diff --git a/llvm/lib/ObjectYAML/COFFEmitter.cpp b/llvm/lib/ObjectYAML/COFFEmitter.cpp
new file mode 100644
index 0000000..d94cdbf
--- /dev/null
+++ b/llvm/lib/ObjectYAML/COFFEmitter.cpp
@@ -0,0 +1,619 @@
+//===- yaml2coff - Convert YAML to a COFF object file ---------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// The COFF component of yaml2obj.
+///
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/DebugInfo/CodeView/DebugStringTableSubsection.h"
+#include "llvm/DebugInfo/CodeView/StringsAndChecksums.h"
+#include "llvm/Object/COFF.h"
+#include "llvm/ObjectYAML/ObjectYAML.h"
+#include "llvm/ObjectYAML/yaml2obj.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/WithColor.h"
+#include "llvm/Support/raw_ostream.h"
+#include <vector>
+
+using namespace llvm;
+
+namespace {
+
+/// This parses a yaml stream that represents a COFF object file.
+/// See docs/yaml2obj for the yaml scheema.
+struct COFFParser {
+  COFFParser(COFFYAML::Object &Obj)
+      : Obj(Obj), SectionTableStart(0), SectionTableSize(0) {
+    // A COFF string table always starts with a 4 byte size field. Offsets into
+    // it include this size, so allocate it now.
+    StringTable.append(4, char(0));
+  }
+
+  bool useBigObj() const {
+    return static_cast<int32_t>(Obj.Sections.size()) >
+           COFF::MaxNumberOfSections16;
+  }
+
+  bool isPE() const { return Obj.OptionalHeader.hasValue(); }
+  bool is64Bit() const {
+    return Obj.Header.Machine == COFF::IMAGE_FILE_MACHINE_AMD64 ||
+           Obj.Header.Machine == COFF::IMAGE_FILE_MACHINE_ARM64;
+  }
+
+  uint32_t getFileAlignment() const {
+    return Obj.OptionalHeader->Header.FileAlignment;
+  }
+
+  unsigned getHeaderSize() const {
+    return useBigObj() ? COFF::Header32Size : COFF::Header16Size;
+  }
+
+  unsigned getSymbolSize() const {
+    return useBigObj() ? COFF::Symbol32Size : COFF::Symbol16Size;
+  }
+
+  bool parseSections() {
+    for (std::vector<COFFYAML::Section>::iterator i = Obj.Sections.begin(),
+                                                  e = Obj.Sections.end();
+         i != e; ++i) {
+      COFFYAML::Section &Sec = *i;
+
+      // If the name is less than 8 bytes, store it in place, otherwise
+      // store it in the string table.
+      StringRef Name = Sec.Name;
+
+      if (Name.size() <= COFF::NameSize) {
+        std::copy(Name.begin(), Name.end(), Sec.Header.Name);
+      } else {
+        // Add string to the string table and format the index for output.
+        unsigned Index = getStringIndex(Name);
+        std::string str = utostr(Index);
+        if (str.size() > 7) {
+          errs() << "String table got too large\n";
+          return false;
+        }
+        Sec.Header.Name[0] = '/';
+        std::copy(str.begin(), str.end(), Sec.Header.Name + 1);
+      }
+
+      if (Sec.Alignment) {
+        if (Sec.Alignment > 8192) {
+          errs() << "Section alignment is too large\n";
+          return false;
+        }
+        if (!isPowerOf2_32(Sec.Alignment)) {
+          errs() << "Section alignment is not a power of 2\n";
+          return false;
+        }
+        Sec.Header.Characteristics |= (Log2_32(Sec.Alignment) + 1) << 20;
+      }
+    }
+    return true;
+  }
+
+  bool parseSymbols() {
+    for (std::vector<COFFYAML::Symbol>::iterator i = Obj.Symbols.begin(),
+                                                 e = Obj.Symbols.end();
+         i != e; ++i) {
+      COFFYAML::Symbol &Sym = *i;
+
+      // If the name is less than 8 bytes, store it in place, otherwise
+      // store it in the string table.
