lib/ObjectYAML/ELFEmitter.cpp

   1 //===- yaml2elf - Convert YAML to a ELF object file -----------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 ///
   9 /// \file
  10 /// The ELF component of yaml2obj.
  11 ///
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/ADT/ArrayRef.h"
  15 #include "llvm/ADT/StringSet.h"
  16 #include "llvm/BinaryFormat/ELF.h"
  17 #include "llvm/MC/StringTableBuilder.h"
  18 #include "llvm/Object/ELFObjectFile.h"
  19 #include "llvm/ObjectYAML/ELFYAML.h"
  20 #include "llvm/ObjectYAML/yaml2obj.h"
  21 #include "llvm/Support/EndianStream.h"
  22 #include "llvm/Support/LEB128.h"
  23 #include "llvm/Support/MemoryBuffer.h"
  24 #include "llvm/Support/WithColor.h"
  25 #include "llvm/Support/YAMLTraits.h"
  26 #include "llvm/Support/raw_ostream.h"
  27
  28 using namespace llvm;
  29
  30 // This class is used to build up a contiguous binary blob while keeping
  31 // track of an offset in the output (which notionally begins at
  32 // `InitialOffset`).
  33 namespace {
  34 class ContiguousBlobAccumulator {
  35   const uint64_t InitialOffset;
  36   SmallVector<char, 128> Buf;
  37   raw_svector_ostream OS;
  38
  39   /// \returns The new offset.
  40   uint64_t padToAlignment(unsigned Align) {
  41     if (Align == 0)
  42       Align = 1;
  43     uint64_t CurrentOffset = InitialOffset + OS.tell();
  44     uint64_t AlignedOffset = alignTo(CurrentOffset, Align);
  45     OS.write_zeros(AlignedOffset - CurrentOffset);
  46     return AlignedOffset; // == CurrentOffset;
  47   }
  48
  49 public:
  50   ContiguousBlobAccumulator(uint64_t InitialOffset_)
  51       : InitialOffset(InitialOffset_), Buf(), OS(Buf) {}
  52   template <class Integer>
  53   raw_ostream &getOSAndAlignedOffset(Integer &Offset, unsigned Align) {
  54     Offset = padToAlignment(Align);
  55     return OS;
  56   }
  57   void writeBlobToStream(raw_ostream &Out) { Out << OS.str(); }
  58 };
  59
  60 // Used to keep track of section and symbol names, so that in the YAML file
  61 // sections and symbols can be referenced by name instead of by index.
  62 class NameToIdxMap {
  63   StringMap<unsigned> Map;
  64
  65 public:
  66   /// \Returns false if name is already present in the map.
  67   bool addName(StringRef Name, unsigned Ndx) {
  68     return Map.insert({Name, Ndx}).second;
  69   }
  70   /// \Returns false if name is not present in the map.
  71   bool lookup(StringRef Name, unsigned &Idx) const {
  72     auto I = Map.find(Name);
  73     if (I == Map.end())
  74       return false;
  75     Idx = I->getValue();
  76     return true;
  77   }
  78   /// Asserts if name is not present in the map.
  79   unsigned get(StringRef Name) const {
  80     unsigned Idx;
  81     if (lookup(Name, Idx))
  82       return Idx;
  83     assert(false && "Expected section not found in index");
  84     return 0;
  85   }
  86   unsigned size() const { return Map.size(); }
  87 };
  88
  89 /// "Single point of truth" for the ELF file construction.
  90 /// TODO: This class still has a ways to go before it is truly a "single
  91 /// point of truth".
  92 template <class ELFT> class ELFState {
  93   typedef typename ELFT::Ehdr Elf_Ehdr;
  94   typedef typename ELFT::Phdr Elf_Phdr;
  95   typedef typename ELFT::Shdr Elf_Shdr;
  96   typedef typename ELFT::Sym Elf_Sym;
  97   typedef typename ELFT::Rel Elf_Rel;
  98   typedef typename ELFT::Rela Elf_Rela;
  99   typedef typename ELFT::Relr Elf_Relr;
 100   typedef typename ELFT::Dyn Elf_Dyn;
 101
 102   enum class SymtabType { Static, Dynamic };
 103
 104   /// The future ".strtab" section.
 105   StringTableBuilder DotStrtab{StringTableBuilder::ELF};
 106
 107   /// The future ".shstrtab" section.
 108   StringTableBuilder DotShStrtab{StringTableBuilder::ELF};
 109
 110   /// The future ".dynstr" section.
 111   StringTableBuilder DotDynstr{StringTableBuilder::ELF};
 112
 113   NameToIdxMap SN2I;
 114   NameToIdxMap SymN2I;
 115   NameToIdxMap DynSymN2I;
 116   ELFYAML::Object &Doc;
 117
 118   bool HasError = false;
 119   yaml::ErrorHandler ErrHandler;
 120   void reportError(const Twine &Msg);
 121
 122   std::vector<Elf_Sym> toELFSymbols(ArrayRef<ELFYAML::Symbol> Symbols,
 123                                     const StringTableBuilder &Strtab);
 124   unsigned toSectionIndex(StringRef S, StringRef LocSec, StringRef LocSym = "");
 125   unsigned toSymbolIndex(StringRef S, StringRef LocSec, bool IsDynamic);
 126
 127   void buildSectionIndex();
 128   void buildSymbolIndexes();
 129   void initProgramHeaders(std::vector<Elf_Phdr> &PHeaders);
 130   bool initImplicitHeader(ContiguousBlobAccumulator &CBA, Elf_Shdr &Header,
 131                           StringRef SecName, ELFYAML::Section *YAMLSec);
 132   void initSectionHeaders(std::vector<Elf_Shdr> &SHeaders,
 133                           ContiguousBlobAccumulator &CBA);
 134   void initSymtabSectionHeader(Elf_Shdr &SHeader, SymtabType STType,
 135                                ContiguousBlobAccumulator &CBA,
 136                                ELFYAML::Section *YAMLSec);
 137   void initStrtabSectionHeader(Elf_Shdr &SHeader, StringRef Name,
 138                                StringTableBuilder &STB,
 139                                ContiguousBlobAccumulator &CBA,
 140                                ELFYAML::Section *YAMLSec);
 141   void setProgramHeaderLayout(std::vector<Elf_Phdr> &PHeaders,
 142                               std::vector<Elf_Shdr> &SHeaders);
