lib/CodeGen/TargetLoweringObjectFileImpl.cpp

   1 //===-- llvm/CodeGen/TargetLoweringObjectFileImpl.cpp - Object File Info --===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements classes used to handle lowerings specific to common
  11 // object file formats.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
  16 #include "llvm/Constants.h"
  17 #include "llvm/DerivedTypes.h"
  18 #include "llvm/Function.h"
  19 #include "llvm/GlobalVariable.h"
  20 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
  21 #include "llvm/MC/MCContext.h"
  22 #include "llvm/MC/MCExpr.h"
  23 #include "llvm/MC/MCSectionMachO.h"
  24 #include "llvm/MC/MCSectionELF.h"
  25 #include "llvm/MC/MCSectionCOFF.h"
  26 #include "llvm/MC/MCStreamer.h"
  27 #include "llvm/MC/MCSymbol.h"
  28 #include "llvm/Target/Mangler.h"
  29 #include "llvm/Target/TargetData.h"
  30 #include "llvm/Target/TargetMachine.h"
  31 #include "llvm/Target/TargetOptions.h"
  32 #include "llvm/Support/Dwarf.h"
  33 #include "llvm/Support/ELF.h"
  34 #include "llvm/Support/ErrorHandling.h"
  35 #include "llvm/Support/raw_ostream.h"
  36 #include "llvm/ADT/SmallString.h"
  37 #include "llvm/ADT/StringExtras.h"
  38 #include "llvm/ADT/Triple.h"
  39 using namespace llvm;
  40 using namespace dwarf;
  41
  42 //===----------------------------------------------------------------------===//
  43 //                                  ELF
  44 //===----------------------------------------------------------------------===//
  45
  46 void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx,
  47                                              const TargetMachine &TM) {
  48   TargetLoweringObjectFile::Initialize(Ctx, TM);
  49
  50   BSSSection =
  51     getContext().getELFSection(".bss", ELF::SHT_NOBITS,
  52                                ELF::SHF_WRITE |ELF::SHF_ALLOC,
  53                                SectionKind::getBSS());
  54
  55   TextSection =
  56     getContext().getELFSection(".text", ELF::SHT_PROGBITS,
  57                                ELF::SHF_EXECINSTR |
  58                                ELF::SHF_ALLOC,
  59                                SectionKind::getText());
  60
  61   DataSection =
  62     getContext().getELFSection(".data", ELF::SHT_PROGBITS,
  63                                ELF::SHF_WRITE |ELF::SHF_ALLOC,
  64                                SectionKind::getDataRel());
  65
  66   ReadOnlySection =
  67     getContext().getELFSection(".rodata", ELF::SHT_PROGBITS,
  68                                ELF::SHF_ALLOC,
  69                                SectionKind::getReadOnly());
  70
  71   TLSDataSection =
  72     getContext().getELFSection(".tdata", ELF::SHT_PROGBITS,
  73                                ELF::SHF_ALLOC | ELF::SHF_TLS |
  74                                ELF::SHF_WRITE,
  75                                SectionKind::getThreadData());
  76
  77   TLSBSSSection =
  78     getContext().getELFSection(".tbss", ELF::SHT_NOBITS,
  79                                ELF::SHF_ALLOC | ELF::SHF_TLS |
  80                                ELF::SHF_WRITE,
  81                                SectionKind::getThreadBSS());
  82
  83   DataRelSection =
  84     getContext().getELFSection(".data.rel", ELF::SHT_PROGBITS,
  85                                ELF::SHF_ALLOC |ELF::SHF_WRITE,
  86                                SectionKind::getDataRel());
  87
  88   DataRelLocalSection =
  89     getContext().getELFSection(".data.rel.local", ELF::SHT_PROGBITS,
  90                                ELF::SHF_ALLOC |ELF::SHF_WRITE,
  91                                SectionKind::getDataRelLocal());
  92
  93   DataRelROSection =
  94     getContext().getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
  95                                ELF::SHF_ALLOC |ELF::SHF_WRITE,
  96                                SectionKind::getReadOnlyWithRel());
  97
  98   DataRelROLocalSection =
  99     getContext().getELFSection(".data.rel.ro.local", ELF::SHT_PROGBITS,
 100                                ELF::SHF_ALLOC |ELF::SHF_WRITE,
 101                                SectionKind::getReadOnlyWithRelLocal());
 102
 103   MergeableConst4Section =
 104     getContext().getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
 105                                ELF::SHF_ALLOC |ELF::SHF_MERGE,
 106                                SectionKind::getMergeableConst4());
 107
 108   MergeableConst8Section =
 109     getContext().getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
 110                                ELF::SHF_ALLOC |ELF::SHF_MERGE,
 111                                SectionKind::getMergeableConst8());
 112
 113   MergeableConst16Section =
 114     getContext().getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
 115                                ELF::SHF_ALLOC |ELF::SHF_MERGE,
 116                                SectionKind::getMergeableConst16());
 117
 118   StaticCtorSection =
 119     getContext().getELFSection(".ctors", ELF::SHT_PROGBITS,
 120                                ELF::SHF_ALLOC |ELF::SHF_WRITE,
 121                                SectionKind::getDataRel());
 122
 123   StaticDtorSection =
 124     getContext().getELFSection(".dtors", ELF::SHT_PROGBITS,
 125                                ELF::SHF_ALLOC |ELF::SHF_WRITE,
 126                                SectionKind::getDataRel());
 127
 128   // Exception Handling Sections.
 129
 130   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
 131   // it contains relocatable pointers.  In PIC mode, this is probably a big
 132   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
 133   // adjusted or this should be a data section.
 134   LSDASection =
 135     getContext().getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
 136                                ELF::SHF_ALLOC,
 137                                SectionKind::getReadOnly());
 138   // Debug Info Sections.
