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Abstract This paper presents a new approach to improve static program analysis using Large Language Models (LLMs). The approachinterleavescalls to the static analyzer and queries to the LLM. The query to the LLM is constructed based on intermediate results from the static analysis, and subsequent static analysis uses the results from the LLM query. We apply our approach to the problem oferror-specification inference: given systems code written in C, infer the set of values that each function can return on error. Such error specifications aid in program understanding and can be used to find error-handling bugs. We implemented our approach by incorporating LLMs into EESI, the state-of-the-art static analysis for error-specification inference. Compared to EESI, our approach achieves higher recall (from an average of 52.55% to 77.83%) and higher F1-score (from an average of 0.612 to 0.804) while maintaining precision (from an average of 86.67% to 85.12%) on real-world benchmarks such as Apache HTTPD and MbedTLS. We also conducted experiments to understand the sources of imprecision in our LLM-assisted analysis as well as the impact of LLM nondeterminism on the analysis results. 

Abstract Source code is a form of human communication, albeit one where the information shared between the programmers reading and writing the code is constrained by the requirement that the code executes correctly. Programming languages are more syntactically constrained than natural languages, but they are also very expressive, allowing a great many different ways to express even very simple computations. Still, code written by developers is highly predictable, and many programming tools have taken advantage of this phenomenon, relying on language modelsurprisalas a guiding mechanism. While surprisal has been validated as a measure of cognitive load in natural language, its relation to human cognitive processes in code is still poorly understood. In this paper, we explore the relationship between surprisal and programmer preference at a small granularity—do programmers prefer more predictable expressions in code? Usingmeaning‐preserving transformations, we produce equivalent alternatives to developer‐written code expressions and run a corpus study on Java and Python projects. In general, language models rate the code expressions developerschooseto write as more predictable than these transformed alternatives. Then, we perform two human subject studies asking participants to choose between two equivalent snippets of Java code with different surprisal scores (one original and transformed). We find that programmersdoprefer more predictable variants, and that stronger language models like the transformer align more often and more consistently with these preferences.