Auto merge of #103975 - oli-obk:tracing, r=jackh726

Some tracing and comment cleanups

Pulled out of https://github.com/rust-lang/rust/pull/101900 to see if that is the perf impact

compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs

@@ -146,6 +146,7 @@ impl Qualif for NeedsNonConstDrop {
         qualifs.needs_non_const_drop
     }
 
+    #[instrument(level = "trace", skip(cx), ret)]
     fn in_any_value_of_ty<'tcx>(cx: &ConstCx<'_, 'tcx>, ty: Ty<'tcx>) -> bool {
         // Avoid selecting for simple cases, such as builtin types.
         if ty::util::is_trivially_const_drop(ty) {
@@ -174,6 +175,8 @@ impl Qualif for NeedsNonConstDrop {
             return true;
         };
 
+        trace!(?impl_src);
+
         if !matches!(
             impl_src,
             ImplSource::ConstDestruct(_) | ImplSource::Param(_, ty::BoundConstness::ConstIfConst)

compiler/rustc_hir/src/hir.rs

@@ -388,6 +388,8 @@ impl<'hir> GenericArgs<'hir> {
     }
 
     #[inline]
+    /// This function returns the number of type and const generic params.
+    /// It should only be used for diagnostics.
     pub fn num_generic_params(&self) -> usize {
         self.args.iter().filter(|arg| !matches!(arg, GenericArg::Lifetime(_))).count()
     }

compiler/rustc_hir_typeck/src/callee.rs

@@ -129,6 +129,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         output
     }
 
+    #[instrument(level = "debug", skip(self, call_expr, callee_expr, arg_exprs, autoderef), ret)]
     fn try_overloaded_call_step(
         &self,
         call_expr: &'tcx hir::Expr<'tcx>,
@@ -138,10 +139,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     ) -> Option<CallStep<'tcx>> {
         let adjusted_ty =
             self.structurally_resolved_type(autoderef.span(), autoderef.final_ty(false));
-        debug!(
-            "try_overloaded_call_step(call_expr={:?}, adjusted_ty={:?})",
-            call_expr, adjusted_ty
-        );
 
         // If the callee is a bare function or a closure, then we're all set.
         match *adjusted_ty.kind() {

compiler/rustc_infer/src/infer/canonical/canonicalizer.rs

@@ -495,7 +495,7 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for Canonicalizer<'cx, 'tcx> {
             }
             ty::ConstKind::Bound(debruijn, _) => {
                 if debruijn >= self.binder_index {
-                    bug!("escaping bound type during canonicalization")
+                    bug!("escaping bound const during canonicalization")
                 } else {
                     return ct;
                 }

compiler/rustc_middle/src/ty/instance.rs

@@ -511,12 +511,12 @@ impl<'tcx> Instance<'tcx> {
         Instance::resolve(tcx, ty::ParamEnv::reveal_all(), def_id, substs).unwrap().unwrap()
     }
 
+    #[instrument(level = "debug", skip(tcx), ret)]
     pub fn fn_once_adapter_instance(
         tcx: TyCtxt<'tcx>,
         closure_did: DefId,
         substs: ty::SubstsRef<'tcx>,
     ) -> Option<Instance<'tcx>> {
-        debug!("fn_once_adapter_shim({:?}, {:?})", closure_did, substs);
         let fn_once = tcx.require_lang_item(LangItem::FnOnce, None);
         let call_once = tcx
             .associated_items(fn_once)
@@ -536,7 +536,7 @@ impl<'tcx> Instance<'tcx> {
         assert_eq!(sig.inputs().len(), 1);
         let substs = tcx.mk_substs_trait(self_ty, &[sig.inputs()[0].into()]);
 
-        debug!("fn_once_adapter_shim: self_ty={:?} sig={:?}", self_ty, sig);
+        debug!(?self_ty, ?sig);
         Some(Instance { def, substs })
     }
 

compiler/rustc_mir_dataflow/src/elaborate_drops.rs

@@ -407,9 +407,8 @@ where
         self.drop_ladder(fields, succ, unwind).0
     }
 
