Rename query_dispatcher and reduce its use.

It's now `query_vtable` because its return type changed. And thanks to
the previous commit it can be manually inlined in several places. (The
only remaining calls to it are in `make_dep_kind_vtable_for_query`,
which are more challenging to remove.)

Author: nnethercote

compiler/rustc_query_impl/src/dep_kind_vtables.rs

@@ -140,10 +140,10 @@ where
         is_eval_always,
         key_fingerprint_style,
         force_from_dep_node: Some(|tcx, dep_node, _| {
-            force_from_dep_node_inner(Q::query_dispatcher(tcx), tcx, dep_node)
+            force_from_dep_node_inner(Q::query_vtable(tcx), tcx, dep_node)
         }),
         try_load_from_on_disk_cache: Some(|tcx, dep_node| {
-            try_load_from_on_disk_cache_inner(Q::query_dispatcher(tcx), tcx, dep_node)
+            try_load_from_on_disk_cache_inner(Q::query_vtable(tcx), tcx, dep_node)
         }),
         name: Q::NAME,
     }

compiler/rustc_query_impl/src/lib.rs

@@ -37,10 +37,9 @@ mod job;
 mod profiling_support;
 mod values;
 
-/// Provides access to vtable-like operations for a query
-/// (by creating a [`SemiDynamicQueryDispatcher`]),
-/// but also keeps track of the "unerased" value type of the query
-/// (i.e. the actual result type in the query declaration).
+/// Provides access to vtable-like operations for a query (by creating a
+/// `QueryVTable`), but also keeps track of the "unerased" value type of the
+/// query (i.e. the actual result type in the query declaration).
 ///
 /// This trait allows some per-query code to be defined in generic functions
 /// with a trait bound, instead of having to be defined inline within a macro
@@ -53,7 +52,7 @@ trait QueryDispatcherUnerased<'tcx, C: QueryCache> {
 
     const NAME: &'static &'static str;
 
-    fn query_dispatcher(tcx: TyCtxt<'tcx>) -> &'tcx QueryVTable<'tcx, C>;
+    fn query_vtable(tcx: TyCtxt<'tcx>) -> &'tcx QueryVTable<'tcx, C>;
 
     fn restore_val(value: C::Value) -> Self::UnerasedValue;
 }

compiler/rustc_query_impl/src/plumbing.rs

@@ -503,7 +503,7 @@ macro_rules! define_queries {
                     #[cfg(debug_assertions)]
                     let _guard = tracing::span!(tracing::Level::TRACE, stringify!($name), ?key).entered();
                     execution::get_query_incr(
-                        QueryType::query_dispatcher(tcx),
+                        &tcx.query_system.query_vtables.$name,
                         tcx,
                         span,
                         key,
@@ -523,7 +523,7 @@ macro_rules! define_queries {
                     __mode: QueryMode,
                 ) -> Option<Erased<queries::$name::Value<'tcx>>> {
                     Some(execution::get_query_non_incr(
-                        QueryType::query_dispatcher(tcx),
+                        &tcx.query_system.query_vtables.$name,
                         tcx,
                         span,
                         key,
@@ -632,7 +632,7 @@ macro_rules! define_queries {
                 const NAME: &'static &'static str = &stringify!($name);
 
                 #[inline(always)]
-                fn query_dispatcher(tcx: TyCtxt<'tcx>)
+                fn query_vtable(tcx: TyCtxt<'tcx>)
                     -> &'tcx QueryVTable<'tcx, queries::$name::Storage<'tcx>>
                 {
                     &tcx.query_system.query_vtables.$name
@@ -701,7 +701,7 @@ macro_rules! define_queries {
                         query_impl::$name::QueryType<'tcx>,
                         _
                     > (
-                        query_impl::$name::QueryType::query_dispatcher(tcx),
+                        &tcx.query_system.query_vtables.$name,
                         tcx,
                         encoder,
                         query_result_index,
@@ -711,7 +711,7 @@ macro_rules! define_queries {
 
             pub(crate) fn query_key_hash_verify<'tcx>(tcx: TyCtxt<'tcx>) {
                 $crate::plumbing::query_key_hash_verify(
-                    query_impl::$name::QueryType::query_dispatcher(tcx),
+                    &tcx.query_system.query_vtables.$name,
                     tcx,
                 )
             }