Rollup merge of #85583 - cjgillot:no-previous-dg, r=petrochenkov

Get rid of PreviousDepGraph.

Its only role is to access the `SerializedDepGraph`.

compiler/rustc_incremental/src/persist/load.rs

@@ -2,7 +2,7 @@
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::definitions::DefPathTable;
-use rustc_middle::dep_graph::{PreviousDepGraph, SerializedDepGraph, WorkProduct, WorkProductId};
+use rustc_middle::dep_graph::{SerializedDepGraph, WorkProduct, WorkProductId};
 use rustc_middle::ty::query::OnDiskCache;
 use rustc_serialize::opaque::Decoder;
 use rustc_serialize::Decodable;
@@ -22,8 +22,8 @@ pub enum LoadResult<T> {
     Error { message: String },
 }
 
-impl LoadResult<(PreviousDepGraph, WorkProductMap)> {
-    pub fn open(self, sess: &Session) -> (PreviousDepGraph, WorkProductMap) {
+impl LoadResult<(SerializedDepGraph, WorkProductMap)> {
+    pub fn open(self, sess: &Session) -> (SerializedDepGraph, WorkProductMap) {
         match self {
             LoadResult::Error { message } => {
                 sess.warn(&message);
@@ -84,7 +84,7 @@ impl<T> MaybeAsync<T> {
     }
 }
 
-pub type DepGraphFuture = MaybeAsync<LoadResult<(PreviousDepGraph, WorkProductMap)>>;
+pub type DepGraphFuture = MaybeAsync<LoadResult<(SerializedDepGraph, WorkProductMap)>>;
 
 /// Launch a thread and load the dependency graph in the background.
 pub fn load_dep_graph(sess: &Session) -> DepGraphFuture {
@@ -185,7 +185,7 @@ pub fn load_dep_graph(sess: &Session) -> DepGraphFuture {
                 let dep_graph = SerializedDepGraph::decode(&mut decoder)
                     .expect("Error reading cached dep-graph");
 
-                LoadResult::Ok { data: (PreviousDepGraph::new(dep_graph), prev_work_products) }
+                LoadResult::Ok { data: (dep_graph, prev_work_products) }
             }
         }
     }))

compiler/rustc_incremental/src/persist/save.rs

@@ -1,6 +1,6 @@
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::join;
-use rustc_middle::dep_graph::{DepGraph, PreviousDepGraph, WorkProduct, WorkProductId};
+use rustc_middle::dep_graph::{DepGraph, SerializedDepGraph, WorkProduct, WorkProductId};
 use rustc_middle::ty::TyCtxt;
 use rustc_serialize::opaque::{FileEncodeResult, FileEncoder};
 use rustc_serialize::Encodable as RustcEncodable;
@@ -186,7 +186,7 @@ fn encode_query_cache(tcx: TyCtxt<'_>, encoder: &mut FileEncoder) -> FileEncodeR
 
 pub fn build_dep_graph(
     sess: &Session,
-    prev_graph: PreviousDepGraph,
+    prev_graph: SerializedDepGraph,
     prev_work_products: FxHashMap<WorkProductId, WorkProduct>,
 ) -> Option<DepGraph> {
     if sess.opts.incremental.is_none() {

compiler/rustc_middle/src/dep_graph/mod.rs

@@ -18,7 +18,6 @@ crate use dep_node::{make_compile_codegen_unit, make_compile_mono_item};
 pub type DepGraph = rustc_query_system::dep_graph::DepGraph<DepKind>;
 pub type TaskDeps = rustc_query_system::dep_graph::TaskDeps<DepKind>;
 pub type DepGraphQuery = rustc_query_system::dep_graph::DepGraphQuery<DepKind>;
-pub type PreviousDepGraph = rustc_query_system::dep_graph::PreviousDepGraph<DepKind>;
 pub type SerializedDepGraph = rustc_query_system::dep_graph::SerializedDepGraph<DepKind>;
 pub type EdgeFilter = rustc_query_system::dep_graph::debug::EdgeFilter<DepKind>;
 

compiler/rustc_query_system/src/dep_graph/graph.rs

@@ -19,9 +19,8 @@ use std::marker::PhantomData;
 use std::mem;
 use std::sync::atomic::Ordering::Relaxed;
 
