Revert "Revert "Replace trivial use of external rc.exe by writing our own .res file.""

[ecbeckmann]

Summary

This reverts commit 51931072a7c9a52540baf76fc30ef391d2529a2f.

This revert was originally done because the integrations of the new
WindowsResource library into LLD was causing error in chromium, due to
bugs in how resource sections were handled. These bugs were fixed,
meaning that the features may be reintegrated.

lld/trunk/COFF/DriverUtils.cpp

 
 #include "Config.h"
 #include "Driver.h"
 #include "Error.h"
 #include "Memory.h"
 #include "Symbols.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/StringSwitch.h"
+#include "llvm/BinaryFormat/COFF.h"
 #include "llvm/Object/COFF.h"
+#include "llvm/Object/WindowsResource.h"
 #include "llvm/Option/Arg.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Option/Option.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/FileUtilities.h"
+#include "llvm/Support/MathExtras.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/Program.h"
 #include "llvm/Support/raw_ostream.h"
 #include <memory>
 
 using namespace llvm::COFF;
 using namespace llvm;
 using llvm::cl::ExpandResponseFiles;
 using llvm::cl::TokenizeWindowsCommandLine;
 using llvm::sys::Process;
 
 namespace lld {
 namespace coff {
 namespace {
 
+const uint16_t SUBLANG_ENGLISH_US = 0x0409;
+const uint16_t RT_MANIFEST = 24;
+
 class Executor {
 public:
   explicit Executor(StringRef S) : Prog(Saver.save(S)) {}
   void add(StringRef S) { Args.push_back(Saver.save(S)); }
   void add(std::string &S) { Args.push_back(Saver.save(S)); }
   void add(Twine S) { Args.push_back(Saver.save(S)); }
   void add(const char *S) { Args.push_back(Saver.save(S)); }
 
if (Arg.startswith_lower("uiaccess=")) {
       Arg = Arg.substr(strlen("uiaccess="));
       std::tie(Config->ManifestUIAccess, Arg) = Arg.split(" ");
       continue;
     }
     fatal("invalid option " + Arg);
   }
 }
 
-// Quote each line with "". Existing double-quote is converted
-// to two double-quotes.
-static void quoteAndPrint(raw_ostream &Out, StringRef S) {
-  while (!S.empty()) {
-    StringRef Line;
-    std::tie(Line, S) = S.split("\n");
-    if (Line.empty())
-      continue;
-    Out << '\"';
-    for (int I = 0, E = Line.size(); I != E; ++I) {
-      if (Line[I] == '\"') {
-        Out << "\"\"";
-      } else {
-        Out << Line[I];
-      }
-    }
-    Out << "\"\n";
-  }
-}
-
 // An RAII temporary file class that automatically removes a temporary file.
 namespace {
 class TemporaryFile {
 public:
   TemporaryFile(StringRef Prefix, StringRef Extn, StringRef Contents = "") {
     SmallString<128> S;
     if (auto EC = sys::fs::createTemporaryFile("lld-" + Prefix, Extn, S))
       fatal(EC, "cannot create a temporary file");
for (StringRef Filename : Config->ManifestInput) {
     E.add(Filename);
   }
   E.add("/nologo");
   E.add("/out:" + StringRef(File2.Path));
   E.run();
   return readFile(File2.Path);
 }
 
