crates is already deterministic

rust-lang · Sep 21, 2021 · 01bcddb · 01bcddb
1 parent 5b9cc20
commit 01bcddb
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Showing 3 changed files with 29 additions and 43 deletions.
diff --git a/compiler/rustc_metadata/src/dependency_format.rs b/compiler/rustc_metadata/src/dependency_format.rs
@@ -277,7 +277,7 @@ fn attempt_static(tcx: TyCtxt<'_>) -> Option<DependencyList> {
     let all_crates_available_as_rlib = tcx
         .crates(())
         .iter()
-        .cloned()
+        .copied()
         .filter_map(|cnum| {
             if tcx.dep_kind(cnum).macros_only() {
                 return None;
@@ -291,10 +291,11 @@ fn attempt_static(tcx: TyCtxt<'_>) -> Option<DependencyList> {
 
     // All crates are available in an rlib format, so we're just going to link
     // everything in explicitly so long as it's actually required.
-    let last_crate = tcx.crates(()).len();
-    let mut ret = (1..last_crate + 1)
-        .map(|cnum| {
-            if tcx.dep_kind(CrateNum::new(cnum)) == CrateDepKind::Explicit {
+    let mut ret = tcx
+        .crates(())
+        .iter()
+        .map(|&cnum| {
+            if tcx.dep_kind(cnum) == CrateDepKind::Explicit {
                 Linkage::Static
             } else {
                 Linkage::NotLinked

diff --git a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
@@ -304,17 +304,7 @@ pub fn provide(providers: &mut Providers) {
             // traversal, but not globally minimal across all crates.
             let bfs_queue = &mut VecDeque::new();
 
-            // Preferring shortest paths alone does not guarantee a
-            // deterministic result; so sort by crate num to avoid
-            // hashtable iteration non-determinism. This only makes
-            // things as deterministic as crate-nums assignment is,
-            // which is to say, its not deterministic in general. But
-            // we believe that libstd is consistently assigned crate
-            // num 1, so it should be enough to resolve #46112.
-            let mut crates: Vec<CrateNum> = (*tcx.crates(())).to_owned();
-            crates.sort();
-
-            for &cnum in crates.iter() {
+            for &cnum in tcx.crates(()) {
                 // Ignore crates without a corresponding local `extern crate` item.
                 if tcx.missing_extern_crate_item(cnum) {
                     continue;
@@ -323,35 +313,31 @@ pub fn provide(providers: &mut Providers) {
                 bfs_queue.push_back(DefId { krate: cnum, index: CRATE_DEF_INDEX });
             }
 
-            // (restrict scope of mutable-borrow of `visible_parent_map`)
-            {
-                let visible_parent_map = &mut visible_parent_map;
-                let mut add_child = |bfs_queue: &mut VecDeque<_>, child: &Export, parent: DefId| {
-                    if child.vis != ty::Visibility::Public {
-                        return;
-                    }
+            let mut add_child = |bfs_queue: &mut VecDeque<_>, child: &Export, parent: DefId| {
+                if child.vis != ty::Visibility::Public {
+                    return;
+                }
 
-                    if let Some(child) = child.res.opt_def_id() {
-                        match visible_parent_map.entry(child) {
-                            Entry::Occupied(mut entry) => {
-                                // If `child` is defined in crate `cnum`, ensure
-                                // that it is mapped to a parent in `cnum`.
-                                if child.is_local() && entry.get().is_local() {
-                                    entry.insert(parent);
-                                }
-                            }
-                            Entry::Vacant(entry) => {
+                if let Some(child) = child.res.opt_def_id() {
+                    match visible_parent_map.entry(child) {
+                        Entry::Occupied(mut entry) => {
+                            // If `child` is defined in crate `cnum`, ensure
+                            // that it is mapped to a parent in `cnum`.
+                            if child.is_local() && entry.get().is_local() {
                                 entry.insert(parent);
-                                bfs_queue.push_back(child);
                             }
                         }
+                        Entry::Vacant(entry) => {
+                            entry.insert(parent);
+                            bfs_queue.push_back(child);
+                        }
                     }
-                };
+                }
+            };
 
-                while let Some(def) = bfs_queue.pop_front() {
-                    for child in tcx.item_children(def).iter() {
-                        add_child(bfs_queue, child, def);
-                    }
+            while let Some(def) = bfs_queue.pop_front() {
+                for child in tcx.item_children(def).iter() {
+                    add_child(bfs_queue, child, def);
                 }
             }
 

diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs
@@ -1708,9 +1708,10 @@ impl EncodeContext<'a, 'tcx> {
 
     fn encode_crate_deps(&mut self) -> Lazy<[CrateDep]> {
         empty_proc_macro!(self);
-        let crates = self.tcx.crates(());
 
-        let mut deps = crates
+        let deps = self
+            .tcx
+            .crates(())
             .iter()
             .map(|&cnum| {
                 let dep = CrateDep {
@@ -1724,8 +1725,6 @@ impl EncodeContext<'a, 'tcx> {
             })
             .collect::<Vec<_>>();
 
-        deps.sort_by_key(|&(cnum, _)| cnum);
-
         {
             // Sanity-check the crate numbers
             let mut expected_cnum = 1;