 139   DwarfAbbrevSection =
 140     getContext().getELFSection(".debug_abbrev", ELF::SHT_PROGBITS, 0,
 141                                SectionKind::getMetadata());
 142   DwarfInfoSection =
 143     getContext().getELFSection(".debug_info", ELF::SHT_PROGBITS, 0,
 144                                SectionKind::getMetadata());
 145   DwarfLineSection =
 146     getContext().getELFSection(".debug_line", ELF::SHT_PROGBITS, 0,
 147                                SectionKind::getMetadata());
 148   DwarfFrameSection =
 149     getContext().getELFSection(".debug_frame", ELF::SHT_PROGBITS, 0,
 150                                SectionKind::getMetadata());
 151   DwarfPubNamesSection =
 152     getContext().getELFSection(".debug_pubnames", ELF::SHT_PROGBITS, 0,
 153                                SectionKind::getMetadata());
 154   DwarfPubTypesSection =
 155     getContext().getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0,
 156                                SectionKind::getMetadata());
 157   DwarfStrSection =
 158     getContext().getELFSection(".debug_str", ELF::SHT_PROGBITS, 0,
 159                                SectionKind::getMetadata());
 160   DwarfLocSection =
 161     getContext().getELFSection(".debug_loc", ELF::SHT_PROGBITS, 0,
 162                                SectionKind::getMetadata());
 163   DwarfARangesSection =
 164     getContext().getELFSection(".debug_aranges", ELF::SHT_PROGBITS, 0,
 165                                SectionKind::getMetadata());
 166   DwarfRangesSection =
 167     getContext().getELFSection(".debug_ranges", ELF::SHT_PROGBITS, 0,
 168                                SectionKind::getMetadata());
 169   DwarfMacroInfoSection =
 170     getContext().getELFSection(".debug_macinfo", ELF::SHT_PROGBITS, 0,
 171                                SectionKind::getMetadata());
 172 }
 173
 174 const MCSection *TargetLoweringObjectFileELF::getEHFrameSection() const {
 175   return getContext().getELFSection(".eh_frame", ELF::SHT_PROGBITS,
 176                                     ELF::SHF_ALLOC,
 177                                     SectionKind::getDataRel());
 178 }
 179
 180 MCSymbol *
 181 TargetLoweringObjectFileELF::getCFIPersonalitySymbol(const GlobalValue *GV,
 182                                                      Mangler *Mang,
 183                                                 MachineModuleInfo *MMI) const {
 184   unsigned Encoding = getPersonalityEncoding();
 185   switch (Encoding & 0x70) {
 186   default:
 187     report_fatal_error("We do not support this DWARF encoding yet!");
 188   case dwarf::DW_EH_PE_absptr:
 189     return  Mang->getSymbol(GV);
 190     break;
 191   case dwarf::DW_EH_PE_pcrel: {
 192     Twine FullName = StringRef("DW.ref.") + Mang->getSymbol(GV)->getName();
 193     return getContext().GetOrCreateSymbol(FullName);
 194     break;
 195   }
 196   }
 197 }
 198
 199 void TargetLoweringObjectFileELF::emitPersonalityValue(MCStreamer &Streamer,
 200                                                        const TargetMachine &TM,
 201                                                        const MCSymbol *Sym) const {
 202   Twine FullName = StringRef("DW.ref.") + Sym->getName();
 203   MCSymbol *Label = getContext().GetOrCreateSymbol(FullName);
 204   Streamer.EmitSymbolAttribute(Label, MCSA_Hidden);
 205   Streamer.EmitSymbolAttribute(Label, MCSA_Weak);
 206   Twine SectionName = StringRef(".data.") + Label->getName();
 207   SmallString<64> NameData;
 208   SectionName.toVector(NameData);
 209   unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_GROUP;
 210   const MCSection *Sec = getContext().getELFSection(NameData,
 211                                                     ELF::SHT_PROGBITS,
 212                                                     Flags,
 213                                                     SectionKind::getDataRel(),
 214                                                     0, Label->getName());
 215   Streamer.SwitchSection(Sec);
 216   Streamer.EmitValueToAlignment(8);
 217   Streamer.EmitSymbolAttribute(Label, MCSA_ELF_TypeObject);
 218   const MCExpr *E = MCConstantExpr::Create(8, getContext());
 219   Streamer.EmitELFSize(Label, E);
 220   Streamer.EmitLabel(Label);
 221
 222   unsigned Size = TM.getTargetData()->getPointerSize();
 223   Streamer.EmitSymbolValue(Sym, Size);
 224 }
 225
 226 static SectionKind
 227 getELFKindForNamedSection(StringRef Name, SectionKind K) {
 228   // FIXME: Why is this here? Codegen is should not be in the business
 229   // of figuring section flags. If the user wrote section(".eh_frame"),
 230   // we should just pass that to MC which will defer to the assembly
 231   // or use its default if producing an object file.
 232   if (Name.empty() || Name[0] != '.') return K;
 233
 234   // Some lame default implementation based on some magic section names.
 235   if (Name == ".bss" ||
 236       Name.startswith(".bss.") ||
 237       Name.startswith(".gnu.linkonce.b.") ||
 238       Name.startswith(".llvm.linkonce.b.") ||
 239       Name == ".sbss" ||
 240       Name.startswith(".sbss.") ||
 241       Name.startswith(".gnu.linkonce.sb.") ||
 242       Name.startswith(".llvm.linkonce.sb."))
 243     return SectionKind::getBSS();
 244
 245   if (Name == ".tdata" ||
 246       Name.startswith(".tdata.") ||
 247       Name.startswith(".gnu.linkonce.td.") ||
 248       Name.startswith(".llvm.linkonce.td."))
 249     return SectionKind::getThreadData();
