lib/Target/TargetLoweringObjectFile.cpp

   1 //===-- llvm/Target/TargetLoweringObjectFile.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/Target/TargetLoweringObjectFile.h"
  16 #include "llvm/Constants.h"
  17 #include "llvm/DerivedTypes.h"
  18 #include "llvm/Function.h"
  19 #include "llvm/GlobalVariable.h"
  20 #include "llvm/MC/MCContext.h"
  21 #include "llvm/MC/MCExpr.h"
  22 #include "llvm/MC/MCSectionMachO.h"
  23 #include "llvm/MC/MCSectionELF.h"
  24 #include "llvm/Target/TargetData.h"
  25 #include "llvm/Target/TargetMachine.h"
  26 #include "llvm/Target/TargetOptions.h"
  27 #include "llvm/Support/Mangler.h"
  28 #include "llvm/ADT/SmallString.h"
  29 #include "llvm/ADT/StringExtras.h"
  30 using namespace llvm;
  31
  32 //===----------------------------------------------------------------------===//
  33 //                              Generic Code
  34 //===----------------------------------------------------------------------===//
  35
  36 TargetLoweringObjectFile::TargetLoweringObjectFile() : Ctx(0) {
  37   TextSection = 0;
  38   DataSection = 0;
  39   BSSSection = 0;
  40   ReadOnlySection = 0;
  41   StaticCtorSection = 0;
  42   StaticDtorSection = 0;
  43   LSDASection = 0;
  44   EHFrameSection = 0;
  45
  46   DwarfAbbrevSection = 0;
  47   DwarfInfoSection = 0;
  48   DwarfLineSection = 0;
  49   DwarfFrameSection = 0;
  50   DwarfPubNamesSection = 0;
  51   DwarfPubTypesSection = 0;
  52   DwarfDebugInlineSection = 0;
  53   DwarfStrSection = 0;
  54   DwarfLocSection = 0;
  55   DwarfARangesSection = 0;
  56   DwarfRangesSection = 0;
  57   DwarfMacroInfoSection = 0;
  58 }
  59
  60 TargetLoweringObjectFile::~TargetLoweringObjectFile() {
  61 }
  62
  63 static bool isSuitableForBSS(const GlobalVariable *GV) {
  64   Constant *C = GV->getInitializer();
  65
  66   // Must have zero initializer.
  67   if (!C->isNullValue())
  68     return false;
  69
  70   // Leave constant zeros in readonly constant sections, so they can be shared.
  71   if (GV->isConstant())
  72     return false;
  73
  74   // If the global has an explicit section specified, don't put it in BSS.
  75   if (!GV->getSection().empty())
  76     return false;
  77
  78   // If -nozero-initialized-in-bss is specified, don't ever use BSS.
  79   if (NoZerosInBSS)
  80     return false;
  81
  82   // Otherwise, put it in BSS!
  83   return true;
  84 }
  85
  86 /// IsNullTerminatedString - Return true if the specified constant (which is
  87 /// known to have a type that is an array of 1/2/4 byte elements) ends with a
  88 /// nul value and contains no other nuls in it.
  89 static bool IsNullTerminatedString(const Constant *C) {
  90   const ArrayType *ATy = cast<ArrayType>(C->getType());
  91
  92   // First check: is we have constant array of i8 terminated with zero
  93   if (const ConstantArray *CVA = dyn_cast<ConstantArray>(C)) {
  94     if (ATy->getNumElements() == 0) return false;
  95
  96     ConstantInt *Null =
  97       dyn_cast<ConstantInt>(CVA->getOperand(ATy->getNumElements()-1));
  98     if (Null == 0 || Null->getZExtValue() != 0)
  99       return false; // Not null terminated.
 100
 101     // Verify that the null doesn't occur anywhere else in the string.
 102     for (unsigned i = 0, e = ATy->getNumElements()-1; i != e; ++i)
 103       // Reject constantexpr elements etc.
 104       if (!isa<ConstantInt>(CVA->getOperand(i)) ||
 105           CVA->getOperand(i) == Null)
 106         return false;
 107     return true;
 108   }
 109
 110   // Another possibility: [1 x i8] zeroinitializer
 111   if (isa<ConstantAggregateZero>(C))
 112     return ATy->getNumElements() == 1;
 113
 114   return false;
 115 }
 116
 117 /// getKindForGlobal - This is a top-level target-independent classifier for
 118 /// a global variable.  Given an global variable and information from TM, it
 119 /// classifies the global in a variety of ways that make various target
 120 /// implementations simpler.  The target implementation is free to ignore this
 121 /// extra info of course.
 122 SectionKind TargetLoweringObjectFile::getKindForGlobal(const GlobalValue *GV,
 123                                                        const TargetMachine &TM){
 124   assert(!GV->isDeclaration() && !GV->hasAvailableExternallyLinkage() &&
 125          "Can only be used for global definitions");
 126
 127   Reloc::Model ReloModel = TM.getRelocationModel();
 128
 129   // Early exit - functions should be always in text sections.
 130   const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
 131   if (GVar == 0)
 132     return SectionKind::getText();
 133
 134   // Handle thread-local data first.
 135   if (GVar->isThreadLocal()) {
 136     if (isSuitableForBSS(GVar))
 137       return SectionKind::getThreadBSS();
 138     return SectionKind::getThreadData();
 139   }
 140
 141   // Variable can be easily put to BSS section.
 142   if (isSuitableForBSS(GVar))
 143     return SectionKind::getBSS();
 144
 145   Constant *C = GVar->getInitializer();
 146
 147   // If the global is marked constant, we can put it into a mergable section,
 148   // a mergable string section, or general .data if it contains relocations.
 149   if (GVar->isConstant()) {
 150     // If the initializer for the global contains something that requires a
 151     // relocation, then we may have to drop this into a wriable data section
 152     // even though it is marked const.
 153     switch (C->getRelocationInfo()) {
 154     default: llvm_unreachable("unknown relocation info kind");
 155     case Constant::NoRelocation:
 156       // If initializer is a null-terminated string, put it in a "cstring"
 157       // section of the right width.
