tools/yaml2obj/yaml2coff.cpp

   1 //===- yaml2coff - Convert YAML to a COFF 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 COFF component of yaml2obj.
  11 ///
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "yaml2obj.h"
  15 #include "llvm/ADT/STLExtras.h"
  16 #include "llvm/ADT/StringExtras.h"
  17 #include "llvm/ADT/StringMap.h"
  18 #include "llvm/ADT/StringSwitch.h"
  19 #include "llvm/DebugInfo/CodeView/DebugStringTableSubsection.h"
  20 #include "llvm/DebugInfo/CodeView/StringsAndChecksums.h"
  21 #include "llvm/Object/COFF.h"
  22 #include "llvm/ObjectYAML/ObjectYAML.h"
  23 #include "llvm/Support/Endian.h"
  24 #include "llvm/Support/MemoryBuffer.h"
  25 #include "llvm/Support/SourceMgr.h"
  26 #include "llvm/Support/WithColor.h"
  27 #include "llvm/Support/raw_ostream.h"
  28 #include <vector>
  29
  30 using namespace llvm;
  31
  32 /// This parses a yaml stream that represents a COFF object file.
  33 /// See docs/yaml2obj for the yaml scheema.
  34 struct COFFParser {
  35   COFFParser(COFFYAML::Object &Obj)
  36       : Obj(Obj), SectionTableStart(0), SectionTableSize(0) {
  37     // A COFF string table always starts with a 4 byte size field. Offsets into
  38     // it include this size, so allocate it now.
  39     StringTable.append(4, char(0));
  40   }
  41
  42   bool useBigObj() const {
  43     return static_cast<int32_t>(Obj.Sections.size()) >
  44            COFF::MaxNumberOfSections16;
  45   }
  46
  47   bool isPE() const { return Obj.OptionalHeader.hasValue(); }
  48   bool is64Bit() const {
  49     return Obj.Header.Machine == COFF::IMAGE_FILE_MACHINE_AMD64 ||
  50            Obj.Header.Machine == COFF::IMAGE_FILE_MACHINE_ARM64;
  51   }
  52
  53   uint32_t getFileAlignment() const {
  54     return Obj.OptionalHeader->Header.FileAlignment;
  55   }
  56
  57   unsigned getHeaderSize() const {
  58     return useBigObj() ? COFF::Header32Size : COFF::Header16Size;
  59   }
  60
  61   unsigned getSymbolSize() const {
  62     return useBigObj() ? COFF::Symbol32Size : COFF::Symbol16Size;
  63   }
  64
  65   bool parseSections() {
  66     for (std::vector<COFFYAML::Section>::iterator i = Obj.Sections.begin(),
  67            e = Obj.Sections.end(); i != e; ++i) {
  68       COFFYAML::Section &Sec = *i;
  69
  70       // If the name is less than 8 bytes, store it in place, otherwise
  71       // store it in the string table.
  72       StringRef Name = Sec.Name;
  73
  74       if (Name.size() <= COFF::NameSize) {
  75         std::copy(Name.begin(), Name.end(), Sec.Header.Name);
  76       } else {
  77         // Add string to the string table and format the index for output.
  78         unsigned Index = getStringIndex(Name);
  79         std::string str = utostr(Index);
  80         if (str.size() > 7) {
  81           errs() << "String table got too large\n";
  82           return false;
  83         }
  84         Sec.Header.Name[0] = '/';
  85         std::copy(str.begin(), str.end(), Sec.Header.Name + 1);
  86       }
  87
  88       if (Sec.Alignment) {
  89         if (Sec.Alignment > 8192) {
  90           errs() << "Section alignment is too large\n";
  91           return false;
  92         }
  93         if (!isPowerOf2_32(Sec.Alignment)) {
  94           errs() << "Section alignment is not a power of 2\n";
  95           return false;
  96         }
  97         Sec.Header.Characteristics |= (Log2_32(Sec.Alignment) + 1) << 20;
  98       }
  99     }
 100     return true;
 101   }
 102
 103   bool parseSymbols() {
 104     for (std::vector<COFFYAML::Symbol>::iterator i = Obj.Symbols.begin(),
 105            e = Obj.Symbols.end(); i != e; ++i) {
 106       COFFYAML::Symbol &Sym = *i;
 107
 108       // If the name is less than 8 bytes, store it in place, otherwise
 109       // store it in the string table.
