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(2n), PDCFA is in O(n6), and AAC is in O(n9logn).
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.Comment: in Proceedings of the 43rd Annual ACM SIGPLAN-SIGACT Symposium on
Principles of Programming Languages, 201