Rollup merge of #152844 - Zalathar:retain-dep-graph, r=JonathanBrouwer

Rename `DepGraphQuery` to `RetainedDepGraph`

This is a revised subset of #152836 that only performs an internal renaming, and does not touch the `-Zquery-dep-graph` flag.

The new name and comments for `RetainedDepGraph` should hopefully do a better job of communicating that it is not used in normal compiler operation, even in incremental mode.

Author: JonathanBrouwer

compiler/rustc_incremental/src/assert_dep_graph.rs

@@ -44,7 +44,7 @@ use rustc_hir::attrs::AttributeKind;
 use rustc_hir::def_id::{CRATE_DEF_ID, DefId, LocalDefId};
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_middle::bug;
-use rustc_middle::dep_graph::{DepGraphQuery, DepKind, DepNode, DepNodeFilter, EdgeFilter};
+use rustc_middle::dep_graph::{DepKind, DepNode, DepNodeFilter, EdgeFilter, RetainedDepGraph};
 use rustc_middle::hir::nested_filter;
 use rustc_middle::ty::TyCtxt;
 use rustc_span::{Span, Symbol, sym};
@@ -57,7 +57,7 @@ use crate::errors;
 pub(crate) fn assert_dep_graph(tcx: TyCtxt<'_>) {
     tcx.dep_graph.with_ignore(|| {
         if tcx.sess.opts.unstable_opts.dump_dep_graph {
-            tcx.dep_graph.with_query(dump_graph);
+            tcx.dep_graph.with_retained_dep_graph(dump_graph);
         }
 
         if !tcx.sess.opts.unstable_opts.query_dep_graph {
@@ -184,7 +184,7 @@ fn check_paths<'tcx>(tcx: TyCtxt<'tcx>, if_this_changed: &Sources, then_this_wou
         }
         return;
     }
-    tcx.dep_graph.with_query(|query| {
+    tcx.dep_graph.with_retained_dep_graph(|query| {
         for &(_, source_def_id, ref source_dep_node) in if_this_changed {
             let dependents = query.transitive_predecessors(source_dep_node);
             for &(target_span, ref target_pass, _, ref target_dep_node) in then_this_would_need {
@@ -202,21 +202,21 @@ fn check_paths<'tcx>(tcx: TyCtxt<'tcx>, if_this_changed: &Sources, then_this_wou
     });
 }
 
-fn dump_graph(query: &DepGraphQuery) {
+fn dump_graph(graph: &RetainedDepGraph) {
     let path: String = env::var("RUST_DEP_GRAPH").unwrap_or_else(|_| "dep_graph".to_string());
 
     let nodes = match env::var("RUST_DEP_GRAPH_FILTER") {
         Ok(string) => {
             // Expect one of: "-> target", "source -> target", or "source ->".
             let edge_filter =
                 EdgeFilter::new(&string).unwrap_or_else(|e| bug!("invalid filter: {}", e));
-            let sources = node_set(query, &edge_filter.source);
-            let targets = node_set(query, &edge_filter.target);
-            filter_nodes(query, &sources, &targets)
+            let sources = node_set(graph, &edge_filter.source);
+            let targets = node_set(graph, &edge_filter.target);
+            filter_nodes(graph, &sources, &targets)
         }
-        Err(_) => query.nodes().into_iter().map(|n| n.kind).collect(),
+        Err(_) => graph.nodes().into_iter().map(|n| n.kind).collect(),
     };
-    let edges = filter_edges(query, &nodes);
+    let edges = filter_edges(graph, &nodes);
 
     {
         // dump a .txt file with just the edges:
@@ -279,51 +279,51 @@ impl<'a> dot::Labeller<'a> for GraphvizDepGraph {
 // Given an optional filter like `"x,y,z"`, returns either `None` (no
 // filter) or the set of nodes whose labels contain all of those
 // substrings.
-fn node_set<'q>(
-    query: &'q DepGraphQuery,
+fn node_set<'g>(
+    graph: &'g RetainedDepGraph,
     filter: &DepNodeFilter,
-) -> Option<FxIndexSet<&'q DepNode>> {
+) -> Option<FxIndexSet<&'g DepNode>> {
     debug!("node_set(filter={:?})", filter);
 
     if filter.accepts_all() {
         return None;
     }
 
-    Some(query.nodes().into_iter().filter(|n| filter.test(n)).collect())
+    Some(graph.nodes().into_iter().filter(|n| filter.test(n)).collect())
 }
 
-fn filter_nodes<'q>(
-    query: &'q DepGraphQuery,
-    sources: &Option<FxIndexSet<&'q DepNode>>,
-    targets: &Option<FxIndexSet<&'q DepNode>>,
+fn filter_nodes<'g>(
+    graph: &'g RetainedDepGraph,
+    sources: &Option<FxIndexSet<&'g DepNode>>,
+    targets: &Option<FxIndexSet<&'g DepNode>>,
 ) -> FxIndexSet<DepKind> {
     if let Some(sources) = sources {
         if let Some(targets) = targets {
-            walk_between(query, sources, targets)
+            walk_between(graph, sources, targets)
         } else {
-            walk_nodes(query, sources, OUTGOING)
+            walk_nodes(graph, sources, OUTGOING)
         }
     } else if let Some(targets) = targets {
-        walk_nodes(query, targets, INCOMING)
+        walk_nodes(graph, targets, INCOMING)
     } else {
-        query.nodes().into_iter().map(|n| n.kind).collect()
+        graph.nodes().into_iter().map(|n| n.kind).collect()
     }
 }
 