 110       StringRef Name = Sym.Name;
 111       if (Name.size() <= COFF::NameSize) {
 112         std::copy(Name.begin(), Name.end(), Sym.Header.Name);
 113       } else {
 114         // Add string to the string table and format the index for output.
 115         unsigned Index = getStringIndex(Name);
 116         *reinterpret_cast<support::aligned_ulittle32_t*>(
 117             Sym.Header.Name + 4) = Index;
 118       }
 119
 120       Sym.Header.Type = Sym.SimpleType;
 121       Sym.Header.Type |= Sym.ComplexType << COFF::SCT_COMPLEX_TYPE_SHIFT;
 122     }
 123     return true;
 124   }
 125
 126   bool parse() {
 127     if (!parseSections())
 128       return false;
 129     if (!parseSymbols())
 130       return false;
 131     return true;
 132   }
 133
 134   unsigned getStringIndex(StringRef Str) {
 135     StringMap<unsigned>::iterator i = StringTableMap.find(Str);
 136     if (i == StringTableMap.end()) {
 137       unsigned Index = StringTable.size();
 138       StringTable.append(Str.begin(), Str.end());
 139       StringTable.push_back(0);
 140       StringTableMap[Str] = Index;
 141       return Index;
 142     }
 143     return i->second;
 144   }
 145
 146   COFFYAML::Object &Obj;
 147
 148   codeview::StringsAndChecksums StringsAndChecksums;
 149   BumpPtrAllocator Allocator;
 150   StringMap<unsigned> StringTableMap;
 151   std::string StringTable;
 152   uint32_t SectionTableStart;
 153   uint32_t SectionTableSize;
 154 };
 155
 156 // Take a CP and assign addresses and sizes to everything. Returns false if the
 157 // layout is not valid to do.
 158 static bool layoutOptionalHeader(COFFParser &CP) {
 159   if (!CP.isPE())
 160     return true;
 161   unsigned PEHeaderSize = CP.is64Bit() ? sizeof(object::pe32plus_header)
 162                                        : sizeof(object::pe32_header);
 163   CP.Obj.Header.SizeOfOptionalHeader =
 164       PEHeaderSize +
 165       sizeof(object::data_directory) * (COFF::NUM_DATA_DIRECTORIES + 1);
 166   return true;
 167 }
 168
 169 namespace {
 170 enum { DOSStubSize = 128 };
 171 }
 172
 173 static yaml::BinaryRef
 174 toDebugS(ArrayRef<CodeViewYAML::YAMLDebugSubsection> Subsections,
 175          const codeview::StringsAndChecksums &SC, BumpPtrAllocator &Allocator) {
 176   using namespace codeview;
 177   ExitOnError Err("Error occurred writing .debug$S section");
 178   auto CVSS =
 179       Err(CodeViewYAML::toCodeViewSubsectionList(Allocator, Subsections, SC));
 180
 181   std::vector<DebugSubsectionRecordBuilder> Builders;
 182   uint32_t Size = sizeof(uint32_t);
 183   for (auto &SS : CVSS) {
 184     DebugSubsectionRecordBuilder B(SS, CodeViewContainer::ObjectFile);
 185     Size += B.calculateSerializedLength();
 186     Builders.push_back(std::move(B));
 187   }
 188   uint8_t *Buffer = Allocator.Allocate<uint8_t>(Size);
 189   MutableArrayRef<uint8_t> Output(Buffer, Size);
 190   BinaryStreamWriter Writer(Output, support::little);
 191
 192   Err(Writer.writeInteger<uint32_t>(COFF::DEBUG_SECTION_MAGIC));
 193   for (const auto &B : Builders) {
 194     Err(B.commit(Writer));
 195   }
 196   return {Output};
 197 }
 198
 199 // Take a CP and assign addresses and sizes to everything. Returns false if the
 200 // layout is not valid to do.
 201 static bool layoutCOFF(COFFParser &CP) {
 202   // The section table starts immediately after the header, including the
 203   // optional header.
 204   CP.SectionTableStart =
 205       CP.getHeaderSize() + CP.Obj.Header.SizeOfOptionalHeader;
 206   if (CP.isPE())
 207     CP.SectionTableStart += DOSStubSize + sizeof(COFF::PEMagic);
 208   CP.SectionTableSize = COFF::SectionSize * CP.Obj.Sections.size();
 209
 210   uint32_t CurrentSectionDataOffset =
 211       CP.SectionTableStart + CP.SectionTableSize;
 212
 213   for (COFFYAML::Section &S : CP.Obj.Sections) {
 214     // We support specifying exactly one of SectionData or Subsections.  So if
 215     // there is already some SectionData, then we don't need to do any of this.
