| //===-- llvm/Target/TargetLoweringObjectFile.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/Target/TargetLoweringObjectFile.h" |
| #include "llvm/Constants.h" |
| #include "llvm/DerivedTypes.h" |
| #include "llvm/Function.h" |
| #include "llvm/GlobalVariable.h" |
| #include "llvm/MC/MCContext.h" |
| #include "llvm/MC/MCSectionMachO.h" |
| #include "llvm/MC/MCSectionELF.h" |
| #include "llvm/Target/TargetData.h" |
| #include "llvm/Target/TargetMachine.h" |
| #include "llvm/Target/TargetOptions.h" |
| #include "llvm/Support/Mangler.h" |
| #include "llvm/ADT/SmallString.h" |
| #include "llvm/ADT/StringExtras.h" |
| using namespace llvm; |
| |
| //===----------------------------------------------------------------------===// |
| // Generic Code |
| //===----------------------------------------------------------------------===// |
| |
| TargetLoweringObjectFile::TargetLoweringObjectFile() : Ctx(0) { |
| TextSection = 0; |
| DataSection = 0; |
| BSSSection = 0; |
| ReadOnlySection = 0; |
| StaticCtorSection = 0; |
| StaticDtorSection = 0; |
| LSDASection = 0; |
| EHFrameSection = 0; |
| |
| DwarfAbbrevSection = 0; |
| DwarfInfoSection = 0; |
| DwarfLineSection = 0; |
| DwarfFrameSection = 0; |
| DwarfPubNamesSection = 0; |
| DwarfPubTypesSection = 0; |
| DwarfDebugInlineSection = 0; |
| DwarfStrSection = 0; |
| DwarfLocSection = 0; |
| DwarfARangesSection = 0; |
| DwarfRangesSection = 0; |
| DwarfMacroInfoSection = 0; |
| } |
| |
| TargetLoweringObjectFile::~TargetLoweringObjectFile() { |
| } |
| |
| static bool isSuitableForBSS(const GlobalVariable *GV) { |
| Constant *C = GV->getInitializer(); |
| |
| // Must have zero initializer. |
| if (!C->isNullValue()) |
| return false; |
| |
| // Leave constant zeros in readonly constant sections, so they can be shared. |
| if (GV->isConstant()) |
| return false; |
| |
| // If the global has an explicit section specified, don't put it in BSS. |
| if (!GV->getSection().empty()) |
| return false; |
| |
| // If -nozero-initialized-in-bss is specified, don't ever use BSS. |
| if (NoZerosInBSS) |
| return false; |
| |
| // Otherwise, put it in BSS! |
| return true; |
| } |
| |
| /// IsNullTerminatedString - Return true if the specified constant (which is |
| /// known to have a type that is an array of 1/2/4 byte elements) ends with a |
| /// nul value and contains no other nuls in it. |
| static bool IsNullTerminatedString(const Constant *C) { |
| const ArrayType *ATy = cast<ArrayType>(C->getType()); |
| |
| // First check: is we have constant array of i8 terminated with zero |
| if (const ConstantArray *CVA = dyn_cast<ConstantArray>(C)) { |
| if (ATy->getNumElements() == 0) return false; |
| |
| ConstantInt *Null = |
| dyn_cast<ConstantInt>(CVA->getOperand(ATy->getNumElements()-1)); |
| if (Null == 0 || Null->getZExtValue() != 0) |
| return false; // Not null terminated. |
| |
| // Verify that the null doesn't occur anywhere else in the string. |
| for (unsigned i = 0, e = ATy->getNumElements()-1; i != e; ++i) |
| // Reject constantexpr elements etc. |
| if (!isa<ConstantInt>(CVA->getOperand(i)) || |
| CVA->getOperand(i) == Null) |
| return false; |
| return true; |
| } |
| |
| // Another possibility: [1 x i8] zeroinitializer |
| if (isa<ConstantAggregateZero>(C)) |
| return ATy->getNumElements() == 1; |
| |
| return false; |
| } |
| |
| /// getKindForGlobal - This is a top-level target-independent classifier for |
| /// a global variable. Given an global variable and information from TM, it |
| /// classifies the global in a variety of ways that make various target |
