1 //===- lib/MC/ELFObjectWriter.cpp - ELF File Writer -------------------===// 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 ELF object file writer information. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "ELFObjectWriter.h" 15 #include "llvm/ADT/STLExtras.h" 16 #include "llvm/ADT/StringMap.h" 17 #include "llvm/ADT/Twine.h" 18 #include "llvm/MC/MCAsmBackend.h" 19 #include "llvm/MC/MCAsmLayout.h" 20 #include "llvm/MC/MCContext.h" 21 #include "llvm/MC/MCExpr.h" 22 #include "llvm/MC/MCSectionELF.h" 23 #include "llvm/MC/MCValue.h" 24 #include "llvm/Support/Debug.h" 25 #include "llvm/Support/ErrorHandling.h" 26 #include "llvm/Support/ELF.h" 27 #include "llvm/Support/CommandLine.h" 28 #include "llvm/ADT/Statistic.h" 29 #include "llvm/ADT/StringSwitch.h" 30 31 #include "../Target/X86/MCTargetDesc/X86FixupKinds.h" 32 #include "../Target/ARM/MCTargetDesc/ARMFixupKinds.h" 33 #include "../Target/PowerPC/MCTargetDesc/PPCFixupKinds.h" 34 35 #include <vector> 36 using namespace llvm; 37 38 #undef DEBUG_TYPE 39 #define DEBUG_TYPE "reloc-info" 40 41 bool ELFObjectWriter::isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind) { 42 const MCFixupKindInfo &FKI = 43 Asm.getBackend().getFixupKindInfo((MCFixupKind) Kind); 44 45 return FKI.Flags & MCFixupKindInfo::FKF_IsPCRel; 46 } 47 48 bool ELFObjectWriter::RelocNeedsGOT(MCSymbolRefExpr::VariantKind Variant) { 49 switch (Variant) { 50 default: 51 return false; 52 case MCSymbolRefExpr::VK_GOT: 53 case MCSymbolRefExpr::VK_PLT: 54 case MCSymbolRefExpr::VK_GOTPCREL: 55 case MCSymbolRefExpr::VK_GOTOFF: 56 case MCSymbolRefExpr::VK_TPOFF: 57 case MCSymbolRefExpr::VK_TLSGD: 58 case MCSymbolRefExpr::VK_GOTTPOFF: 59 case MCSymbolRefExpr::VK_INDNTPOFF: 60 case MCSymbolRefExpr::VK_NTPOFF: 61 case MCSymbolRefExpr::VK_GOTNTPOFF: 62 case MCSymbolRefExpr::VK_TLSLDM: 63 case MCSymbolRefExpr::VK_DTPOFF: 64 case MCSymbolRefExpr::VK_TLSLD: 65 return true; 66 } 67 } 68 69 ELFObjectWriter::~ELFObjectWriter() 70 {} 71 72 // Emit the ELF header. 73 void ELFObjectWriter::WriteHeader(uint64_t SectionDataSize, 74 unsigned NumberOfSections) { 75 // ELF Header 76 // ---------- 77 // 78 // Note 79 // ---- 80 // emitWord method behaves differently for ELF32 and ELF64, writing 81 // 4 bytes in the former and 8 in the latter. 82 83 Write8(0x7f); // e_ident[EI_MAG0] 84 Write8('E'); // e_ident[EI_MAG1] 85 Write8('L'); // e_ident[EI_MAG2] 86 Write8('F'); // e_ident[EI_MAG3] 87 88 Write8(is64Bit() ? ELF::ELFCLASS64 : ELF::ELFCLASS32); // e_ident[EI_CLASS] 89 90 // e_ident[EI_DATA] 91 Write8(isLittleEndian() ? ELF::ELFDATA2LSB : ELF::ELFDATA2MSB); 92 93 Write8(ELF::EV_CURRENT); // e_ident[EI_VERSION] 94 // e_ident[EI_OSABI] 95 switch (TargetObjectWriter->getOSType()) { 96 case Triple::FreeBSD: Write8(ELF::ELFOSABI_FREEBSD); break; 97 case Triple::Linux: Write8(ELF::ELFOSABI_LINUX); break; 98 default: Write8(ELF::ELFOSABI_NONE); break; 99 } 100 Write8(0); // e_ident[EI_ABIVERSION] 101 102 WriteZeros(ELF::EI_NIDENT - ELF::EI_PAD); 103 104 Write16(ELF::ET_REL); // e_type 105 106 Write16(TargetObjectWriter->getEMachine()); // e_machine = target 107 108 Write32(ELF::EV_CURRENT); // e_version 109 WriteWord(0); // e_entry, no entry point in .o file 110 WriteWord(0); // e_phoff, no program header for .o 111 WriteWord(SectionDataSize + (is64Bit() ? sizeof(ELF::Elf64_Ehdr) : 112 sizeof(ELF::Elf32_Ehdr))); // e_shoff = sec hdr table off in bytes 113 114 // e_flags = whatever the target wants 115 WriteEFlags(); 116 117 // e_ehsize = ELF header size 118 Write16(is64Bit() ? sizeof(ELF::Elf64_Ehdr) : sizeof(ELF::Elf32_Ehdr)); 119 120 Write16(0); // e_phentsize = prog header entry size 121 Write16(0); // e_phnum = # prog header entries = 0 122 123 // e_shentsize = Section header entry size 124 Write16(is64Bit() ? sizeof(ELF::Elf64_Shdr) : sizeof(ELF::Elf32_Shdr)); 125 126 // e_shnum = # of section header ents 127 if (NumberOfSections >= ELF::SHN_LORESERVE) 128 Write16(0); 129 else 130 Write16(NumberOfSections); 131 132 // e_shstrndx = Section # of '.shstrtab' 133 if (NumberOfSections >= ELF::SHN_LORESERVE) 134 Write16(ELF::SHN_XINDEX); 135 else 136 Write16(ShstrtabIndex); 137 } 138 139 void ELFObjectWriter::WriteSymbolEntry(MCDataFragment *SymtabF, 140 MCDataFragment *ShndxF, 141 uint64_t name, 142 uint8_t info, uint64_t value, 143 uint64_t size, uint8_t other, 144 uint32_t shndx, 145 bool Reserved) { 146 if (ShndxF) { 147 if (shndx >= ELF::SHN_LORESERVE && !Reserved) 148 String32(*ShndxF, shndx); 149 else 150 String32(*ShndxF, 0); 151 } 152 153 uint16_t Index = (shndx >= ELF::SHN_LORESERVE && !Reserved) ? 154 uint16_t(ELF::SHN_XINDEX) : shndx; 155 156 if (is64Bit()) { 157 String32(*SymtabF, name); // st_name 158 String8(*SymtabF, info); // st_info 159 String8(*SymtabF, other); // st_other 160 String16(*SymtabF, Index); // st_shndx 161 String64(*SymtabF, value); // st_value 162 String64(*SymtabF, size); // st_size 163 } else { 164 String32(*SymtabF, name); // st_name 165 String32(*SymtabF, value); // st_value 166 String32(*SymtabF, size); // st_size 167 String8(*SymtabF, info); // st_info 168 String8(*SymtabF, other); // st_other 169 String16(*SymtabF, Index); // st_shndx 170 } 171 } 172 173 uint64_t ELFObjectWriter::SymbolValue(MCSymbolData &Data, 174 const MCAsmLayout &Layout) { 175 if (Data.isCommon() && Data.isExternal()) 176 return Data.getCommonAlignment(); 177 178 const MCSymbol &Symbol = Data.getSymbol(); 179 180 if (Symbol.isAbsolute() && Symbol.isVariable()) { 181 if (const MCExpr *Value = Symbol.getVariableValue()) { 182 int64_t IntValue; 183 if (Value->EvaluateAsAbsolute(IntValue, Layout)) 184 return (uint64_t)IntValue; 185 } 186 } 187 188 if (!Symbol.isInSection()) 189 return 0; 190 191 192 if (Data.getFragment()) { 193 if (Data.getFlags() & ELF_Other_ThumbFunc) 194 return Layout.getSymbolOffset(&Data)+1; 195 else 196 return Layout.getSymbolOffset(&Data); 197 } 198 199 return 0; 200 } 201 202 void ELFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm, 203 const MCAsmLayout &Layout) { 204 // The presence of symbol versions causes undefined symbols and 205 // versions declared with @@@ to be renamed. 206 207 for (MCAssembler::symbol_iterator it = Asm.symbol_begin(), 208 ie = Asm.symbol_end(); it != ie; ++it) { 209 const MCSymbol &Alias = it->getSymbol(); 210 const MCSymbol &Symbol = Alias.AliasedSymbol(); 211 MCSymbolData &SD = Asm.getSymbolData(Symbol); 212 213 // Not an alias. 214 if (&Symbol == &Alias) 215 continue; 216 217 StringRef AliasName = Alias.getName(); 218 size_t Pos = AliasName.find('@'); 219 if (Pos == StringRef::npos) 220 continue; 221 222 // Aliases defined with .symvar copy the binding from the symbol they alias. 223 // This is the first place we are able to copy this information. 224 it->setExternal(SD.isExternal()); 225 MCELF::SetBinding(*it, MCELF::GetBinding(SD)); 226 227 StringRef Rest = AliasName.substr(Pos); 228 if (!Symbol.isUndefined() && !Rest.startswith("@@@")) 229 continue; 230 231 // FIXME: produce a better error message. 