As the size of publicly available codebases has grown dramatically in recent years, so has the interest in developing programming tools that solve software tasks by learning from these codebases. Yet, the problem of learning from programs has turned out to be harder than expected and thus, up to now, there has been little progress in terms of practical tools that benefit from the availability of these massive datasets.

This dissertation focuses on addressing this problem: we present new techniques that learn probabilistic models from large datasets of programs as well as new tools based on these probabilistic models which improve software development.

The thesis presents three new software systems (JSNice, Slang and DeepSyn) that learn from large datasets of programs and provide likely solutions to previously unsolved programming tasks including deobfuscation, static type prediction for dynamic languages, and code synthesis. All three of these systems were trained on thousands of open source projects and answer real-world queries in seconds and with high precision. One of these systems, JSNice, was publicly released and is already widely used in the JavaScript community.

An important ingredient of the thesis is leveraging static analysis techniques to extract semantic representations of programs and building powerful probabilistic models over these semantics (e.g., conditional random fields). Working at the semantic level also allows us to enforce important constraints on the predictions (e.g. typechecking). The net result is that our tools make predictions with better precision than approaches whose models are learned directly over program syntax.

Finally, the dissertation presents a new framework for addressing the problem of program synthesis with noise. Using this framework, we show how to construct programming-by-example (PBE) engines that handle incorrect examples, and introduce a new learning approach based on approximate empirical risk minimization. Based on the framework, we developed a new code synthesis system (DeepSyn) which generalizes prior work and provides state-of-the-art precision.

@phdthesis{raychev2016learning, title={Learning from large codebases}, author={Raychev, Veselin}, year={2016}, school={ETH Zurich}}