Trait rustc_mir_dataflow::GenKill

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pub trait GenKill<T> {
    // Required methods
    fn gen(&mut self, elem: T);
    fn kill(&mut self, elem: T);

    // Provided methods
    fn gen_all(&mut self, elems: impl IntoIterator<Item = T>) { ... }
    fn kill_all(&mut self, elems: impl IntoIterator<Item = T>) { ... }
}

Expand description

The legal operations for a transfer function in a gen/kill problem.

This abstraction exists because there are two different contexts in which we call the methods in GenKillAnalysis. Sometimes we need to store a single transfer function that can be efficiently applied multiple times, such as when computing the cumulative transfer function for each block. These cases require a GenKillSet, which in turn requires two BitSets of storage. Oftentimes, however, we only need to apply an effect once. In these cases, it is more efficient to pass the BitSet representing the state vector directly into the *_effect methods as opposed to building up a GenKillSet and then throwing it away.