232 if (Symbol.isUndefined() && Rest.startswith("@@") && 233 !Rest.startswith("@@@")) 234 report_fatal_error("A @@ version cannot be undefined"); 235 236 Renames.insert(std::make_pair(&Symbol, &Alias)); 237 } 238 } 239 240 void ELFObjectWriter::WriteSymbol(MCDataFragment *SymtabF, 241 MCDataFragment *ShndxF, 242 ELFSymbolData &MSD, 243 const MCAsmLayout &Layout) { 244 MCSymbolData &OrigData = *MSD.SymbolData; 245 MCSymbolData &Data = 246 Layout.getAssembler().getSymbolData(OrigData.getSymbol().AliasedSymbol()); 247 248 bool IsReserved = Data.isCommon() || Data.getSymbol().isAbsolute() || 249 Data.getSymbol().isVariable(); 250 251 uint8_t Binding = MCELF::GetBinding(OrigData); 252 uint8_t Visibility = MCELF::GetVisibility(OrigData); 253 uint8_t Type = MCELF::GetType(Data); 254 255 uint8_t Info = (Binding << ELF_STB_Shift) | (Type << ELF_STT_Shift); 256 uint8_t Other = Visibility; 257 258 uint64_t Value = SymbolValue(Data, Layout); 259 uint64_t Size = 0; 260 261 assert(!(Data.isCommon() && !Data.isExternal())); 262 263 const MCExpr *ESize = Data.getSize(); 264 if (ESize) { 265 int64_t Res; 266 if (!ESize->EvaluateAsAbsolute(Res, Layout)) 267 report_fatal_error("Size expression must be absolute."); 268 Size = Res; 269 } 270 271 // Write out the symbol table entry 272 WriteSymbolEntry(SymtabF, ShndxF, MSD.StringIndex, Info, Value, 273 Size, Other, MSD.SectionIndex, IsReserved); 274 } 275 276 void ELFObjectWriter::WriteSymbolTable(MCDataFragment *SymtabF, 277 MCDataFragment *ShndxF, 278 const MCAssembler &Asm, 279 const MCAsmLayout &Layout, 280 const SectionIndexMapTy &SectionIndexMap) { 281 // The string table must be emitted first because we need the index 282 // into the string table for all the symbol names. 283 assert(StringTable.size() && "Missing string table"); 284 285 // FIXME: Make sure the start of the symbol table is aligned. 286 287 // The first entry is the undefined symbol entry. 288 WriteSymbolEntry(SymtabF, ShndxF, 0, 0, 0, 0, 0, 0, false); 289 290 // Write the symbol table entries. 291 LastLocalSymbolIndex = LocalSymbolData.size() + 1; 292 for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i) { 293 ELFSymbolData &MSD = LocalSymbolData[i]; 294 WriteSymbol(SymtabF, ShndxF, MSD, Layout); 295 } 296 297 // Write out a symbol table entry for each regular section. 298 for (MCAssembler::const_iterator i = Asm.begin(), e = Asm.end(); i != e; 299 ++i) { 300 const MCSectionELF &Section = 301 static_cast<const MCSectionELF&>(i->getSection()); 302 if (Section.getType() == ELF::SHT_RELA || 303 Section.getType() == ELF::SHT_REL || 304 Section.getType() == ELF::SHT_STRTAB || 305 Section.getType() == ELF::SHT_SYMTAB) 306 continue; 307 WriteSymbolEntry(SymtabF, ShndxF, 0, ELF::STT_SECTION, 0, 0, 308 ELF::STV_DEFAULT, SectionIndexMap.lookup(&Section), false); 309 LastLocalSymbolIndex++; 310 } 311 312 for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i) { 313 ELFSymbolData &MSD = ExternalSymbolData[i]; 314 MCSymbolData &Data = *MSD.SymbolData; 315 assert(((Data.getFlags() & ELF_STB_Global) || 316 (Data.getFlags() & ELF_STB_Weak)) && 317 "External symbol requires STB_GLOBAL or STB_WEAK flag"); 318 WriteSymbol(SymtabF, ShndxF, MSD, Layout); 319 if (MCELF::GetBinding(Data) == ELF::STB_LOCAL) 320 LastLocalSymbolIndex++; 321 } 322 323 for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i) { 324 ELFSymbolData &MSD = UndefinedSymbolData[i]; 325 MCSymbolData &Data = *MSD.SymbolData; 326 WriteSymbol(SymtabF, ShndxF, MSD, Layout); 327 if (MCELF::GetBinding(Data) == ELF::STB_LOCAL) 328 LastLocalSymbolIndex++; 329 } 330 } 331 332 const MCSymbol *ELFObjectWriter::SymbolToReloc(const MCAssembler &Asm, 333 const MCValue &Target, 334 const MCFragment &F, 335 const MCFixup &Fixup, 336 bool IsPCRel) const { 337 const MCSymbol &Symbol = Target.getSymA()->getSymbol(); 338 const MCSymbol &ASymbol = Symbol.AliasedSymbol(); 339 const MCSymbol *Renamed = Renames.lookup(&Symbol); 340 const MCSymbolData &SD = Asm.getSymbolData(Symbol); 341 342 if (ASymbol.isUndefined()) { 343 if (Renamed) 344 return Renamed; 345 return &ASymbol; 346 } 347 348 if (SD.isExternal()) { 349 if (Renamed) 350 return Renamed; 351 return &Symbol; 352 } 353 354 const MCSectionELF &Section = 355 static_cast<const MCSectionELF&>(ASymbol.getSection()); 356 const SectionKind secKind = Section.getKind(); 357 358 if (secKind.isBSS()) 359 return ExplicitRelSym(Asm, Target, F, Fixup, IsPCRel); 360 361 if (secKind.isThreadLocal()) { 362 if (Renamed) 363 return Renamed; 364 return &Symbol; 365 } 366 367 MCSymbolRefExpr::VariantKind Kind = Target.getSymA()->getKind(); 368 const MCSectionELF &Sec2 = 369 static_cast<const MCSectionELF&>(F.getParent()->getSection()); 370 371 if (&Sec2 != &Section && 372 (Kind == MCSymbolRefExpr::VK_PLT || 373 Kind == MCSymbolRefExpr::VK_GOTPCREL || 374 Kind == MCSymbolRefExpr::VK_GOTOFF)) { 375 if (Renamed) 376 return Renamed; 377 return &Symbol; 378 } 379 380 if (Section.getFlags() & ELF::SHF_MERGE) { 381 if (Target.getConstant() == 0) 382 return ExplicitRelSym(Asm, Target, F, Fixup, IsPCRel); 383 if (Renamed) 384 return Renamed; 385 return &Symbol; 386 } 387 388 return ExplicitRelSym(Asm, Target, F, Fixup, IsPCRel); 389 390 } 391 392 393 void ELFObjectWriter::RecordRelocation(const MCAssembler &Asm, 394 const MCAsmLayout &Layout, 395 const MCFragment *Fragment, 396 const MCFixup &Fixup, 397 MCValue Target, 398 uint64_t &FixedValue) { 399 int64_t Addend = 0; 400 int Index = 0; 401 int64_t Value = Target.getConstant(); 402 const MCSymbol *RelocSymbol = NULL; 403 404 bool IsPCRel = isFixupKindPCRel(Asm, Fixup.getKind()); 405 if (!Target.isAbsolute()) { 406 const MCSymbol &Symbol = Target.getSymA()->getSymbol(); 407 const MCSymbol &ASymbol = Symbol.AliasedSymbol(); 408 RelocSymbol = SymbolToReloc(Asm, Target, *Fragment, Fixup, IsPCRel); 409 410 if (const MCSymbolRefExpr *RefB = Target.getSymB()) { 411 const MCSymbol &SymbolB = RefB->getSymbol(); 412 MCSymbolData &SDB = Asm.getSymbolData(SymbolB); 413 IsPCRel = true; 414 415 // Offset of the symbol in the section 416 int64_t a = Layout.getSymbolOffset(&SDB); 417 418 // Ofeset of the relocation in the section 419 int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset(); 420 Value += b - a; 421 } 422 423 if (!RelocSymbol) { 424 MCSymbolData &SD = Asm.getSymbolData(ASymbol); 425 MCFragment *F = SD.getFragment(); 426 427 Index = F->getParent()->getOrdinal() + 1; 428 429 // Offset of the symbol in the section 430 Value += Layout.getSymbolOffset(&SD); 431 } else { 432 if (Asm.getSymbolData(Symbol).getFlags() & ELF_Other_Weakref) 433 WeakrefUsedInReloc.insert(RelocSymbol); 434 else 435 UsedInReloc.insert(RelocSymbol); 436 Index = -1; 437 } 438 Addend = Value; 439 // Compensate for the addend on i386. 