contrib/llvm-project/llvm/lib/ObjectYAML/COFFEmitter.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 "llvm/ADT/STLExtras.h"
  15 #include "llvm/ADT/StringExtras.h"
  16 #include "llvm/ADT/StringMap.h"
  17 #include "llvm/ADT/StringSwitch.h"
  18 #include "llvm/DebugInfo/CodeView/DebugStringTableSubsection.h"
  19 #include "llvm/DebugInfo/CodeView/StringsAndChecksums.h"
  20 #include "llvm/Object/COFF.h"
  21 #include "llvm/ObjectYAML/ObjectYAML.h"
  22 #include "llvm/ObjectYAML/yaml2obj.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 namespace {
  33
  34 /// This parses a yaml stream that represents a COFF object file.
  35 /// See docs/yaml2obj for the yaml scheema.
  36 struct COFFParser {
  37   COFFParser(COFFYAML::Object &Obj, yaml::ErrorHandler EH)
  38       : Obj(Obj), SectionTableStart(0), SectionTableSize(0), ErrHandler(EH) {
  39     // A COFF string table always starts with a 4 byte size field. Offsets into
  40     // it include this size, so allocate it now.
  41     StringTable.append(4, char(0));
  42   }
  43
  44   bool useBigObj() const {
  45     return static_cast<int32_t>(Obj.Sections.size()) >
  46            COFF::MaxNumberOfSections16;
  47   }
  48
  49   bool isPE() const { return Obj.OptionalHeader.hasValue(); }
  50   bool is64Bit() const {
  51     return Obj.Header.Machine == COFF::IMAGE_FILE_MACHINE_AMD64 ||
  52            Obj.Header.Machine == COFF::IMAGE_FILE_MACHINE_ARM64;
  53   }
  54
  55   uint32_t getFileAlignment() const {
  56     return Obj.OptionalHeader->Header.FileAlignment;
  57   }
  58
  59   unsigned getHeaderSize() const {
  60     return useBigObj() ? COFF::Header32Size : COFF::Header16Size;
  61   }
  62
  63   unsigned getSymbolSize() const {
  64     return useBigObj() ? COFF::Symbol32Size : COFF::Symbol16Size;
  65   }
  66
  67   bool parseSections() {
  68     for (std::vector<COFFYAML::Section>::iterator i = Obj.Sections.begin(),
  69                                                   e = Obj.Sections.end();
  70          i != e; ++i) {
  71       COFFYAML::Section &Sec = *i;
  72
  73       // If the name is less than 8 bytes, store it in place, otherwise
  74       // store it in the string table.
  75       StringRef Name = Sec.Name;
  76
  77       if (Name.size() <= COFF::NameSize) {
  78         std::copy(Name.begin(), Name.end(), Sec.Header.Name);
  79       } else {
  80         // Add string to the string table and format the index for output.
  81         unsigned Index = getStringIndex(Name);
  82         std::string str = utostr(Index);
  83         if (str.size() > 7) {
  84           ErrHandler("string table got too large");
  85           return false;
  86         }
  87         Sec.Header.Name[0] = '/';
  88         std::copy(str.begin(), str.end(), Sec.Header.Name + 1);
  89       }
  90
  91       if (Sec.Alignment) {
  92         if (Sec.Alignment > 8192) {
  93           ErrHandler("section alignment is too large");
  94           return false;
  95         }
  96         if (!isPowerOf2_32(Sec.Alignment)) {
  97           ErrHandler("section alignment is not a power of 2");
  98           return false;
  99         }
 100         Sec.Header.Characteristics |= (Log2_32(Sec.Alignment) + 1) << 20;
 101       }
 102     }
 103     return true;
 104   }
 105
 106   bool parseSymbols() {
 107     for (std::vector<COFFYAML::Symbol>::iterator i = Obj.Symbols.begin(),
 108                                                  e = Obj.Symbols.end();
 109          i != e; ++i) {
 110       COFFYAML::Symbol &Sym = *i;
 111
 112       // If the name is less than 8 bytes, store it in place, otherwise
 113       // store it in the string table.
