Add some logging to query cycles

```
rustc_query_impl::execution::try_execute_query query="hir_crate_items"
  ...
  rustc_query_impl::execution::try_execute_query query="lower_delayed_owner"
    ...
    rustc_query_impl::execution::try_execute_query query="asyncness"
    rustc_query_impl::execution::try_execute_query query="codegen_fn_attrs"
      rustc_query_impl::execution::try_execute_query query="hir_crate_items"
        0ms INFO rustc_query_impl::execution hit a query cycle evaluating hir_crate_items!
        rustc_middle::queries::default_span self=hir_crate_items(())
        rustc_middle::queries::default_span self=lower_delayed_owner(DefId(0:14 ~ bad_resolve[0a7b]::{impl#1}::bar))
          rustc_query_impl::execution::try_execute_query query="def_span"
            rustc_query_impl::execution::try_execute_query query="local_def_id_to_hir_id"
              rustc_query_impl::execution::try_execute_query query="lower_delayed_owner"
                0ms INFO rustc_query_impl::execution hit a query cycle evaluating lower_delayed_owner!
                rustc_middle::queries::default_span self=lower_delayed_owner(DefId(0:14 ~ bad_resolve[0a7b]::{impl#1}::bar))
                  rustc_query_impl::execution::try_execute_query query="def_span"
                    0ms INFO rustc_query_impl::execution hit a query cycle evaluating def_span!
                    rustc_middle::queries::default_span self=def_span(DefId(0:14 ~ bad_resolve[0a7b]::{impl#1}::bar))
                    rustc_query_impl::execution::try_execute_query query="def_span"
                      rustc_query_impl::execution::try_execute_query query="local_def_id_to_hir_id"
                      rustc_query_impl::execution::try_execute_query query="opt_hir_owner_nodes"
                    rustc_middle::queries::default_span self=local_def_id_to_hir_id(DefId(0:14 ~ bad_resolve[0a7b]::{impl#1}::bar))
                      rustc_query_impl::execution::try_execute_query query="def_span"
```

Author: jyn514

compiler/rustc_middle/src/query/plumbing.rs

@@ -454,6 +454,7 @@ macro_rules! define_callbacks {
             }
 
             /// Returns the default span for this query if `span` is a dummy span.
+            #[tracing::instrument(level = "debug", skip(tcx, span))]
             pub fn default_span(&self, tcx: TyCtxt<'tcx>, span: Span) -> Span {
                 if !span.is_dummy() {
                     return span

compiler/rustc_query_impl/src/execution.rs

@@ -223,6 +223,8 @@ fn find_and_handle_cycle<'tcx, C: QueryCache>(
     try_execute: QueryJobId,
     span: Span,
 ) -> (C::Value, Option<DepNodeIndex>) {
+    tracing::info!("hit a query cycle evaluating {}!", query.name);
+
     // Ensure there were no errors collecting all active jobs.
     // We need the complete map to ensure we find a cycle to break.
     let job_map = collect_active_query_jobs(tcx, CollectActiveJobsKind::FullNoContention);
@@ -278,6 +280,7 @@ fn wait_for_query<'tcx, C: QueryCache>(
 
 /// Shared main part of both [`execute_query_incr_inner`] and [`execute_query_non_incr_inner`].
 #[inline(never)]
+#[tracing::instrument(level = "debug", skip_all, fields(query = query.name, key))]
 fn try_execute_query<'tcx, C: QueryCache, const INCR: bool>(
     query: &'tcx QueryVTable<'tcx, C>,
     tcx: TyCtxt<'tcx>,