440 if (is64Bit()) 441 Value = 0; 442 } 443 444 FixedValue = Value; 445 unsigned Type = GetRelocType(Target, Fixup, IsPCRel, 446 (RelocSymbol != 0), Addend); 447 448 uint64_t RelocOffset = Layout.getFragmentOffset(Fragment) + 449 Fixup.getOffset(); 450 451 adjustFixupOffset(Fixup, RelocOffset); 452 453 if (!hasRelocationAddend()) 454 Addend = 0; 455 456 if (is64Bit()) 457 assert(isInt<64>(Addend)); 458 else 459 assert(isInt<32>(Addend)); 460 461 ELFRelocationEntry ERE(RelocOffset, Index, Type, RelocSymbol, Addend); 462 Relocations[Fragment->getParent()].push_back(ERE); 463 } 464 465 466 uint64_t 467 ELFObjectWriter::getSymbolIndexInSymbolTable(const MCAssembler &Asm, 468 const MCSymbol *S) { 469 MCSymbolData &SD = Asm.getSymbolData(*S); 470 return SD.getIndex(); 471 } 472 473 bool ELFObjectWriter::isInSymtab(const MCAssembler &Asm, 474 const MCSymbolData &Data, 475 bool Used, bool Renamed) { 476 if (Data.getFlags() & ELF_Other_Weakref) 477 return false; 478 479 if (Used) 480 return true; 481 482 if (Renamed) 483 return false; 484 485 const MCSymbol &Symbol = Data.getSymbol(); 486 487 if (Symbol.getName() == "_GLOBAL_OFFSET_TABLE_") 488 return true; 489 490 const MCSymbol &A = Symbol.AliasedSymbol(); 491 if (Symbol.isVariable() && !A.isVariable() && A.isUndefined()) 492 return false; 493 494 bool IsGlobal = MCELF::GetBinding(Data) == ELF::STB_GLOBAL; 495 if (!Symbol.isVariable() && Symbol.isUndefined() && !IsGlobal) 496 return false; 497 498 if (!Asm.isSymbolLinkerVisible(Symbol) && !Symbol.isUndefined()) 499 return false; 500 501 if (Symbol.isTemporary()) 502 return false; 503 504 return true; 505 } 506 507 bool ELFObjectWriter::isLocal(const MCSymbolData &Data, bool isSignature, 508 bool isUsedInReloc) { 509 if (Data.isExternal()) 510 return false; 511 512 const MCSymbol &Symbol = Data.getSymbol(); 513 const MCSymbol &RefSymbol = Symbol.AliasedSymbol(); 514 515 if (RefSymbol.isUndefined() && !RefSymbol.isVariable()) { 516 if (isSignature && !isUsedInReloc) 517 return true; 518 519 return false; 520 } 521 522 return true; 523 } 524 525 void ELFObjectWriter::ComputeIndexMap(MCAssembler &Asm, 526 SectionIndexMapTy &SectionIndexMap, 527 const RelMapTy &RelMap) { 528 unsigned Index = 1; 529 for (MCAssembler::iterator it = Asm.begin(), 530 ie = Asm.end(); it != ie; ++it) { 531 const MCSectionELF &Section = 532 static_cast<const MCSectionELF &>(it->getSection()); 533 if (Section.getType() != ELF::SHT_GROUP) 534 continue; 535 SectionIndexMap[&Section] = Index++; 536 } 537 538 for (MCAssembler::iterator it = Asm.begin(), 539 ie = Asm.end(); it != ie; ++it) { 540 const MCSectionELF &Section = 541 static_cast<const MCSectionELF &>(it->getSection()); 542 if (Section.getType() == ELF::SHT_GROUP || 543 Section.getType() == ELF::SHT_REL || 544 Section.getType() == ELF::SHT_RELA) 545 continue; 546 SectionIndexMap[&Section] = Index++; 547 const MCSectionELF *RelSection = RelMap.lookup(&Section); 548 if (RelSection) 549 SectionIndexMap[RelSection] = Index++; 550 } 551 } 552 553 void ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm, 554 const SectionIndexMapTy &SectionIndexMap, 555 RevGroupMapTy RevGroupMap, 556 unsigned NumRegularSections) { 557 // FIXME: Is this the correct place to do this? 558 // FIXME: Why is an undefined reference to _GLOBAL_OFFSET_TABLE_ needed? 559 if (NeedsGOT) { 560 llvm::StringRef Name = "_GLOBAL_OFFSET_TABLE_"; 561 MCSymbol *Sym = Asm.getContext().GetOrCreateSymbol(Name); 562 MCSymbolData &Data = Asm.getOrCreateSymbolData(*Sym); 563 Data.setExternal(true); 564 MCELF::SetBinding(Data, ELF::STB_GLOBAL); 565 } 566 567 // Index 0 is always the empty string. 568 StringMap<uint64_t> StringIndexMap; 569 StringTable += '\x00'; 570 571 // FIXME: We could optimize suffixes in strtab in the same way we 572 // optimize them in shstrtab. 573 574 // Add the data for the symbols. 575 for (MCAssembler::symbol_iterator it = Asm.symbol_begin(), 576 ie = Asm.symbol_end(); it != ie; ++it) { 577 const MCSymbol &Symbol = it->getSymbol(); 578 579 bool Used = UsedInReloc.count(&Symbol); 580 bool WeakrefUsed = WeakrefUsedInReloc.count(&Symbol); 581 bool isSignature = RevGroupMap.count(&Symbol); 582 583 if (!isInSymtab(Asm, *it, 584 Used || WeakrefUsed || isSignature, 585 Renames.count(&Symbol))) 586 continue; 587 588 ELFSymbolData MSD; 589 MSD.SymbolData = it; 590 const MCSymbol &RefSymbol = Symbol.AliasedSymbol(); 591 592 // Undefined symbols are global, but this is the first place we 593 // are able to set it. 594 bool Local = isLocal(*it, isSignature, Used); 595 if (!Local && MCELF::GetBinding(*it) == ELF::STB_LOCAL) { 596 MCSymbolData &SD = Asm.getSymbolData(RefSymbol); 597 MCELF::SetBinding(*it, ELF::STB_GLOBAL); 598 MCELF::SetBinding(SD, ELF::STB_GLOBAL); 599 } 600 601 if (RefSymbol.isUndefined() && !Used && WeakrefUsed) 602 MCELF::SetBinding(*it, ELF::STB_WEAK); 603 604 if (it->isCommon()) { 605 assert(!Local); 606 MSD.SectionIndex = ELF::SHN_COMMON; 607 } else if (Symbol.isAbsolute() || RefSymbol.isVariable()) { 608 MSD.SectionIndex = ELF::SHN_ABS; 609 } else if (RefSymbol.isUndefined()) { 610 if (isSignature && !Used) 611 MSD.SectionIndex = SectionIndexMap.lookup(RevGroupMap[&Symbol]); 612 else 613 MSD.SectionIndex = ELF::SHN_UNDEF; 614 } else { 615 const MCSectionELF &Section = 616 static_cast<const MCSectionELF&>(RefSymbol.getSection()); 617 MSD.SectionIndex = SectionIndexMap.lookup(&Section); 618 if (MSD.SectionIndex >= ELF::SHN_LORESERVE) 619 NeedsSymtabShndx = true; 620 assert(MSD.SectionIndex && "Invalid section index!"); 621 } 622 623 // The @@@ in symbol version is replaced with @ in undefined symbols and 624 // @@ in defined ones. 625 StringRef Name = Symbol.getName(); 626 SmallString<32> Buf; 627 628 size_t Pos = Name.find("@@@"); 629 if (Pos != StringRef::npos) { 630 Buf += Name.substr(0, Pos); 631 unsigned Skip = MSD.SectionIndex == ELF::SHN_UNDEF ? 2 : 1; 632 Buf += Name.substr(Pos + Skip); 633 Name = Buf; 634 } 635 636 uint64_t &Entry = StringIndexMap[Name]; 637 if (!Entry) { 638 Entry = StringTable.size(); 639 StringTable += Name; 640 StringTable += '\x00'; 641 } 642 MSD.StringIndex = Entry; 643 if (MSD.SectionIndex == ELF::SHN_UNDEF) 644 UndefinedSymbolData.push_back(MSD); 645 else if (Local) 646 LocalSymbolData.push_back(MSD); 647 else 648 ExternalSymbolData.push_back(MSD); 649 } 650 651 // Symbols are required to be in lexicographic order. 652 array_pod_sort(LocalSymbolData.begin(), LocalSymbolData.end()); 653 array_pod_sort(ExternalSymbolData.begin(), ExternalSymbolData.end()); 654 array_pod_sort(UndefinedSymbolData.begin(), UndefinedSymbolData.end()); 655 656 // Set the symbol indices. Local symbols must come before all other 657 // symbols with non-local bindings. 658 unsigned Index = 1; 659 for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i) 660 LocalSymbolData[i].SymbolData->setIndex(Index++); 661 662 Index += NumRegularSections; 663 664 for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i) 665 ExternalSymbolData[i].SymbolData->setIndex(Index++); 666 for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i) 667 UndefinedSymbolData[i].SymbolData->setIndex(Index++); 668 } 669 670 void ELFObjectWriter::CreateRelocationSections(MCAssembler &Asm, 671 MCAsmLayout &Layout, 672 RelMapTy &RelMap) { 673 for (MCAssembler::const_iterator it = Asm.begin(), 674 ie = Asm.end(); it != ie; ++it) { 675 const MCSectionData &SD = *it; 676 if (Relocations[&SD].empty()) 677 continue; 678 679 MCContext &Ctx = Asm.getContext(); 680 const MCSectionELF &Section = 681 static_cast<const MCSectionELF&>(SD.getSection()); 682 683 const StringRef SectionName = Section.getSectionName(); 684 std::string RelaSectionName = hasRelocationAddend() ? ".rela" : ".rel"; 685 RelaSectionName += SectionName; 686 687 unsigned EntrySize; 688 if (hasRelocationAddend()) 689 EntrySize = is64Bit() ? sizeof(ELF::Elf64_Rela) : sizeof(ELF::Elf32_Rela); 690 else 691 EntrySize = is64Bit() ? sizeof(ELF::Elf64_Rel) : sizeof(ELF::Elf32_Rel); 692 693 const MCSectionELF *RelaSection = 694 Ctx.getELFSection(RelaSectionName, hasRelocationAddend() ? 