 158       if (const ArrayType *ATy = dyn_cast<ArrayType>(C->getType())) {
 159         if (const IntegerType *ITy =
 160               dyn_cast<IntegerType>(ATy->getElementType())) {
 161           if ((ITy->getBitWidth() == 8 || ITy->getBitWidth() == 16 ||
 162                ITy->getBitWidth() == 32) &&
 163               IsNullTerminatedString(C)) {
 164             if (ITy->getBitWidth() == 8)
 165               return SectionKind::getMergeable1ByteCString();
 166             if (ITy->getBitWidth() == 16)
 167               return SectionKind::getMergeable2ByteCString();
 168
 169             assert(ITy->getBitWidth() == 32 && "Unknown width");
 170             return SectionKind::getMergeable4ByteCString();
 171           }
 172         }
 173       }
 174
 175       // Otherwise, just drop it into a mergable constant section.  If we have
 176       // a section for this size, use it, otherwise use the arbitrary sized
 177       // mergable section.
 178       switch (TM.getTargetData()->getTypeAllocSize(C->getType())) {
 179       case 4:  return SectionKind::getMergeableConst4();
 180       case 8:  return SectionKind::getMergeableConst8();
 181       case 16: return SectionKind::getMergeableConst16();
 182       default: return SectionKind::getMergeableConst();
 183       }
 184
 185     case Constant::LocalRelocation:
 186       // In static relocation model, the linker will resolve all addresses, so
 187       // the relocation entries will actually be constants by the time the app
 188       // starts up.  However, we can't put this into a mergable section, because
 189       // the linker doesn't take relocations into consideration when it tries to
 190       // merge entries in the section.
 191       if (ReloModel == Reloc::Static)
 192         return SectionKind::getReadOnly();
 193
 194       // Otherwise, the dynamic linker needs to fix it up, put it in the
 195       // writable data.rel.local section.
 196       return SectionKind::getReadOnlyWithRelLocal();
 197
 198     case Constant::GlobalRelocations:
 199       // In static relocation model, the linker will resolve all addresses, so
 200       // the relocation entries will actually be constants by the time the app
 201       // starts up.  However, we can't put this into a mergable section, because
 202       // the linker doesn't take relocations into consideration when it tries to
 203       // merge entries in the section.
 204       if (ReloModel == Reloc::Static)
 205         return SectionKind::getReadOnly();
 206
 207       // Otherwise, the dynamic linker needs to fix it up, put it in the
 208       // writable data.rel section.
 209       return SectionKind::getReadOnlyWithRel();
 210     }
 211   }
 212
 213   // Okay, this isn't a constant.  If the initializer for the global is going
 214   // to require a runtime relocation by the dynamic linker, put it into a more
 215   // specific section to improve startup time of the app.  This coalesces these
 216   // globals together onto fewer pages, improving the locality of the dynamic
 217   // linker.
 218   if (ReloModel == Reloc::Static)
 219     return SectionKind::getDataNoRel();
 220
 221   switch (C->getRelocationInfo()) {
 222   default: llvm_unreachable("unknown relocation info kind");
 223   case Constant::NoRelocation:
 224     return SectionKind::getDataNoRel();
 225   case Constant::LocalRelocation:
 226     return SectionKind::getDataRelLocal();
 227   case Constant::GlobalRelocations:
 228     return SectionKind::getDataRel();
 229   }
 230 }
 231
 232 /// SectionForGlobal - This method computes the appropriate section to emit
 233 /// the specified global variable or function definition.  This should not
 234 /// be passed external (or available externally) globals.
 235 const MCSection *TargetLoweringObjectFile::
 236 SectionForGlobal(const GlobalValue *GV, SectionKind Kind, Mangler *Mang,
 237                  const TargetMachine &TM) const {
 238   // Select section name.
 239   if (GV->hasSection())
 240     return getExplicitSectionGlobal(GV, Kind, Mang, TM);
 241
 242
 243   // Use default section depending on the 'type' of global
 244   return SelectSectionForGlobal(GV, Kind, Mang, TM);
 245 }
 246
 247
 248 // Lame default implementation. Calculate the section name for global.
 249 const MCSection *
 250 TargetLoweringObjectFile::SelectSectionForGlobal(const GlobalValue *GV,
 251                                                  SectionKind Kind,
 252                                                  Mangler *Mang,
 253                                                  const TargetMachine &TM) const{
 254   assert(!Kind.isThreadLocal() && "Doesn't support TLS");
 255
 256   if (Kind.isText())
 257     return getTextSection();
 258
 259   if (Kind.isBSS() && BSSSection != 0)
 260     return BSSSection;
 261
 262   if (Kind.isReadOnly() && ReadOnlySection != 0)
 263     return ReadOnlySection;
 264
 265   return getDataSection();
 266 }
 267
 268 /// getSectionForConstant - Given a mergable constant with the
 269 /// specified size and relocation information, return a section that it
 270 /// should be placed in.
 271 const MCSection *
 272 TargetLoweringObjectFile::getSectionForConstant(SectionKind Kind) const {
 273   if (Kind.isReadOnly() && ReadOnlySection != 0)
 274     return ReadOnlySection;
 275
 276   return DataSection;
 277 }
 278
 279 /// getSymbolForDwarfGlobalReference - Return an MCExpr to use for a
 280 /// pc-relative reference to the specified global variable from exception
 281 /// handling information.  In addition to the symbol, this returns
 282 /// by-reference:
 283 ///
 284 /// IsIndirect - True if the returned symbol is actually a stub that contains
 285 ///    the address of the symbol, false if the symbol is the global itself.
 286 ///
 287 /// IsPCRel - True if the symbol reference is already pc-relative, false if
 288 ///    the caller needs to subtract off the address of the reference from the
 289 ///    symbol.
 290 ///
 291 const MCExpr *TargetLoweringObjectFile::
 292 getSymbolForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
 293                                  MachineModuleInfo *MMI,
 294                                  bool &IsIndirect, bool &IsPCRel) const {
 295   // The generic implementation of this just returns a direct reference to the
 296   // symbol.
