Put the drained olives, sun-dried tomatoes, and the roasted garlic into the food processor bowl. Pulse a few times until the olives and tomatoes are finely chopped.
If the mixture appears to be dry, add some of the reserved oil from the tomatoes one tablespoon at a time (no more than 3 or 4 tablespoons) until the mixture has a wet appearance.
Put the mixture into a small bowl and serve or refrigerate.