| /// implementations simpler. The target implementation is free to ignore this |
| /// extra info of course. |
| SectionKind TargetLoweringObjectFile::getKindForGlobal(const GlobalValue *GV, |
| const TargetMachine &TM){ |
| assert(!GV->isDeclaration() && !GV->hasAvailableExternallyLinkage() && |
| "Can only be used for global definitions"); |
| |
| Reloc::Model ReloModel = TM.getRelocationModel(); |
| |
| // Early exit - functions should be always in text sections. |
| const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV); |
| if (GVar == 0) |
| return SectionKind::getText(); |
| |
| // Handle thread-local data first. |
| if (GVar->isThreadLocal()) { |
| if (isSuitableForBSS(GVar)) |
| return SectionKind::getThreadBSS(); |
| return SectionKind::getThreadData(); |
| } |
| |
| // Variable can be easily put to BSS section. |
| if (isSuitableForBSS(GVar)) |
| return SectionKind::getBSS(); |
| |
| Constant *C = GVar->getInitializer(); |
| |
| // If the global is marked constant, we can put it into a mergable section, |
| // a mergable string section, or general .data if it contains relocations. |
| if (GVar->isConstant()) { |
| // If the initializer for the global contains something that requires a |
| // relocation, then we may have to drop this into a wriable data section |
| // even though it is marked const. |
| switch (C->getRelocationInfo()) { |
| default: llvm_unreachable("unknown relocation info kind"); |
| case Constant::NoRelocation: |
| // If initializer is a null-terminated string, put it in a "cstring" |
| // section of the right width. |
| if (const ArrayType *ATy = dyn_cast<ArrayType>(C->getType())) { |
| if (const IntegerType *ITy = |
| dyn_cast<IntegerType>(ATy->getElementType())) { |
| if ((ITy->getBitWidth() == 8 || ITy->getBitWidth() == 16 || |
| ITy->getBitWidth() == 32) && |
| IsNullTerminatedString(C)) { |
| if (ITy->getBitWidth() == 8) |
| return SectionKind::getMergeable1ByteCString(); |
| if (ITy->getBitWidth() == 16) |
| return SectionKind::getMergeable2ByteCString(); |
| |
| assert(ITy->getBitWidth() == 32 && "Unknown width"); |
| return SectionKind::getMergeable4ByteCString(); |
| } |
| } |
| } |
| |
| // Otherwise, just drop it into a mergable constant section. If we have |
| // a section for this size, use it, otherwise use the arbitrary sized |
| // mergable section. |
| switch (TM.getTargetData()->getTypeAllocSize(C->getType())) { |
| case 4: return SectionKind::getMergeableConst4(); |
| case 8: return SectionKind::getMergeableConst8(); |
| case 16: return SectionKind::getMergeableConst16(); |
| default: return SectionKind::getMergeableConst(); |
| } |
| |
| case Constant::LocalRelocation: |
| // In static relocation model, the linker will resolve all addresses, so |
| // the relocation entries will actually be constants by the time the app |
| // starts up. However, we can't put this into a mergable section, because |
| // the linker doesn't take relocations into consideration when it tries to |
| // merge entries in the section. |
| if (ReloModel == Reloc::Static) |
| return SectionKind::getReadOnly(); |
| |
| // Otherwise, the dynamic linker needs to fix it up, put it in the |
| // writable data.rel.local section. |
| return SectionKind::getReadOnlyWithRelLocal(); |
| |
| case Constant::GlobalRelocations: |
| // In static relocation model, the linker will resolve all addresses, so |
| // the relocation entries will actually be constants by the time the app |
| // starts up. However, we can't put this into a mergable section, because |
