Removed use of iteration through a HashMap/HashSet in rustc_incremental and replaced with IndexMap/IndexSet

compiler/rustc_incremental/src/assert_dep_graph.rs

@@ -35,7 +35,7 @@
 
 use crate::errors;
 use rustc_ast as ast;
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::FxIndexSet;
 use rustc_data_structures::graph::implementation::{Direction, NodeIndex, INCOMING, OUTGOING};
 use rustc_graphviz as dot;
 use rustc_hir as hir;
@@ -258,7 +258,7 @@ fn dump_graph(query: &DepGraphQuery) {
 }
 
 #[allow(missing_docs)]
-pub struct GraphvizDepGraph(FxHashSet<DepKind>, Vec<(DepKind, DepKind)>);
+pub struct GraphvizDepGraph(FxIndexSet<DepKind>, Vec<(DepKind, DepKind)>);
 
 impl<'a> dot::GraphWalk<'a> for GraphvizDepGraph {
     type Node = DepKind;
@@ -303,7 +303,7 @@ impl<'a> dot::Labeller<'a> for GraphvizDepGraph {
 fn node_set<'q>(
     query: &'q DepGraphQuery,
     filter: &DepNodeFilter,
-) -> Option<FxHashSet<&'q DepNode>> {
+) -> Option<FxIndexSet<&'q DepNode>> {
     debug!("node_set(filter={:?})", filter);
 
     if filter.accepts_all() {
@@ -315,9 +315,9 @@ fn node_set<'q>(
 
 fn filter_nodes<'q>(
     query: &'q DepGraphQuery,
-    sources: &Option<FxHashSet<&'q DepNode>>,
-    targets: &Option<FxHashSet<&'q DepNode>>,
-) -> FxHashSet<DepKind> {
+    sources: &Option<FxIndexSet<&'q DepNode>>,
+    targets: &Option<FxIndexSet<&'q DepNode>>,
+) -> FxIndexSet<DepKind> {
     if let Some(sources) = sources {
         if let Some(targets) = targets {
             walk_between(query, sources, targets)
@@ -333,10 +333,10 @@ fn filter_nodes<'q>(
 
 fn walk_nodes<'q>(
     query: &'q DepGraphQuery,
-    starts: &FxHashSet<&'q DepNode>,
+    starts: &FxIndexSet<&'q DepNode>,
     direction: Direction,
-) -> FxHashSet<DepKind> {
-    let mut set = FxHashSet::default();
+) -> FxIndexSet<DepKind> {
+    let mut set = FxIndexSet::default();
     for &start in starts {
         debug!("walk_nodes: start={:?} outgoing?={:?}", start, direction == OUTGOING);
         if set.insert(start.kind) {
@@ -357,9 +357,9 @@ fn walk_nodes<'q>(
 
 fn walk_between<'q>(
     query: &'q DepGraphQuery,
-    sources: &FxHashSet<&'q DepNode>,
-    targets: &FxHashSet<&'q DepNode>,
-) -> FxHashSet<DepKind> {
+    sources: &FxIndexSet<&'q DepNode>,
+    targets: &FxIndexSet<&'q 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
     // have to be careful about cycles etc. Luckily efficiency is not
@@ -426,8 +426,8 @@ fn walk_between<'q>(
     }
 }
 
-fn filter_edges(query: &DepGraphQuery, nodes: &FxHashSet<DepKind>) -> Vec<(DepKind, DepKind)> {
-    let uniq: FxHashSet<_> = query
+fn filter_edges(query: &DepGraphQuery, nodes: &FxIndexSet<DepKind>) -> Vec<(DepKind, DepKind)> {
+    let uniq: FxIndexSet<_> = query
         .edges()
         .into_iter()
         .map(|(s, t)| (s.kind, t.kind))