 143   void finalizeStrings();
 144   void writeELFHeader(ContiguousBlobAccumulator &CBA, raw_ostream &OS);
 145   void writeSectionContent(Elf_Shdr &SHeader,
 146                            const ELFYAML::RawContentSection &Section,
 147                            ContiguousBlobAccumulator &CBA);
 148   void writeSectionContent(Elf_Shdr &SHeader,
 149                            const ELFYAML::RelocationSection &Section,
 150                            ContiguousBlobAccumulator &CBA);
 151   void writeSectionContent(Elf_Shdr &SHeader, const ELFYAML::Group &Group,
 152                            ContiguousBlobAccumulator &CBA);
 153   void writeSectionContent(Elf_Shdr &SHeader,
 154                            const ELFYAML::SymtabShndxSection &Shndx,
 155                            ContiguousBlobAccumulator &CBA);
 156   void writeSectionContent(Elf_Shdr &SHeader,
 157                            const ELFYAML::SymverSection &Section,
 158                            ContiguousBlobAccumulator &CBA);
 159   void writeSectionContent(Elf_Shdr &SHeader,
 160                            const ELFYAML::VerneedSection &Section,
 161                            ContiguousBlobAccumulator &CBA);
 162   void writeSectionContent(Elf_Shdr &SHeader,
 163                            const ELFYAML::VerdefSection &Section,
 164                            ContiguousBlobAccumulator &CBA);
 165   void writeSectionContent(Elf_Shdr &SHeader,
 166                            const ELFYAML::MipsABIFlags &Section,
 167                            ContiguousBlobAccumulator &CBA);
 168   void writeSectionContent(Elf_Shdr &SHeader,
 169                            const ELFYAML::DynamicSection &Section,
 170                            ContiguousBlobAccumulator &CBA);
 171   void writeSectionContent(Elf_Shdr &SHeader,
 172                            const ELFYAML::StackSizesSection &Section,
 173                            ContiguousBlobAccumulator &CBA);
 174   void writeSectionContent(Elf_Shdr &SHeader,
 175                            const ELFYAML::HashSection &Section,
 176                            ContiguousBlobAccumulator &CBA);
 177   ELFState(ELFYAML::Object &D, yaml::ErrorHandler EH);
 178
 179 public:
 180   static bool writeELF(raw_ostream &OS, ELFYAML::Object &Doc,
 181                        yaml::ErrorHandler EH);
 182 };
 183 } // end anonymous namespace
 184
 185 template <class T> static size_t arrayDataSize(ArrayRef<T> A) {
 186   return A.size() * sizeof(T);
 187 }
 188
 189 template <class T> static void writeArrayData(raw_ostream &OS, ArrayRef<T> A) {
 190   OS.write((const char *)A.data(), arrayDataSize(A));
 191 }
 192
 193 template <class T> static void zero(T &Obj) { memset(&Obj, 0, sizeof(Obj)); }
 194
 195 template <class ELFT>
 196 ELFState<ELFT>::ELFState(ELFYAML::Object &D, yaml::ErrorHandler EH)
 197     : Doc(D), ErrHandler(EH) {
 198   StringSet<> DocSections;
 199   for (std::unique_ptr<ELFYAML::Section> &D : Doc.Sections)
 200     if (!D->Name.empty())
 201       DocSections.insert(D->Name);
 202
 203   // Insert SHT_NULL section implicitly when it is not defined in YAML.
 204   if (Doc.Sections.empty() || Doc.Sections.front()->Type != ELF::SHT_NULL)
 205     Doc.Sections.insert(
 206         Doc.Sections.begin(),
 207         std::make_unique<ELFYAML::Section>(
 208             ELFYAML::Section::SectionKind::RawContent, /*IsImplicit=*/true));
 209
 210   std::vector<StringRef> ImplicitSections = {".symtab", ".strtab", ".shstrtab"};
 211   if (!Doc.DynamicSymbols.empty())
 212     ImplicitSections.insert(ImplicitSections.end(), {".dynsym", ".dynstr"});
 213
 214   // Insert placeholders for implicit sections that are not
 215   // defined explicitly in YAML.
 216   for (StringRef SecName : ImplicitSections) {
 217     if (DocSections.count(SecName))
 218       continue;
 219
 220     std::unique_ptr<ELFYAML::Section> Sec = std::make_unique<ELFYAML::Section>(
 221         ELFYAML::Section::SectionKind::RawContent, true /*IsImplicit*/);
 222     Sec->Name = SecName;
 223     Doc.Sections.push_back(std::move(Sec));
 224   }
 225 }
 226
 227 template <class ELFT>
 228 void ELFState<ELFT>::writeELFHeader(ContiguousBlobAccumulator &CBA, raw_ostream &OS) {
 229   using namespace llvm::ELF;
 230
 231   Elf_Ehdr Header;
 232   zero(Header);
 233   Header.e_ident[EI_MAG0] = 0x7f;
 234   Header.e_ident[EI_MAG1] = 'E';
 235   Header.e_ident[EI_MAG2] = 'L';
 236   Header.e_ident[EI_MAG3] = 'F';
 237   Header.e_ident[EI_CLASS] = ELFT::Is64Bits ? ELFCLASS64 : ELFCLASS32;
 238   Header.e_ident[EI_DATA] = Doc.Header.Data;
 239   Header.e_ident[EI_VERSION] = EV_CURRENT;
 240   Header.e_ident[EI_OSABI] = Doc.Header.OSABI;
 241   Header.e_ident[EI_ABIVERSION] = Doc.Header.ABIVersion;
 242   Header.e_type = Doc.Header.Type;
 243   Header.e_machine = Doc.Header.Machine;
 244   Header.e_version = EV_CURRENT;
 245   Header.e_entry = Doc.Header.Entry;
 246   Header.e_phoff = Doc.ProgramHeaders.size() ? sizeof(Header) : 0;
 247   Header.e_flags = Doc.Header.Flags;
 248   Header.e_ehsize = sizeof(Elf_Ehdr);
 249   Header.e_phentsize = Doc.ProgramHeaders.size() ? sizeof(Elf_Phdr) : 0;
 250   Header.e_phnum = Doc.ProgramHeaders.size();
 251
 252   Header.e_shentsize =
 253       Doc.Header.SHEntSize ? (uint16_t)*Doc.Header.SHEntSize : sizeof(Elf_Shdr);
 254   // Immediately following the ELF header and program headers.
 255   // Align the start of the section header and write the ELF header.