 297   IsIndirect = false;
 298   IsPCRel    = false;
 299
 300   SmallString<128> Name;
 301   Mang->getNameWithPrefix(Name, GV, false);
 302   return MCSymbolRefExpr::Create(Name.str(), getContext());
 303 }
 304
 305
 306 //===----------------------------------------------------------------------===//
 307 //                                  ELF
 308 //===----------------------------------------------------------------------===//
 309 typedef StringMap<const MCSectionELF*> ELFUniqueMapTy;
 310
 311 TargetLoweringObjectFileELF::~TargetLoweringObjectFileELF() {
 312   // If we have the section uniquing map, free it.
 313   delete (ELFUniqueMapTy*)UniquingMap;
 314 }
 315
 316 const MCSection *TargetLoweringObjectFileELF::
 317 getELFSection(StringRef Section, unsigned Type, unsigned Flags,
 318               SectionKind Kind, bool IsExplicit) const {
 319   if (UniquingMap == 0)
 320     UniquingMap = new ELFUniqueMapTy();
 321   ELFUniqueMapTy &Map = *(ELFUniqueMapTy*)UniquingMap;
 322
 323   // Do the lookup, if we have a hit, return it.
 324   const MCSectionELF *&Entry = Map[Section];
 325   if (Entry) return Entry;
 326
 327   return Entry = MCSectionELF::Create(Section, Type, Flags, Kind, IsExplicit,
 328                                       getContext());
 329 }
 330
 331 void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx,
 332                                              const TargetMachine &TM) {
 333   if (UniquingMap != 0)
 334     ((ELFUniqueMapTy*)UniquingMap)->clear();
 335   TargetLoweringObjectFile::Initialize(Ctx, TM);
 336
 337   BSSSection =
 338     getELFSection(".bss", MCSectionELF::SHT_NOBITS,
 339                   MCSectionELF::SHF_WRITE | MCSectionELF::SHF_ALLOC,
 340                   SectionKind::getBSS());
 341
 342   TextSection =
 343     getELFSection(".text", MCSectionELF::SHT_PROGBITS,
 344                   MCSectionELF::SHF_EXECINSTR | MCSectionELF::SHF_ALLOC,
 345                   SectionKind::getText());
 346
 347   DataSection =
 348     getELFSection(".data", MCSectionELF::SHT_PROGBITS,
 349                   MCSectionELF::SHF_WRITE | MCSectionELF::SHF_ALLOC,
 350                   SectionKind::getDataRel());
 351
 352   ReadOnlySection =
 353     getELFSection(".rodata", MCSectionELF::SHT_PROGBITS,
 354                   MCSectionELF::SHF_ALLOC,
 355                   SectionKind::getReadOnly());
 356
 357   TLSDataSection =
 358     getELFSection(".tdata", MCSectionELF::SHT_PROGBITS,
 359                   MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_TLS |
 360                   MCSectionELF::SHF_WRITE, SectionKind::getThreadData());
 361
 362   TLSBSSSection =
 363     getELFSection(".tbss", MCSectionELF::SHT_NOBITS,
 364                   MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_TLS |
 365                   MCSectionELF::SHF_WRITE, SectionKind::getThreadBSS());
 366
 367   DataRelSection =
 368     getELFSection(".data.rel", MCSectionELF::SHT_PROGBITS,
 369                   MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE,
 370                   SectionKind::getDataRel());
 371
 372   DataRelLocalSection =
 373     getELFSection(".data.rel.local", MCSectionELF::SHT_PROGBITS,
 374                   MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE,
 375                   SectionKind::getDataRelLocal());
 376
 377   DataRelROSection =
 378     getELFSection(".data.rel.ro", MCSectionELF::SHT_PROGBITS,
 379                   MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE,
 380                   SectionKind::getReadOnlyWithRel());
 381
 382   DataRelROLocalSection =
 383     getELFSection(".data.rel.ro.local", MCSectionELF::SHT_PROGBITS,
 384                   MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE,
 385                   SectionKind::getReadOnlyWithRelLocal());
 386
 387   MergeableConst4Section =
 388     getELFSection(".rodata.cst4", MCSectionELF::SHT_PROGBITS,
 389                   MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_MERGE,
 390                   SectionKind::getMergeableConst4());
 391
 392   MergeableConst8Section =
 393     getELFSection(".rodata.cst8", MCSectionELF::SHT_PROGBITS,
 394                   MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_MERGE,
 395                   SectionKind::getMergeableConst8());
 396
 397   MergeableConst16Section =
 398     getELFSection(".rodata.cst16", MCSectionELF::SHT_PROGBITS,
 399                   MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_MERGE,
 400                   SectionKind::getMergeableConst16());
 401
 402   StaticCtorSection =
 403     getELFSection(".ctors", MCSectionELF::SHT_PROGBITS,
 404                   MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE,
 405                   SectionKind::getDataRel());
 406
 407   StaticDtorSection =
 408     getELFSection(".dtors", MCSectionELF::SHT_PROGBITS,
 409                   MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE,
 410                   SectionKind::getDataRel());
 411
 412   // Exception Handling Sections.
 413
 414   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
 415   // it contains relocatable pointers.  In PIC mode, this is probably a big
 416   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
 417   // adjusted or this should be a data section.
 418   LSDASection =
 419     getELFSection(".gcc_except_table", MCSectionELF::SHT_PROGBITS,
 420                   MCSectionELF::SHF_ALLOC, SectionKind::getReadOnly());
 421   EHFrameSection =
 422     getELFSection(".eh_frame", MCSectionELF::SHT_PROGBITS,
 423                   MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE,
 424                   SectionKind::getDataRel());
 425
 426   // Debug Info Sections.
