Use &C::Key less in queries.

Currently we use a mix of `C::Key` and `&C::Key` parameters. The former
is more common and a bit nicer, so convert some of the latter. This
results in less converting between the two types, and fewer sigils.

Author: nnethercote

compiler/rustc_macros/src/query.rs

@@ -355,11 +355,10 @@ fn make_helpers_for_query(query: &Query, streams: &mut HelperTokenStreams) {
 
     // Generate a function to check whether we should cache the query to disk, for some key.
     if let Some(CacheOnDiskIf { block, .. }) = modifiers.cache_on_disk_if.as_ref() {
-        // `disallowed_pass_by_ref` is needed because some keys are `rustc_pass_by_value`.
         streams.cache_on_disk_if_fns_stream.extend(quote! {
-            #[allow(unused_variables, rustc::disallowed_pass_by_ref)]
+            #[allow(unused_variables)]
             #[inline]
-            pub fn #erased_name<'tcx>(tcx: TyCtxt<'tcx>, #key_pat: &#key_ty) -> bool
+            pub fn #erased_name<'tcx>(tcx: TyCtxt<'tcx>, #key_pat: #key_ty) -> bool
             #block
         });
     }

compiler/rustc_middle/src/queries.rs

@@ -2391,7 +2391,7 @@ rustc_queries! {
     ///   sets of different crates do not intersect.
     query exported_non_generic_symbols(cnum: CrateNum) -> &'tcx [(ExportedSymbol<'tcx>, SymbolExportInfo)] {
         desc { "collecting exported non-generic symbols for crate `{}`", cnum}
-        cache_on_disk_if { *cnum == LOCAL_CRATE }
+        cache_on_disk_if { cnum == LOCAL_CRATE }
         separate_provide_extern
     }
 
@@ -2404,7 +2404,7 @@ rustc_queries! {
     ///   sets of different crates do not intersect.
     query exported_generic_symbols(cnum: CrateNum) -> &'tcx [(ExportedSymbol<'tcx>, SymbolExportInfo)] {
         desc { "collecting exported generic symbols for crate `{}`", cnum}
-        cache_on_disk_if { *cnum == LOCAL_CRATE }
+        cache_on_disk_if { cnum == LOCAL_CRATE }
         separate_provide_extern
     }
 
@@ -2771,7 +2771,7 @@ rustc_queries! {
     query externally_implementable_items(cnum: CrateNum) -> &'tcx FxIndexMap<DefId, (EiiDecl, FxIndexMap<DefId, EiiImpl>)> {
         arena_cache
         desc { "looking up the externally implementable items of a crate" }
-        cache_on_disk_if { *cnum == LOCAL_CRATE }
+        cache_on_disk_if { cnum == LOCAL_CRATE }
         separate_provide_extern
     }
 

compiler/rustc_middle/src/query/inner.rs

@@ -15,11 +15,11 @@ use crate::ty::TyCtxt;
 ///
 /// (Also performs some associated bookkeeping, if a value was found.)
 #[inline(always)]
-fn try_get_cached<'tcx, C>(tcx: TyCtxt<'tcx>, cache: &C, key: &C::Key) -> Option<C::Value>
+fn try_get_cached<'tcx, C>(tcx: TyCtxt<'tcx>, cache: &C, key: C::Key) -> Option<C::Value>
 where
     C: QueryCache,
 {
-    match cache.lookup(key) {
+    match cache.lookup(&key) {
         Some((value, index)) => {
             tcx.prof.query_cache_hit(index.into());
             tcx.dep_graph.read_index(index);
@@ -41,7 +41,7 @@ pub(crate) fn query_get_at<'tcx, C>(
 where
     C: QueryCache,
 {
-    match try_get_cached(tcx, &query.cache, &key) {
+    match try_get_cached(tcx, &query.cache, key) {
         Some(value) => value,
         None => (query.execute_query_fn)(tcx, span, key, QueryMode::Get).unwrap(),
     }
@@ -58,7 +58,7 @@ pub(crate) fn query_ensure_ok_or_done<'tcx, C>(
 ) where
     C: QueryCache,
 {
-    match try_get_cached(tcx, &query.cache, &key) {
+    match try_get_cached(tcx, &query.cache, key) {
         Some(_value) => {}
         None => {
             (query.execute_query_fn)(tcx, DUMMY_SP, key, QueryMode::Ensure { ensure_mode });
@@ -78,7 +78,7 @@ where
     C: QueryCache<Value = Erased<Result<T, ErrorGuaranteed>>>,
     Result<T, ErrorGuaranteed>: Erasable,
 {
-    match try_get_cached(tcx, &query.cache, &key) {
+    match try_get_cached(tcx, &query.cache, key) {
         Some(value) => erase::restore_val(value).map(drop),
         None => (query.execute_query_fn)(
             tcx,
@@ -112,7 +112,7 @@ pub(crate) fn query_feed<'tcx, C>(
     let format_value = query_vtable.format_value;
 
