//===-- 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/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/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/ErrorHandling.h" #include "llvm/Support/raw_ostream.h" #include "llvm/ADT/SmallString.h" #include "llvm/ADT/StringExtras.h" using namespace llvm; using namespace dwarf; //===----------------------------------------------------------------------===// // ELF //===----------------------------------------------------------------------===// void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx, const TargetMachine &TM) { TargetLoweringObjectFile::Initialize(Ctx, TM); BSSSection = getContext().getELFSection(".bss", MCSectionELF::SHT_NOBITS, MCSectionELF::SHF_WRITE |MCSectionELF::SHF_ALLOC, SectionKind::getBSS()); TextSection = getContext().getELFSection(".text", MCSectionELF::SHT_PROGBITS, MCSectionELF::SHF_EXECINSTR | MCSectionELF::SHF_ALLOC, SectionKind::getText()); DataSection = getContext().getELFSection(".data", MCSectionELF::SHT_PROGBITS, MCSectionELF::SHF_WRITE |MCSectionELF::SHF_ALLOC, SectionKind::getDataRel()); ReadOnlySection = getContext().getELFSection(".rodata", MCSectionELF::SHT_PROGBITS, MCSectionELF::SHF_ALLOC, SectionKind::getReadOnly()); TLSDataSection = getContext().getELFSection(".tdata", MCSectionELF::SHT_PROGBITS, MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_TLS | MCSectionELF::SHF_WRITE, SectionKind::getThreadData()); TLSBSSSection = getContext().getELFSection(".tbss", MCSectionELF::SHT_NOBITS, MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_TLS | MCSectionELF::SHF_WRITE, SectionKind::getThreadBSS()); DataRelSection = getContext().getELFSection(".data.rel", MCSectionELF::SHT_PROGBITS, MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_WRITE, SectionKind::getDataRel()); DataRelLocalSection = getContext().getELFSection(".data.rel.local", MCSectionELF::SHT_PROGBITS, MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_WRITE, SectionKind::getDataRelLocal()); DataRelROSection = getContext().getELFSection(".data.rel.ro", MCSectionELF::SHT_PROGBITS, MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_WRITE, SectionKind::getReadOnlyWithRel()); DataRelROLocalSection = getContext().getELFSection(".data.rel.ro.local", MCSectionELF::SHT_PROGBITS, MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_WRITE, SectionKind::getReadOnlyWithRelLocal()); MergeableConst4Section = getContext().getELFSection(".rodata.cst4", MCSectionELF::SHT_PROGBITS, MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_MERGE, SectionKind::getMergeableConst4()); MergeableConst8Section = getContext().getELFSection(".rodata.cst8", MCSectionELF::SHT_PROGBITS, MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_MERGE, SectionKind::getMergeableConst8()); MergeableConst16Section = getContext().getELFSection(".rodata.cst16", MCSectionELF::SHT_PROGBITS, MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_MERGE, SectionKind::getMergeableConst16()); StaticCtorSection = getContext().getELFSection(".ctors", MCSectionELF::SHT_PROGBITS, MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_WRITE, SectionKind::getDataRel()); StaticDtorSection = getContext().getELFSection(".dtors", MCSectionELF::SHT_PROGBITS, MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_WRITE, SectionKind::getDataRel()); // Exception Handling Sections. // FIXME: We're emitting LSDA info into a readonly section on ELF, even though // it contains relocatable pointers. In PIC mode, this is probably a big // runtime hit for C++ apps. Either the contents of the LSDA need to be // adjusted or this should be a data section. LSDASection = getContext().getELFSection(".gcc_except_table", MCSectionELF::SHT_PROGBITS, MCSectionELF::SHF_ALLOC, SectionKind::getReadOnly()); EHFrameSection = getContext().getELFSection(".eh_frame", MCSectionELF::SHT_PROGBITS, MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_WRITE, SectionKind::getDataRel()); // Debug Info Sections. DwarfAbbrevSection = getContext().getELFSection(".debug_abbrev", MCSectionELF::SHT_PROGBITS, 