Pushdown Control-Flow Analysis for Free
Abstract
Traditional control-flow analysis (CFA) for higher-order languages, whether implemented by constraint-solving or abstract interpretation, introduces spurious connections between callers and callees. Two distinct invocations of a function will necessarily pollute one another's return-flow. Recently, three distinct approaches have been published which provide perfect call-stack precision in a computable manner: CFA2, PDCFA, and AAC. Unfortunately, CFA2 and PDCFA are difficult to implement and require significant engineering effort. Furthermore, all three are computationally expensive; for a monovariant analysis, CFA2 is in $O(2^n)$, PDCFA is in $O(n^6)$, and AAC is in $O(n^9 log n)$. In this paper, we describe a new technique that builds on these but is both straightforward to implement and computationally inexpensive. The crucial insight is an unusual state-dependent allocation strategy for the addresses of continuation. Our technique imposes only a constant-factor overhead on the underlying analysis and, with monovariance, costs only O(n3) in the worst case. This paper presents the intuitions behind this development, a proof of the precision of this analysis, and benchmarks demonstrating its efficacy.
- Publication:
-
arXiv e-prints
- Pub Date:
- July 2015
- DOI:
- 10.48550/arXiv.1507.03137
- arXiv:
- arXiv:1507.03137
- Bibcode:
- 2015arXiv150703137G
- Keywords:
-
- Computer Science - Programming Languages;
- D.3.4
- E-Print:
- in Proceedings of the 43rd Annual ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages, 2016