+static std::unique_ptr<MemoryBuffer>
+createMemoryBufferForManifestRes(size_t ManifestSize) {
+  size_t ResSize = alignTo(object::WIN_RES_MAGIC_SIZE +
+                           object::WIN_RES_NULL_ENTRY_SIZE +
+                           sizeof(object::WinResHeaderPrefix) +
+                           sizeof(object::WinResIDs) +
+                           sizeof(object::WinResHeaderSuffix) +
+                           ManifestSize,
+                           object::WIN_RES_DATA_ALIGNMENT);
+  return MemoryBuffer::getNewMemBuffer(ResSize);
+}
+
+static void writeResFileHeader(char *&Buf) {
+  memcpy(Buf, COFF::WinResMagic, sizeof(COFF::WinResMagic));
+  Buf += sizeof(COFF::WinResMagic);
+  memset(Buf, 0, object::WIN_RES_NULL_ENTRY_SIZE);
+  Buf += object::WIN_RES_NULL_ENTRY_SIZE;
+}
+
+static void writeResEntryHeader(char *&Buf, size_t ManifestSize) {
+  // Write the prefix.
+  auto *Prefix = reinterpret_cast<object::WinResHeaderPrefix *>(Buf);
+  Prefix->DataSize = ManifestSize;
+  Prefix->HeaderSize = sizeof(object::WinResHeaderPrefix) +
+                       sizeof(object::WinResIDs) +
+                       sizeof(object::WinResHeaderSuffix);
+  Buf += sizeof(object::WinResHeaderPrefix);
+
+  // Write the Type/Name IDs.
+  auto *IDs = reinterpret_cast<object::WinResIDs *>(Buf);
+  IDs->setType(RT_MANIFEST);
+  IDs->setName(Config->ManifestID);
+  Buf += sizeof(object::WinResIDs);
+
+  // Write the suffix.
+  auto *Suffix = reinterpret_cast<object::WinResHeaderSuffix *>(Buf);
+  Suffix->DataVersion = 0;
+  Suffix->MemoryFlags = object::WIN_RES_PURE_MOVEABLE;
+  Suffix->Language = SUBLANG_ENGLISH_US;
+  Suffix->Version = 0;
+  Suffix->Characteristics = 0;
+  Buf += sizeof(object::WinResHeaderSuffix);
+}
+
 // Create a resource file containing a manifest XML.
 std::unique_ptr<MemoryBuffer> createManifestRes() {
-  // Create a temporary file for the resource script file.
-  TemporaryFile RCFile("manifest", "rc");
+  std::string Manifest = createManifestXml();
 
-  // Open the temporary file for writing.
-  std::error_code EC;
-  raw_fd_ostream Out(RCFile.Path, EC, sys::fs::F_Text);
-  if (EC)
-    fatal(EC, "failed to open " + RCFile.Path);
+  std::unique_ptr<MemoryBuffer> Res =
+      createMemoryBufferForManifestRes(Manifest.size());
 
-  // Write resource script to the RC file.
-  Out << "#define LANG_ENGLISH 9\n"
-      << "#define SUBLANG_DEFAULT 1\n"
-      << "#define APP_MANIFEST " << Config->ManifestID << "\n"
-      << "#define RT_MANIFEST 24\n"
-      << "LANGUAGE LANG_ENGLISH, SUBLANG_DEFAULT\n"
-      << "APP_MANIFEST RT_MANIFEST {\n";
-  quoteAndPrint(Out, createManifestXml());
-  Out << "}\n";
-  Out.close();
-
-  // Create output resource file.
-  TemporaryFile ResFile("output-resource", "res");
-
-  Executor E("rc.exe");
-  E.add("/fo");
-  E.add(ResFile.Path);
-  E.add("/nologo");
-  E.add(RCFile.Path);
-  E.run();
-  return ResFile.getMemoryBuffer();
+  char *Buf = const_cast<char *>(Res->getBufferStart());
+  writeResFileHeader(Buf);
+  writeResEntryHeader(Buf, Manifest.size());
+
+  // Copy the manifest data into the .res file.
+  std::copy(Manifest.begin(), Manifest.end(), Buf);
+  return Res;
 }
 
 void createSideBySideManifest() {
   std::string Path = Config->ManifestFile;
   if (Path == "")
     Path = Config->OutputFile + ".manifest";
   std::error_code EC;
   raw_fd_ostream Out(Path, EC, sys::fs::F_Text);
fatal("/failifmismatch: mismatch detected: " + Existing + " and " + V +
           " for key " + K);
   Config->MustMatch[K] = V;
 }
 
 // Convert Windows resource files (.res files) to a .obj file
 // using cvtres.exe.
 std::unique_ptr<MemoryBuffer>
 convertResToCOFF(const std::vector<MemoryBufferRef> &MBs) {
-  // Create an output file path.
-  TemporaryFile File("resource-file", "obj");
-
-  // Execute cvtres.exe.
-  Executor E("cvtres.exe");
-  E.add("/machine:" + machineToStr(Config->Machine));
-  E.add("/readonly");
-  E.add("/nologo");
-  E.add("/out:" + Twine(File.Path));
+  object::WindowsResourceParser Parser;
 
