Interesting question. First, decide which platform you want to use, revolver vs semi auto, based on actually handling
a few guns. After that, I'd suggest one of the following:
Semi auto: #1, Glock in 10 mm Auto or #2, Glock in 357 Sig
Revolver: #1, 5-6 1/2# revolver 44 Mag or #2, 5-6 1/2" revolver in 357 Mag. I'd be more inclined to us a double action over a single action, but would consider both depending on availability and what you can best shoot.
W/ the 357 Mag and 44 Mag, you can use milder 38 Spec and 44 Spec loads for practice.
Hogs can be BIG and VERY thick animals. Although I like the 45 ACP as a self defense gun, I'm concerned it may not penetrate sufficiently on bigger hogs. This is one of the situations where, as long as you can handle the gun, too much gun would be better than too little gun....W/ a revolver, carry a full power load that uses a long, flat nose bullet (may also see it referred to as a wide meplat) that will penetrate deep while providing a good wound; FMJ and RN bullets will penetrate deep, but not cause as much damage. Here's a good example of an LFN load.LINK