 216     if (S.Name == ".debug$S" && S.SectionData.binary_size() == 0) {
 217       CodeViewYAML::initializeStringsAndChecksums(S.DebugS,
 218                                                   CP.StringsAndChecksums);
 219       if (CP.StringsAndChecksums.hasChecksums() &&
 220           CP.StringsAndChecksums.hasStrings())
 221         break;
 222     }
 223   }
 224
 225   // Assign each section data address consecutively.
 226   for (COFFYAML::Section &S : CP.Obj.Sections) {
 227     if (S.Name == ".debug$S") {
 228       if (S.SectionData.binary_size() == 0) {
 229         assert(CP.StringsAndChecksums.hasStrings() &&
 230                "Object file does not have debug string table!");
 231
 232         S.SectionData =
 233             toDebugS(S.DebugS, CP.StringsAndChecksums, CP.Allocator);
 234       }
 235     } else if (S.Name == ".debug$T") {
 236       if (S.SectionData.binary_size() == 0)
 237         S.SectionData = CodeViewYAML::toDebugT(S.DebugT, CP.Allocator, S.Name);
 238     } else if (S.Name == ".debug$P") {
 239       if (S.SectionData.binary_size() == 0)
 240         S.SectionData = CodeViewYAML::toDebugT(S.DebugP, CP.Allocator, S.Name);
 241     } else if (S.Name == ".debug$H") {
 242       if (S.DebugH.hasValue() && S.SectionData.binary_size() == 0)
 243         S.SectionData = CodeViewYAML::toDebugH(*S.DebugH, CP.Allocator);
 244     }
 245
 246     if (S.SectionData.binary_size() > 0) {
 247       CurrentSectionDataOffset = alignTo(CurrentSectionDataOffset,
 248                                          CP.isPE() ? CP.getFileAlignment() : 4);
 249       S.Header.SizeOfRawData = S.SectionData.binary_size();
 250       if (CP.isPE())
 251         S.Header.SizeOfRawData =
 252             alignTo(S.Header.SizeOfRawData, CP.getFileAlignment());
 253       S.Header.PointerToRawData = CurrentSectionDataOffset;
 254       CurrentSectionDataOffset += S.Header.SizeOfRawData;
 255       if (!S.Relocations.empty()) {
 256         S.Header.PointerToRelocations = CurrentSectionDataOffset;
 257         S.Header.NumberOfRelocations = S.Relocations.size();
 258         CurrentSectionDataOffset +=
 259             S.Header.NumberOfRelocations * COFF::RelocationSize;
 260       }
 261     } else {
 262       // Leave SizeOfRawData unaltered. For .bss sections in object files, it
 263       // carries the section size.
 264       S.Header.PointerToRawData = 0;
 265     }
 266   }
 267
 268   uint32_t SymbolTableStart = CurrentSectionDataOffset;
 269
 270   // Calculate number of symbols.
 271   uint32_t NumberOfSymbols = 0;
 272   for (std::vector<COFFYAML::Symbol>::iterator i = CP.Obj.Symbols.begin(),
 273                                                e = CP.Obj.Symbols.end();
 274                                                i != e; ++i) {
 275     uint32_t NumberOfAuxSymbols = 0;
 276     if (i->FunctionDefinition)
 277       NumberOfAuxSymbols += 1;
 278     if (i->bfAndefSymbol)
 279       NumberOfAuxSymbols += 1;
 280     if (i->WeakExternal)
 281       NumberOfAuxSymbols += 1;
 282     if (!i->File.empty())
 283       NumberOfAuxSymbols +=
 284           (i->File.size() + CP.getSymbolSize() - 1) / CP.getSymbolSize();
 285     if (i->SectionDefinition)
 286       NumberOfAuxSymbols += 1;
 287     if (i->CLRToken)
 288       NumberOfAuxSymbols += 1;
 289     i->Header.NumberOfAuxSymbols = NumberOfAuxSymbols;
 290     NumberOfSymbols += 1 + NumberOfAuxSymbols;
 291   }
 292
 293   // Store all the allocated start addresses in the header.