695 ELF::SHT_RELA : ELF::SHT_REL, 0, 696 SectionKind::getReadOnly(), 697 EntrySize, ""); 698 RelMap[&Section] = RelaSection; 699 Asm.getOrCreateSectionData(*RelaSection); 700 } 701 } 702 703 void ELFObjectWriter::WriteRelocations(MCAssembler &Asm, MCAsmLayout &Layout, 704 const RelMapTy &RelMap) { 705 for (MCAssembler::const_iterator it = Asm.begin(), 706 ie = Asm.end(); it != ie; ++it) { 707 const MCSectionData &SD = *it; 708 const MCSectionELF &Section = 709 static_cast<const MCSectionELF&>(SD.getSection()); 710 711 const MCSectionELF *RelaSection = RelMap.lookup(&Section); 712 if (!RelaSection) 713 continue; 714 MCSectionData &RelaSD = Asm.getOrCreateSectionData(*RelaSection); 715 RelaSD.setAlignment(is64Bit() ? 8 : 4); 716 717 MCDataFragment *F = new MCDataFragment(&RelaSD); 718 WriteRelocationsFragment(Asm, F, &*it); 719 } 720 } 721 722 void ELFObjectWriter::WriteSecHdrEntry(uint32_t Name, uint32_t Type, 723 uint64_t Flags, uint64_t Address, 724 uint64_t Offset, uint64_t Size, 725 uint32_t Link, uint32_t Info, 726 uint64_t Alignment, 727 uint64_t EntrySize) { 728 Write32(Name); // sh_name: index into string table 729 Write32(Type); // sh_type 730 WriteWord(Flags); // sh_flags 731 WriteWord(Address); // sh_addr 732 WriteWord(Offset); // sh_offset 733 WriteWord(Size); // sh_size 734 Write32(Link); // sh_link 735 Write32(Info); // sh_info 736 WriteWord(Alignment); // sh_addralign 737 WriteWord(EntrySize); // sh_entsize 738 } 739 740 void ELFObjectWriter::WriteRelocationsFragment(const MCAssembler &Asm, 741 MCDataFragment *F, 742 const MCSectionData *SD) { 743 std::vector<ELFRelocationEntry> &Relocs = Relocations[SD]; 744 // sort by the r_offset just like gnu as does 745 array_pod_sort(Relocs.begin(), Relocs.end()); 746 747 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) { 748 ELFRelocationEntry entry = Relocs[e - i - 1]; 749 750 if (!entry.Index) 751 ; 752 else if (entry.Index < 0) 753 entry.Index = getSymbolIndexInSymbolTable(Asm, entry.Symbol); 754 else 755 entry.Index += LocalSymbolData.size(); 756 if (is64Bit()) { 757 String64(*F, entry.r_offset); 758 759 struct ELF::Elf64_Rela ERE64; 760 ERE64.setSymbolAndType(entry.Index, entry.Type); 761 String64(*F, ERE64.r_info); 762 763 if (hasRelocationAddend()) 764 String64(*F, entry.r_addend); 765 } else { 766 String32(*F, entry.r_offset); 767 768 struct ELF::Elf32_Rela ERE32; 769 ERE32.setSymbolAndType(entry.Index, entry.Type); 770 String32(*F, ERE32.r_info); 771 772 if (hasRelocationAddend()) 773 String32(*F, entry.r_addend); 774 } 775 } 776 } 777 778 static int compareBySuffix(const void *a, const void *b) { 779 const MCSectionELF *secA = *static_cast<const MCSectionELF* const *>(a); 780 const MCSectionELF *secB = *static_cast<const MCSectionELF* const *>(b); 781 const StringRef &NameA = secA->getSectionName(); 782 const StringRef &NameB = secB->getSectionName(); 783 const unsigned sizeA = NameA.size(); 784 const unsigned sizeB = NameB.size(); 785 const unsigned len = std::min(sizeA, sizeB); 786 for (unsigned int i = 0; i < len; ++i) { 787 char ca = NameA[sizeA - i - 1]; 788 char cb = NameB[sizeB - i - 1]; 789 if (ca != cb) 790 return cb - ca; 791 } 792 793 return sizeB - sizeA; 794 } 795 796 void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm, 797 MCAsmLayout &Layout, 798 SectionIndexMapTy &SectionIndexMap, 799 const RelMapTy &RelMap) { 800 MCContext &Ctx = Asm.getContext(); 801 MCDataFragment *F; 802 803 unsigned EntrySize = is64Bit() ? ELF::SYMENTRY_SIZE64 : ELF::SYMENTRY_SIZE32; 804 805 // We construct .shstrtab, .symtab and .strtab in this order to match gnu as. 806 const MCSectionELF *ShstrtabSection = 807 Ctx.getELFSection(".shstrtab", ELF::SHT_STRTAB, 0, 808 SectionKind::getReadOnly()); 809 MCSectionData &ShstrtabSD = Asm.getOrCreateSectionData(*ShstrtabSection); 810 ShstrtabSD.setAlignment(1); 811 812 const MCSectionELF *SymtabSection = 813 Ctx.getELFSection(".symtab", ELF::SHT_SYMTAB, 0, 814 SectionKind::getReadOnly(), 815 EntrySize, ""); 816 MCSectionData &SymtabSD = Asm.getOrCreateSectionData(*SymtabSection); 817 SymtabSD.setAlignment(is64Bit() ? 8 : 4); 818 819 MCSectionData *SymtabShndxSD = NULL; 820 821 if (NeedsSymtabShndx) { 822 const MCSectionELF *SymtabShndxSection = 823 Ctx.getELFSection(".symtab_shndx", ELF::SHT_SYMTAB_SHNDX, 0, 824 SectionKind::getReadOnly(), 4, ""); 825 SymtabShndxSD = &Asm.getOrCreateSectionData(*SymtabShndxSection); 826 SymtabShndxSD->setAlignment(4); 827 } 828 829 const MCSectionELF *StrtabSection; 830 StrtabSection = Ctx.getELFSection(".strtab", ELF::SHT_STRTAB, 0, 831 SectionKind::getReadOnly()); 832 MCSectionData &StrtabSD = Asm.getOrCreateSectionData(*StrtabSection); 833 StrtabSD.setAlignment(1); 834 835 ComputeIndexMap(Asm, SectionIndexMap, RelMap); 836 837 ShstrtabIndex = SectionIndexMap.lookup(ShstrtabSection); 838 SymbolTableIndex = SectionIndexMap.lookup(SymtabSection); 839 StringTableIndex = SectionIndexMap.lookup(StrtabSection); 840 841 // Symbol table 842 F = new MCDataFragment(&SymtabSD); 843 MCDataFragment *ShndxF = NULL; 844 if (NeedsSymtabShndx) { 845 ShndxF = new MCDataFragment(SymtabShndxSD); 846 } 847 WriteSymbolTable(F, ShndxF, Asm, Layout, SectionIndexMap); 848 849 F = new MCDataFragment(&StrtabSD); 850 F->getContents().append(StringTable.begin(), StringTable.end()); 851 852 F = new MCDataFragment(&ShstrtabSD); 853 854 std::vector<const MCSectionELF*> Sections; 855 for (MCAssembler::const_iterator it = Asm.begin(), 856 ie = Asm.end(); it != ie; ++it) { 857 const MCSectionELF &Section = 858 static_cast<const MCSectionELF&>(it->getSection()); 859 Sections.push_back(&Section); 860 } 861 array_pod_sort(Sections.begin(), Sections.end(), compareBySuffix); 862 863 // Section header string table. 864 // 865 // The first entry of a string table holds a null character so skip 866 // section 0. 867 uint64_t Index = 1; 868 F->getContents() += '\x00'; 869 870 for (unsigned int I = 0, E = Sections.size(); I != E; ++I) { 871 const MCSectionELF &Section = *Sections[I]; 872 873 StringRef Name = Section.getSectionName(); 874 if (I != 0) { 875 StringRef PreviousName = Sections[I - 1]->getSectionName(); 876 if (PreviousName.endswith(Name)) { 877 SectionStringTableIndex[&Section] = Index - Name.size() - 1; 878 continue; 879 } 880 } 881 // Remember the index into the string table so we can write it 882 // into the sh_name field of the section header table. 