 114       StringRef Name = Sym.Name;
 115       if (Name.size() <= COFF::NameSize) {
 116         std::copy(Name.begin(), Name.end(), Sym.Header.Name);
 117       } else {
 118         // Add string to the string table and format the index for output.
 119         unsigned Index = getStringIndex(Name);
 120         *reinterpret_cast<support::aligned_ulittle32_t *>(Sym.Header.Name + 4) =
 121             Index;
 122       }
 123
 124       Sym.Header.Type = Sym.SimpleType;
 125       Sym.Header.Type |= Sym.ComplexType << COFF::SCT_COMPLEX_TYPE_SHIFT;
 126     }
 127     return true;
 128   }
 129
 130   bool parse() {
 131     if (!parseSections())
 132       return false;
 133     if (!parseSymbols())
 134       return false;
 135     return true;
 136   }
 137
 138   unsigned getStringIndex(StringRef Str) {
 139     StringMap<unsigned>::iterator i = StringTableMap.find(Str);
 140     if (i == StringTableMap.end()) {
 141       unsigned Index = StringTable.size();
 142       StringTable.append(Str.begin(), Str.end());
 143       StringTable.push_back(0);
 144       StringTableMap[Str] = Index;
 145       return Index;
 146     }
 147     return i->second;
 148   }
 149
 150   COFFYAML::Object &Obj;
 151
 152   codeview::StringsAndChecksums StringsAndChecksums;
 153   BumpPtrAllocator Allocator;
 154   StringMap<unsigned> StringTableMap;
 155   std::string StringTable;
 156   uint32_t SectionTableStart;
 157   uint32_t SectionTableSize;
 158
 159   yaml::ErrorHandler ErrHandler;
 160 };
 161
 162 enum { DOSStubSize = 128 };
 163
 164 } // end anonymous namespace
 165
 166 // Take a CP and assign addresses and sizes to everything. Returns false if the
 167 // layout is not valid to do.
 168 static bool layoutOptionalHeader(COFFParser &CP) {
 169   if (!CP.isPE())
 170     return true;
 171   unsigned PEHeaderSize = CP.is64Bit() ? sizeof(object::pe32plus_header)
 172                                        : sizeof(object::pe32_header);
 173   CP.Obj.Header.SizeOfOptionalHeader =
 174       PEHeaderSize +
 175       sizeof(object::data_directory) * (COFF::NUM_DATA_DIRECTORIES + 1);
 176   return true;
 177 }
 178
 179 static yaml::BinaryRef
 180 toDebugS(ArrayRef<CodeViewYAML::YAMLDebugSubsection> Subsections,
 181          const codeview::StringsAndChecksums &SC, BumpPtrAllocator &Allocator) {
 182   using namespace codeview;
 183   ExitOnError Err("Error occurred writing .debug$S section");
 184   auto CVSS =
 185       Err(CodeViewYAML::toCodeViewSubsectionList(Allocator, Subsections, SC));
 186
 187   std::vector<DebugSubsectionRecordBuilder> Builders;
 188   uint32_t Size = sizeof(uint32_t);
 189   for (auto &SS : CVSS) {
 190     DebugSubsectionRecordBuilder B(SS, CodeViewContainer::ObjectFile);
 191     Size += B.calculateSerializedLength();
 192     Builders.push_back(std::move(B));
 193   }
 194   uint8_t *Buffer = Allocator.Allocate<uint8_t>(Size);
 195   MutableArrayRef<uint8_t> Output(Buffer, Size);
 196   BinaryStreamWriter Writer(Output, support::little);
 197
 198   Err(Writer.writeInteger<uint32_t>(COFF::DEBUG_SECTION_MAGIC));
 199   for (const auto &B : Builders) {
 200     Err(B.commit(Writer));
 201   }
 202   return {Output};
 203 }
 204
 205 // Take a CP and assign addresses and sizes to everything. Returns false if the
 206 // layout is not valid to do.