| // the linker doesn't take relocations into consideration when it tries to |
| // merge entries in the section. |
| if (ReloModel == Reloc::Static) |
| return SectionKind::getReadOnly(); |
| |
| // Otherwise, the dynamic linker needs to fix it up, put it in the |
| // writable data.rel section. |
| return SectionKind::getReadOnlyWithRel(); |
| } |
| } |
| |
| // Okay, this isn't a constant. If the initializer for the global is going |
| // to require a runtime relocation by the dynamic linker, put it into a more |
| // specific section to improve startup time of the app. This coalesces these |
| // globals together onto fewer pages, improving the locality of the dynamic |
| // linker. |
| if (ReloModel == Reloc::Static) |
| return SectionKind::getDataNoRel(); |
| |
| switch (C->getRelocationInfo()) { |
| default: llvm_unreachable("unknown relocation info kind"); |
| case Constant::NoRelocation: |
| return SectionKind::getDataNoRel(); |
| case Constant::LocalRelocation: |
| return SectionKind::getDataRelLocal(); |
| case Constant::GlobalRelocations: |
| return SectionKind::getDataRel(); |
| } |
| } |
| |
| /// SectionForGlobal - This method computes the appropriate section to emit |
| /// the specified global variable or function definition. This should not |
| /// be passed external (or available externally) globals. |
| const MCSection *TargetLoweringObjectFile:: |
| SectionForGlobal(const GlobalValue *GV, SectionKind Kind, Mangler *Mang, |
| const TargetMachine &TM) const { |
| // Select section name. |
| if (GV->hasSection()) |
| return getExplicitSectionGlobal(GV, Kind, Mang, TM); |
| |
| |
| // Use default section depending on the 'type' of global |
| return SelectSectionForGlobal(GV, Kind, Mang, TM); |
| } |
| |
| |
| // Lame default implementation. Calculate the section name for global. |
| const MCSection * |
| TargetLoweringObjectFile::SelectSectionForGlobal(const GlobalValue *GV, |
| SectionKind Kind, |
| Mangler *Mang, |
| const TargetMachine &TM) const{ |
| assert(!Kind.isThreadLocal() && "Doesn't support TLS"); |
| |
| if (Kind.isText()) |
| return getTextSection(); |
| |
| if (Kind.isBSS() && BSSSection != 0) |
| return BSSSection; |
| |
| if (Kind.isReadOnly() && ReadOnlySection != 0) |
| return ReadOnlySection; |
| |
| return getDataSection(); |
| } |
| |
| /// getSectionForConstant - Given a mergable constant with the |
| /// specified size and relocation information, return a section that it |
| /// should be placed in. |
| const MCSection * |
| TargetLoweringObjectFile::getSectionForConstant(SectionKind Kind) const { |
| if (Kind.isReadOnly() && ReadOnlySection != 0) |
| return ReadOnlySection; |
| |
| return DataSection; |
| } |
| |
| |
| |
| //===----------------------------------------------------------------------===// |
| // ELF |
| //===----------------------------------------------------------------------===// |
| typedef StringMap<const MCSectionELF*> ELFUniqueMapTy; |
| |
| TargetLoweringObjectFileELF::~TargetLoweringObjectFileELF() { |
| // If we have the section uniquing map, free it. |
| delete (ELFUniqueMapTy*)UniquingMap; |
| } |
| |
| const MCSection *TargetLoweringObjectFileELF:: |
| getELFSection(StringRef Section, unsigned Type, unsigned Flags, |
| SectionKind Kind, bool IsExplicit) const { |
| if (UniquingMap == 0) |
| UniquingMap = new ELFUniqueMapTy(); |
| ELFUniqueMapTy &Map = *(ELFUniqueMapTy*)UniquingMap; |
| |
| // Do the lookup, if we have a hit, return it. |
| const MCSectionELF *&Entry = Map[Section]; |
| if (Entry) return Entry; |
| |