+      StringRef Name = Sym.Name;
+      if (Name.size() <= COFF::NameSize) {
+        std::copy(Name.begin(), Name.end(), Sym.Header.Name);
+      } else {
+        // Add string to the string table and format the index for output.
+        unsigned Index = getStringIndex(Name);
+        *reinterpret_cast<support::aligned_ulittle32_t *>(Sym.Header.Name + 4) =
+            Index;
+      }
+
+      Sym.Header.Type = Sym.SimpleType;
+      Sym.Header.Type |= Sym.ComplexType << COFF::SCT_COMPLEX_TYPE_SHIFT;
+    }
+    return true;
+  }
+
+  bool parse() {
+    if (!parseSections())
+      return false;
+    if (!parseSymbols())
+      return false;
+    return true;
+  }
+
+  unsigned getStringIndex(StringRef Str) {
+    StringMap<unsigned>::iterator i = StringTableMap.find(Str);
+    if (i == StringTableMap.end()) {
+      unsigned Index = StringTable.size();
+      StringTable.append(Str.begin(), Str.end());
+      StringTable.push_back(0);
+      StringTableMap[Str] = Index;
+      return Index;
+    }
+    return i->second;
+  }
+
+  COFFYAML::Object &Obj;
+
+  codeview::StringsAndChecksums StringsAndChecksums;
+  BumpPtrAllocator Allocator;
+  StringMap<unsigned> StringTableMap;
+  std::string StringTable;
+  uint32_t SectionTableStart;
+  uint32_t SectionTableSize;
+};
+
+enum { DOSStubSize = 128 };
+
+} // end anonymous namespace
+
+// Take a CP and assign addresses and sizes to everything. Returns false if the
+// layout is not valid to do.
+static bool layoutOptionalHeader(COFFParser &CP) {
+  if (!CP.isPE())
+    return true;
+  unsigned PEHeaderSize = CP.is64Bit() ? sizeof(object::pe32plus_header)
+                                       : sizeof(object::pe32_header);
+  CP.Obj.Header.SizeOfOptionalHeader =
+      PEHeaderSize +
+      sizeof(object::data_directory) * (COFF::NUM_DATA_DIRECTORIES + 1);
+  return true;
+}
+
+static yaml::BinaryRef
+toDebugS(ArrayRef<CodeViewYAML::YAMLDebugSubsection> Subsections,
+         const codeview::StringsAndChecksums &SC, BumpPtrAllocator &Allocator) {
+  using namespace codeview;
+  ExitOnError Err("Error occurred writing .debug$S section");
+  auto CVSS =
+      Err(CodeViewYAML::toCodeViewSubsectionList(Allocator, Subsections, SC));
+
+  std::vector<DebugSubsectionRecordBuilder> Builders;
+  uint32_t Size = sizeof(uint32_t);
+  for (auto &SS : CVSS) {
+    DebugSubsectionRecordBuilder B(SS, CodeViewContainer::ObjectFile);
+    Size += B.calculateSerializedLength();
+    Builders.push_back(std::move(B));
+  }
+  uint8_t *Buffer = Allocator.Allocate<uint8_t>(Size);
+  MutableArrayRef<uint8_t> Output(Buffer, Size);
+  BinaryStreamWriter Writer(Output, support::little);
+
+  Err(Writer.writeInteger<uint32_t>(COFF::DEBUG_SECTION_MAGIC));
+  for (const auto &B : Builders) {
+    Err(B.commit(Writer));
+  }
+  return {Output};
+}
+
+// Take a CP and assign addresses and sizes to everything. Returns false if the
+// layout is not valid to do.
+static bool layoutCOFF(COFFParser &CP) {
+  // The section table starts immediately after the header, including the
+  // optional header.
+  CP.SectionTableStart =
+      CP.getHeaderSize() + CP.Obj.Header.SizeOfOptionalHeader;
+  if (CP.isPE())
+    CP.SectionTableStart += DOSStubSize + sizeof(COFF::PEMagic);
+  CP.SectionTableSize = COFF::SectionSize * CP.Obj.Sections.size();
+
+  uint32_t CurrentSectionDataOffset =
+      CP.SectionTableStart + CP.SectionTableSize;
+
+  for (COFFYAML::Section &S : CP.Obj.Sections) {
+    // We support specifying exactly one of SectionData or Subsections.  So if
+    // there is already some SectionData, then we don't need to do any of this.
