats section, which is + // formatted as a list of key/value pair, the value is base64 encoded. + auto *S = C.getObjectFileInfo()->getLLVMStatsSection(); + Streamer.switchSection(S); + for (const auto *Operand : LLVMStats->operands()) { + const auto *MD = cast<MDNode>(Operand); + assert(MD->getNumOperands() % 2 == 0 && + ("Operand num should be even for a list of key/value pair")); + for (size_t I = 0; I < MD->getNumOperands(); I += 2) { + // Encode the key string size. + auto *Key = cast<MDString>(MD->getOperand(I)); + Streamer.emitULEB128IntValue(Key->getString().size()); + Streamer.emitBytes(Key->getString()); + // Encode the value into a Base64 string. + std::string Value = encodeBase64( + Twine(mdconst::dyn_extract<ConstantInt>(MD->getOperand(I + 1)) + ->getZExtValue()) + .str()); + Streamer.emitULEB128IntValue(Value.size()); + Streamer.emitBytes(Value); + } + } + } + + 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.emitInt32(Version); + Streamer.emitInt32(Flags); + Streamer.addBlankLine(); + } + + emitCGProfileMetadata(Streamer, M); +} + +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) || + Name == getInstrProfSectionName(IPSK_covfun, Triple::ELF, + /*AddSegmentInfo=*/false) || + Name == ".llvmbc" || Name == ".llvmcmd") + 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 bool hasPrefix(StringRef SectionName, StringRef Prefix) { + return SectionName.consume_front(Prefix) && + (SectionName.empty() || SectionName[0] == '.'); +} + +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 (hasPrefix(Name, ".init_array")) + return ELF::SHT_INIT_ARRAY; + + if (hasPrefix(Name, ".fini_array")) + return ELF::SHT_FINI_ARRAY; + + if (hasPrefix(Name, ".preinit_array")) + return ELF::SHT_PREINIT_ARRAY; + + if (hasPrefix(Name, ".llvm.offloading")) + return ELF::SHT_LLVM_OFFLOADING; + + if (K.isBSS() || K.isThreadBSS()) + return ELF::SHT_NOBITS; + + return ELF::SHT_PROGBITS; +} + +static unsigned getELFSectionFlags(SectionKind K) { + unsigned Flags = 0; + + if (!K.isMetadata() && !K.isExclude()) + Flags |= ELF::SHF_ALLOC; + + if (K.isExclude()) + Flags |= ELF::SHF_EXCLUDE; + + 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 && + C->getSelectionKind() != Comdat::NoDeduplicate) + report_fatal_error("ELF COMDATs only support SelectionKind::Any and " + "SelectionKind::NoDeduplicate, '" + + C->getName() + "' cannot be lowered."); + + return C; +} + +static const MCSymbolELF *getLinkedToSymbol(const GlobalObject *GO, + const TargetMachine &TM) { + MDNode *MD = GO->getMetadata(LLVMContext::MD_associated); + if (!MD) + return nullptr; + + auto *VM = cast<ValueAsMetadata>(MD->getOperand(0).get()); + auto *OtherGV = dyn_cast<GlobalValue>(VM->getValue()); + return OtherGV ? dyn_cast<MCSymbolELF>(TM.getSymbol(OtherGV)) : 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; + } +} + +/// Return the section prefix name used by options FunctionsSections and +/// DataSections. +static StringRef getSectionPrefixForGlobal(SectionKind Kind, bool IsLarge) { + if (Kind.isText()) + return ".text"; + if (Kind.isReadOnly()) + return IsLarge ? ".lrodata" : ".rodata"; + if (Kind.isBSS()) + return IsLarge ? ".lbss" : ".bss"; + if (Kind.isThreadData()) + return ".tdata"; + if (Kind.isThreadBSS()) + return ".tbss"; + if (Kind.isData()) + return IsLarge ? ".ldata" : ".data"; + if (Kind.isReadOnlyWithRel()) + return IsLarge ? ".ldata.rel.ro" : ".data.rel.ro"; + llvm_unreachable("Unknown section kind"); +} + +static SmallString<128> +getELFSectionNameForGlobal(const GlobalObject *GO, SectionKind Kind, + Mangler &Mang, const TargetMachine &TM, + unsigned EntrySize, bool UniqueSectionName) { + 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! + Align Alignment = GO->getParent()->getDataLayout().getPreferredAlign( + cast<GlobalVariable>(GO)); + + std::string SizeSpec = ".rodata.str" + utostr(EntrySize) + "."; + Name = SizeSpec + utostr(Alignment.value()); + } else if (Kind.isMergeableConst()) { + Name = ".rodata.cst"; + Name += utostr(EntrySize); + } else { + bool IsLarge = false; + if (isa<GlobalVariable>(GO)) + IsLarge = TM.isLargeData(); + Name = getSectionPrefixForGlobal(Kind, IsLarge); + } + + bool HasPrefix = false; + if (const auto *F = dyn_cast<Function>(GO)) { + if (std::optional<StringRef> Prefix = F->getSectionPrefix()) { + raw_svector_ostream(Name) << '.' << *Prefix; + HasPrefix = true; + } + } + + if (UniqueSectionName) { + Name.push_back('.'); + TM.getNameWithPrefix(Name, GO, Mang, /*MayAlwaysUsePrivate*/true); + } else if (HasPrefix) + // For distinguishing between .text.${text-section-prefix}. (with trailing + // dot) and .text.${function-name} + Name.push_back('.'); + return Name; +} + +namespace { +class LoweringDiagnosticInfo : public DiagnosticInfo { + const Twine &Msg; + +public: + LoweringDiagnosticInfo(const Twine &DiagMsg, + DiagnosticSeverity Severity = DS_Error) + : DiagnosticInfo(DK_Lowering, Severity), Msg(DiagMsg) {} + void print(DiagnosticPrinter &DP) const override { DP << Msg; } +}; +} + +/// Calculate an appropriate unique ID for a section, and update Flags, +/// EntrySize and NextUniqueID where appropriate. +static unsigned +calcUniqueIDUpdateFlagsAndSize(const GlobalObject *GO, StringRef SectionName, + SectionKind Kind, const TargetMachine &TM, + MCContext &Ctx, Mangler &Mang, unsigned &Flags, + unsigned &EntrySize, unsigned &NextUniqueID, + const bool Retain, const bool ForceUnique) { + // Increment uniqueID if we are forced to emit a unique section. + // This works perfectly fine with section attribute or pragma section as the + // sections with the same name are grouped together by the assembler. + if (ForceUnique) + return NextUniqueID++; + + // A section can have at most one associated section. Put each global with + // MD_associated in a unique section. + const bool Associated = GO->getMetadata(LLVMContext::MD_associated); + if (Associated) { + Flags |= ELF::SHF_LINK_ORDER; + return NextUniqueID++; + } + + if (Retain) { + if (TM.getTargetTriple().isOSSolaris()) + Flags |= ELF::SHF_SUNW_NODISCARD; + else if (Ctx.getAsmInfo()->useIntegratedAssembler() || + Ctx.getAsmInfo()->binutilsIsAtLeast(2, 36)) + Flags |= ELF::SHF_GNU_RETAIN; + return NextUniqueID++; + } + + // If two symbols with differing sizes end up in the same mergeable section + // that section can be assigned an incorrect entry size. To avoid this we + // usually put symbols of the same size into distinct mergeable sections with + // the same name. Doing so relies on the ",unique ," assembly feature. This + // feature is not avalible until bintuils version 2.35 + // (https://sourceware.org/bugzilla/show_bug.cgi?id=25380). + const bool SupportsUnique = Ctx.getAsmInfo()->useIntegratedAssembler() || + Ctx.getAsmInfo()->binutilsIsAtLeast(2, 35); + if (!SupportsUnique) { + Flags &= ~ELF::SHF_MERGE; + EntrySize = 0; + return MCContext::GenericSectionID; + } + + const bool SymbolMergeable = Flags & ELF::SHF_MERGE; + const bool SeenSectionNameBefore = + Ctx.isELFGenericMergeableSection(SectionName); + // If this is the first ocurrence of this section name, treat it as the + // generic section + if (!SymbolMergeable && !SeenSectionNameBefore) + return MCContext::GenericSectionID; + + // Symbols must be placed into sections with compatible entry sizes. Generate + // unique sections for symbols that have not been assigned to compatible + // sections. + const auto PreviousID = + Ctx.getELFUniqueIDForEntsize(SectionName, Flags, EntrySize); + if (PreviousID) + return *PreviousID; + + // If the user has specified the same section name as would be created + // implicitly for this symbol e.g. .rodata.str1.1, then we don't need + // to unique the section as the entry size for this symbol will be + // compatible with implicitly created sections. + SmallString<128> ImplicitSectionNameStem = + getELFSectionNameForGlobal(GO, Kind, Mang, TM, EntrySize, false); + if (SymbolMergeable && + Ctx.isELFImplicitMergeableSectionNamePrefix(SectionName) && + SectionName.startswith(ImplicitSectionNameStem)) + return MCContext::GenericSectionID; + + // We have seen this section name before, but with different flags or entity + // size. Create a new unique ID. + return NextUniqueID++; +} + +static MCSection *selectExplicitSectionGlobal( + const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM, + MCContext &Ctx, Mangler &Mang, unsigned &NextUniqueID, + bool Retain, bool ForceUnique) { + 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("relro-section") && Kind.isReadOnlyWithRel()) { + SectionName = Attrs.getAttribute("relro-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 = ""; + bool IsComdat = false; + unsigned Flags = getELFSectionFlags(Kind); + if (const Comdat *C = getELFComdat(GO)) { + Group = C->getName(); + IsComdat = C->getSelectionKind() == Comdat::Any; + Flags |= ELF::SHF_GROUP; + } + + unsigned EntrySize = getEntrySizeForKind(Kind); + const unsigned UniqueID = calcUniqueIDUpdateFlagsAndSize( + GO, SectionName, Kind, TM, Ctx, Mang, Flags, EntrySize, NextUniqueID, + Retain, ForceUnique); + + const MCSymbolELF *LinkedToSym = getLinkedToSymbol(GO, TM); + MCSectionELF *Section = Ctx.getELFSection( + SectionName, getELFSectionType(SectionName, Kind), Flags, EntrySize, + Group, IsComdat, UniqueID, LinkedToSym); + // 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->getLinkedToSymbol() == LinkedToSym && + "Associated symbol mismatch between sections"); + + if (!(Ctx.getAsmInfo()->useIntegratedAssembler() || + Ctx.getAsmInfo()->binutilsIsAtLeast(2, 35))) { + // If we are using GNU as before 2.35, then this symbol might have + // been placed in an incompatible mergeable section. Emit an error if this + // is the case to avoid creating broken output. + if ((Section->getFlags() & ELF::SHF_MERGE) && + (Section->getEntrySize() != getEntrySizeForKind(Kind))) + GO->getContext().diagnose(LoweringDiagnosticInfo( + "Symbol '" + GO->getName() + "' from module '" + + (GO->getParent() ? GO->getParent()->getSourceFileName() : "unknown") + + "' required a section with entry-size=" + + Twine(getEntrySizeForKind(Kind)) + " but was placed in section '" + + SectionName + "' with entry-size=" + Twine(Section->getEntrySize()) + + ": Explicit assignment by pragma or attribute of an incompatible " + "symbol to this section?")); + } + + return Section; +} + +MCSection *TargetLoweringObjectFileELF::getExplicitSectionGlobal( + const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const { + return selectExplicitSectionGlobal(GO, Kind, TM, getContext(), getMangler(), + NextUniqueID, Used.count(GO), + /* ForceUnique = */false); +} + +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 = ""; + bool IsComdat = false; + if (const Comdat *C = getELFComdat(GO)) { + Flags |= ELF::SHF_GROUP; + Group = C->getName(); + IsComdat = C->getSelectionKind() == Comdat::Any; + } + if (isa<GlobalVariable>(GO)) { + if (TM.isLargeData()) { + assert(TM.getTargetTriple().getArch() == Triple::x86_64); + Flags |= ELF::SHF_X86_64_LARGE; + } + } + + // Get the section entry size based on the kind. + unsigned EntrySize = getEntrySizeForKind(Kind); + + bool UniqueSectionName = false; + unsigned UniqueID = MCContext::GenericSectionID; + if (EmitUniqueSection) { + if (TM.getUniqueSectionNames()) { + UniqueSectionName = true; + } else { + UniqueID = *NextUniqueID; + (*NextUniqueID)++; + } + } + SmallString<128> Name = getELFSectionNameForGlobal( + GO, Kind, Mang, TM, EntrySize, UniqueSectionName); + + // 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, IsComdat, UniqueID, + AssociatedSymbol); +} + +static MCSection *selectELFSectionForGlobal( + MCContext &Ctx, const GlobalObject *GO, SectionKind Kind, Mangler &Mang, + const TargetMachine &TM, bool Retain, bool EmitUniqueSection, + unsigned Flags, unsigned *NextUniqueID) { + const MCSymbolELF *LinkedToSym = getLinkedToSymbol(GO, TM); + if (LinkedToSym) { + EmitUniqueSection = true; + Flags |= ELF::SHF_LINK_ORDER; + } + if (Retain) { + if (TM.getTargetTriple().isOSSolaris()) { + EmitUniqueSection = true; + Flags |= ELF::SHF_SUNW_NODISCARD; + } else if (Ctx.getAsmInfo()->useIntegratedAssembler() || + Ctx.getAsmInfo()->binutilsIsAtLeast(2, 36)) { + EmitUniqueSection = true; + Flags |= ELF::SHF_GNU_RETAIN; + } + } + + MCSectionELF *Section = selectELFSectionForGlobal( + Ctx, GO, Kind, Mang, TM, EmitUniqueSection, Flags, + NextUniqueID, LinkedToSym); + assert(Section->getLinkedToSymbol() == LinkedToSym); + return Section; +} + +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(); + return selectELFSectionForGlobal(getContext(), GO, Kind, getMangler(), TM, + Used.count(GO), EmitUniqueSection, Flags, + &NextUniqueID); +} + +MCSection *TargetLoweringObjectFileELF::getUniqueSectionForFunction( + const Function &F, const TargetMachine &TM) const { + SectionKind Kind = SectionKind::getText(); + unsigned Flags = getELFSectionFlags(Kind); + // If the function's section names is pre-determined via pragma or a + // section attribute, call selectExplicitSectionGlobal. + if (F.hasSection() || F.hasFnAttribute("implicit-section-name")) + return selectExplicitSectionGlobal( + &F, Kind, TM, getContext(), getMangler(), NextUniqueID, + Used.count(&F), /* ForceUnique = */true); + else + return selectELFSectionForGlobal( + getContext(), &F, Kind, getMangler(), TM, Used.count(&F), + /*EmitUniqueSection=*/true, Flags, &NextUniqueID); +} + +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); +} + +MCSection *TargetLoweringObjectFileELF::getSectionForLSDA( + const Function &F, const MCSymbol &FnSym, const TargetMachine &TM) const { + // If neither COMDAT nor function sections, use the monolithic LSDA section. + // Re-use this path if LSDASection is null as in the Arm EHABI. + if (!LSDASection || (!F.hasComdat() && !TM.getFunctionSections())) + return LSDASection; + + const auto *LSDA = cast<MCSectionELF>(LSDASection); + unsigned Flags = LSDA->getFlags(); + const MCSymbolELF *LinkedToSym = nullptr; + StringRef Group; + bool IsComdat = false; + if (const Comdat *C = getELFComdat(&F)) { + Flags |= ELF::SHF_GROUP; + Group = C->getName(); + IsComdat = C->getSelectionKind() == Comdat::Any; + } + // Use SHF_LINK_ORDER to facilitate --gc-sections if we can use GNU ld>=2.36 + // or LLD, which support mixed SHF_LINK_ORDER & non-SHF_LINK_ORDER. + if (TM.getFunctionSections() && + (getContext().getAsmInfo()->useIntegratedAssembler() && + getContext().getAsmInfo()->binutilsIsAtLeast(2, 36))) { + Flags |= ELF::SHF_LINK_ORDER; + LinkedToSym = cast<MCSymbolELF>(&FnSym); + } + + // Append the function name as the suffix like GCC, assuming + // -funique-section-names applies to .gcc_except_table sections. + return getContext().getELFSection( + (TM.getUniqueSectionNames() ? LSDA->getName() + "." + F.getName() + : LSDA->getName()), + LSDA->getType(), Flags, 0, Group, IsComdat, MCSection::NonUniqueID, + LinkedToSym); +} + +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, + Align &Alignment) 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; +} + +/// Returns a unique section for the given machine basic block. +MCSection *TargetLoweringObjectFileELF::getSectionForMachineBasicBlock( + const Function &F, const MachineBasicBlock &MBB, + const TargetMachine &TM) const { + assert(MBB.isBeginSection() && "Basic block does not start a section!"); + unsigned UniqueID = MCContext::GenericSectionID; + + // For cold sections use the .text.split. prefix along with the parent + // function name. All cold blocks for the same function go to the same + // section. Similarly all exception blocks are grouped by symbol name + // under the .text.eh prefix. For regular sections, we either use a unique + // name, or a unique ID for the section. + SmallString<128> Name; + if (MBB.getSectionID() == MBBSectionID::ColdSectionID) { + Name += BBSectionsColdTextPrefix; + Name += MBB.getParent()->getName(); + } else if (MBB.getSectionID() == MBBSectionID::ExceptionSectionID) { + Name += ".text.eh."; + Name += MBB.getParent()->getName(); + } else { + Name += MBB.getParent()->getSection()->getName(); + if (TM.getUniqueBasicBlockSectionNames()) { + if (!Name.endswith(".")) + Name += "."; + Name += MBB.getSymbol()->getName(); + } else { + UniqueID = NextUniqueID++; + } + } + + unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_EXECINSTR; + std::string GroupName; + if (F.hasComdat()) { + Flags |= ELF::SHF_GROUP; + GroupName = F.getComdat()->getName().str(); + } + return getContext().getELFSection(Name, ELF::SHT_PROGBITS, Flags, + 0 /* Entry Size */, GroupName, + F.hasComdat(), UniqueID, nullptr); +} + +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, /*IsComdat=*/true); +} + +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 correctness 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()); +} + +const MCExpr *TargetLoweringObjectFileELF::lowerDSOLocalEquivalent( + const DSOLocalEquivalent *Equiv, const TargetMachine &TM) const { + assert(supportDSOLocalEquivalentLowering()); + + const auto *GV = Equiv->getGlobalValue(); + + // A PLT entry is not needed for dso_local globals. + if (GV->isDSOLocal() || GV->isImplicitDSOLocal()) + return MCSymbolRefExpr::create(TM.getSymbol(GV), getContext()); + + return MCSymbolRefExpr::create(TM.getSymbol(GV), PLTRelativeVariantKind, + getContext()); +} + +MCSection *TargetLoweringObjectFileELF::getSectionForCommandLines() const { + // Use ".GCC.command.line" since this feature is to support clang's + // -frecord-gcc-switches which in turn