883 SectionStringTableIndex[&Section] = Index; 884 885 Index += Name.size() + 1; 886 F->getContents() += Name; 887 F->getContents() += '\x00'; 888 } 889 } 890 891 void ELFObjectWriter::CreateIndexedSections(MCAssembler &Asm, 892 MCAsmLayout &Layout, 893 GroupMapTy &GroupMap, 894 RevGroupMapTy &RevGroupMap, 895 SectionIndexMapTy &SectionIndexMap, 896 const RelMapTy &RelMap) { 897 // Create the .note.GNU-stack section if needed. 898 MCContext &Ctx = Asm.getContext(); 899 if (Asm.getNoExecStack()) { 900 const MCSectionELF *GnuStackSection = 901 Ctx.getELFSection(".note.GNU-stack", ELF::SHT_PROGBITS, 0, 902 SectionKind::getReadOnly()); 903 Asm.getOrCreateSectionData(*GnuStackSection); 904 } 905 906 // Build the groups 907 for (MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end(); 908 it != ie; ++it) { 909 const MCSectionELF &Section = 910 static_cast<const MCSectionELF&>(it->getSection()); 911 if (!(Section.getFlags() & ELF::SHF_GROUP)) 912 continue; 913 914 const MCSymbol *SignatureSymbol = Section.getGroup(); 915 Asm.getOrCreateSymbolData(*SignatureSymbol); 916 const MCSectionELF *&Group = RevGroupMap[SignatureSymbol]; 917 if (!Group) { 918 Group = Ctx.CreateELFGroupSection(); 919 MCSectionData &Data = Asm.getOrCreateSectionData(*Group); 920 Data.setAlignment(4); 921 MCDataFragment *F = new MCDataFragment(&Data); 922 String32(*F, ELF::GRP_COMDAT); 923 } 924 GroupMap[Group] = SignatureSymbol; 925 } 926 927 ComputeIndexMap(Asm, SectionIndexMap, RelMap); 928 929 // Add sections to the groups 930 for (MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end(); 931 it != ie; ++it) { 932 const MCSectionELF &Section = 933 static_cast<const MCSectionELF&>(it->getSection()); 934 if (!(Section.getFlags() & ELF::SHF_GROUP)) 935 continue; 936 const MCSectionELF *Group = RevGroupMap[Section.getGroup()]; 937 MCSectionData &Data = Asm.getOrCreateSectionData(*Group); 938 // FIXME: we could use the previous fragment 939 MCDataFragment *F = new MCDataFragment(&Data); 940 unsigned Index = SectionIndexMap.lookup(&Section); 941 String32(*F, Index); 942 } 943 } 944 945 void ELFObjectWriter::WriteSection(MCAssembler &Asm, 946 const SectionIndexMapTy &SectionIndexMap, 947 uint32_t GroupSymbolIndex, 948 uint64_t Offset, uint64_t Size, 949 uint64_t Alignment, 950 const MCSectionELF &Section) { 951 uint64_t sh_link = 0; 952 uint64_t sh_info = 0; 953 954 switch(Section.getType()) { 955 case ELF::SHT_DYNAMIC: 956 sh_link = SectionStringTableIndex[&Section]; 957 sh_info = 0; 958 break; 959 960 case ELF::SHT_REL: 961 case ELF::SHT_RELA: { 962 const MCSectionELF *SymtabSection; 963 const MCSectionELF *InfoSection; 964 SymtabSection = Asm.getContext().getELFSection(".symtab", ELF::SHT_SYMTAB, 965 0, 966 SectionKind::getReadOnly()); 967 sh_link = SectionIndexMap.lookup(SymtabSection); 968 assert(sh_link && ".symtab not found"); 969 970 // Remove ".rel" and ".rela" prefixes. 971 unsigned SecNameLen = (Section.getType() == ELF::SHT_REL) ? 4 : 5; 972 StringRef SectionName = Section.getSectionName().substr(SecNameLen); 973 974 InfoSection = Asm.getContext().getELFSection(SectionName, 975 ELF::SHT_PROGBITS, 0, 976 SectionKind::getReadOnly()); 977 sh_info = SectionIndexMap.lookup(InfoSection); 978 break; 979 } 980 981 case ELF::SHT_SYMTAB: 982 case ELF::SHT_DYNSYM: 983 sh_link = StringTableIndex; 984 sh_info = LastLocalSymbolIndex; 985 break; 986 987 case ELF::SHT_SYMTAB_SHNDX: 988 sh_link = SymbolTableIndex; 989 break; 990 991 case ELF::SHT_PROGBITS: 992 case ELF::SHT_STRTAB: 993 case ELF::SHT_NOBITS: 994 case ELF::SHT_NOTE: 995 case ELF::SHT_NULL: 996 case ELF::SHT_ARM_ATTRIBUTES: 997 case ELF::SHT_INIT_ARRAY: 998 case ELF::SHT_FINI_ARRAY: 999 case ELF::SHT_PREINIT_ARRAY: 1000 case ELF::SHT_X86_64_UNWIND: 1001 // Nothing to do. 1002 break; 1003 1004 case ELF::SHT_GROUP: { 1005 sh_link = SymbolTableIndex; 1006 sh_info = GroupSymbolIndex; 1007 break; 1008 } 1009 1010 default: 1011 assert(0 && "FIXME: sh_type value not supported!"); 1012 break; 1013 } 1014 1015 WriteSecHdrEntry(SectionStringTableIndex[&Section], Section.getType(), 1016 Section.getFlags(), 0, Offset, Size, sh_link, sh_info, 1017 Alignment, Section.getEntrySize()); 1018 } 1019 1020 bool ELFObjectWriter::IsELFMetaDataSection(const MCSectionData &SD) { 1021 return SD.getOrdinal() == ~UINT32_C(0) && 1022 !SD.getSection().isVirtualSection(); 1023 } 1024 1025 uint64_t ELFObjectWriter::DataSectionSize(const MCSectionData &SD) { 1026 uint64_t Ret = 0; 1027 for (MCSectionData::const_iterator i = SD.begin(), e = SD.end(); i != e; 1028 ++i) { 1029 const MCFragment &F = *i; 1030 assert(F.getKind() == MCFragment::FT_Data); 1031 Ret += cast<MCDataFragment>(F).getContents().size(); 1032 } 1033 return Ret; 1034 } 1035 1036 uint64_t ELFObjectWriter::GetSectionFileSize(const MCAsmLayout &Layout, 1037 const MCSectionData &SD) { 1038 if (IsELFMetaDataSection(SD)) 1039 return DataSectionSize(SD); 1040 return Layout.getSectionFileSize(&SD); 1041 } 1042 1043 uint64_t ELFObjectWriter::GetSectionAddressSize(const MCAsmLayout &Layout, 1044 const MCSectionData &SD) { 1045 if (IsELFMetaDataSection(SD)) 1046 return DataSectionSize(SD); 1047 return Layout.getSectionAddressSize(&SD); 1048 } 1049 1050 void ELFObjectWriter::WriteDataSectionData(MCAssembler &Asm, 1051 const MCAsmLayout &Layout, 1052 const MCSectionELF &Section) { 1053 uint64_t FileOff = OS.tell(); 1054 const MCSectionData &SD = Asm.getOrCreateSectionData(Section); 1055 1056 uint64_t Padding = OffsetToAlignment(FileOff, SD.getAlignment()); 1057 WriteZeros(Padding); 1058 FileOff += Padding; 1059 1060 FileOff += GetSectionFileSize(Layout, SD); 1061 1062 if (IsELFMetaDataSection(SD)) { 1063 for (MCSectionData::const_iterator i = SD.begin(), e = SD.end(); i != e; 1064 ++i) { 1065 const MCFragment &F = *i; 1066 assert(F.getKind() == MCFragment::FT_Data); 1067 WriteBytes(cast<MCDataFragment>(F).getContents().str()); 1068 } 1069 } else { 1070 Asm.WriteSectionData(&SD, Layout); 1071 } 1072 } 1073 1074 void ELFObjectWriter::WriteSectionHeader(MCAssembler &Asm, 1075 const GroupMapTy &GroupMap, 1076 const MCAsmLayout &Layout, 1077 const SectionIndexMapTy &SectionIndexMap, 1078 const SectionOffsetMapTy &SectionOffsetMap) { 1079 const unsigned NumSections = Asm.size() + 1; 1080 1081 std::vector<const MCSectionELF*> Sections; 1082 Sections.resize(NumSections - 1); 1083 1084 for (SectionIndexMapTy::const_iterator i= 1085 SectionIndexMap.begin(), e = SectionIndexMap.end(); i != e; ++i) { 1086 const std::pair<const MCSectionELF*, uint32_t> &p = *i; 1087 Sections[p.second - 1] = p.first; 1088 } 1089 1090 // Null section first. 