Rollup merge of rust-lang#153161 - nnethercote:rejig-rustc_with_all_queries, r=Zalathar

JonathanBrouwer · web-flow · commit 34fd06ef6656 · 2026-03-02T20:10:35.000+01:00
Rejig `rustc_with_all_queries!` There are three things relating to `rustc_with_all_queries!` that have been bugging me. - `rustc_with_all_queries!`'s ability to receive `extra_fake_queries` lines like `[] fn Null(()) -> (),` where the only real thing is the `Null`, and everything is just pretending to be a normal query, ugh. - `make_dep_kind_array!`: a macro produced by one macro (`define_dep_nodes!`) and used by another macro (`define_queries!`) in another crate, ugh. - The `_dep_kind_vtable_ctors` module, which is a special module with no actual code that serves just a way of collecting vtable constructors from two different places so they can be referred to by `make_dep_kind_array!`, ugh. By making some adjustments to how `rustc_with_all_queries!` works, all three of these things are eliminated. r? @Zalathar
diff --git a/compiler/rustc_macros/src/query.rs b/compiler/rustc_macros/src/query.rs
@@ -10,6 +10,7 @@ use syn::{
 };
 
 mod kw {
+    syn::custom_keyword!(non_query);
     syn::custom_keyword!(query);
 }
 
@@ -54,12 +55,37 @@ struct Query {
     modifiers: QueryModifiers,
 }
 
-impl Parse for Query {
+/// Declaration of a non-query dep kind.
+/// ```ignore (illustrative)
+/// /// Doc comment for `MyNonQuery`.
+/// //  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  doc_comments
+/// non_query MyNonQuery
+/// //        ^^^^^^^^^^               name
+/// ```
+struct NonQuery {
+    doc_comments: Vec<Attribute>,
+    name: Ident,
+}
+
+enum QueryEntry {
+    Query(Query),
+    NonQuery(NonQuery),
+}
+
+impl Parse for QueryEntry {
     fn parse(input: ParseStream<'_>) -> Result<Self> {
         let mut doc_comments = check_attributes(input.call(Attribute::parse_outer)?)?;
 
+        // Try the non-query case first.
+        if input.parse::<kw::non_query>().is_ok() {
+            let name: Ident = input.parse()?;
+            return Ok(QueryEntry::NonQuery(NonQuery { doc_comments, name }));
+        }
+
         // Parse the query declaration. Like `query type_of(key: DefId) -> Ty<'tcx>`
-        input.parse::<kw::query>()?;
+        if input.parse::<kw::query>().is_err() {
+            return Err(input.error("expected `query` or `non_query`"));
+        }
         let name: Ident = input.parse()?;
 
         // `(key: DefId)`
@@ -84,7 +110,7 @@ impl Parse for Query {
             doc_comments.push(doc_comment_from_desc(&modifiers.desc.expr_list)?);
         }
 
-        Ok(Query { doc_comments, modifiers, name, key_pat, key_ty, return_ty })
+        Ok(QueryEntry::Query(Query { doc_comments, modifiers, name, key_pat, key_ty, return_ty }))
     }
 }
 
@@ -375,9 +401,9 @@ fn add_to_analyzer_stream(query: &Query, analyzer_stream: &mut proc_macro2::Toke
     // macro producing a higher order macro that has all its token in the macro declaration we lose
     // any meaningful spans, resulting in rust-analyzer being unable to make the connection between
     // the query name and the corresponding providers field. The trick to fix this is to have
-    // `rustc_queries` emit a field access with the given name's span which allows it to successfully
-    // show references / go to definition to the corresponding provider assignment which is usually
-    // the more interesting place.
+    // `rustc_queries` emit a field access with the given name's span which allows it to
+    // successfully show references / go to definition to the corresponding provider assignment
+    // which is usually the more interesting place.
     let ra_hint = quote! {
         let crate::query::Providers { #name: _, .. };
     };
@@ -393,9 +419,10 @@ fn add_to_analyzer_stream(query: &Query, analyzer_stream: &mut proc_macro2::Toke
 }
 
 pub(super) fn rustc_queries(input: TokenStream) -> TokenStream {
-    let queries = parse_macro_input!(input as List<Query>);
+    let queries = parse_macro_input!(input as List<QueryEntry>);
 
     let mut query_stream = quote! {};
+    let mut non_query_stream = quote! {};
     let mut helpers = HelperTokenStreams::default();
     let mut analyzer_stream = quote! {};
     let mut errors = quote! {};
@@ -411,6 +438,18 @@ pub(super) fn rustc_queries(input: TokenStream) -> TokenStream {
     }
 
     for query in queries.0 {
+        let query = match query {
+            QueryEntry::Query(query) => query,
+            QueryEntry::NonQuery(NonQuery { doc_comments, name }) => {
+                // Get the exceptional non-query case out of the way first.
+                non_query_stream.extend(quote! {
+                    #(#doc_comments)*
+                    #name,
+                });
+                continue;
+            }
+        };
+
         let Query { doc_comments, name, key_ty, return_ty, modifiers, .. } = &query;
 