 256   uint64_t SHOff;
 257   CBA.getOSAndAlignedOffset(SHOff, sizeof(typename ELFT::uint));
 258   Header.e_shoff =
 259       Doc.Header.SHOff ? typename ELFT::uint(*Doc.Header.SHOff) : SHOff;
 260   Header.e_shnum =
 261       Doc.Header.SHNum ? (uint16_t)*Doc.Header.SHNum : Doc.Sections.size();
 262   Header.e_shstrndx = Doc.Header.SHStrNdx ? (uint16_t)*Doc.Header.SHStrNdx
 263                                           : SN2I.get(".shstrtab");
 264
 265   OS.write((const char *)&Header, sizeof(Header));
 266 }
 267
 268 template <class ELFT>
 269 void ELFState<ELFT>::initProgramHeaders(std::vector<Elf_Phdr> &PHeaders) {
 270   for (const auto &YamlPhdr : Doc.ProgramHeaders) {
 271     Elf_Phdr Phdr;
 272     Phdr.p_type = YamlPhdr.Type;
 273     Phdr.p_flags = YamlPhdr.Flags;
 274     Phdr.p_vaddr = YamlPhdr.VAddr;
 275     Phdr.p_paddr = YamlPhdr.PAddr;
 276     PHeaders.push_back(Phdr);
 277   }
 278 }
 279
 280 template <class ELFT>
 281 unsigned ELFState<ELFT>::toSectionIndex(StringRef S, StringRef LocSec,
 282                                         StringRef LocSym) {
 283   unsigned Index;
 284   if (SN2I.lookup(S, Index) || to_integer(S, Index))
 285     return Index;
 286
 287   assert(LocSec.empty() || LocSym.empty());
 288   if (!LocSym.empty())
 289     reportError("unknown section referenced: '" + S + "' by YAML symbol '" +
 290                 LocSym + "'");
 291   else
 292     reportError("unknown section referenced: '" + S + "' by YAML section '" +
 293                 LocSec + "'");
 294   return 0;
 295 }
 296
 297 template <class ELFT>
 298 unsigned ELFState<ELFT>::toSymbolIndex(StringRef S, StringRef LocSec,
 299                                        bool IsDynamic) {
 300   const NameToIdxMap &SymMap = IsDynamic ? DynSymN2I : SymN2I;
 301   unsigned Index;
 302   // Here we try to look up S in the symbol table. If it is not there,
 303   // treat its value as a symbol index.
 304   if (!SymMap.lookup(S, Index) && !to_integer(S, Index)) {
 305     reportError("unknown symbol referenced: '" + S + "' by YAML section '" +
 306                 LocSec + "'");
 307     return 0;
 308   }
 309   return Index;
 310 }
 311
 312 template <class ELFT>
 313 bool ELFState<ELFT>::initImplicitHeader(ContiguousBlobAccumulator &CBA,
 314                                         Elf_Shdr &Header, StringRef SecName,
 315                                         ELFYAML::Section *YAMLSec) {
 316   // Check if the header was already initialized.
 317   if (Header.sh_offset)
 318     return false;
 319
 320   if (SecName == ".symtab")
 321     initSymtabSectionHeader(Header, SymtabType::Static, CBA, YAMLSec);
 322   else if (SecName == ".strtab")
 323     initStrtabSectionHeader(Header, SecName, DotStrtab, CBA, YAMLSec);
 324   else if (SecName == ".shstrtab")
 325     initStrtabSectionHeader(Header, SecName, DotShStrtab, CBA, YAMLSec);
 326   else if (SecName == ".dynsym")
 327     initSymtabSectionHeader(Header, SymtabType::Dynamic, CBA, YAMLSec);
 328   else if (SecName == ".dynstr")
 329     initStrtabSectionHeader(Header, SecName, DotDynstr, CBA, YAMLSec);
 330   else
 331     return false;
 332
 333   // Override the fields if requested.
 334   if (YAMLSec) {
 335     if (YAMLSec->ShName)
 336       Header.sh_name = *YAMLSec->ShName;
 337     if (YAMLSec->ShOffset)
 338       Header.sh_offset = *YAMLSec->ShOffset;
 339     if (YAMLSec->ShSize)
 340       Header.sh_size = *YAMLSec->ShSize;
 341   }
 342
 343   return true;
 344 }
 345
 346 StringRef llvm::ELFYAML::dropUniqueSuffix(StringRef S) {
 347   size_t SuffixPos = S.rfind(" [");
 348   if (SuffixPos == StringRef::npos)
 349     return S;
 350   return S.substr(0, SuffixPos);
 351 }
 352
 353 template <class ELFT>
 354 void ELFState<ELFT>::initSectionHeaders(std::vector<Elf_Shdr> &SHeaders,
 355                                         ContiguousBlobAccumulator &CBA) {
 356   // Ensure SHN_UNDEF entry is present. An all-zero section header is a
 357   // valid SHN_UNDEF entry since SHT_NULL == 0.
 358   SHeaders.resize(Doc.Sections.size());
 359
 360   for (size_t I = 0; I < Doc.Sections.size(); ++I) {
 361     ELFYAML::Section *Sec = Doc.Sections[I].get();
 362     if (I == 0 && Sec->IsImplicit)
 363       continue;
 364
 365     // We have a few sections like string or symbol tables that are usually
 366     // added implicitly to the end. However, if they are explicitly specified
 367     // in the YAML, we need to write them here. This ensures the file offset
 368     // remains correct.
 369     Elf_Shdr &SHeader = SHeaders[I];
 370     if (initImplicitHeader(CBA, SHeader, Sec->Name,
 371                            Sec->IsImplicit ? nullptr : Sec))
 372       continue;
 373
 374     assert(Sec && "It can't be null unless it is an implicit section. But all "
 375                   "implicit sections should already have been handled above.");
 376
 377     SHeader.sh_name =
 378         DotShStrtab.getOffset(ELFYAML::dropUniqueSuffix(Sec->Name));
 379     SHeader.sh_type = Sec->Type;
 380     if (Sec->Flags)
 381       SHeader.sh_flags = *Sec->Flags;
 382     SHeader.sh_addr = Sec->Address;
 383     SHeader.sh_addralign = Sec->AddressAlign;
 384
 385     if (!Sec->Link.empty())
 386       SHeader.sh_link = toSectionIndex(Sec->Link, Sec->Name);
 387
 388     if (I == 0) {
 389       if (auto RawSec = dyn_cast<ELFYAML::RawContentSection>(Sec)) {
 390         // We do not write any content for special SHN_UNDEF section.
 391         if (RawSec->Size)
 392           SHeader.sh_size = *RawSec->Size;
 393         if (RawSec->Info)
 394           SHeader.sh_info = *RawSec->Info;
 395       }
 396       if (Sec->EntSize)
 397         SHeader.sh_entsize = *Sec->EntSize;
 398     } else if (auto S = dyn_cast<ELFYAML::RawContentSection>(Sec)) {
 399       writeSectionContent(SHeader, *S, CBA);
 400     } else if (auto S = dyn_cast<ELFYAML::SymtabShndxSection>(Sec)) {
 401       writeSectionContent(SHeader, *S, CBA);
 402     } else if (auto S = dyn_cast<ELFYAML::RelocationSection>(Sec)) {
 403       writeSectionContent(SHeader, *S, CBA);
 404     } else if (auto S = dyn_cast<ELFYAML::Group>(Sec)) {
 405       writeSectionContent(SHeader, *S, CBA);
 406     } else if (auto S = dyn_cast<ELFYAML::MipsABIFlags>(Sec)) {
 407       writeSectionContent(SHeader, *S, CBA);
 408     } else if (auto S = dyn_cast<ELFYAML::NoBitsSection>(Sec)) {
 409       SHeader.sh_entsize = 0;
 410       SHeader.sh_size = S->Size;
 411       // SHT_NOBITS section does not have content
 412       // so just to setup the section offset.