+    if (S.Name == ".debug$S" && S.SectionData.binary_size() == 0) {
+      CodeViewYAML::initializeStringsAndChecksums(S.DebugS,
+                                                  CP.StringsAndChecksums);
+      if (CP.StringsAndChecksums.hasChecksums() &&
+          CP.StringsAndChecksums.hasStrings())
+        break;
+    }
+  }
+
+  // Assign each section data address consecutively.
+  for (COFFYAML::Section &S : CP.Obj.Sections) {
+    if (S.Name == ".debug$S") {
+      if (S.SectionData.binary_size() == 0) {
+        assert(CP.StringsAndChecksums.hasStrings() &&
+               "Object file does not have debug string table!");
+
+        S.SectionData =
+            toDebugS(S.DebugS, CP.StringsAndChecksums, CP.Allocator);
+      }
+    } else if (S.Name == ".debug$T") {
+      if (S.SectionData.binary_size() == 0)
+        S.SectionData = CodeViewYAML::toDebugT(S.DebugT, CP.Allocator, S.Name);
+    } else if (S.Name == ".debug$P") {
+      if (S.SectionData.binary_size() == 0)
+        S.SectionData = CodeViewYAML::toDebugT(S.DebugP, CP.Allocator, S.Name);
+    } else if (S.Name == ".debug$H") {
+      if (S.DebugH.hasValue() && S.SectionData.binary_size() == 0)
+        S.SectionData = CodeViewYAML::toDebugH(*S.DebugH, CP.Allocator);
+    }
+
+    if (S.SectionData.binary_size() > 0) {
+      CurrentSectionDataOffset = alignTo(CurrentSectionDataOffset,
+                                         CP.isPE() ? CP.getFileAlignment() : 4);
+      S.Header.SizeOfRawData = S.SectionData.binary_size();
+      if (CP.isPE())
+        S.Header.SizeOfRawData =
+            alignTo(S.Header.SizeOfRawData, CP.getFileAlignment());
+      S.Header.PointerToRawData = CurrentSectionDataOffset;
+      CurrentSectionDataOffset += S.Header.SizeOfRawData;
+      if (!S.Relocations.empty()) {
+        S.Header.PointerToRelocations = CurrentSectionDataOffset;
+        S.Header.NumberOfRelocations = S.Relocations.size();
+        CurrentSectionDataOffset +=
+            S.Header.NumberOfRelocations * COFF::RelocationSize;
+      }
+    } else {
+      // Leave SizeOfRawData unaltered. For .bss sections in object files, it
+      // carries the section size.
+      S.Header.PointerToRawData = 0;
+    }
+  }
+
+  uint32_t SymbolTableStart = CurrentSectionDataOffset;
+
+  // Calculate number of symbols.
+  uint32_t NumberOfSymbols = 0;
+  for (std::vector<COFFYAML::Symbol>::iterator i = CP.Obj.Symbols.begin(),
+                                               e = CP.Obj.Symbols.end();
+       i != e; ++i) {
+    uint32_t NumberOfAuxSymbols = 0;
+    if (i->FunctionDefinition)
+      NumberOfAuxSymbols += 1;
+    if (i->bfAndefSymbol)
+      NumberOfAuxSymbols += 1;
+    if (i->WeakExternal)
+      NumberOfAuxSymbols += 1;
+    if (!i->File.empty())
+      NumberOfAuxSymbols +=
+          (i->File.size() + CP.getSymbolSize() - 1) / CP.getSymbolSize();
+    if (i->SectionDefinition)
+      NumberOfAuxSymbols += 1;
+    if (i->CLRToken)
+      NumberOfAuxSymbols += 1;
+    i->Header.NumberOfAuxSymbols = NumberOfAuxSymbols;
+    NumberOfSymbols += 1 + NumberOfAuxSymbols;
+  }
+
+  // Store all the allocated start addresses in the header.