attempts to mimic GCC's switch of the + // same name. + return getContext().getELFSection(".GCC.command.line", ELF::SHT_PROGBITS, + ELF::SHF_MERGE | ELF::SHF_STRINGS, 1); +} + +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() { + 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; +} + +MCSection *TargetLoweringObjectFileMachO::getStaticDtorSection( + unsigned Priority, const MCSymbol *KeySym) const { + return StaticDtorSection; + // In userspace, we lower global destructors via atexit(), but kernel/kext + // environments do not provide this function so we still need to support the + // legacy way here. + // See the -disable-atexit-based-global-dtor-lowering CodeGen flag for more + // context. +} + +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(std::string(cast<MDString>(Piece)->getString())); + Streamer.emitLinkerOptions(StrOptions); + } + } + + unsigned VersionVal = 0; + unsigned ImageInfoFlags = 0; + StringRef SectionVal; + + GetObjCImageInfo(M, VersionVal, ImageInfoFlags, SectionVal); + emitCGProfileMetadata(Streamer, M); + + // 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; + if (Error E = MCSectionMachO::ParseSectionSpecifier( + SectionVal, Segment, Section, TAA, TAAParsed, StubSize)) { + // If invalid, report the error with report_fatal_error. + report_fatal_error("Invalid section specifier '" + Section + + "': " + toString(std::move(E)) + "."); + } + + // 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.emitInt32(VersionVal); + Streamer.emitInt32(ImageInfoFlags); + 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 { + + StringRef SectionName = GO->getSection(); + + 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("relro-section") && Kind.isReadOnlyWithRel()) { + SectionName = Attrs.getAttribute("relro-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(); + } + + // Parse the section specifier and create it if valid. + StringRef Segment, Section; + unsigned TAA = 0, StubSize = 0; + bool TAAParsed; + + checkMachOComdat(GO); + + if (Error E = MCSectionMachO::ParseSectionSpecifier( + SectionName, Segment, Section, TAA, TAAParsed, StubSize)) { + // If invalid, report the error with report_fatal_error. + report_fatal_error("Global variable '" + GO->getName() + + "' has an invalid section specifier '" + + GO->getSection() + "': " + toString(std::move(E)) + "."); + } + + // 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().getPreferredAlign( + cast<GlobalVariable>(GO)) < Align(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().getPreferredAlign( + cast<GlobalVariable>(GO)) < Align(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, + Align &Alignment) 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 +} + +MCSection *TargetLoweringObjectFileMachO::getSectionForCommandLines() const { + return getContext().getMachOSection("__TEXT", "__command_line", 0, + SectionKind::getReadOnly()); +} + +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 GlobalValue *GV, 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 + // + // The indirect symbol table (and sections of non_lazy_symbol_pointers type) + // may point to both local (same translation unit) and global (other + // translation units) symbols. Example: + // + // .section __DATA,__pointers,non_lazy_symbol_pointers + // L1: + // .indirect_symbol _myGlobal + // .long 0 + // L2: + // .indirect_symbol _myLocal + // .long _myLocal + // + // If the symbol is local, instead of the symbol's index, the assembler + // places the constant INDIRECT_SYMBOL_LOCAL into the indirect symbol table. + // Then the linker will notice the constant in the table and will look at the + // content of the symbol. + 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), + !GV->hasLocalLinkage()); + + 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; + + // FIXME: we should be able to use private labels for sections that can't be + // dead-stripped (there's no issue with blocking atomization there), but `ld + // -r` sometimes drops the no_dead_strip attribute from sections so for safety + // we don't allow it. + return false; +} + +void TargetLoweringObjectFileMachO::getNameWithPrefix( + SmallVectorImpl<char> &OutName, const GlobalValue *GV, + const TargetMachine &TM) const { + bool CannotUsePrivateLabel = true; + if (auto *GO = GV->getAliaseeObject()) { + 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.isExclude()) + Flags |= + COFF::IMAGE_SCN_LNK_REMOVE | 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->getAliaseeObject(); + 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::NoDeduplicate: + 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$"; + if (Kind.isReadOnly() || Kind.isReadOnlyWithRel()) + return ".rdata"; + return ".data"; +} + +MCSection *TargetLoweringObjectFileCOFF::SelectSectionForGlobal( + const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const { + // If we have -ffunction-sections then we should emit the global value to a + // uniqued section specifically for it. + bool EmitUniquedSection; + if (Kind.isText()) + EmitUniquedSection = TM.getFunctionSections(); + else + EmitUniquedSection = TM.getDataSections(); + + if ((EmitUniquedSection && !Kind.isCommon()) || GO->hasComdat()) { + SmallString<256> Name = getCOFFSectionNameForUniqueGlobal(Kind); + + unsigned Characteristics = getCOFFSectionFlags(Kind, TM); + + Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT; + int Selection = getSelectionForCOFF(GO); + if (!Selection) + Selection = COFF::IMAGE_COMDAT_SELECT_NODUPLICATES; + const GlobalValue *ComdatGV; + if (GO->hasComdat()) + ComdatGV = getComdatGVForCOFF(GO); + else + ComdatGV = GO; + + unsigned UniqueID = MCContext::GenericSectionID; + if (EmitUniquedSection) + UniqueID = NextUniqueID++; + + if (!ComdatGV->hasPrivateLinkage()) { + MCSymbol *Sym = TM.getSymbol(ComdatGV); + StringRef