| //===-- llvm/CodeGen/TargetLoweringObjectFileImpl.cpp - Object File Info --===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements classes used to handle lowerings specific to common |
| // object file formats. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h" |
| #include "llvm/ADT/SmallString.h" |
| #include "llvm/ADT/StringExtras.h" |
| #include "llvm/ADT/Triple.h" |
| #include "llvm/CodeGen/MachineModuleInfoImpls.h" |
| #include "llvm/IR/Constants.h" |
| #include "llvm/IR/DataLayout.h" |
| #include "llvm/IR/DerivedTypes.h" |
| #include "llvm/IR/Function.h" |
| #include "llvm/IR/GlobalVariable.h" |
| #include "llvm/IR/Mangler.h" |
| #include "llvm/IR/Module.h" |
| #include "llvm/MC/MCAsmInfo.h" |
| #include "llvm/MC/MCContext.h" |
| #include "llvm/MC/MCExpr.h" |
| #include "llvm/MC/MCSectionCOFF.h" |
| #include "llvm/MC/MCSectionELF.h" |
| #include "llvm/MC/MCSectionMachO.h" |
| #include "llvm/MC/MCStreamer.h" |
| #include "llvm/MC/MCSymbolELF.h" |
| #include "llvm/MC/MCValue.h" |
| #include "llvm/Support/COFF.h" |
| #include "llvm/Support/Dwarf.h" |
| #include "llvm/Support/ELF.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include "llvm/Target/TargetLowering.h" |
| #include "llvm/Target/TargetMachine.h" |
| #include "llvm/Target/TargetSubtargetInfo.h" |
| using namespace llvm; |
| using namespace dwarf; |
| |
| //===----------------------------------------------------------------------===// |
| // ELF |
| //===----------------------------------------------------------------------===// |
| |
| MCSymbol *TargetLoweringObjectFileELF::getCFIPersonalitySymbol( |
| const GlobalValue *GV, Mangler &Mang, const TargetMachine &TM, |
| MachineModuleInfo *MMI) const { |
| unsigned Encoding = getPersonalityEncoding(); |
| if ((Encoding & 0x80) == dwarf::DW_EH_PE_indirect) |
| return getContext().getOrCreateSymbol(StringRef("DW.ref.") + |
| TM.getSymbol(GV, Mang)->getName()); |
| if ((Encoding & 0x70) == dwarf::DW_EH_PE_absptr) |
| return TM.getSymbol(GV, Mang); |
| 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); |
| StringRef Prefix = ".data."; |
| NameData.insert(NameData.begin(), Prefix.begin(), Prefix.end()); |
| unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_GROUP; |
| MCSection *Sec = getContext().getELFSection(NameData, ELF::SHT_PROGBITS, |
| Flags, 0, Label->getName()); |
| unsigned Size = DL.getPointerSize(); |
| Streamer.SwitchSection(Sec); |
| Streamer.EmitValueToAlignment(DL.getPointerABIAlignment()); |
| 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, Mangler &Mang, |
| const TargetMachine &TM, MachineModuleInfo *MMI, |
| MCStreamer &Streamer) const { |
| |
| if (Encoding & dwarf::DW_EH_PE_indirect) { |
| MachineModuleInfoELF &ELFMMI = MMI->getObjFileInfo<MachineModuleInfoELF>(); |
| |
| MCSymbol *SSym = getSymbolWithGlobalValueBase(GV, ".DW.stub", Mang, 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, Mang); |
| StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage()); |
| } |
| |
| return TargetLoweringObjectFile:: |
| getTTypeReference(MCSymbolRefExpr::create(SSym, getContext()), |
| Encoding & ~dwarf::DW_EH_PE_indirect, Streamer); |
| } |
| |
| return TargetLoweringObjectFile:: |
| getTTypeGlobalReference(GV, Encoding, Mang, TM, MMI, Streamer); |
| } |
| |
| static SectionKind |
| getELFKindForNamedSection(StringRef Name, SectionKind K) { |
| // N.B.: The defaults used in here are no 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.empty() || Name[0] != '.') return K; |
| |
| // Some lame default implementation based on some magic section names. |
| if (Name == ".bss" || |
| Name.startswith(".bss.") || |
| Name.startswith(".gnu.linkonce.b.") || |
| Name.startswith(".llvm.linkonce.b.") || |
| Name == ".sbss" || |
| Name.startswith(".sbss.") || |
| Name.startswith(".gnu.linkonce.sb.") || |
| Name.startswith(".llvm.linkonce.sb.")) |
