| //===-- 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/Module.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/MCSymbol.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/Mangler.h" |
| #include "llvm/Target/TargetMachine.h" |
| using namespace llvm; |
| using namespace dwarf; |
| |
| //===----------------------------------------------------------------------===// |
| // ELF |
| //===----------------------------------------------------------------------===// |
| |
| MCSymbol * |
| TargetLoweringObjectFileELF::getCFIPersonalitySymbol(const GlobalValue *GV, |
| Mangler *Mang, |
| MachineModuleInfo *MMI) const { |
| unsigned Encoding = getPersonalityEncoding(); |
| switch (Encoding & 0x70) { |
| default: |
| report_fatal_error("We do not support this DWARF encoding yet!"); |
| case dwarf::DW_EH_PE_absptr: |
| return Mang->getSymbol(GV); |
| case dwarf::DW_EH_PE_pcrel: { |
| return getContext().GetOrCreateSymbol(StringRef("DW.ref.") + |
| Mang->getSymbol(GV)->getName()); |
| } |
| } |
| } |
| |
| void TargetLoweringObjectFileELF::emitPersonalityValue(MCStreamer &Streamer, |
| const TargetMachine &TM, |
| const MCSymbol *Sym) const { |
| SmallString<64> NameData("DW.ref."); |
| NameData += Sym->getName(); |
| MCSymbol *Label = 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; |
| const MCSection *Sec = getContext().getELFSection(NameData, |
| ELF::SHT_PROGBITS, |
| Flags, |
| SectionKind::getDataRel(), |
| 0, Label->getName()); |
| unsigned Size = TM.getDataLayout()->getPointerSize(); |
| Streamer.SwitchSection(Sec); |
| Streamer.EmitValueToAlignment(TM.getDataLayout()->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, Mangler *Mang, |
| MachineModuleInfo *MMI, unsigned Encoding, |
| MCStreamer &Streamer) const { |
| |
| if (Encoding & dwarf::DW_EH_PE_indirect) { |
| MachineModuleInfoELF &ELFMMI = MMI->getObjFileInfo<MachineModuleInfoELF>(); |
| |
| SmallString<128> Name; |
| Mang->getNameWithPrefix(Name, GV, true); |
| Name += ".DW.stub"; |
| |
| // Add information about the stub reference to ELFMMI so that the stub |
| // gets emitted by the asmprinter. |
| MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str()); |
| MachineModuleInfoImpl::StubValueTy &StubSym = ELFMMI.getGVStubEntry(SSym); |
| if (StubSym.getPointer() == 0) { |
| MCSymbol *Sym = Mang->getSymbol(GV); |
| StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage()); |
| } |
| |
| return TargetLoweringObjectFile:: |
| getTTypeReference(MCSymbolRefExpr::Create(SSym, getContext()), |
| Encoding & ~dwarf::DW_EH_PE_indirect, Streamer); |
| } |
| |
| return TargetLoweringObjectFile:: |
| getTTypeGlobalReference(GV, Mang, MMI, Encoding, 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; |
| |
| // K.isMergeableConst() is left out to honour PR4650 |
| if (K.isMergeableCString() || K.isMergeableConst4() || |
| K.isMergeableConst8() || K.isMergeableConst16()) |
| Flags |= ELF::SHF_MERGE; |
| |
| if (K.isMergeableCString()) |
| Flags |= ELF::SHF_STRINGS; |
| |
| return Flags; |
| } |
| |
| |
| const 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); |
| |
| return getContext().getELFSection(SectionName, |
| getELFSectionType(SectionName, Kind), |
| getELFSectionFlags(Kind), Kind); |
| } |
| |
| /// getSectionPrefixForGlobal - Return the section prefix name used by options |
| /// FunctionsSections and DataSections. |
| static const char *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.isDataNoRel()) return ".data."; |
| if (Kind.isDataRelLocal()) return ".data.rel.local."; |
| if (Kind.isDataRel()) return ".data.rel."; |
| if (Kind.isReadOnlyWithRelLocal()) return ".data.rel.ro.local."; |
| |
| assert(Kind.isReadOnlyWithRel() && "Unknown section kind"); |
| return ".data.rel.ro."; |
| } |
| |
| |
| const MCSection *TargetLoweringObjectFileELF:: |
| SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind, |
| Mangler *Mang, const TargetMachine &TM) const { |
| // If we have -ffunction-section or -fdata-section 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 this global is linkonce/weak and the target handles this by emitting it |
| // into a 'uniqued' section name, create and return the section now. |
| if ((GV->isWeakForLinker() || EmitUniquedSection) && |
