Don't create two new closures for each query

- Parameterize DepKindStruct over `'tcx`

    This allows passing in an invariant function pointer in `query_callback`,
    rather than having to try and make it work for any lifetime.

- Add a new `execute_query` function to `QueryDescription` so we can call `tcx.$name` without needing to be in a macro context

Author: jyn514

Diff for: compiler/rustc_middle/src/arena.rs

@@ -100,7 +100,7 @@ macro_rules! arena_types {
             [decode] is_late_bound_map: rustc_data_structures::fx::FxIndexSet<rustc_hir::def_id::LocalDefId>,
             [decode] impl_source: rustc_middle::traits::ImplSource<'tcx, ()>,
 
-            [] dep_kind: rustc_middle::dep_graph::DepKindStruct,
+            [] dep_kind: rustc_middle::dep_graph::DepKindStruct<'tcx>,
         ]);
     )
 }

Diff for: compiler/rustc_middle/src/dep_graph/dep_node.rs

@@ -74,7 +74,7 @@ pub use rustc_query_system::dep_graph::{DepContext, DepNodeParams};
 /// Information is retrieved by indexing the `DEP_KINDS` array using the integer value
 /// of the `DepKind`. Overall, this allows to implement `DepContext` using this manual
 /// jump table instead of large matches.
-pub struct DepKindStruct {
+pub struct DepKindStruct<'tcx> {
     /// Anonymous queries cannot be replayed from one compiler invocation to the next.
     /// When their result is needed, it is recomputed. They are useful for fine-grained
     /// dependency tracking, and caching within one compiler invocation.
@@ -124,10 +124,10 @@ pub struct DepKindStruct {
     /// with kind `MirValidated`, we know that the GUID/fingerprint of the `DepNode`
     /// is actually a `DefPathHash`, and can therefore just look up the corresponding
     /// `DefId` in `tcx.def_path_hash_to_def_id`.
-    pub force_from_dep_node: Option<fn(tcx: TyCtxt<'_>, dep_node: DepNode) -> bool>,
+    pub force_from_dep_node: Option<fn(tcx: TyCtxt<'tcx>, dep_node: DepNode) -> bool>,
 
     /// Invoke a query to put the on-disk cached value in memory.
-    pub try_load_from_on_disk_cache: Option<fn(TyCtxt<'_>, DepNode)>,
+    pub try_load_from_on_disk_cache: Option<fn(TyCtxt<'tcx>, DepNode)>,
 }
 
 impl DepKind {

Diff for: compiler/rustc_middle/src/ty/context.rs

@@ -1089,7 +1089,7 @@ pub struct GlobalCtxt<'tcx> {
 
     pub queries: &'tcx dyn query::QueryEngine<'tcx>,
     pub query_caches: query::QueryCaches<'tcx>,
-    query_kinds: &'tcx [DepKindStruct],
+    query_kinds: &'tcx [DepKindStruct<'tcx>],
 
     // Internal caches for metadata decoding. No need to track deps on this.
     pub ty_rcache: Lock<FxHashMap<ty::CReaderCacheKey, Ty<'tcx>>>,
@@ -1246,7 +1246,7 @@ impl<'tcx> TyCtxt<'tcx> {
         dep_graph: DepGraph,
         on_disk_cache: Option<&'tcx dyn OnDiskCache<'tcx>>,
         queries: &'tcx dyn query::QueryEngine<'tcx>,
-        query_kinds: &'tcx [DepKindStruct],
+        query_kinds: &'tcx [DepKindStruct<'tcx>],
         crate_name: &str,
         output_filenames: OutputFilenames,
     ) -> GlobalCtxt<'tcx> {
@@ -1296,7 +1296,7 @@ impl<'tcx> TyCtxt<'tcx> {
         }
     }
 
-    pub(crate) fn query_kind(self, k: DepKind) -> &'tcx DepKindStruct {
+    pub(crate) fn query_kind(self, k: DepKind) -> &'tcx DepKindStruct<'tcx> {
         &self.query_kinds[k as usize]
     }
 

Diff for: compiler/rustc_query_impl/src/plumbing.rs

@@ -301,11 +301,8 @@ pub(crate) fn create_query_frame<
     QueryStackFrame::new(name, description, span, def_kind, hash)
 }
 
-pub(crate) fn try_load_from_on_disk_cache<'tcx, Q, V>(
-    tcx: TyCtxt<'tcx>,
-    dep_node: DepNode,
-    cache_query_deps: fn(TyCtxt<'tcx>, Q::Key) -> V,
-) where
+fn try_load_from_on_disk_cache<'tcx, Q>(tcx: TyCtxt<'tcx>, dep_node: DepNode)
+where
     Q: QueryDescription<QueryCtxt<'tcx>>,
     Q::Key: DepNodeParams<TyCtxt<'tcx>>,
 {
@@ -315,11 +312,11 @@ pub(crate) fn try_load_from_on_disk_cache<'tcx, Q, V>(
         panic!("Failed to recover key for {:?} with hash {}", dep_node, dep_node.hash)
     });
     if Q::cache_on_disk(tcx, &key) {
-        let _ = cache_query_deps(tcx, key);
+        let _ = Q::execute_query(tcx, key);
     }
 }
 
