hydro_lang/sim/
flow.rs

1//! Entrypoint for compiling and running Hydro simulations.
2
3use std::cell::RefCell;
4use std::collections::HashMap;
5use std::panic::RefUnwindSafe;
6use std::rc::Rc;
7
8use dfir_lang::graph::{DfirGraph, FlatGraphBuilder, FlatGraphBuilderOutput};
9use libloading::Library;
10use slotmap::SparseSecondaryMap;
11
12use super::builder::SimBuilder;
13use super::compiled::{CompiledSim, CompiledSimInstance};
14use super::graph::{SimDeploy, SimExternal, SimNode, compile_sim, create_sim_graph_trybuild};
15use crate::compile::ir::HydroRoot;
16use crate::location::LocationKey;
17use crate::location::dynamic::LocationId;
18use crate::prelude::Cluster;
19use crate::sim::graph::SimExternalPortRegistry;
20use crate::staging_util::Invariant;
21
22/// A not-yet-compiled simulator for a Hydro program.
23pub struct SimFlow<'a> {
24    pub(crate) ir: Vec<HydroRoot>,
25
26    /// SimNode for each Process.
27    pub(crate) processes: SparseSecondaryMap<LocationKey, SimNode>,
28    /// SimNode for each Cluster.
29    pub(crate) clusters: SparseSecondaryMap<LocationKey, SimNode>,
30    /// SimExternal for each External.
31    pub(crate) externals: SparseSecondaryMap<LocationKey, SimExternal>,
32
33    /// Max size of each cluster.
34    pub(crate) cluster_max_sizes: SparseSecondaryMap<LocationKey, usize>,
35    /// Handle to state handling `external`s' ports.
36    pub(crate) externals_port_registry: Rc<RefCell<SimExternalPortRegistry>>,
37
38    pub(crate) _phantom: Invariant<'a>,
39}
40
41impl<'a> SimFlow<'a> {
42    /// Sets the maximum size of the given cluster in the simulation.
43    pub fn with_cluster_size<C>(mut self, cluster: &Cluster<'a, C>, max_size: usize) -> Self {
44        self.cluster_max_sizes.insert(cluster.key, max_size);
45        self
46    }
47
48    /// Executes the given closure with a single instance of the compiled simulation.
49    pub fn with_instance<T>(self, thunk: impl FnOnce(CompiledSimInstance) -> T) -> T {
50        self.compiled().with_instance(thunk)
51    }
52
53    /// Uses a fuzzing strategy to explore possible executions of the simulation. The provided
54    /// closure will be repeatedly executed with instances of the Hydro program where the
55    /// batching boundaries, order of messages, and retries are varied.
56    ///
57    /// During development, you should run the test that invokes this function with the `cargo sim`
58    /// command, which will use `libfuzzer` to intelligently explore the execution space. If a
59    /// failure is found, a minimized test case will be produced in a `sim-failures` directory.
60    /// When running the test with `cargo test` (such as in CI), if a reproducer is found it will
61    /// be executed, and if no reproducer is found a small number of random executions will be
62    /// performed.
63    pub fn fuzz(self, thunk: impl AsyncFn() + RefUnwindSafe) {
64        self.compiled().fuzz(thunk)
65    }
66
67    /// Exhaustively searches all possible executions of the simulation. The provided
68    /// closure will be repeatedly executed with instances of the Hydro program where the
69    /// batching boundaries, order of messages, and retries are varied.
70    ///
71    /// Exhaustive searching is feasible when the inputs to the Hydro program are finite and there
72    /// are no dataflow loops that generate infinite messages. Exhaustive searching provides a
73    /// stronger guarantee of correctness than fuzzing, but may take a long time to complete.
74    /// Because no fuzzer is involved, you can run exhaustive tests with `cargo test`.
75    ///
76    /// Returns the number of distinct executions explored.
77    pub fn exhaustive(self, thunk: impl AsyncFnMut() + RefUnwindSafe) -> usize {
78        self.compiled().exhaustive(thunk)
79    }
80
81    /// Compiles the simulation into a dynamically loadable library, and returns a handle to it.
82    pub fn compiled(mut self) -> CompiledSim {
83        use std::collections::BTreeMap;
84
85        use dfir_lang::graph::{eliminate_extra_unions_tees, partition_graph};
86
87        let mut sim_emit = SimBuilder {
88            process_graphs: BTreeMap::new(),
89            cluster_graphs: BTreeMap::new(),
90            process_tick_dfirs: BTreeMap::new(),
91            cluster_tick_dfirs: BTreeMap::new(),
92            extra_stmts_global: vec![],
93            extra_stmts_cluster: BTreeMap::new(),
94            next_hoff_id: 0,
95        };
96
97        // Ensure the default (0) external is always present.
98        self.externals.insert(
99            LocationKey::FIRST,
100            SimExternal {
101                shared_inner: self.externals_port_registry.clone(),
102            },
103        );
104
105        let mut seen_tees_instantiate: HashMap<_, _> = HashMap::new();
106        self.ir.iter_mut().for_each(|leaf| {
107            leaf.compile_network::<SimDeploy>(
108                &mut SparseSecondaryMap::new(),
109                &mut seen_tees_instantiate,
110                &self.processes,
111                &self.clusters,
112                &self.externals,
113                &mut (),
114            );
115        });
116
117        let mut seen_tees = HashMap::new();
118        let mut built_tees = HashMap::new();
119        let mut next_stmt_id = 0;
120        for leaf in &mut self.ir {
121            leaf.emit::<SimDeploy>(
122                &mut sim_emit,
123                &mut seen_tees,
124                &mut built_tees,
125                &mut next_stmt_id,
126            );
127        }
128
129        fn build_graphs(
130            graphs: BTreeMap<LocationId, FlatGraphBuilder>,
131        ) -> BTreeMap<LocationId, DfirGraph> {
132            graphs
133                .into_iter()
134                .map(|(l, g)| {
135                    let FlatGraphBuilderOutput { mut flat_graph, .. } =
136                        g.build().expect("Failed to build DFIR flat graph.");
137                    eliminate_extra_unions_tees(&mut flat_graph);
138                    (
139                        l,
140                        partition_graph(flat_graph).expect("Failed to partition (cycle detected)."),
141                    )
142                })
143                .collect()
144        }
145
146        let process_graphs = build_graphs(sim_emit.process_graphs);
147        let cluster_graphs = build_graphs(sim_emit.cluster_graphs);
148        let process_tick_graphs = build_graphs(sim_emit.process_tick_dfirs);
149        let cluster_tick_graphs = build_graphs(sim_emit.cluster_tick_dfirs);
150
151        #[expect(
152            clippy::disallowed_methods,
153            reason = "nondeterministic iteration order, fine for checks"
154        )]
155        for c in self.clusters.keys() {
156            assert!(
157                self.cluster_max_sizes.contains_key(c),
158                "Cluster {:?} missing max size; call with_cluster_size() before compiled()",
159                c
160            );
161        }
162
163        let (bin, trybuild) = create_sim_graph_trybuild(
164            process_graphs,
165            cluster_graphs,
166            self.cluster_max_sizes,
167            process_tick_graphs,
168            cluster_tick_graphs,
169            sim_emit.extra_stmts_global,
170            sim_emit.extra_stmts_cluster,
171        );
172
173        let out = compile_sim(bin, trybuild).unwrap();
174        let lib = unsafe { Library::new(&out).unwrap() };
175
176        CompiledSim {
177            _path: out,
178            lib,
179            externals_port_registry: self.externals_port_registry.take(),
180        }
181    }
182}
hydro_lang/sim/flow.rs

hydro_lang/sim/
flow.rs