+  CP.Obj.Header.NumberOfSections = CP.Obj.Sections.size();
+  CP.Obj.Header.NumberOfSymbols = NumberOfSymbols;
+  if (NumberOfSymbols > 0 || CP.StringTable.size() > 4)
+    CP.Obj.Header.PointerToSymbolTable = SymbolTableStart;
+  else
+    CP.Obj.Header.PointerToSymbolTable = 0;
+
+  *reinterpret_cast<support::ulittle32_t *>(&CP.StringTable[0]) =
+      CP.StringTable.size();
+
+  return true;
+}
+
+template <typename value_type> struct binary_le_impl {
+  value_type Value;
+  binary_le_impl(value_type V) : Value(V) {}
+};
+
+template <typename value_type>
+raw_ostream &operator<<(raw_ostream &OS,
+                        const binary_le_impl<value_type> &BLE) {
+  char Buffer[sizeof(BLE.Value)];
+  support::endian::write<value_type, support::little, support::unaligned>(
+      Buffer, BLE.Value);
+  OS.write(Buffer, sizeof(BLE.Value));
+  return OS;
+}
+
+template <typename value_type>
+binary_le_impl<value_type> binary_le(value_type V) {
+  return binary_le_impl<value_type>(V);
+}
+
+template <size_t NumBytes> struct zeros_impl {};
+
+template <size_t NumBytes>
+raw_ostream &operator<<(raw_ostream &OS, const zeros_impl<NumBytes> &) {
+  char Buffer[NumBytes];
+  memset(Buffer, 0, sizeof(Buffer));
+  OS.write(Buffer, sizeof(Buffer));
+  return OS;
+}
+
+template <typename T> zeros_impl<sizeof(T)> zeros(const T &) {
+  return zeros_impl<sizeof(T)>();
+}
+
+template <typename T>
+static uint32_t initializeOptionalHeader(COFFParser &CP, uint16_t Magic,
+                                         T Header) {
+  memset(Header, 0, sizeof(*Header));
+  Header->Magic = Magic;
+  Header->SectionAlignment = CP.Obj.OptionalHeader->Header.SectionAlignment;
+  Header->FileAlignment = CP.Obj.OptionalHeader->Header.FileAlignment;
+  uint32_t SizeOfCode = 0, SizeOfInitializedData = 0,
+           SizeOfUninitializedData = 0;
+  uint32_t SizeOfHeaders = alignTo(CP.SectionTableStart + CP.SectionTableSize,
+                                   Header->FileAlignment);
+  uint32_t SizeOfImage = alignTo(SizeOfHeaders, Header->SectionAlignment);
+  uint32_t BaseOfData = 0;
+  for (const COFFYAML::Section &S : CP.Obj.Sections) {
+    if (S.Header.Characteristics & COFF::IMAGE_SCN_CNT_CODE)
+      SizeOfCode += S.Header.SizeOfRawData;
+    if (S.Header.Characteristics & COFF::IMAGE_SCN_CNT_INITIALIZED_DATA)
+      SizeOfInitializedData += S.Header.SizeOfRawData;
+    if (S.Header.Characteristics & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA)
+      SizeOfUninitializedData += S.Header.SizeOfRawData;
+    if (S.Name.equals(".text"))
+      Header->BaseOfCode = S.Header.VirtualAddress; // RVA
+    else if (S.Name.equals(".data"))
+      BaseOfData = S.Header.VirtualAddress; // RVA
+    if (S.Header.VirtualAddress)
+      SizeOfImage += alignTo(S.Header.VirtualSize, Header->SectionAlignment);
+  }
+  Header->SizeOfCode = SizeOfCode;
+  Header->SizeOfInitializedData = SizeOfInitializedData;
+  Header->SizeOfUninitializedData = SizeOfUninitializedData;
+  Header->AddressOfEntryPoint =
+      CP.Obj.OptionalHeader->Header.AddressOfEntryPoint; // RVA
+  Header->ImageBase = CP.Obj.OptionalHeader->Header.ImageBase;
+  Header->MajorOperatingSystemVersion =
+      CP.Obj.OptionalHeader->Header.MajorOperatingSystemVersion;
+  Header->MinorOperatingSystemVersion =
+      CP.Obj.OptionalHeader->Header.MinorOperatingSystemVersion;
+  Header->MajorImageVersion = CP.Obj.OptionalHeader->Header.MajorImageVersion;
+  Header->MinorImageVersion = CP.Obj.OptionalHeader->Header.MinorImageVersion;
+  Header->MajorSubsystemVersion =
+      CP.Obj.OptionalHeader->Header.MajorSubsystemVersion;