 413       CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
 414     } else if (auto S = dyn_cast<ELFYAML::DynamicSection>(Sec)) {
 415       writeSectionContent(SHeader, *S, CBA);
 416     } else if (auto S = dyn_cast<ELFYAML::SymverSection>(Sec)) {
 417       writeSectionContent(SHeader, *S, CBA);
 418     } else if (auto S = dyn_cast<ELFYAML::VerneedSection>(Sec)) {
 419       writeSectionContent(SHeader, *S, CBA);
 420     } else if (auto S = dyn_cast<ELFYAML::VerdefSection>(Sec)) {
 421       writeSectionContent(SHeader, *S, CBA);
 422     } else if (auto S = dyn_cast<ELFYAML::StackSizesSection>(Sec)) {
 423       writeSectionContent(SHeader, *S, CBA);
 424     } else if (auto S = dyn_cast<ELFYAML::HashSection>(Sec)) {
 425       writeSectionContent(SHeader, *S, CBA);
 426     } else {
 427       llvm_unreachable("Unknown section type");
 428     }
 429
 430     // Override the fields if requested.
 431     if (Sec) {
 432       if (Sec->ShName)
 433         SHeader.sh_name = *Sec->ShName;
 434       if (Sec->ShOffset)
 435         SHeader.sh_offset = *Sec->ShOffset;
 436       if (Sec->ShSize)
 437         SHeader.sh_size = *Sec->ShSize;
 438     }
 439   }
 440 }
 441
 442 static size_t findFirstNonGlobal(ArrayRef<ELFYAML::Symbol> Symbols) {
 443   for (size_t I = 0; I < Symbols.size(); ++I)
 444     if (Symbols[I].Binding.value != ELF::STB_LOCAL)
 445       return I;
 446   return Symbols.size();
 447 }
 448
 449 static uint64_t writeContent(raw_ostream &OS,
 450                              const Optional<yaml::BinaryRef> &Content,
 451                              const Optional<llvm::yaml::Hex64> &Size) {
 452   size_t ContentSize = 0;
 453   if (Content) {
 454     Content->writeAsBinary(OS);
 455     ContentSize = Content->binary_size();
 456   }
 457
 458   if (!Size)
 459     return ContentSize;
 460
 461   OS.write_zeros(*Size - ContentSize);
 462   return *Size;
 463 }
 464
 465 template <class ELFT>
 466 std::vector<typename ELFT::Sym>
 467 ELFState<ELFT>::toELFSymbols(ArrayRef<ELFYAML::Symbol> Symbols,
 468                              const StringTableBuilder &Strtab) {
 469   std::vector<Elf_Sym> Ret;
 470   Ret.resize(Symbols.size() + 1);
 471
 472   size_t I = 0;
 473   for (const auto &Sym : Symbols) {
 474     Elf_Sym &Symbol = Ret[++I];
 475
 476     // If NameIndex, which contains the name offset, is explicitly specified, we
 477     // use it. This is useful for preparing broken objects. Otherwise, we add
 478     // the specified Name to the string table builder to get its offset.
 479     if (Sym.NameIndex)
 480       Symbol.st_name = *Sym.NameIndex;
 481     else if (!Sym.Name.empty())
 482       Symbol.st_name = Strtab.getOffset(ELFYAML::dropUniqueSuffix(Sym.Name));
 483
 484     Symbol.setBindingAndType(Sym.Binding, Sym.Type);
 485     if (!Sym.Section.empty())
 486       Symbol.st_shndx = toSectionIndex(Sym.Section, "", Sym.Name);
 487     else if (Sym.Index)
 488       Symbol.st_shndx = *Sym.Index;
 489
 490     Symbol.st_value = Sym.Value;
 491     Symbol.st_other = Sym.Other ? *Sym.Other : 0;
 492     Symbol.st_size = Sym.Size;
 493   }
 494
 495   return Ret;
 496 }
 497
 498 template <class ELFT>
 499 void ELFState<ELFT>::initSymtabSectionHeader(Elf_Shdr &SHeader,
 500                                              SymtabType STType,
 501                                              ContiguousBlobAccumulator &CBA,
 502                                              ELFYAML::Section *YAMLSec) {
 503
 504   bool IsStatic = STType == SymtabType::Static;
 505   const auto &Symbols = IsStatic ? Doc.Symbols : Doc.DynamicSymbols;
 506
 507   ELFYAML::RawContentSection *RawSec =
 508       dyn_cast_or_null<ELFYAML::RawContentSection>(YAMLSec);
 509   if (RawSec && !Symbols.empty() && (RawSec->Content || RawSec->Size)) {
 510     if (RawSec->Content)
 511       reportError("cannot specify both `Content` and " +
 512                   (IsStatic ? Twine("`Symbols`") : Twine("`DynamicSymbols`")) +
 513                   " for symbol table section '" + RawSec->Name + "'");
 514     if (RawSec->Size)
 515       reportError("cannot specify both `Size` and " +
 516                   (IsStatic ? Twine("`Symbols`") : Twine("`DynamicSymbols`")) +
 517                   " for symbol table section '" + RawSec->Name + "'");
 518     return;
 519   }
 520
 521   zero(SHeader);
 522   SHeader.sh_name = DotShStrtab.getOffset(IsStatic ? ".symtab" : ".dynsym");
 523
 524   if (YAMLSec)
 525     SHeader.sh_type = YAMLSec->Type;
 526   else
 527     SHeader.sh_type = IsStatic ? ELF::SHT_SYMTAB : ELF::SHT_DYNSYM;
 528
 529   if (RawSec && !RawSec->Link.empty()) {
 530     // If the Link field is explicitly defined in the document,
 531     // we should use it.
 532     SHeader.sh_link = toSectionIndex(RawSec->Link, RawSec->Name);
 533   } else {
 534     // When we describe the .dynsym section in the document explicitly, it is
 535     // allowed to omit the "DynamicSymbols" tag. In this case .dynstr is not
 536     // added implicitly and we should be able to leave the Link zeroed if
 537     // .dynstr is not defined.