 207 static bool layoutCOFF(COFFParser &CP) {
 208   // The section table starts immediately after the header, including the
 209   // optional header.
 210   CP.SectionTableStart =
 211       CP.getHeaderSize() + CP.Obj.Header.SizeOfOptionalHeader;
 212   if (CP.isPE())
 213     CP.SectionTableStart += DOSStubSize + sizeof(COFF::PEMagic);
 214   CP.SectionTableSize = COFF::SectionSize * CP.Obj.Sections.size();
 215
 216   uint32_t CurrentSectionDataOffset =
 217       CP.SectionTableStart + CP.SectionTableSize;
 218
 219   for (COFFYAML::Section &S : CP.Obj.Sections) {
 220     // We support specifying exactly one of SectionData or Subsections.  So if
 221     // there is already some SectionData, then we don't need to do any of this.
 222     if (S.Name == ".debug$S" && S.SectionData.binary_size() == 0) {
 223       CodeViewYAML::initializeStringsAndChecksums(S.DebugS,
 224                                                   CP.StringsAndChecksums);
 225       if (CP.StringsAndChecksums.hasChecksums() &&
 226           CP.StringsAndChecksums.hasStrings())
 227         break;
 228     }
 229   }
 230
 231   // Assign each section data address consecutively.
 232   for (COFFYAML::Section &S : CP.Obj.Sections) {
 233     if (S.Name == ".debug$S") {
 234       if (S.SectionData.binary_size() == 0) {
 235         assert(CP.StringsAndChecksums.hasStrings() &&
 236                "Object file does not have debug string table!");
 237
 238         S.SectionData =
 239             toDebugS(S.DebugS, CP.StringsAndChecksums, CP.Allocator);
 240       }
 241     } else if (S.Name == ".debug$T") {
 242       if (S.SectionData.binary_size() == 0)
 243         S.SectionData = CodeViewYAML::toDebugT(S.DebugT, CP.Allocator, S.Name);
 244     } else if (S.Name == ".debug$P") {
 245       if (S.SectionData.binary_size() == 0)
 246         S.SectionData = CodeViewYAML::toDebugT(S.DebugP, CP.Allocator, S.Name);
 247     } else if (S.Name == ".debug$H") {
 248       if (S.DebugH.hasValue() && S.SectionData.binary_size() == 0)
 249         S.SectionData = CodeViewYAML::toDebugH(*S.DebugH, CP.Allocator);
 250     }
 251
 252     if (S.SectionData.binary_size() > 0) {
 253       CurrentSectionDataOffset = alignTo(CurrentSectionDataOffset,
 254                                          CP.isPE() ? CP.getFileAlignment() : 4);
 255       S.Header.SizeOfRawData = S.SectionData.binary_size();
 256       if (CP.isPE())
 257         S.Header.SizeOfRawData =
 258             alignTo(S.Header.SizeOfRawData, CP.getFileAlignment());
 259       S.Header.PointerToRawData = CurrentSectionDataOffset;
 260       CurrentSectionDataOffset += S.Header.SizeOfRawData;
 261       if (!S.Relocations.empty()) {
 262         S.Header.PointerToRelocations = CurrentSectionDataOffset;
 263         if (S.Header.Characteristics & COFF::IMAGE_SCN_LNK_NRELOC_OVFL) {
 264           S.Header.NumberOfRelocations = 0xffff;
 265           CurrentSectionDataOffset += COFF::RelocationSize;
 266         } else
 267           S.Header.NumberOfRelocations = S.Relocations.size();
 268         CurrentSectionDataOffset += S.Relocations.size() * COFF::RelocationSize;
 269       }
 270     } else {
 271       // Leave SizeOfRawData unaltered. For .bss sections in object files, it
 272       // carries the section size.