 294   CP.Obj.Header.NumberOfSections = CP.Obj.Sections.size();
 295   CP.Obj.Header.NumberOfSymbols = NumberOfSymbols;
 296   if (NumberOfSymbols > 0 || CP.StringTable.size() > 4)
 297     CP.Obj.Header.PointerToSymbolTable = SymbolTableStart;
 298   else
 299     CP.Obj.Header.PointerToSymbolTable = 0;
 300
 301   *reinterpret_cast<support::ulittle32_t *>(&CP.StringTable[0])
 302     = CP.StringTable.size();
 303
 304   return true;
 305 }
 306
 307 template <typename value_type>
 308 struct binary_le_impl {
 309   value_type Value;
 310   binary_le_impl(value_type V) : Value(V) {}
 311 };
 312
 313 template <typename value_type>
 314 raw_ostream &operator <<( raw_ostream &OS
 315                         , const binary_le_impl<value_type> &BLE) {
 316   char Buffer[sizeof(BLE.Value)];
 317   support::endian::write<value_type, support::little, support::unaligned>(
 318     Buffer, BLE.Value);
 319   OS.write(Buffer, sizeof(BLE.Value));
 320   return OS;
 321 }
 322
 323 template <typename value_type>
 324 binary_le_impl<value_type> binary_le(value_type V) {
 325   return binary_le_impl<value_type>(V);
 326 }
 327
 328 template <size_t NumBytes> struct zeros_impl {};
 329
 330 template <size_t NumBytes>
 331 raw_ostream &operator<<(raw_ostream &OS, const zeros_impl<NumBytes> &) {
 332   char Buffer[NumBytes];
 333   memset(Buffer, 0, sizeof(Buffer));
 334   OS.write(Buffer, sizeof(Buffer));
 335   return OS;
 336 }
 337
 338 template <typename T>
 339 zeros_impl<sizeof(T)> zeros(const T &) {
 340   return zeros_impl<sizeof(T)>();
 341 }
 342
 343 template <typename T>
 344 static uint32_t initializeOptionalHeader(COFFParser &CP, uint16_t Magic, T Header) {
 345   memset(Header, 0, sizeof(*Header));
 346   Header->Magic = Magic;
 347   Header->SectionAlignment = CP.Obj.OptionalHeader->Header.SectionAlignment;
 348   Header->FileAlignment = CP.Obj.OptionalHeader->Header.FileAlignment;
 349   uint32_t SizeOfCode = 0, SizeOfInitializedData = 0,
 350            SizeOfUninitializedData = 0;
 351   uint32_t SizeOfHeaders = alignTo(CP.SectionTableStart + CP.SectionTableSize,
 352                                    Header->FileAlignment);
 353   uint32_t SizeOfImage = alignTo(SizeOfHeaders, Header->SectionAlignment);
 354   uint32_t BaseOfData = 0;
 355   for (const COFFYAML::Section &S : CP.Obj.Sections) {
 356     if (S.Header.Characteristics & COFF::IMAGE_SCN_CNT_CODE)
 357       SizeOfCode += S.Header.SizeOfRawData;
 358     if (S.Header.Characteristics & COFF::IMAGE_SCN_CNT_INITIALIZED_DATA)
 359       SizeOfInitializedData += S.Header.SizeOfRawData;
 360     if (S.Header.Characteristics & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA)
 361       SizeOfUninitializedData += S.Header.SizeOfRawData;
 362     if (S.Name.equals(".text"))
 363       Header->BaseOfCode = S.Header.VirtualAddress; // RVA
 364     else if (S.Name.equals(".data"))
 365       BaseOfData = S.Header.VirtualAddress; // RVA
 366     if (S.Header.VirtualAddress)
 367       SizeOfImage += alignTo(S.Header.VirtualSize, Header->SectionAlignment);
 368   }
 369   Header->SizeOfCode = SizeOfCode;
 370   Header->SizeOfInitializedData = SizeOfInitializedData;
 371   Header->SizeOfUninitializedData = SizeOfUninitializedData;
 372   Header->AddressOfEntryPoint =
 373       CP.Obj.OptionalHeader->Header.AddressOfEntryPoint; // RVA
 374   Header->ImageBase = CP.Obj.OptionalHeader->Header.ImageBase;
 375   Header->MajorOperatingSystemVersion =
 376       CP.Obj.OptionalHeader->Header.MajorOperatingSystemVersion;
 377   Header->MinorOperatingSystemVersion =
 378       CP.Obj.OptionalHeader->Header.MinorOperatingSystemVersion;
 379   Header->MajorImageVersion =
 380       CP.Obj.OptionalHeader->Header.MajorImageVersion;
 381   Header->MinorImageVersion =
 382       CP.Obj.OptionalHeader->Header.MinorImageVersion;
 383   Header->MajorSubsystemVersion =
 384       CP.Obj.OptionalHeader->Header.MajorSubsystemVersion;
 385   Header->MinorSubsystemVersion =