 538     unsigned Link = 0;
 539     if (IsStatic)
 540       Link = SN2I.get(".strtab");
 541     else
 542       SN2I.lookup(".dynstr", Link);
 543     SHeader.sh_link = Link;
 544   }
 545
 546   if (YAMLSec && YAMLSec->Flags)
 547     SHeader.sh_flags = *YAMLSec->Flags;
 548   else if (!IsStatic)
 549     SHeader.sh_flags = ELF::SHF_ALLOC;
 550
 551   // If the symbol table section is explicitly described in the YAML
 552   // then we should set the fields requested.
 553   SHeader.sh_info = (RawSec && RawSec->Info) ? (unsigned)(*RawSec->Info)
 554                                              : findFirstNonGlobal(Symbols) + 1;
 555   SHeader.sh_entsize = (YAMLSec && YAMLSec->EntSize)
 556                            ? (uint64_t)(*YAMLSec->EntSize)
 557                            : sizeof(Elf_Sym);
 558   SHeader.sh_addralign = YAMLSec ? (uint64_t)YAMLSec->AddressAlign : 8;
 559   SHeader.sh_addr = YAMLSec ? (uint64_t)YAMLSec->Address : 0;
 560
 561   auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
 562   if (RawSec && (RawSec->Content || RawSec->Size)) {
 563     assert(Symbols.empty());
 564     SHeader.sh_size = writeContent(OS, RawSec->Content, RawSec->Size);
 565     return;
 566   }
 567
 568   std::vector<Elf_Sym> Syms =
 569       toELFSymbols(Symbols, IsStatic ? DotStrtab : DotDynstr);
 570   writeArrayData(OS, makeArrayRef(Syms));
 571   SHeader.sh_size = arrayDataSize(makeArrayRef(Syms));
 572 }
 573
 574 template <class ELFT>
 575 void ELFState<ELFT>::initStrtabSectionHeader(Elf_Shdr &SHeader, StringRef Name,
 576                                              StringTableBuilder &STB,
 577                                              ContiguousBlobAccumulator &CBA,
 578                                              ELFYAML::Section *YAMLSec) {
 579   zero(SHeader);
 580   SHeader.sh_name = DotShStrtab.getOffset(Name);
 581   SHeader.sh_type = YAMLSec ? YAMLSec->Type : ELF::SHT_STRTAB;
 582   SHeader.sh_addralign = YAMLSec ? (uint64_t)YAMLSec->AddressAlign : 1;
 583
 584   ELFYAML::RawContentSection *RawSec =
 585       dyn_cast_or_null<ELFYAML::RawContentSection>(YAMLSec);
 586
 587   auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
 588   if (RawSec && (RawSec->Content || RawSec->Size)) {
 589     SHeader.sh_size = writeContent(OS, RawSec->Content, RawSec->Size);
 590   } else {
 591     STB.write(OS);
 592     SHeader.sh_size = STB.getSize();
 593   }
 594
 595   if (YAMLSec && YAMLSec->EntSize)
 596     SHeader.sh_entsize = *YAMLSec->EntSize;
 597
 598   if (RawSec && RawSec->Info)
 599     SHeader.sh_info = *RawSec->Info;
 600
 601   if (YAMLSec && YAMLSec->Flags)
 602     SHeader.sh_flags = *YAMLSec->Flags;
 603   else if (Name == ".dynstr")
 604     SHeader.sh_flags = ELF::SHF_ALLOC;
 605
 606   // If the section is explicitly described in the YAML
 607   // then we want to use its section address.
 608   if (YAMLSec)
 609     SHeader.sh_addr = YAMLSec->Address;
 610 }
 611
 612 template <class ELFT> void ELFState<ELFT>::reportError(const Twine &Msg) {
 613   ErrHandler(Msg);
 614   HasError = true;
 615 }
 616
 617 template <class ELFT>
 618 void ELFState<ELFT>::setProgramHeaderLayout(std::vector<Elf_Phdr> &PHeaders,
 619                                             std::vector<Elf_Shdr> &SHeaders) {
 620   uint32_t PhdrIdx = 0;
 621   for (auto &YamlPhdr : Doc.ProgramHeaders) {
 622     Elf_Phdr &PHeader = PHeaders[PhdrIdx++];
 623
 624     std::vector<Elf_Shdr *> Sections;
 625     for (const ELFYAML::SectionName &SecName : YamlPhdr.Sections) {
 626       unsigned Index;
 627       if (!SN2I.lookup(SecName.Section, Index)) {
 628         reportError("unknown section referenced: '" + SecName.Section +
 629                     "' by program header");
 630         continue;
 631       }
 632       Sections.push_back(&SHeaders[Index]);
 633     }
 634
 635     if (YamlPhdr.Offset) {
 636       PHeader.p_offset = *YamlPhdr.Offset;
 637     } else {
 638       if (YamlPhdr.Sections.size())
 639         PHeader.p_offset = UINT32_MAX;
 640       else
 641         PHeader.p_offset = 0;
 642
 643       // Find the minimum offset for the program header.
 644       for (Elf_Shdr *SHeader : Sections)
 645         PHeader.p_offset = std::min(PHeader.p_offset, SHeader->sh_offset);
 646     }
 647
 648     // Find the maximum offset of the end of a section in order to set p_filesz
 649     // and p_memsz. When setting p_filesz, trailing SHT_NOBITS sections are not
 650     // counted.
 651     uint64_t FileOffset = PHeader.p_offset, MemOffset = PHeader.p_offset;
 652     for (Elf_Shdr *SHeader : Sections) {
 653       uint64_t End = SHeader->sh_offset + SHeader->sh_size;
 654       MemOffset = std::max(MemOffset, End);
 655
 656       if (SHeader->sh_type != llvm::ELF::SHT_NOBITS)
 657         FileOffset = std::max(FileOffset, End);
 658     }
 659
 660     // Set the file size and the memory size if not set explicitly.
 661     PHeader.p_filesz = YamlPhdr.FileSize ? uint64_t(*YamlPhdr.FileSize)
 662                                          : FileOffset - PHeader.p_offset;
 663     PHeader.p_memsz = YamlPhdr.MemSize ? uint64_t(*YamlPhdr.MemSize)
 664                                        : MemOffset - PHeader.p_offset;
 665
 666     if (YamlPhdr.Align) {
 667       PHeader.p_align = *YamlPhdr.Align;
 668     } else {
 669       // Set the alignment of the segment to be the maximum alignment of the
 670       // sections so that by default the segment has a valid and sensible
 671       // alignment.