     // Check whether the in-memory cache already has a value for this key.
-    match try_get_cached(tcx, &query_vtable.cache, &key) {
+    match try_get_cached(tcx, &query_vtable.cache, key) {
         Some(old) => {
             // The query already has a cached value for this key.
             // That's OK if both values are the same, i.e. they have the same hash,

compiler/rustc_middle/src/query/plumbing.rs

@@ -121,17 +121,17 @@ pub struct QueryVTable<'tcx, C: QueryCache> {
     /// This should be the only code that calls the provider function.
     pub invoke_provider_fn: fn(tcx: TyCtxt<'tcx>, key: C::Key) -> C::Value,
 
-    pub will_cache_on_disk_for_key_fn: fn(tcx: TyCtxt<'tcx>, key: &C::Key) -> bool,
+    pub will_cache_on_disk_for_key_fn: fn(tcx: TyCtxt<'tcx>, key: C::Key) -> bool,
 
     pub try_load_from_disk_fn: fn(
         tcx: TyCtxt<'tcx>,
-        key: &C::Key,
+        key: C::Key,
         prev_index: SerializedDepNodeIndex,
         index: DepNodeIndex,
     ) -> Option<C::Value>,
 
     pub is_loadable_from_disk_fn:
-        fn(tcx: TyCtxt<'tcx>, key: &C::Key, index: SerializedDepNodeIndex) -> bool,
+        fn(tcx: TyCtxt<'tcx>, key: C::Key, index: SerializedDepNodeIndex) -> bool,
 
     /// Function pointer that hashes this query's result values.
     ///

compiler/rustc_query_impl/src/execution.rs

@@ -22,8 +22,8 @@ use crate::job::{QueryJobInfo, QueryJobMap, find_cycle_in_stack, report_cycle};
 use crate::plumbing::{current_query_job, next_job_id, start_query};
 
 #[inline]
-fn equivalent_key<K: Eq, V>(k: &K) -> impl Fn(&(K, V)) -> bool + '_ {
-    move |x| x.0 == *k
+fn equivalent_key<K: Eq, V>(k: K) -> impl Fn(&(K, V)) -> bool {
+    move |x| x.0 == k
 }
 
 /// Obtains the enclosed [`QueryJob`], or panics if this query evaluation
@@ -173,7 +173,7 @@ where
             // since unwinding also wants to look at this map, this can also prevent a double
             // panic.
             let mut shard = state.active.lock_shard_by_hash(key_hash);
-            match shard.find_entry(key_hash, equivalent_key(&key)) {
+            match shard.find_entry(key_hash, equivalent_key(key)) {
                 Err(_) => None,
                 Ok(occupied) => Some(occupied.remove().0.1),
             }
@@ -195,7 +195,7 @@ where
         let Self { state, key, key_hash } = *self;
         let job = {
             let mut shard = state.active.lock_shard_by_hash(key_hash);
-            match shard.find_entry(key_hash, equivalent_key(&key)) {
+            match shard.find_entry(key_hash, equivalent_key(key)) {
                 Err(_) => panic!(),
                 Ok(occupied) => {
                     let ((key, value), vacant) = occupied.remove();
@@ -254,7 +254,7 @@ fn wait_for_query<'tcx, C: QueryCache>(
                     // poisoned due to a panic instead.
                     let key_hash = sharded::make_hash(&key);
                     let shard = query.state.active.lock_shard_by_hash(key_hash);
-                    match shard.find(key_hash, equivalent_key(&key)) {
+                    match shard.find(key_hash, equivalent_key(key)) {
                         // The query we waited on panicked. Continue unwinding here.
                         Some((_, ActiveKeyStatus::Poisoned)) => FatalError.raise(),
                         _ => panic!(
@@ -303,7 +303,7 @@ fn try_execute_query<'tcx, C: QueryCache, const INCR: bool>(
 
     let current_job_id = current_query_job();
 