 427   DwarfAbbrevSection =
 428     getELFSection(".debug_abbrev", MCSectionELF::SHT_PROGBITS, 0,
 429                   SectionKind::getMetadata());
 430   DwarfInfoSection =
 431     getELFSection(".debug_info", MCSectionELF::SHT_PROGBITS, 0,
 432                   SectionKind::getMetadata());
 433   DwarfLineSection =
 434     getELFSection(".debug_line", MCSectionELF::SHT_PROGBITS, 0,
 435                   SectionKind::getMetadata());
 436   DwarfFrameSection =
 437     getELFSection(".debug_frame", MCSectionELF::SHT_PROGBITS, 0,
 438                   SectionKind::getMetadata());
 439   DwarfPubNamesSection =
 440     getELFSection(".debug_pubnames", MCSectionELF::SHT_PROGBITS, 0,
 441                   SectionKind::getMetadata());
 442   DwarfPubTypesSection =
 443     getELFSection(".debug_pubtypes", MCSectionELF::SHT_PROGBITS, 0,
 444                   SectionKind::getMetadata());
 445   DwarfStrSection =
 446     getELFSection(".debug_str", MCSectionELF::SHT_PROGBITS, 0,
 447                   SectionKind::getMetadata());
 448   DwarfLocSection =
 449     getELFSection(".debug_loc", MCSectionELF::SHT_PROGBITS, 0,
 450                   SectionKind::getMetadata());
 451   DwarfARangesSection =
 452     getELFSection(".debug_aranges", MCSectionELF::SHT_PROGBITS, 0,
 453                   SectionKind::getMetadata());
 454   DwarfRangesSection =
 455     getELFSection(".debug_ranges", MCSectionELF::SHT_PROGBITS, 0,
 456                   SectionKind::getMetadata());
 457   DwarfMacroInfoSection =
 458     getELFSection(".debug_macinfo", MCSectionELF::SHT_PROGBITS, 0,
 459                   SectionKind::getMetadata());
 460 }
 461
 462
 463 static SectionKind
 464 getELFKindForNamedSection(const char *Name, SectionKind K) {
 465   if (Name[0] != '.') return K;
 466
 467   // Some lame default implementation based on some magic section names.
 468   if (strcmp(Name, ".bss") == 0 ||
 469       strncmp(Name, ".bss.", 5) == 0 ||
 470       strncmp(Name, ".gnu.linkonce.b.", 16) == 0 ||
 471       strncmp(Name, ".llvm.linkonce.b.", 17) == 0 ||
 472       strcmp(Name, ".sbss") == 0 ||
 473       strncmp(Name, ".sbss.", 6) == 0 ||
 474       strncmp(Name, ".gnu.linkonce.sb.", 17) == 0 ||
 475       strncmp(Name, ".llvm.linkonce.sb.", 18) == 0)
 476     return SectionKind::getBSS();
 477
 478   if (strcmp(Name, ".tdata") == 0 ||
 479       strncmp(Name, ".tdata.", 7) == 0 ||
 480       strncmp(Name, ".gnu.linkonce.td.", 17) == 0 ||
 481       strncmp(Name, ".llvm.linkonce.td.", 18) == 0)
 482     return SectionKind::getThreadData();
 483
 484   if (strcmp(Name, ".tbss") == 0 ||
 485       strncmp(Name, ".tbss.", 6) == 0 ||
 486       strncmp(Name, ".gnu.linkonce.tb.", 17) == 0 ||
 487       strncmp(Name, ".llvm.linkonce.tb.", 18) == 0)
 488     return SectionKind::getThreadBSS();
 489
 490   return K;
 491 }
 492
 493
 494 static unsigned
 495 getELFSectionType(const char *Name, SectionKind K) {
 496
 497   if (strcmp(Name, ".init_array") == 0)
 498     return MCSectionELF::SHT_INIT_ARRAY;
 499
 500   if (strcmp(Name, ".fini_array") == 0)
 501     return MCSectionELF::SHT_FINI_ARRAY;
 502
 503   if (strcmp(Name, ".preinit_array") == 0)
 504     return MCSectionELF::SHT_PREINIT_ARRAY;
 505
 506   if (K.isBSS() || K.isThreadBSS())
 507     return MCSectionELF::SHT_NOBITS;
 508
 509   return MCSectionELF::SHT_PROGBITS;
 510 }
 511
 512
 513 static unsigned
 514 getELFSectionFlags(SectionKind K) {
 515   unsigned Flags = 0;
 516
 517   if (!K.isMetadata())
 518     Flags |= MCSectionELF::SHF_ALLOC;
 519
 520   if (K.isText())
 521     Flags |= MCSectionELF::SHF_EXECINSTR;
 522
 523   if (K.isWriteable())
 524     Flags |= MCSectionELF::SHF_WRITE;
 525
 526   if (K.isThreadLocal())
 527     Flags |= MCSectionELF::SHF_TLS;
 528
 529   // K.isMergeableConst() is left out to honour PR4650
 530   if (K.isMergeableCString() || K.isMergeableConst4() ||
 531       K.isMergeableConst8() || K.isMergeableConst16())
 532     Flags |= MCSectionELF::SHF_MERGE;
 533
 534   if (K.isMergeableCString())
 535     Flags |= MCSectionELF::SHF_STRINGS;
 536
 537   return Flags;
 538 }
 539
 540
 541 const MCSection *TargetLoweringObjectFileELF::
 542 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
 543                          Mangler *Mang, const TargetMachine &TM) const {
 544   const char *SectionName = GV->getSection().c_str();
 545
 546   // Infer section flags from the section name if we can.
 547   Kind = getELFKindForNamedSection(SectionName, Kind);
 548
 549   return getELFSection(SectionName,
 550                        getELFSectionType(SectionName, Kind),
 551                        getELFSectionFlags(Kind), Kind, true);
 552 }
 553
 554 static const char *getSectionPrefixForUniqueGlobal(SectionKind Kind) {
 555   if (Kind.isText())                 return ".gnu.linkonce.t.";
 556   if (Kind.isReadOnly())             return ".gnu.linkonce.r.";
 557
 558   if (Kind.isThreadData())           return ".gnu.linkonce.td.";
 559   if (Kind.isThreadBSS())            return ".gnu.linkonce.tb.";
 560
 561   if (Kind.isBSS())                  return ".gnu.linkonce.b.";
 562   if (Kind.isDataNoRel())            return ".gnu.linkonce.d.";
 563   if (Kind.isDataRelLocal())         return ".gnu.linkonce.d.rel.local.";
 564   if (Kind.isDataRel())              return ".gnu.linkonce.d.rel.";
 565   if (Kind.isReadOnlyWithRelLocal()) return ".gnu.linkonce.d.rel.ro.local.";
 566
 567   assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
 568   return ".gnu.linkonce.d.rel.ro.";
 569 }
 570
 571 const MCSection *TargetLoweringObjectFileELF::
 572 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
 573                        Mangler *Mang, const TargetMachine &TM) const {
 574
 575   // If this global is linkonce/weak and the target handles this by emitting it
 576   // into a 'uniqued' section name, create and return the section now.