| return SectionKind::getBSS(); |
| |
| if (Name == ".tdata" || |
| Name.startswith(".tdata.") || |
| Name.startswith(".gnu.linkonce.td.") || |
| Name.startswith(".llvm.linkonce.td.")) |
| return SectionKind::getThreadData(); |
| |
| if (Name == ".tbss" || |
| Name.startswith(".tbss.") || |
| Name.startswith(".gnu.linkonce.tb.") || |
| Name.startswith(".llvm.linkonce.tb.")) |
| return SectionKind::getThreadBSS(); |
| |
| return K; |
| } |
| |
| |
| static unsigned getELFSectionType(StringRef Name, SectionKind K) { |
| |
| if (Name == ".init_array") |
| return ELF::SHT_INIT_ARRAY; |
| |
| if (Name == ".fini_array") |
| return ELF::SHT_FINI_ARRAY; |
| |
| if (Name == ".preinit_array") |
| return ELF::SHT_PREINIT_ARRAY; |
| |
| if (K.isBSS() || K.isThreadBSS()) |
| return ELF::SHT_NOBITS; |
| |
| return ELF::SHT_PROGBITS; |
| } |
| |
| static unsigned getELFSectionFlags(SectionKind K) { |
| unsigned Flags = 0; |
| |
| if (!K.isMetadata()) |
| Flags |= ELF::SHF_ALLOC; |
| |
| if (K.isText()) |
| Flags |= ELF::SHF_EXECINSTR; |
| |
| if (K.isWriteable()) |
| Flags |= ELF::SHF_WRITE; |
| |
| if (K.isThreadLocal()) |
| Flags |= ELF::SHF_TLS; |
| |
| if (K.isMergeableCString() || K.isMergeableConst()) |
| Flags |= ELF::SHF_MERGE; |
| |
| if (K.isMergeableCString()) |
| Flags |= ELF::SHF_STRINGS; |
| |
| return Flags; |
| } |
| |
| static const Comdat *getELFComdat(const GlobalValue *GV) { |
| const Comdat *C = GV->getComdat(); |
| if (!C) |
| return nullptr; |
| |
| if (C->getSelectionKind() != Comdat::Any) |
| report_fatal_error("ELF COMDATs only support SelectionKind::Any, '" + |
| C->getName() + "' cannot be lowered."); |
| |
| return C; |
| } |
| |
| MCSection *TargetLoweringObjectFileELF::getExplicitSectionGlobal( |
| const GlobalValue *GV, SectionKind Kind, Mangler &Mang, |
| const TargetMachine &TM) const { |
| StringRef SectionName = GV->getSection(); |
| |
| // Infer section flags from the section name if we can. |
| Kind = getELFKindForNamedSection(SectionName, Kind); |
| |
| StringRef Group = ""; |
| unsigned Flags = getELFSectionFlags(Kind); |
| if (const Comdat *C = getELFComdat(GV)) { |
| Group = C->getName(); |
| Flags |= ELF::SHF_GROUP; |
| } |
| return getContext().getELFSection(SectionName, |
| getELFSectionType(SectionName, Kind), Flags, |
| /*EntrySize=*/0, Group); |
| } |
| |
| /// Return the section prefix name used by options FunctionsSections and |
| /// DataSections. |
| static StringRef getSectionPrefixForGlobal(SectionKind Kind) { |
| if (Kind.isText()) |
| return ".text"; |
| if (Kind.isReadOnly()) |
| return ".rodata"; |
| if (Kind.isBSS()) |
| return ".bss"; |
| if (Kind.isThreadData()) |
| return ".tdata"; |
| if (Kind.isThreadBSS()) |
| return ".tbss"; |
| if (Kind.isData()) |
| return ".data"; |
| assert(Kind.isReadOnlyWithRel() && "Unknown section kind"); |
| return ".data.rel.ro"; |
| } |
| |
| static MCSectionELF * |
| selectELFSectionForGlobal(MCContext &Ctx, const GlobalValue *GV, |
| SectionKind Kind, Mangler &Mang, |
| const TargetMachine &TM, bool EmitUniqueSection, |
| unsigned Flags, unsigned *NextUniqueID) { |
| unsigned EntrySize = 0; |
| if (Kind.isMergeableCString()) { |
| if (Kind.isMergeable2ByteCString()) { |
| EntrySize = 2; |
| } else if (Kind.isMergeable4ByteCString()) { |
| EntrySize = 4; |
| } else { |
| EntrySize = 1; |
| assert(Kind.isMergeable1ByteCString() && "unknown string width"); |
| } |
| } else if (Kind.isMergeableConst()) { |
| if (Kind.isMergeableConst4()) { |
| EntrySize = 4; |
| } else if (Kind.isMergeableConst8()) { |
| EntrySize = 8; |
| } else { |
| assert(Kind.isMergeableConst16() && "unknown data width"); |
| EntrySize = 16; |
| } |
| } |
| |
| StringRef Group = ""; |
| if (const Comdat *C = getELFComdat(GV)) { |
| Flags |= ELF::SHF_GROUP; |
| Group = C->getName(); |
| } |
| |
| bool UniqueSectionNames = TM.getUniqueSectionNames(); |