         // Normalize an absent return type into `-> ()` to make macro-rules parsing easier.
@@ -486,24 +525,18 @@ pub(super) fn rustc_queries(input: TokenStream) -> TokenStream {
     let HelperTokenStreams { description_fns_stream, cache_on_disk_if_fns_stream } = helpers;
 
     TokenStream::from(quote! {
-        /// Higher-order macro that invokes the specified macro with a prepared
-        /// list of all query signatures (including modifiers).
-        ///
-        /// This allows multiple simpler macros to each have access to the list
-        /// of queries.
+        /// Higher-order macro that invokes the specified macro with (a) a list of all query
+        /// signatures (including modifiers), and (b) a list of non-query names. This allows
+        /// multiple simpler macros to each have access to these lists.
         #[macro_export]
         macro_rules! rustc_with_all_queries {
             (
-                // The macro to invoke once, on all queries (plus extras).
+                // The macro to invoke once, on all queries and non-queries.
                 $macro:ident!
-
-                // Within [], an optional list of extra "query" signatures to
-                // pass to the given macro, in addition to the actual queries.
-                $( [$($extra_fake_queries:tt)*] )?
             ) => {
                 $macro! {
-                    $( $($extra_fake_queries)* )?
-                    #query_stream
+                    queries { #query_stream }
+                    non_queries { #non_query_stream }
                 }
             }
         }
diff --git a/compiler/rustc_middle/src/dep_graph/dep_node.rs b/compiler/rustc_middle/src/dep_graph/dep_node.rs
@@ -265,18 +265,20 @@ impl StableOrd for WorkProductId {
 // Note: `$K` and `$V` are unused but present so this can be called by `rustc_with_all_queries`.
 macro_rules! define_dep_nodes {
     (
-        $(
-            $(#[$attr:meta])*
-            [$($modifiers:tt)*] fn $variant:ident($K:ty) -> $V:ty,
-        )*
-    ) => {
-
-        #[macro_export]
-        macro_rules! make_dep_kind_array {
-            ($mod:ident) => {[ $($mod::$variant()),* ]};
+        queries {
+            $(
+                $(#[$q_attr:meta])*
+                [$($modifiers:tt)*]
+                fn $q_name:ident($K:ty) -> $V:ty,
+            )*
         }
-
-        /// This enum serves as an index into arrays built by `make_dep_kind_array`.
+        non_queries {
+            $(
+                $(#[$nq_attr:meta])*
+                $nq_name:ident,
+            )*
+        }
+    ) => {
         // This enum has more than u8::MAX variants so we need some kind of multi-byte
         // encoding. The derived Encodable/Decodable uses leb128 encoding which is
         // dense when only considering this enum. But DepKind is encoded in a larger
@@ -285,14 +287,18 @@ macro_rules! define_dep_nodes {
         #[allow(non_camel_case_types)]
         #[repr(u16)] // Must be kept in sync with the rest of `DepKind`.
         pub enum DepKind {
-            $( $( #[$attr] )* $variant),*
+            $( $(#[$nq_attr])* $nq_name, )*
+            $( $(#[$q_attr])* $q_name, )*
         }
 
         // This computes the number of dep kind variants. Along the way, it sanity-checks that the
         // discriminants of the variants have been assigned consecutively from 0 so that they can
         // be used as a dense index, and that all discriminants fit in a `u16`.
         pub(crate) const DEP_KIND_NUM_VARIANTS: u16 = {
-            let deps = &[$(DepKind::$variant,)*];
+            let deps = &[
+                $(DepKind::$nq_name,)*
+                $(DepKind::$q_name,)*
+            ];
             let mut i = 0;
             while i < deps.len() {
                 if i != deps[i].as_usize() {
@@ -306,7 +312,8 @@ macro_rules! define_dep_nodes {
 
