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

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 a stripped llvm-cvtres from 4.6 MB to 463 KB.

Differential Revision: https://reviews.llvm.org/D100833

Author: mstorsjo

llvm/tools/llvm-cvtres/CMakeLists.txt

@@ -1,4 +1,5 @@
 set(LLVM_LINK_COMPONENTS
+  BinaryFormat
   Object
   Option
   Support

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

@@ -11,6 +11,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/BinaryFormat/Magic.h"
 #include "llvm/Object/Binary.h"
 #include "llvm/Object/WindowsMachineFlag.h"
 #include "llvm/Object/WindowsResource.h"
@@ -75,6 +76,14 @@ 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;
@@ -95,6 +104,16 @@ template <typename T> T error(Expected<T> EC) {
   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);
 
@@ -155,15 +174,17 @@ int main(int Argc, const char **Argv) {
   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;
@@ -199,12 +220,14 @@ int main(int Argc, const char **Argv) {
   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;