-  // We must create new files because the memory buffers we have may have no
-  // underlying file still existing on the disk.
-  // It happens if it was created from a TemporaryFile, which usually delete
-  // the file just after creating the MemoryBuffer.
-  std::vector<TemporaryFile> ResFiles;
-  ResFiles.reserve(MBs.size());
   for (MemoryBufferRef MB : MBs) {
-    // We store the temporary file in a vector to avoid deletion
-    // before running cvtres
-    ResFiles.emplace_back("resource-file", "res");
-    TemporaryFile& ResFile = ResFiles.back();
-    // Write the content of the resource in a temporary file
-    std::error_code EC;
-    raw_fd_ostream OS(ResFile.Path, EC, sys::fs::F_None);
-    if (EC)
-      fatal(EC, "failed to open " + ResFile.Path);
-    OS << MB.getBuffer();
-    OS.close();
-
-    E.add(ResFile.Path);
+    std::unique_ptr<object::Binary> Bin = check(object::createBinary(MB));
+    object::WindowsResource *RF = dyn_cast<object::WindowsResource>(Bin.get());
+    if (!RF)
+      fatal("cannot compile non-resource file as resource");
+    if (auto EC = Parser.parse(RF))
+      fatal(EC, "failed to parse .res file");
   }
 
-  E.run();
-  return File.getMemoryBuffer();
+  Expected<std::unique_ptr<MemoryBuffer>> E =
+      llvm::object::writeWindowsResourceCOFF(Config->Machine, Parser);
+  if (!E)
+    fatal(errorToErrorCode(E.takeError()), "failed to write .res to COFF");
+  return std::move(E.get());
 }
 
 // Run MSVC link.exe for given in-memory object files.
 // Command line options are copied from those given to LLD.
 // This is for the /msvclto option.
 void runMSVCLinker(std::string Rsp, ArrayRef<StringRef> Objects) {
   // Write the in-memory object files to disk.
   std::vector<TemporaryFile> Temps;

lld/trunk/test/COFF/combined-resources.test

 // Check that lld properly handles merging multiple .res files.
 // The inputs were generated with the following commands, using the original
 // Windows rc.exe
 // > rc /fo combined-resources.res /nologo combined-resources.rc
 // > rc /fo combined-resources-2.res /nologo combined-resources-2.rc
 
-# REQUIRES: winres
-
 # RUN: yaml2obj < %p/Inputs/ret42.yaml > %t.obj
 # RUN: lld-link /out:%t.exe /entry:main %t.obj %p/Inputs/resource.res \
 # RUN:   %p/Inputs/combined-resources.res %p/Inputs/combined-resources-2.res
 
 # RUN: llvm-readobj -coff-resources -file-headers %t.exe | FileCheck %s
 
 
 CHECK:      ResourceTableRVA: 0x1000
 CHECK-NEXT: ResourceTableSize: 0xC1C
 CHECK-DAG:  Resources [
 CHECK-NEXT:   Total Number of Resources: 13

lld/trunk/test/COFF/def-name.test

-# REQUIRES: winres
-
 # RUN: rm -rf %t
 # RUN: mkdir -p %t
 # RUN: cd %t
 # RUN: yaml2obj < %p/Inputs/ret42.yaml > in.obj
 
 # RUN: lld-link /entry:main in.obj
 # RUN: lld-link /entry:main /dll in.obj
 

lld/trunk/test/COFF/dll.test

-# REQUIRES: winres
-
 # RUN: yaml2obj < %p/Inputs/export.yaml > %t.obj
 # RUN: lld-link /out:%t.dll /dll %t.obj /export:exportfn1 /export:exportfn2 \
 # RUN:   /export:mangled
 # RUN: llvm-objdump -p %t.dll | FileCheck -check-prefix=EXPORT %s
 
 EXPORT:      Export Table:
 EXPORT:      DLL name: dll.test.tmp.dll
 EXPORT:      Ordinal      RVA  Name

lld/trunk/test/COFF/dllimport-gc.test

-# REQUIRES: winres
-
 # RUN: yaml2obj < %p/Inputs/export.yaml > %t-lib.obj
 # RUN: lld-link /out:%t.dll /dll %t-lib.obj /implib:%t.lib /export:exportfn1
 
 # RUN: yaml2obj < %p/Inputs/oldname.yaml > %t-oldname.obj
 
 # RUN: yaml2obj < %s > %t.obj
 
 # RUN: lld-link /out:%t1.exe /entry:main %t.obj %t-oldname.obj %t.lib

lld/trunk/test/COFF/manifestinput.test

-# REQUIRES: winres
+# REQUIRES: win_mt
 
 # RUN: yaml2obj %p/Inputs/ret42.yaml > %t.obj
 # RUN: lld-link /out:%t.exe /entry:main \
 # RUN:   /manifestuac:"level='requireAdministrator'" \
 # RUN:   /manifestinput:%p/Inputs/manifestinput.test %t.obj
 # RUN: FileCheck %s < %t.exe.manifest
 