1091 uint64_t FirstSectionSize = 1092 NumSections >= ELF::SHN_LORESERVE ? NumSections : 0; 1093 uint32_t FirstSectionLink = 1094 ShstrtabIndex >= ELF::SHN_LORESERVE ? ShstrtabIndex : 0; 1095 WriteSecHdrEntry(0, 0, 0, 0, 0, FirstSectionSize, FirstSectionLink, 0, 0, 0); 1096 1097 for (unsigned i = 0; i < NumSections - 1; ++i) { 1098 const MCSectionELF &Section = *Sections[i]; 1099 const MCSectionData &SD = Asm.getOrCreateSectionData(Section); 1100 uint32_t GroupSymbolIndex; 1101 if (Section.getType() != ELF::SHT_GROUP) 1102 GroupSymbolIndex = 0; 1103 else 1104 GroupSymbolIndex = getSymbolIndexInSymbolTable(Asm, 1105 GroupMap.lookup(&Section)); 1106 1107 uint64_t Size = GetSectionAddressSize(Layout, SD); 1108 1109 WriteSection(Asm, SectionIndexMap, GroupSymbolIndex, 1110 SectionOffsetMap.lookup(&Section), Size, 1111 SD.getAlignment(), Section); 1112 } 1113 } 1114 1115 void ELFObjectWriter::ComputeSectionOrder(MCAssembler &Asm, 1116 std::vector<const MCSectionELF*> &Sections) { 1117 for (MCAssembler::iterator it = Asm.begin(), 1118 ie = Asm.end(); it != ie; ++it) { 1119 const MCSectionELF &Section = 1120 static_cast<const MCSectionELF &>(it->getSection()); 1121 if (Section.getType() == ELF::SHT_GROUP) 1122 Sections.push_back(&Section); 1123 } 1124 1125 for (MCAssembler::iterator it = Asm.begin(), 1126 ie = Asm.end(); it != ie; ++it) { 1127 const MCSectionELF &Section = 1128 static_cast<const MCSectionELF &>(it->getSection()); 1129 if (Section.getType() != ELF::SHT_GROUP && 1130 Section.getType() != ELF::SHT_REL && 1131 Section.getType() != ELF::SHT_RELA) 1132 Sections.push_back(&Section); 1133 } 1134 1135 for (MCAssembler::iterator it = Asm.begin(), 1136 ie = Asm.end(); it != ie; ++it) { 1137 const MCSectionELF &Section = 1138 static_cast<const MCSectionELF &>(it->getSection()); 1139 if (Section.getType() == ELF::SHT_REL || 1140 Section.getType() == ELF::SHT_RELA) 1141 Sections.push_back(&Section); 1142 } 1143 } 1144 1145 void ELFObjectWriter::WriteObject(MCAssembler &Asm, 1146 const MCAsmLayout &Layout) { 1147 GroupMapTy GroupMap; 1148 RevGroupMapTy RevGroupMap; 1149 SectionIndexMapTy SectionIndexMap; 1150 1151 unsigned NumUserSections = Asm.size(); 1152 1153 DenseMap<const MCSectionELF*, const MCSectionELF*> RelMap; 1154 CreateRelocationSections(Asm, const_cast<MCAsmLayout&>(Layout), RelMap); 1155 1156 const unsigned NumUserAndRelocSections = Asm.size(); 1157 CreateIndexedSections(Asm, const_cast<MCAsmLayout&>(Layout), GroupMap, 1158 RevGroupMap, SectionIndexMap, RelMap); 1159 const unsigned AllSections = Asm.size(); 1160 const unsigned NumIndexedSections = AllSections - NumUserAndRelocSections; 1161 1162 unsigned NumRegularSections = NumUserSections + NumIndexedSections; 1163 1164 // Compute symbol table information. 1165 ComputeSymbolTable(Asm, SectionIndexMap, RevGroupMap, NumRegularSections); 1166 1167 1168 WriteRelocations(Asm, const_cast<MCAsmLayout&>(Layout), RelMap); 1169 1170 CreateMetadataSections(const_cast<MCAssembler&>(Asm), 1171 const_cast<MCAsmLayout&>(Layout), 1172 SectionIndexMap, 1173 RelMap); 1174 1175 uint64_t NaturalAlignment = is64Bit() ? 8 : 4; 1176 uint64_t HeaderSize = is64Bit() ? sizeof(ELF::Elf64_Ehdr) : 1177 sizeof(ELF::Elf32_Ehdr); 1178 uint64_t FileOff = HeaderSize; 1179 1180 std::vector<const MCSectionELF*> Sections; 1181 ComputeSectionOrder(Asm, Sections); 1182 unsigned NumSections = Sections.size(); 1183 SectionOffsetMapTy SectionOffsetMap; 1184 for (unsigned i = 0; i < NumRegularSections + 1; ++i) { 1185 const MCSectionELF &Section = *Sections[i]; 1186 const MCSectionData &SD = Asm.getOrCreateSectionData(Section); 1187 1188 FileOff = RoundUpToAlignment(FileOff, SD.getAlignment()); 1189 1190 // Remember the offset into the file for this section. 1191 SectionOffsetMap[&Section] = FileOff; 1192 1193 // Get the size of the section in the output file (including padding). 1194 FileOff += GetSectionFileSize(Layout, SD); 1195 } 1196 1197 FileOff = RoundUpToAlignment(FileOff, NaturalAlignment); 1198 1199 const unsigned SectionHeaderOffset = FileOff - HeaderSize; 1200 1201 uint64_t SectionHeaderEntrySize = is64Bit() ? 1202 sizeof(ELF::Elf64_Shdr) : sizeof(ELF::Elf32_Shdr); 1203 FileOff += (NumSections + 1) * SectionHeaderEntrySize; 1204 1205 for (unsigned i = NumRegularSections + 1; i < NumSections; ++i) { 1206 const MCSectionELF &Section = *Sections[i]; 1207 const MCSectionData &SD = Asm.getOrCreateSectionData(Section); 1208 1209 FileOff = RoundUpToAlignment(FileOff, SD.getAlignment()); 1210 1211 // Remember the offset into the file for this section. 1212 SectionOffsetMap[&Section] = FileOff; 1213 1214 // Get the size of the section in the output file (including padding). 1215 FileOff += GetSectionFileSize(Layout, SD); 1216 } 1217 1218 // Write out the ELF header ... 1219 WriteHeader(SectionHeaderOffset, NumSections + 1); 1220 1221 // ... then the regular sections ... 1222 // + because of .shstrtab 1223 for (unsigned i = 0; i < NumRegularSections + 1; ++i) 1224 WriteDataSectionData(Asm, Layout, *Sections[i]); 1225 1226 FileOff = OS.tell(); 1227 uint64_t Padding = OffsetToAlignment(FileOff, NaturalAlignment); 1228 WriteZeros(Padding); 1229 1230 // ... then the section header table ... 1231 WriteSectionHeader(Asm, GroupMap, Layout, SectionIndexMap, 1232 SectionOffsetMap); 1233 1234 FileOff = OS.tell(); 1235 1236 // ... and then the remainting sections ... 1237 for (unsigned i = NumRegularSections + 1; i < NumSections; ++i) 1238 WriteDataSectionData(Asm, Layout, *Sections[i]); 1239 } 1240 1241 bool 1242 ELFObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm, 1243 const MCSymbolData &DataA, 1244 const MCFragment &FB, 1245 bool InSet, 1246 bool IsPCRel) const { 1247 if (DataA.getFlags() & ELF_STB_Weak) 1248 return false; 1249 return MCObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl( 1250 Asm, DataA, FB,InSet, IsPCRel); 1251 } 1252 1253 MCObjectWriter *llvm::createELFObjectWriter(MCELFObjectTargetWriter *MOTW, 1254 raw_ostream &OS, 1255 bool IsLittleEndian) { 1256 switch (MOTW->getEMachine()) { 1257 case ELF::EM_386: 1258 case ELF::EM_X86_64: 1259 return new X86ELFObjectWriter(MOTW, OS, IsLittleEndian); break; 1260 case ELF::EM_ARM: 1261 return new ARMELFObjectWriter(MOTW, OS, IsLittleEndian); break; 1262 case ELF::EM_MBLAZE: 1263 return new MBlazeELFObjectWriter(MOTW, OS, IsLittleEndian); break; 1264 case ELF::EM_PPC: 1265 case ELF::EM_PPC64: 1266 return new PPCELFObjectWriter(MOTW, OS, IsLittleEndian); break; 1267 default: llvm_unreachable("Unsupported architecture"); break; 1268 } 1269 } 1270 1271 1272 /// START OF SUBCLASSES for ELFObjectWriter 1273 //===- ARMELFObjectWriter -------------------------------------------===// 1274 1275 ARMELFObjectWriter::ARMELFObjectWriter(MCELFObjectTargetWriter *MOTW, 1276 raw_ostream &_OS, 1277 bool IsLittleEndian) 1278 : ELFObjectWriter(MOTW, _OS, IsLittleEndian) 1279 {} 1280 1281 ARMELFObjectWriter::~ARMELFObjectWriter() 1282 {} 1283 1284 // FIXME: get the real EABI Version from the Triple. 1285 void ARMELFObjectWriter::WriteEFlags() { 1286 Write32(ELF::EF_ARM_EABIMASK & DefaultEABIVersion); 1287 } 1288 1289 // In ARM, _MergedGlobals and other most symbols get emitted directly. 1290 // I.e. not as an offset to a section symbol. 