SugarC: Scalable Desugaring of Real-World Preprocessor Usage into Pure C

Variability-aware analysis is critical for ensuring the quality of configurable C software. An important step toward the development of variability-aware analysis at scale is to transform real-world. software that uses both C and preprocessor into pure C code, by replacing the preprocessor's compile-time variability with C's runtime variability. In this work, we design and implement a desugaring tool, SugarC, that transforms away real-world preprocessor usage. SugarC augments C's formal grammar specification with translation rules, performs simultaneous type checking during desugaring, and introduces numerous optimizations to address challenges that appear in real world preprocessor usage. The experiments on DesugarBench, a benchmark consisting of 108 manually-created programs, show that SugarC supports many more language features than two existing desugaring tools. When applied on three real-world configurable C software, SugarC desugared 774 out of 813 files in the three programs, taking at most ten minutes in the worst case and less than two minutes for 95% of the C files.