0, SectionKind::getMetadata()); DwarfInfoSection = getContext().getELFSection(".debug_info", MCSectionELF::SHT_PROGBITS, 0, SectionKind::getMetadata()); DwarfLineSection = getContext().getELFSection(".debug_line", MCSectionELF::SHT_PROGBITS, 0, SectionKind::getMetadata()); DwarfFrameSection = getContext().getELFSection(".debug_frame", MCSectionELF::SHT_PROGBITS, 0, SectionKind::getMetadata()); DwarfPubNamesSection = getContext().getELFSection(".debug_pubnames", MCSectionELF::SHT_PROGBITS, 0, SectionKind::getMetadata()); DwarfPubTypesSection = getContext().getELFSection(".debug_pubtypes", MCSectionELF::SHT_PROGBITS, 0, SectionKind::getMetadata()); DwarfStrSection = getContext().getELFSection(".debug_str", MCSectionELF::SHT_PROGBITS, 0, SectionKind::getMetadata()); DwarfLocSection = getContext().getELFSection(".debug_loc", MCSectionELF::SHT_PROGBITS, 0, SectionKind::getMetadata()); DwarfARangesSection = getContext().getELFSection(".debug_aranges", MCSectionELF::SHT_PROGBITS, 0, SectionKind::getMetadata()); DwarfRangesSection = getContext().getELFSection(".debug_ranges", MCSectionELF::SHT_PROGBITS, 0, SectionKind::getMetadata()); DwarfMacroInfoSection = getContext().getELFSection(".debug_macinfo", MCSectionELF::SHT_PROGBITS, 0, SectionKind::getMetadata()); } static SectionKind getELFKindForNamedSection(StringRef Name, SectionKind K) { 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 MCSectionELF::SHT_INIT_ARRAY; if (Name == ".fini_array") return MCSectionELF::SHT_FINI_ARRAY; if (Name == ".preinit_array") return MCSectionELF::SHT_PREINIT_ARRAY; if (K.isBSS() || K.isThreadBSS()) return MCSectionELF::SHT_NOBITS; return MCSectionELF::SHT_PROGBITS; } static unsigned getELFSectionFlags(SectionKind K) { unsigned Flags = 0; if (!K.isMetadata()) Flags |= MCSectionELF::SHF_ALLOC; if (K.isText()) Flags |= MCSectionELF::SHF_EXECINSTR; if (K.isWriteable()) Flags |= MCSectionELF::SHF_WRITE; if (K.isThreadLocal()) Flags |= MCSectionELF::SHF_TLS; // K.isMergeableConst() is left out to honour PR4650 if (K.isMergeableCString() || K.isMergeableConst4() || K.isMergeableConst8() || K.isMergeableConst16()) Flags |= MCSectionELF::SHF_MERGE; if (K.isMergeableCString()) Flags |= MCSectionELF::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, true); } static const char *getSectionPrefixForUniqueGlobal(SectionKind Kind) { if (Kind.isText()) return ".gnu.linkonce.t."; if (Kind.isReadOnly()) return ".gnu.linkonce.r."; if (Kind.isThreadData()) return ".gnu.linkonce.td."; if (Kind.isThreadBSS()) return ".gnu.linkonce.tb."; if (Kind.isDataNoRel()) return ".gnu.linkonce.d."; if (Kind.isDataRelLocal()) return ".gnu.linkonce.d.rel.local."; if (Kind.isDataRel()) return ".gnu.linkonce.d.rel."; if (Kind.isReadOnlyWithRelLocal()) return ".gnu.linkonce.d.rel.ro.local."; assert(Kind.isReadOnlyWithRel() && "Unknown section kind"); return ".gnu.linkonce.d.rel.ro."; } /// 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.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() && !Kind.isBSS()) { const char *Prefix; if (GV->isWeakForLinker()) Prefix = getSectionPrefixForUniqueGlobal(Kind); else { assert(EmitUniquedSection); Prefix = getSectionPrefixForGlobal(Kind); } SmallString<128> Name(Prefix, Prefix+strlen(Prefix)); MCSymbol *Sym = Mang->getSymbol(GV); Name.append(Sym->getName().begin(), Sym->getName().end()); return getContext().getELFSection(Name.str(), getELFSectionType(Name.str(), Kind), getELFSectionFlags(Kind), Kind); } 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(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, MCSectionELF::SHT_PROGBITS, MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_MERGE | MCSectionELF::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(); 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, Mang, MMI, Encoding & ~dwarf::DW_EH_PE_indirect, Streamer); } return TargetLoweringObjectFile:: getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer); } //===----------------------------------------------------------------------===// // MachO //===----------------------------------------------------------------------===// void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx, const TargetMachine &TM) { // _foo.eh symbols are currently always exported so that the linker knows // about them. This is not necessary on 10.6 and later, but it // doesn't hurt anything. // FIXME: I need to get this from Triple. IsFunctionEHSymbolGlobal = true; IsFunctionEHFrameSymbolPrivate = false; SupportsWeakOmittedEHFrame = false; TargetLoweringObjectFile::Initialize(Ctx, TM); TextSection // .text = getContext().getMachOSection("__TEXT", "__text", MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS, SectionKind::getText()); DataSection // .data = getContext().getMachOSection("__DATA", "__data", 0, SectionKind::getDataRel()); TLSDataSection // .tdata = getContext().getMachOSection("__DATA", "__thread_data", MCSectionMachO::S_THREAD_LOCAL_REGULAR, SectionKind::getDataRel()); TLSBSSSection // .tbss = getContext().getMachOSection("__DATA", "__thread_bss", MCSectionMachO::S_THREAD_LOCAL_ZEROFILL, SectionKind::getThreadBSS()); // TODO: Verify datarel below. TLSTLVSection // .tlv = getContext().getMachOSection("__DATA", "__thread_vars", MCSectionMachO::S_THREAD_LOCAL_VARIABLES, SectionKind::getDataRel()); TLSThreadInitSection = getContext().getMachOSection("__DATA", "__thread_init", MCSectionMachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS, SectionKind::getDataRel()); CStringSection // .cstring = getContext().getMachOSection("__TEXT", "__cstring", MCSectionMachO::S_CSTRING_LITERALS, SectionKind::getMergeable1ByteCString()); UStringSection = getContext().getMachOSection("__TEXT","__ustring", 0, SectionKind::getMergeable2ByteCString()); FourByteConstantSection // .literal4 = getContext().getMachOSection("__TEXT", "__literal4", MCSectionMachO::S_4BYTE_LITERALS, SectionKind::getMergeableConst4()); EightByteConstantSection // .literal8 = getContext().getMachOSection("__TEXT", "__literal8", MCSectionMachO::S_8BYTE_LITERALS, SectionKind::getMergeableConst8()); // ld_classic doesn't support .literal16 in 32-bit mode, and ld64 falls back // to using it in -static mode. SixteenByteConstantSection = 0; if (TM.getRelocationModel() != Reloc::Static && TM.getTargetData()->getPointerSize() == 32) SixteenByteConstantSection = // .literal16 getContext().getMachOSection("__TEXT", "__literal16", MCSectionMachO::S_16BYTE_LITERALS, SectionKind::getMergeableConst16()); ReadOnlySection // .const = getContext().getMachOSection("__TEXT", "__const", 0, SectionKind::getReadOnly()); TextCoalSection = getContext().getMachOSection("__TEXT", "__textcoal_nt", MCSectionMachO::S_COALESCED | MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS, SectionKind::getText()); ConstTextCoalSection = getContext().getMachOSection("__TEXT", "__const_coal", MCSectionMachO::S_COALESCED, SectionKind::getReadOnly()); ConstDataSection // .const_data = getContext().getMachOSection("__DATA", "__const", 0, SectionKind::getReadOnlyWithRel()); DataCoalSection = getContext().getMachOSection("__DATA","__datacoal_nt", MCSectionMachO::S_COALESCED, SectionKind::getDataRel()); DataCommonSection = getContext().getMachOSection("__DATA","__common", MCSectionMachO::S_ZEROFILL, SectionKind::getBSS()); DataBSSSection = getContext().getMachOSection("__DATA","__bss", MCSectionMachO::S_ZEROFILL, SectionKind::getBSS()); LazySymbolPointerSection = getContext().getMachOSection("__DATA", "__la_symbol_ptr", MCSectionMachO::S_LAZY_SYMBOL_POINTERS, SectionKind::getMetadata()); NonLazySymbolPointerSection = getContext().getMachOSection("__DATA", "__nl_symbol_ptr", MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS, SectionKind::getMetadata()); if (TM.getRelocationModel() == Reloc::Static) { StaticCtorSection = getContext().getMachOSection("__TEXT", "__constructor", 0, SectionKind::getDataRel()); StaticDtorSection = getContext().getMachOSection("__TEXT", "__destructor", 0, SectionKind::getDataRel()); } else { StaticCtorSection = getContext().getMachOSection("__DATA", "__mod_init_func", MCSectionMachO::S_MOD_INIT_FUNC_POINTERS, SectionKind::getDataRel()); StaticDtorSection = getContext().getMachOSection("__DATA", "__mod_term_func", MCSectionMachO::S_MOD_TERM_FUNC_POINTERS, SectionKind::getDataRel()); } // Exception Handling. LSDASection = getContext().getMachOSection("__TEXT", "__gcc_except_tab", 0, SectionKind::getReadOnlyWithRel()); EHFrameSection = getContext().getMachOSection("__TEXT", "__eh_frame", MCSectionMachO::S_COALESCED | MCSectionMachO::S_ATTR_NO_TOC | MCSectionMachO::S_ATTR_STRIP_STATIC_SYMS | MCSectionMachO::S_ATTR_LIVE_SUPPORT, SectionKind::getReadOnly()); // Debug Information. DwarfAbbrevSection = getContext().getMachOSection("__DWARF", "__debug_abbrev", MCSectionMachO::S_ATTR_DEBUG, SectionKind::getMetadata()); DwarfInfoSection = getContext().getMachOSection("__DWARF", "__debug_info", MCSectionMachO::S_ATTR_DEBUG, SectionKind::getMetadata()); DwarfLineSection = getContext().getMachOSection("__DWARF", "__debug_line", MCSectionMachO::S_ATTR_DEBUG, SectionKind::getMetadata()); DwarfFrameSection = getContext().getMachOSection("__DWARF", "__debug_frame", MCSectionMachO::S_ATTR_DEBUG, SectionKind::getMetadata()); DwarfPubNamesSection = getContext().getMachOSection("__DWARF", "__debug_pubnames", MCSectionMachO::S_ATTR_DEBUG, SectionKind::getMetadata()); DwarfPubTypesSection = getContext().getMachOSection("__DWARF", "__debug_pubtypes", MCSectionMachO::S_ATTR_DEBUG, SectionKind::getMetadata()); DwarfStrSection = getContext().getMachOSection("__DWARF", "__debug_str", MCSectionMachO::S_ATTR_DEBUG, SectionKind::getMetadata()); DwarfLocSection = getContext().getMachOSection("__DWARF", "__debug_loc", MCSectionMachO::S_ATTR_DEBUG, SectionKind::getMetadata()); DwarfARangesSection = getContext().getMachOSection("__DWARF", "__debug_aranges", MCSectionMachO::S_ATTR_DEBUG, SectionKind::getMetadata()); DwarfRangesSection = getContext().getMachOSection("__DWARF", "__debug_ranges", MCSectionMachO::S_ATTR_DEBUG, SectionKind::getMetadata()); DwarfMacroInfoSection = getContext().getMachOSection("__DWARF", "__debug_macinfo", MCSectionMachO::S_ATTR_DEBUG, SectionKind::getMetadata()); DwarfDebugInlineSection = getContext().getMachOSection("__DWARF", "__debug_inlined", MCSectionMachO::S_ATTR_DEBUG, SectionKind::getMetadata()); TLSExtraDataSection = TLSTLVSection; } 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, StubSize; std::string ErrorCode = MCSectionMachO::ParseSectionSpecifier(GV->getSection(), Segment, Section, TAA, StubSize); if (!ErrorCode.empty()) { // If invalid, report the error with report_fatal_error. report_fatal_error("Global variable '" + GV->getNameStr() + "' has an invalid section specifier '" + GV->getSection()+ "': " + ErrorCode + "."); // Fall back to dropping it into the data section. return DataSection; } // Get the section. const MCSectionMachO *S = getContext().getMachOSection(Segment, Section, TAA, StubSize, Kind); // 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->getNameStr() + "' 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(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(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(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(); 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 TargetLoweringObjectFile:: getExprForDwarfReference(SSym, Mang, MMI, Encoding & ~dwarf::DW_EH_PE_indirect, Streamer); } return TargetLoweringObjectFile:: getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer); } unsigned TargetLoweringObjectFileMachO::getPersonalityEncoding() const { return DW_EH_PE_indirect | DW_EH_PE_pcrel | DW_EH_PE_sdata4; } unsigned TargetLoweringObjectFileMachO::getLSDAEncoding() const { return DW_EH_PE_pcrel; } unsigned TargetLoweringObjectFileMachO::getFDEEncoding() const { return DW_EH_PE_pcrel; } unsigned TargetLoweringObjectFileMachO::getTTypeEncoding() const { return DW_EH_PE_indirect | DW_EH_PE_pcrel | DW_EH_PE_sdata4; } //===----------------------------------------------------------------------===// // COFF //===----------------------------------------------------------------------===// void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx, const TargetMachine &TM) { TargetLoweringObjectFile::Initialize(Ctx, TM); TextSection = getContext().getCOFFSection(".text", COFF::IMAGE_SCN_CNT_CODE | COFF::IMAGE_SCN_MEM_EXECUTE | COFF::IMAGE_SCN_MEM_READ, SectionKind::getText()); DataSection = getContext().getCOFFSection(".data", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE, SectionKind::getDataRel()); ReadOnlySection = getContext().getCOFFSection(".rdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ, SectionKind::getReadOnly()); StaticCtorSection = getContext().getCOFFSection(".ctors", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE, SectionKind::getDataRel()); StaticDtorSection = getContext().getCOFFSection(".dtors", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE, SectionKind::getDataRel()); // FIXME: We're emitting LSDA info into a readonly section on COFF, even // though it contains relocatable pointers. In PIC mode, this is probably a // big runtime hit for C++ apps. Either the contents of the LSDA need to be // adjusted or this should be a data section. LSDASection = getContext().getCOFFSection(".gcc_except_table", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ, SectionKind::getReadOnly()); EHFrameSection = getContext().getCOFFSection(".eh_frame", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE, SectionKind::getDataRel()); // Debug info. DwarfAbbrevSection = getContext().getCOFFSection(".debug_abbrev", COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_MEM_READ, SectionKind::getMetadata()); DwarfInfoSection = getContext().getCOFFSection(".debug_info", COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_MEM_READ, SectionKind::getMetadata()); DwarfLineSection = getContext().getCOFFSection(".debug_line", COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_MEM_READ, SectionKind::getMetadata()); DwarfFrameSection = getContext().getCOFFSection(".debug_frame", COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_MEM_READ, SectionKind::getMetadata()); DwarfPubNamesSection = getContext().getCOFFSection(".debug_pubnames", COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_MEM_READ, SectionKind::getMetadata()); DwarfPubTypesSection = getContext().getCOFFSection(".debug_pubtypes", COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_MEM_READ, SectionKind::getMetadata()); DwarfStrSection = getContext().getCOFFSection(".debug_str", COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_MEM_READ, SectionKind::getMetadata()); DwarfLocSection = getContext().getCOFFSection(".debug_loc", COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_MEM_READ, SectionKind::getMetadata()); DwarfARangesSection = getContext().getCOFFSection(".debug_aranges", COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_MEM_READ, SectionKind::getMetadata()); DwarfRangesSection = getContext().getCOFFSection(".debug_ranges", COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_MEM_READ, SectionKind::getMetadata()); DwarfMacroInfoSection = getContext().getCOFFSection(".debug_macinfo", COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_MEM_READ, SectionKind::getMetadata()); DrectveSection = getContext().getCOFFSection(".drectve", COFF::IMAGE_SCN_LNK_INFO, SectionKind::getMetadata()); } 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_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.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$linkonce"; if (Kind.isBSS ()) return ".bss$linkonce"; if (Kind.isWriteable()) return ".data$linkonce"; return ".rdata$linkonce"; } const MCSection *TargetLoweringObjectFileCOFF:: SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind, Mangler *Mang, const TargetMachine &TM) const { assert(!Kind.isThreadLocal() && "Doesn't support TLS"); // 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(), Sym->getName().end()); unsigned Characteristics = getCOFFSectionFlags(Kind); Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT; return getContext().getCOFFSection(Name.str(), Characteristics, COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH, Kind); } if (Kind.isText()) return getTextSection(); return getDataSection(); }