| return Entry = MCSectionELF::Create(Section, Type, Flags, Kind, IsExplicit, |
| getContext()); |
| } |
| |
| void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx, |
| const TargetMachine &TM) { |
| if (UniquingMap != 0) |
| ((ELFUniqueMapTy*)UniquingMap)->clear(); |
| TargetLoweringObjectFile::Initialize(Ctx, TM); |
| |
| BSSSection = |
| getELFSection(".bss", MCSectionELF::SHT_NOBITS, |
| MCSectionELF::SHF_WRITE | MCSectionELF::SHF_ALLOC, |
| SectionKind::getBSS()); |
| |
| TextSection = |
| getELFSection(".text", MCSectionELF::SHT_PROGBITS, |
| MCSectionELF::SHF_EXECINSTR | MCSectionELF::SHF_ALLOC, |
| SectionKind::getText()); |
| |
| DataSection = |
| getELFSection(".data", MCSectionELF::SHT_PROGBITS, |
| MCSectionELF::SHF_WRITE | MCSectionELF::SHF_ALLOC, |
| SectionKind::getDataRel()); |
| |
| ReadOnlySection = |
| getELFSection(".rodata", MCSectionELF::SHT_PROGBITS, |
| MCSectionELF::SHF_ALLOC, |
| SectionKind::getReadOnly()); |
| |
| TLSDataSection = |
| getELFSection(".tdata", MCSectionELF::SHT_PROGBITS, |
| MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_TLS | |
| MCSectionELF::SHF_WRITE, SectionKind::getThreadData()); |
| |
| TLSBSSSection = |
| getELFSection(".tbss", MCSectionELF::SHT_NOBITS, |
| MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_TLS | |
| MCSectionELF::SHF_WRITE, SectionKind::getThreadBSS()); |
| |
| DataRelSection = |
| getELFSection(".data.rel", MCSectionELF::SHT_PROGBITS, |
| MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE, |
| SectionKind::getDataRel()); |
| |
| DataRelLocalSection = |
| getELFSection(".data.rel.local", MCSectionELF::SHT_PROGBITS, |
| MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE, |
| SectionKind::getDataRelLocal()); |
| |
| DataRelROSection = |
| getELFSection(".data.rel.ro", MCSectionELF::SHT_PROGBITS, |
| MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE, |
| SectionKind::getReadOnlyWithRel()); |
| |
| DataRelROLocalSection = |
| getELFSection(".data.rel.ro.local", MCSectionELF::SHT_PROGBITS, |
| MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE, |
| SectionKind::getReadOnlyWithRelLocal()); |
| |
| MergeableConst4Section = |
| getELFSection(".rodata.cst4", MCSectionELF::SHT_PROGBITS, |
| MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_MERGE, |
| SectionKind::getMergeableConst4()); |
| |
| MergeableConst8Section = |
| getELFSection(".rodata.cst8", MCSectionELF::SHT_PROGBITS, |
| MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_MERGE, |
| SectionKind::getMergeableConst8()); |
| |
| MergeableConst16Section = |
| getELFSection(".rodata.cst16", MCSectionELF::SHT_PROGBITS, |
| MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_MERGE, |
| SectionKind::getMergeableConst16()); |
| |
| StaticCtorSection = |
| getELFSection(".ctors", MCSectionELF::SHT_PROGBITS, |
| MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE, |
| SectionKind::getDataRel()); |
| |
| StaticDtorSection = |
| 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 = |
| getELFSection(".gcc_except_table", MCSectionELF::SHT_PROGBITS, |
| MCSectionELF::SHF_ALLOC, SectionKind::getReadOnly()); |
| EHFrameSection = |
| getELFSection(".eh_frame", MCSectionELF::SHT_PROGBITS, |
| MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE, |
| SectionKind::getDataRel()); |
| |
| // Debug Info Sections. |
| DwarfAbbrevSection = |
| getELFSection(".debug_abbrev", MCSectionELF::SHT_PROGBITS, 0, |
| SectionKind::getMetadata()); |
| DwarfInfoSection = |
| getELFSection(".debug_info", MCSectionELF::SHT_PROGBITS, 0, |
| SectionKind::getMetadata()); |
| DwarfLineSection = |