| SmallString<128> Name; |
| if (Kind.isMergeableCString()) { |
| // We also need alignment here. |
| // FIXME: this is getting the alignment of the character, not the |
| // alignment of the global! |
| unsigned Align = GV->getParent()->getDataLayout().getPreferredAlignment( |
| cast<GlobalVariable>(GV)); |
| |
| std::string SizeSpec = ".rodata.str" + utostr(EntrySize) + "."; |
| Name = SizeSpec + utostr(Align); |
| } else if (Kind.isMergeableConst()) { |
| Name = ".rodata.cst"; |
| Name += utostr(EntrySize); |
| } else { |
| Name = getSectionPrefixForGlobal(Kind); |
| } |
| |
| if (EmitUniqueSection && UniqueSectionNames) { |
| Name.push_back('.'); |
| TM.getNameWithPrefix(Name, GV, Mang, true); |
| } |
| unsigned UniqueID = ~0; |
| if (EmitUniqueSection && !UniqueSectionNames) { |
| UniqueID = *NextUniqueID; |
| (*NextUniqueID)++; |
| } |
| return Ctx.getELFSection(Name, getELFSectionType(Name, Kind), Flags, |
| EntrySize, Group, UniqueID); |
| } |
| |
| MCSection *TargetLoweringObjectFileELF::SelectSectionForGlobal( |
| const GlobalValue *GV, SectionKind Kind, Mangler &Mang, |
| 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 |= GV->hasComdat(); |
| |
| return selectELFSectionForGlobal(getContext(), GV, Kind, Mang, TM, |
| EmitUniqueSection, Flags, &NextUniqueID); |
| } |
| |
| MCSection *TargetLoweringObjectFileELF::getSectionForJumpTable( |
| const Function &F, Mangler &Mang, 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(), |
| Mang, TM, EmitUniqueSection, ELF::SHF_ALLOC, |
| &NextUniqueID); |
| } |
| |
| 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) const { |
| if (Kind.isMergeableConst4() && MergeableConst4Section) |
| return MergeableConst4Section; |
| if (Kind.isMergeableConst8() && MergeableConst8Section) |
| return MergeableConst8Section; |
| if (Kind.isMergeableConst16() && MergeableConst16Section) |
| return MergeableConst16Section; |
| if (Kind.isReadOnly()) |
| return ReadOnlySection; |
| |
| assert(Kind.isReadOnlyWithRel() && "Unknown section kind"); |
| return DataRelROSection; |
| } |
| |
| static MCSectionELF *getStaticStructorSection(MCContext &Ctx, bool UseInitArray, |
| bool IsCtor, unsigned Priority, |
| const MCSymbol *KeySym) { |
| std::string Name; |
| unsigned Type; |
| unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE; |
| StringRef COMDAT = KeySym ? KeySym->getName() : ""; |
| |
| if (KeySym) |
| Flags |= ELF::SHF_GROUP; |
| |
| if (UseInitArray) { |
| if (IsCtor) { |
| Type = ELF::SHT_INIT_ARRAY; |
| Name = ".init_array"; |
| } else { |
| Type = ELF::SHT_FINI_ARRAY; |
| Name = ".fini_array"; |
| } |
| if (Priority != 65535) { |
| Name += '.'; |
| Name += utostr(Priority); |
| } |
| } else { |
| // The default scheme is .ctor / .dtor, so we have to invert the priority |
| // numbering. |
| if (IsCtor) |
| Name = ".ctors"; |
| else |
| Name = ".dtors"; |
| if (Priority != 65535) { |
| Name += '.'; |
| Name += utostr(65535 - Priority); |
| } |
| Type = ELF::SHT_PROGBITS; |
| } |
| |
| return Ctx.getELFSection(Name, Type, Flags, 0, COMDAT); |
| } |
| |
| MCSection *TargetLoweringObjectFileELF::getStaticCtorSection( |
| unsigned Priority, const MCSymbol *KeySym) const { |
| return getStaticStructorSection(getContext(), UseInitArray, true, Priority, |
| KeySym); |
| } |
| |
| MCSection *TargetLoweringObjectFileELF::getStaticDtorSection( |
| unsigned Priority, const MCSymbol *KeySym) const { |
| return getStaticStructorSection(getContext(), UseInitArray, false, Priority, |
| KeySym); |
| } |
| |
| void |
| TargetLoweringObjectFileELF::InitializeELF(bool UseInitArray_) { |
| UseInitArray = UseInitArray_; |
| if (!UseInitArray) |
| return; |
| |
| StaticCtorSection = getContext().getELFSection( |
| ".init_array", ELF::SHT_INIT_ARRAY, ELF::SHF_WRITE | ELF::SHF_ALLOC); |
| StaticDtorSection = getContext().getELFSection( |
