Context-sensitive global analysis of large code bases can be expensive, which can be specially problematic in interactive uses of analyzers. However, in practice each development iteration implies small modifications which are often isolated within a few modules, and analysis cost can be reduced by reusing the results of previous analyses.

This has been achieved to date on one hand through modular analysis, which can reduce the memory consumption and often localize the computation during reanalysis mainly to the modules affected by changes. In parallel, context-sensitive incremental fixpoints have been proposed that achieve cost reductions at finer levels of granularity, such as changes in program lines. However, these fine-grained techniques are not directly applicable to modular programs.

This talk will describe a context sensitive, fixpoint analysis algorithm aimed at achieving both inter-modular (coarse-grain) and intra-modular (fine-grain) incrementality, solving the problems related to propagation of the fine-grain change information and effects across module boundaries, for additions and deletions in multiple modules.