 250
 251   if (Name == ".tbss" ||
 252       Name.startswith(".tbss.") ||
 253       Name.startswith(".gnu.linkonce.tb.") ||
 254       Name.startswith(".llvm.linkonce.tb."))
 255     return SectionKind::getThreadBSS();
 256
 257   if (Name == ".eh_frame")
 258     return SectionKind::getDataRel();
 259
 260   return K;
 261 }
 262
 263
 264 static unsigned getELFSectionType(StringRef Name, SectionKind K) {
 265
 266   if (Name == ".init_array")
 267     return ELF::SHT_INIT_ARRAY;
 268
 269   if (Name == ".fini_array")
 270     return ELF::SHT_FINI_ARRAY;
 271
 272   if (Name == ".preinit_array")
 273     return ELF::SHT_PREINIT_ARRAY;
 274
 275   if (K.isBSS() || K.isThreadBSS())
 276     return ELF::SHT_NOBITS;
 277
 278   return ELF::SHT_PROGBITS;
 279 }
 280
 281
 282 static unsigned
 283 getELFSectionFlags(SectionKind K) {
 284   unsigned Flags = 0;
 285
 286   if (!K.isMetadata())
 287     Flags |= ELF::SHF_ALLOC;
 288
 289   if (K.isText())
 290     Flags |= ELF::SHF_EXECINSTR;
 291
 292   if (K.isWriteable())
 293     Flags |= ELF::SHF_WRITE;
 294
 295   if (K.isThreadLocal())
 296     Flags |= ELF::SHF_TLS;
 297
 298   // K.isMergeableConst() is left out to honour PR4650
 299   if (K.isMergeableCString() || K.isMergeableConst4() ||
 300       K.isMergeableConst8() || K.isMergeableConst16())
 301     Flags |= ELF::SHF_MERGE;
 302
 303   if (K.isMergeableCString())
 304     Flags |= ELF::SHF_STRINGS;
 305
 306   return Flags;
 307 }
 308
 309
 310 const MCSection *TargetLoweringObjectFileELF::
 311 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
 312                          Mangler *Mang, const TargetMachine &TM) const {
 313   StringRef SectionName = GV->getSection();
 314
 315   // Infer section flags from the section name if we can.
 316   Kind = getELFKindForNamedSection(SectionName, Kind);
 317
 318   return getContext().getELFSection(SectionName,
 319                                     getELFSectionType(SectionName, Kind),
 320                                     getELFSectionFlags(Kind), Kind);
 321 }
 322
 323 /// getSectionPrefixForGlobal - Return the section prefix name used by options
 324 /// FunctionsSections and DataSections.
 325 static const char *getSectionPrefixForGlobal(SectionKind Kind) {
 326   if (Kind.isText())                 return ".text.";
 327   if (Kind.isReadOnly())             return ".rodata.";
 328
 329   if (Kind.isThreadData())           return ".tdata.";
 330   if (Kind.isThreadBSS())            return ".tbss.";
 331
 332   if (Kind.isDataNoRel())            return ".data.";
 333   if (Kind.isDataRelLocal())         return ".data.rel.local.";
 334   if (Kind.isDataRel())              return ".data.rel.";
 335   if (Kind.isReadOnlyWithRelLocal()) return ".data.rel.ro.local.";
 336
 337   assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
 338   return ".data.rel.ro.";
 339 }
 340
 341
 342 const MCSection *TargetLoweringObjectFileELF::
 343 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
 344                        Mangler *Mang, const TargetMachine &TM) const {
 345   // If we have -ffunction-section or -fdata-section then we should emit the
 346   // global value to a uniqued section specifically for it.
 347   bool EmitUniquedSection;
 348   if (Kind.isText())
 349     EmitUniquedSection = TM.getFunctionSections();
 350   else
 351     EmitUniquedSection = TM.getDataSections();
 352
 353   // If this global is linkonce/weak and the target handles this by emitting it
 354   // into a 'uniqued' section name, create and return the section now.
 355   if ((GV->isWeakForLinker() || EmitUniquedSection) &&
 356       !Kind.isCommon() && !Kind.isBSS()) {
 357     const char *Prefix;
 358     Prefix = getSectionPrefixForGlobal(Kind);
 359
 360     SmallString<128> Name(Prefix, Prefix+strlen(Prefix));
 361     MCSymbol *Sym = Mang->getSymbol(GV);
 362     Name.append(Sym->getName().begin(), Sym->getName().end());
 363     StringRef Group = "";
 364     unsigned Flags = getELFSectionFlags(Kind);
 365     if (GV->isWeakForLinker()) {
 366       Group = Sym->getName();
 367       Flags |= ELF::SHF_GROUP;
 368     }
 369
 370     return getContext().getELFSection(Name.str(),
 371                                       getELFSectionType(Name.str(), Kind),
 372                                       Flags, Kind, 0, Group);
 373   }
 374
 375   if (Kind.isText()) return TextSection;
 376
 377   if (Kind.isMergeable1ByteCString() ||
 378       Kind.isMergeable2ByteCString() ||
 379       Kind.isMergeable4ByteCString()) {
 380
 381     // We also need alignment here.
 382     // FIXME: this is getting the alignment of the character, not the
 383     // alignment of the global!
 384     unsigned Align =
 385       TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV));
 386
 387     const char *SizeSpec = ".rodata.str1.";
 388     if (Kind.isMergeable2ByteCString())
 389       SizeSpec = ".rodata.str2.";
 390     else if (Kind.isMergeable4ByteCString())
 391       SizeSpec = ".rodata.str4.";
 392     else
 393       assert(Kind.isMergeable1ByteCString() && "unknown string width");
 394
 395
 396     std::string Name = SizeSpec + utostr(Align);
 397     return getContext().getELFSection(Name, ELF::SHT_PROGBITS,
 398                                       ELF::SHF_ALLOC |
 399                                       ELF::SHF_MERGE |
 400                                       ELF::SHF_STRINGS,
 401                                       Kind);
 402   }
 403
 404   if (Kind.isMergeableConst()) {
 405     if (Kind.isMergeableConst4() && MergeableConst4Section)
 406       return MergeableConst4Section;
 407     if (Kind.isMergeableConst8() && MergeableConst8Section)
 408       return MergeableConst8Section;
 409     if (Kind.isMergeableConst16() && MergeableConst16Section)
 410       return MergeableConst16Section;
 411     return ReadOnlySection;  // .const
 412   }
 413
 414   if (Kind.isReadOnly())             return ReadOnlySection;
 415
 416   if (Kind.isThreadData())           return TLSDataSection;
 417   if (Kind.isThreadBSS())            return TLSBSSSection;
 418
 419   // Note: we claim that common symbols are put in BSSSection, but they are
 420   // really emitted with the magic .comm directive, which creates a symbol table
 421   // entry but not a section.