 273       S.Header.PointerToRawData = 0;
 274     }
 275   }
 276
 277   uint32_t SymbolTableStart = CurrentSectionDataOffset;
 278
 279   // Calculate number of symbols.
 280   uint32_t NumberOfSymbols = 0;
 281   for (std::vector<COFFYAML::Symbol>::iterator i = CP.Obj.Symbols.begin(),
 282                                                e = CP.Obj.Symbols.end();
 283        i != e; ++i) {
 284     uint32_t NumberOfAuxSymbols = 0;
 285     if (i->FunctionDefinition)
 286       NumberOfAuxSymbols += 1;
 287     if (i->bfAndefSymbol)
 288       NumberOfAuxSymbols += 1;
 289     if (i->WeakExternal)
 290       NumberOfAuxSymbols += 1;
 291     if (!i->File.empty())
 292       NumberOfAuxSymbols +=
 293           (i->File.size() + CP.getSymbolSize() - 1) / CP.getSymbolSize();
 294     if (i->SectionDefinition)
 295       NumberOfAuxSymbols += 1;
 296     if (i->CLRToken)
 297       NumberOfAuxSymbols += 1;
 298     i->Header.NumberOfAuxSymbols = NumberOfAuxSymbols;
 299     NumberOfSymbols += 1 + NumberOfAuxSymbols;
 300   }
 301
 302   // Store all the allocated start addresses in the header.
 303   CP.Obj.Header.NumberOfSections = CP.Obj.Sections.size();
 304   CP.Obj.Header.NumberOfSymbols = NumberOfSymbols;
 305   if (NumberOfSymbols > 0 || CP.StringTable.size() > 4)
 306     CP.Obj.Header.PointerToSymbolTable = SymbolTableStart;
 307   else
 308     CP.Obj.Header.PointerToSymbolTable = 0;
 309
 310   *reinterpret_cast<support::ulittle32_t *>(&CP.StringTable[0]) =
 311       CP.StringTable.size();
 312
 313   return true;
 314 }
 315
 316 template <typename value_type> struct binary_le_impl {
 317   value_type Value;
 318   binary_le_impl(value_type V) : Value(V) {}
 319 };
 320
 321 template <typename value_type>
 322 raw_ostream &operator<<(raw_ostream &OS,
 323                         const binary_le_impl<value_type> &BLE) {
 324   char Buffer[sizeof(BLE.Value)];
 325   support::endian::write<value_type, support::little, support::unaligned>(
 326       Buffer, BLE.Value);
 327   OS.write(Buffer, sizeof(BLE.Value));
 328   return OS;
 329 }
 330
 331 template <typename value_type>
 332 binary_le_impl<value_type> binary_le(value_type V) {
 333   return binary_le_impl<value_type>(V);
 334 }
 335
 336 template <size_t NumBytes> struct zeros_impl {};
 337
 338 template <size_t NumBytes>
 339 raw_ostream &operator<<(raw_ostream &OS, const zeros_impl<NumBytes> &) {
 340   char Buffer[NumBytes];
 341   memset(Buffer, 0, sizeof(Buffer));
 342   OS.write(Buffer, sizeof(Buffer));
 343   return OS;
 344 }
 345
 346 template <typename T> zeros_impl<sizeof(T)> zeros(const T &) {
 347   return zeros_impl<sizeof(T)>();
 348 }
 349
 350 template <typename T>
 351 static uint32_t initializeOptionalHeader(COFFParser &CP, uint16_t Magic,
 352                                          T Header) {
 353   memset(Header, 0, sizeof(*Header));
 354   Header->Magic = Magic;
 355   Header->SectionAlignment = CP.Obj.OptionalHeader->Header.SectionAlignment;
 356   Header->FileAlignment = CP.Obj.OptionalHeader->Header.FileAlignment;
