Rollup merge of #76724 - ecstatic-morse:dataflow-pass-names, r=lcnr

Allow a unique name to be assigned to dataflow graphviz output

Previously, if the same analysis were invoked multiple times in a single compilation session, the graphviz output for later runs would overwrite that of previous runs. Allow callers to add a unique identifier to each run so this can be avoided.

compiler/rustc_mir/src/transform/check_consts/validation.rs

@@ -59,6 +59,7 @@ impl Qualifs<'mir, 'tcx> {
             MaybeMutBorrowedLocals::mut_borrows_only(tcx, &body, param_env)
                 .unsound_ignore_borrow_on_drop()
                 .into_engine(tcx, &body, def_id.to_def_id())
+                .pass_name("const_qualification")
                 .iterate_to_fixpoint()
                 .into_results_cursor(&body)
         });

compiler/rustc_mir/src/transform/elaborate_drops.rs

@@ -44,6 +44,7 @@ impl<'tcx> MirPass<'tcx> for ElaborateDrops {
             let inits = MaybeInitializedPlaces::new(tcx, body, &env)
                 .into_engine(tcx, body, def_id)
                 .dead_unwinds(&dead_unwinds)
+                .pass_name("elaborate_drops")
                 .iterate_to_fixpoint()
                 .into_results_cursor(body);
 
@@ -51,6 +52,7 @@ impl<'tcx> MirPass<'tcx> for ElaborateDrops {
                 .mark_inactive_variants_as_uninit()
                 .into_engine(tcx, body, def_id)
                 .dead_unwinds(&dead_unwinds)
+                .pass_name("elaborate_drops")
                 .iterate_to_fixpoint()
                 .into_results_cursor(body);
 
@@ -83,6 +85,7 @@ fn find_dead_unwinds<'tcx>(
     let mut dead_unwinds = BitSet::new_empty(body.basic_blocks().len());
     let mut flow_inits = MaybeInitializedPlaces::new(tcx, body, &env)
         .into_engine(tcx, body, def_id)
+        .pass_name("find_dead_unwinds")
         .iterate_to_fixpoint()
         .into_results_cursor(body);
     for (bb, bb_data) in body.basic_blocks().iter_enumerated() {

compiler/rustc_mir/src/transform/generator.rs

@@ -467,8 +467,10 @@ fn locals_live_across_suspend_points(
 
     // Calculate the MIR locals which have been previously
     // borrowed (even if they are still active).
-    let borrowed_locals_results =
-        MaybeBorrowedLocals::all_borrows().into_engine(tcx, body_ref, def_id).iterate_to_fixpoint();
+    let borrowed_locals_results = MaybeBorrowedLocals::all_borrows()
+        .into_engine(tcx, body_ref, def_id)
+        .pass_name("generator")
+        .iterate_to_fixpoint();
 
     let mut borrowed_locals_cursor =
         dataflow::ResultsCursor::new(body_ref, &borrowed_locals_results);
@@ -484,6 +486,7 @@ fn locals_live_across_suspend_points(
     // Calculate the liveness of MIR locals ignoring borrows.
     let mut liveness = MaybeLiveLocals
         .into_engine(tcx, body_ref, def_id)
+        .pass_name("generator")
         .iterate_to_fixpoint()
         .into_results_cursor(body_ref);