| getELFSection(".debug_line", MCSectionELF::SHT_PROGBITS, 0, |
| SectionKind::getMetadata()); |
| DwarfFrameSection = |
| getELFSection(".debug_frame", MCSectionELF::SHT_PROGBITS, 0, |
| SectionKind::getMetadata()); |
| DwarfPubNamesSection = |
| getELFSection(".debug_pubnames", MCSectionELF::SHT_PROGBITS, 0, |
| SectionKind::getMetadata()); |
| DwarfPubTypesSection = |
| getELFSection(".debug_pubtypes", MCSectionELF::SHT_PROGBITS, 0, |
| SectionKind::getMetadata()); |
| DwarfStrSection = |
| getELFSection(".debug_str", MCSectionELF::SHT_PROGBITS, 0, |
| SectionKind::getMetadata()); |
| DwarfLocSection = |
| getELFSection(".debug_loc", MCSectionELF::SHT_PROGBITS, 0, |
| SectionKind::getMetadata()); |
| DwarfARangesSection = |
| getELFSection(".debug_aranges", MCSectionELF::SHT_PROGBITS, 0, |
| SectionKind::getMetadata()); |
| DwarfRangesSection = |
| getELFSection(".debug_ranges", MCSectionELF::SHT_PROGBITS, 0, |
| SectionKind::getMetadata()); |
| DwarfMacroInfoSection = |
| getELFSection(".debug_macinfo", MCSectionELF::SHT_PROGBITS, 0, |
| SectionKind::getMetadata()); |
| } |
| |
| |
| static SectionKind |
| getELFKindForNamedSection(const char *Name, SectionKind K) { |
| if (Name[0] != '.') return K; |
| |
| // Some lame default implementation based on some magic section names. |
| if (strncmp(Name, ".gnu.linkonce.b.", 16) == 0 || |
| strncmp(Name, ".llvm.linkonce.b.", 17) == 0 || |
| strncmp(Name, ".gnu.linkonce.sb.", 17) == 0 || |
| strncmp(Name, ".llvm.linkonce.sb.", 18) == 0) |
| return SectionKind::getBSS(); |
| |
| if (strcmp(Name, ".tdata") == 0 || |
| strncmp(Name, ".tdata.", 7) == 0 || |
| strncmp(Name, ".gnu.linkonce.td.", 17) == 0 || |
| strncmp(Name, ".llvm.linkonce.td.", 18) == 0) |
| return SectionKind::getThreadData(); |
| |
| if (strcmp(Name, ".tbss") == 0 || |
| strncmp(Name, ".tbss.", 6) == 0 || |
| strncmp(Name, ".gnu.linkonce.tb.", 17) == 0 || |
| strncmp(Name, ".llvm.linkonce.tb.", 18) == 0) |
| return SectionKind::getThreadBSS(); |
| |
| return K; |
| } |
| |
| |
| static unsigned |
| getELFSectionType(const char *Name, SectionKind K) { |
| |
| if (strcmp(Name, ".init_array") == 0) |
| return MCSectionELF::SHT_INIT_ARRAY; |
| |
| if (strcmp(Name, ".fini_array") == 0) |
| return MCSectionELF::SHT_FINI_ARRAY; |
| |
| if (strcmp(Name, ".preinit_array") == 0) |
| 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 { |
| const char *SectionName = GV->getSection().c_str(); |
| |
| // Infer section flags from the section name if we can. |
| Kind = getELFKindForNamedSection(SectionName, Kind); |
| |
| return 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.isBSS()) return ".gnu.linkonce.b."; |
| 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."; |
| } |
| |
| const MCSection *TargetLoweringObjectFileELF:: |
| 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 = getSectionPrefixForUniqueGlobal(Kind); |
| std::string Name = Mang->makeNameProper(GV->getNameStr()); |
| |
| return getELFSection((Prefix+Name).c_str(), |
| getELFSectionType((Prefix+Name).c_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<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 getELFSection(Name.c_str(), 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; |
| |
| if (Kind.isBSS()) 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; |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // MachO |
| //===----------------------------------------------------------------------===// |
| |
| typedef StringMap<const MCSectionMachO*> MachOUniqueMapTy; |
| |
| TargetLoweringObjectFileMachO::~TargetLoweringObjectFileMachO() { |