 422   if (Kind.isBSS() || Kind.isCommon()) return BSSSection;
 423
 424   if (Kind.isDataNoRel())            return DataSection;
 425   if (Kind.isDataRelLocal())         return DataRelLocalSection;
 426   if (Kind.isDataRel())              return DataRelSection;
 427   if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
 428
 429   assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
 430   return DataRelROSection;
 431 }
 432
 433 /// getSectionForConstant - Given a mergeable constant with the
 434 /// specified size and relocation information, return a section that it
 435 /// should be placed in.
 436 const MCSection *TargetLoweringObjectFileELF::
 437 getSectionForConstant(SectionKind Kind) const {
 438   if (Kind.isMergeableConst4() && MergeableConst4Section)
 439     return MergeableConst4Section;
 440   if (Kind.isMergeableConst8() && MergeableConst8Section)
 441     return MergeableConst8Section;
 442   if (Kind.isMergeableConst16() && MergeableConst16Section)
 443     return MergeableConst16Section;
 444   if (Kind.isReadOnly())
 445     return ReadOnlySection;
 446
 447   if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
 448   assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
 449   return DataRelROSection;
 450 }
 451
 452 const MCExpr *TargetLoweringObjectFileELF::
 453 getExprForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
 454                                MachineModuleInfo *MMI,
 455                                unsigned Encoding, MCStreamer &Streamer) const {
 456
 457   if (Encoding & dwarf::DW_EH_PE_indirect) {
 458     MachineModuleInfoELF &ELFMMI = MMI->getObjFileInfo<MachineModuleInfoELF>();
 459
 460     SmallString<128> Name;
 461     Mang->getNameWithPrefix(Name, GV, true);
 462     Name += ".DW.stub";
 463
 464     // Add information about the stub reference to ELFMMI so that the stub
 465     // gets emitted by the asmprinter.
 466     MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str());
 467     MachineModuleInfoImpl::StubValueTy &StubSym = ELFMMI.getGVStubEntry(SSym);
 468     if (StubSym.getPointer() == 0) {
 469       MCSymbol *Sym = Mang->getSymbol(GV);
 470       StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
 471     }
 472
 473     return TargetLoweringObjectFile::
 474       getExprForDwarfReference(SSym, Encoding & ~dwarf::DW_EH_PE_indirect, Streamer);
 475   }
 476
 477   return TargetLoweringObjectFile::
 478     getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer);
 479 }
 480
 481 //===----------------------------------------------------------------------===//
 482 //                                 MachO
 483 //===----------------------------------------------------------------------===//
 484
 485 void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx,
 486                                                const TargetMachine &TM) {
 487   // _foo.eh symbols are currently always exported so that the linker knows
 488   // about them.  This is not necessary on 10.6 and later, but it
 489   // doesn't hurt anything.
 490   // FIXME: I need to get this from Triple.
 491   IsFunctionEHSymbolGlobal = true;
 492   IsFunctionEHFrameSymbolPrivate = false;
 493   SupportsWeakOmittedEHFrame = false;
 494
 495   // .comm doesn't support alignment before Leopard.
 496   Triple T(((LLVMTargetMachine&)TM).getTargetTriple());
 497   if (T.isMacOSX() && T.isMacOSXVersionLT(10, 5))
 498     CommDirectiveSupportsAlignment = false;
 499
 500   TargetLoweringObjectFile::Initialize(Ctx, TM);
 501
 502   TextSection // .text
 503     = getContext().getMachOSection("__TEXT", "__text",
 504                                    MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
 505                                    SectionKind::getText());
 506   DataSection // .data
 507     = getContext().getMachOSection("__DATA", "__data", 0,
 508                                    SectionKind::getDataRel());
 509
 510   TLSDataSection // .tdata
 511     = getContext().getMachOSection("__DATA", "__thread_data",
 512                                    MCSectionMachO::S_THREAD_LOCAL_REGULAR,
 513                                    SectionKind::getDataRel());
 514   TLSBSSSection // .tbss
 515     = getContext().getMachOSection("__DATA", "__thread_bss",
 516                                    MCSectionMachO::S_THREAD_LOCAL_ZEROFILL,
 517                                    SectionKind::getThreadBSS());
 518
 519   // TODO: Verify datarel below.
 520   TLSTLVSection // .tlv
 521     = getContext().getMachOSection("__DATA", "__thread_vars",
 522                                    MCSectionMachO::S_THREAD_LOCAL_VARIABLES,
 523                                    SectionKind::getDataRel());
 524
 525   TLSThreadInitSection
 526     = getContext().getMachOSection("__DATA", "__thread_init",
 527                           MCSectionMachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
 528                           SectionKind::getDataRel());
 529
 530   CStringSection // .cstring
 531     = getContext().getMachOSection("__TEXT", "__cstring",
 532                                    MCSectionMachO::S_CSTRING_LITERALS,
 533                                    SectionKind::getMergeable1ByteCString());
 534   UStringSection
 535     = getContext().getMachOSection("__TEXT","__ustring", 0,
 536                                    SectionKind::getMergeable2ByteCString());
 537   FourByteConstantSection // .literal4
 538     = getContext().getMachOSection("__TEXT", "__literal4",
 539                                    MCSectionMachO::S_4BYTE_LITERALS,
 540                                    SectionKind::getMergeableConst4());
 541   EightByteConstantSection // .literal8
 542     = getContext().getMachOSection("__TEXT", "__literal8",
 543                                    MCSectionMachO::S_8BYTE_LITERALS,
 544                                    SectionKind::getMergeableConst8());
 545
 546   // ld_classic doesn't support .literal16 in 32-bit mode, and ld64 falls back
 547   // to using it in -static mode.