-use super::prev::PreviousDepGraph;
 use super::query::DepGraphQuery;
-use super::serialized::{GraphEncoder, SerializedDepNodeIndex};
+use super::serialized::{GraphEncoder, SerializedDepGraph, SerializedDepNodeIndex};
 use super::{DepContext, DepKind, DepNode, HasDepContext, WorkProductId};
 use crate::query::QueryContext;
 
@@ -78,7 +77,7 @@ struct DepGraphData<K: DepKind> {
 
     /// The dep-graph from the previous compilation session. It contains all
     /// nodes and edges as well as all fingerprints of nodes that have them.
-    previous: PreviousDepGraph<K>,
+    previous: SerializedDepGraph<K>,
 
     colors: DepNodeColorMap,
 
@@ -109,7 +108,7 @@ where
 
 impl<K: DepKind> DepGraph<K> {
     pub fn new(
-        prev_graph: PreviousDepGraph<K>,
+        prev_graph: SerializedDepGraph<K>,
         prev_work_products: FxHashMap<WorkProductId, WorkProduct>,
         encoder: FileEncoder,
         record_graph: bool,
@@ -857,7 +856,7 @@ rustc_index::newtype_index! {
 /// For this reason, we avoid storing `DepNode`s more than once as map
 /// keys. The `new_node_to_index` map only contains nodes not in the previous
 /// graph, and we map nodes in the previous graph to indices via a two-step
-/// mapping. `PreviousDepGraph` maps from `DepNode` to `SerializedDepNodeIndex`,
+/// mapping. `SerializedDepGraph` maps from `DepNode` to `SerializedDepNodeIndex`,
 /// and the `prev_index_to_index` vector (which is more compact and faster than
 /// using a map) maps from `SerializedDepNodeIndex` to `DepNodeIndex`.
 ///
@@ -982,7 +981,7 @@ impl<K: DepKind> CurrentDepGraph<K> {
     fn intern_node(
         &self,
         profiler: &SelfProfilerRef,
-        prev_graph: &PreviousDepGraph<K>,
+        prev_graph: &SerializedDepGraph<K>,
         key: DepNode<K>,
         edges: EdgesVec,
         fingerprint: Option<Fingerprint>,
@@ -1080,7 +1079,7 @@ impl<K: DepKind> CurrentDepGraph<K> {
     fn promote_node_and_deps_to_current(
         &self,
         profiler: &SelfProfilerRef,
-        prev_graph: &PreviousDepGraph<K>,
+        prev_graph: &SerializedDepGraph<K>,
         prev_index: SerializedDepNodeIndex,
     ) -> DepNodeIndex {
         self.debug_assert_not_in_new_nodes(prev_graph, prev_index);
@@ -1112,7 +1111,7 @@ impl<K: DepKind> CurrentDepGraph<K> {
     #[inline]
     fn debug_assert_not_in_new_nodes(
         &self,
-        prev_graph: &PreviousDepGraph<K>,
+        prev_graph: &SerializedDepGraph<K>,
         prev_index: SerializedDepNodeIndex,
     ) {
         let node = &prev_graph.index_to_node(prev_index);

compiler/rustc_query_system/src/dep_graph/mod.rs

@@ -1,13 +1,11 @@
 pub mod debug;
 mod dep_node;
 mod graph;
-mod prev;
 mod query;
 mod serialized;
 
 pub use dep_node::{DepNode, DepNodeParams, WorkProductId};
 pub use graph::{hash_result, DepGraph, DepNodeColor, DepNodeIndex, TaskDeps, WorkProduct};
-pub use prev::PreviousDepGraph;
 pub use query::DepGraphQuery;
 pub use serialized::{SerializedDepGraph, SerializedDepNodeIndex};
 

