[llvm-cvtres] Reduce the set of dependencies of llvm-cvtres. NFC.

[mstorsjo]

Summary

Don't use createBinary() but call the WindowsResource class directly.
The createBinary() function references all supported object file
types and ends up pulling way more from all the underlying libraries
than what is necessary.

This shrinks llvm-cvtres from 4.6 MB to 463 KB.

[thakis]

Nice!

[amccarth]

Wow. Excellent. Thank you!

llvm/tools/llvm-cvtres/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
+  BinaryFormat
   Object
   Option
   Support
   )
 
 set(LLVM_TARGET_DEFINITIONS Opts.td)
 
 tablegen(LLVM Opts.inc -gen-opt-parser-defs)
 add_public_tablegen_target(CvtResTableGen)
 
 add_llvm_tool(llvm-cvtres
   llvm-cvtres.cpp
   )

llvm/tools/llvm-cvtres/llvm-cvtres.cpp

 //===- llvm-cvtres.cpp - Serialize .res files into .obj ---------*- C++ -*-===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 //
 // Serialize .res files into .obj files.  This is intended to be a
 // platform-independent port of Microsoft's cvtres.exe.
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/BinaryFormat/Magic.h"
 #include "llvm/Object/Binary.h"
 #include "llvm/Object/WindowsMachineFlag.h"
 #include "llvm/Object/WindowsResource.h"
 #include "llvm/Option/Arg.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Option/Option.h"
 #include "llvm/Support/BinaryStreamError.h"
 #include "llvm/Support/Error.h"
static LLVM_ATTRIBUTE_NORETURN void reportError(Twine Msg) {
   errs() << Msg;
   exit(1);
 }
 
 static void reportError(StringRef Input, std::error_code EC) {
   reportError(Twine(Input) + ": " + EC.message() + ".\n");
 }
 
+static void error(StringRef Input, Error EC) {
+  if (!EC)
+    return;
+  handleAllErrors(std::move(EC), [&](const ErrorInfoBase &EI) {
+    reportError(Twine(Input) + ": " + EI.message() + ".\n");
+  });
+}
+
 static void error(Error EC) {
   if (!EC)
     return;
   handleAllErrors(std::move(EC),
                   [&](const ErrorInfoBase &EI) { reportError(EI.message()); });
 }
 
 static uint32_t getTime() {
   std::time_t Now = time(nullptr);
   if (Now < 0 || !isUInt<32>(Now))
     return UINT32_MAX;
   return static_cast<uint32_t>(Now);
 }
 
 template <typename T> T error(Expected<T> EC) {
   if (!EC)
     error(EC.takeError());
   return std::move(EC.get());
 }
 
+template <typename T> T error(StringRef Input, Expected<T> EC) {
+  if (!EC)
+    error(Input, EC.takeError());
+  return std::move(EC.get());
+}
+
+template <typename T> T error(StringRef Input, ErrorOr<T> &&EC) {
+  return error(Input, errorOrToExpected(std::move(EC)));
+}
+
 int main(int Argc, const char **Argv) {
   InitLLVM X(Argc, Argv);
 
   CvtResOptTable T;
   unsigned MAI, MAC;
   ArrayRef<const char *> ArgsArr = makeArrayRef(Argv + 1, Argc - 1);
   opt::InputArgList InputArgs = T.ParseArgs(ArgsArr, MAI, MAC);
 
int main(int Argc, const char **Argv) {
   }
 
   if (Verbose)
     outs() << "Machine: " << machineToStr(MachineType) << '\n';
 
   WindowsResourceParser Parser;
 
   for (const auto &File : InputFiles) {
-    Expected<OwningBinary<Binary>> BinaryOrErr = createBinary(File);
-    if (!BinaryOrErr)
-      reportError(File, errorToErrorCode(BinaryOrErr.takeError()));
-
-    Binary &Binary = *BinaryOrErr.get().getBinary();
-
-    WindowsResource *RF = dyn_cast<WindowsResource>(&Binary);
-    if (!RF)
+    std::unique_ptr<MemoryBuffer> Buffer = error(
+        File, MemoryBuffer::getFileOrSTDIN(File, /*IsText=*/false,
+                                           /*RequiresNullTerminator=*/false));
+    file_magic Type = identify_magic(Buffer->getMemBufferRef().getBuffer());
+    if (Type != file_magic::windows_resource)
       reportError(File + ": unrecognized file format.\n");
+    std::unique_ptr<WindowsResource> Binary = error(
+        File,
+        WindowsResource::createWindowsResource(Buffer->getMemBufferRef()));
+
+    WindowsResource *RF = Binary.get();
 
     if (Verbose) {
       int EntryNumber = 0;
       ResourceEntryRef Entry = error(RF->getHeadEntry());
       bool End = false;
       while (!End) {
         error(Entry.moveNext(End));
         EntryNumber++;
int main(int Argc, const char **Argv) {
   if (!FileOrErr)
     reportError(OutputFile, errorToErrorCode(FileOrErr.takeError()));
   std::unique_ptr<FileOutputBuffer> FileBuffer = std::move(*FileOrErr);
   std::copy(OutputBuffer->getBufferStart(), OutputBuffer->getBufferEnd(),
             FileBuffer->getBufferStart());
   error(FileBuffer->commit());
 
   if (Verbose) {
-    Expected<OwningBinary<Binary>> BinaryOrErr = createBinary(OutputFile);
-    if (!BinaryOrErr)
-      reportError(OutputFile, errorToErrorCode(BinaryOrErr.takeError()));
-    Binary &Binary = *BinaryOrErr.get().getBinary();
+    std::unique_ptr<MemoryBuffer> Buffer =
+        error(OutputFile,
+              MemoryBuffer::getFileOrSTDIN(OutputFile, /*IsText=*/false,
+                                           /*RequiresNullTerminator=*/false));
+
     ScopedPrinter W(errs());
-    W.printBinaryBlock("Output File Raw Data", Binary.getData());
+    W.printBinaryBlock("Output File Raw Data",
+                       Buffer->getMemBufferRef().getBuffer());
   }
 
   return 0;
 }