| //===-- 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/GlobalVariable.h" |
| #include "llvm/MC/MCContext.h" |
| #include "llvm/MC/MCSection.h" |
| #include "llvm/Target/TargetMachine.h" |
| #include "llvm/Target/TargetData.h" |
| #include "llvm/Target/TargetOptions.h" |
| #include "llvm/Support/Mangler.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; |
| } |
| |
| /// SectionKindForGlobal - 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. |
| static SectionKind SectionKindForGlobal(const GlobalValue *GV, |
| const TargetMachine &TM) { |
| 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, Mangler *Mang, |
| const TargetMachine &TM) const { |
| assert(!GV->isDeclaration() && !GV->hasAvailableExternallyLinkage() && |
| "Can only be used for global definitions"); |
| |
| SectionKind Kind = SectionKindForGlobal(GV, TM); |
| |
| // Select section name. |
| if (GV->hasSection()) { |
| // If the target has special section hacks for specifically named globals, |
| // return them now. |
| if (const MCSection *TS = getSpecialCasedSectionGlobals(GV, Mang, Kind)) |
| return TS; |
| |
| // If the target has magic semantics for certain section names, make sure to |
| // pick up the flags. This allows the user to write things with attribute |
| // section and still get the appropriate section flags printed. |
| Kind = getKindForNamedSection(GV->getSection().c_str(), Kind); |
| |
| return getOrCreateSection(GV->getSection().c_str(), false, Kind); |
| } |
| |
| |
| // 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; |
| } |
| |
| |
| const MCSection *TargetLoweringObjectFile:: |
| getOrCreateSection(const char *Name, bool isDirective, SectionKind Kind) const { |
| if (MCSection *S = Ctx->GetSection(Name)) |
| return S; |
| return MCSection::Create(Name, isDirective, Kind, *Ctx); |
| } |
| |
| |
| |
| //===----------------------------------------------------------------------===// |
| // ELF |
| //===----------------------------------------------------------------------===// |
| |
| void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx, |
| const TargetMachine &TM) { |
| TargetLoweringObjectFile::Initialize(Ctx, TM); |
| if (!HasCrazyBSS) |
| BSSSection = getOrCreateSection("\t.bss", true, SectionKind::getBSS()); |
| else |
| // PPC/Linux doesn't support the .bss directive, it needs .section .bss. |
| // FIXME: Does .section .bss work everywhere?? |
| // FIXME2: this should just be handle by the section printer. We should get |
| // away from syntactic view of the sections and MCSection should just be a |
| // semantic view. |
| BSSSection = getOrCreateSection("\t.bss", false, SectionKind::getBSS()); |
| |
| |
| TextSection = getOrCreateSection("\t.text", true, SectionKind::getText()); |
| DataSection = getOrCreateSection("\t.data", true, SectionKind::getDataRel()); |
| ReadOnlySection = |
| getOrCreateSection("\t.rodata", false, SectionKind::getReadOnly()); |
| TLSDataSection = |
| getOrCreateSection("\t.tdata", false, SectionKind::getThreadData()); |
| |
| TLSBSSSection = getOrCreateSection("\t.tbss", false, |
| SectionKind::getThreadBSS()); |
| |
| DataRelSection = getOrCreateSection("\t.data.rel", false, |
| SectionKind::getDataRel()); |
| DataRelLocalSection = getOrCreateSection("\t.data.rel.local", false, |
| SectionKind::getDataRelLocal()); |
| DataRelROSection = getOrCreateSection("\t.data.rel.ro", false, |
| SectionKind::getReadOnlyWithRel()); |
| DataRelROLocalSection = |
| getOrCreateSection("\t.data.rel.ro.local", false, |
| SectionKind::getReadOnlyWithRelLocal()); |
| |
| MergeableConst4Section = getOrCreateSection(".rodata.cst4", false, |
| SectionKind::getMergeableConst4()); |
| MergeableConst8Section = getOrCreateSection(".rodata.cst8", false, |
| SectionKind::getMergeableConst8()); |
| MergeableConst16Section = getOrCreateSection(".rodata.cst16", false, |
| SectionKind::getMergeableConst16()); |
| |
| StaticCtorSection = |