-fn walk_nodes<'q>(
-    query: &'q DepGraphQuery,
-    starts: &FxIndexSet<&'q DepNode>,
+fn walk_nodes<'g>(
+    graph: &'g RetainedDepGraph,
+    starts: &FxIndexSet<&'g DepNode>,
     direction: Direction,
 ) -> FxIndexSet<DepKind> {
     let mut set = FxIndexSet::default();
     for &start in starts {
         debug!("walk_nodes: start={:?} outgoing?={:?}", start, direction == OUTGOING);
         if set.insert(start.kind) {
-            let mut stack = vec![query.indices[start]];
+            let mut stack = vec![graph.indices[start]];
             while let Some(index) = stack.pop() {
-                for (_, edge) in query.graph.adjacent_edges(index, direction) {
+                for (_, edge) in graph.inner.adjacent_edges(index, direction) {
                     let neighbor_index = edge.source_or_target(direction);
-                    let neighbor = query.graph.node_data(neighbor_index);
+                    let neighbor = graph.inner.node_data(neighbor_index);
                     if set.insert(neighbor.kind) {
                         stack.push(neighbor_index);
                     }
@@ -334,10 +334,10 @@ fn walk_nodes<'q>(
     set
 }
 
-fn walk_between<'q>(
-    query: &'q DepGraphQuery,
-    sources: &FxIndexSet<&'q DepNode>,
-    targets: &FxIndexSet<&'q DepNode>,
+fn walk_between<'g>(
+    graph: &'g RetainedDepGraph,
+    sources: &FxIndexSet<&'g DepNode>,
+    targets: &FxIndexSet<&'g DepNode>,
 ) -> FxIndexSet<DepKind> {
     // This is a bit tricky. We want to include a node only if it is:
     // (a) reachable from a source and (b) will reach a target. And we
@@ -352,27 +352,27 @@ fn walk_between<'q>(
         Excluded,
     }
 
-    let mut node_states = vec![State::Undecided; query.graph.len_nodes()];
+    let mut node_states = vec![State::Undecided; graph.inner.len_nodes()];
 
     for &target in targets {
-        node_states[query.indices[target].0] = State::Included;
+        node_states[graph.indices[target].0] = State::Included;
     }
 
-    for source in sources.iter().map(|&n| query.indices[n]) {
-        recurse(query, &mut node_states, source);
+    for source in sources.iter().map(|&n| graph.indices[n]) {
+        recurse(graph, &mut node_states, source);
     }
 
-    return query
+    return graph
         .nodes()
         .into_iter()
         .filter(|&n| {
-            let index = query.indices[n];
+            let index = graph.indices[n];
             node_states[index.0] == State::Included
         })
         .map(|n| n.kind)
         .collect();
 
-    fn recurse(query: &DepGraphQuery, node_states: &mut [State], node: NodeIndex) -> bool {
+    fn recurse(graph: &RetainedDepGraph, node_states: &mut [State], node: NodeIndex) -> bool {
         match node_states[node.0] {
             // known to reach a target
             State::Included => return true,
@@ -388,8 +388,8 @@ fn walk_between<'q>(
 
         node_states[node.0] = State::Deciding;
 
-        for neighbor_index in query.graph.successor_nodes(node) {
-            if recurse(query, node_states, neighbor_index) {
+        for neighbor_index in graph.inner.successor_nodes(node) {
+            if recurse(graph, node_states, neighbor_index) {
                 node_states[node.0] = State::Included;
             }
         }
@@ -405,8 +405,8 @@ fn walk_between<'q>(
     }
 }
 
-fn filter_edges(query: &DepGraphQuery, nodes: &FxIndexSet<DepKind>) -> Vec<(DepKind, DepKind)> {
-    let uniq: FxIndexSet<_> = query
+fn filter_edges(graph: &RetainedDepGraph, nodes: &FxIndexSet<DepKind>) -> Vec<(DepKind, DepKind)> {
+    let uniq: FxIndexSet<_> = graph
         .edges()
         .into_iter()
         .map(|(s, t)| (s.kind, t.kind))

compiler/rustc_middle/src/dep_graph/graph.rs

@@ -21,7 +21,7 @@ use tracing::{debug, instrument};
 #[cfg(debug_assertions)]
 use {super::debug::EdgeFilter, std::env};
 