COMDATSymName = Sym->getName(); + + if (const auto *F = dyn_cast<Function>(GO)) + if (std::optional<StringRef> Prefix = F->getSectionPrefix()) + raw_svector_ostream(Name) << '$' << *Prefix; + + // Append "$symbol" to the section name *before* IR-level mangling is + // applied when targetting mingw. This is what GCC does, and the ld.bfd + // COFF linker will not properly handle comdats otherwise. + if (getContext().getTargetTriple().isWindowsGNUEnvironment()) + raw_svector_ostream(Name) << '$' << ComdatGV->getName(); + + 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); +} + +bool TargetLoweringObjectFileCOFF::shouldPutJumpTableInFunctionSection( + bool UsesLabelDifference, const Function &F) const { + if (TM->getTargetTriple().getArch() == Triple::x86_64) { + if (!JumpTableInFunctionSection) { + // We can always create relative relocations, so use another section + // that can be marked non-executable. + return false; + } + } + return TargetLoweringObjectFile::shouldPutJumpTableInFunctionSection( + UsesLabelDifference, F); +} + +void TargetLoweringObjectFileCOFF::emitModuleMetadata(MCStreamer &Streamer, + Module &M) const { + emitLinkerDirectives(Streamer, M); + + unsigned Version = 0; + unsigned Flags = 0; + StringRef Section; + + GetObjCImageInfo(M, Version, Flags, Section); + if (!Section.empty()) { + 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.emitInt32(Version); + Streamer.emitInt32(Flags); + Streamer.addBlankLine(); + } + + emitCGProfileMetadata(Streamer, M); +} + +void TargetLoweringObjectFileCOFF::emitLinkerDirectives( + 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(std::string(cast<MDString>(Piece)->getString())); + Streamer.emitBytes(Directive); + } + } + } + + // Emit /EXPORT: flags for each exported global as necessary. + std::string Flags; + for (const GlobalValue &GV : M.global_values()) { + raw_string_ostream OS(Flags); + emitLinkerFlagsForGlobalCOFF(OS, &GV, getContext().getTargetTriple(), + getMangler()); + OS.flush(); + if (!Flags.empty()) { + Streamer.switchSection(getDrectveSection()); + Streamer.emitBytes(Flags); + } + Flags.clear(); + } + + // Emit /INCLUDE: flags for each used global as necessary. + if (const auto *LU = M.getNamedGlobal("llvm.used")) { + assert(LU->hasInitializer() && "expected llvm.used to have an initializer"); + assert(isa<ArrayType>(LU->getValueType()) && + "expected llvm.used to be an array type"); + if (const auto *A = cast<ConstantArray>(LU->getInitializer())) { + for (const Value *Op : A->operands()) { + const auto *GV = cast<GlobalValue>(Op->stripPointerCasts()); + // Global symbols with internal or private linkage are not visible to + // the linker, and thus would cause an error when the linker tried to + // preserve the symbol due to the `/include:` directive. + if (GV->hasLocalLinkage()) + continue; + + raw_string_ostream OS(Flags); + emitLinkerFlagsForUsedCOFF(OS, GV, getContext().getTargetTriple(), + getMangler()); + OS.flush(); + + if (!Flags.empty()) { + Streamer.switchSection(getDrectveSection()); + Streamer.emitBytes(Flags); + } + Flags.clear(); + } + } + } +} + +void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx, + const TargetMachine &TM) { + TargetLoweringObjectFile::Initialize(Ctx, TM); + this->TM = &TM; + const Triple &T = TM.getTargetTriple(); + if (T.isWindowsMSVCEnvironment() || 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.isWindowsMSVCEnvironment() || 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. We have a contract with + // the frontend that "init_seg(compiler)" corresponds to priority 200 and + // "init_seg(lib)" corresponds to priority 400, and those respectively use + // 'C' and 'L' without the priority suffix. Priorities between 200 and 400 + // use 'C' with the priority as a suffix. + SmallString<24> Name; + char LastLetter = 'T'; + bool AddPrioritySuffix = Priority != 200 && Priority != 400; + if (Priority < 200) + LastLetter = 'A'; + else if (Priority < 400) + LastLetter = 'C'; + else if (Priority == 400) + LastLetter = 'L'; + raw_svector_ostream OS(Name); + OS << ".CRT$X" << (IsCtor ? "C" : "T") << LastLetter; + if (AddPrioritySuffix) + OS << 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(), getContext().getTargetTriple(), true, Priority, KeySym, + cast<MCSectionCOFF>(StaticCtorSection)); +} + +MCSection *TargetLoweringObjectFileCOFF::getStaticDtorSection( + unsigned Priority, const MCSymbol *KeySym) const { + return getCOFFStaticStructorSection( + getContext(), getContext().getTargetTriple(), false, Priority, KeySym, + cast<MCSectionCOFF>(StaticDtorSection)); +} + +const MCExpr *TargetLoweringObjectFileCOFF::lowerRelativeReference( + const GlobalValue *LHS, const GlobalValue *RHS, + const TargetMachine &TM) const { + const Triple &T = TM.getTargetTriple(); + if (T.isOSCygMing()) + 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 = toString(AI, 16, /*Signed=*/false); + llvm::transform(HexString, HexString.begin(), tolower); + 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::getZero(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 (auto *VTy = dyn_cast<VectorType>(Ty)) + NumElements = cast<FixedVectorType>(VTy)->getNumElements(); + 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, + Align &Alignment) 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 (Alignment <= 4) { + COMDATSymName = "__real@" + scalarConstantToHexString(C); + Alignment = Align(4); + } + } else if (Kind.isMergeableConst8()) { + if (Alignment <= 8) { + COMDATSymName = "__real@" + scalarConstantToHexString(C); + Alignment = Align(8); + } + } else if (Kind.isMergeableConst16()) { + // FIXME: These may not be appropriate for non-x86 architectures. + if (Alignment <= 16) { + COMDATSymName = "__xmm@" + scalarConstantToHexString(C); + Alignment = Align(16); + } + } else if (Kind.isMergeableConst32()) { + if (Alignment <= 32) { + COMDATSymName = "__ymm@" + scalarConstantToHexString(C); + Alignment = Align(32); + } + } + + if (!COMDATSymName.empty()) + return getContext().getCOFFSection(".rdata", Characteristics, Kind, + COMDATSymName, + COFF::IMAGE_COMDAT_SELECT_ANY); + } + + return TargetLoweringObjectFile::getSectionForConstant(DL, Kind, C, + Alignment); +} + +//===----------------------------------------------------------------------===// +// 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 unsigned getWasmSectionFlags(SectionKind K) { + unsigned Flags = 0; + + if (K.isThreadLocal()) + Flags |= wasm::WASM_SEG_FLAG_TLS; + + if (K.isMergeableCString()) + Flags |= wasm::WASM_SEG_FLAG_STRINGS; + + // TODO(sbc): Add suport for K.isMergeableConst() + + return Flags; +} + +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(); + + // Certain data sections we treat as named custom sections rather than + // segments within the data section. + // This could be avoided if all data segements (the wasm sense) were + // represented as their own sections (in the llvm sense). + // TODO(sbc): https://github.com/WebAssembly/tool-conventions/issues/138 + if (Name == ".llvmcmd" || Name == ".llvmbc") + Kind = SectionKind::getMetadata(); + + StringRef Group = ""; + if (const Comdat *C = getWasmComdat(GO)) { + Group = C->getName(); + } + + unsigned Flags = getWasmSectionFlags(Kind); + MCSectionWasm *Section = getContext().getWasmSection( + Name, Kind, Flags, Group, MCContext::GenericSectionID); + + return Section; +} + +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, /*IsLarge=*/false); + + if (const auto *F = dyn_cast<Function>(GO)) { + const auto &OptionalPrefix = F->getSectionPrefix(); + if (OptionalPrefix) + raw_svector_ostream(Name) << '.' << *OptionalPrefix; + } + + if (EmitUniqueSection && UniqueSectionNames) { + Name.push_back('.'); + TM.getNameWithPrefix(Name, GO, Mang, true); + } + unsigned UniqueID = MCContext::GenericSectionID; + if (EmitUniqueSection && !UniqueSectionNames) { + UniqueID = *NextUniqueID; + (*NextUniqueID)++; + } + + unsigned Flags = getWasmSectionFlags(Kind); + return Ctx.getWasmSection(Name, Kind, Flags, 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 correctness 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 { + report_fatal_error("@llvm.global_dtors should have been lowered already"); +} + +//===----------------------------------------------------------------------===// +// XCOFF +//===----------------------------------------------------------------------===// +bool TargetLoweringObjectFileXCOFF::ShouldEmitEHBlock( + const MachineFunction *MF) { + if (!MF->getLandingPads().empty()) + return true; + + const Function &F = MF->getFunction(); + if (!F.hasPersonalityFn() || !F.needsUnwindTableEntry()) + return false; + + const GlobalValue *Per = + dyn_cast<GlobalValue>(F.getPersonalityFn()->stripPointerCasts()); + assert(Per && "Personality routine is not a GlobalValue type."); + if (isNoOpWithoutInvoke(classifyEHPersonality(Per))) + return false; + + return true; +} + +bool TargetLoweringObjectFileXCOFF::ShouldSetSSPCanaryBitInTB( + const MachineFunction *MF) { + const Function &F = MF->getFunction(); + if (!F.hasStackProtectorFnAttr()) + return false; + // FIXME: check presence of canary word + // There are cases that the stack protectors are not really inserted even if + // the attributes are on. + return true; +} + +MCSymbol * +TargetLoweringObjectFileXCOFF::getEHInfoTableSymbol(const MachineFunction *MF) { + return MF->getMMI().getContext().getOrCreateSymbol( + "__ehinfo." + Twine(MF->getFunctionNumber())); +} + +MCSymbol * +TargetLoweringObjectFileXCOFF::getTargetSymbol(const GlobalValue *GV, + const TargetMachine &TM) const { + // We always use a qualname symbol for a GV that represents + // a declaration, a function descriptor, or a common symbol. + // If a GV represents a GlobalVariable and -fdata-sections is enabled, we + // also return a qualname so that a label symbol could be avoided. + // It is inherently ambiguous when the GO represents the address of a + // function, as the GO could either represent a function descriptor or a + // function entry point. We choose to always return a function descriptor + // here. + if (const GlobalObject *GO = dyn_cast<GlobalObject>(GV)) { + if (GO->isDeclarationForLinker()) + return cast<MCSectionXCOFF>(getSectionForExternalReference(GO, TM)) + ->getQualNameSymbol(); + + if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) + if (GVar->hasAttribute("toc-data")) + return cast<MCSectionXCOFF>( + SectionForGlobal(GVar, SectionKind::getData(), TM)) + ->getQualNameSymbol(); + + SectionKind GOKind = getKindForGlobal(GO, TM); + if (GOKind.isText()) + return cast<MCSectionXCOFF>( + getSectionForFunctionDescriptor(cast<Function>(GO), TM)) + ->getQualNameSymbol(); + if ((TM.getDataSections() && !GO->hasSection()) || GO->hasCommonLinkage() || + GOKind.isBSSLocal() || GOKind.isThreadBSSLocal()) + return cast<MCSectionXCOFF>(SectionForGlobal(GO, GOKind, TM)) + ->getQualNameSymbol(); + } + + // For all other cases, fall back to getSymbol to return the unqualified name. + return nullptr; +} + +MCSection *TargetLoweringObjectFileXCOFF::getExplicitSectionGlobal( + const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const { + if (!GO->hasSection()) + report_fatal_error("#pragma clang section is not yet supported"); + + StringRef SectionName = GO->getSection(); + + // Handle the XCOFF::TD case first, then deal with the rest. + if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GO)) + if (GVar->hasAttribute("toc-data")) + return getContext().getXCOFFSection( + SectionName, Kind, + XCOFF::CsectProperties(/*MappingClass*/ XCOFF::XMC_TD, XCOFF::XTY_SD), + /* MultiSymbolsAllowed*/ true); + + XCOFF::StorageMappingClass