Trim My View: An LLM-Based Code Query System for Module Retrieval in Robotic Firmware

The software compilation process has a tendency to obscure the original design of the system and makes it difficult both to identify individual components and discern their purpose simply by examining the resulting binary code. Although decompilation techniques attempt to recover higher-level source code from the machine code in question, they are not fully able to restore the semantics of the original functions. Furthermore, binaries are often stripped of metadata, and this makes it challenging to reverse engineer complex binary software. In this paper we show how a combination of binary decomposition techniques, decompilation passes, and LLM-powered function summarization can be used to build an economical engine to identify modules in stripped binaries and associate them with high-level natural language descriptions. We instantiated this technique with three underlying open-source LLMs -- CodeQwen, DeepSeek-Coder and CodeStral -- and measured its effectiveness in identifying modules in robotics firmware. This experimental evaluation involved 467 modules from four devices from the ArduPilot software suite, and showed that CodeStral, the best-performing backend LLM, achieves an average F1-score of 0.68 with an online running time of just a handful of seconds.