 357   uint32_t SizeOfCode = 0, SizeOfInitializedData = 0,
 358            SizeOfUninitializedData = 0;
 359   uint32_t SizeOfHeaders = alignTo(CP.SectionTableStart + CP.SectionTableSize,
 360                                    Header->FileAlignment);
 361   uint32_t SizeOfImage = alignTo(SizeOfHeaders, Header->SectionAlignment);
 362   uint32_t BaseOfData = 0;
 363   for (const COFFYAML::Section &S : CP.Obj.Sections) {
 364     if (S.Header.Characteristics & COFF::IMAGE_SCN_CNT_CODE)
 365       SizeOfCode += S.Header.SizeOfRawData;
 366     if (S.Header.Characteristics & COFF::IMAGE_SCN_CNT_INITIALIZED_DATA)
 367       SizeOfInitializedData += S.Header.SizeOfRawData;
 368     if (S.Header.Characteristics & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA)
 369       SizeOfUninitializedData += S.Header.SizeOfRawData;
 370     if (S.Name.equals(".text"))
 371       Header->BaseOfCode = S.Header.VirtualAddress; // RVA
 372     else if (S.Name.equals(".data"))
 373       BaseOfData = S.Header.VirtualAddress; // RVA
 374     if (S.Header.VirtualAddress)
 375       SizeOfImage += alignTo(S.Header.VirtualSize, Header->SectionAlignment);
 376   }
 377   Header->SizeOfCode = SizeOfCode;
 378   Header->SizeOfInitializedData = SizeOfInitializedData;
 379   Header->SizeOfUninitializedData = SizeOfUninitializedData;
 380   Header->AddressOfEntryPoint =
 381       CP.Obj.OptionalHeader->Header.AddressOfEntryPoint; // RVA
 382   Header->ImageBase = CP.Obj.OptionalHeader->Header.ImageBase;
 383   Header->MajorOperatingSystemVersion =
 384       CP.Obj.OptionalHeader->Header.MajorOperatingSystemVersion;
 385   Header->MinorOperatingSystemVersion =
 386       CP.Obj.OptionalHeader->Header.MinorOperatingSystemVersion;
 387   Header->MajorImageVersion = CP.Obj.OptionalHeader->Header.MajorImageVersion;
 388   Header->MinorImageVersion = CP.Obj.OptionalHeader->Header.MinorImageVersion;
 389   Header->MajorSubsystemVersion =
 390       CP.Obj.OptionalHeader->Header.MajorSubsystemVersion;
 391   Header->MinorSubsystemVersion =
 392       CP.Obj.OptionalHeader->Header.MinorSubsystemVersion;
 393   Header->SizeOfImage = SizeOfImage;
 394   Header->SizeOfHeaders = SizeOfHeaders;
 395   Header->Subsystem = CP.Obj.OptionalHeader->Header.Subsystem;
 396   Header->DLLCharacteristics = CP.Obj.OptionalHeader->Header.DLLCharacteristics;
 397   Header->SizeOfStackReserve = CP.Obj.OptionalHeader->Header.SizeOfStackReserve;
 398   Header->SizeOfStackCommit = CP.Obj.OptionalHeader->Header.SizeOfStackCommit;
 399   Header->SizeOfHeapReserve = CP.Obj.OptionalHeader->Header.SizeOfHeapReserve;
 400   Header->SizeOfHeapCommit = CP.Obj.OptionalHeader->Header.SizeOfHeapCommit;
 401   Header->NumberOfRvaAndSize = COFF::NUM_DATA_DIRECTORIES + 1;
 402   return BaseOfData;
 403 }
 404
 405 static bool writeCOFF(COFFParser &CP, raw_ostream &OS) {
 406   if (CP.isPE()) {
 407     // PE files start with a DOS stub.
 408     object::dos_header DH;
 409     memset(&DH, 0, sizeof(DH));
 410
 411     // DOS EXEs start with "MZ" magic.