| getOrCreateSection(".ctors", false, SectionKind::getDataRel()); |
| StaticDtorSection = |
| getOrCreateSection(".dtors", false, 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 = |
| getOrCreateSection(".gcc_except_table", false, SectionKind::getReadOnly()); |
| EHFrameSection = |
| getOrCreateSection(".eh_frame", false, SectionKind::getDataRel()); |
| |
| // Debug Info Sections. |
| DwarfAbbrevSection = |
| getOrCreateSection(".debug_abbrev", false, SectionKind::getMetadata()); |
| DwarfInfoSection = |
| getOrCreateSection(".debug_info", false, SectionKind::getMetadata()); |
| DwarfLineSection = |
| getOrCreateSection(".debug_line", false, SectionKind::getMetadata()); |
| DwarfFrameSection = |
| getOrCreateSection(".debug_frame", false, SectionKind::getMetadata()); |
| DwarfPubNamesSection = |
| getOrCreateSection(".debug_pubnames", false, SectionKind::getMetadata()); |
| DwarfPubTypesSection = |
| getOrCreateSection(".debug_pubtypes", false, SectionKind::getMetadata()); |
| DwarfStrSection = |
| getOrCreateSection(".debug_str", false, SectionKind::getMetadata()); |
| DwarfLocSection = |
| getOrCreateSection(".debug_loc", false, SectionKind::getMetadata()); |
| DwarfARangesSection = |
| getOrCreateSection(".debug_aranges", false, SectionKind::getMetadata()); |
| DwarfRangesSection = |
| getOrCreateSection(".debug_ranges", false, SectionKind::getMetadata()); |
| DwarfMacroInfoSection = |
| getOrCreateSection(".debug_macinfo", false, SectionKind::getMetadata()); |
| } |
| |
| |
| SectionKind TargetLoweringObjectFileELF:: |
| getKindForNamedSection(const char *Name, SectionKind K) const { |
| 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; |
| } |
| |
| void TargetLoweringObjectFileELF:: |
| getSectionFlagsAsString(SectionKind Kind, SmallVectorImpl<char> &Str) const { |
| Str.push_back(','); |
| Str.push_back('"'); |
| |
| if (!Kind.isMetadata()) |
| Str.push_back('a'); |
| if (Kind.isText()) |
| Str.push_back('x'); |
| if (Kind.isWriteable()) |
| Str.push_back('w'); |
| if (Kind.isMergeable1ByteCString() || |
| Kind.isMergeable2ByteCString() || |
| Kind.isMergeable4ByteCString() || |
| Kind.isMergeableConst4() || |
| Kind.isMergeableConst8() || |
| Kind.isMergeableConst16()) |
| Str.push_back('M'); |
| if (Kind.isMergeable1ByteCString() || |
| Kind.isMergeable2ByteCString() || |
| Kind.isMergeable4ByteCString()) |
| Str.push_back('S'); |
| if (Kind.isThreadLocal()) |
| Str.push_back('T'); |
| |
| Str.push_back('"'); |
| Str.push_back(','); |
| |
| // If comment string is '@', e.g. as on ARM - use '%' instead |
| if (AtIsCommentChar) |
| Str.push_back('%'); |
| else |
| Str.push_back('@'); |
| |
| const char *KindStr; |
| if (Kind.isBSS() || Kind.isThreadBSS()) |
| KindStr = "nobits"; |
| else |
| KindStr = "progbits"; |
| |
| Str.append(KindStr, KindStr+strlen(KindStr)); |
| |
| if (Kind.isMergeable1ByteCString()) { |
| Str.push_back(','); |
| Str.push_back('1'); |
| } else if (Kind.isMergeable2ByteCString()) { |
| Str.push_back(','); |
| Str.push_back('2'); |
| } else if (Kind.isMergeable4ByteCString()) { |
| Str.push_back(','); |
| Str.push_back('4'); |
| } else if (Kind.isMergeableConst4()) { |
| Str.push_back(','); |
| Str.push_back('4'); |
| } else if (Kind.isMergeableConst8()) { |
| Str.push_back(','); |
| Str.push_back('8'); |
| } else if (Kind.isMergeableConst16()) { |
| Str.push_back(','); |
| Str.push_back('1'); |
| Str.push_back('6'); |
| } |
| } |
| |
| |
| 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 getOrCreateSection((Prefix+Name).c_str(), false, 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 getOrCreateSection(Name.c_str(), false, Kind); |
| } |
| |
| if (Kind.isMergeableConst()) { |
| if (Kind.isMergeableConst4()) |
| return MergeableConst4Section; |
| if (Kind.isMergeableConst8()) |
| return MergeableConst8Section; |
| if (Kind.isMergeableConst16()) |
| 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()) |
| return MergeableConst4Section; |