+  Header->MinorSubsystemVersion =
+      CP.Obj.OptionalHeader->Header.MinorSubsystemVersion;
+  Header->SizeOfImage = SizeOfImage;
+  Header->SizeOfHeaders = SizeOfHeaders;
+  Header->Subsystem = CP.Obj.OptionalHeader->Header.Subsystem;
+  Header->DLLCharacteristics = CP.Obj.OptionalHeader->Header.DLLCharacteristics;
+  Header->SizeOfStackReserve = CP.Obj.OptionalHeader->Header.SizeOfStackReserve;
+  Header->SizeOfStackCommit = CP.Obj.OptionalHeader->Header.SizeOfStackCommit;
+  Header->SizeOfHeapReserve = CP.Obj.OptionalHeader->Header.SizeOfHeapReserve;
+  Header->SizeOfHeapCommit = CP.Obj.OptionalHeader->Header.SizeOfHeapCommit;
+  Header->NumberOfRvaAndSize = COFF::NUM_DATA_DIRECTORIES + 1;
+  return BaseOfData;
+}
+
+static bool writeCOFF(COFFParser &CP, raw_ostream &OS) {
+  if (CP.isPE()) {
+    // PE files start with a DOS stub.
+    object::dos_header DH;
+    memset(&DH, 0, sizeof(DH));
+
+    // DOS EXEs start with "MZ" magic.
+    DH.Magic[0] = 'M';
+    DH.Magic[1] = 'Z';
+    // Initializing the AddressOfRelocationTable is strictly optional but
+    // mollifies certain tools which expect it to have a value greater than
+    // 0x40.
+    DH.AddressOfRelocationTable = sizeof(DH);
+    // This is the address of the PE signature.
+    DH.AddressOfNewExeHeader = DOSStubSize;
+
+    // Write out our DOS stub.
+    OS.write(reinterpret_cast<char *>(&DH), sizeof(DH));
+    // Write padding until we reach the position of where our PE signature
+    // should live.
+    OS.write_zeros(DOSStubSize - sizeof(DH));
+    // Write out the PE signature.
+    OS.write(COFF::PEMagic, sizeof(COFF::PEMagic));
+  }
+  if (CP.useBigObj()) {
+    OS << binary_le(static_cast<uint16_t>(COFF::IMAGE_FILE_MACHINE_UNKNOWN))
+       << binary_le(static_cast<uint16_t>(0xffff))
+       << binary_le(
+              static_cast<uint16_t>(COFF::BigObjHeader::MinBigObjectVersion))
+       << binary_le(CP.Obj.Header.Machine)
+       << binary_le(CP.Obj.Header.TimeDateStamp);
+    OS.write(COFF::BigObjMagic, sizeof(COFF::BigObjMagic));
+    OS << zeros(uint32_t(0)) << zeros(uint32_t(0)) << zeros(uint32_t(0))
+       << zeros(uint32_t(0)) << binary_le(CP.Obj.Header.NumberOfSections)
+       << binary_le(CP.Obj.Header.PointerToSymbolTable)
+       << binary_le(CP.Obj.Header.NumberOfSymbols);
+  } else {
+    OS << binary_le(CP.Obj.Header.Machine)
+       << binary_le(static_cast<int16_t>(CP.Obj.Header.NumberOfSections))
+       << binary_le(CP.Obj.Header.TimeDateStamp)
+       << binary_le(CP.Obj.Header.PointerToSymbolTable)
+       << binary_le(CP.Obj.Header.NumberOfSymbols)
+       << binary_le(CP.Obj.Header.SizeOfOptionalHeader)
+       << binary_le(CP.Obj.Header.Characteristics);
+  }
+  if (CP.isPE()) {
+    if (CP.is64Bit()) {
+      object::pe32plus_header PEH;
+      initializeOptionalHeader(CP, COFF::PE32Header::PE32_PLUS, &PEH);
+      OS.write(reinterpret_cast<char *>(&PEH), sizeof(PEH));
+    } else {
+      object::pe32_header PEH;
+      uint32_t BaseOfData =
+          initializeOptionalHeader(CP, COFF::PE32Header::PE32, &PEH);
+      PEH.BaseOfData = BaseOfData;
+      OS.write(reinterpret_cast<char *>(&PEH), sizeof(PEH));
+    }
+    for (const Optional<COFF::DataDirectory> &DD :
+         CP.Obj.OptionalHeader->DataDirectories) {
+      if (!DD.hasValue()) {
+        OS << zeros(uint32_t(0));
+        OS << zeros(uint32_t(0));
+      } else {
+        OS << binary_le(DD->RelativeVirtualAddress);
+        OS << binary_le(DD->Size);
+      }
+    }
+    OS << zeros(uint32_t(0));
+    OS << zeros(uint32_t(0));
+  }
+
+  assert(OS.tell() == CP.SectionTableStart);
+  // Output section table.
