Multiattack. The giant makes two longsword attacks.
Longsword. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit:18 (3d8 + 5) slashing damage, or 21 (3d10 + 5) slashing damage if used with both hands.
Rock. Ranged Weapon Attack: +8 to hit, range 60/240 ft., one target. Hit:21 (3d10 + 5) bludgeoning damage.