| if (Kind.isMergeableConst8()) |
| return MergeableConst8Section; |
| if (Kind.isMergeableConst16()) |
| return MergeableConst16Section; |
| if (Kind.isReadOnly()) |
| return ReadOnlySection; |
| |
| if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection; |
| assert(Kind.isReadOnlyWithRel() && "Unknown section kind"); |
| return DataRelROSection; |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // MachO |
| //===----------------------------------------------------------------------===// |
| |
| const MCSection *TargetLoweringObjectFileMachO:: |
| getMachOSection(const char *Name, bool isDirective, SectionKind K) { |
| // FOR NOW, Just forward. |
| return getOrCreateSection(Name, isDirective, K); |
| } |
| |
| |
| |
| void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx, |
| const TargetMachine &TM) { |
| TargetLoweringObjectFile::Initialize(Ctx, TM); |
| TextSection = getOrCreateSection("\t.text", true, |
| SectionKind::getText()); |
| DataSection = getOrCreateSection("\t.data", true, |
| SectionKind::getDataRel()); |
| |
| CStringSection = getOrCreateSection("\t.cstring", true, |
| SectionKind::getMergeable1ByteCString()); |
| UStringSection = getOrCreateSection("__TEXT,__ustring", false, |
| SectionKind::getMergeable2ByteCString()); |
| FourByteConstantSection = getOrCreateSection("\t.literal4\n", true, |
| SectionKind::getMergeableConst4()); |
| EightByteConstantSection = getOrCreateSection("\t.literal8\n", true, |
| SectionKind::getMergeableConst8()); |
| |
| // ld_classic doesn't support .literal16 in 32-bit mode, and ld64 falls back |
| // to using it in -static mode. |
| if (TM.getRelocationModel() != Reloc::Static && |
| TM.getTargetData()->getPointerSize() == 32) |
| SixteenByteConstantSection = |
| getOrCreateSection("\t.literal16\n", true, |
| SectionKind::getMergeableConst16()); |
| else |
| SixteenByteConstantSection = 0; |
| |
| ReadOnlySection = getOrCreateSection("\t.const", true, |
| SectionKind::getReadOnly()); |
| |
| TextCoalSection = |
| getOrCreateSection("\t__TEXT,__textcoal_nt,coalesced,pure_instructions", |
| false, SectionKind::getText()); |
| ConstTextCoalSection = getOrCreateSection("\t__TEXT,__const_coal,coalesced", |
| false, |
| SectionKind::getText()); |
| ConstDataCoalSection = getOrCreateSection("\t__DATA,__const_coal,coalesced", |
| false, |
| SectionKind::getText()); |
| ConstDataSection = getOrCreateSection("\t.const_data", true, |
| SectionKind::getReadOnlyWithRel()); |
| DataCoalSection = getOrCreateSection("\t__DATA,__datacoal_nt,coalesced", |
| false, |
| SectionKind::getDataRel()); |
| |
| if (TM.getRelocationModel() == Reloc::Static) { |
| StaticCtorSection = |
| getOrCreateSection(".constructor", true, SectionKind::getDataRel()); |
| StaticDtorSection = |
| getOrCreateSection(".destructor", true, SectionKind::getDataRel()); |
| } else { |
| StaticCtorSection = |
| getOrCreateSection(".mod_init_func", true, SectionKind::getDataRel()); |
| StaticDtorSection = |
| getOrCreateSection(".mod_term_func", true, SectionKind::getDataRel()); |
| } |
| |
| // Exception Handling. |
| LSDASection = getOrCreateSection("__DATA,__gcc_except_tab", false, |
| SectionKind::getDataRel()); |
| EHFrameSection = |
| getOrCreateSection("__TEXT,__eh_frame,coalesced,no_toc+strip_static_syms" |
| "+live_support", false, SectionKind::getReadOnly()); |
| |
| // Debug Information. |
| // FIXME: Don't use 'directive' syntax: need flags for debug/regular?? |
| // FIXME: Need __DWARF segment. |
| DwarfAbbrevSection = |
| getOrCreateSection(".section __DWARF,__debug_abbrev,regular,debug", true, |
| SectionKind::getMetadata()); |
| DwarfInfoSection = |
| getOrCreateSection(".section __DWARF,__debug_info,regular,debug", true, |
| SectionKind::getMetadata()); |
| DwarfLineSection = |
| getOrCreateSection(".section __DWARF,__debug_line,regular,debug", true, |
| SectionKind::getMetadata()); |
| DwarfFrameSection = |
| getOrCreateSection(".section __DWARF,__debug_frame,regular,debug", true, |