 548   SixteenByteConstantSection = 0;
 549   if (TM.getRelocationModel() != Reloc::Static &&
 550       TM.getTargetData()->getPointerSize() == 32)
 551     SixteenByteConstantSection =   // .literal16
 552       getContext().getMachOSection("__TEXT", "__literal16",
 553                                    MCSectionMachO::S_16BYTE_LITERALS,
 554                                    SectionKind::getMergeableConst16());
 555
 556   ReadOnlySection  // .const
 557     = getContext().getMachOSection("__TEXT", "__const", 0,
 558                                    SectionKind::getReadOnly());
 559
 560   TextCoalSection
 561     = getContext().getMachOSection("__TEXT", "__textcoal_nt",
 562                                    MCSectionMachO::S_COALESCED |
 563                                    MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
 564                                    SectionKind::getText());
 565   ConstTextCoalSection
 566     = getContext().getMachOSection("__TEXT", "__const_coal",
 567                                    MCSectionMachO::S_COALESCED,
 568                                    SectionKind::getReadOnly());
 569   ConstDataSection  // .const_data
 570     = getContext().getMachOSection("__DATA", "__const", 0,
 571                                    SectionKind::getReadOnlyWithRel());
 572   DataCoalSection
 573     = getContext().getMachOSection("__DATA","__datacoal_nt",
 574                                    MCSectionMachO::S_COALESCED,
 575                                    SectionKind::getDataRel());
 576   DataCommonSection
 577     = getContext().getMachOSection("__DATA","__common",
 578                                    MCSectionMachO::S_ZEROFILL,
 579                                    SectionKind::getBSS());
 580   DataBSSSection
 581     = getContext().getMachOSection("__DATA","__bss", MCSectionMachO::S_ZEROFILL,
 582                                    SectionKind::getBSS());
 583
 584
 585   LazySymbolPointerSection
 586     = getContext().getMachOSection("__DATA", "__la_symbol_ptr",
 587                                    MCSectionMachO::S_LAZY_SYMBOL_POINTERS,
 588                                    SectionKind::getMetadata());
 589   NonLazySymbolPointerSection
 590     = getContext().getMachOSection("__DATA", "__nl_symbol_ptr",
 591                                    MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS,
 592                                    SectionKind::getMetadata());
 593
 594   if (TM.getRelocationModel() == Reloc::Static) {
 595     StaticCtorSection
 596       = getContext().getMachOSection("__TEXT", "__constructor", 0,
 597                                      SectionKind::getDataRel());
 598     StaticDtorSection
 599       = getContext().getMachOSection("__TEXT", "__destructor", 0,
 600                                      SectionKind::getDataRel());
 601   } else {
 602     StaticCtorSection
 603       = getContext().getMachOSection("__DATA", "__mod_init_func",
 604                                      MCSectionMachO::S_MOD_INIT_FUNC_POINTERS,
 605                                      SectionKind::getDataRel());
 606     StaticDtorSection
 607       = getContext().getMachOSection("__DATA", "__mod_term_func",
 608                                      MCSectionMachO::S_MOD_TERM_FUNC_POINTERS,
 609                                      SectionKind::getDataRel());
 610   }
 611
 612   // Exception Handling.
 613   LSDASection = getContext().getMachOSection("__TEXT", "__gcc_except_tab", 0,
 614                                              SectionKind::getReadOnlyWithRel());
 615   // Debug Information.
 616   DwarfAbbrevSection =
 617     getContext().getMachOSection("__DWARF", "__debug_abbrev",
 618                                  MCSectionMachO::S_ATTR_DEBUG,
 619                                  SectionKind::getMetadata());
 620   DwarfInfoSection =
 621     getContext().getMachOSection("__DWARF", "__debug_info",
 622                                  MCSectionMachO::S_ATTR_DEBUG,
 623                                  SectionKind::getMetadata());
 624   DwarfLineSection =
 625     getContext().getMachOSection("__DWARF", "__debug_line",
 626                                  MCSectionMachO::S_ATTR_DEBUG,
 627                                  SectionKind::getMetadata());
 628   DwarfFrameSection =
 629     getContext().getMachOSection("__DWARF", "__debug_frame",
 630                                  MCSectionMachO::S_ATTR_DEBUG,
 631                                  SectionKind::getMetadata());
 632   DwarfPubNamesSection =
 633     getContext().getMachOSection("__DWARF", "__debug_pubnames",
 634                                  MCSectionMachO::S_ATTR_DEBUG,
 635                                  SectionKind::getMetadata());
 636   DwarfPubTypesSection =
 637     getContext().getMachOSection("__DWARF", "__debug_pubtypes",
 638                                  MCSectionMachO::S_ATTR_DEBUG,
 639                                  SectionKind::getMetadata());
 640   DwarfStrSection =
 641     getContext().getMachOSection("__DWARF", "__debug_str",
 642                                  MCSectionMachO::S_ATTR_DEBUG,
 643                                  SectionKind::getMetadata());
 644   DwarfLocSection =
 645     getContext().getMachOSection("__DWARF", "__debug_loc",
 646                                  MCSectionMachO::S_ATTR_DEBUG,
 647                                  SectionKind::getMetadata());
 648   DwarfARangesSection =
 649     getContext().getMachOSection("__DWARF", "__debug_aranges",
 650                                  MCSectionMachO::S_ATTR_DEBUG,
 651                                  SectionKind::getMetadata());
 652   DwarfRangesSection =
 653     getContext().getMachOSection("__DWARF", "__debug_ranges",
 654                                  MCSectionMachO::S_ATTR_DEBUG,
 655                                  SectionKind::getMetadata());
 656   DwarfMacroInfoSection =
 657     getContext().getMachOSection("__DWARF", "__debug_macinfo",
 658                                  MCSectionMachO::S_ATTR_DEBUG,
 659                                  SectionKind::getMetadata());
 660   DwarfDebugInlineSection =
 661     getContext().getMachOSection("__DWARF", "__debug_inlined",
 662                                  MCSectionMachO::S_ATTR_DEBUG,
 663                                  SectionKind::getMetadata());
 664
 665   TLSExtraDataSection = TLSTLVSection;
 666 }
 667
 668 const MCSection *TargetLoweringObjectFileMachO::getEHFrameSection() const {
 669   return getContext().getMachOSection("__TEXT", "__eh_frame",
 670                                       MCSectionMachO::S_COALESCED |
 671                                       MCSectionMachO::S_ATTR_NO_TOC |
 672                                       MCSectionMachO::S_ATTR_STRIP_STATIC_SYMS |
 673                                       MCSectionMachO::S_ATTR_LIVE_SUPPORT,
 674                                       SectionKind::getReadOnly());
 675 }
 676
 677 const MCSection *TargetLoweringObjectFileMachO::
 678 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
 679                          Mangler *Mang, const TargetMachine &TM) const {
 680   // Parse the section specifier and create it if valid.