 412     DH.Magic[0] = 'M';
 413     DH.Magic[1] = 'Z';
 414     // Initializing the AddressOfRelocationTable is strictly optional but
 415     // mollifies certain tools which expect it to have a value greater than
 416     // 0x40.
 417     DH.AddressOfRelocationTable = sizeof(DH);
 418     // This is the address of the PE signature.
 419     DH.AddressOfNewExeHeader = DOSStubSize;
 420
 421     // Write out our DOS stub.
 422     OS.write(reinterpret_cast<char *>(&DH), sizeof(DH));
 423     // Write padding until we reach the position of where our PE signature
 424     // should live.
 425     OS.write_zeros(DOSStubSize - sizeof(DH));
 426     // Write out the PE signature.
 427     OS.write(COFF::PEMagic, sizeof(COFF::PEMagic));
 428   }
 429   if (CP.useBigObj()) {
 430     OS << binary_le(static_cast<uint16_t>(COFF::IMAGE_FILE_MACHINE_UNKNOWN))
 431        << binary_le(static_cast<uint16_t>(0xffff))
 432        << binary_le(
 433               static_cast<uint16_t>(COFF::BigObjHeader::MinBigObjectVersion))
 434        << binary_le(CP.Obj.Header.Machine)
 435        << binary_le(CP.Obj.Header.TimeDateStamp);
 436     OS.write(COFF::BigObjMagic, sizeof(COFF::BigObjMagic));
 437     OS << zeros(uint32_t(0)) << zeros(uint32_t(0)) << zeros(uint32_t(0))
 438        << zeros(uint32_t(0)) << binary_le(CP.Obj.Header.NumberOfSections)
 439        << binary_le(CP.Obj.Header.PointerToSymbolTable)
 440        << binary_le(CP.Obj.Header.NumberOfSymbols);
 441   } else {
 442     OS << binary_le(CP.Obj.Header.Machine)
 443        << binary_le(static_cast<int16_t>(CP.Obj.Header.NumberOfSections))
 444        << binary_le(CP.Obj.Header.TimeDateStamp)
 445        << binary_le(CP.Obj.Header.PointerToSymbolTable)
 446        << binary_le(CP.Obj.Header.NumberOfSymbols)
 447        << binary_le(CP.Obj.Header.SizeOfOptionalHeader)
 448        << binary_le(CP.Obj.Header.Characteristics);
 449   }
 450   if (CP.isPE()) {
 451     if (CP.is64Bit()) {
 452       object::pe32plus_header PEH;
 453       initializeOptionalHeader(CP, COFF::PE32Header::PE32_PLUS, &PEH);
 454       OS.write(reinterpret_cast<char *>(&PEH), sizeof(PEH));
 455     } else {
 456       object::pe32_header PEH;
 457       uint32_t BaseOfData =
 458           initializeOptionalHeader(CP, COFF::PE32Header::PE32, &PEH);
 459       PEH.BaseOfData = BaseOfData;
 460       OS.write(reinterpret_cast<char *>(&PEH), sizeof(PEH));
 461     }
 462     for (const Optional<COFF::DataDirectory> &DD :
 463          CP.Obj.OptionalHeader->DataDirectories) {
 464       if (!DD.hasValue()) {
 465         OS << zeros(uint32_t(0));
 466         OS << zeros(uint32_t(0));
 467       } else {
 468         OS << binary_le(DD->RelativeVirtualAddress);
 469         OS << binary_le(DD->Size);
 470       }
 471     }
 472     OS << zeros(uint32_t(0));
 473     OS << zeros(uint32_t(0));
 474   }
 475
 476   assert(OS.tell() == CP.SectionTableStart);
 477   // Output section table.
