Beyond Code Pairs: Dialogue-Based Data Generation for LLM Code Translation
Le Chen, Nuo Xu, Winson Chen, Bin Lei, Pei-Hung Lin, Dunzhi Zhou, Rajeev Thakur, Caiwen Ding, Ali Jannesari, Chunhua Liao
TL;DR
The paper tackles the difficulty of translating code in low-resource domains by introducing a dual-LLM dialogue-based data generation pipeline that integrates compiler and runtime feedback. By collecting multi-turn dialogues and intermediate reasoning (Questioner–Solver) along with verified translations, the authors fine-tune open-weight models to substantially improve compilation, execution, and unit-test success on Fortran→C++ and C++→CUDA. They demonstrate that dialogue-centered supervision outperforms traditional code-pair training, achieve strong results with midsize open models that rival proprietary systems, and release large-scale, diverse datasets with multiple supervision formats. This work proposes a general, scalable paradigm for domain-specific code translation that can accelerate HPC modernization and reduce reliance on large closed models.
Abstract
Large language models (LLMs) have shown remarkable capabilities in code translation, yet their performance deteriorates in low-resource programming domains such as Fortran and emerging frameworks like CUDA, where high-quality parallel data are scarce. We present an automated dataset generation pipeline featuring a dual-LLM Questioner-Solver design that incorporates external knowledge from compilers and runtime feedback. Beyond traditional source-target code pair datasets, our approach additionally generates (1) verified translations with unit tests for assessing functional consistency, and (2) multi-turn dialogues that capture the reasoning process behind translation refinement. Applied to Fortran -> C++ and C++ -> CUDA, the pipeline yields 3.64k and 3.93k dialogues, respectively. Fine-tuning on this data yields dramatic improvements in functional correctness, boosting unit test success rates by over 56% on the challenging C++-to-CUDA task. We show this data enables a 7B open-weight model to significantly outperform larger proprietary systems on key metrics like compilation success.
