Utility ADTs and Worklists

include/Utils/ADT/ provides the reusable container and worklist layer used across analyses.

Main components:

• DisjointSet and UnionFind for partition maintenance.

• ImmutableMap, ImmutableSet, and ImmutableTree for persistent data.

• PriorityWorkList and TwoLevelWorkList for solver scheduling.

• TreeStream and related iterator adapters for structured traversal.

• ewah — Compressed bitmap (EWAH) for memory-efficient set representation, commonly used in solver and dataflow contexts.

These headers are used heavily by the dataflow, alias, and solver subsystems.

Choosing a worklist

Use a priority worklist when an analysis has a meaningful ordering that can accelerate convergence, and use a two-level worklist when it needs separate queues for coarse and fine-grained work. Persistent containers are useful for sharing immutable facts across states; avoid them in a hot mutation loop unless their structural sharing outweighs the update cost.

See also Utility Libraries.