1291 // This code is an approximation of what ARM/gcc does. 1292 1293 STATISTIC(PCRelCount, "Total number of PIC Relocations"); 1294 STATISTIC(NonPCRelCount, "Total number of non-PIC relocations"); 1295 1296 const MCSymbol *ARMELFObjectWriter::ExplicitRelSym(const MCAssembler &Asm, 1297 const MCValue &Target, 1298 const MCFragment &F, 1299 const MCFixup &Fixup, 1300 bool IsPCRel) const { 1301 const MCSymbol &Symbol = Target.getSymA()->getSymbol(); 1302 bool EmitThisSym = false; 1303 1304 const MCSectionELF &Section = 1305 static_cast<const MCSectionELF&>(Symbol.getSection()); 1306 bool InNormalSection = true; 1307 unsigned RelocType = 0; 1308 RelocType = GetRelocTypeInner(Target, Fixup, IsPCRel); 1309 1310 DEBUG( 1311 const MCSymbolRefExpr::VariantKind Kind = Target.getSymA()->getKind(); 1312 MCSymbolRefExpr::VariantKind Kind2; 1313 Kind2 = Target.getSymB() ? Target.getSymB()->getKind() : 1314 MCSymbolRefExpr::VK_None; 1315 dbgs() << "considering symbol " 1316 << Section.getSectionName() << "/" 1317 << Symbol.getName() << "/" 1318 << " Rel:" << (unsigned)RelocType 1319 << " Kind: " << (int)Kind << "/" << (int)Kind2 1320 << " Tmp:" 1321 << Symbol.isAbsolute() << "/" << Symbol.isDefined() << "/" 1322 << Symbol.isVariable() << "/" << Symbol.isTemporary() 1323 << " Counts:" << PCRelCount << "/" << NonPCRelCount << "\n"); 1324 1325 if (IsPCRel) { ++PCRelCount; 1326 switch (RelocType) { 1327 default: 1328 // Most relocation types are emitted as explicit symbols 1329 InNormalSection = 1330 StringSwitch<bool>(Section.getSectionName()) 1331 .Case(".data.rel.ro.local", false) 1332 .Case(".data.rel", false) 1333 .Case(".bss", false) 1334 .Default(true); 1335 EmitThisSym = true; 1336 break; 1337 case ELF::R_ARM_ABS32: 1338 // But things get strange with R_ARM_ABS32 1339 // In this case, most things that go in .rodata show up 1340 // as section relative relocations 1341 InNormalSection = 1342 StringSwitch<bool>(Section.getSectionName()) 1343 .Case(".data.rel.ro.local", false) 1344 .Case(".data.rel", false) 1345 .Case(".rodata", false) 1346 .Case(".bss", false) 1347 .Default(true); 1348 EmitThisSym = false; 1349 break; 1350 } 1351 } else { 1352 NonPCRelCount++; 1353 InNormalSection = 1354 StringSwitch<bool>(Section.getSectionName()) 1355 .Case(".data.rel.ro.local", false) 1356 .Case(".rodata", false) 1357 .Case(".data.rel", false) 1358 .Case(".bss", false) 1359 .Default(true); 1360 1361 switch (RelocType) { 1362 default: EmitThisSym = true; break; 1363 case ELF::R_ARM_ABS32: EmitThisSym = false; break; 1364 } 1365 } 1366 1367 if (EmitThisSym) 1368 return &Symbol; 1369 if (! Symbol.isTemporary() && InNormalSection) { 1370 return &Symbol; 1371 } 1372 return NULL; 1373 } 1374 1375 // Need to examine the Fixup when determining whether to 1376 // emit the relocation as an explicit symbol or as a section relative 1377 // offset 1378 unsigned ARMELFObjectWriter::GetRelocType(const MCValue &Target, 1379 const MCFixup &Fixup, 1380 bool IsPCRel, 1381 bool IsRelocWithSymbol, 1382 int64_t Addend) { 1383 MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ? 1384 MCSymbolRefExpr::VK_None : Target.getSymA()->getKind(); 1385 1386 unsigned Type = GetRelocTypeInner(Target, Fixup, IsPCRel); 1387 1388 if (RelocNeedsGOT(Modifier)) 1389 NeedsGOT = true; 1390 1391 return Type; 1392 } 1393 1394 unsigned ARMELFObjectWriter::GetRelocTypeInner(const MCValue &Target, 1395 const MCFixup &Fixup, 1396 bool IsPCRel) const { 1397 MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ? 1398 MCSymbolRefExpr::VK_None : Target.getSymA()->getKind(); 1399 1400 unsigned Type = 0; 1401 if (IsPCRel) { 1402 switch ((unsigned)Fixup.getKind()) { 1403 default: assert(0 && "Unimplemented"); 1404 case FK_Data_4: 1405 switch (Modifier) { 1406 default: llvm_unreachable("Unsupported Modifier"); 1407 case MCSymbolRefExpr::VK_None: 1408 Type = ELF::R_ARM_REL32; 1409 break; 1410 case MCSymbolRefExpr::VK_ARM_TLSGD: 1411 assert(0 && "unimplemented"); 1412 break; 1413 case MCSymbolRefExpr::VK_ARM_GOTTPOFF: 1414 Type = ELF::R_ARM_TLS_IE32; 1415 break; 1416 } 1417 break; 1418 case ARM::fixup_arm_uncondbranch: 1419 switch (Modifier) { 1420 case MCSymbolRefExpr::VK_ARM_PLT: 1421 Type = ELF::R_ARM_PLT32; 1422 break; 1423 default: 1424 Type = ELF::R_ARM_CALL; 1425 break; 1426 } 1427 break; 1428 case ARM::fixup_arm_condbranch: 1429 Type = ELF::R_ARM_JUMP24; 1430 break; 1431 case ARM::fixup_arm_movt_hi16: 1432 case ARM::fixup_arm_movt_hi16_pcrel: 1433 Type = ELF::R_ARM_MOVT_PREL; 1434 break; 1435 case ARM::fixup_arm_movw_lo16: 1436 case ARM::fixup_arm_movw_lo16_pcrel: 1437 Type = ELF::R_ARM_MOVW_PREL_NC; 1438 break; 1439 case ARM::fixup_t2_movt_hi16: 1440 case ARM::fixup_t2_movt_hi16_pcrel: 1441 Type = ELF::R_ARM_THM_MOVT_PREL; 1442 break; 1443 case ARM::fixup_t2_movw_lo16: 1444 case ARM::fixup_t2_movw_lo16_pcrel: 1445 Type = ELF::R_ARM_THM_MOVW_PREL_NC; 1446 break; 1447 case ARM::fixup_arm_thumb_bl: 1448 case ARM::fixup_arm_thumb_blx: 1449 switch (Modifier) { 1450 case MCSymbolRefExpr::VK_ARM_PLT: 1451 Type = ELF::R_ARM_THM_CALL; 1452 break; 1453 default: 1454 Type = ELF::R_ARM_NONE; 1455 break; 1456 } 1457 break; 1458 } 1459 } else { 1460 switch ((unsigned)Fixup.getKind()) { 1461 default: llvm_unreachable("invalid fixup kind!"); 1462 case FK_Data_4: 1463 switch (Modifier) { 1464 default: llvm_unreachable("Unsupported Modifier"); break; 1465 case MCSymbolRefExpr::VK_ARM_GOT: 1466 Type = ELF::R_ARM_GOT_BREL; 1467 break; 1468 case MCSymbolRefExpr::VK_ARM_TLSGD: 1469 Type = ELF::R_ARM_TLS_GD32; 1470 break; 1471 case MCSymbolRefExpr::VK_ARM_TPOFF: 1472 Type = ELF::R_ARM_TLS_LE32; 1473 break; 1474 case MCSymbolRefExpr::VK_ARM_GOTTPOFF: 1475 Type = ELF::R_ARM_TLS_IE32; 1476 break; 1477 case MCSymbolRefExpr::VK_None: 1478 Type = ELF::R_ARM_ABS32; 1479 break; 1480 case MCSymbolRefExpr::VK_ARM_GOTOFF: 1481 Type = ELF::R_ARM_GOTOFF32; 1482 break; 1483 } 1484 break; 1485 case ARM::fixup_arm_ldst_pcrel_12: 1486 case ARM::fixup_arm_pcrel_10: 1487 case ARM::fixup_arm_adr_pcrel_12: 1488 case ARM::fixup_arm_thumb_bl: 1489 case ARM::fixup_arm_thumb_cb: 1490 case ARM::fixup_arm_thumb_cp: 1491 case ARM::fixup_arm_thumb_br: 1492 assert(0 && "Unimplemented"); 1493 break; 1494 case ARM::fixup_arm_uncondbranch: 1495 Type = ELF::R_ARM_CALL; 1496 break; 1497 case ARM::fixup_arm_condbranch: 1498 Type = ELF::R_ARM_JUMP24; 1499 break; 1500 case ARM::fixup_arm_movt_hi16: 1501 Type = ELF::R_ARM_MOVT_ABS; 1502 break; 1503 case ARM::fixup_arm_movw_lo16: 1504 Type = ELF::R_ARM_MOVW_ABS_NC; 1505 break; 1506 case ARM::fixup_t2_movt_hi16: 1507 Type = ELF::R_ARM_THM_MOVT_ABS; 1508 break; 1509 case ARM::fixup_t2_movw_lo16: 1510 Type = ELF::R_ARM_THM_MOVW_ABS_NC; 1511 break; 1512 } 1513 } 1514 1515 return Type; 1516 } 1517 1518 //===- PPCELFObjectWriter -------------------------------------------===// 1519 1520 PPCELFObjectWriter::PPCELFObjectWriter(MCELFObjectTargetWriter *MOTW, 1521 raw_ostream &_OS, 1522 bool IsLittleEndian) 1523 : ELFObjectWriter(MOTW, _OS, IsLittleEndian) { 1524 } 1525 1526 PPCELFObjectWriter::~PPCELFObjectWriter() { 1527 } 1528 1529 unsigned PPCELFObjectWriter::GetRelocType(const MCValue &Target, 1530 const MCFixup &Fixup, 1531 bool IsPCRel, 1532 bool IsRelocWithSymbol, 1533 int64_t Addend) { 1534 // determine the type of the relocation 1535 unsigned Type; 1536 if (IsPCRel) { 1537 switch ((unsigned)Fixup.getKind()) { 1538 default: 1539 llvm_unreachable("Unimplemented"); 1540 case PPC::fixup_ppc_br24: 1541 Type = ELF::R_PPC_REL24; 1542 break; 1543 case FK_PCRel_4: 1544 Type = ELF::R_PPC_REL32; 1545 break; 1546 } 1547 } else { 1548 switch ((unsigned)Fixup.getKind()) { 1549 default: llvm_unreachable("invalid fixup kind!"); 1550 case PPC::fixup_ppc_br24: 1551 Type = ELF::R_PPC_ADDR24; 1552 break; 1553 case PPC::fixup_ppc_brcond14: 1554 Type = ELF::R_PPC_ADDR14_BRTAKEN; // XXX: or BRNTAKEN?