Fission Decompiler Uses Two-Stage IR to Balance Machine Accuracy and Readability

Fission, a reverse-engineering and binary decompilation tool written in Rust, splits its internal pipeline into two distinct intermediate representations: NIR and HIR. NIR sits close to raw machine semantics, preserving details like register effects, operation widths, and side effects needed for reliable analysis. HIR operates at a higher level, focusing on recovering human-readable program structure such as loops, conditionals, and expressions. The separation addresses a core tension in decompilation — converting machine code to readable pseudocode too early risks discarding information that still matters downstream. Fission uses Sleigh for instruction decoding but owns all subsequent pipeline stages, including normalization, type recovery, control-flow analysis, and pseudocode rendering.