 672       PHeader.p_align = 1;
 673       for (Elf_Shdr *SHeader : Sections)
 674         PHeader.p_align = std::max(PHeader.p_align, SHeader->sh_addralign);
 675     }
 676   }
 677 }
 678
 679 template <class ELFT>
 680 void ELFState<ELFT>::writeSectionContent(
 681     Elf_Shdr &SHeader, const ELFYAML::RawContentSection &Section,
 682     ContiguousBlobAccumulator &CBA) {
 683   raw_ostream &OS =
 684       CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
 685   SHeader.sh_size = writeContent(OS, Section.Content, Section.Size);
 686
 687   if (Section.EntSize)
 688     SHeader.sh_entsize = *Section.EntSize;
 689   else if (Section.Type == llvm::ELF::SHT_RELR)
 690     SHeader.sh_entsize = sizeof(Elf_Relr);
 691   else
 692     SHeader.sh_entsize = 0;
 693
 694   if (Section.Info)
 695     SHeader.sh_info = *Section.Info;
 696 }
 697
 698 static bool isMips64EL(const ELFYAML::Object &Doc) {
 699   return Doc.Header.Machine == ELFYAML::ELF_EM(llvm::ELF::EM_MIPS) &&
 700          Doc.Header.Class == ELFYAML::ELF_ELFCLASS(ELF::ELFCLASS64) &&
 701          Doc.Header.Data == ELFYAML::ELF_ELFDATA(ELF::ELFDATA2LSB);
 702 }
 703
 704 template <class ELFT>
 705 void ELFState<ELFT>::writeSectionContent(
 706     Elf_Shdr &SHeader, const ELFYAML::RelocationSection &Section,
 707     ContiguousBlobAccumulator &CBA) {
 708   assert((Section.Type == llvm::ELF::SHT_REL ||
 709           Section.Type == llvm::ELF::SHT_RELA) &&
 710          "Section type is not SHT_REL nor SHT_RELA");
 711
 712   bool IsRela = Section.Type == llvm::ELF::SHT_RELA;
 713   SHeader.sh_entsize = IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel);
 714   SHeader.sh_size = SHeader.sh_entsize * Section.Relocations.size();
 715
 716   // For relocation section set link to .symtab by default.
 717   if (Section.Link.empty())
 718     SHeader.sh_link = SN2I.get(".symtab");
 719
 720   if (!Section.RelocatableSec.empty())
 721     SHeader.sh_info = toSectionIndex(Section.RelocatableSec, Section.Name);
 722
 723   auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
 724   for (const auto &Rel : Section.Relocations) {
 725     unsigned SymIdx = Rel.Symbol ? toSymbolIndex(*Rel.Symbol, Section.Name,
 726                                                  Section.Link == ".dynsym")
 727                                  : 0;
 728     if (IsRela) {
 729       Elf_Rela REntry;
 730       zero(REntry);
 731       REntry.r_offset = Rel.Offset;
 732       REntry.r_addend = Rel.Addend;
 733       REntry.setSymbolAndType(SymIdx, Rel.Type, isMips64EL(Doc));
 734       OS.write((const char *)&REntry, sizeof(REntry));
 735     } else {
 736       Elf_Rel REntry;
 737       zero(REntry);
 738       REntry.r_offset = Rel.Offset;
 739       REntry.setSymbolAndType(SymIdx, Rel.Type, isMips64EL(Doc));
 740       OS.write((const char *)&REntry, sizeof(REntry));
 741     }
 742   }
 743 }
 744
 745 template <class ELFT>
 746 void ELFState<ELFT>::writeSectionContent(
 747     Elf_Shdr &SHeader, const ELFYAML::SymtabShndxSection &Shndx,
 748     ContiguousBlobAccumulator &CBA) {
 749   raw_ostream &OS =
 750       CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
 751
 752   for (uint32_t E : Shndx.Entries)
 753     support::endian::write<uint32_t>(OS, E, ELFT::TargetEndianness);
 754
 755   SHeader.sh_entsize = Shndx.EntSize ? (uint64_t)*Shndx.EntSize : 4;
 756   SHeader.sh_size = Shndx.Entries.size() * SHeader.sh_entsize;
 757 }
 758
 759 template <class ELFT>
 760 void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
 761                                          const ELFYAML::Group &Section,
 762                                          ContiguousBlobAccumulator &CBA) {
 763   assert(Section.Type == llvm::ELF::SHT_GROUP &&
 764          "Section type is not SHT_GROUP");
 765
 766   SHeader.sh_entsize = 4;
 767   SHeader.sh_size = SHeader.sh_entsize * Section.Members.size();
 768   SHeader.sh_info =
 769       toSymbolIndex(Section.Signature, Section.Name, /*IsDynamic=*/false);
 770
 771   raw_ostream &OS =
 772       CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
 773
 774   for (const ELFYAML::SectionOrType &Member : Section.Members) {
 775     unsigned int SectionIndex = 0;
 776     if (Member.sectionNameOrType == "GRP_COMDAT")
 777       SectionIndex = llvm::ELF::GRP_COMDAT;
 778     else
 779       SectionIndex = toSectionIndex(Member.sectionNameOrType, Section.Name);
 780     support::endian::write<uint32_t>(OS, SectionIndex, ELFT::TargetEndianness);
 781   }
 782 }
 783
 784 template <class ELFT>
 785 void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
 786                                          const ELFYAML::SymverSection &Section,
 787                                          ContiguousBlobAccumulator &CBA) {
 788   raw_ostream &OS =
 789       CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
 790   for (uint16_t Version : Section.Entries)
 791     support::endian::write<uint16_t>(OS, Version, ELFT::TargetEndianness);
 792
 793   SHeader.sh_entsize = Section.EntSize ? (uint64_t)*Section.EntSize : 2;
 794   SHeader.sh_size = Section.Entries.size() * SHeader.sh_entsize;
 795 }
 796
 797 template <class ELFT>
 798 void ELFState<ELFT>::writeSectionContent(
 799     Elf_Shdr &SHeader, const ELFYAML::StackSizesSection &Section,
 800     ContiguousBlobAccumulator &CBA) {
 801   using uintX_t = typename ELFT::uint;
 802   raw_ostream &OS =
 803       CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
 804
 805   if (Section.Content || Section.Size) {
 806     SHeader.sh_size = writeContent(OS, Section.Content, Section.Size);
 807     return;
 808   }
 809
 810   for (const ELFYAML::StackSizeEntry &E : *Section.Entries) {
 811     support::endian::write<uintX_t>(OS, E.Address, ELFT::TargetEndianness);
