Struct LivenessResult 

pub struct LivenessResult { /* private fields */ }

Liveness analysis result for a whole program.

For each user-defined function, stores a per-statement live_after set: live_after[i] is the set of variables live immediately after top-level statement i in that function’s body.

Used by codegen to decide when an argument can be moved into a call instead of cloned: if a variable is not live after the call statement, the old value is never read again and ownership can be transferred.

Implementations

impl LivenessResult

pub fn analyze(stmts: &[Stmt<'_>]) -> Self

Compute liveness for every FunctionDef in stmts.

Algorithm: backward dataflow over the top-level statement list of each function body. Return is treated as a terminator — variables used in subsequent (dead-code) statements do not affect liveness before the Return.

pub fn is_live_after( &self, fn_sym: Symbol, stmt_idx: usize, var: Symbol, ) -> bool

Returns true if var is live immediately after top-level statement stmt_idx in function fn_sym.

Returns false for unknown functions, out-of-bounds indices, or when the variable is definitely dead.

pub fn live_after(&self, fn_sym: Symbol, stmt_idx: usize) -> &HashSet<Symbol>

Returns the live-after set for statement stmt_idx in fn_sym.

Returns a reference to an empty set when the function or index is unknown.