| !Kind.isCommon()) { |
| const char *Prefix; |
| Prefix = getSectionPrefixForGlobal(Kind); |
| |
| SmallString<128> Name(Prefix, Prefix+strlen(Prefix)); |
| MCSymbol *Sym = Mang->getSymbol(GV); |
| Name.append(Sym->getName().begin(), Sym->getName().end()); |
| StringRef Group = ""; |
| unsigned Flags = getELFSectionFlags(Kind); |
| if (GV->isWeakForLinker()) { |
| Group = Sym->getName(); |
| Flags |= ELF::SHF_GROUP; |
| } |
| |
| return getContext().getELFSection(Name.str(), |
| getELFSectionType(Name.str(), Kind), |
| Flags, Kind, 0, Group); |
| } |
| |
| if (Kind.isText()) return TextSection; |
| |
| if (Kind.isMergeable1ByteCString() || |
| Kind.isMergeable2ByteCString() || |
| Kind.isMergeable4ByteCString()) { |
| |
| // We also need alignment here. |
| // FIXME: this is getting the alignment of the character, not the |
| // alignment of the global! |
| unsigned Align = |
| TM.getDataLayout()->getPreferredAlignment(cast<GlobalVariable>(GV)); |
| |
| const char *SizeSpec = ".rodata.str1."; |
| if (Kind.isMergeable2ByteCString()) |
| SizeSpec = ".rodata.str2."; |
| else if (Kind.isMergeable4ByteCString()) |
| SizeSpec = ".rodata.str4."; |
| else |
| assert(Kind.isMergeable1ByteCString() && "unknown string width"); |
| |
| |
| std::string Name = SizeSpec + utostr(Align); |
| return getContext().getELFSection(Name, ELF::SHT_PROGBITS, |
| ELF::SHF_ALLOC | |
| ELF::SHF_MERGE | |
| ELF::SHF_STRINGS, |
| Kind); |
| } |
| |
| if (Kind.isMergeableConst()) { |
| if (Kind.isMergeableConst4() && MergeableConst4Section) |
| return MergeableConst4Section; |
| if (Kind.isMergeableConst8() && MergeableConst8Section) |
| return MergeableConst8Section; |
| if (Kind.isMergeableConst16() && MergeableConst16Section) |
| return MergeableConst16Section; |
| return ReadOnlySection; // .const |
| } |
| |
| if (Kind.isReadOnly()) return ReadOnlySection; |
| |
| if (Kind.isThreadData()) return TLSDataSection; |
| if (Kind.isThreadBSS()) return TLSBSSSection; |
| |
| // 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; |
| |
| if (Kind.isDataNoRel()) return DataSection; |
| if (Kind.isDataRelLocal()) return DataRelLocalSection; |
| if (Kind.isDataRel()) return DataRelSection; |
| if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection; |
| |
| assert(Kind.isReadOnlyWithRel() && "Unknown section kind"); |
| return DataRelROSection; |
| } |
| |
| /// getSectionForConstant - Given a mergeable constant with the |
| /// specified size and relocation information, return a section that it |
| /// should be placed in. |
| const MCSection *TargetLoweringObjectFileELF:: |
| getSectionForConstant(SectionKind Kind) const { |
| if (Kind.isMergeableConst4() && MergeableConst4Section) |
| return MergeableConst4Section; |
| if (Kind.isMergeableConst8() && MergeableConst8Section) |
| return MergeableConst8Section; |
| if (Kind.isMergeableConst16() && MergeableConst16Section) |
| return MergeableConst16Section; |
| if (Kind.isReadOnly()) |
| return ReadOnlySection; |
| |
| if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection; |
| assert(Kind.isReadOnlyWithRel() && "Unknown section kind"); |
| return DataRelROSection; |
| } |
| |
| const MCSection * |
| TargetLoweringObjectFileELF::getStaticCtorSection(unsigned Priority) const { |
| // The default scheme is .ctor / .dtor, so we have to invert the priority |
| // numbering. |
| if (Priority == 65535) |
| return StaticCtorSection; |
| |
| if (UseInitArray) { |
| std::string Name = std::string(".init_array.") + utostr(Priority); |
| return getContext().getELFSection(Name, ELF::SHT_INIT_ARRAY, |
| ELF::SHF_ALLOC | ELF::SHF_WRITE, |
| SectionKind::getDataRel()); |
| } else { |
| std::string Name = std::string(".ctors.") + utostr(65535 - Priority); |
| return getContext().getELFSection(Name, ELF::SHT_PROGBITS, |
| ELF::SHF_ALLOC |ELF::SHF_WRITE, |
| SectionKind::getDataRel()); |
| } |
| } |
| |
| const MCSection * |
| TargetLoweringObjectFileELF::getStaticDtorSection(unsigned Priority) const { |
| // The default scheme is .ctor / .dtor, so we have to invert the priority |
| // numbering. |
| if (Priority == 65535) |
| return StaticDtorSection; |
| |
| if (UseInitArray) { |