| ".fini_array", ELF::SHT_FINI_ARRAY, ELF::SHF_WRITE | ELF::SHF_ALLOC); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // MachO |
| //===----------------------------------------------------------------------===// |
| |
| TargetLoweringObjectFileMachO::TargetLoweringObjectFileMachO() |
| : TargetLoweringObjectFile() { |
| SupportIndirectSymViaGOTPCRel = true; |
| } |
| |
| /// emitModuleFlags - Perform code emission for module flags. |
| void TargetLoweringObjectFileMachO:: |
| emitModuleFlags(MCStreamer &Streamer, |
| ArrayRef<Module::ModuleFlagEntry> ModuleFlags, |
| Mangler &Mang, const TargetMachine &TM) const { |
| unsigned VersionVal = 0; |
| unsigned ImageInfoFlags = 0; |
| MDNode *LinkerOptions = nullptr; |
| StringRef SectionVal; |
| |
| for (ArrayRef<Module::ModuleFlagEntry>::iterator |
| i = ModuleFlags.begin(), e = ModuleFlags.end(); i != e; ++i) { |
| const Module::ModuleFlagEntry &MFE = *i; |
| |
| // Ignore flags with 'Require' behavior. |
| if (MFE.Behavior == Module::Require) |
| continue; |
| |
| StringRef Key = MFE.Key->getString(); |
| Metadata *Val = MFE.Val; |
| |
| if (Key == "Objective-C Image Info Version") { |
| VersionVal = mdconst::extract<ConstantInt>(Val)->getZExtValue(); |
| } else if (Key == "Objective-C Garbage Collection" || |
| Key == "Objective-C GC Only" || |
| Key == "Objective-C Is Simulated" || |
| Key == "Objective-C Image Swift Version") { |
| ImageInfoFlags |= mdconst::extract<ConstantInt>(Val)->getZExtValue(); |
| } else if (Key == "Objective-C Image Info Section") { |
| SectionVal = cast<MDString>(Val)->getString(); |
| } else if (Key == "Linker Options") { |
| LinkerOptions = cast<MDNode>(Val); |
| } |
| } |
| |
| // Emit the linker options if present. |
| if (LinkerOptions) { |
| for (unsigned i = 0, e = LinkerOptions->getNumOperands(); i != e; ++i) { |
| MDNode *MDOptions = cast<MDNode>(LinkerOptions->getOperand(i)); |
| SmallVector<std::string, 4> StrOptions; |
| |
| // Convert to strings. |
| for (unsigned ii = 0, ie = MDOptions->getNumOperands(); ii != ie; ++ii) { |
| MDString *MDOption = cast<MDString>(MDOptions->getOperand(ii)); |
| StrOptions.push_back(MDOption->getString()); |
| } |
| |
| Streamer.EmitLinkerOptions(StrOptions); |
| } |
| } |
| |
| // The section is mandatory. If we don't have it, then we don't have GC info. |
| if (SectionVal.empty()) return; |
| |
| StringRef Segment, Section; |
| unsigned TAA = 0, StubSize = 0; |
| bool TAAParsed; |
| std::string ErrorCode = |
| MCSectionMachO::ParseSectionSpecifier(SectionVal, Segment, Section, |
| TAA, TAAParsed, StubSize); |
| if (!ErrorCode.empty()) |
| // If invalid, report the error with report_fatal_error. |
| report_fatal_error("Invalid section specifier '" + Section + "': " + |
| ErrorCode + "."); |
| |
| // Get the section. |
| MCSectionMachO *S = getContext().getMachOSection( |
| Segment, Section, TAA, StubSize, SectionKind::getData()); |
| Streamer.SwitchSection(S); |
| Streamer.EmitLabel(getContext(). |
| getOrCreateSymbol(StringRef("L_OBJC_IMAGE_INFO"))); |
| Streamer.EmitIntValue(VersionVal, 4); |
| Streamer.EmitIntValue(ImageInfoFlags, 4); |
| Streamer.AddBlankLine(); |
| } |
| |
| static void checkMachOComdat(const GlobalValue *GV) { |
| const Comdat *C = GV->getComdat(); |
| if (!C) |
| return; |
| |
| report_fatal_error("MachO doesn't support COMDATs, '" + C->getName() + |
| "' cannot be lowered."); |
| } |
| |
| MCSection *TargetLoweringObjectFileMachO::getExplicitSectionGlobal( |
| const GlobalValue *GV, SectionKind Kind, Mangler &Mang, |
| const TargetMachine &TM) const { |
| // Parse the section specifier and create it if valid. |
| StringRef Segment, Section; |
| unsigned TAA = 0, StubSize = 0; |
| bool TAAParsed; |
| |
| checkMachOComdat(GV); |
| |
| std::string ErrorCode = |
| MCSectionMachO::ParseSectionSpecifier(GV->getSection(), Segment, Section, |
| TAA, TAAParsed, StubSize); |
