I'm surprised nobody has mentioned DIRE[0] yet. They did exactly this and got some very impressive results.
[0]: https://arxiv.org/abs/1909.09029 / J. Lacomis et al., "DIRE: A Neural Approach to Decompiled Identifier Naming," 2019 34th IEEE/ACM International Conference on Automated Software Engineering (ASE), 2019, pp. 628-639, doi: 10.1109/ASE.2019.00064.