 CHECK: <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
 CHECK: <assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0"><dependency><dependentAssembly><assemblyIdentity type="win32" name="Microsoft.Windows.Common-Controls" version="6.0.0.0" processorArchitecture="*" publicKeyToken="6595b64144ccf1df" language="*"></assemblyIdentity></dependentAssembly></dependency><trustInfo><security><requestedPrivileges><requestedExecutionLevel level="requireAdministrator" uiAccess="false"></requestedExecutionLevel></requestedPrivileges></security></trustInfo></assembly>
+
+# RUN: yaml2obj %p/Inputs/ret42.yaml > %t.obj
+# RUN: lld-link /out:%t.exe /entry:main \
+# RUN:   /manifest:embed \
+# RUN:   /manifestuac:"level='requireAdministrator'" \
+# RUN:   /manifestinput:%p/Inputs/manifestinput.test %t.obj
+# RUN: llvm-readobj -coff-resources -file-headers %t.exe | FileCheck %s \
+# RUN:   -check-prefix TEST_EMBED
+
+TEST_EMBED:          ResourceTableRVA: 0x1000
+TEST_EMBED-NEXT:     ResourceTableSize: 0x298
+TEST_EMBED-DAG:      Resources [
+TEST_EMBED-NEXT:       Total Number of Resources: 1 
+TEST_EMBED-DAG:        Number of String Entries: 0
+TEST_EMBED-NEXT:       Number of ID Entries: 1
+TEST_EMBED-NEXT:       Type: kRT_MANIFEST (ID 24) [
+TEST_EMBED-NEXT:         Table Offset: 0x18
+TEST_EMBED-NEXT:         Number of String Entries: 0
+TEST_EMBED-NEXT:         Number of ID Entries: 1
+TEST_EMBED-NEXT:         Name: (ID 1) [
+TEST_EMBED-NEXT:           Table Offset: 0x30
+TEST_EMBED-NEXT:           Number of String Entries: 0
+TEST_EMBED-NEXT:           Number of ID Entries: 1
+TEST_EMBED-NEXT:           Language: (ID 1033) [
+TEST_EMBED-NEXT:             Entry Offset: 0x48

lld/trunk/test/COFF/noentry.test

-# REQUIRES: winres
-
 # RUN: yaml2obj < %p/Inputs/export.yaml > %t.obj
 # RUN: lld-link /out:%t.dll /dll %t.obj
 # RUN: llvm-readobj -file-headers %t.dll | FileCheck -check-prefix=ENTRY %s
 # RUN: lld-link /out:%t.dll /dll /noentry %t.obj
 # RUN: llvm-readobj -file-headers %t.dll | FileCheck -check-prefix=NOENTRY %s
 
 ENTRY:   AddressOfEntryPoint: 0x1000
 NOENTRY: AddressOfEntryPoint: 0x0

lld/trunk/test/COFF/out.test

-# REQUIRES: winres
 # RUN: yaml2obj < %p/Inputs/ret42.yaml > %t.obj
 
 # RUN: mkdir -p %T/out/tmp
 # RUN: cp %t.obj %T/out/out1.obj
 # RUN: cp %t.obj %T/out/tmp/out2
 # RUN: cp %t.obj %T/out/tmp/out3.xyz
 
 # RUN: rm -f out1.exe out2.exe out3.exe out3.dll

lld/trunk/test/COFF/resource.test

-# REQUIRES: winres
-
 # RUN: yaml2obj < %p/Inputs/ret42.yaml > %t.obj
 # RUN: lld-link /out:%t.exe /entry:main %t.obj %p/Inputs/resource.res
 
 # Check if the binary contains UTF-16LE string "Hello" copied from resource.res.
 # RUN: FileCheck --check-prefix=EXE %s < %t.exe
 
 EXE: {{H.e.l.l.o}}
 

lld/trunk/test/lit.cfg

if re.search(r'Sparc', archs):
     config.available_features.add('sparc')
 if re.search(r'X86', archs):
     config.available_features.add('x86')
 llvm_config_cmd.wait()
 
