Board Thread:Suggestions forum/@comment-43783253-20200115121717/@comment-27845944-20200216045304

73.5.90.101 wrote: Oh for crying out loud! Stone Giants are trolls! Just add in grey-skinned trolls that are twice to three times the size of Olog-hai! Problem solved! "In some of Tolkien's earliest writings giants were among the Úvanimor, or monster-folk, that were bred in the earth by Melkor (called Melko in the early tales) along with monsters, Nauglath (wicked dwarves), and ogres."

-Giants, LOTR Wiki

They were not trolls, they were probably either very large men or some other kind of beast. I would personally go with the movie version and have them be made of stone, and go with the concept of them just being cobblestone structures.