Static analyses based on typestates are important in certifying correctness of code contracts. Such analyses rely on Deterministic Finite Automata (DFAs) to specify properties of an object. We target the analysis of contracts in low-latency environments, where many useful contracts are impractical to codify as DFAs and/or the size of their associated DFAs leads to sub-par performance. To address this bottleneck, we present a lightweight compositional typestate analyzer, based on an expressive specification language that can succinctly specify code contracts. By implementing it in the static analyzer Infer, we demonstrate considerable performance and usability benefits when compared to existing techniques. A central insight is to rely on a sub-class of DFAs whose analysis uses efficient bit-vector operations.

基于类型状态的静态分析对于证明代码契约的正确性很重要。此类分析依赖于确定性有限自动机 (DFA) 来指定对象的属性。我们的目标是分析低延迟环境中的合同，在这种情况下，许多有用的合同无法编码为 DFA 和/或其相关 DFA 的大小会导致低于标准的性能。为了解决这个瓶颈，我们提出了一个轻量级的组合类型状态分析器，它基于一种可以简洁地指定代码契约的表达规范语言。通过在静态分析器Infer中实现它，与现有技术相比，我们展示了相当大的性能和可用性优势。一个核心观点是依赖于 DFA 的一个子类，其分析使用有效的位向量操作。