 681   StringRef Segment, Section;
 682   unsigned TAA = 0, StubSize = 0;
 683   bool TAAParsed;
 684   std::string ErrorCode =
 685     MCSectionMachO::ParseSectionSpecifier(GV->getSection(), Segment, Section,
 686                                           TAA, TAAParsed, StubSize);
 687   if (!ErrorCode.empty()) {
 688     // If invalid, report the error with report_fatal_error.
 689     report_fatal_error("Global variable '" + GV->getNameStr() +
 690                       "' has an invalid section specifier '" + GV->getSection()+
 691                       "': " + ErrorCode + ".");
 692     // Fall back to dropping it into the data section.
 693     return DataSection;
 694   }
 695
 696   // Get the section.
 697   const MCSectionMachO *S =
 698     getContext().getMachOSection(Segment, Section, TAA, StubSize, Kind);
 699
 700   // If TAA wasn't set by ParseSectionSpecifier() above,
 701   // use the value returned by getMachOSection() as a default.
 702   if (!TAAParsed)
 703     TAA = S->getTypeAndAttributes();
 704
 705   // Okay, now that we got the section, verify that the TAA & StubSize agree.
 706   // If the user declared multiple globals with different section flags, we need
 707   // to reject it here.
 708   if (S->getTypeAndAttributes() != TAA || S->getStubSize() != StubSize) {
 709     // If invalid, report the error with report_fatal_error.
 710     report_fatal_error("Global variable '" + GV->getNameStr() +
 711                       "' section type or attributes does not match previous"
 712                       " section specifier");
 713   }
 714
 715   return S;
 716 }
 717
 718 const MCSection *TargetLoweringObjectFileMachO::
 719 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
 720                        Mangler *Mang, const TargetMachine &TM) const {
 721
 722   // Handle thread local data.
 723   if (Kind.isThreadBSS()) return TLSBSSSection;
 724   if (Kind.isThreadData()) return TLSDataSection;
 725
 726   if (Kind.isText())
 727     return GV->isWeakForLinker() ? TextCoalSection : TextSection;
 728
 729   // If this is weak/linkonce, put this in a coalescable section, either in text
 730   // or data depending on if it is writable.
 731   if (GV->isWeakForLinker()) {
 732     if (Kind.isReadOnly())
 733       return ConstTextCoalSection;
 734     return DataCoalSection;
 735   }
 736
 737   // FIXME: Alignment check should be handled by section classifier.
 738   if (Kind.isMergeable1ByteCString() &&
 739       TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV)) < 32)
 740     return CStringSection;
 741
 742   // Do not put 16-bit arrays in the UString section if they have an
 743   // externally visible label, this runs into issues with certain linker
 744   // versions.
 745   if (Kind.isMergeable2ByteCString() && !GV->hasExternalLinkage() &&
 746       TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV)) < 32)
 747     return UStringSection;
 748
 749   if (Kind.isMergeableConst()) {
 750     if (Kind.isMergeableConst4())
 751       return FourByteConstantSection;
 752     if (Kind.isMergeableConst8())
 753       return EightByteConstantSection;
 754     if (Kind.isMergeableConst16() && SixteenByteConstantSection)
 755       return SixteenByteConstantSection;
 756   }
 757
 758   // Otherwise, if it is readonly, but not something we can specially optimize,
 759   // just drop it in .const.
 760   if (Kind.isReadOnly())
 761     return ReadOnlySection;
 762
 763   // If this is marked const, put it into a const section.  But if the dynamic
 764   // linker needs to write to it, put it in the data segment.
 765   if (Kind.isReadOnlyWithRel())
 766     return ConstDataSection;
 767
 768   // Put zero initialized globals with strong external linkage in the
 769   // DATA, __common section with the .zerofill directive.
 770   if (Kind.isBSSExtern())
 771     return DataCommonSection;
 772
 773   // Put zero initialized globals with local linkage in __DATA,__bss directive
 774   // with the .zerofill directive (aka .lcomm).
 775   if (Kind.isBSSLocal())
 776     return DataBSSSection;
 777
 778   // Otherwise, just drop the variable in the normal data section.
 779   return DataSection;
 780 }
 781
 782 const MCSection *
 783 TargetLoweringObjectFileMachO::getSectionForConstant(SectionKind Kind) const {
 784   // If this constant requires a relocation, we have to put it in the data
 785   // segment, not in the text segment.
 786   if (Kind.isDataRel() || Kind.isReadOnlyWithRel())
 787     return ConstDataSection;
 788
 789   if (Kind.isMergeableConst4())
 790     return FourByteConstantSection;
 791   if (Kind.isMergeableConst8())
 792     return EightByteConstantSection;
 793   if (Kind.isMergeableConst16() && SixteenByteConstantSection)
 794     return SixteenByteConstantSection;
 795   return ReadOnlySection;  // .const
 796 }
 797
 798 /// shouldEmitUsedDirectiveFor - This hook allows targets to selectively decide
 799 /// not to emit the UsedDirective for some symbols in llvm.used.