-use super::query::DepGraphQuery;
+use super::retained::RetainedDepGraph;
 use super::serialized::{GraphEncoder, SerializedDepGraph, SerializedDepNodeIndex};
 use super::{DepKind, DepNode, WorkProductId, read_deps, with_deps};
 use crate::dep_graph::edges::EdgesVec;
@@ -191,9 +191,9 @@ impl DepGraph {
         self.data.is_some()
     }
 
-    pub fn with_query(&self, f: impl Fn(&DepGraphQuery)) {
+    pub fn with_retained_dep_graph(&self, f: impl Fn(&RetainedDepGraph)) {
         if let Some(data) = &self.data {
-            data.current.encoder.with_query(f)
+            data.current.encoder.with_retained_dep_graph(f)
         }
     }
 

compiler/rustc_middle/src/dep_graph/mod.rs

@@ -10,7 +10,7 @@ pub use self::graph::{
     WorkProductMap, hash_result,
 };
 use self::graph::{MarkFrame, print_markframe_trace};
-pub use self::query::DepGraphQuery;
+pub use self::retained::RetainedDepGraph;
 pub use self::serialized::{SerializedDepGraph, SerializedDepNodeIndex};
 pub use crate::dep_graph::debug::{DepNodeFilter, EdgeFilter};
 use crate::ty::print::with_reduced_queries;
@@ -21,7 +21,7 @@ pub(crate) mod dep_node;
 mod dep_node_key;
 mod edges;
 mod graph;
-mod query;
+mod retained;
 mod serialized;
 
 /// Describes the contents of the fingerprint generated by a given query.

…iler/rustc_middle/src/dep_graph/query.rs …r/rustc_middle/src/dep_graph/retained.rscompiler/rustc_middle/src/dep_graph/query.rs renamed to compiler/rustc_middle/src/dep_graph/retained.rs compiler/rustc_middle/src/dep_graph/query.rs renamed to compiler/rustc_middle/src/dep_graph/retained.rs

@@ -4,54 +4,60 @@ use rustc_index::IndexVec;
 
 use super::{DepNode, DepNodeIndex};
 
-pub struct DepGraphQuery {
-    pub graph: LinkedGraph<DepNode, ()>,
+/// An in-memory copy of the current session's query dependency graph, which
+/// is only enabled when `-Zquery-dep-graph` is set (for debugging/testing).
+///
+/// Normally, dependencies recorded during the current session are written to
+/// disk and then forgotten, to avoid wasting memory on information that is
+/// not needed when the compiler is working correctly.
+pub struct RetainedDepGraph {
+    pub inner: LinkedGraph<DepNode, ()>,
     pub indices: FxHashMap<DepNode, NodeIndex>,
     pub dep_index_to_index: IndexVec<DepNodeIndex, Option<NodeIndex>>,
 }
 
-impl DepGraphQuery {
-    pub fn new(prev_node_count: usize) -> DepGraphQuery {
+impl RetainedDepGraph {
+    pub fn new(prev_node_count: usize) -> Self {
         let node_count = prev_node_count + prev_node_count / 4;
         let edge_count = 6 * node_count;
 
-        let graph = LinkedGraph::with_capacity(node_count, edge_count);
+        let inner = LinkedGraph::with_capacity(node_count, edge_count);
         let indices = FxHashMap::default();
         let dep_index_to_index = IndexVec::new();
 
-        DepGraphQuery { graph, indices, dep_index_to_index }
+        Self { inner, indices, dep_index_to_index }
     }
 
     pub fn push(&mut self, index: DepNodeIndex, node: DepNode, edges: &[DepNodeIndex]) {
-        let source = self.graph.add_node(node);
+        let source = self.inner.add_node(node);
         self.dep_index_to_index.insert(index, source);
         self.indices.insert(node, source);
 
         for &target in edges.iter() {
             // We may miss the edges that are pushed while the `DepGraphQuery` is being accessed.
             // Skip them to issues.
             if let Some(&Some(target)) = self.dep_index_to_index.get(target) {
-                self.graph.add_edge(source, target, ());
+                self.inner.add_edge(source, target, ());
             }
         }
     }
 
     pub fn nodes(&self) -> Vec<&DepNode> {
-        self.graph.all_nodes().iter().map(|n| &n.data).collect()
+        self.inner.all_nodes().iter().map(|n| &n.data).collect()
     }
 
     pub fn edges(&self) -> Vec<(&DepNode, &DepNode)> {
-        self.graph
+        self.inner
             .all_edges()
             .iter()
             .map(|edge| (edge.source(), edge.target()))
-            .map(|(s, t)| (self.graph.node_data(s), self.graph.node_data(t)))
+            .map(|(s, t)| (self.inner.node_data(s), self.inner.node_data(t)))
             .collect()
     }
 
     fn reachable_nodes(&self, node: &DepNode, direction: Direction) -> Vec<&DepNode> {
         if let Some(&index) = self.indices.get(node) {
-            self.graph.depth_traverse(index, direction).map(|s| self.graph.node_data(s)).collect()
+            self.inner.depth_traverse(index, direction).map(|s| self.inner.node_data(s)).collect()
         } else {
             vec![]
         }