Semantic Code Browsing

TL;DR

This paper introduces a semantic code browsing method that uses static analysis and an assertion-based query language to find code based on semantic properties, improving accuracy and flexibility over traditional syntactic search.

Contribution

It presents a fully automatic, semantics-based code search approach using static analysis and a novel query language, without relying on documentation or annotations.

Findings

Prototype implementation within the Ciao system demonstrates effectiveness.

Semantic search is more resilient to syntactic differences.

Approach surpasses signature matching in power and flexibility.

Abstract

Programmers currently enjoy access to a very high number of code repositories and libraries of ever increasing size. The ensuing potential for reuse is however hampered by the fact that searching within all this code becomes an increasingly difficult task. Most code search engines are based on syntactic techniques such as signature matching or keyword extraction. However, these techniques are inaccurate (because they basically rely on documentation) and at the same time do not offer very expressive code query languages. We propose a novel approach that focuses on querying for semantic characteristics of code obtained automatically from the code itself. Program units are pre-processed using static analysis techniques, based on abstract interpretation, obtaining safe semantic approximations. A novel, assertion-based code query language is used to express desired semantic characteristics of the code as partial specifications. Relevant code is found by comparing such partial specifications with the inferred semantics for program elements. Our approach is fully automatic and does not rely on user annotations or documentation. It is more powerful and flexible than signature matching because it is parametric on the abstract domain and properties, and does not require type definitions. Also, it reasons with relations between properties, such as implication and abstraction, rather than just equality. It is also more resilient to syntactic code differences. We describe the approach and report on a prototype implementation within the Ciao system. Under consideration for acceptance in TPLP.