_ 1555 break; 1556 case PPC::fixup_ppc_ha16: 1557 Type = ELF::R_PPC_ADDR16_HA; 1558 break; 1559 case PPC::fixup_ppc_lo16: 1560 Type = ELF::R_PPC_ADDR16_LO; 1561 break; 1562 case PPC::fixup_ppc_lo14: 1563 Type = ELF::R_PPC_ADDR14; 1564 break; 1565 case FK_Data_4: 1566 Type = ELF::R_PPC_ADDR32; 1567 break; 1568 case FK_Data_2: 1569 Type = ELF::R_PPC_ADDR16; 1570 break; 1571 } 1572 } 1573 return Type; 1574 } 1575 1576 void 1577 PPCELFObjectWriter::adjustFixupOffset(const MCFixup &Fixup, uint64_t &RelocOffset) { 1578 switch ((unsigned)Fixup.getKind()) { 1579 case PPC::fixup_ppc_ha16: 1580 case PPC::fixup_ppc_lo16: 1581 RelocOffset += 2; 1582 break; 1583 default: 1584 break; 1585 } 1586 } 1587 1588 //===- MBlazeELFObjectWriter -------------------------------------------===// 1589 1590 MBlazeELFObjectWriter::MBlazeELFObjectWriter(MCELFObjectTargetWriter *MOTW, 1591 raw_ostream &_OS, 1592 bool IsLittleEndian) 1593 : ELFObjectWriter(MOTW, _OS, IsLittleEndian) { 1594 } 1595 1596 MBlazeELFObjectWriter::~MBlazeELFObjectWriter() { 1597 } 1598 1599 unsigned MBlazeELFObjectWriter::GetRelocType(const MCValue &Target, 1600 const MCFixup &Fixup, 1601 bool IsPCRel, 1602 bool IsRelocWithSymbol, 1603 int64_t Addend) { 1604 // determine the type of the relocation 1605 unsigned Type; 1606 if (IsPCRel) { 1607 switch ((unsigned)Fixup.getKind()) { 1608 default: 1609 llvm_unreachable("Unimplemented"); 1610 case FK_PCRel_4: 1611 Type = ELF::R_MICROBLAZE_64_PCREL; 1612 break; 1613 case FK_PCRel_2: 1614 Type = ELF::R_MICROBLAZE_32_PCREL; 1615 break; 1616 } 1617 } else { 1618 switch ((unsigned)Fixup.getKind()) { 1619 default: llvm_unreachable("invalid fixup kind!"); 1620 case FK_Data_4: 1621 Type = ((IsRelocWithSymbol || Addend !=0) 1622 ? ELF::R_MICROBLAZE_32 1623 : ELF::R_MICROBLAZE_64); 1624 break; 1625 case FK_Data_2: 1626 Type = ELF::R_MICROBLAZE_32; 1627 break; 1628 } 1629 } 1630 return Type; 1631 } 1632 1633 //===- X86ELFObjectWriter -------------------------------------------===// 1634 1635 1636 X86ELFObjectWriter::X86ELFObjectWriter(MCELFObjectTargetWriter *MOTW, 1637 raw_ostream &_OS, 1638 bool IsLittleEndian) 1639 : ELFObjectWriter(MOTW, _OS, IsLittleEndian) 1640 {} 1641 1642 X86ELFObjectWriter::~X86ELFObjectWriter() 1643 {} 1644 1645 unsigned X86ELFObjectWriter::GetRelocType(const MCValue &Target, 1646 const MCFixup &Fixup, 1647 bool IsPCRel, 1648 bool IsRelocWithSymbol, 1649 int64_t Addend) { 1650 // determine the type of the relocation 1651 1652 MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ? 1653 MCSymbolRefExpr::VK_None : Target.getSymA()->getKind(); 1654 unsigned Type; 1655 if (is64Bit()) { 1656 if (IsPCRel) { 1657 switch ((unsigned)Fixup.getKind()) { 1658 default: llvm_unreachable("invalid fixup kind!"); 1659 1660 case FK_Data_8: Type = ELF::R_X86_64_PC64; break; 1661 case FK_Data_4: Type = ELF::R_X86_64_PC32; break; 1662 case FK_Data_2: Type = ELF::R_X86_64_PC16; break; 1663 1664 case FK_PCRel_8: 1665 assert(Modifier == MCSymbolRefExpr::VK_None); 1666 Type = ELF::R_X86_64_PC64; 1667 break; 1668 case X86::reloc_signed_4byte: 1669 case X86::reloc_riprel_4byte_movq_load: 1670 case X86::reloc_riprel_4byte: 1671 case FK_PCRel_4: 1672 switch (Modifier) { 1673 default: 1674 llvm_unreachable("Unimplemented"); 1675 case MCSymbolRefExpr::VK_None: 1676 Type = ELF::R_X86_64_PC32; 1677 break; 1678 case MCSymbolRefExpr::VK_PLT: 1679 Type = ELF::R_X86_64_PLT32; 1680 break; 1681 case MCSymbolRefExpr::VK_GOTPCREL: 1682 Type = ELF::R_X86_64_GOTPCREL; 1683 break; 1684 case MCSymbolRefExpr::VK_GOTTPOFF: 1685 Type = ELF::R_X86_64_GOTTPOFF; 1686 break; 1687 case MCSymbolRefExpr::VK_TLSGD: 1688 Type = ELF::R_X86_64_TLSGD; 1689 break; 1690 case MCSymbolRefExpr::VK_TLSLD: 1691 Type = ELF::R_X86_64_TLSLD; 1692 break; 1693 } 1694 break; 1695 case FK_PCRel_2: 1696 assert(Modifier == MCSymbolRefExpr::VK_None); 1697 Type = ELF::R_X86_64_PC16; 1698 break; 1699 case FK_PCRel_1: 1700 assert(Modifier == MCSymbolRefExpr::VK_None); 1701 Type = ELF::R_X86_64_PC8; 1702 break; 1703 } 1704 } else { 1705 switch ((unsigned)Fixup.getKind()) { 1706 default: llvm_unreachable("invalid fixup kind!"); 1707 case FK_Data_8: Type = ELF::R_X86_64_64; break; 1708 case X86::reloc_signed_4byte: 1709 switch (Modifier) { 1710 default: 1711 llvm_unreachable("Unimplemented"); 1712 case MCSymbolRefExpr::VK_None: 1713 Type = ELF::R_X86_64_32S; 1714 break; 1715 case MCSymbolRefExpr::VK_GOT: 1716 Type = ELF::R_X86_64_GOT32; 1717 break; 1718 case MCSymbolRefExpr::VK_GOTPCREL: 1719 Type = ELF::R_X86_64_GOTPCREL; 1720 break; 1721 case MCSymbolRefExpr::VK_TPOFF: 1722 Type = ELF::R_X86_64_TPOFF32; 1723 break; 1724 case MCSymbolRefExpr::VK_DTPOFF: 1725 Type = ELF::R_X86_64_DTPOFF32; 1726 break; 1727 } 1728 break; 1729 case FK_Data_4: 1730 Type = ELF::R_X86_64_32; 1731 break; 1732 case FK_Data_2: Type = ELF::R_X86_64_16; break; 1733 case FK_PCRel_1: 1734 case FK_Data_1: Type = ELF::R_X86_64_8; break; 1735 } 1736 } 1737 } else { 1738 if (IsPCRel) { 1739 switch (Modifier) { 1740 default: 1741 llvm_unreachable("Unimplemented"); 1742 case MCSymbolRefExpr::VK_None: 1743 Type = ELF::R_386_PC32; 1744 break; 1745 case MCSymbolRefExpr::VK_PLT: 1746 Type = ELF::R_386_PLT32; 1747 break; 1748 } 1749 } else { 1750 switch ((unsigned)Fixup.getKind()) { 1751 default: llvm_unreachable("invalid fixup kind!"); 1752 1753 case X86::reloc_global_offset_table: 1754 Type = ELF::R_386_GOTPC; 1755 break; 1756 1757 // FIXME: Should we avoid selecting reloc_signed_4byte in 32 bit mode 1758 // instead? 1759 case X86::reloc_signed_4byte: 1760 case FK_PCRel_4: 1761 case FK_Data_4: 1762 switch (Modifier) { 1763 default: 1764 llvm_unreachable("Unimplemented"); 1765 case MCSymbolRefExpr::VK_None: 1766 Type = ELF::R_386_32; 1767 break; 1768 case MCSymbolRefExpr::VK_GOT: 1769 Type = ELF::R_386_GOT32; 1770 break; 1771 case MCSymbolRefExpr::VK_GOTOFF: 1772 Type = ELF::R_386_GOTOFF; 1773 break; 1774 case MCSymbolRefExpr::VK_TLSGD: 1775 Type = ELF::R_386_TLS_GD; 1776 break; 1777 case MCSymbolRefExpr::VK_TPOFF: 1778 Type = ELF::R_386_TLS_LE_32; 1779 break; 1780 case MCSymbolRefExpr::VK_INDNTPOFF: 1781 Type = ELF::R_386_TLS_IE; 1782 break; 1783 case MCSymbolRefExpr::VK_NTPOFF: 1784 Type = ELF::R_386_TLS_LE; 1785 break; 1786 case MCSymbolRefExpr::VK_GOTNTPOFF: 1787 Type = ELF::R_386_TLS_GOTIE; 1788 break; 1789 case MCSymbolRefExpr::VK_TLSLDM: 1790 Type = ELF::R_386_TLS_LDM; 1791 break; 1792 case MCSymbolRefExpr::VK_DTPOFF: 1793 Type = ELF::R_386_TLS_LDO_32; 1794 break; 1795 case MCSymbolRefExpr::VK_GOTTPOFF: 1796 Type = ELF::R_386_TLS_IE_32; 1797 break; 1798 } 1799 break; 1800 case FK_Data_2: Type = ELF::R_386_16; break; 1801 case FK_PCRel_1: 1802 case FK_Data_1: Type = ELF::R_386_8; break; 1803 } 1804 } 1805 } 1806 1807 if (RelocNeedsGOT(Modifier)) 1808 NeedsGOT = true; 1809 1810 return Type; 1811 } 1812