Struct DominatorTree 

pub struct DominatorTree<N: Copy + Hash + Eq, S: BuildHasher + Default = FxBuildHasher> { /* private fields */ }

Dominator tree for a reachable subgraph.

The immediate-dominator map is computed eagerly by compute_dominators. Full dominator sets and the children map are computed lazily on first access and then cached.

The tree is generic over the hasher S used for its internal, node-keyed maps — pinned to the source graph’s Graph::Hasher by compute_dominators — rather than hardcoding a concrete one. It defaults to FxBuildHasher so the common DominatorTree<NodeId> spelling keeps the fast, deterministic hasher that graph consumers (e.g. qcode’s Context) select.

Implementations

impl<N: Copy + Hash + Eq, S: BuildHasher + Default> DominatorTree<N, S>

pub fn root(&self) -> N

The root of the dominator tree (the CFG entry node).

pub fn immediate_dominator(&self, node: N) -> Option<N>

Returns the immediate dominator of node, or None if node is the root or was not in the analyzed subgraph.

pub fn children_of(&self, node: N) -> &[N]

Returns the children of node in the dominator tree — the nodes for which node is the immediate dominator.

pub fn dominates(&self, dominator: N, node: N) -> bool

Returns true if dominator dominates node.

Every node dominates itself. Triggers lazy set computation on first call.

pub fn dominator_set(&self, node: N) -> Option<&HashSet<N, S>>

Returns the set of all nodes that dominate node, or None if node was not in the analyzed subgraph.

Triggers lazy set computation on first call.

pub fn dominator_frontier(&self) -> &HashMap<N, HashSet<N, S>, S>

Returns the dominator frontier for every node in the analyzed subgraph.

The dominator frontier of n is the set of nodes y such that n dominates a predecessor of y but does not strictly dominate y. Frontiers are used by SSA construction to determine phi-node placement.

Computed lazily on first call using the Cytron et al. algorithm.