 577   if (GV->isWeakForLinker()) {
 578     const char *Prefix = getSectionPrefixForUniqueGlobal(Kind);
 579     std::string Name = Mang->makeNameProper(GV->getNameStr());
 580
 581     return getELFSection((Prefix+Name).c_str(),
 582                          getELFSectionType((Prefix+Name).c_str(), Kind),
 583                          getELFSectionFlags(Kind),
 584                          Kind);
 585   }
 586
 587   if (Kind.isText()) return TextSection;
 588
 589   if (Kind.isMergeable1ByteCString() ||
 590       Kind.isMergeable2ByteCString() ||
 591       Kind.isMergeable4ByteCString()) {
 592
 593     // We also need alignment here.
 594     // FIXME: this is getting the alignment of the character, not the
 595     // alignment of the global!
 596     unsigned Align =
 597       TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV));
 598
 599     const char *SizeSpec = ".rodata.str1.";
 600     if (Kind.isMergeable2ByteCString())
 601       SizeSpec = ".rodata.str2.";
 602     else if (Kind.isMergeable4ByteCString())
 603       SizeSpec = ".rodata.str4.";
 604     else
 605       assert(Kind.isMergeable1ByteCString() && "unknown string width");
 606
 607
 608     std::string Name = SizeSpec + utostr(Align);
 609     return getELFSection(Name.c_str(), MCSectionELF::SHT_PROGBITS,
 610                          MCSectionELF::SHF_ALLOC |
 611                          MCSectionELF::SHF_MERGE |
 612                          MCSectionELF::SHF_STRINGS,
 613                          Kind);
 614   }
 615
 616   if (Kind.isMergeableConst()) {
 617     if (Kind.isMergeableConst4() && MergeableConst4Section)
 618       return MergeableConst4Section;
 619     if (Kind.isMergeableConst8() && MergeableConst8Section)
 620       return MergeableConst8Section;
 621     if (Kind.isMergeableConst16() && MergeableConst16Section)
 622       return MergeableConst16Section;
 623     return ReadOnlySection;  // .const
 624   }
 625
 626   if (Kind.isReadOnly())             return ReadOnlySection;
 627
 628   if (Kind.isThreadData())           return TLSDataSection;
 629   if (Kind.isThreadBSS())            return TLSBSSSection;
 630
 631   if (Kind.isBSS())                  return BSSSection;
 632
 633   if (Kind.isDataNoRel())            return DataSection;
 634   if (Kind.isDataRelLocal())         return DataRelLocalSection;
 635   if (Kind.isDataRel())              return DataRelSection;
 636   if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
 637
 638   assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
 639   return DataRelROSection;
 640 }
 641
 642 /// getSectionForConstant - Given a mergeable constant with the
 643 /// specified size and relocation information, return a section that it
 644 /// should be placed in.
 645 const MCSection *TargetLoweringObjectFileELF::
 646 getSectionForConstant(SectionKind Kind) const {
 647   if (Kind.isMergeableConst4() && MergeableConst4Section)
 648     return MergeableConst4Section;
 649   if (Kind.isMergeableConst8() && MergeableConst8Section)
 650     return MergeableConst8Section;
 651   if (Kind.isMergeableConst16() && MergeableConst16Section)
 652     return MergeableConst16Section;
 653   if (Kind.isReadOnly())
 654     return ReadOnlySection;
 655
 656   if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
 657   assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
 658   return DataRelROSection;
 659 }
 660
 661 //===----------------------------------------------------------------------===//
 662 //                                 MachO
 663 //===----------------------------------------------------------------------===//
 664
 665 typedef StringMap<const MCSectionMachO*> MachOUniqueMapTy;
 666
 667 TargetLoweringObjectFileMachO::~TargetLoweringObjectFileMachO() {
 668   // If we have the MachO uniquing map, free it.
 669   delete (MachOUniqueMapTy*)UniquingMap;
 670 }
 671
 672
 673 const MCSectionMachO *TargetLoweringObjectFileMachO::
 674 getMachOSection(const StringRef &Segment, const StringRef &Section,
 675                 unsigned TypeAndAttributes,
 676                 unsigned Reserved2, SectionKind Kind) const {
 677   // We unique sections by their segment/section pair.  The returned section
 678   // may not have the same flags as the requested section, if so this should be
 679   // diagnosed by the client as an error.
 680
 681   // Create the map if it doesn't already exist.
 682   if (UniquingMap == 0)
 683     UniquingMap = new MachOUniqueMapTy();
 684   MachOUniqueMapTy &Map = *(MachOUniqueMapTy*)UniquingMap;
 685
 686   // Form the name to look up.
 687   SmallString<64> Name;
 688   Name += Segment;
 689   Name.push_back(',');
 690   Name += Section;
 691
 692   // Do the lookup, if we have a hit, return it.
 693   const MCSectionMachO *&Entry = Map[Name.str()];
 694   if (Entry) return Entry;
 695
 696   // Otherwise, return a new section.