MappingClass; + if (Kind.isText()) + MappingClass = XCOFF::XMC_PR; + else if (Kind.isData() || Kind.isBSS()) + MappingClass = XCOFF::XMC_RW; + else if (Kind.isReadOnlyWithRel()) + MappingClass = + TM.Options.XCOFFReadOnlyPointers ? XCOFF::XMC_RO : XCOFF::XMC_RW; + else if (Kind.isReadOnly()) + MappingClass = XCOFF::XMC_RO; + else + report_fatal_error("XCOFF other section types not yet implemented."); + + return getContext().getXCOFFSection( + SectionName, Kind, XCOFF::CsectProperties(MappingClass, XCOFF::XTY_SD), + /* MultiSymbolsAllowed*/ true); +} + +MCSection *TargetLoweringObjectFileXCOFF::getSectionForExternalReference( + const GlobalObject *GO, const TargetMachine &TM) const { + assert(GO->isDeclarationForLinker() && + "Tried to get ER section for a defined global."); + + SmallString<128> Name; + getNameWithPrefix(Name, GO, TM); + + XCOFF::StorageMappingClass SMC = + isa<Function>(GO) ? XCOFF::XMC_DS : XCOFF::XMC_UA; + if (GO->isThreadLocal()) + SMC = XCOFF::XMC_UL; + + if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GO)) + if (GVar->hasAttribute("toc-data")) + SMC = XCOFF::XMC_TD; + + // Externals go into a csect of type ER. + return getContext().getXCOFFSection( + Name, SectionKind::getMetadata(), + XCOFF::CsectProperties(SMC, XCOFF::XTY_ER)); +} + +MCSection *TargetLoweringObjectFileXCOFF::SelectSectionForGlobal( + const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const { + // Handle the XCOFF::TD case first, then deal with the rest. + if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GO)) + if (GVar->hasAttribute("toc-data")) { + SmallString<128> Name; + getNameWithPrefix(Name, GO, TM); + return getContext().getXCOFFSection( + Name, Kind, XCOFF::CsectProperties(XCOFF::XMC_TD, XCOFF::XTY_SD), + /* MultiSymbolsAllowed*/ true); + } + + // Common symbols go into a csect with matching name which will get mapped + // into the .bss section. + // Zero-initialized local TLS symbols go into a csect with matching name which + // will get mapped into the .tbss section. + if (Kind.isBSSLocal() || GO->hasCommonLinkage() || Kind.isThreadBSSLocal()) { + SmallString<128> Name; + getNameWithPrefix(Name, GO, TM); + XCOFF::StorageMappingClass SMC = Kind.isBSSLocal() ? XCOFF::XMC_BS + : Kind.isCommon() ? XCOFF::XMC_RW + : XCOFF::XMC_UL; + return getContext().getXCOFFSection( + Name, Kind, XCOFF::CsectProperties(SMC, XCOFF::XTY_CM)); + } + + if (Kind.isText()) { + if (TM.getFunctionSections()) { + return cast<MCSymbolXCOFF>(getFunctionEntryPointSymbol(GO, TM)) + ->getRepresentedCsect(); + } + return TextSection; + } + + if (TM.Options.XCOFFReadOnlyPointers && Kind.isReadOnlyWithRel()) { + if (!TM.getDataSections()) + report_fatal_error( + "ReadOnlyPointers is supported only if data sections is turned on"); + + SmallString<128> Name; + getNameWithPrefix(Name, GO, TM); + return getContext().getXCOFFSection( + Name, SectionKind::getReadOnly(), + XCOFF::CsectProperties(XCOFF::XMC_RO, XCOFF::XTY_SD)); + } + + // For BSS kind, zero initialized data must be emitted to the .data section + // because external linkage control sections that get mapped to the .bss + // section will be linked as tentative defintions, which is only appropriate + // for SectionKind::Common. + if (Kind.isData() || Kind.isReadOnlyWithRel() || Kind.isBSS()) { + if (TM.getDataSections()) { + SmallString<128> Name; + getNameWithPrefix(Name, GO, TM); + return getContext().getXCOFFSection( + Name, SectionKind::getData(), + XCOFF::CsectProperties(XCOFF::XMC_RW, XCOFF::XTY_SD)); + } + return DataSection; + } + + if (Kind.isReadOnly()) { + if (TM.getDataSections()) { + SmallString<128> Name; + getNameWithPrefix(Name, GO, TM); + return getContext().getXCOFFSection( + Name, SectionKind::getReadOnly(), + XCOFF::CsectProperties(XCOFF::XMC_RO, XCOFF::XTY_SD)); + } + return ReadOnlySection; + } + + // External/weak TLS data and initialized local TLS data are not eligible + // to be put into common csect. If data sections are enabled, thread + // data are emitted into separate sections. Otherwise, thread data + // are emitted into the .tdata section. + if (Kind.isThreadLocal()) { + if (TM.getDataSections()) { + SmallString<128> Name; + getNameWithPrefix(Name, GO, TM); + return getContext().getXCOFFSection( + Name, Kind, XCOFF::CsectProperties(XCOFF::XMC_TL, XCOFF::XTY_SD)); + } + return TLSDataSection; + } + + report_fatal_error("XCOFF other section types not yet implemented."); +} + +MCSection *TargetLoweringObjectFileXCOFF::getSectionForJumpTable( + const Function &F, const TargetMachine &TM) const { + assert (!F.getComdat() && "Comdat not supported on XCOFF."); + + if (!TM.getFunctionSections()) + return ReadOnlySection; + + // If the function can be removed, produce a unique section so that + // the table doesn't prevent the removal. + SmallString<128> NameStr(".rodata.jmp.."); + getNameWithPrefix(NameStr, &F, TM); + return getContext().getXCOFFSection( + NameStr, SectionKind::getReadOnly(), + XCOFF::CsectProperties(XCOFF::XMC_RO, XCOFF::XTY_SD)); +} + +bool TargetLoweringObjectFileXCOFF::shouldPutJumpTableInFunctionSection( + bool UsesLabelDifference, const Function &F) const { + return false; +} + +/// Given a mergeable constant with the specified size and relocation +/// information, return a section that it should be placed in. +MCSection *TargetLoweringObjectFileXCOFF::getSectionForConstant( + const DataLayout &DL, SectionKind Kind, const Constant *C, + Align &Alignment) const { + // TODO: Enable emiting constant pool to unique sections when we support it. + if (Alignment > Align(16)) + report_fatal_error("Alignments greater than 16 not yet supported."); + + if (Alignment == Align(8)) { + assert(ReadOnly8Section && "Section should always be initialized."); + return ReadOnly8Section; + } + + if (Alignment == Align(16)) { + assert(ReadOnly16Section && "Section should always be initialized."); + return ReadOnly16Section; + } + + return ReadOnlySection; +} + +void TargetLoweringObjectFileXCOFF::Initialize(MCContext &Ctx, + const TargetMachine &TgtM) { + TargetLoweringObjectFile::Initialize(Ctx, TgtM); + TTypeEncoding = + dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_datarel | + (TgtM.getTargetTriple().isArch32Bit() ? dwarf::DW_EH_PE_sdata4 + : dwarf::DW_EH_PE_sdata8); + PersonalityEncoding = 0; + LSDAEncoding = 0; + CallSiteEncoding = dwarf::DW_EH_PE_udata4; + + // AIX debug for thread local location is not ready. And for integrated as + // mode, the relocatable address for the thread local variable will cause + // linker error. So disable the location attribute generation for thread local + // variables for now. + // FIXME: when TLS debug on AIX is ready, remove this setting. + SupportDebugThreadLocalLocation = false; +} + +MCSection *TargetLoweringObjectFileXCOFF::getStaticCtorSection( + unsigned Priority, const MCSymbol *KeySym) const { + report_fatal_error("no static constructor section on AIX"); +} + +MCSection *TargetLoweringObjectFileXCOFF::getStaticDtorSection( + unsigned Priority, const MCSymbol *KeySym) const { + report_fatal_error("no static destructor section on AIX"); +} + +const MCExpr *TargetLoweringObjectFileXCOFF::lowerRelativeReference( + const GlobalValue *LHS, const GlobalValue *RHS, + const TargetMachine &TM) const { + /* Not implemented yet, but don't crash, return nullptr. */ + return nullptr; +} + +XCOFF::StorageClass +TargetLoweringObjectFileXCOFF::getStorageClassForGlobal(const GlobalValue *GV) { + assert(!isa<GlobalIFunc>(GV) && "GlobalIFunc is not supported on AIX."); + + switch (GV->getLinkage()) { + case GlobalValue::InternalLinkage: + case GlobalValue::PrivateLinkage: + return XCOFF::C_HIDEXT; + case GlobalValue::ExternalLinkage: + case GlobalValue::CommonLinkage: + case GlobalValue::AvailableExternallyLinkage: + return XCOFF::C_EXT; + case GlobalValue::ExternalWeakLinkage: + case GlobalValue::LinkOnceAnyLinkage: + case GlobalValue::LinkOnceODRLinkage: + case GlobalValue::WeakAnyLinkage: + case GlobalValue::WeakODRLinkage: + return XCOFF::C_WEAKEXT; + case GlobalValue::AppendingLinkage: + report_fatal_error( + "There is no mapping that implements AppendingLinkage for XCOFF."); + } + llvm_unreachable("Unknown linkage type!"); +} + +MCSymbol *TargetLoweringObjectFileXCOFF::getFunctionEntryPointSymbol( + const GlobalValue *Func, const TargetMachine &TM) const { + assert((isa<Function>(Func) || + (isa<GlobalAlias>(Func) && + isa_and_nonnull<Function>( + cast<GlobalAlias>(Func)->getAliaseeObject()))) && + "Func must be a function or an alias which has a function as base " + "object."); + + SmallString<128> NameStr; + NameStr.push_back('.'); + getNameWithPrefix(NameStr, Func, TM); + + // When -function-sections is enabled and explicit section is not specified, + // it's not necessary to emit function entry point label any more. We will use + // function entry point csect instead. And for function delcarations, the + // undefined symbols gets treated as csect with XTY_ER property. + if (((TM.getFunctionSections() && !Func->hasSection()) || + Func->isDeclarationForLinker()) && + isa<Function>(Func)) { + return getContext() + .getXCOFFSection( + NameStr, SectionKind::getText(), + XCOFF::CsectProperties(XCOFF::XMC_PR, Func->isDeclarationForLinker() + ? XCOFF::XTY_ER + : XCOFF::XTY_SD)) + ->getQualNameSymbol(); + } + + return getContext().getOrCreateSymbol(NameStr); +} + +MCSection *TargetLoweringObjectFileXCOFF::getSectionForFunctionDescriptor( + const Function *F, const TargetMachine &TM) const { + SmallString<128> NameStr; + getNameWithPrefix(NameStr, F, TM); + return getContext().getXCOFFSection( + NameStr, SectionKind::getData(), + XCOFF::CsectProperties(XCOFF::XMC_DS, XCOFF::XTY_SD)); +} + +MCSection *TargetLoweringObjectFileXCOFF::getSectionForTOCEntry( + const MCSymbol *Sym, const TargetMachine &TM) const { + // Use TE storage-mapping class when large code model is enabled so that + // the chance of needing -bbigtoc is decreased. + return getContext().getXCOFFSection( + cast<MCSymbolXCOFF>(Sym)->getSymbolTableName(), SectionKind::getData(), + XCOFF::CsectProperties( + TM.getCodeModel() == CodeModel::Large ? XCOFF::XMC_TE : XCOFF::XMC_TC, + XCOFF::XTY_SD)); +} + +MCSection *TargetLoweringObjectFileXCOFF::getSectionForLSDA( + const Function &F, const MCSymbol &FnSym, const TargetMachine &TM) const { + auto *LSDA = cast<MCSectionXCOFF>(LSDASection); + if (TM.getFunctionSections()) { + // If option -ffunction-sections is on, append the function name to the + // name of the LSDA csect so that each function has its own LSDA csect. + // This helps the linker to garbage-collect EH info of unused functions. + SmallString<128> NameStr = LSDA->getName(); + raw_svector_ostream(NameStr) << '.' << F.getName(); + LSDA = getContext().getXCOFFSection(NameStr, LSDA->getKind(), + LSDA->getCsectProp()); + } + return LSDA; +} +//===----------------------------------------------------------------------===// +// GOFF +//===----------------------------------------------------------------------===// +TargetLoweringObjectFileGOFF::TargetLoweringObjectFileGOFF() = default; + +MCSection *TargetLoweringObjectFileGOFF::getExplicitSectionGlobal( + const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const { + return SelectSectionForGlobal(GO, Kind, TM); +} + +MCSection *TargetLoweringObjectFileGOFF::SelectSectionForGlobal( + const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const { + auto *Symbol = TM.getSymbol(GO); + if (Kind.isBSS()) + return getContext().getGOFFSection(Symbol->getName(), SectionKind::getBSS(), + nullptr, nullptr); + + return getContext().getObjectFileInfo()->getTextSection(); +} |