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Diffstat (limited to 'contrib/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp | 1047 |
1 files changed, 1047 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/contrib/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp new file mode 100644 index 0000000..d7b043d --- /dev/null +++ b/contrib/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp @@ -0,0 +1,1047 @@ +//===-- 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/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/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 TargetMachine &TM, + 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 = 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, 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.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"; +} + +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 = + TM.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(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; + + if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection; + 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; +} + +/// getDepLibFromLinkerOpt - Extract the dependent library name from a linker +/// option string. Returns StringRef() if the option does not specify a library. +StringRef TargetLoweringObjectFileMachO:: +getDepLibFromLinkerOpt(StringRef LinkerOption) const { + const char *LibCmd = "-l"; + if (LinkerOption.startswith(LibCmd)) + return LinkerOption.substr(strlen(LibCmd)); + return StringRef(); +} + +/// 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::getDataNoRel()); + 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() && + 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; + + // 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(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.isDataRel() || 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 explictly 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 += DL->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); +} + +//===----------------------------------------------------------------------===// +// 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; + } + } else if (GV->isWeakForLinker()) { + return COFF::IMAGE_COMDAT_SELECT_ANY; + } + 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; + getNameWithPrefix(TmpData, GV, /*CannotUsePrivateLabel=*/true, Mang, TM); + 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, + bool CannotUsePrivateLabel, Mangler &Mang, const TargetMachine &TM) const { + 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); +} + +StringRef TargetLoweringObjectFileCOFF:: +getDepLibFromLinkerOpt(StringRef LinkerOption) const { + const char *LibCmd = "/DEFAULTLIB:"; + if (LinkerOption.startswith(LibCmd)) + return LinkerOption.substr(strlen(LibCmd)); + return StringRef(); +} + +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); +} |
