[Clang][Bundler] Fix for a potential memory leak [NFC]

[sdmitriev]

Summary

Bundler leaks memory if it is called with -type=o but given input isn't an object file (though it has to have a known binary type like IR, archive, etc...). Memory leak is happening when binary object returned the createBinary(...) call cannot be casted to an ObjectFile type. In this case returned BinaryOrErr object releases ownership of the binary, but no one is taking it (see line 626).

[Hahnfeld]

LG iff the following is correct: The leak is when dyn_cast can't cast and returns null, right? If so, please add into the summary (and do so for future revisions, it will speed up review).

[sdmitriev]

In D67416#1666208, @Hahnfeld wrote:

LG iff the following is correct: The leak is when dyn_cast can't cast and returns null, right? If so, please add into the summary (and do so for future revisions, it will speed up review).

Yes, exactly. Memory leak is happening when *BinaryOrErr cannot be casted to an ObjectFile. In this case BinaryOrErr releases ownership of the binary, but no one is taking it. I will add this to the summary.

cfe/trunk/tools/clang-offload-bundler/ClangOffloadBundler.cpp

 
 /// Return an appropriate object file handler. We use the specific object
 /// handler if we know how to deal with that format, otherwise we use a default
 /// binary file handler.
 static FileHandler *CreateObjectFileHandler(MemoryBuffer &FirstInput) {
   // Check if the input file format is one that we know how to deal with.
   Expected<std::unique_ptr<Binary>> BinaryOrErr = createBinary(FirstInput);
 
-  // Failed to open the input as a known binary. Use the default binary handler.
-  if (!BinaryOrErr) {
-    // We don't really care about the error (we just consume it), if we could
-    // not get a valid device binary object we use the default binary handler.
-    consumeError(BinaryOrErr.takeError());
-    return new BinaryFileHandler();
-  }
-
-  // We only support regular object files. If this is not an object file,
-  // default to the binary handler. The handler will be owned by the client of
-  // this function.
-  std::unique_ptr<ObjectFile> Obj(
-      dyn_cast<ObjectFile>(BinaryOrErr.get().release()));
-
-  if (!Obj)
+  // We only support regular object files. If failed to open the input as a
+  // known binary or this is not an object file use the default binary handler.
+  if (errorToBool(BinaryOrErr.takeError()) || !isa<ObjectFile>(*BinaryOrErr))
     return new BinaryFileHandler();
 
-  return new ObjectFileHandler(std::move(Obj));
+  // Otherwise create an object file handler. The handler will be owned by the
+  // client of this function.
+  return new ObjectFileHandler(
+      std::unique_ptr<ObjectFile>(cast<ObjectFile>(BinaryOrErr->release())));
 }
 
 /// Return an appropriate handler given the input files and options.
 static FileHandler *CreateFileHandler(MemoryBuffer &FirstInput) {
   if (FilesType == "i")
     return new TextFileHandler(/*Comment=*/"//");
   if (FilesType == "ii")
     return new TextFileHandler(/*Comment=*/"//");