compiler/rustc_incremental/src/assert_module_sources.rs

@@ -24,7 +24,7 @@
 
 use crate::errors;
 use rustc_ast as ast;
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::FxIndexSet;
 use rustc_hir::def_id::LOCAL_CRATE;
 use rustc_middle::mir::mono::CodegenUnitNameBuilder;
 use rustc_middle::ty::TyCtxt;
@@ -52,7 +52,7 @@ pub fn assert_module_sources(tcx: TyCtxt<'_>) {
 
 struct AssertModuleSource<'tcx> {
     tcx: TyCtxt<'tcx>,
-    available_cgus: FxHashSet<Symbol>,
+    available_cgus: FxIndexSet<Symbol>,
 }
 
 impl<'tcx> AssertModuleSource<'tcx> {

compiler/rustc_incremental/src/lib.rs

@@ -4,7 +4,6 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(never_type)]
 #![recursion_limit = "256"]
-#![allow(rustc::potential_query_instability)]
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
 

compiler/rustc_incremental/src/persist/dirty_clean.rs

@@ -21,7 +21,7 @@
 
 use crate::errors;
 use rustc_ast::{self as ast, Attribute, NestedMetaItem};
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::intravisit;
 use rustc_hir::Node as HirNode;
@@ -125,7 +125,7 @@ const LABELS_ADT: &[&[&str]] = &[BASE_HIR, BASE_STRUCT];
 //
 //     type_of for these.
 
-type Labels = FxHashSet<String>;
+type Labels = FxIndexSet<String>;
 
 /// Represents the requested configuration by rustc_clean/dirty
 struct Assertion {

compiler/rustc_incremental/src/persist/fs.rs

@@ -104,7 +104,7 @@
 //! implemented.
 
 use crate::errors;
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet};
 use rustc_data_structures::svh::Svh;
 use rustc_data_structures::{base_n, flock};
 use rustc_errors::ErrorGuaranteed;
@@ -635,8 +635,8 @@ pub fn garbage_collect_session_directories(sess: &Session) -> io::Result<()> {
 
     // First do a pass over the crate directory, collecting lock files and
     // session directories
-    let mut session_directories = FxHashSet::default();
-    let mut lock_files = FxHashSet::default();
+    let mut session_directories = FxIndexSet::default();
+    let mut lock_files = FxIndexSet::default();
 
     for dir_entry in crate_directory.read_dir()? {
         let Ok(dir_entry) = dir_entry else {
@@ -659,7 +659,7 @@ pub fn garbage_collect_session_directories(sess: &Session) -> io::Result<()> {
     }
 
     // Now map from lock files to session directories
-    let lock_file_to_session_dir: FxHashMap<String, Option<String>> = lock_files
+    let lock_file_to_session_dir: FxIndexMap<String, Option<String>> = lock_files
         .into_iter()
         .map(|lock_file_name| {
             assert!(lock_file_name.ends_with(LOCK_FILE_EXT));
@@ -705,7 +705,7 @@ pub fn garbage_collect_session_directories(sess: &Session) -> io::Result<()> {
     }
 
     // Filter out `None` directories
-    let lock_file_to_session_dir: FxHashMap<String, String> = lock_file_to_session_dir
+    let lock_file_to_session_dir: FxIndexMap<String, String> = lock_file_to_session_dir
         .into_iter()
         .filter_map(|(lock_file_name, directory_name)| directory_name.map(|n| (lock_file_name, n)))
         .collect();
@@ -846,7 +846,7 @@ fn delete_old(sess: &Session, path: &Path) {
 
 fn all_except_most_recent(
     deletion_candidates: Vec<(SystemTime, PathBuf, Option<flock::Lock>)>,
-) -> FxHashMap<PathBuf, Option<flock::Lock>> {
+) -> FxIndexMap<PathBuf, Option<flock::Lock>> {
     let most_recent = deletion_candidates.iter().map(|&(timestamp, ..)| timestamp).max();
 
     if let Some(most_recent) = most_recent {
@@ -856,7 +856,7 @@ fn all_except_most_recent(
             .map(|(_, path, lock)| (path, lock))
             .collect()
     } else {
-        FxHashMap::default()
+        FxIndexMap::default()
     }
 }
 

compiler/rustc_incremental/src/persist/load.rs

@@ -1,7 +1,7 @@
 //! Code to save/load the dep-graph from files.
 