 697   return Entry = MCSectionMachO::Create(Segment, Section, TypeAndAttributes,
 698                                         Reserved2, Kind, getContext());
 699 }
 700
 701
 702 void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx,
 703                                                const TargetMachine &TM) {
 704   if (UniquingMap != 0)
 705     ((MachOUniqueMapTy*)UniquingMap)->clear();
 706   TargetLoweringObjectFile::Initialize(Ctx, TM);
 707
 708   TextSection // .text
 709     = getMachOSection("__TEXT", "__text",
 710                       MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
 711                       SectionKind::getText());
 712   DataSection // .data
 713     = getMachOSection("__DATA", "__data", 0, SectionKind::getDataRel());
 714
 715   CStringSection // .cstring
 716     = getMachOSection("__TEXT", "__cstring", MCSectionMachO::S_CSTRING_LITERALS,
 717                       SectionKind::getMergeable1ByteCString());
 718   UStringSection
 719     = getMachOSection("__TEXT","__ustring", 0,
 720                       SectionKind::getMergeable2ByteCString());
 721   FourByteConstantSection // .literal4
 722     = getMachOSection("__TEXT", "__literal4", MCSectionMachO::S_4BYTE_LITERALS,
 723                       SectionKind::getMergeableConst4());
 724   EightByteConstantSection // .literal8
 725     = getMachOSection("__TEXT", "__literal8", MCSectionMachO::S_8BYTE_LITERALS,
 726                       SectionKind::getMergeableConst8());
 727
 728   // ld_classic doesn't support .literal16 in 32-bit mode, and ld64 falls back
 729   // to using it in -static mode.
 730   SixteenByteConstantSection = 0;
 731   if (TM.getRelocationModel() != Reloc::Static &&
 732       TM.getTargetData()->getPointerSize() == 32)
 733     SixteenByteConstantSection =   // .literal16
 734       getMachOSection("__TEXT", "__literal16",MCSectionMachO::S_16BYTE_LITERALS,
 735                       SectionKind::getMergeableConst16());
 736
 737   ReadOnlySection  // .const
 738     = getMachOSection("__TEXT", "__const", 0, SectionKind::getReadOnly());
 739
 740   TextCoalSection
 741     = getMachOSection("__TEXT", "__textcoal_nt",
 742                       MCSectionMachO::S_COALESCED |
 743                       MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
 744                       SectionKind::getText());
 745   ConstTextCoalSection
 746     = getMachOSection("__TEXT", "__const_coal", MCSectionMachO::S_COALESCED,
 747                       SectionKind::getText());
 748   ConstDataCoalSection
 749     = getMachOSection("__DATA","__const_coal", MCSectionMachO::S_COALESCED,
 750                       SectionKind::getText());
 751   ConstDataSection  // .const_data
 752     = getMachOSection("__DATA", "__const", 0,
 753                       SectionKind::getReadOnlyWithRel());
 754   DataCoalSection
 755     = getMachOSection("__DATA","__datacoal_nt", MCSectionMachO::S_COALESCED,
 756                       SectionKind::getDataRel());
 757
 758
 759   LazySymbolPointerSection
 760     = getMachOSection("__DATA", "__la_symbol_ptr",
 761                       MCSectionMachO::S_LAZY_SYMBOL_POINTERS,
 762                       SectionKind::getMetadata());
 763   NonLazySymbolPointerSection
 764     = getMachOSection("__DATA", "__nl_symbol_ptr",
 765                       MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS,
 766                       SectionKind::getMetadata());
 767
 768   if (TM.getRelocationModel() == Reloc::Static) {
 769     StaticCtorSection
 770       = getMachOSection("__TEXT", "__constructor", 0,SectionKind::getDataRel());
 771     StaticDtorSection
 772       = getMachOSection("__TEXT", "__destructor", 0, SectionKind::getDataRel());
 773   } else {
 774     StaticCtorSection
 775       = getMachOSection("__DATA", "__mod_init_func",
 776                         MCSectionMachO::S_MOD_INIT_FUNC_POINTERS,
 777                         SectionKind::getDataRel());
 778     StaticDtorSection
 779       = getMachOSection("__DATA", "__mod_term_func",
 780                         MCSectionMachO::S_MOD_TERM_FUNC_POINTERS,
 781                         SectionKind::getDataRel());
 782   }
 783
 784   // Exception Handling.
 785   LSDASection = getMachOSection("__DATA", "__gcc_except_tab", 0,
 786                                 SectionKind::getDataRel());
 787   EHFrameSection =
 788     getMachOSection("__TEXT", "__eh_frame",
 789                     MCSectionMachO::S_COALESCED |
 790                     MCSectionMachO::S_ATTR_NO_TOC |
 791                     MCSectionMachO::S_ATTR_STRIP_STATIC_SYMS |
 792                     MCSectionMachO::S_ATTR_LIVE_SUPPORT,
 793                     SectionKind::getReadOnly());
 794
 795   // Debug Information.
 796   DwarfAbbrevSection =
 797     getMachOSection("__DWARF", "__debug_abbrev", MCSectionMachO::S_ATTR_DEBUG,
 798                     SectionKind::getMetadata());
 799   DwarfInfoSection =
 800     getMachOSection("__DWARF", "__debug_info", MCSectionMachO::S_ATTR_DEBUG,
 801                     SectionKind::getMetadata());
 802   DwarfLineSection =
 803     getMachOSection("__DWARF", "__debug_line", MCSectionMachO::S_ATTR_DEBUG,
 804                     SectionKind::getMetadata());
 805   DwarfFrameSection =
 806     getMachOSection("__DWARF", "__debug_frame", MCSectionMachO::S_ATTR_DEBUG,
 807                     SectionKind::getMetadata());
 808   DwarfPubNamesSection =
 809     getMachOSection("__DWARF", "__debug_pubnames", MCSectionMachO::S_ATTR_DEBUG,
 810                     SectionKind::getMetadata());
 811   DwarfPubTypesSection =
 812     getMachOSection("__DWARF", "__debug_pubtypes", MCSectionMachO::S_ATTR_DEBUG,
 813                     SectionKind::getMetadata());
 814   DwarfStrSection =
 815     getMachOSection("__DWARF", "__debug_str", MCSectionMachO::S_ATTR_DEBUG,
 816                     SectionKind::getMetadata());
 817   DwarfLocSection =
 818     getMachOSection("__DWARF", "__debug_loc", MCSectionMachO::S_ATTR_DEBUG,
 819                     SectionKind::getMetadata());
 820   DwarfARangesSection =
 821     getMachOSection("__DWARF", "__debug_aranges", MCSectionMachO::S_ATTR_DEBUG,
 822                     SectionKind::getMetadata());
 823   DwarfRangesSection =
 824     getMachOSection("__DWARF", "__debug_ranges", MCSectionMachO::S_ATTR_DEBUG,
 825                     SectionKind::getMetadata());
 826   DwarfMacroInfoSection =
 827     getMachOSection("__DWARF", "__debug_macinfo", MCSectionMachO::S_ATTR_DEBUG,
 828                     SectionKind::getMetadata());
 829   DwarfDebugInlineSection =
 830     getMachOSection("__DWARF", "__debug_inlined", MCSectionMachO::S_ATTR_DEBUG,
 831                     SectionKind::getMetadata());
 832 }
 833
 834 const MCSection *TargetLoweringObjectFileMachO::
 835 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
 836                          Mangler *Mang, const TargetMachine &TM) const {
 837   // Parse the section specifier and create it if valid.