 812     SHeader.sh_size += sizeof(uintX_t) + encodeULEB128(E.Size, OS);
 813   }
 814 }
 815
 816 template <class ELFT>
 817 void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
 818                                          const ELFYAML::HashSection &Section,
 819                                          ContiguousBlobAccumulator &CBA) {
 820   raw_ostream &OS =
 821       CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
 822
 823   unsigned Link = 0;
 824   if (Section.Link.empty() && SN2I.lookup(".dynsym", Link))
 825     SHeader.sh_link = Link;
 826
 827   if (Section.Content || Section.Size) {
 828     SHeader.sh_size = writeContent(OS, Section.Content, Section.Size);
 829     return;
 830   }
 831
 832   support::endian::write<uint32_t>(OS, Section.Bucket->size(),
 833                                    ELFT::TargetEndianness);
 834   support::endian::write<uint32_t>(OS, Section.Chain->size(),
 835                                    ELFT::TargetEndianness);
 836   for (uint32_t Val : *Section.Bucket)
 837     support::endian::write<uint32_t>(OS, Val, ELFT::TargetEndianness);
 838   for (uint32_t Val : *Section.Chain)
 839     support::endian::write<uint32_t>(OS, Val, ELFT::TargetEndianness);
 840
 841   SHeader.sh_size = (2 + Section.Bucket->size() + Section.Chain->size()) * 4;
 842 }
 843
 844 template <class ELFT>
 845 void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
 846                                          const ELFYAML::VerdefSection &Section,
 847                                          ContiguousBlobAccumulator &CBA) {
 848   typedef typename ELFT::Verdef Elf_Verdef;
 849   typedef typename ELFT::Verdaux Elf_Verdaux;
 850   raw_ostream &OS =
 851       CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
 852
 853   uint64_t AuxCnt = 0;
 854   for (size_t I = 0; I < Section.Entries.size(); ++I) {
 855     const ELFYAML::VerdefEntry &E = Section.Entries[I];
 856
 857     Elf_Verdef VerDef;
 858     VerDef.vd_version = E.Version;
 859     VerDef.vd_flags = E.Flags;
 860     VerDef.vd_ndx = E.VersionNdx;
 861     VerDef.vd_hash = E.Hash;
 862     VerDef.vd_aux = sizeof(Elf_Verdef);
 863     VerDef.vd_cnt = E.VerNames.size();
 864     if (I == Section.Entries.size() - 1)
 865       VerDef.vd_next = 0;
 866     else
 867       VerDef.vd_next =
 868           sizeof(Elf_Verdef) + E.VerNames.size() * sizeof(Elf_Verdaux);
 869     OS.write((const char *)&VerDef, sizeof(Elf_Verdef));
 870
 871     for (size_t J = 0; J < E.VerNames.size(); ++J, ++AuxCnt) {
 872       Elf_Verdaux VernAux;
 873       VernAux.vda_name = DotDynstr.getOffset(E.VerNames[J]);
 874       if (J == E.VerNames.size() - 1)
 875         VernAux.vda_next = 0;
 876       else
 877         VernAux.vda_next = sizeof(Elf_Verdaux);
 878       OS.write((const char *)&VernAux, sizeof(Elf_Verdaux));
 879     }
 880   }
 881
 882   SHeader.sh_size = Section.Entries.size() * sizeof(Elf_Verdef) +
 883                     AuxCnt * sizeof(Elf_Verdaux);
 884   SHeader.sh_info = Section.Info;
 885 }
 886
 887 template <class ELFT>
 888 void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
 889                                          const ELFYAML::VerneedSection &Section,
 890                                          ContiguousBlobAccumulator &CBA) {
 891   typedef typename ELFT::Verneed Elf_Verneed;
 892   typedef typename ELFT::Vernaux Elf_Vernaux;
 893
 894   auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
 895
 896   uint64_t AuxCnt = 0;
 897   for (size_t I = 0; I < Section.VerneedV.size(); ++I) {
 898     const ELFYAML::VerneedEntry &VE = Section.VerneedV[I];
 899
 900     Elf_Verneed VerNeed;
 901     VerNeed.vn_version = VE.Version;
 902     VerNeed.vn_file = DotDynstr.getOffset(VE.File);
 903     if (I == Section.VerneedV.size() - 1)
 904       VerNeed.vn_next = 0;
 905     else
 906       VerNeed.vn_next =
 907           sizeof(Elf_Verneed) + VE.AuxV.size() * sizeof(Elf_Vernaux);
 908     VerNeed.vn_cnt = VE.AuxV.size();
 909     VerNeed.vn_aux = sizeof(Elf_Verneed);
 910     OS.write((const char *)&VerNeed, sizeof(Elf_Verneed));
 911
 912     for (size_t J = 0; J < VE.AuxV.size(); ++J, ++AuxCnt) {
 913       const ELFYAML::VernauxEntry &VAuxE = VE.AuxV[J];
 914
 915       Elf_Vernaux VernAux;
 916       VernAux.vna_hash = VAuxE.Hash;
 917       VernAux.vna_flags = VAuxE.Flags;
 918       VernAux.vna_other = VAuxE.Other;
 919       VernAux.vna_name = DotDynstr.getOffset(VAuxE.Name);
 920       if (J == VE.AuxV.size() - 1)
 921         VernAux.vna_next = 0;
 922       else
 923         VernAux.vna_next = sizeof(Elf_Vernaux);
 924       OS.write((const char *)&VernAux, sizeof(Elf_Vernaux));
 925     }
 926   }
 927
 928   SHeader.sh_size = Section.VerneedV.size() * sizeof(Elf_Verneed) +
 929                     AuxCnt * sizeof(Elf_Vernaux);
 930   SHeader.sh_info = Section.Info;
 931 }
 932
 933 template <class ELFT>
 934 void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
 935                                          const ELFYAML::MipsABIFlags &Section,
 936                                          ContiguousBlobAccumulator &CBA) {
 937   assert(Section.Type == llvm::ELF::SHT_MIPS_ABIFLAGS &&
 938          "Section type is not SHT_MIPS_ABIFLAGS");
 939
 940   object::Elf_Mips_ABIFlags<ELFT> Flags;
 941   zero(Flags);
 942   SHeader.sh_entsize = sizeof(Flags);
 943   SHeader.sh_size = SHeader.sh_entsize;
 944
 945   auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
 946   Flags.version = Section.Version;
 947   Flags.isa_level = Section.ISALevel;
 948   Flags.isa_rev = Section.ISARevision;
 949   Flags.gpr_size = Section.GPRSize;
 950   Flags.cpr1_size = Section.CPR1Size;
 951   Flags.cpr2_size = Section.CPR2Size;
 952   Flags.fp_abi = Section.FpABI;
 953   Flags.isa_ext = Section.ISAExtension;
 954   Flags.ases = Section.ASEs;