 use crate::errors;
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::memmap::Mmap;
 use rustc_middle::dep_graph::{SerializedDepGraph, WorkProduct, WorkProductId};
 use rustc_middle::query::on_disk_cache::OnDiskCache;
@@ -16,7 +16,7 @@ use super::file_format;
 use super::fs::*;
 use super::work_product;
 
-type WorkProductMap = FxHashMap<WorkProductId, WorkProduct>;
+type WorkProductMap = FxIndexMap<WorkProductId, WorkProduct>;
 
 #[derive(Debug)]
 /// Represents the result of an attempt to load incremental compilation data.
@@ -147,7 +147,7 @@ pub fn load_dep_graph(sess: &Session) -> DepGraphFuture {
     let report_incremental_info = sess.opts.unstable_opts.incremental_info;
     let expected_hash = sess.opts.dep_tracking_hash(false);
 
-    let mut prev_work_products = FxHashMap::default();
+    let mut prev_work_products = FxIndexMap::default();
 
     // If we are only building with -Zquery-dep-graph but without an actual
     // incr. comp. session directory, we skip this. Otherwise we'd fail

compiler/rustc_incremental/src/persist/save.rs

@@ -1,5 +1,5 @@
 use crate::errors;
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::sync::join;
 use rustc_middle::dep_graph::{DepGraph, SerializedDepGraph, WorkProduct, WorkProductId};
 use rustc_middle::ty::TyCtxt;
@@ -79,7 +79,7 @@ pub fn save_dep_graph(tcx: TyCtxt<'_>) {
 pub fn save_work_product_index(
     sess: &Session,
     dep_graph: &DepGraph,
-    new_work_products: FxHashMap<WorkProductId, WorkProduct>,
+    new_work_products: FxIndexMap<WorkProductId, WorkProduct>,
 ) {
     if sess.opts.incremental.is_none() {
         return;
@@ -119,7 +119,7 @@ pub fn save_work_product_index(
 }
 
 fn encode_work_product_index(
-    work_products: &FxHashMap<WorkProductId, WorkProduct>,
+    work_products: &FxIndexMap<WorkProductId, WorkProduct>,
     encoder: &mut FileEncoder,
 ) {
     let serialized_products: Vec<_> = work_products
@@ -146,7 +146,7 @@ fn encode_query_cache(tcx: TyCtxt<'_>, encoder: FileEncoder) -> FileEncodeResult
 pub fn build_dep_graph(
     sess: &Session,
     prev_graph: SerializedDepGraph,
-    prev_work_products: FxHashMap<WorkProductId, WorkProduct>,
+    prev_work_products: FxIndexMap<WorkProductId, WorkProduct>,
 ) -> Option<DepGraph> {
     if sess.opts.incremental.is_none() {
         // No incremental compilation.

compiler/rustc_incremental/src/persist/work_product.rs

@@ -4,7 +4,7 @@
 
 use crate::errors;
 use crate::persist::fs::*;
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::FxIndexMap;
 use rustc_fs_util::link_or_copy;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
 use rustc_session::Session;
@@ -20,7 +20,7 @@ pub fn copy_cgu_workproduct_to_incr_comp_cache_dir(
     debug!(?cgu_name, ?files);
     sess.opts.incremental.as_ref()?;
 
-    let mut saved_files = FxHashMap::default();
+    let mut saved_files = FxIndexMap::default();
     for (ext, path) in files {
         let file_name = format!("{cgu_name}.{ext}");
         let path_in_incr_dir = in_incr_comp_dir_sess(sess, &file_name);