+    #[instrument(level = "debug", ret)]
     fn open_drop_for_box(&mut self, adt: ty::AdtDef<'tcx>, substs: SubstsRef<'tcx>) -> BasicBlock {
-        debug!("open_drop_for_box({:?}, {:?}, {:?})", self, adt, substs);
-
         // drop glue is sent straight to codegen
         // box cannot be directly dereferenced
         let unique_ty = adt.non_enum_variant().fields[0].ty(self.tcx(), substs);
@@ -431,8 +430,8 @@ where
         self.drop_subpath(interior, interior_path, succ, unwind_succ)
     }
 
+    #[instrument(level = "debug", ret)]
     fn open_drop_for_adt(&mut self, adt: ty::AdtDef<'tcx>, substs: SubstsRef<'tcx>) -> BasicBlock {
-        debug!("open_drop_for_adt({:?}, {:?}, {:?})", self, adt, substs);
         if adt.variants().is_empty() {
             return self.elaborator.patch().new_block(BasicBlockData {
                 statements: vec![],

compiler/rustc_mir_transform/src/shim.rs

@@ -569,17 +569,13 @@ impl<'tcx> CloneShimBuilder<'tcx> {
 
 /// Builds a "call" shim for `instance`. The shim calls the function specified by `call_kind`,
 /// first adjusting its first argument according to `rcvr_adjustment`.
+#[instrument(level = "debug", skip(tcx), ret)]
 fn build_call_shim<'tcx>(
     tcx: TyCtxt<'tcx>,
     instance: ty::InstanceDef<'tcx>,
     rcvr_adjustment: Option<Adjustment>,
     call_kind: CallKind<'tcx>,
 ) -> Body<'tcx> {
-    debug!(
-        "build_call_shim(instance={:?}, rcvr_adjustment={:?}, call_kind={:?})",
-        instance, rcvr_adjustment, call_kind
-    );
-
     // `FnPtrShim` contains the fn pointer type that a call shim is being built for - this is used
     // to substitute into the signature of the shim. It is not necessary for users of this
     // MIR body to perform further substitutions (see `InstanceDef::has_polymorphic_mir_body`).
@@ -641,7 +637,7 @@ fn build_call_shim<'tcx>(
 
     let span = tcx.def_span(def_id);
 
-    debug!("build_call_shim: sig={:?}", sig);
+    debug!(?sig);
 
     let mut local_decls = local_decls_for_sig(&sig, span);
     let source_info = SourceInfo::outermost(span);

compiler/rustc_trait_selection/src/infer.rs

@@ -93,6 +93,7 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
 
     /// Normalizes associated types in `value`, potentially returning
     /// new obligations that must further be processed.
+    #[instrument(level = "debug", skip(self, cause, param_env), ret)]
     fn partially_normalize_associated_types_in<T>(
         &self,
         cause: ObligationCause<'tcx>,
@@ -102,17 +103,13 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
     where
         T: TypeFoldable<'tcx>,
     {
-        debug!("partially_normalize_associated_types_in(value={:?})", value);
         let mut selcx = traits::SelectionContext::new(self);
         let traits::Normalized { value, obligations } =
             traits::normalize(&mut selcx, param_env, cause, value);
-        debug!(
-            "partially_normalize_associated_types_in: result={:?} predicates={:?}",
-            value, obligations
-        );
         InferOk { value, obligations }
     }
 