 800 // FIXME: REMOVE this (rdar://7071300)
 801 bool TargetLoweringObjectFileMachO::
 802 shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler *Mang) const {
 803   /// On Darwin, internally linked data beginning with "L" or "l" does not have
 804   /// the directive emitted (this occurs in ObjC metadata).
 805   if (!GV) return false;
 806
 807   // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix.
 808   if (GV->hasLocalLinkage() && !isa<Function>(GV)) {
 809     // FIXME: ObjC metadata is currently emitted as internal symbols that have
 810     // \1L and \0l prefixes on them.  Fix them to be Private/LinkerPrivate and
 811     // this horrible hack can go away.
 812     MCSymbol *Sym = Mang->getSymbol(GV);
 813     if (Sym->getName()[0] == 'L' || Sym->getName()[0] == 'l')
 814       return false;
 815   }
 816
 817   return true;
 818 }
 819
 820 const MCExpr *TargetLoweringObjectFileMachO::
 821 getExprForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
 822                                MachineModuleInfo *MMI, unsigned Encoding,
 823                                MCStreamer &Streamer) const {
 824   // The mach-o version of this method defaults to returning a stub reference.
 825
 826   if (Encoding & DW_EH_PE_indirect) {
 827     MachineModuleInfoMachO &MachOMMI =
 828       MMI->getObjFileInfo<MachineModuleInfoMachO>();
 829
 830     SmallString<128> Name;
 831     Mang->getNameWithPrefix(Name, GV, true);
 832     Name += "$non_lazy_ptr";
 833
 834     // Add information about the stub reference to MachOMMI so that the stub
 835     // gets emitted by the asmprinter.
 836     MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str());
 837     MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(SSym);
 838     if (StubSym.getPointer() == 0) {
 839       MCSymbol *Sym = Mang->getSymbol(GV);
 840       StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
 841     }
 842
 843     return TargetLoweringObjectFile::
 844       getExprForDwarfReference(SSym, Encoding & ~dwarf::DW_EH_PE_indirect, Streamer);
 845   }
 846
 847   return TargetLoweringObjectFile::
 848     getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer);
 849 }
 850
 851 MCSymbol *TargetLoweringObjectFileMachO::
 852 getCFIPersonalitySymbol(const GlobalValue *GV, Mangler *Mang,
 853                         MachineModuleInfo *MMI) const {
 854   // The mach-o version of this method defaults to returning a stub reference.
 855   MachineModuleInfoMachO &MachOMMI =
 856     MMI->getObjFileInfo<MachineModuleInfoMachO>();
 857
 858   SmallString<128> Name;
 859   Mang->getNameWithPrefix(Name, GV, true);
 860   Name += "$non_lazy_ptr";
 861
 862   // Add information about the stub reference to MachOMMI so that the stub
 863   // gets emitted by the asmprinter.
 864   MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str());
 865   MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(SSym);
 866   if (StubSym.getPointer() == 0) {
 867     MCSymbol *Sym = Mang->getSymbol(GV);
 868     StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
 869   }
 870
 871   return SSym;
 872 }
 873
 874 unsigned TargetLoweringObjectFileMachO::getPersonalityEncoding() const {
 875   return DW_EH_PE_indirect | DW_EH_PE_pcrel | DW_EH_PE_sdata4;
 876 }
 877
 878 unsigned TargetLoweringObjectFileMachO::getLSDAEncoding() const {
 879   return DW_EH_PE_pcrel;
 880 }
 881
 882 unsigned TargetLoweringObjectFileMachO::getFDEEncoding(bool CFI) const {
 883   return DW_EH_PE_pcrel;
 884 }
 885
 886 unsigned TargetLoweringObjectFileMachO::getTTypeEncoding() const {
 887   return DW_EH_PE_indirect | DW_EH_PE_pcrel | DW_EH_PE_sdata4;
 888 }
 889
 890 //===----------------------------------------------------------------------===//
 891 //                                  COFF
 892 //===----------------------------------------------------------------------===//
 893
 894 void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx,
 895                                               const TargetMachine &TM) {
 896   TargetLoweringObjectFile::Initialize(Ctx, TM);
 897   TextSection =
 898     getContext().getCOFFSection(".text",
 899                                 COFF::IMAGE_SCN_CNT_CODE |
 900                                 COFF::IMAGE_SCN_MEM_EXECUTE |
 901                                 COFF::IMAGE_SCN_MEM_READ,
 902                                 SectionKind::getText());
 903   DataSection =
 904     getContext().getCOFFSection(".data",
 905                                 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 906                                 COFF::IMAGE_SCN_MEM_READ |
 907                                 COFF::IMAGE_SCN_MEM_WRITE,
 908                                 SectionKind::getDataRel());
 909   ReadOnlySection =
 910     getContext().getCOFFSection(".rdata",
 911                                 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 912                                 COFF::IMAGE_SCN_MEM_READ,
 913                                 SectionKind::getReadOnly());
 914   StaticCtorSection =
 915     getContext().getCOFFSection(".ctors",
 916                                 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 917                                 COFF::IMAGE_SCN_MEM_READ |
 918                                 COFF::IMAGE_SCN_MEM_WRITE,
 919                                 SectionKind::getDataRel());
 920   StaticDtorSection =
 921     getContext().getCOFFSection(".dtors",
 922                                 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 923                                 COFF::IMAGE_SCN_MEM_READ |
 924                                 COFF::IMAGE_SCN_MEM_WRITE,
 925                                 SectionKind::getDataRel());
 926
 927   // FIXME: We're emitting LSDA info into a readonly section on COFF, even
 928   // though it contains relocatable pointers.  In PIC mode, this is probably a
 929   // big runtime hit for C++ apps.  Either the contents of the LSDA need to be
 930   // adjusted or this should be a data section.
 931   LSDASection =
 932     getContext().getCOFFSection(".gcc_except_table",
 933                                 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 934                                 COFF::IMAGE_SCN_MEM_READ,
 935                                 SectionKind::getReadOnly());
 936   // Debug info.