| std::string Name = std::string(".fini_array.") + utostr(Priority); |
| return getContext().getELFSection(Name, ELF::SHT_FINI_ARRAY, |
| ELF::SHF_ALLOC | ELF::SHF_WRITE, |
| SectionKind::getDataRel()); |
| } else { |
| std::string Name = std::string(".dtors.") + utostr(65535 - Priority); |
| return getContext().getELFSection(Name, ELF::SHT_PROGBITS, |
| ELF::SHF_ALLOC |ELF::SHF_WRITE, |
| SectionKind::getDataRel()); |
| } |
| } |
| |
| 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, |
| SectionKind::getDataRel()); |
| StaticDtorSection = |
| getContext().getELFSection(".fini_array", ELF::SHT_FINI_ARRAY, |
| ELF::SHF_WRITE | |
| ELF::SHF_ALLOC, |
| SectionKind::getDataRel()); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // MachO |
| //===----------------------------------------------------------------------===// |
| |
| /// 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 = 0; |
| 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(); |
| Value *Val = MFE.Val; |
| |
| if (Key == "Objective-C Image Info Version") { |
| VersionVal = cast<ConstantInt>(Val)->getZExtValue(); |
| } else if (Key == "Objective-C Garbage Collection" || |
| Key == "Objective-C GC Only" || |
| Key == "Objective-C Is Simulated") { |
| ImageInfoFlags |= cast<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. |
| const MCSectionMachO *S = |
| getContext().getMachOSection(Segment, Section, TAA, StubSize, |
| SectionKind::getDataNoRel()); |
| Streamer.SwitchSection(S); |
| Streamer.EmitLabel(getContext(). |
| GetOrCreateSymbol(StringRef("L_OBJC_IMAGE_INFO"))); |
| Streamer.EmitIntValue(VersionVal, 4); |
| Streamer.EmitIntValue(ImageInfoFlags, 4); |
| Streamer.AddBlankLine(); |
| } |
| |
| const 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; |
| 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. |
| const 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; |
| } |
| |
| const MCSection *TargetLoweringObjectFileMachO:: |
| SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind, |
| Mangler *Mang, const TargetMachine &TM) const { |
| |
| // 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() && |
| TM.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() && |
| TM.getDataLayout()->getPreferredAlignment(cast<GlobalVariable>(GV)) < 32) |
| return UStringSection; |
| |
| if (Kind.isMergeableConst()) { |
| if (Kind.isMergeableConst4()) |
| return FourByteConstantSection; |
| if (Kind.isMergeableConst8()) |
| return EightByteConstantSection; |
| if (Kind.isMergeableConst16() && SixteenByteConstantSection) |
| 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; |
| } |
| |
| const MCSection * |
| TargetLoweringObjectFileMachO::getSectionForConstant(SectionKind Kind) const { |
| // If this constant requires a relocation, we have to put it in the data |
| // segment, not in the text segment. |
| if (Kind.isDataRel() || Kind.isReadOnlyWithRel()) |
| return ConstDataSection; |
| |
| if (Kind.isMergeableConst4()) |
| return FourByteConstantSection; |
| if (Kind.isMergeableConst8()) |
| return EightByteConstantSection; |
| if (Kind.isMergeableConst16() && SixteenByteConstantSection) |
| return SixteenByteConstantSection; |
| return ReadOnlySection; // .const |
| } |
| |
| /// shouldEmitUsedDirectiveFor - This hook allows targets to selectively decide |
| /// not to emit the UsedDirective for some symbols in llvm.used. |
| // FIXME: REMOVE this (rdar://7071300) |
| bool TargetLoweringObjectFileMachO:: |
| shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler *Mang) const { |
| /// On Darwin, internally linked data beginning with "L" or "l" does not have |
| /// the directive emitted (this occurs in ObjC metadata). |
| if (!GV) return false; |
| |
| // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix. |
| if (GV->hasLocalLinkage() && !isa<Function>(GV)) { |
| // FIXME: ObjC metadata is currently emitted as internal symbols that have |
| // \1L and \0l prefixes on them. Fix them to be Private/LinkerPrivate and |
| // this horrible hack can go away. |
| MCSymbol *Sym = Mang->getSymbol(GV); |
| if (Sym->getName()[0] == 'L' || Sym->getName()[0] == 'l') |
| return false; |
| } |
| |
| return true; |
| } |
| |
| const MCExpr *TargetLoweringObjectFileMachO:: |
