Passing commandline options and their help info

Beginners
,
1

I do have a problem/inconsistency with command-line options.
Assuming I have an option:

static cl::opt<bool> DarkArts("darkarts", cl::init(false), cl::desc("Enable dark arts."));

In LLVM 3.4.2 llc --help dumps the help message and uses a single dash:

  -darkarts           - Enable dark arts.

I got pretty used to the single dash approach, though I didn’t like it.

In LLVM 17.0.6 llc --help dumps the help message and uses a double dash:

  --darkarts          - Enable dark arts.

I can use Clang’s option -mllvm to pass option magic with a single dash or with a double dash (in both versions). That’s completely new to me.

Is one version (single dash or double dash) preferred? I would prefer the double dash.
So, there has been a change somewhere during development. Is this somewhere documented? I can’t find anything.

Boris

2

If both the old and new versions accept either single or double dash, then the only actual change has been to how the --help describes the option. I should think double dash would be preferred for long-name options, that has been the normal practice for a very long time.