 955   Flags.flags1 = Section.Flags1;
 956   Flags.flags2 = Section.Flags2;
 957   OS.write((const char *)&Flags, sizeof(Flags));
 958 }
 959
 960 template <class ELFT>
 961 void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
 962                                          const ELFYAML::DynamicSection &Section,
 963                                          ContiguousBlobAccumulator &CBA) {
 964   typedef typename ELFT::uint uintX_t;
 965
 966   assert(Section.Type == llvm::ELF::SHT_DYNAMIC &&
 967          "Section type is not SHT_DYNAMIC");
 968
 969   if (!Section.Entries.empty() && Section.Content)
 970     reportError("cannot specify both raw content and explicit entries "
 971                 "for dynamic section '" +
 972                 Section.Name + "'");
 973
 974   if (Section.Content)
 975     SHeader.sh_size = Section.Content->binary_size();
 976   else
 977     SHeader.sh_size = 2 * sizeof(uintX_t) * Section.Entries.size();
 978   if (Section.EntSize)
 979     SHeader.sh_entsize = *Section.EntSize;
 980   else
 981     SHeader.sh_entsize = sizeof(Elf_Dyn);
 982
 983   raw_ostream &OS =
 984       CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
 985   for (const ELFYAML::DynamicEntry &DE : Section.Entries) {
 986     support::endian::write<uintX_t>(OS, DE.Tag, ELFT::TargetEndianness);
 987     support::endian::write<uintX_t>(OS, DE.Val, ELFT::TargetEndianness);
 988   }
 989   if (Section.Content)
 990     Section.Content->writeAsBinary(OS);
 991 }
 992
 993 template <class ELFT> void ELFState<ELFT>::buildSectionIndex() {
 994   for (unsigned I = 0, E = Doc.Sections.size(); I != E; ++I) {
 995     StringRef Name = Doc.Sections[I]->Name;
 996     if (Name.empty())
 997       continue;
 998
 999     DotShStrtab.add(ELFYAML::dropUniqueSuffix(Name));
1000     if (!SN2I.addName(Name, I))
1001       reportError("repeated section name: '" + Name +
1002                   "' at YAML section number " + Twine(I));
1003   }
1004
1005   DotShStrtab.finalize();
1006 }
1007
1008 template <class ELFT> void ELFState<ELFT>::buildSymbolIndexes() {
1009   auto Build = [this](ArrayRef<ELFYAML::Symbol> V, NameToIdxMap &Map) {
1010     for (size_t I = 0, S = V.size(); I < S; ++I) {
1011       const ELFYAML::Symbol &Sym = V[I];
1012       if (!Sym.Name.empty() && !Map.addName(Sym.Name, I + 1))
1013         reportError("repeated symbol name: '" + Sym.Name + "'");
1014     }
1015   };
1016
1017   Build(Doc.Symbols, SymN2I);
1018   Build(Doc.DynamicSymbols, DynSymN2I);
1019 }
1020
1021 template <class ELFT> void ELFState<ELFT>::finalizeStrings() {
1022   // Add the regular symbol names to .strtab section.
1023   for (const ELFYAML::Symbol &Sym : Doc.Symbols)
1024     DotStrtab.add(ELFYAML::dropUniqueSuffix(Sym.Name));
1025   DotStrtab.finalize();
1026
1027   // Add the dynamic symbol names to .dynstr section.
1028   for (const ELFYAML::Symbol &Sym : Doc.DynamicSymbols)
1029     DotDynstr.add(ELFYAML::dropUniqueSuffix(Sym.Name));
1030
1031   // SHT_GNU_verdef and SHT_GNU_verneed sections might also
1032   // add strings to .dynstr section.
1033   for (const std::unique_ptr<ELFYAML::Section> &Sec : Doc.Sections) {
1034     if (auto VerNeed = dyn_cast<ELFYAML::VerneedSection>(Sec.get())) {
1035       for (const ELFYAML::VerneedEntry &VE : VerNeed->VerneedV) {
1036         DotDynstr.add(VE.File);
1037         for (const ELFYAML::VernauxEntry &Aux : VE.AuxV)
1038           DotDynstr.add(Aux.Name);
1039       }
1040     } else if (auto VerDef = dyn_cast<ELFYAML::VerdefSection>(Sec.get())) {
1041       for (const ELFYAML::VerdefEntry &E : VerDef->Entries)
1042         for (StringRef Name : E.VerNames)
1043           DotDynstr.add(Name);
1044     }
1045   }
1046
1047   DotDynstr.finalize();
1048 }
1049
1050 template <class ELFT>
1051 bool ELFState<ELFT>::writeELF(raw_ostream &OS, ELFYAML::Object &Doc,
1052                               yaml::ErrorHandler EH) {
1053   ELFState<ELFT> State(Doc, EH);
1054
1055   // Finalize .strtab and .dynstr sections. We do that early because want to
1056   // finalize the string table builders before writing the content of the
1057   // sections that might want to use them.
1058   State.finalizeStrings();
1059
1060   State.buildSectionIndex();
1061   State.buildSymbolIndexes();
1062
1063   std::vector<Elf_Phdr> PHeaders;
1064   State.initProgramHeaders(PHeaders);
1065
1066   // XXX: This offset is tightly coupled with the order that we write
1067   // things to `OS`.
1068   const size_t SectionContentBeginOffset =
1069       sizeof(Elf_Ehdr) + sizeof(Elf_Phdr) * Doc.ProgramHeaders.size();
1070   ContiguousBlobAccumulator CBA(SectionContentBeginOffset);
1071
1072   std::vector<Elf_Shdr> SHeaders;
1073   State.initSectionHeaders(SHeaders, CBA);
1074
1075   // Now we can decide segment offsets
1076   State.setProgramHeaderLayout(PHeaders, SHeaders);
1077
1078   if (State.HasError)
1079     return false;
1080
1081   State.writeELFHeader(CBA, OS);
1082   writeArrayData(OS, makeArrayRef(PHeaders));
1083   CBA.writeBlobToStream(OS);
1084   writeArrayData(OS, makeArrayRef(SHeaders));
1085   return true;
1086 }
1087
1088 namespace llvm {
1089 namespace yaml {
1090
1091 bool yaml2elf(llvm::ELFYAML::Object &Doc, raw_ostream &Out, ErrorHandler EH) {
1092   bool IsLE = Doc.Header.Data == ELFYAML::ELF_ELFDATA(ELF::ELFDATA2LSB);
1093   bool Is64Bit = Doc.Header.Class == ELFYAML::ELF_ELFCLASS(ELF::ELFCLASS64);
1094   if (Is64Bit) {
1095     if (IsLE)
1096       return ELFState<object::ELF64LE>::writeELF(Out, Doc, EH);
1097     return ELFState<object::ELF64BE>::writeELF(Out, Doc, EH);
1098   }
1099   if (IsLE)
1100     return ELFState<object::ELF32LE>::writeELF(Out, Doc, EH);
1101   return ELFState<object::ELF32BE>::writeELF(Out, Doc, EH);
1102 }
1103
1104 } // namespace yaml
1105 } // namespace llvm