| if (!ErrorCode.empty()) { |
| // If invalid, report the error with report_fatal_error. |
| report_fatal_error("Global variable '" + GV->getName() + |
| "' has an invalid section specifier '" + |
| GV->getSection() + "': " + ErrorCode + "."); |
| } |
| |
| // Get the section. |
| MCSectionMachO *S = |
| getContext().getMachOSection(Segment, Section, TAA, StubSize, Kind); |
| |
| // If TAA wasn't set by ParseSectionSpecifier() above, |
| // use the value returned by getMachOSection() as a default. |
| if (!TAAParsed) |
| TAA = S->getTypeAndAttributes(); |
| |
| // Okay, now that we got the section, verify that the TAA & StubSize agree. |
| // If the user declared multiple globals with different section flags, we need |
| // to reject it here. |
| if (S->getTypeAndAttributes() != TAA || S->getStubSize() != StubSize) { |
| // If invalid, report the error with report_fatal_error. |
| report_fatal_error("Global variable '" + GV->getName() + |
| "' section type or attributes does not match previous" |
| " section specifier"); |
| } |
| |
| return S; |
| } |
| |
| MCSection *TargetLoweringObjectFileMachO::SelectSectionForGlobal( |
| const GlobalValue *GV, SectionKind Kind, Mangler &Mang, |
| const TargetMachine &TM) const { |
| checkMachOComdat(GV); |
| |
| // Handle thread local data. |
| if (Kind.isThreadBSS()) return TLSBSSSection; |
| if (Kind.isThreadData()) return TLSDataSection; |
| |
| if (Kind.isText()) |
| return GV->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 (GV->isWeakForLinker()) { |
| if (Kind.isReadOnly()) |
| return ConstTextCoalSection; |
| return DataCoalSection; |
| } |
| |
| // FIXME: Alignment check should be handled by section classifier. |
| if (Kind.isMergeable1ByteCString() && |
| GV->getParent()->getDataLayout().getPreferredAlignment( |
| cast<GlobalVariable>(GV)) < 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() && !GV->hasExternalLinkage() && |
| GV->getParent()->getDataLayout().getPreferredAlignment( |
| cast<GlobalVariable>(GV)) < 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 (GV->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) const { |
| // If this constant requires a relocation, we have to put it in the data |
| // segment, not in the text segment. |
| if (Kind.isData() || Kind.isReadOnlyWithRel()) |
| return ConstDataSection; |
| |
| if (Kind.isMergeableConst4()) |
| return FourByteConstantSection; |
| if (Kind.isMergeableConst8()) |
| return EightByteConstantSection; |
| if (Kind.isMergeableConst16()) |
| return SixteenByteConstantSection; |
| return ReadOnlySection; // .const |
| } |
| |
| const MCExpr *TargetLoweringObjectFileMachO::getTTypeGlobalReference( |
| const GlobalValue *GV, unsigned Encoding, Mangler &Mang, |
| 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, "$non_lazy_ptr", Mang, TM); |
| |
| // Add information about the stub reference to MachOMMI so that the stub |
| // gets emitted by the asmprinter. |
| MachineModuleInfoImpl::StubValueTy &StubSym = |
| GV->hasHiddenVisibility() ? MachOMMI.getHiddenGVStubEntry(SSym) : |
| MachOMMI.getGVStubEntry(SSym); |
| if (!StubSym.getPointer()) { |
| MCSymbol *Sym = TM.getSymbol(GV, Mang); |
| StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage()); |
| } |
| |
| return TargetLoweringObjectFile:: |
| getTTypeReference(MCSymbolRefExpr::create(SSym, getContext()), |
| Encoding & ~dwarf::DW_EH_PE_indirect, Streamer); |
| } |
| |
| return TargetLoweringObjectFile::getTTypeGlobalReference(GV, Encoding, Mang, |
| TM, MMI, Streamer); |
| } |
| |
| MCSymbol *TargetLoweringObjectFileMachO::getCFIPersonalitySymbol( |
| const GlobalValue *GV, Mangler &Mang, const TargetMachine &TM, |
| MachineModuleInfo *MMI) const { |
| // The mach-o version of this method defaults to returning a stub reference. |
| MachineModuleInfoMachO &MachOMMI = |
| MMI->getObjFileInfo<MachineModuleInfoMachO>(); |