 386       CP.Obj.OptionalHeader->Header.MinorSubsystemVersion;
 387   Header->SizeOfImage = SizeOfImage;
 388   Header->SizeOfHeaders = SizeOfHeaders;
 389   Header->Subsystem = CP.Obj.OptionalHeader->Header.Subsystem;
 390   Header->DLLCharacteristics = CP.Obj.OptionalHeader->Header.DLLCharacteristics;
 391   Header->SizeOfStackReserve = CP.Obj.OptionalHeader->Header.SizeOfStackReserve;
 392   Header->SizeOfStackCommit = CP.Obj.OptionalHeader->Header.SizeOfStackCommit;
 393   Header->SizeOfHeapReserve = CP.Obj.OptionalHeader->Header.SizeOfHeapReserve;
 394   Header->SizeOfHeapCommit = CP.Obj.OptionalHeader->Header.SizeOfHeapCommit;
 395   Header->NumberOfRvaAndSize = COFF::NUM_DATA_DIRECTORIES + 1;
 396   return BaseOfData;
 397 }
 398
 399 static bool writeCOFF(COFFParser &CP, raw_ostream &OS) {
 400   if (CP.isPE()) {
 401     // PE files start with a DOS stub.
 402     object::dos_header DH;
 403     memset(&DH, 0, sizeof(DH));
 404
 405     // DOS EXEs start with "MZ" magic.
 406     DH.Magic[0] = 'M';
 407     DH.Magic[1] = 'Z';
 408     // Initializing the AddressOfRelocationTable is strictly optional but
 409     // mollifies certain tools which expect it to have a value greater than
 410     // 0x40.
 411     DH.AddressOfRelocationTable = sizeof(DH);
 412     // This is the address of the PE signature.
 413     DH.AddressOfNewExeHeader = DOSStubSize;
 414
 415     // Write out our DOS stub.
 416     OS.write(reinterpret_cast<char *>(&DH), sizeof(DH));
 417     // Write padding until we reach the position of where our PE signature
 418     // should live.
 419     OS.write_zeros(DOSStubSize - sizeof(DH));
 420     // Write out the PE signature.
 421     OS.write(COFF::PEMagic, sizeof(COFF::PEMagic));
 422   }
 423   if (CP.useBigObj()) {
 424     OS << binary_le(static_cast<uint16_t>(COFF::IMAGE_FILE_MACHINE_UNKNOWN))
 425        << binary_le(static_cast<uint16_t>(0xffff))
 426        << binary_le(static_cast<uint16_t>(COFF::BigObjHeader::MinBigObjectVersion))
 427        << binary_le(CP.Obj.Header.Machine)
 428        << binary_le(CP.Obj.Header.TimeDateStamp);
 429     OS.write(COFF::BigObjMagic, sizeof(COFF::BigObjMagic));
 430     OS << zeros(uint32_t(0))
 431        << zeros(uint32_t(0))
 432        << zeros(uint32_t(0))
 433        << zeros(uint32_t(0))
 434        << binary_le(CP.Obj.Header.NumberOfSections)
 435        << binary_le(CP.Obj.Header.PointerToSymbolTable)
 436        << binary_le(CP.Obj.Header.NumberOfSymbols);
 437   } else {
 438     OS << binary_le(CP.Obj.Header.Machine)
 439        << binary_le(static_cast<int16_t>(CP.Obj.Header.NumberOfSections))
 440        << binary_le(CP.Obj.Header.TimeDateStamp)
 441        << binary_le(CP.Obj.Header.PointerToSymbolTable)
 442        << binary_le(CP.Obj.Header.NumberOfSymbols)
 443        << binary_le(CP.Obj.Header.SizeOfOptionalHeader)
 444        << binary_le(CP.Obj.Header.Characteristics);
 445   }
 446   if (CP.isPE()) {
 447     if (CP.is64Bit()) {
 448       object::pe32plus_header PEH;
 449       initializeOptionalHeader(CP, COFF::PE32Header::PE32_PLUS, &PEH);
 450       OS.write(reinterpret_cast<char *>(&PEH), sizeof(PEH));
 451     } else {
 452       object::pe32_header PEH;
 453       uint32_t BaseOfData = initializeOptionalHeader(CP, COFF::PE32Header::PE32, &PEH);
 454       PEH.BaseOfData = BaseOfData;
 455       OS.write(reinterpret_cast<char *>(&PEH), sizeof(PEH));
 456     }
 457     for (const Optional<COFF::DataDirectory> &DD :
 458          CP.Obj.OptionalHeader->DataDirectories) {
 459       if (!DD.hasValue()) {
 460         OS << zeros(uint32_t(0));
 461         OS << zeros(uint32_t(0));
 462       } else {
 463         OS << binary_le(DD->RelativeVirtualAddress);
 464         OS << binary_le(DD->Size);
 465       }
 466     }
 467     OS << zeros(uint32_t(0));
 468     OS << zeros(uint32_t(0));
 469   }
 470
 471   assert(OS.tell() == CP.SectionTableStart);
 472   // Output section table.
