Merge QueryEngine into QueryVTable.

`QueryEngine` is a struct with one function pointer per query. This
commit removes it by moving each function pointer into the relevant
query's vtable, which is already a collection of function pointers for
that query. This makes things simpler.

Author: nnethercote

compiler/rustc_middle/src/query/plumbing.rs

@@ -14,7 +14,7 @@ pub use sealed::IntoQueryParam;
 use crate::dep_graph;
 use crate::dep_graph::{DepKind, DepNode, DepNodeIndex, SerializedDepNodeIndex};
 use crate::ich::StableHashingContext;
-use crate::queries::{ExternProviders, PerQueryVTables, Providers, QueryArenas, QueryEngine};
+use crate::queries::{ExternProviders, PerQueryVTables, Providers, QueryArenas};
 use crate::query::on_disk_cache::{CacheEncoder, EncodedDepNodeIndex, OnDiskCache};
 use crate::query::stack::{QueryStackDeferred, QueryStackFrame, QueryStackFrameExtra};
 use crate::query::{QueryCache, QueryInfo, QueryJob};
@@ -145,6 +145,8 @@ pub struct QueryVTable<'tcx, C: QueryCache> {
     ///
     /// Used when reporting query cycle errors and similar problems.
     pub description_fn: fn(TyCtxt<'tcx>, C::Key) -> String,
+
+    pub execute_query_fn: fn(TyCtxt<'tcx>, Span, C::Key, QueryMode) -> Option<C::Value>,
 }
 
 impl<'tcx, C: QueryCache> fmt::Debug for QueryVTable<'tcx, C> {
@@ -203,7 +205,6 @@ impl<'tcx, C: QueryCache> QueryVTable<'tcx, C> {
 }
 
 pub struct QuerySystemFns {
-    pub engine: QueryEngine,
     pub local_providers: Providers,
     pub extern_providers: ExternProviders,
     pub encode_query_results: for<'tcx> fn(
@@ -486,7 +487,7 @@ macro_rules! define_callbacks {
                         (crate::query::inner::query_ensure)
                     )(
                         self.tcx,
-                        self.tcx.query_system.fns.engine.$name,
+                        self.tcx.query_system.query_vtables.$name.execute_query_fn,
                         &self.tcx.query_system.query_vtables.$name.cache,
                         $crate::query::IntoQueryParam::into_query_param(key),
                         false,
@@ -502,7 +503,7 @@ macro_rules! define_callbacks {
                 pub fn $name(self, key: query_helper_param_ty!($($K)*)) {
                     crate::query::inner::query_ensure(
                         self.tcx,
-                        self.tcx.query_system.fns.engine.$name,
+                        self.tcx.query_system.query_vtables.$name.execute_query_fn,
                         &self.tcx.query_system.query_vtables.$name.cache,
                         $crate::query::IntoQueryParam::into_query_param(key),
                         true,
@@ -531,7 +532,7 @@ macro_rules! define_callbacks {
 
                     erase::restore_val::<$V>(inner::query_get_at(
                         self.tcx,
-                        self.tcx.query_system.fns.engine.$name,
+                        self.tcx.query_system.query_vtables.$name.execute_query_fn,
                         &self.tcx.query_system.query_vtables.$name.cache,
                         self.span,
                         $crate::query::IntoQueryParam::into_query_param(key),
@@ -608,17 +609,6 @@ macro_rules! define_callbacks {
         impl Clone for ExternProviders {
             fn clone(&self) -> Self { *self }
         }
-
-        pub struct QueryEngine {
-            $(
-                pub $name: for<'tcx> fn(
-                    TyCtxt<'tcx>,
-                    Span,
-                    $name::Key<'tcx>,
-                    $crate::query::QueryMode,
-                ) -> Option<$crate::query::erase::Erased<$V>>,
-            )*
-        }
     };
 }
 

compiler/rustc_query_impl/src/lib.rs

@@ -10,7 +10,7 @@
 
 use rustc_data_structures::sync::AtomicU64;
 use rustc_middle::dep_graph;
-use rustc_middle::queries::{self, ExternProviders, Providers, QueryEngine};
+use rustc_middle::queries::{self, ExternProviders, Providers};
 use rustc_middle::query::on_disk_cache::{CacheEncoder, EncodedDepNodeIndex, OnDiskCache};
 use rustc_middle::query::plumbing::{QuerySystem, QuerySystemFns, QueryVTable};
 use rustc_middle::query::{AsLocalKey, QueryCache, QueryMode};
@@ -61,10 +61,9 @@ pub fn query_system<'tcx>(
 ) -> QuerySystem<'tcx> {
     QuerySystem {
         arenas: Default::default(),
-        query_vtables: make_query_vtables(),
+        query_vtables: make_query_vtables(incremental),
         on_disk_cache,
         fns: QuerySystemFns {
-            engine: engine(incremental),
             local_providers,
             extern_providers,
             encode_query_results: encode_all_query_results,

compiler/rustc_query_impl/src/plumbing.rs

@@ -549,7 +549,7 @@ macro_rules! define_queries {
                 }
             }
 
-            pub(crate) fn make_query_vtable<'tcx>()
+            pub(crate) fn make_query_vtable<'tcx>(incremental: bool)
                 -> QueryVTable<'tcx, queries::$name::Storage<'tcx>>
             {
                 QueryVTable {
@@ -604,6 +604,11 @@ macro_rules! define_queries {
                     hash_result: hash_result!([$($modifiers)*][queries::$name::Value<'tcx>]),
                     format_value: |value| format!("{:?}", erase::restore_val::<queries::$name::Value<'tcx>>(*value)),
                     description_fn: $crate::queries::_description_fns::$name,
+                    execute_query_fn: if incremental {
+                        query_impl::$name::get_query_incr::__rust_end_short_backtrace
+                    } else {
+                        query_impl::$name::get_query_non_incr::__rust_end_short_backtrace
+                    },
                 }
             }
 
@@ -704,22 +709,10 @@ macro_rules! define_queries {
             }
         })*}
 
-        pub(crate) fn engine(incremental: bool) -> QueryEngine {
-            if incremental {
-                QueryEngine {
-                    $($name: query_impl::$name::get_query_incr::__rust_end_short_backtrace,)*
-                }
-            } else {
-                QueryEngine {
-                    $($name: query_impl::$name::get_query_non_incr::__rust_end_short_backtrace,)*
-                }
-            }
-        }
-
-        pub fn make_query_vtables<'tcx>() -> queries::PerQueryVTables<'tcx> {
+        pub fn make_query_vtables<'tcx>(incremental: bool) -> queries::PerQueryVTables<'tcx> {
             queries::PerQueryVTables {
                 $(
-                    $name: query_impl::$name::make_query_vtable(),
+                    $name: query_impl::$name::make_query_vtable(incremental),
                 )*
             }
         }