 478   for (std::vector<COFFYAML::Section>::iterator i = CP.Obj.Sections.begin(),
 479                                                 e = CP.Obj.Sections.end();
 480        i != e; ++i) {
 481     OS.write(i->Header.Name, COFF::NameSize);
 482     OS << binary_le(i->Header.VirtualSize)
 483        << binary_le(i->Header.VirtualAddress)
 484        << binary_le(i->Header.SizeOfRawData)
 485        << binary_le(i->Header.PointerToRawData)
 486        << binary_le(i->Header.PointerToRelocations)
 487        << binary_le(i->Header.PointerToLineNumbers)
 488        << binary_le(i->Header.NumberOfRelocations)
 489        << binary_le(i->Header.NumberOfLineNumbers)
 490        << binary_le(i->Header.Characteristics);
 491   }
 492   assert(OS.tell() == CP.SectionTableStart + CP.SectionTableSize);
 493
 494   unsigned CurSymbol = 0;
 495   StringMap<unsigned> SymbolTableIndexMap;
 496   for (std::vector<COFFYAML::Symbol>::iterator I = CP.Obj.Symbols.begin(),
 497                                                E = CP.Obj.Symbols.end();
 498        I != E; ++I) {
 499     SymbolTableIndexMap[I->Name] = CurSymbol;
 500     CurSymbol += 1 + I->Header.NumberOfAuxSymbols;
 501   }
 502
 503   // Output section data.
 504   for (const COFFYAML::Section &S : CP.Obj.Sections) {
 505     if (S.Header.SizeOfRawData == 0 || S.Header.PointerToRawData == 0)
 506       continue;
 507     assert(S.Header.PointerToRawData >= OS.tell());
 508     OS.write_zeros(S.Header.PointerToRawData - OS.tell());
 509     S.SectionData.writeAsBinary(OS);
 510     assert(S.Header.SizeOfRawData >= S.SectionData.binary_size());
 511     OS.write_zeros(S.Header.SizeOfRawData - S.SectionData.binary_size());
 512     if (S.Header.Characteristics & COFF::IMAGE_SCN_LNK_NRELOC_OVFL)
 513       OS << binary_le<uint32_t>(/*VirtualAddress=*/ S.Relocations.size() + 1)
 514          << binary_le<uint32_t>(/*SymbolTableIndex=*/ 0)
 515          << binary_le<uint16_t>(/*Type=*/ 0);
 516     for (const COFFYAML::Relocation &R : S.Relocations) {
 517       uint32_t SymbolTableIndex;
 518       if (R.SymbolTableIndex) {
 519         if (!R.SymbolName.empty())
 520           WithColor::error()
 521               << "Both SymbolName and SymbolTableIndex specified\n";
 522         SymbolTableIndex = *R.SymbolTableIndex;
 523       } else {
 524         SymbolTableIndex = SymbolTableIndexMap[R.SymbolName];
 525       }
 526       OS << binary_le(R.VirtualAddress) << binary_le(SymbolTableIndex)
 527          << binary_le(R.Type);
 528     }
 529   }
 530
 531   // Output symbol table.