| // If we have the MachO uniquing map, free it. |
| delete (MachOUniqueMapTy*)UniquingMap; |
| } |
| |
| |
| const MCSectionMachO *TargetLoweringObjectFileMachO:: |
| getMachOSection(const StringRef &Segment, const StringRef &Section, |
| unsigned TypeAndAttributes, |
| unsigned Reserved2, SectionKind Kind) const { |
| // We unique sections by their segment/section pair. The returned section |
| // may not have the same flags as the requested section, if so this should be |
| // diagnosed by the client as an error. |
| |
| // Create the map if it doesn't already exist. |
| if (UniquingMap == 0) |
| UniquingMap = new MachOUniqueMapTy(); |
| MachOUniqueMapTy &Map = *(MachOUniqueMapTy*)UniquingMap; |
| |
| // Form the name to look up. |
| SmallString<64> Name; |
| Name.append(Segment.begin(), Segment.end()); |
| Name.push_back(','); |
| Name.append(Section.begin(), Section.end()); |
| |
| // Do the lookup, if we have a hit, return it. |
| const MCSectionMachO *&Entry = Map[StringRef(Name.data(), Name.size())]; |
| if (Entry) return Entry; |
| |
| // Otherwise, return a new section. |
| return Entry = MCSectionMachO::Create(Segment, Section, TypeAndAttributes, |
| Reserved2, Kind, getContext()); |
| } |
| |
| |
| void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx, |
| const TargetMachine &TM) { |
| if (UniquingMap != 0) |
| ((MachOUniqueMapTy*)UniquingMap)->clear(); |
| TargetLoweringObjectFile::Initialize(Ctx, TM); |
| |
| TextSection // .text |
| = getMachOSection("__TEXT", "__text", |
| MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS, |
| SectionKind::getText()); |
| DataSection // .data |
| = getMachOSection("__DATA", "__data", 0, SectionKind::getDataRel()); |
| |
| CStringSection // .cstring |
| = getMachOSection("__TEXT", "__cstring", MCSectionMachO::S_CSTRING_LITERALS, |
| SectionKind::getMergeable1ByteCString()); |
| UStringSection |
| = getMachOSection("__TEXT","__ustring", 0, |
| SectionKind::getMergeable2ByteCString()); |
| FourByteConstantSection // .literal4 |
| = getMachOSection("__TEXT", "__literal4", MCSectionMachO::S_4BYTE_LITERALS, |
| SectionKind::getMergeableConst4()); |
| EightByteConstantSection // .literal8 |
| = 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 |
| getMachOSection("__TEXT", "__literal16",MCSectionMachO::S_16BYTE_LITERALS, |
| SectionKind::getMergeableConst16()); |
| |
| ReadOnlySection // .const |
| = getMachOSection("__TEXT", "__const", 0, SectionKind::getReadOnly()); |
| |
| TextCoalSection |
| = getMachOSection("__TEXT", "__textcoal_nt", |
| MCSectionMachO::S_COALESCED | |
| MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS, |
| SectionKind::getText()); |
| ConstTextCoalSection |
| = getMachOSection("__TEXT", "__const_coal", MCSectionMachO::S_COALESCED, |
| SectionKind::getText()); |
| ConstDataCoalSection |
| = getMachOSection("__DATA","__const_coal", MCSectionMachO::S_COALESCED, |
| SectionKind::getText()); |
| ConstDataSection // .const_data |
| = getMachOSection("__DATA", "__const", 0, |
| SectionKind::getReadOnlyWithRel()); |
| DataCoalSection |
| = getMachOSection("__DATA","__datacoal_nt", MCSectionMachO::S_COALESCED, |
| SectionKind::getDataRel()); |
| |
| |
| LazySymbolPointerSection |
| = getMachOSection("__DATA", "__la_symbol_ptr", |
| MCSectionMachO::S_LAZY_SYMBOL_POINTERS, |
| SectionKind::getMetadata()); |
| NonLazySymbolPointerSection |
| = getMachOSection("__DATA", "__nl_symbol_ptr", |
| MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS, |
| SectionKind::getMetadata()); |
| |