| SectionKind::getMetadata()); |
| DwarfPubNamesSection = |
| getOrCreateSection(".section __DWARF,__debug_pubnames,regular,debug", true, |
| SectionKind::getMetadata()); |
| DwarfPubTypesSection = |
| getOrCreateSection(".section __DWARF,__debug_pubtypes,regular,debug", true, |
| SectionKind::getMetadata()); |
| DwarfStrSection = |
| getOrCreateSection(".section __DWARF,__debug_str,regular,debug", true, |
| SectionKind::getMetadata()); |
| DwarfLocSection = |
| getOrCreateSection(".section __DWARF,__debug_loc,regular,debug", true, |
| SectionKind::getMetadata()); |
| DwarfARangesSection = |
| getOrCreateSection(".section __DWARF,__debug_aranges,regular,debug", true, |
| SectionKind::getMetadata()); |
| DwarfRangesSection = |
| getOrCreateSection(".section __DWARF,__debug_ranges,regular,debug", true, |
| SectionKind::getMetadata()); |
| DwarfMacroInfoSection = |
| getOrCreateSection(".section __DWARF,__debug_macinfo,regular,debug", true, |
| SectionKind::getMetadata()); |
| DwarfDebugInlineSection = |
| getOrCreateSection(".section __DWARF,__debug_inlined,regular,debug", true, |
| SectionKind::getMetadata()); |
| } |
| |
| 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 |
| //===----------------------------------------------------------------------===// |
| |
| const MCSection *TargetLoweringObjectFileCOFF:: |
| getCOFFSection(const char *Name, bool isDirective, SectionKind K) { |
| return getOrCreateSection(Name, isDirective, K); |
| } |
| |
| void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx, |
| const TargetMachine &TM) { |
| TargetLoweringObjectFile::Initialize(Ctx, TM); |
| TextSection = getOrCreateSection("\t.text", true, |
| SectionKind::getText()); |
| DataSection = getOrCreateSection("\t.data", true, |
| SectionKind::getDataRel()); |
| StaticCtorSection = |
| getOrCreateSection(".ctors", false, SectionKind::getDataRel()); |
| StaticDtorSection = |
| getOrCreateSection(".dtors", false, SectionKind::getDataRel()); |
| |
| |
| // Debug info. |
| // FIXME: Don't use 'directive' mode here. |
| DwarfAbbrevSection = |
| getOrCreateSection("\t.section\t.debug_abbrev,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfInfoSection = |
| getOrCreateSection("\t.section\t.debug_info,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfLineSection = |
| getOrCreateSection("\t.section\t.debug_line,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfFrameSection = |
| getOrCreateSection("\t.section\t.debug_frame,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfPubNamesSection = |
| getOrCreateSection("\t.section\t.debug_pubnames,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfPubTypesSection = |
| getOrCreateSection("\t.section\t.debug_pubtypes,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfStrSection = |
| getOrCreateSection("\t.section\t.debug_str,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfLocSection = |
| getOrCreateSection("\t.section\t.debug_loc,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfARangesSection = |
| getOrCreateSection("\t.section\t.debug_aranges,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfRangesSection = |
| getOrCreateSection("\t.section\t.debug_ranges,\"dr\"", |
| true, SectionKind::getMetadata()); |
| DwarfMacroInfoSection = |
| getOrCreateSection("\t.section\t.debug_macinfo,\"dr\"", |
| true, SectionKind::getMetadata()); |
| } |
| |
| void TargetLoweringObjectFileCOFF:: |
| getSectionFlagsAsString(SectionKind Kind, SmallVectorImpl<char> &Str) const { |
| // FIXME: Inefficient. |
| std::string Res = ",\""; |
| if (Kind.isText()) |
| Res += 'x'; |
| if (Kind.isWriteable()) |
| Res += 'w'; |
| Res += "\""; |
| |
| Str.append(Res.begin(), Res.end()); |
| } |
| |
| 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 getOrCreateSection((Prefix+Name).c_str(), false, Kind); |
| } |
| |
| if (Kind.isText()) |
| return getTextSection(); |
| |
| return getDataSection(); |
| } |
| |