Bootstrapping Library-Based Synthesis

• Published in: Static Analysis pp. 272 - 298
• Main Authors: Huang, Kangjing, Qiu, Xiaokang
• Format: Book Chapter
• Language: English
• Published: Cham Springer Nature Switzerland
• Series: Lecture Notes in Computer Science
• Subjects: Java; Libraries; Program sketching; Program synthesis
• ISBN: 9783031223075; 3031223071
• ISSN: 0302-9743; 1611-3349
• DOI: 10.1007/978-3-031-22308-2_13

Constraint-based program synthesis techniques have been widely used in numerous settings. However, synthesizing programs that use libraries remains a major challenge. To handle complex or black-box libraries, the state of the art is to provide carefully crafted mocks or models to the synthesizer, requiring extra manual work. We address this challenge by proposing Toshokan, a new synthesis framework as an alternative approach in which library-using programs can be generated without any user-provided artifacts at the cost of moderate performance overhead. The framework extends the classic counterexample-guided synthesis framework with a bootstrapping, log-based library model. The model collects input-output samples from running failed candidate programs on witness inputs. We prove that the framework is sound when a sound, bounded verifier is available, and also complete if the underlying synthesizer and verifier promise to produce minimal outputs. We implement and incorporate the framework to JSketch, a Java sketching tool. Experiments show that Toshokan can successfully synthesize programs that use a variety of libraries, ranging from mathematical functions to data structures. Comparing to state-of-the-art synthesis algorithms which use mocks or models, Toshokan reduces up to 159 lines of code of required manual inputs, at the cost of less than 40 s of performance overheads.