| if (TM.getRelocationModel() == Reloc::Static) { |
| StaticCtorSection |
| = getMachOSection("__TEXT", "__constructor", 0,SectionKind::getDataRel()); |
| StaticDtorSection |
| = getMachOSection("__TEXT", "__destructor", 0, SectionKind::getDataRel()); |
| } else { |
| StaticCtorSection |
| = getMachOSection("__DATA", "__mod_init_func", |
| MCSectionMachO::S_MOD_INIT_FUNC_POINTERS, |
| SectionKind::getDataRel()); |
| StaticDtorSection |
| = getMachOSection("__DATA", "__mod_term_func", |
| MCSectionMachO::S_MOD_TERM_FUNC_POINTERS, |
| SectionKind::getDataRel()); |
| } |
| |
| // Exception Handling. |
| LSDASection = getMachOSection("__DATA", "__gcc_except_tab", 0, |
| SectionKind::getDataRel()); |
| EHFrameSection = |
| 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 = |
| getMachOSection("__DWARF", "__debug_abbrev", MCSectionMachO::S_ATTR_DEBUG, |
| SectionKind::getMetadata()); |
| DwarfInfoSection = |
| getMachOSection("__DWARF", "__debug_info", MCSectionMachO::S_ATTR_DEBUG, |
| SectionKind::getMetadata()); |
| DwarfLineSection = |
| getMachOSection("__DWARF", "__debug_line", MCSectionMachO::S_ATTR_DEBUG, |
| SectionKind::getMetadata()); |
| DwarfFrameSection = |
| getMachOSection("__DWARF", "__debug_frame", MCSectionMachO::S_ATTR_DEBUG, |
| SectionKind::getMetadata()); |
| DwarfPubNamesSection = |
| getMachOSection("__DWARF", "__debug_pubnames", MCSectionMachO::S_ATTR_DEBUG, |
| SectionKind::getMetadata()); |
| DwarfPubTypesSection = |
| getMachOSection("__DWARF", "__debug_pubtypes", MCSectionMachO::S_ATTR_DEBUG, |
| SectionKind::getMetadata()); |
| DwarfStrSection = |
| getMachOSection("__DWARF", "__debug_str", MCSectionMachO::S_ATTR_DEBUG, |
| SectionKind::getMetadata()); |
| DwarfLocSection = |
| getMachOSection("__DWARF", "__debug_loc", MCSectionMachO::S_ATTR_DEBUG, |
| SectionKind::getMetadata()); |
| DwarfARangesSection = |
| getMachOSection("__DWARF", "__debug_aranges", MCSectionMachO::S_ATTR_DEBUG, |
| SectionKind::getMetadata()); |
| DwarfRangesSection = |
| getMachOSection("__DWARF", "__debug_ranges", MCSectionMachO::S_ATTR_DEBUG, |
| SectionKind::getMetadata()); |
| DwarfMacroInfoSection = |
| getMachOSection("__DWARF", "__debug_macinfo", MCSectionMachO::S_ATTR_DEBUG, |
| SectionKind::getMetadata()); |
| DwarfDebugInlineSection = |
| getMachOSection("__DWARF", "__debug_inlined", MCSectionMachO::S_ATTR_DEBUG, |
| SectionKind::getMetadata()); |
| } |
| |
| 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 llvm_report_error. |
| llvm_report_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 = |
| 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 llvm_report_error. |
| llvm_report_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 { |
| assert(!Kind.isThreadLocal() && "Darwin doesn't support TLS"); |
| |
| 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() || |
| Kind.isMergeable2ByteCString()) { |
| if (TM.getTargetData()->getPreferredAlignment( |
| cast<GlobalVariable>(GV)) < 32) { |
| if (Kind.isMergeable1ByteCString()) |
| return CStringSection; |
| assert(Kind.isMergeable2ByteCString()); |
| 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; |
| |
| // 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()) |
| 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. |
| const std::string &Name = Mang->getMangledName(GV); |
| if (Name[0] == 'L' || Name[0] == 'l') |
| return false; |
| } |
| |
| return true; |
| } |
| |
| |
| //===----------------------------------------------------------------------===// |
| // COFF |
| //===----------------------------------------------------------------------===// |