 838   StringRef Segment, Section;
 839   unsigned TAA, StubSize;
 840   std::string ErrorCode =
 841     MCSectionMachO::ParseSectionSpecifier(GV->getSection(), Segment, Section,
 842                                           TAA, StubSize);
 843   if (!ErrorCode.empty()) {
 844     // If invalid, report the error with llvm_report_error.
 845     llvm_report_error("Global variable '" + GV->getNameStr() +
 846                       "' has an invalid section specifier '" + GV->getSection()+
 847                       "': " + ErrorCode + ".");
 848     // Fall back to dropping it into the data section.
 849     return DataSection;
 850   }
 851
 852   // Get the section.
 853   const MCSectionMachO *S =
 854     getMachOSection(Segment, Section, TAA, StubSize, Kind);
 855
 856   // Okay, now that we got the section, verify that the TAA & StubSize agree.
 857   // If the user declared multiple globals with different section flags, we need
 858   // to reject it here.
 859   if (S->getTypeAndAttributes() != TAA || S->getStubSize() != StubSize) {
 860     // If invalid, report the error with llvm_report_error.
 861     llvm_report_error("Global variable '" + GV->getNameStr() +
 862                       "' section type or attributes does not match previous"
 863                       " section specifier");
 864   }
 865
 866   return S;
 867 }
 868
 869 const MCSection *TargetLoweringObjectFileMachO::
 870 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
 871                        Mangler *Mang, const TargetMachine &TM) const {
 872   assert(!Kind.isThreadLocal() && "Darwin doesn't support TLS");
 873
 874   if (Kind.isText())
 875     return GV->isWeakForLinker() ? TextCoalSection : TextSection;
 876
 877   // If this is weak/linkonce, put this in a coalescable section, either in text
 878   // or data depending on if it is writable.
 879   if (GV->isWeakForLinker()) {
 880     if (Kind.isReadOnly())
 881       return ConstTextCoalSection;
 882     return DataCoalSection;
 883   }
 884
 885   // FIXME: Alignment check should be handled by section classifier.
 886   if (Kind.isMergeable1ByteCString() ||
 887       Kind.isMergeable2ByteCString()) {
 888     if (TM.getTargetData()->getPreferredAlignment(
 889                                               cast<GlobalVariable>(GV)) < 32) {
 890       if (Kind.isMergeable1ByteCString())
 891         return CStringSection;
 892       assert(Kind.isMergeable2ByteCString());
 893       return UStringSection;
 894     }
 895   }
 896
 897   if (Kind.isMergeableConst()) {
 898     if (Kind.isMergeableConst4())
 899       return FourByteConstantSection;
 900     if (Kind.isMergeableConst8())
 901       return EightByteConstantSection;
 902     if (Kind.isMergeableConst16() && SixteenByteConstantSection)
 903       return SixteenByteConstantSection;
 904   }
 905
 906   // Otherwise, if it is readonly, but not something we can specially optimize,
 907   // just drop it in .const.
 908   if (Kind.isReadOnly())
 909     return ReadOnlySection;
 910
 911   // If this is marked const, put it into a const section.  But if the dynamic
 912   // linker needs to write to it, put it in the data segment.
 913   if (Kind.isReadOnlyWithRel())
 914     return ConstDataSection;
 915
 916   // Otherwise, just drop the variable in the normal data section.
 917   return DataSection;
 918 }
 919
 920 const MCSection *
 921 TargetLoweringObjectFileMachO::getSectionForConstant(SectionKind Kind) const {
 922   // If this constant requires a relocation, we have to put it in the data
 923   // segment, not in the text segment.
 924   if (Kind.isDataRel())
 925     return ConstDataSection;
 926
 927   if (Kind.isMergeableConst4())
 928     return FourByteConstantSection;
 929   if (Kind.isMergeableConst8())
 930     return EightByteConstantSection;
 931   if (Kind.isMergeableConst16() && SixteenByteConstantSection)
 932     return SixteenByteConstantSection;
 933   return ReadOnlySection;  // .const
 934 }
 935
 936 /// shouldEmitUsedDirectiveFor - This hook allows targets to selectively decide
 937 /// not to emit the UsedDirective for some symbols in llvm.used.
 938 // FIXME: REMOVE this (rdar://7071300)
 939 bool TargetLoweringObjectFileMachO::
 940 shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler *Mang) const {
 941   /// On Darwin, internally linked data beginning with "L" or "l" does not have
 942   /// the directive emitted (this occurs in ObjC metadata).
 943   if (!GV) return false;
 944
 945   // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix.
 946   if (GV->hasLocalLinkage() && !isa<Function>(GV)) {
 947     // FIXME: ObjC metadata is currently emitted as internal symbols that have
 948     // \1L and \0l prefixes on them.  Fix them to be Private/LinkerPrivate and
 949     // this horrible hack can go away.
 950     const std::string &Name = Mang->getMangledName(GV);
 951     if (Name[0] == 'L' || Name[0] == 'l')
 952       return false;
 953   }
 954
 955   return true;
 956 }
 957
 958 const MCExpr *TargetLoweringObjectFileMachO::
 959 getSymbolForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
 960                                  MachineModuleInfo *MMI,
 961                                  bool &IsIndirect, bool &IsPCRel) const {
 962   // The mach-o version of this method defaults to returning a stub reference.