+  for (std::vector<COFFYAML::Section>::iterator i = CP.Obj.Sections.begin(),
+                                                e = CP.Obj.Sections.end();
+       i != e; ++i) {
+    OS.write(i->Header.Name, COFF::NameSize);
+    OS << binary_le(i->Header.VirtualSize)
+       << binary_le(i->Header.VirtualAddress)
+       << binary_le(i->Header.SizeOfRawData)
+       << binary_le(i->Header.PointerToRawData)
+       << binary_le(i->Header.PointerToRelocations)
+       << binary_le(i->Header.PointerToLineNumbers)
+       << binary_le(i->Header.NumberOfRelocations)
+       << binary_le(i->Header.NumberOfLineNumbers)
+       << binary_le(i->Header.Characteristics);
+  }
+  assert(OS.tell() == CP.SectionTableStart + CP.SectionTableSize);
+
+  unsigned CurSymbol = 0;
+  StringMap<unsigned> SymbolTableIndexMap;
+  for (std::vector<COFFYAML::Symbol>::iterator I = CP.Obj.Symbols.begin(),
+                                               E = CP.Obj.Symbols.end();
+       I != E; ++I) {
+    SymbolTableIndexMap[I->Name] = CurSymbol;
+    CurSymbol += 1 + I->Header.NumberOfAuxSymbols;
+  }
+
+  // Output section data.
+  for (const COFFYAML::Section &S : CP.Obj.Sections) {
+    if (S.Header.SizeOfRawData == 0 || S.Header.PointerToRawData == 0)
+      continue;
+    assert(S.Header.PointerToRawData >= OS.tell());
+    OS.write_zeros(S.Header.PointerToRawData - OS.tell());
+    S.SectionData.writeAsBinary(OS);
+    assert(S.Header.SizeOfRawData >= S.SectionData.binary_size());
+    OS.write_zeros(S.Header.SizeOfRawData - S.SectionData.binary_size());
+    for (const COFFYAML::Relocation &R : S.Relocations) {
+      uint32_t SymbolTableIndex;
+      if (R.SymbolTableIndex) {
+        if (!R.SymbolName.empty())
+          WithColor::error()
+              << "Both SymbolName and SymbolTableIndex specified\n";
+        SymbolTableIndex = *R.SymbolTableIndex;
+      } else {
+        SymbolTableIndex = SymbolTableIndexMap[R.SymbolName];
+      }
+      OS << binary_le(R.VirtualAddress) << binary_le(SymbolTableIndex)
+         << binary_le(R.Type);
+    }
+  }
+
+  // Output symbol table.