 # Set a fake constant version so that we get consitent output.
 config.environment['LLD_VERSION'] = 'LLD 1.0'
 
-# Check if Windows resource file compiler exists.
-cvtres = lit.util.which('cvtres', config.environment['PATH'])
-rc = lit.util.which('rc', config.environment['PATH'])
-if cvtres and rc:
-    config.available_features.add('winres')
+# Indirectly check if the mt.exe Microsoft utility exists by searching for
+# cvtres, which always accompanies it.
+if lit.util.which('cvtres', config.environment['PATH']):
+    config.available_features.add('win_mt')

llvm/trunk/include/llvm/BinaryFormat/COFF.h

static const char BigObjMagic[] = {
     '\xaf', '\x20', '\xfa', '\xf6', '\x6a', '\xa4', '\xdc', '\xb8',
 };
 
 static const char ClGlObjMagic[] = {
     '\x38', '\xfe', '\xb3', '\x0c', '\xa5', '\xd9', '\xab', '\x4d',
     '\xac', '\x9b', '\xd6', '\xb6', '\x22', '\x26', '\x53', '\xc2',
 };
 
+// The signature bytes that start a .res file.
+static const char WinResMagic[] = {
+    '\x00', '\x00', '\x00', '\x00', '\x20', '\x00', '\x00', '\x00',
+    '\xff', '\xff', '\x00', '\x00', '\xff', '\xff', '\x00', '\x00',
+};
+
 // Sizes in bytes of various things in the COFF format.
 enum {
   Header16Size = 20,
   Header32Size = 56,
   NameSize = 8,
   Symbol16Size = 18,
   Symbol32Size = 20,
   SectionSize = 40,

llvm/trunk/include/llvm/Object/WindowsResource.h

 #include "llvm/Support/ConvertUTF.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ScopedPrinter.h"
 
 #include <map>
 
 namespace llvm {
-
 namespace object {
 
 class WindowsResource;
 
-enum class Machine { UNKNOWN, ARM, X64, X86 };
+const size_t WIN_RES_MAGIC_SIZE = 16;
+const size_t WIN_RES_NULL_ENTRY_SIZE = 16;
+const uint32_t WIN_RES_HEADER_ALIGNMENT = 4;
+const uint32_t WIN_RES_DATA_ALIGNMENT = 4;
+const uint16_t WIN_RES_PURE_MOVEABLE = 0x0030;
+
+struct WinResHeaderPrefix {
+  support::ulittle32_t DataSize;
+  support::ulittle32_t HeaderSize;
+};
+
+// Type and Name may each either be an integer ID or a string.  This struct is
+// only used in the case where they are both IDs.
+struct WinResIDs {
+  uint16_t TypeFlag;
+  support::ulittle16_t TypeID;
+  uint16_t NameFlag;
+  support::ulittle16_t NameID;
+
+  void setType(uint16_t ID) {
+    TypeFlag = 0xffff;
+    TypeID = ID;
+  }
+
+  void setName(uint16_t ID) {
+    NameFlag = 0xffff;
+    NameID = ID;
+  }
+};
+
+struct WinResHeaderSuffix {
+  support::ulittle32_t DataVersion;
+  support::ulittle16_t MemoryFlags;
+  support::ulittle16_t Language;
+  support::ulittle32_t Version;
+  support::ulittle32_t Characteristics;
+};
 
 class ResourceEntryRef {
 public:
   Error moveNext(bool &End);
   bool checkTypeString() const { return IsStringType; }
   ArrayRef<UTF16> getTypeString() const { return Type; }
   uint16_t getTypeID() const { return TypeID; }
   bool checkNameString() const { return IsStringName; }
   ArrayRef<UTF16> getNameString() const { return Name; }
   uint16_t getNameID() const { return NameID; }
   uint16_t getLanguage() const { return Suffix->Language; }
   uint16_t getMajorVersion() const { return Suffix->Version >> 16; }
   uint16_t getMinorVersion() const { return Suffix->Version; }
   uint32_t getCharacteristics() const { return Suffix->Characteristics; }
   ArrayRef<uint8_t> getData() const { return Data; }
 
 private:
   friend class WindowsResource;
 
   ResourceEntryRef(BinaryStreamRef Ref, const WindowsResource *Owner,
                    Error &Err);
 
   Error loadNext();
 