| |
| MCSymbol *SSym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr", Mang, 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, Mang); |
| StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage()); |
| } |
| |
| return SSym; |
| } |
| |
| const MCExpr *TargetLoweringObjectFileMachO::getIndirectSymViaGOTPCRel( |
| const MCSymbol *Sym, const MCValue &MV, int64_t Offset, |
| MachineModuleInfo *MMI, MCStreamer &Streamer) const { |
| // Although MachO 32-bit targets do not explicitly have a GOTPCREL relocation |
| // as 64-bit do, we replace the GOT equivalent by accessing the final symbol |
| // through a non_lazy_ptr stub instead. One advantage is that it allows the |
| // computation of deltas to final external symbols. Example: |
| // |
| // _extgotequiv: |
| // .long _extfoo |
| // |
| // _delta: |
| // .long _extgotequiv-_delta |
| // |
| // is transformed to: |
| // |
| // _delta: |
| // .long L_extfoo$non_lazy_ptr-(_delta+0) |
| // |
| // .section __IMPORT,__pointers,non_lazy_symbol_pointers |
| // L_extfoo$non_lazy_ptr: |
| // .indirect_symbol _extfoo |
| // .long 0 |
| // |
| MachineModuleInfoMachO &MachOMMI = |
| MMI->getObjFileInfo<MachineModuleInfoMachO>(); |
| MCContext &Ctx = getContext(); |
| |
| // The offset must consider the original displacement from the base symbol |
| // since 32-bit targets don't have a GOTPCREL to fold the PC displacement. |
| Offset = -MV.getConstant(); |
| const MCSymbol *BaseSym = &MV.getSymB()->getSymbol(); |
| |
| // Access the final symbol via sym$non_lazy_ptr and generate the appropriated |
| // non_lazy_ptr stubs. |
| SmallString<128> Name; |
| StringRef Suffix = "$non_lazy_ptr"; |
| Name += MMI->getModule()->getDataLayout().getPrivateGlobalPrefix(); |
| Name += Sym->getName(); |
| Name += Suffix; |
| MCSymbol *Stub = Ctx.getOrCreateSymbol(Name); |
| |
| MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(Stub); |
| if (!StubSym.getPointer()) |
| StubSym = MachineModuleInfoImpl:: |
| StubValueTy(const_cast<MCSymbol *>(Sym), true /* access indirectly */); |
| |
| const MCExpr *BSymExpr = |
| MCSymbolRefExpr::create(BaseSym, MCSymbolRefExpr::VK_None, Ctx); |
| const MCExpr *LHS = |
| MCSymbolRefExpr::create(Stub, MCSymbolRefExpr::VK_None, Ctx); |
| |
| if (!Offset) |
| return MCBinaryExpr::createSub(LHS, BSymExpr, Ctx); |
| |
| const MCExpr *RHS = |
| MCBinaryExpr::createAdd(BSymExpr, MCConstantExpr::create(Offset, Ctx), Ctx); |
| return MCBinaryExpr::createSub(LHS, RHS, Ctx); |
| } |
| |
| static bool canUsePrivateLabel(const MCAsmInfo &AsmInfo, |
| const MCSection &Section) { |
| if (!AsmInfo.isSectionAtomizableBySymbols(Section)) |
| return true; |
| |
| // If it is not dead stripped, it is safe to use private labels. |
| const MCSectionMachO &SMO = cast<MCSectionMachO>(Section); |
| if (SMO.hasAttribute(MachO::S_ATTR_NO_DEAD_STRIP)) |
| return true; |
| |
| return false; |
| } |
| |
| void TargetLoweringObjectFileMachO::getNameWithPrefix( |
| SmallVectorImpl<char> &OutName, const GlobalValue *GV, Mangler &Mang, |
| const TargetMachine &TM) const { |
| SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM); |
| const MCSection *TheSection = SectionForGlobal(GV, GVKind, Mang, TM); |
| bool CannotUsePrivateLabel = |
| !canUsePrivateLabel(*TM.getMCAsmInfo(), *TheSection); |
| Mang.getNameWithPrefix(OutName, GV, CannotUsePrivateLabel); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // COFF |
| //===----------------------------------------------------------------------===// |
| |
| static unsigned |
| getCOFFSectionFlags(SectionKind K) { |
| unsigned Flags = 0; |
| |
| if (K.isMetadata()) |
| Flags |= |
| COFF::IMAGE_SCN_MEM_DISCARDABLE; |
| else if (K.isText()) |
| Flags |= |
| COFF::IMAGE_SCN_MEM_EXECUTE | |
| COFF::IMAGE_SCN_MEM_READ | |
| COFF::IMAGE_SCN_CNT_CODE; |
| else if (K.isBSS()) |
| Flags |= |
| COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA | |
| COFF::IMAGE_SCN_MEM_READ | |
| COFF::IMAGE_SCN_MEM_WRITE; |
| else if (K.isThreadLocal()) |
| Flags |= |
| COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | |
| COFF::IMAGE_SCN_MEM_READ | |
| COFF::IMAGE_SCN_MEM_WRITE; |
| else if (K.isReadOnly() || K.isReadOnlyWithRel()) |
| Flags |= |
| COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | |
| COFF::IMAGE_SCN_MEM_READ; |
| else if (K.isWriteable()) |
| Flags |= |
| COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | |
| COFF::IMAGE_SCN_MEM_READ | |
| COFF::IMAGE_SCN_MEM_WRITE; |
| |
| return Flags; |
| } |
| |
| static const GlobalValue *getComdatGVForCOFF(const GlobalValue *GV) { |
| const Comdat *C = GV->getComdat(); |
| assert(C && "expected GV to have a Comdat!"); |
| |
| StringRef ComdatGVName = C->getName(); |
| const GlobalValue *ComdatGV = GV->getParent()->getNamedValue(ComdatGVName); |
| if (!ComdatGV) |
| report_fatal_error("Associative COMDAT symbol '" + ComdatGVName + |
| "' does not exist."); |
| |
| if (ComdatGV->getComdat() != C) |
| report_fatal_error("Associative COMDAT symbol '" + ComdatGVName + |
| "' is not a key for its COMDAT."); |
| |
| return ComdatGV; |
| } |
| |
| static int getSelectionForCOFF(const GlobalValue *GV) { |
| if (const Comdat *C = GV->getComdat()) { |
| const GlobalValue *ComdatKey = getComdatGVForCOFF(GV); |
| if (const auto *GA = dyn_cast<GlobalAlias>(ComdatKey)) |
| ComdatKey = GA->getBaseObject(); |
| if (ComdatKey == GV) { |
| switch (C->getSelectionKind()) { |
| case Comdat::Any: |
| return COFF::IMAGE_COMDAT_SELECT_ANY; |
| case Comdat::ExactMatch: |
| return COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH; |
| case Comdat::Largest: |
| return COFF::IMAGE_COMDAT_SELECT_LARGEST; |
| case Comdat::NoDuplicates: |
| return COFF::IMAGE_COMDAT_SELECT_NODUPLICATES; |
| case Comdat::SameSize: |
| return COFF::IMAGE_COMDAT_SELECT_SAME_SIZE; |
| } |
| } else { |
| return COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE; |
| } |
| } |
| return 0; |
| } |
| |
| MCSection *TargetLoweringObjectFileCOFF::getExplicitSectionGlobal( |
| const GlobalValue *GV, SectionKind Kind, Mangler &Mang, |
| const TargetMachine &TM) const { |
| int Selection = 0; |
| unsigned Characteristics = getCOFFSectionFlags(Kind); |
| StringRef Name = GV->getSection(); |
| StringRef COMDATSymName = ""; |
| if (GV->hasComdat()) { |
| Selection = getSelectionForCOFF(GV); |
| const GlobalValue *ComdatGV; |
| if (Selection == COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE) |
| ComdatGV = getComdatGVForCOFF(GV); |
| else |
| ComdatGV = GV; |
| |
| if (!ComdatGV->hasPrivateLinkage()) { |
| MCSymbol *Sym = TM.getSymbol(ComdatGV, Mang); |
| COMDATSymName = Sym->getName(); |
| Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT; |
| } else { |
| Selection = 0; |
| } |
| } |
| return getContext().getCOFFSection(Name, |
| Characteristics, |
| Kind, |
| COMDATSymName, |
| Selection); |
| } |
| |
| static const char *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 GlobalValue *GV, SectionKind Kind, Mangler &Mang, |
| 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()) || GV->hasComdat()) { |
| const char *Name = getCOFFSectionNameForUniqueGlobal(Kind); |
| unsigned Characteristics = getCOFFSectionFlags(Kind); |
| |
| Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT; |
| int Selection = getSelectionForCOFF(GV); |
| if (!Selection) |
| Selection = COFF::IMAGE_COMDAT_SELECT_NODUPLICATES; |
| const GlobalValue *ComdatGV; |
| if (GV->hasComdat()) |
| ComdatGV = getComdatGVForCOFF(GV); |
| else |
| ComdatGV = GV; |
| |
| if (!ComdatGV->hasPrivateLinkage()) { |
| MCSymbol *Sym = TM.getSymbol(ComdatGV, Mang); |
| StringRef COMDATSymName = Sym->getName(); |
| return getContext().getCOFFSection(Name, Characteristics, Kind, |
| COMDATSymName, Selection); |
