Split mir_promoted query again.

Author: cjgillot

compiler/rustc_borrowck/src/root_cx.rs

@@ -268,7 +268,7 @@ impl<'tcx> BorrowCheckRootCtxt<'tcx> {
         for def_id in all_bodies {
             // The list of promoted from a given body is a flat list,
             // in topological order from innermost to outermost.
-            let (_, promoted) = self.tcx.mir_promoted(def_id);
+            let promoted = self.tcx.promoted_mir(def_id);
             for &promoted_def_id in promoted {
                 let result = borrowck_collect_region_constraints(self, promoted_def_id);
                 self.collect_region_constraints_results.insert(promoted_def_id, result);

compiler/rustc_interface/src/passes.rs

@@ -1146,7 +1146,7 @@ fn run_required_analyses(tcx: TyCtxt<'_>) {
                 tcx.ensure_ok().mir_drops_elaborated_and_const_checked(def_id);
 
                 if tcx.trivial_const(def_id).is_none() {
-                    for &promoted in tcx.mir_promoted(def_id).1 {
+                    for &promoted in tcx.promoted_mir(def_id) {
                         tcx.ensure_ok().mir_drops_elaborated_and_const_checked(promoted);
                     }
                 }

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -2313,7 +2313,7 @@ fn prefetch_mir(tcx: TyCtxt<'_>) {
             tcx.ensure_done().optimized_mir(def_id);
         }
         if encode_opt || encode_const {
-            tcx.ensure_done().mir_promoted(def_id);
+            tcx.ensure_done().promoted_mir(def_id);
         }
     })
 }

compiler/rustc_middle/src/mir/pretty.rs

@@ -329,7 +329,7 @@ pub fn write_mir_pretty<'tcx>(
             writer.write_mir_fn(body, w)?;
 
             if let Some(def_id) = def_id.as_local() {
-                for body in tcx.mir_promoted(def_id).1 {
+                for body in tcx.promoted_mir(def_id) {
                     writeln!(w)?;
                     let body = tcx.mir_for_ctfe(body.to_def_id());
                     writer.write_mir_fn(body, w)?;

compiler/rustc_middle/src/queries.rs

@@ -678,11 +678,8 @@ rustc_queries! {
         separate_provide_extern
     }
 
-    /// The `DefId` is the `DefId` of the containing MIR body. Promoteds do not have their own
-    /// `DefId`. This function returns all promoteds in the specified body. The body references
-    /// promoteds by the `DefId` and the `mir::Promoted` index. This is necessary, because
-    /// after inlining a body may refer to promoteds from other bodies. In that case you still
-    /// need to use the `DefId` of the original body.
+    /// The `DefId` is the `DefId` of the containing MIR body.
+    /// This query creates new `DefId`s for promoted-out constants.
     query mir_promoted(key: LocalDefId) -> (
         &'tcx Steal<mir::Body<'tcx>>,
         &'tcx IndexVec<mir::Promoted, LocalDefId>,
@@ -692,6 +689,12 @@ rustc_queries! {
         desc { "promoting constants in MIR for `{}`", tcx.def_path_str(key) }
     }
 
+    query promoted_mir(key: LocalDefId) -> &'tcx IndexVec<mir::Promoted, LocalDefId> {
+        feedable
+        cache_on_disk
+        desc { "promoted constants in MIR for `{}`", tcx.def_path_str(key) }
+    }
+
     query closure_typeinfo(key: LocalDefId) -> ty::ClosureTypeInfo<'tcx> {
         desc {
             "finding symbols for captures of closure `{}`",

compiler/rustc_mir_transform/src/lib.rs

@@ -229,6 +229,7 @@ pub fn provide(providers: &mut Providers) {
         is_mir_available,
         mir_callgraph_cyclic: inline::cycle::mir_callgraph_cyclic,
         mir_inliner_callees: inline::cycle::mir_inliner_callees,
+        promoted_mir,
         deduced_param_attrs: deduce_param_attrs::deduced_param_attrs,
         coroutine_by_move_body_def_id: coroutine::coroutine_by_move_body_def_id,
         trivial_const: trivial_const::trivial_const_provider,
@@ -353,7 +354,7 @@ fn mir_keys(tcx: TyCtxt<'_>, (): ()) -> FxIndexSet<LocalDefId> {
     let mut promoted = Vec::new();
     for &item in set.iter() {
         if tcx.trivial_const(item).is_none() {
-            let (_, promoted_in_item) = tcx.mir_promoted(item);
+            let promoted_in_item = tcx.promoted_mir(item);
             promoted.extend_from_slice(&promoted_in_item.raw);
         }
     }
@@ -848,3 +849,9 @@ fn inner_optimized_mir(tcx: TyCtxt<'_>, did: LocalDefId) -> Body<'_> {
 
     body
 }
+
+/// Fetch all the promoteds of an item and prepare their MIR bodies to be ready for
+/// constant evaluation once all generic parameters become known.
+fn promoted_mir(tcx: TyCtxt<'_>, def: LocalDefId) -> &IndexVec<Promoted, LocalDefId> {
+    tcx.mir_promoted(def).1
+}