         pub(super) fn dep_kind_from_label_string(label: &str) -> Result<DepKind, ()> {
             match label {
-                $( stringify!($variant) => Ok(self::DepKind::$variant), )*
+                $( stringify!($nq_name) => Ok(self::DepKind::$nq_name), )*
+                $( stringify!($q_name) => Ok(self::DepKind::$q_name), )*
                 _ => Err(()),
             }
         }
@@ -315,27 +322,14 @@ macro_rules! define_dep_nodes {
         /// DepNode groups for tests.
         #[expect(non_upper_case_globals)]
         pub mod label_strs {
-            $( pub const $variant: &str = stringify!($variant); )*
+            $( pub const $nq_name: &str = stringify!($nq_name); )*
+            $( pub const $q_name: &str = stringify!($q_name); )*
         }
     };
 }
 
-// Create various data structures for each query, and also for a few things
-// that aren't queries. The key and return types aren't used, hence the use of `()`.
-rustc_with_all_queries!(define_dep_nodes![
-    /// We use this for most things when incr. comp. is turned off.
-    [] fn Null(()) -> (),
-    /// We use this to create a forever-red node.
-    [] fn Red(()) -> (),
-    /// We use this to create a side effect node.
-    [] fn SideEffect(()) -> (),
-    /// We use this to create the anon node with zero dependencies.
-    [] fn AnonZeroDeps(()) -> (),
-    [] fn TraitSelect(()) -> (),
-    [] fn CompileCodegenUnit(()) -> (),
-    [] fn CompileMonoItem(()) -> (),
-    [] fn Metadata(()) -> (),
-]);
+// Create various data structures for each query, and also for a few things that aren't queries.
+rustc_with_all_queries! { define_dep_nodes! }
 
 // WARNING: `construct` is generic and does not know that `CompileCodegenUnit` takes `Symbol`s as keys.
 // Be very careful changing this type signature!
diff --git a/compiler/rustc_middle/src/queries.rs b/compiler/rustc_middle/src/queries.rs
@@ -2771,6 +2771,23 @@ rustc_queries! {
         cache_on_disk_if { *cnum == LOCAL_CRATE }
         separate_provide_extern
     }
+
+    //-----------------------------------------------------------------------------
+    // "Non-queries" are special dep kinds that are not queries.
+    //-----------------------------------------------------------------------------
+
+    /// We use this for most things when incr. comp. is turned off.
+    non_query Null
+    /// We use this to create a forever-red node.
+    non_query Red
+    /// We use this to create a side effect node.
+    non_query SideEffect
+    /// We use this to create the anon node with zero dependencies.
+    non_query AnonZeroDeps
+    non_query TraitSelect
+    non_query CompileCodegenUnit
+    non_query CompileMonoItem
+    non_query Metadata
 }
 
 rustc_with_all_queries! { define_callbacks! }
diff --git a/compiler/rustc_middle/src/query/plumbing.rs b/compiler/rustc_middle/src/query/plumbing.rs
@@ -375,11 +375,15 @@ macro_rules! define_callbacks {
     (
         // You might expect the key to be `$K:ty`, but it needs to be `$($K:tt)*` so that
         // `query_helper_param_ty!` can match on specific type names.
-        $(
-            $(#[$attr:meta])*
-            [$($modifiers:tt)*]
-            fn $name:ident($($K:tt)*) -> $V:ty,
-        )*
+        queries {
+            $(
+                $(#[$attr:meta])*
+                [$($modifiers:tt)*]
+                fn $name:ident($($K:tt)*) -> $V:ty,
+            )*
+        }
+        // Non-queries are unused here.
+        non_queries { $($_:tt)* }
     ) => {
         $(
             #[allow(unused_lifetimes)]
diff --git a/compiler/rustc_query_impl/src/dep_kind_vtables.rs b/compiler/rustc_query_impl/src/dep_kind_vtables.rs
@@ -1,3 +1,4 @@
+use rustc_middle::arena::Arena;
 use rustc_middle::bug;
 use rustc_middle::dep_graph::{DepKindVTable, DepNodeKey, KeyFingerprintStyle};
 use rustc_middle::query::QueryCache;
@@ -124,24 +125,51 @@ where
     }
 }
 
