//===-- 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(C->getType()); // First check: is we have constant array of i8 terminated with zero if (const ConstantArray *CVA = dyn_cast(C)) { if (ATy->getNumElements() == 0) return false; ConstantInt *Null = dyn_cast(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(CVA->getOperand(i)) || CVA->getOperand(i) == Null) return false; return true; } // Another possibility: [1 x i8] zeroinitializer if (isa(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(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(C->getType())) { if (const IntegerType *ITy = dyn_cast(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()) { // 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 &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(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(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(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 &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(); }