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

This reverts commit d4c7e9fc63c10dbab0c30186ef8575474a704496.

This is done in order to address the failure of CrWinClangLLD etc. bots.
These throw an error of "side-by-side configuration is incorrect" during
compilation, which sounds suspiciously related to these manifest
changes.

Revert "Switch external cvtres.exe for llvm's own resource library."

This reverts commit 71fe8ef283a9dab9a3f21432c98466cbc23990d1.

llvm-svn: 306618
diff --git a/llvm/lib/BinaryFormat/Magic.cpp b/llvm/lib/BinaryFormat/Magic.cpp
index f24f22c..ca4d93f 100644
--- a/llvm/lib/BinaryFormat/Magic.cpp
+++ b/llvm/lib/BinaryFormat/Magic.cpp
@@ -51,8 +51,7 @@
       return file_magic::coff_import_library;
     }
     // Windows resource file
-    if (Magic.size() >= sizeof(COFF::WinResMagic) &&
-        memcmp(Magic.data(), COFF::WinResMagic, sizeof(COFF::WinResMagic)) == 0)
+    if (startswith(Magic, "\0\0\0\0\x20\0\0\0\xFF"))
       return file_magic::windows_resource;
     // 0x0000 = COFF unknown machine type
     if (Magic[1] == 0)
diff --git a/llvm/lib/Object/WindowsResource.cpp b/llvm/lib/Object/WindowsResource.cpp
index ff9b9ca..35d5dd4 100644
--- a/llvm/lib/Object/WindowsResource.cpp
+++ b/llvm/lib/Object/WindowsResource.cpp
@@ -36,19 +36,23 @@
 // 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 = WIN_RES_MAGIC_SIZE + WIN_RES_NULL_ENTRY_SIZE;
+  size_t LeadingSize = ResourceMagicSize + NullEntrySize;
   BBS = BinaryByteStream(Data.getBuffer().drop_front(LeadingSize),
                          support::little);
 }
 
 Expected<std::unique_ptr<WindowsResource>>
 WindowsResource::createWindowsResource(MemoryBufferRef Source) {
-  if (Source.getBufferSize() < WIN_RES_MAGIC_SIZE + WIN_RES_NULL_ENTRY_SIZE)
+  if (Source.getBufferSize() < ResourceMagicSize + NullEntrySize)
     return make_error<GenericBinaryError>(
         "File too small to be a resource file",
         object_error::invalid_file_type);
@@ -101,10 +105,12 @@
 }
 
 Error ResourceEntryRef::loadNext() {
-  const WinResHeaderPrefix *Prefix;
-  RETURN_IF_ERROR(Reader.readObject(Prefix));
+  uint32_t DataSize;
+  RETURN_IF_ERROR(Reader.readInteger(DataSize));
+  uint32_t HeaderSize;
+  RETURN_IF_ERROR(Reader.readInteger(HeaderSize));
 
-  if (Prefix->HeaderSize < MIN_HEADER_SIZE)
+  if (HeaderSize < MIN_HEADER_SIZE)
     return make_error<GenericBinaryError>("Header size is too small.",
                                           object_error::parse_failed);
 
@@ -112,13 +118,13 @@
 
   RETURN_IF_ERROR(readStringOrId(Reader, NameID, Name, IsStringName));
 
-  RETURN_IF_ERROR(Reader.padToAlignment(WIN_RES_HEADER_ALIGNMENT));
+  RETURN_IF_ERROR(Reader.padToAlignment(sizeof(uint32_t)));
 
   RETURN_IF_ERROR(Reader.readObject(Suffix));
 
-  RETURN_IF_ERROR(Reader.readArray(Data, Prefix->DataSize));
+  RETURN_IF_ERROR(Reader.readArray(Data, DataSize));
 
-  RETURN_IF_ERROR(Reader.padToAlignment(WIN_RES_DATA_ALIGNMENT));
+  RETURN_IF_ERROR(Reader.padToAlignment(sizeof(uint32_t)));
 
   return Error::success();
 }
@@ -319,6 +325,7 @@
   void writeDirectoryTree();
   void writeDirectoryStringTable();
   void writeFirstSectionRelocations();
+
   std::unique_ptr<MemoryBuffer> OutputBuffer;
   char *BufferStart;
   uint64_t CurrentOffset = 0;
@@ -462,6 +469,8 @@
   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;
 }