-    match state_lock.entry(key_hash, equivalent_key(&key), |(k, _)| sharded::make_hash(k)) {
+    match state_lock.entry(key_hash, equivalent_key(key), |(k, _)| sharded::make_hash(k)) {
         Entry::Vacant(entry) => {
             // Nothing has computed or is computing the query, so we start a new job and insert it in the
             // state map.
@@ -459,7 +459,7 @@ fn execute_job_incr<'tcx, C: QueryCache>(
                 tcx,
                 dep_graph_data,
                 query,
-                &key,
+                key,
                 dep_node,
                 prev_index,
                 dep_node_index,
@@ -507,7 +507,7 @@ fn load_from_disk_or_invoke_provider_green<'tcx, C: QueryCache>(
     tcx: TyCtxt<'tcx>,
     dep_graph_data: &DepGraphData,
     query: &'tcx QueryVTable<'tcx, C>,
-    key: &C::Key,
+    key: C::Key,
     dep_node: &DepNode,
     prev_index: SerializedDepNodeIndex,
     dep_node_index: DepNodeIndex,
@@ -570,7 +570,7 @@ fn load_from_disk_or_invoke_provider_green<'tcx, C: QueryCache>(
 
     // The dep-graph for this computation is already in-place.
     // Call the query provider.
-    let value = tcx.dep_graph.with_ignore(|| (query.invoke_provider_fn)(tcx, *key));
+    let value = tcx.dep_graph.with_ignore(|| (query.invoke_provider_fn)(tcx, key));
 
     prof_timer.finish_with_query_invocation_id(dep_node_index.into());
 
@@ -615,7 +615,7 @@ struct EnsureCanSkip {
 fn check_if_ensure_can_skip_execution<'tcx, C: QueryCache>(
     query: &'tcx QueryVTable<'tcx, C>,
     tcx: TyCtxt<'tcx>,
-    key: &C::Key,
+    key: C::Key,
     ensure_mode: EnsureMode,
 ) -> EnsureCanSkip {
     // Queries with `eval_always` should never skip execution.
@@ -626,7 +626,7 @@ fn check_if_ensure_can_skip_execution<'tcx, C: QueryCache>(
     // Ensuring an anonymous query makes no sense
     assert!(!query.anon);
 
-    let dep_node = DepNode::construct(tcx, query.dep_kind, key);
+    let dep_node = DepNode::construct(tcx, query.dep_kind, &key);
 
     let dep_graph = &tcx.dep_graph;
     let serialized_dep_node_index = match dep_graph.try_mark_green(tcx, &dep_node) {
@@ -695,7 +695,7 @@ pub(super) fn execute_query_incr_inner<'tcx, C: QueryCache>(
     let dep_node: Option<DepNode> = match mode {
         QueryMode::Ensure { ensure_mode } => {
             let EnsureCanSkip { skip_execution, dep_node } =
-                check_if_ensure_can_skip_execution(query, tcx, &key, ensure_mode);
+                check_if_ensure_can_skip_execution(query, tcx, key, ensure_mode);
             if skip_execution {
                 // Return early to skip execution.
                 return None;

compiler/rustc_query_impl/src/plumbing.rs

@@ -163,7 +163,7 @@ pub(crate) fn encode_query_results<'a, 'tcx, C, V>(
 
     assert!(all_inactive(&query.state));
     query.cache.for_each(&mut |key, value, dep_node| {
-        if (query.will_cache_on_disk_for_key_fn)(tcx, key) {
+        if (query.will_cache_on_disk_for_key_fn)(tcx, *key) {
             let dep_node = SerializedDepNodeIndex::new(dep_node.index());
 
             // Record position of the cache entry.
@@ -219,7 +219,7 @@ pub(crate) fn promote_from_disk_inner<'tcx, Q: GetQueryVTable<'tcx>>(
 
     // If the recovered key isn't eligible for cache-on-disk, then there's no
     // value on disk to promote.
-    if !(query.will_cache_on_disk_for_key_fn)(tcx, &key) {
+    if !(query.will_cache_on_disk_for_key_fn)(tcx, key) {
         return;
     }