| } else { |
| SmallString<256> TmpData; |
| Mang.getNameWithPrefix(TmpData, GV, /*CannotUsePrivateLabel=*/true); |
| return getContext().getCOFFSection(Name, Characteristics, Kind, TmpData, |
| Selection); |
| } |
| } |
| |
| 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, Mangler &Mang, |
| const TargetMachine &TM) const { |
| bool CannotUsePrivateLabel = false; |
| if (GV->hasPrivateLinkage() && |
| ((isa<Function>(GV) && TM.getFunctionSections()) || |
| (isa<GlobalVariable>(GV) && TM.getDataSections()))) |
| CannotUsePrivateLabel = true; |
| |
| Mang.getNameWithPrefix(OutName, GV, CannotUsePrivateLabel); |
| } |
| |
| MCSection *TargetLoweringObjectFileCOFF::getSectionForJumpTable( |
| const Function &F, Mangler &Mang, 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, Mang); |
| StringRef COMDATSymName = Sym->getName(); |
| |
| SectionKind Kind = SectionKind::getReadOnly(); |
| const char *Name = getCOFFSectionNameForUniqueGlobal(Kind); |
| unsigned Characteristics = getCOFFSectionFlags(Kind); |
| Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT; |
| |
| return getContext().getCOFFSection(Name, Characteristics, Kind, COMDATSymName, |
| COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE); |
| } |
| |
| void TargetLoweringObjectFileCOFF:: |
| emitModuleFlags(MCStreamer &Streamer, |
| ArrayRef<Module::ModuleFlagEntry> ModuleFlags, |
| Mangler &Mang, const TargetMachine &TM) const { |
| MDNode *LinkerOptions = nullptr; |
| |
| // Look for the "Linker Options" flag, since it's the only one we support. |
| for (ArrayRef<Module::ModuleFlagEntry>::iterator |
| i = ModuleFlags.begin(), e = ModuleFlags.end(); i != e; ++i) { |
| const Module::ModuleFlagEntry &MFE = *i; |
| StringRef Key = MFE.Key->getString(); |
| Metadata *Val = MFE.Val; |
| if (Key == "Linker Options") { |
| LinkerOptions = cast<MDNode>(Val); |
| break; |
| } |
| } |
| if (!LinkerOptions) |
| return; |
| |
| // 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 (unsigned i = 0, e = LinkerOptions->getNumOperands(); i != e; ++i) { |
| MDNode *MDOptions = cast<MDNode>(LinkerOptions->getOperand(i)); |
| for (unsigned ii = 0, ie = MDOptions->getNumOperands(); ii != ie; ++ii) { |
| MDString *MDOption = cast<MDString>(MDOptions->getOperand(ii)); |
| // Lead with a space for consistency with our dllexport implementation. |
| std::string Directive(" "); |
| Directive.append(MDOption->getString()); |
| Streamer.EmitBytes(Directive); |
| } |
| } |
| } |
| |
| MCSection *TargetLoweringObjectFileCOFF::getStaticCtorSection( |
| unsigned Priority, const MCSymbol *KeySym) const { |
| return getContext().getAssociativeCOFFSection( |
| cast<MCSectionCOFF>(StaticCtorSection), KeySym); |
| } |
| |
| MCSection *TargetLoweringObjectFileCOFF::getStaticDtorSection( |
| unsigned Priority, const MCSymbol *KeySym) const { |
| return getContext().getAssociativeCOFFSection( |
| cast<MCSectionCOFF>(StaticDtorSection), KeySym); |
| } |
| |
| void TargetLoweringObjectFileCOFF::emitLinkerFlagsForGlobal( |
| raw_ostream &OS, const GlobalValue *GV, const Mangler &Mang) const { |
| if (!GV->hasDLLExportStorageClass() || GV->isDeclaration()) |
| return; |
| |
| const Triple &TT = getTargetTriple(); |
| |
| if (TT.isKnownWindowsMSVCEnvironment()) |
| OS << " /EXPORT:"; |
| else |
| OS << " -export:"; |
| |
| if (TT.isWindowsGNUEnvironment() || TT.isWindowsCygwinEnvironment()) { |
| std::string Flag; |
| raw_string_ostream FlagOS(Flag); |
| Mang.getNameWithPrefix(FlagOS, GV, false); |
| FlagOS.flush(); |
| if (Flag[0] == GV->getParent()->getDataLayout().getGlobalPrefix()) |
| OS << Flag.substr(1); |
| else |
| OS << Flag; |
| } else { |
| Mang.getNameWithPrefix(OS, GV, false); |
| } |
| |
| if (!GV->getValueType()->isFunctionTy()) { |
| if (TT.isKnownWindowsMSVCEnvironment()) |
| OS << ",DATA"; |
| else |
| OS << ",data"; |
| } |
| } |