-/// Helper module containing a [`DepKindVTable`] constructor for each dep kind,
-/// for use with [`rustc_middle::make_dep_kind_array`].
-///
-/// That macro will check that we gave it a constructor for every known dep kind.
-mod _dep_kind_vtable_ctors {
-    // Re-export all of the vtable constructors for non-query and query dep kinds.
-
-    // Non-query vtable constructors are defined in normal code.
-    pub(crate) use super::non_query::*;
-    // Query vtable constructors are defined via a macro.
-    pub(crate) use crate::_dep_kind_vtable_ctors_for_queries::*;
+macro_rules! define_dep_kind_vtables {
+    (
+        queries {
+            $(
+                $(#[$attr:meta])*
+                [$($modifiers:tt)*]
+                fn $name:ident($K:ty) -> $V:ty,
+            )*
+        }
+        non_queries {
+            $(
+                $(#[$nq_attr:meta])*
+                $nq_name:ident,
+            )*
+        }
+    ) => {{
+        // The small number of non-query vtables: `Null`, `Red`, etc.
+        let nq_vtables = [
+            $(
+                non_query::$nq_name(),
+            )*
+        ];
+
+        // The large number of query vtables.
+        let q_vtables: [DepKindVTable<'tcx>; _] = [
+            $(
+                $crate::dep_kind_vtables::make_dep_kind_vtable_for_query::<
+                    $crate::query_impl::$name::VTableGetter,
+                >(
+                    is_anon!([$($modifiers)*]),
+                    if_cache_on_disk!([$($modifiers)*] true false),
+                    is_eval_always!([$($modifiers)*]),
+                )
+            ),*
+        ];
+
+        (nq_vtables, q_vtables)
+    }}
 }
 
-pub fn make_dep_kind_vtables<'tcx>(
-    arena: &'tcx rustc_middle::arena::Arena<'tcx>,
-) -> &'tcx [DepKindVTable<'tcx>] {
-    // Create an array of vtables, one for each dep kind (non-query and query).
-    let dep_kind_vtables: [DepKindVTable<'tcx>; _] =
-        rustc_middle::make_dep_kind_array!(_dep_kind_vtable_ctors);
-    arena.alloc_from_iter(dep_kind_vtables)
+// Create an array of vtables, one for each dep kind (non-query and query).
+pub fn make_dep_kind_vtables<'tcx>(arena: &'tcx Arena<'tcx>) -> &'tcx [DepKindVTable<'tcx>] {
+    let (nq_vtables, q_vtables) =
+        rustc_middle::rustc_with_all_queries! { define_dep_kind_vtables! };
+
+    // Non-query vtables must come before query vtables, to match the order of `DepKind`.
+    arena.alloc_from_iter(nq_vtables.into_iter().chain(q_vtables.into_iter()))
 }
diff --git a/compiler/rustc_query_impl/src/plumbing.rs b/compiler/rustc_query_impl/src/plumbing.rs
@@ -414,15 +414,20 @@ pub(crate) fn force_from_dep_node_inner<'tcx, Q: GetQueryVTable<'tcx>>(
     }
 }
 
-// Note: `$K` and `$V` are unused but present so this can be called by `rustc_with_all_queries`.
 macro_rules! define_queries {
     (
-        $(
-            $(#[$attr:meta])*
-            [$($modifiers:tt)*] fn $name:ident($K:ty) -> $V:ty,
-        )*
+        // Note: `$K` and `$V` are unused but present so this can be called by
+        // `rustc_with_all_queries`.
+        queries {
+            $(
+                $(#[$attr:meta])*
+                [$($modifiers:tt)*]
+                fn $name:ident($K:ty) -> $V:ty,
+            )*
+        }
+        // Non-queries are unused here.
+        non_queries { $($_:tt)* }
     ) => {
-
         pub(crate) mod query_impl { $(pub(crate) mod $name {
             use super::super::*;
             use ::rustc_middle::query::erase::{self, Erased};
@@ -689,23 +694,5 @@ macro_rules! define_queries {
                 })
             }
         }
-
-        /// Declares a dep-kind vtable constructor for each query.
-        mod _dep_kind_vtable_ctors_for_queries {
-            use ::rustc_middle::dep_graph::DepKindVTable;
-            use $crate::dep_kind_vtables::make_dep_kind_vtable_for_query;
-
-            $(
-                /// `DepKindVTable` constructor for this query.
-                pub(crate) fn $name<'tcx>() -> DepKindVTable<'tcx> {
-                    use $crate::query_impl::$name::VTableGetter;
-                    make_dep_kind_vtable_for_query::<VTableGetter>(
-                        is_anon!([$($modifiers)*]),
-                        if_cache_on_disk!([$($modifiers)*] true false),
-                        is_eval_always!([$($modifiers)*]),
-                    )
-                }
-            )*
-        }
     }
 }