compiler/rustc_query_system/src/dep_graph/serialized.rs

@@ -37,17 +37,19 @@ rustc_index::newtype_index! {
 #[derive(Debug)]
 pub struct SerializedDepGraph<K: DepKind> {
     /// The set of all DepNodes in the graph
-    pub nodes: IndexVec<SerializedDepNodeIndex, DepNode<K>>,
+    nodes: IndexVec<SerializedDepNodeIndex, DepNode<K>>,
     /// The set of all Fingerprints in the graph. Each Fingerprint corresponds to
     /// the DepNode at the same index in the nodes vector.
-    pub fingerprints: IndexVec<SerializedDepNodeIndex, Fingerprint>,
+    fingerprints: IndexVec<SerializedDepNodeIndex, Fingerprint>,
     /// For each DepNode, stores the list of edges originating from that
     /// DepNode. Encoded as a [start, end) pair indexing into edge_list_data,
     /// which holds the actual DepNodeIndices of the target nodes.
-    pub edge_list_indices: IndexVec<SerializedDepNodeIndex, (u32, u32)>,
+    edge_list_indices: IndexVec<SerializedDepNodeIndex, (u32, u32)>,
     /// A flattened list of all edge targets in the graph. Edge sources are
     /// implicit in edge_list_indices.
-    pub edge_list_data: Vec<SerializedDepNodeIndex>,
+    edge_list_data: Vec<SerializedDepNodeIndex>,
+    /// Reciprocal map to `nodes`.
+    index: FxHashMap<DepNode<K>, SerializedDepNodeIndex>,
 }
 
 impl<K: DepKind> Default for SerializedDepGraph<K> {
@@ -57,6 +59,7 @@ impl<K: DepKind> Default for SerializedDepGraph<K> {
             fingerprints: Default::default(),
             edge_list_indices: Default::default(),
             edge_list_data: Default::default(),
+            index: Default::default(),
         }
     }
 }
@@ -67,6 +70,30 @@ impl<K: DepKind> SerializedDepGraph<K> {
         let targets = self.edge_list_indices[source];
         &self.edge_list_data[targets.0 as usize..targets.1 as usize]
     }
+
+    #[inline]
+    pub fn index_to_node(&self, dep_node_index: SerializedDepNodeIndex) -> DepNode<K> {
+        self.nodes[dep_node_index]
+    }
+
+    #[inline]
+    pub fn node_to_index_opt(&self, dep_node: &DepNode<K>) -> Option<SerializedDepNodeIndex> {
+        self.index.get(dep_node).cloned()
+    }
+
+    #[inline]
+    pub fn fingerprint_of(&self, dep_node: &DepNode<K>) -> Option<Fingerprint> {
+        self.index.get(dep_node).map(|&node_index| self.fingerprints[node_index])
+    }
+
+    #[inline]
+    pub fn fingerprint_by_index(&self, dep_node_index: SerializedDepNodeIndex) -> Fingerprint {
+        self.fingerprints[dep_node_index]
+    }
+
+    pub fn node_count(&self) -> usize {
+        self.index.len()
+    }
 }
 
 impl<'a, K: DepKind + Decodable<opaque::Decoder<'a>>> Decodable<opaque::Decoder<'a>>
@@ -121,7 +148,10 @@ impl<'a, K: DepKind + Decodable<opaque::Decoder<'a>>> Decodable<opaque::Decoder<
             })?;
         }
 
-        Ok(SerializedDepGraph { nodes, fingerprints, edge_list_indices, edge_list_data })
+        let index: FxHashMap<_, _> =
+            nodes.iter_enumerated().map(|(idx, &dep_node)| (dep_node, idx)).collect();
+
+        Ok(SerializedDepGraph { nodes, fingerprints, edge_list_indices, edge_list_data, index })
     }
 }