| |
| typedef StringMap<const MCSectionCOFF*> COFFUniqueMapTy; |
| |
| TargetLoweringObjectFileCOFF::~TargetLoweringObjectFileCOFF() { |
| delete (COFFUniqueMapTy*)UniquingMap; |
| } |
| |
| |
| const MCSection *TargetLoweringObjectFileCOFF:: |
| getCOFFSection(const char *Name, bool isDirective, SectionKind Kind) const { |
| // Create the map if it doesn't already exist. |
| if (UniquingMap == 0) |
| UniquingMap = new MachOUniqueMapTy(); |
| COFFUniqueMapTy &Map = *(COFFUniqueMapTy*)UniquingMap; |
| |
| // Do the lookup, if we have a hit, return it. |
| const MCSectionCOFF *&Entry = Map[Name]; |
| if (Entry) return Entry; |
| |
| return Entry = MCSectionCOFF::Create(Name, isDirective, Kind, getContext()); |
| } |
| |
| void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx, |
| const TargetMachine &TM) { |
| if (UniquingMap != 0) |
| ((COFFUniqueMapTy*)UniquingMap)->clear(); |
| TargetLoweringObjectFile::Initialize(Ctx, TM); |
| TextSection = getCOFFSection("\t.text", true, SectionKind::getText()); |
| DataSection = getCOFFSection("\t.data", true, SectionKind::getDataRel()); |
| StaticCtorSection = |
| getCOFFSection(".ctors", false, SectionKind::getDataRel()); |
| StaticDtorSection = |
| getCOFFSection(".dtors", false, 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 = |
| getCOFFSection(".gcc_except_table", false, SectionKind::getReadOnly()); |
| EHFrameSection = |
| getCOFFSection(".eh_frame", false, SectionKind::getDataRel()); |
| |
| // Debug info. |
| // FIXME: Don't use 'directive' mode here. |
| DwarfAbbrevSection = |
| getCOFFSection("\t.section\t.debug_abbrev,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfInfoSection = |
| getCOFFSection("\t.section\t.debug_info,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfLineSection = |
| getCOFFSection("\t.section\t.debug_line,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfFrameSection = |
| getCOFFSection("\t.section\t.debug_frame,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfPubNamesSection = |
| getCOFFSection("\t.section\t.debug_pubnames,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfPubTypesSection = |
| getCOFFSection("\t.section\t.debug_pubtypes,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfStrSection = |
| getCOFFSection("\t.section\t.debug_str,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfLocSection = |
| getCOFFSection("\t.section\t.debug_loc,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfARangesSection = |
| getCOFFSection("\t.section\t.debug_aranges,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfRangesSection = |
| getCOFFSection("\t.section\t.debug_ranges,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfMacroInfoSection = |
| getCOFFSection("\t.section\t.debug_macinfo,\"dr\"", |
| true, SectionKind::getMetadata()); |
| } |
| |
| const MCSection *TargetLoweringObjectFileCOFF:: |
| getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind, |
| Mangler *Mang, const TargetMachine &TM) const { |
| return getCOFFSection(GV->getSection().c_str(), false, Kind); |
| } |
| |
| static const char *getCOFFSectionPrefixForUniqueGlobal(SectionKind Kind) { |
| if (Kind.isText()) |
| return ".text$linkonce"; |
| if (Kind.isWriteable()) |
| return ".data$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); |
| std::string Name = Mang->makeNameProper(GV->getNameStr()); |
| return getCOFFSection((Prefix+Name).c_str(), false, Kind); |
| } |
| |
| if (Kind.isText()) |
| return getTextSection(); |
| |
| return getDataSection(); |
| } |
| |