 963   IsIndirect = true;
 964   IsPCRel    = false;
 965
 966   SmallString<128> Name;
 967   Mang->getNameWithPrefix(Name, GV, true);
 968   Name += "$non_lazy_ptr";
 969   return MCSymbolRefExpr::Create(Name.str(), getContext());
 970 }
 971
 972
 973 //===----------------------------------------------------------------------===//
 974 //                                  COFF
 975 //===----------------------------------------------------------------------===//
 976
 977 typedef StringMap<const MCSectionCOFF*> COFFUniqueMapTy;
 978
 979 TargetLoweringObjectFileCOFF::~TargetLoweringObjectFileCOFF() {
 980   delete (COFFUniqueMapTy*)UniquingMap;
 981 }
 982
 983
 984 const MCSection *TargetLoweringObjectFileCOFF::
 985 getCOFFSection(const char *Name, bool isDirective, SectionKind Kind) const {
 986   // Create the map if it doesn't already exist.
 987   if (UniquingMap == 0)
 988     UniquingMap = new MachOUniqueMapTy();
 989   COFFUniqueMapTy &Map = *(COFFUniqueMapTy*)UniquingMap;
 990
 991   // Do the lookup, if we have a hit, return it.
 992   const MCSectionCOFF *&Entry = Map[Name];
 993   if (Entry) return Entry;
 994
 995   return Entry = MCSectionCOFF::Create(Name, isDirective, Kind, getContext());
 996 }
 997
 998 void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx,
 999                                               const TargetMachine &TM) {
1000   if (UniquingMap != 0)
1001     ((COFFUniqueMapTy*)UniquingMap)->clear();
1002   TargetLoweringObjectFile::Initialize(Ctx, TM);
1003   TextSection = getCOFFSection("\t.text", true, SectionKind::getText());
1004   DataSection = getCOFFSection("\t.data", true, SectionKind::getDataRel());
1005   StaticCtorSection =
1006     getCOFFSection(".ctors", false, SectionKind::getDataRel());
1007   StaticDtorSection =
1008     getCOFFSection(".dtors", false, SectionKind::getDataRel());
1009
1010   // FIXME: We're emitting LSDA info into a readonly section on COFF, even
1011   // though it contains relocatable pointers.  In PIC mode, this is probably a
1012   // big runtime hit for C++ apps.  Either the contents of the LSDA need to be
1013   // adjusted or this should be a data section.
1014   LSDASection =
1015     getCOFFSection(".gcc_except_table", false, SectionKind::getReadOnly());
1016   EHFrameSection =
1017     getCOFFSection(".eh_frame", false, SectionKind::getDataRel());
1018
1019   // Debug info.
1020   // FIXME: Don't use 'directive' mode here.
1021   DwarfAbbrevSection =
1022     getCOFFSection("\t.section\t.debug_abbrev,\"dr\"",
1023                    true, SectionKind::getMetadata());
1024   DwarfInfoSection =
1025     getCOFFSection("\t.section\t.debug_info,\"dr\"",
1026                    true, SectionKind::getMetadata());
1027   DwarfLineSection =
1028     getCOFFSection("\t.section\t.debug_line,\"dr\"",
1029                    true, SectionKind::getMetadata());
1030   DwarfFrameSection =
1031     getCOFFSection("\t.section\t.debug_frame,\"dr\"",
1032                    true, SectionKind::getMetadata());
1033   DwarfPubNamesSection =
1034     getCOFFSection("\t.section\t.debug_pubnames,\"dr\"",
1035                    true, SectionKind::getMetadata());
1036   DwarfPubTypesSection =
1037     getCOFFSection("\t.section\t.debug_pubtypes,\"dr\"",
1038                    true, SectionKind::getMetadata());
1039   DwarfStrSection =
1040     getCOFFSection("\t.section\t.debug_str,\"dr\"",
1041                    true, SectionKind::getMetadata());
1042   DwarfLocSection =
1043     getCOFFSection("\t.section\t.debug_loc,\"dr\"",
1044                    true, SectionKind::getMetadata());
1045   DwarfARangesSection =
1046     getCOFFSection("\t.section\t.debug_aranges,\"dr\"",
1047                    true, SectionKind::getMetadata());
1048   DwarfRangesSection =
1049     getCOFFSection("\t.section\t.debug_ranges,\"dr\"",
1050                    true, SectionKind::getMetadata());
1051   DwarfMacroInfoSection =
1052     getCOFFSection("\t.section\t.debug_macinfo,\"dr\"",
1053                    true, SectionKind::getMetadata());
1054 }
1055
1056 const MCSection *TargetLoweringObjectFileCOFF::
1057 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
1058                          Mangler *Mang, const TargetMachine &TM) const {
1059   return getCOFFSection(GV->getSection().c_str(), false, Kind);
1060 }
1061
1062 static const char *getCOFFSectionPrefixForUniqueGlobal(SectionKind Kind) {
1063   if (Kind.isText())
1064     return ".text$linkonce";
1065   if (Kind.isWriteable())
1066     return ".data$linkonce";
1067   return ".rdata$linkonce";
1068 }
1069
1070
1071 const MCSection *TargetLoweringObjectFileCOFF::
1072 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
1073                        Mangler *Mang, const TargetMachine &TM) const {
1074   assert(!Kind.isThreadLocal() && "Doesn't support TLS");
1075
1076   // If this global is linkonce/weak and the target handles this by emitting it
1077   // into a 'uniqued' section name, create and return the section now.
1078   if (GV->isWeakForLinker()) {
1079     const char *Prefix = getCOFFSectionPrefixForUniqueGlobal(Kind);
1080     std::string Name = Mang->makeNameProper(GV->getNameStr());
1081     return getCOFFSection((Prefix+Name).c_str(), false, Kind);
1082   }
1083
1084   if (Kind.isText())
1085     return getTextSection();
1086
1087   return getDataSection();
1088 }
1089