 532
 533   for (std::vector<COFFYAML::Symbol>::const_iterator i = CP.Obj.Symbols.begin(),
 534                                                      e = CP.Obj.Symbols.end();
 535        i != e; ++i) {
 536     OS.write(i->Header.Name, COFF::NameSize);
 537     OS << binary_le(i->Header.Value);
 538     if (CP.useBigObj())
 539       OS << binary_le(i->Header.SectionNumber);
 540     else
 541       OS << binary_le(static_cast<int16_t>(i->Header.SectionNumber));
 542     OS << binary_le(i->Header.Type) << binary_le(i->Header.StorageClass)
 543        << binary_le(i->Header.NumberOfAuxSymbols);
 544
 545     if (i->FunctionDefinition) {
 546       OS << binary_le(i->FunctionDefinition->TagIndex)
 547          << binary_le(i->FunctionDefinition->TotalSize)
 548          << binary_le(i->FunctionDefinition->PointerToLinenumber)
 549          << binary_le(i->FunctionDefinition->PointerToNextFunction)
 550          << zeros(i->FunctionDefinition->unused);
 551       OS.write_zeros(CP.getSymbolSize() - COFF::Symbol16Size);
 552     }
 553     if (i->bfAndefSymbol) {
 554       OS << zeros(i->bfAndefSymbol->unused1)
 555          << binary_le(i->bfAndefSymbol->Linenumber)
 556          << zeros(i->bfAndefSymbol->unused2)
 557          << binary_le(i->bfAndefSymbol->PointerToNextFunction)
 558          << zeros(i->bfAndefSymbol->unused3);
 559       OS.write_zeros(CP.getSymbolSize() - COFF::Symbol16Size);
 560     }
 561     if (i->WeakExternal) {
 562       OS << binary_le(i->WeakExternal->TagIndex)
 563          << binary_le(i->WeakExternal->Characteristics)
 564          << zeros(i->WeakExternal->unused);
 565       OS.write_zeros(CP.getSymbolSize() - COFF::Symbol16Size);
 566     }
 567     if (!i->File.empty()) {
 568       unsigned SymbolSize = CP.getSymbolSize();
 569       uint32_t NumberOfAuxRecords =
 570           (i->File.size() + SymbolSize - 1) / SymbolSize;
 571       uint32_t NumberOfAuxBytes = NumberOfAuxRecords * SymbolSize;
 572       uint32_t NumZeros = NumberOfAuxBytes - i->File.size();
 573       OS.write(i->File.data(), i->File.size());
 574       OS.write_zeros(NumZeros);
 575     }
 576     if (i->SectionDefinition) {
 577       OS << binary_le(i->SectionDefinition->Length)
 578          << binary_le(i->SectionDefinition->NumberOfRelocations)
 579          << binary_le(i->SectionDefinition->NumberOfLinenumbers)
 580          << binary_le(i->SectionDefinition->CheckSum)
 581          << binary_le(static_cast<int16_t>(i->SectionDefinition->Number))
 582          << binary_le(i->SectionDefinition->Selection)
 583          << zeros(i->SectionDefinition->unused)
 584          << binary_le(static_cast<int16_t>(i->SectionDefinition->Number >> 16));
 585       OS.write_zeros(CP.getSymbolSize() - COFF::Symbol16Size);
 586     }
 587     if (i->CLRToken) {
 588       OS << binary_le(i->CLRToken->AuxType) << zeros(i->CLRToken->unused1)
 589          << binary_le(i->CLRToken->SymbolTableIndex)
 590          << zeros(i->CLRToken->unused2);
 591       OS.write_zeros(CP.getSymbolSize() - COFF::Symbol16Size);
 592     }
 593   }
 594
 595   // Output string table.
 596   if (CP.Obj.Header.PointerToSymbolTable)
 597     OS.write(&CP.StringTable[0], CP.StringTable.size());
 598   return true;
 599 }
 600
 601 namespace llvm {
 602 namespace yaml {
 603
 604 bool yaml2coff(llvm::COFFYAML::Object &Doc, raw_ostream &Out,
 605                ErrorHandler ErrHandler) {
 606   COFFParser CP(Doc, ErrHandler);
 607   if (!CP.parse()) {
 608     ErrHandler("failed to parse YAML file");
 609     return false;
 610   }
 611
 612   if (!layoutOptionalHeader(CP)) {
 613     ErrHandler("failed to layout optional header for COFF file");
 614     return false;
 615   }
 616
 617   if (!layoutCOFF(CP)) {
 618     ErrHandler("failed to layout COFF file");
 619     return false;
 620   }
 621   if (!writeCOFF(CP, Out)) {
 622     ErrHandler("failed to write COFF file");
 623     return false;
 624   }
 625   return true;
 626 }
 627
 628 } // namespace yaml
 629 } // namespace llvm