| getTTypeGlobalReference(const GlobalValue *GV, Mangler *Mang, |
| MachineModuleInfo *MMI, unsigned Encoding, |
| 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>(); |
| |
| SmallString<128> Name; |
| Mang->getNameWithPrefix(Name, GV, true); |
| Name += "$non_lazy_ptr"; |
| |
| // Add information about the stub reference to MachOMMI so that the stub |
| // gets emitted by the asmprinter. |
| MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str()); |
| MachineModuleInfoImpl::StubValueTy &StubSym = |
| GV->hasHiddenVisibility() ? MachOMMI.getHiddenGVStubEntry(SSym) : |
| MachOMMI.getGVStubEntry(SSym); |
| if (StubSym.getPointer() == 0) { |
| MCSymbol *Sym = Mang->getSymbol(GV); |
| StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage()); |
| } |
| |
| return TargetLoweringObjectFile:: |
| getTTypeReference(MCSymbolRefExpr::Create(SSym, getContext()), |
| Encoding & ~dwarf::DW_EH_PE_indirect, Streamer); |
| } |
| |
| return TargetLoweringObjectFile:: |
| getTTypeGlobalReference(GV, Mang, MMI, Encoding, Streamer); |
| } |
| |
| MCSymbol *TargetLoweringObjectFileMachO:: |
| getCFIPersonalitySymbol(const GlobalValue *GV, Mangler *Mang, |
| MachineModuleInfo *MMI) const { |
| // The mach-o version of this method defaults to returning a stub reference. |
| MachineModuleInfoMachO &MachOMMI = |
| MMI->getObjFileInfo<MachineModuleInfoMachO>(); |
| |
| SmallString<128> Name; |
| Mang->getNameWithPrefix(Name, GV, true); |
| Name += "$non_lazy_ptr"; |
| |
| // Add information about the stub reference to MachOMMI so that the stub |
| // gets emitted by the asmprinter. |
| MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str()); |
| MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(SSym); |
| if (StubSym.getPointer() == 0) { |
| MCSymbol *Sym = Mang->getSymbol(GV); |
| StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage()); |
| } |
| |
| return SSym; |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // 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()) |
| 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; |
| } |
| |
| const MCSection *TargetLoweringObjectFileCOFF:: |
| getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind, |
| Mangler *Mang, const TargetMachine &TM) const { |
| int Selection = 0; |
| unsigned Characteristics = getCOFFSectionFlags(Kind); |
| SmallString<128> Name(GV->getSection().c_str()); |
| if (GV->isWeakForLinker()) { |
| Selection = COFF::IMAGE_COMDAT_SELECT_ANY; |
| Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT; |
| MCSymbol *Sym = Mang->getSymbol(GV); |
| Name.append("$"); |
| Name.append(Sym->getName().begin() + 1, Sym->getName().end()); |
| } |
| return getContext().getCOFFSection(Name, |
| Characteristics, |
| Selection, |
| Kind); |
| } |
| |
| static const char *getCOFFSectionPrefixForUniqueGlobal(SectionKind Kind) { |
| if (Kind.isText()) |
| return ".text$"; |
| if (Kind.isBSS ()) |
| return ".bss$"; |
| if (Kind.isThreadLocal()) { |
| // 'LLVM' is just an arbitary string to ensure that the section name gets |
| // sorted in between '.tls$AAA' and '.tls$ZZZ' by the linker. |
| return ".tls$LLVM"; |
| } |
| if (Kind.isWriteable()) |
| return ".data$"; |
| return ".rdata$"; |
| } |
| |
| |
| const MCSection *TargetLoweringObjectFileCOFF:: |
| SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind, |
| Mangler *Mang, const TargetMachine &TM) const { |
| |
| // If this global is linkonce/weak and the target handles this by emitting it |
| // into a 'uniqued' section name, create and return the section now. |
| if (GV->isWeakForLinker()) { |
| const char *Prefix = getCOFFSectionPrefixForUniqueGlobal(Kind); |
| SmallString<128> Name(Prefix, Prefix+strlen(Prefix)); |
| MCSymbol *Sym = Mang->getSymbol(GV); |
| Name.append(Sym->getName().begin() + 1, Sym->getName().end()); |
| |
| unsigned Characteristics = getCOFFSectionFlags(Kind); |
| |
| Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT; |
| |
| return getContext().getCOFFSection(Name.str(), Characteristics, |
| COFF::IMAGE_COMDAT_SELECT_ANY, Kind); |
| } |
| |
| if (Kind.isText()) |
| return getTextSection(); |
| |
| if (Kind.isThreadLocal()) |
| return getTLSDataSection(); |
| |
| return getDataSection(); |
| } |
| |
