-//! A framework for expressing dataflow problems.
+//! A framework that can express both [gen-kill] and generic dataflow problems.
+//!
+//! There is another interface for dataflow in the compiler in `librustc_mir/dataflow/mod.rs`. The
+//! interface in this module will eventually [replace that one][design-meeting].
+//!
+//! To actually use this framework, you must implement either the `Analysis` or the
+//! `GenKillAnalysis` trait. If your transfer function can be expressed with only gen/kill
+//! operations, prefer `GenKillAnalysis` as it will perform better. Create an `Engine` using the
+//! appropriate constructor and call `iterate_to_fixpoint`. You can use a `ResultsCursor` to
+//! inspect the fixpoint solution to your dataflow problem.
+//!
+//! ```ignore(cross-crate-imports)
+//! fn do_my_analysis(tcx: TyCtxt<'tcx>, body: &mir::Body<'tcx>, did: DefId) {
+//! let analysis = MyAnalysis::new();
+//!
+//! // If `MyAnalysis` implements `GenKillAnalysis`.
+//! let results = Engine::new_gen_kill(tcx, body, did, analysis).iterate_to_fixpoint();
+//!
+//! // If `MyAnalysis` implements `Analysis`.
+//! // let results = Engine::new_generic(tcx, body, did, analysis).iterate_to_fixpoint();
+//!
+//! let mut cursor = ResultsCursor::new(body, results);
+//!
+//! for (_, statement_index) in body.block_data[START_BLOCK].statements.iter_enumerated() {
+//! cursor.seek_after(Location { block: START_BLOCK, statement_index });
+//! let state = cursor.get();
+//! println!("{:?}", state);
+//! }
+//! }
+//! ```
+//!
+//! [gen-kill]: https://en.wikipedia.org/wiki/Data-flow_analysis#Bit_vector_problems
+//! [design-meeting]https://github.com/rust-lang/compiler-team/issues/202
use std::io;
}
}
-/// Define a dataflow problem with an arbitrarily complex transfer function.
+/// A dataflow problem with an arbitrarily complex transfer function.
pub trait Analysis<'tcx>: AnalysisDomain<'tcx> {
/// Updates the current dataflow state with the effect of evaluating a statement.
fn apply_statement_effect(
);
}
-/// Define a gen/kill dataflow problem.
+/// A gen/kill dataflow problem.
///
/// Each method in this trait has a corresponding one in `Analysis`. However, these methods only
/// allow modification of the dataflow state via "gen" and "kill" operations. By defining transfer