+    #[instrument(level = "debug", skip(self), ret)]
     fn type_implements_trait(
         &self,
         trait_def_id: DefId,
@@ -120,11 +117,6 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
         params: SubstsRef<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
     ) -> traits::EvaluationResult {
-        debug!(
-            "type_implements_trait: trait_def_id={:?}, type={:?}, params={:?}, param_env={:?}",
-            trait_def_id, ty, params, param_env
-        );
-
         let trait_ref =
             ty::TraitRef { def_id: trait_def_id, substs: self.tcx.mk_substs_trait(ty, params) };
 

compiler/rustc_trait_selection/src/traits/mod.rs

@@ -117,14 +117,12 @@ pub enum TraitQueryMode {
 }
 
 /// Creates predicate obligations from the generic bounds.
+#[instrument(level = "debug", skip(cause, param_env))]
 pub fn predicates_for_generics<'tcx>(
     cause: impl Fn(usize, Span) -> ObligationCause<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     generic_bounds: ty::InstantiatedPredicates<'tcx>,
 ) -> impl Iterator<Item = PredicateObligation<'tcx>> {
-    let generic_bounds = generic_bounds;
-    debug!("predicates_for_generics(generic_bounds={:?})", generic_bounds);
-
     std::iter::zip(generic_bounds.predicates, generic_bounds.spans).enumerate().map(
         move |(idx, (predicate, span))| Obligation {
             cause: cause(idx, span),
@@ -140,6 +138,7 @@ pub fn predicates_for_generics<'tcx>(
 /// `bound` or is not known to meet bound (note that this is
 /// conservative towards *no impl*, which is the opposite of the
 /// `evaluate` methods).
+#[instrument(level = "debug", skip(infcx, param_env, span), ret)]
 pub fn type_known_to_meet_bound_modulo_regions<'tcx>(
     infcx: &InferCtxt<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
@@ -147,12 +146,6 @@ pub fn type_known_to_meet_bound_modulo_regions<'tcx>(
     def_id: DefId,
     span: Span,
 ) -> bool {
-    debug!(
-        "type_known_to_meet_bound_modulo_regions(ty={:?}, bound={:?})",
-        ty,
-        infcx.tcx.def_path_str(def_id)
-    );
-
     let trait_ref =
         ty::Binder::dummy(ty::TraitRef { def_id, substs: infcx.tcx.mk_substs_trait(ty, &[]) });
     let obligation = Obligation {
@@ -163,12 +156,7 @@ pub fn type_known_to_meet_bound_modulo_regions<'tcx>(
     };
 
     let result = infcx.predicate_must_hold_modulo_regions(&obligation);
-    debug!(
-        "type_known_to_meet_ty={:?} bound={} => {:?}",
-        ty,
-        infcx.tcx.def_path_str(def_id),
-        result
-    );
+    debug!(?result);
 
     if result && ty.has_non_region_infer() {
         // Because of inference "guessing", selection can sometimes claim
@@ -190,21 +178,9 @@ pub fn type_known_to_meet_bound_modulo_regions<'tcx>(
         // *definitively* show that it implements `Copy`. Otherwise,
         // assume it is move; linear is always ok.
         match &errors[..] {
-            [] => {
-                debug!(
-                    "type_known_to_meet_bound_modulo_regions: ty={:?} bound={} success",
-                    ty,
-                    infcx.tcx.def_path_str(def_id)
-                );
-                true
-            }
+            [] => true,
             errors => {
-                debug!(
-                    ?ty,
-                    bound = %infcx.tcx.def_path_str(def_id),
-                    ?errors,
-                    "type_known_to_meet_bound_modulo_regions"
-                );
+                debug!(?errors);
                 false
             }
         }

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -1132,12 +1132,13 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
     /// filter_impls filters constant trait obligations and candidates that have a positive impl
     /// for a negative goal and a negative impl for a positive goal
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self, candidates))]
     fn filter_impls(
         &mut self,
         candidates: Vec<SelectionCandidate<'tcx>>,
         obligation: &TraitObligation<'tcx>,
     ) -> Vec<SelectionCandidate<'tcx>> {
+        trace!("{candidates:#?}");
         let tcx = self.tcx();
         let mut result = Vec::with_capacity(candidates.len());
 
@@ -1177,6 +1178,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             }
         }
 
+        trace!("{result:#?}");
         result
     }