-  struct HeaderSuffix {
-    support::ulittle32_t DataVersion;
-    support::ulittle16_t MemoryFlags;
-    support::ulittle16_t Language;
-    support::ulittle32_t Version;
-    support::ulittle32_t Characteristics;
-  };
-
   BinaryStreamReader Reader;
   bool IsStringType;
   ArrayRef<UTF16> Type;
   uint16_t TypeID;
   bool IsStringName;
   ArrayRef<UTF16> Name;
   uint16_t NameID;
-  const HeaderSuffix *Suffix = nullptr;
+  const WinResHeaderSuffix *Suffix = nullptr;
   ArrayRef<uint8_t> Data;
   const WindowsResource *OwningRes = nullptr;
 };
 
 class WindowsResource : public Binary {
 public:
   Expected<ResourceEntryRef> getHeadEntry();
 

llvm/trunk/lib/BinaryFormat/Magic.cpp

if (startswith(Magic, "\0\0\xFF\xFF")) {
       const char *Start = Magic.data() + offsetof(COFF::BigObjHeader, UUID);
       if (memcmp(Start, COFF::BigObjMagic, sizeof(COFF::BigObjMagic)) == 0)
         return file_magic::coff_object;
       if (memcmp(Start, COFF::ClGlObjMagic, sizeof(COFF::BigObjMagic)) == 0)
         return file_magic::coff_cl_gl_object;
       return file_magic::coff_import_library;
     }
     // Windows resource file
-    if (startswith(Magic, "\0\0\0\0\x20\0\0\0\xFF"))
+    if (Magic.size() >= sizeof(COFF::WinResMagic) &&
+        memcmp(Magic.data(), COFF::WinResMagic, sizeof(COFF::WinResMagic)) == 0)
       return file_magic::windows_resource;
     // 0x0000 = COFF unknown machine type
     if (Magic[1] == 0)
       return file_magic::coff_object;
     if (startswith(Magic, "\0asm"))
       return file_magic::wasm_object;
     break;
   }

llvm/trunk/lib/Object/WindowsResource.cpp

if (auto EC = X)                                                             \
     return EC;
 
 const uint32_t MIN_HEADER_SIZE = 7 * sizeof(uint32_t) + 2 * sizeof(uint16_t);
 
 // COFF files seem to be inconsistent with alignment between sections, just use
 // 8-byte because it makes everyone happy.
 const uint32_t SECTION_ALIGNMENT = sizeof(uint64_t);
 
-static const size_t ResourceMagicSize = 16;
-
-static const size_t NullEntrySize = 16;
-
 uint32_t WindowsResourceParser::TreeNode::StringCount = 0;
 uint32_t WindowsResourceParser::TreeNode::DataCount = 0;
 
 WindowsResource::WindowsResource(MemoryBufferRef Source)
     : Binary(Binary::ID_WinRes, Source) {
-  size_t LeadingSize = ResourceMagicSize + NullEntrySize;
+  size_t LeadingSize = WIN_RES_MAGIC_SIZE + WIN_RES_NULL_ENTRY_SIZE;
   BBS = BinaryByteStream(Data.getBuffer().drop_front(LeadingSize),
                          support::little);
 }
 
 Expected<std::unique_ptr<WindowsResource>>
 WindowsResource::createWindowsResource(MemoryBufferRef Source) {
-  if (Source.getBufferSize() < ResourceMagicSize + NullEntrySize)
+  if (Source.getBufferSize() < WIN_RES_MAGIC_SIZE + WIN_RES_NULL_ENTRY_SIZE)
     return make_error<GenericBinaryError>(
         "File too small to be a resource file",
         object_error::invalid_file_type);
   std::unique_ptr<WindowsResource> Ret(new WindowsResource(Source));
   return std::move(Ret);
 }
 
 Expected<ResourceEntryRef> WindowsResource::getHeadEntry() {
if (IsString) {
     RETURN_IF_ERROR(Reader.readWideString(Str));
   } else
     RETURN_IF_ERROR(Reader.readInteger(ID));
 
   return Error::success();
 }
 
 Error ResourceEntryRef::loadNext() {
-  uint32_t DataSize;
-  RETURN_IF_ERROR(Reader.readInteger(DataSize));
-  uint32_t HeaderSize;
-  RETURN_IF_ERROR(Reader.readInteger(HeaderSize));
+  const WinResHeaderPrefix *Prefix;
+  RETURN_IF_ERROR(Reader.readObject(Prefix));
 
