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Diffstat (limited to 'contrib/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp | 716 |
1 files changed, 716 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..9925185 --- /dev/null +++ b/contrib/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp @@ -0,0 +1,716 @@ +//===-- 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/Constants.h" +#include "llvm/DerivedTypes.h" +#include "llvm/Function.h" +#include "llvm/GlobalVariable.h" +#include "llvm/Module.h" +#include "llvm/CodeGen/MachineModuleInfoImpls.h" +#include "llvm/MC/MCContext.h" +#include "llvm/MC/MCExpr.h" +#include "llvm/MC/MCSectionMachO.h" +#include "llvm/MC/MCSectionELF.h" +#include "llvm/MC/MCSectionCOFF.h" +#include "llvm/MC/MCStreamer.h" +#include "llvm/MC/MCSymbol.h" +#include "llvm/Target/Mangler.h" +#include "llvm/Target/TargetData.h" +#include "llvm/Target/TargetMachine.h" +#include "llvm/Target/TargetOptions.h" +#include "llvm/Support/Dwarf.h" +#include "llvm/Support/ELF.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/ADT/SmallString.h" +#include "llvm/ADT/StringExtras.h" +#include "llvm/ADT/Triple.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.getTargetData()->getPointerSize(); + Streamer.SwitchSection(Sec); + Streamer.EmitValueToAlignment(TM.getTargetData()->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); +} + +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.getTargetData()->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 MCExpr *TargetLoweringObjectFileELF:: +getExprForDwarfGlobalReference(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:: + getExprForDwarfReference(SSym, Encoding & ~dwarf::DW_EH_PE_indirect, Streamer); + } + + return TargetLoweringObjectFile:: + getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer); +} + +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; + + 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; + + std::string Name = std::string(".dtors.") + utostr(65535 - Priority); + return getContext().getELFSection(Name, ELF::SHT_PROGBITS, + ELF::SHF_ALLOC |ELF::SHF_WRITE, + SectionKind::getDataRel()); +} + +//===----------------------------------------------------------------------===// +// MachO +//===----------------------------------------------------------------------===// + +/// emitModuleFlags - Emit the module flags that specify the garbage collection +/// information. +void TargetLoweringObjectFileMachO:: +emitModuleFlags(MCStreamer &Streamer, + ArrayRef<Module::ModuleFlagEntry> ModuleFlags, + Mangler *Mang, const TargetMachine &TM) const { + unsigned VersionVal = 0; + unsigned GCFlags = 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") + GCFlags |= cast<ConstantInt>(Val)->getZExtValue(); + else if (Key == "Objective-C Image Info Section") + SectionVal = cast<MDString>(Val)->getString(); + } + + // 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(GCFlags, 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.getTargetData()->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.getTargetData()->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:: +getExprForDwarfGlobalReference(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 += "$non_lazy_ptr"; + + // Add information about the stub reference to MachOMMI so that the stub + // gets emitted by the asmprinter. + MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str()); + MachineModuleInfoImpl::StubValueTy &StubSym = + GV->hasHiddenVisibility() ? MachOMMI.getHiddenGVStubEntry(SSym) : + MachOMMI.getGVStubEntry(SSym); + if (StubSym.getPointer() == 0) { + MCSymbol *Sym = Mang->getSymbol(GV); + StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage()); + } + + return TargetLoweringObjectFile:: + getExprForDwarfReference(SSym, Encoding & ~dwarf::DW_EH_PE_indirect, Streamer); + } + + return TargetLoweringObjectFile:: + getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer); +} + +MCSymbol *TargetLoweringObjectFileMachO:: +getCFIPersonalitySymbol(const GlobalValue *GV, Mangler *Mang, + MachineModuleInfo *MMI) const { + // The mach-o version of this method defaults to returning a stub reference. + MachineModuleInfoMachO &MachOMMI = + MMI->getObjFileInfo<MachineModuleInfoMachO>(); + + SmallString<128> Name; + Mang->getNameWithPrefix(Name, GV, true); + Name += "$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 { + return getContext().getCOFFSection(GV->getSection(), + getCOFFSectionFlags(Kind), + Kind); +} + +static const char *getCOFFSectionPrefixForUniqueGlobal(SectionKind Kind) { + if (Kind.isText()) + return ".text$"; + if (Kind.isBSS ()) + return ".bss$"; + if (Kind.isThreadLocal()) + return ".tls$"; + if (Kind.isWriteable()) + return ".data$"; + 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(); +} + |