-pub(crate) fn force_from_dep_node<'tcx, Q>(tcx: TyCtxt<'tcx>, dep_node: DepNode) -> bool
+fn force_from_dep_node<'tcx, Q>(tcx: TyCtxt<'tcx>, dep_node: DepNode) -> bool
 where
     Q: QueryDescription<QueryCtxt<'tcx>>,
     Q::Key: DepNodeParams<TyCtxt<'tcx>>,
@@ -336,13 +333,9 @@ where
 }
 
 pub(crate) fn query_callback<'tcx, Q: QueryConfig>(
-    // NOTE: we can't remove these function pointers, because `recover` is invariant -> `try_load_from_on_disk_cache` takes a concrete lifetime, not a universal lifetime.
-    // Instead, we infer the correct lifetime at the callsite, so we can pass in a HRTB function pointer to the DepKindStruct.
-    try_load_from_on_disk_cache: fn(TyCtxt<'_>, DepNode),
-    force_from_dep_node: fn(TyCtxt<'_>, DepNode) -> bool,
     is_anon: bool,
     is_eval_always: bool,
-) -> DepKindStruct
+) -> DepKindStruct<'tcx>
 where
     Q: QueryDescription<QueryCtxt<'tcx>>,
     Q::Key: DepNodeParams<TyCtxt<'tcx>>,
@@ -363,8 +356,8 @@ where
         is_anon,
         is_eval_always,
         fingerprint_style,
-        force_from_dep_node: Some(force_from_dep_node),
-        try_load_from_on_disk_cache: Some(try_load_from_on_disk_cache),
+        force_from_dep_node: Some(force_from_dep_node::<Q>),
+        try_load_from_on_disk_cache: Some(try_load_from_on_disk_cache::<Q>),
     }
 }
 
@@ -431,6 +424,10 @@ macro_rules! define_queries {
                     try_load_from_disk: Self::TRY_LOAD_FROM_DISK,
                 }
             }
+
+            fn execute_query(tcx: TyCtxt<'tcx>, k: Self::Key) -> Self::Stored {
+                tcx.$name(k)
+            }
         })*
 
         #[allow(nonstandard_style)]
@@ -439,7 +436,7 @@ macro_rules! define_queries {
             use rustc_query_system::dep_graph::FingerprintStyle;
 
             // We use this for most things when incr. comp. is turned off.
-            pub fn Null() -> DepKindStruct {
+            pub fn Null<'tcx>() -> DepKindStruct<'tcx> {
                 DepKindStruct {
                     is_anon: false,
                     is_eval_always: false,
@@ -450,7 +447,7 @@ macro_rules! define_queries {
             }
 
             // We use this for the forever-red node.
-            pub fn Red() -> DepKindStruct {
+            pub fn Red<'tcx>() -> DepKindStruct<'tcx> {
                 DepKindStruct {
                     is_anon: false,
                     is_eval_always: false,
@@ -460,7 +457,7 @@ macro_rules! define_queries {
                 }
             }
 
-            pub fn TraitSelect() -> DepKindStruct {
+            pub fn TraitSelect<'tcx>() -> DepKindStruct<'tcx> {
                 DepKindStruct {
                     is_anon: true,
                     is_eval_always: false,
@@ -470,7 +467,7 @@ macro_rules! define_queries {
                 }
             }
 
-            pub fn CompileCodegenUnit() -> DepKindStruct {
+            pub fn CompileCodegenUnit<'tcx>() -> DepKindStruct<'tcx> {
                 DepKindStruct {
                     is_anon: false,
                     is_eval_always: false,
@@ -480,7 +477,7 @@ macro_rules! define_queries {
                 }
             }
 
-            pub fn CompileMonoItem() -> DepKindStruct {
+            pub fn CompileMonoItem<'tcx>() -> DepKindStruct<'tcx> {
                 DepKindStruct {
                     is_anon: false,
                     is_eval_always: false,
@@ -490,21 +487,15 @@ macro_rules! define_queries {
                 }
             }
 
-            $(pub(crate) fn $name()-> DepKindStruct {
-                let is_anon = is_anon!([$($modifiers)*]);
-                let is_eval_always = is_eval_always!([$($modifiers)*]);
-                type Q<'tcx> = queries::$name<'tcx>;
-
-                $crate::plumbing::query_callback::<Q<'_>>(
-                    |tcx, key| $crate::plumbing::try_load_from_on_disk_cache::<Q<'_>, _>(tcx, key, TyCtxt::$name),
-                    |tcx, key| $crate::plumbing::force_from_dep_node::<Q<'_>>(tcx, key),
-                    is_anon,
-                    is_eval_always
+            $(pub(crate) fn $name<'tcx>()-> DepKindStruct<'tcx> {
+                $crate::plumbing::query_callback::<queries::$name<'tcx>>(
+                    is_anon!([$($modifiers)*]),
+                    is_eval_always!([$($modifiers)*]),
                 )
             })*
         }
 
-        pub fn query_callbacks<'tcx>(arena: &'tcx Arena<'tcx>) -> &'tcx [DepKindStruct] {
+        pub fn query_callbacks<'tcx>(arena: &'tcx Arena<'tcx>) -> &'tcx [DepKindStruct<'tcx>] {
             arena.alloc_from_iter(make_dep_kind_array!(query_callbacks))
         }
     }

Diff for: compiler/rustc_query_system/src/query/config.rs

@@ -73,4 +73,7 @@ pub trait QueryDescription<CTX: QueryContext>: QueryConfig {
     fn make_vtable(tcx: CTX, key: &Self::Key) -> QueryVTable<CTX, Self::Key, Self::Value>;
 
     fn cache_on_disk(tcx: CTX::DepContext, key: &Self::Key) -> bool;
+
+    // Don't use this method to compute query results, instead use the methods on TyCtxt
+    fn execute_query(tcx: CTX::DepContext, k: Self::Key) -> Self::Stored;
 }