 473   for (std::vector<COFFYAML::Section>::iterator i = CP.Obj.Sections.begin(),
 474                                                 e = CP.Obj.Sections.end();
 475                                                 i != e; ++i) {
 476     OS.write(i->Header.Name, COFF::NameSize);
 477     OS << binary_le(i->Header.VirtualSize)
 478        << binary_le(i->Header.VirtualAddress)
 479        << binary_le(i->Header.SizeOfRawData)
 480        << binary_le(i->Header.PointerToRawData)
 481        << binary_le(i->Header.PointerToRelocations)
 482        << binary_le(i->Header.PointerToLineNumbers)
 483        << binary_le(i->Header.NumberOfRelocations)
 484        << binary_le(i->Header.NumberOfLineNumbers)
 485        << binary_le(i->Header.Characteristics);
 486   }
 487   assert(OS.tell() == CP.SectionTableStart + CP.SectionTableSize);
 488
 489   unsigned CurSymbol = 0;
 490   StringMap<unsigned> SymbolTableIndexMap;
 491   for (std::vector<COFFYAML::Symbol>::iterator I = CP.Obj.Symbols.begin(),
 492                                                E = CP.Obj.Symbols.end();
 493        I != E; ++I) {
 494     SymbolTableIndexMap[I->Name] = CurSymbol;
 495     CurSymbol += 1 + I->Header.NumberOfAuxSymbols;
 496   }
 497
 498   // Output section data.
 499   for (const COFFYAML::Section &S : CP.Obj.Sections) {
 500     if (S.Header.SizeOfRawData == 0 || S.Header.PointerToRawData == 0)
 501       continue;
 502     assert(S.Header.PointerToRawData >= OS.tell());
 503     OS.write_zeros(S.Header.PointerToRawData - OS.tell());
 504     S.SectionData.writeAsBinary(OS);
 505     assert(S.Header.SizeOfRawData >= S.SectionData.binary_size());
 506     OS.write_zeros(S.Header.SizeOfRawData - S.SectionData.binary_size());
 507     for (const COFFYAML::Relocation &R : S.Relocations) {
 508       uint32_t SymbolTableIndex;
 509       if (R.SymbolTableIndex) {
 510         if (!R.SymbolName.empty())
 511           WithColor::error()
 512               << "Both SymbolName and SymbolTableIndex specified\n";
 513         SymbolTableIndex = *R.SymbolTableIndex;
 514       } else {
 515         SymbolTableIndex = SymbolTableIndexMap[R.SymbolName];
 516       }
 517       OS << binary_le(R.VirtualAddress)
 518          << binary_le(SymbolTableIndex)
 519          << binary_le(R.Type);
 520     }
 521   }
 522
 523   // Output symbol table.