 937   DwarfAbbrevSection =
 938     getContext().getCOFFSection(".debug_abbrev",
 939                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
 940                                 COFF::IMAGE_SCN_MEM_READ,
 941                                 SectionKind::getMetadata());
 942   DwarfInfoSection =
 943     getContext().getCOFFSection(".debug_info",
 944                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
 945                                 COFF::IMAGE_SCN_MEM_READ,
 946                                 SectionKind::getMetadata());
 947   DwarfLineSection =
 948     getContext().getCOFFSection(".debug_line",
 949                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
 950                                 COFF::IMAGE_SCN_MEM_READ,
 951                                 SectionKind::getMetadata());
 952   DwarfFrameSection =
 953     getContext().getCOFFSection(".debug_frame",
 954                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
 955                                 COFF::IMAGE_SCN_MEM_READ,
 956                                 SectionKind::getMetadata());
 957   DwarfPubNamesSection =
 958     getContext().getCOFFSection(".debug_pubnames",
 959                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
 960                                 COFF::IMAGE_SCN_MEM_READ,
 961                                 SectionKind::getMetadata());
 962   DwarfPubTypesSection =
 963     getContext().getCOFFSection(".debug_pubtypes",
 964                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
 965                                 COFF::IMAGE_SCN_MEM_READ,
 966                                 SectionKind::getMetadata());
 967   DwarfStrSection =
 968     getContext().getCOFFSection(".debug_str",
 969                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
 970                                 COFF::IMAGE_SCN_MEM_READ,
 971                                 SectionKind::getMetadata());
 972   DwarfLocSection =
 973     getContext().getCOFFSection(".debug_loc",
 974                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
 975                                 COFF::IMAGE_SCN_MEM_READ,
 976                                 SectionKind::getMetadata());
 977   DwarfARangesSection =
 978     getContext().getCOFFSection(".debug_aranges",
 979                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
 980                                 COFF::IMAGE_SCN_MEM_READ,
 981                                 SectionKind::getMetadata());
 982   DwarfRangesSection =
 983     getContext().getCOFFSection(".debug_ranges",
 984                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
 985                                 COFF::IMAGE_SCN_MEM_READ,
 986                                 SectionKind::getMetadata());
 987   DwarfMacroInfoSection =
 988     getContext().getCOFFSection(".debug_macinfo",
 989                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
 990                                 COFF::IMAGE_SCN_MEM_READ,
 991                                 SectionKind::getMetadata());
 992
 993   DrectveSection =
 994     getContext().getCOFFSection(".drectve",
 995                                 COFF::IMAGE_SCN_LNK_INFO,
 996                                 SectionKind::getMetadata());
 997 }
 998
 999 const MCSection *TargetLoweringObjectFileCOFF::getEHFrameSection() const {
1000   return getContext().getCOFFSection(".eh_frame",
1001                                      COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
1002                                      COFF::IMAGE_SCN_MEM_READ |
1003                                      COFF::IMAGE_SCN_MEM_WRITE,
1004                                      SectionKind::getDataRel());
1005 }
1006
1007
1008 static unsigned
1009 getCOFFSectionFlags(SectionKind K) {
1010   unsigned Flags = 0;
1011
1012   if (K.isMetadata())
1013     Flags |=
1014       COFF::IMAGE_SCN_MEM_DISCARDABLE;
1015   else if (K.isText())
1016     Flags |=
1017       COFF::IMAGE_SCN_MEM_EXECUTE |
1018       COFF::IMAGE_SCN_MEM_READ |
1019       COFF::IMAGE_SCN_CNT_CODE;
1020   else if (K.isBSS ())
1021     Flags |=
1022       COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
1023       COFF::IMAGE_SCN_MEM_READ |
1024       COFF::IMAGE_SCN_MEM_WRITE;
1025   else if (K.isReadOnly())
1026     Flags |=
1027       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
1028       COFF::IMAGE_SCN_MEM_READ;
1029   else if (K.isWriteable())
1030     Flags |=
1031       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
1032       COFF::IMAGE_SCN_MEM_READ |
1033       COFF::IMAGE_SCN_MEM_WRITE;
1034
1035   return Flags;
1036 }
1037
1038 const MCSection *TargetLoweringObjectFileCOFF::
1039 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
1040                          Mangler *Mang, const TargetMachine &TM) const {
1041   return getContext().getCOFFSection(GV->getSection(),
1042                                      getCOFFSectionFlags(Kind),
1043                                      Kind);
1044 }
1045
1046 static const char *getCOFFSectionPrefixForUniqueGlobal(SectionKind Kind) {
1047   if (Kind.isText())
1048     return ".text$";
1049   if (Kind.isBSS ())
1050     return ".bss$";
1051   if (Kind.isWriteable())
1052     return ".data$";
1053   return ".rdata$";
1054 }
1055
1056
1057 const MCSection *TargetLoweringObjectFileCOFF::
1058 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
1059                        Mangler *Mang, const TargetMachine &TM) const {
1060   assert(!Kind.isThreadLocal() && "Doesn't support TLS");
1061
1062   // If this global is linkonce/weak and the target handles this by emitting it
1063   // into a 'uniqued' section name, create and return the section now.
1064   if (GV->isWeakForLinker()) {
1065     const char *Prefix = getCOFFSectionPrefixForUniqueGlobal(Kind);
1066     SmallString<128> Name(Prefix, Prefix+strlen(Prefix));
1067     MCSymbol *Sym = Mang->getSymbol(GV);
1068     Name.append(Sym->getName().begin() + 1, Sym->getName().end());
1069
1070     unsigned Characteristics = getCOFFSectionFlags(Kind);
1071
1072     Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
1073
1074     return getContext().getCOFFSection(Name.str(), Characteristics,
1075                           COFF::IMAGE_COMDAT_SELECT_ANY, Kind);
1076   }
1077
1078   if (Kind.isText())
1079     return getTextSection();
1080
1081   return getDataSection();
1082 }
1083