-  if (HeaderSize < MIN_HEADER_SIZE)
+  if (Prefix->HeaderSize < MIN_HEADER_SIZE)
     return make_error<GenericBinaryError>("Header size is too small.",
                                           object_error::parse_failed);
 
   RETURN_IF_ERROR(readStringOrId(Reader, TypeID, Type, IsStringType));
 
   RETURN_IF_ERROR(readStringOrId(Reader, NameID, Name, IsStringName));
 
-  RETURN_IF_ERROR(Reader.padToAlignment(sizeof(uint32_t)));
+  RETURN_IF_ERROR(Reader.padToAlignment(WIN_RES_HEADER_ALIGNMENT));
 
   RETURN_IF_ERROR(Reader.readObject(Suffix));
 
-  RETURN_IF_ERROR(Reader.readArray(Data, DataSize));
+  RETURN_IF_ERROR(Reader.readArray(Data, Prefix->DataSize));
 
-  RETURN_IF_ERROR(Reader.padToAlignment(sizeof(uint32_t)));
+  RETURN_IF_ERROR(Reader.padToAlignment(WIN_RES_DATA_ALIGNMENT));
 
   return Error::success();
 }
 
 WindowsResourceParser::WindowsResourceParser() : Root(false) {}
 
 Error WindowsResourceParser::parse(WindowsResource *WR) {
   auto EntryOrErr = WR->getHeadEntry();
private:
   void writeSecondSectionHeader();
   void writeFirstSection();
   void writeSecondSection();
   void writeSymbolTable();
   void writeStringTable();
   void writeDirectoryTree();
   void writeDirectoryStringTable();
   void writeFirstSectionRelocations();
-
   std::unique_ptr<MemoryBuffer> OutputBuffer;
   char *BufferStart;
   uint64_t CurrentOffset = 0;
   COFF::MachineTypes MachineType;
   const WindowsResourceParser::TreeNode &Resources;
   const ArrayRef<std::vector<uint8_t>> Data;
   uint64_t FileSize;
   uint32_t SymbolTableOffset;
void WindowsResourceCOFFWriter::writeFirstSectionHeader() {
   SectionOneHeader->VirtualSize = 0;
   SectionOneHeader->VirtualAddress = 0;
   SectionOneHeader->SizeOfRawData = SectionOneSize;
   SectionOneHeader->PointerToRawData = SectionOneOffset;
   SectionOneHeader->PointerToRelocations = SectionOneRelocations;
   SectionOneHeader->PointerToLinenumbers = 0;
   SectionOneHeader->NumberOfRelocations = Data.size();
   SectionOneHeader->NumberOfLinenumbers = 0;
-  SectionOneHeader->Characteristics = COFF::IMAGE_SCN_ALIGN_1BYTES;
-  SectionOneHeader->Characteristics += COFF::IMAGE_SCN_CNT_INITIALIZED_DATA;
   SectionOneHeader->Characteristics += COFF::IMAGE_SCN_CNT_INITIALIZED_DATA;
   SectionOneHeader->Characteristics += COFF::IMAGE_SCN_MEM_READ;
 }
 
 void WindowsResourceCOFFWriter::writeSecondSectionHeader() {
   // Write the second section header.
   CurrentOffset += sizeof(coff_section);
   auto *SectionTwoHeader =

llvm/trunk/unittests/BinaryFormat/TestFileMagic.cpp

 const char macho_dynamic_linker[] =
     "\xfe\xed\xfa\xce........\x00\x00\x00\x07............";
 const char macho_bundle[] =
     "\xfe\xed\xfa\xce........\x00\x00\x00\x08............";
 const char macho_dsym_companion[] =
     "\xfe\xed\xfa\xce........\x00\x00\x00\x0a............";
 const char macho_kext_bundle[] =
     "\xfe\xed\xfa\xce........\x00\x00\x00\x0b............";
-const char windows_resource[] = "\x00\x00\x00\x00\x020\x00\x00\x00\xff";
+const char windows_resource[] =
+    "\x00\x00\x00\x00\x020\x00\x00\x00\xff\xff\x00\x00\xff\xff\x00\x00";
 const char macho_dynamically_linked_shared_lib_stub[] =
     "\xfe\xed\xfa\xce........\x00\x00\x00\x09............";
 
 TEST_F(MagicTest, Magic) {
   struct type {
     const char *filename;
     const char *magic_str;
     size_t magic_str_len;