 524
 525   for (std::vector<COFFYAML::Symbol>::const_iterator i = CP.Obj.Symbols.begin(),
 526                                                      e = CP.Obj.Symbols.end();
 527                                                      i != e; ++i) {
 528     OS.write(i->Header.Name, COFF::NameSize);
 529     OS << binary_le(i->Header.Value);
 530     if (CP.useBigObj())
 531        OS << binary_le(i->Header.SectionNumber);
 532     else
 533        OS << binary_le(static_cast<int16_t>(i->Header.SectionNumber));
 534     OS << binary_le(i->Header.Type)
 535        << binary_le(i->Header.StorageClass)
 536        << binary_le(i->Header.NumberOfAuxSymbols);
 537
 538     if (i->FunctionDefinition) {
 539       OS << binary_le(i->FunctionDefinition->TagIndex)
 540          << binary_le(i->FunctionDefinition->TotalSize)
 541          << binary_le(i->FunctionDefinition->PointerToLinenumber)
 542          << binary_le(i->FunctionDefinition->PointerToNextFunction)
 543          << zeros(i->FunctionDefinition->unused);
 544       OS.write_zeros(CP.getSymbolSize() - COFF::Symbol16Size);
 545     }
 546     if (i->bfAndefSymbol) {
 547       OS << zeros(i->bfAndefSymbol->unused1)
 548          << binary_le(i->bfAndefSymbol->Linenumber)
 549          << zeros(i->bfAndefSymbol->unused2)
 550          << binary_le(i->bfAndefSymbol->PointerToNextFunction)
 551          << zeros(i->bfAndefSymbol->unused3);
 552       OS.write_zeros(CP.getSymbolSize() - COFF::Symbol16Size);
 553     }
 554     if (i->WeakExternal) {
 555       OS << binary_le(i->WeakExternal->TagIndex)
 556          << binary_le(i->WeakExternal->Characteristics)
 557          << zeros(i->WeakExternal->unused);
 558       OS.write_zeros(CP.getSymbolSize() - COFF::Symbol16Size);
 559     }
 560     if (!i->File.empty()) {
 561       unsigned SymbolSize = CP.getSymbolSize();
 562       uint32_t NumberOfAuxRecords =
 563           (i->File.size() + SymbolSize - 1) / SymbolSize;
 564       uint32_t NumberOfAuxBytes = NumberOfAuxRecords * SymbolSize;
 565       uint32_t NumZeros = NumberOfAuxBytes - i->File.size();
 566       OS.write(i->File.data(), i->File.size());
 567       OS.write_zeros(NumZeros);
 568     }
 569     if (i->SectionDefinition) {
 570       OS << binary_le(i->SectionDefinition->Length)
 571          << binary_le(i->SectionDefinition->NumberOfRelocations)
 572          << binary_le(i->SectionDefinition->NumberOfLinenumbers)
 573          << binary_le(i->SectionDefinition->CheckSum)
 574          << binary_le(static_cast<int16_t>(i->SectionDefinition->Number))
 575          << binary_le(i->SectionDefinition->Selection)
 576          << zeros(i->SectionDefinition->unused)
 577          << binary_le(static_cast<int16_t>(i->SectionDefinition->Number >> 16));
 578       OS.write_zeros(CP.getSymbolSize() - COFF::Symbol16Size);
 579     }
 580     if (i->CLRToken) {
 581       OS << binary_le(i->CLRToken->AuxType)
 582          << zeros(i->CLRToken->unused1)
 583          << binary_le(i->CLRToken->SymbolTableIndex)
 584          << zeros(i->CLRToken->unused2);
 585       OS.write_zeros(CP.getSymbolSize() - COFF::Symbol16Size);
 586     }
 587   }
 588
 589   // Output string table.
 590   if (CP.Obj.Header.PointerToSymbolTable)
 591     OS.write(&CP.StringTable[0], CP.StringTable.size());
 592   return true;
 593 }
 594
 595 int yaml2coff(llvm::COFFYAML::Object &Doc, raw_ostream &Out) {
 596   COFFParser CP(Doc);
 597   if (!CP.parse()) {
 598     errs() << "yaml2obj: Failed to parse YAML file!\n";
 599     return 1;
 600   }
 601
 602   if (!layoutOptionalHeader(CP)) {
 603     errs() << "yaml2obj: Failed to layout optional header for COFF file!\n";
 604     return 1;
 605   }
 606
 607   if (!layoutCOFF(CP)) {
 608     errs() << "yaml2obj: Failed to layout COFF file!\n";
 609     return 1;
 610   }
 611   if (!writeCOFF(CP, Out)) {
 612     errs() << "yaml2obj: Failed to write COFF file!\n";
 613     return 1;
 614   }
 615   return 0;
 616 }