+
+  for (std::vector<COFFYAML::Symbol>::const_iterator i = CP.Obj.Symbols.begin(),
+                                                     e = CP.Obj.Symbols.end();
+       i != e; ++i) {
+    OS.write(i->Header.Name, COFF::NameSize);
+    OS << binary_le(i->Header.Value);
+    if (CP.useBigObj())
+      OS << binary_le(i->Header.SectionNumber);
+    else
+      OS << binary_le(static_cast<int16_t>(i->Header.SectionNumber));
+    OS << binary_le(i->Header.Type) << binary_le(i->Header.StorageClass)
+       << binary_le(i->Header.NumberOfAuxSymbols);
+
+    if (i->FunctionDefinition) {
+      OS << binary_le(i->FunctionDefinition->TagIndex)
+         << binary_le(i->FunctionDefinition->TotalSize)
+         << binary_le(i->FunctionDefinition->PointerToLinenumber)
+         << binary_le(i->FunctionDefinition->PointerToNextFunction)
+         << zeros(i->FunctionDefinition->unused);
+      OS.write_zeros(CP.getSymbolSize() - COFF::Symbol16Size);
+    }
+    if (i->bfAndefSymbol) {
+      OS << zeros(i->bfAndefSymbol->unused1)
+         << binary_le(i->bfAndefSymbol->Linenumber)
+         << zeros(i->bfAndefSymbol->unused2)
+         << binary_le(i->bfAndefSymbol->PointerToNextFunction)
+         << zeros(i->bfAndefSymbol->unused3);
+      OS.write_zeros(CP.getSymbolSize() - COFF::Symbol16Size);
+    }
+    if (i->WeakExternal) {
+      OS << binary_le(i->WeakExternal->TagIndex)
+         << binary_le(i->WeakExternal->Characteristics)
+         << zeros(i->WeakExternal->unused);
+      OS.write_zeros(CP.getSymbolSize() - COFF::Symbol16Size);
+    }
+    if (!i->File.empty()) {
+      unsigned SymbolSize = CP.getSymbolSize();
+      uint32_t NumberOfAuxRecords =
+          (i->File.size() + SymbolSize - 1) / SymbolSize;
+      uint32_t NumberOfAuxBytes = NumberOfAuxRecords * SymbolSize;
+      uint32_t NumZeros = NumberOfAuxBytes - i->File.size();
+      OS.write(i->File.data(), i->File.size());
+      OS.write_zeros(NumZeros);
+    }
+    if (i->SectionDefinition) {
+      OS << binary_le(i->SectionDefinition->Length)
+         << binary_le(i->SectionDefinition->NumberOfRelocations)
+         << binary_le(i->SectionDefinition->NumberOfLinenumbers)
+         << binary_le(i->SectionDefinition->CheckSum)
+         << binary_le(static_cast<int16_t>(i->SectionDefinition->Number))
+         << binary_le(i->SectionDefinition->Selection)
+         << zeros(i->SectionDefinition->unused)
+         << binary_le(static_cast<int16_t>(i->SectionDefinition->Number >> 16));
+      OS.write_zeros(CP.getSymbolSize() - COFF::Symbol16Size);
+    }
+    if (i->CLRToken) {
+      OS << binary_le(i->CLRToken->AuxType) << zeros(i->CLRToken->unused1)
+         << binary_le(i->CLRToken->SymbolTableIndex)
+         << zeros(i->CLRToken->unused2);
+      OS.write_zeros(CP.getSymbolSize() - COFF::Symbol16Size);
+    }
+  }
+
+  // Output string table.
+  if (CP.Obj.Header.PointerToSymbolTable)
+    OS.write(&CP.StringTable[0], CP.StringTable.size());
+  return true;
+}
+
+namespace llvm {
+namespace yaml {
+
+int yaml2coff(llvm::COFFYAML::Object &Doc, raw_ostream &Out) {
+  COFFParser CP(Doc);
+  if (!CP.parse()) {
+    errs() << "yaml2obj: Failed to parse YAML file!\n";
+    return 1;
+  }
+
+  if (!layoutOptionalHeader(CP)) {
+    errs() << "yaml2obj: Failed to layout optional header for COFF file!\n";
+    return 1;
+  }
+
+  if (!layoutCOFF(CP)) {
+    errs() << "yaml2obj: Failed to layout COFF file!\n";
+    return 1;
+  }
+  if (!writeCOFF(CP, Out)) {
+    errs() << "yaml2obj: Failed to write COFF file!\n";
+    return 1;
+  }
+  return 0;
+}
+
+} // namespace yaml
+} // namespace llvm