Rollup merge of #152515 - Zalathar:dep-kind-vtables, r=nnethercote

Extract `DepKindVTable` constructors to their own module

This is a fairly substantial chunk of code in `rustc_query_impl::plumbing` that mostly doesn't need to be inside a macro at all.

The part that does need to be in a macro is the declaration of a named vtable constructor function for each query. I have extracted that into its own separate call to `rustc_middle::rustc_with_all_queries!` in the new module, so that dep-kind vtable construction is almost entirely confined to `rustc_query_impl::dep_kind_vtables`.

There should be no change to compiler behaviour.

r? nnethercote (or compiler)

Author: JonathanBrouwer

compiler/rustc_query_impl/src/dep_kind_vtables.rs

@@ -0,0 +1,174 @@
+use rustc_middle::bug;
+use rustc_middle::dep_graph::DepKindVTable;
+use rustc_middle::ty::TyCtxt;
+use rustc_query_system::dep_graph::{DepNodeKey, FingerprintStyle};
+use rustc_query_system::query::QueryCache;
+
+use crate::plumbing::{force_from_dep_node_inner, try_load_from_on_disk_cache_inner};
+use crate::{QueryCtxt, QueryDispatcherUnerased, QueryFlags};
+
+/// [`DepKindVTable`] constructors for special dep kinds that aren't queries.
+#[expect(non_snake_case, reason = "use non-snake case to avoid collision with query names")]
+mod non_query {
+    use super::*;
+
+    // We use this for most things when incr. comp. is turned off.
+    pub(crate) fn Null<'tcx>() -> DepKindVTable<'tcx> {
+        DepKindVTable {
+            is_anon: false,
+            is_eval_always: false,
+            fingerprint_style: FingerprintStyle::Unit,
+            force_from_dep_node: Some(|_, dep_node, _| {
+                bug!("force_from_dep_node: encountered {dep_node:?}")
+            }),
+            try_load_from_on_disk_cache: None,
+            name: &"Null",
+        }
+    }
+
+    // We use this for the forever-red node.
+    pub(crate) fn Red<'tcx>() -> DepKindVTable<'tcx> {
+        DepKindVTable {
+            is_anon: false,
+            is_eval_always: false,
+            fingerprint_style: FingerprintStyle::Unit,
+            force_from_dep_node: Some(|_, dep_node, _| {
+                bug!("force_from_dep_node: encountered {dep_node:?}")
+            }),
+            try_load_from_on_disk_cache: None,
+            name: &"Red",
+        }
+    }
+
+    pub(crate) fn SideEffect<'tcx>() -> DepKindVTable<'tcx> {
+        DepKindVTable {
+            is_anon: false,
+            is_eval_always: false,
+            fingerprint_style: FingerprintStyle::Unit,
+            force_from_dep_node: Some(|tcx, _, prev_index| {
+                tcx.dep_graph.force_diagnostic_node(QueryCtxt::new(tcx), prev_index);
+                true
+            }),
+            try_load_from_on_disk_cache: None,
+            name: &"SideEffect",
+        }
+    }
+
+    pub(crate) fn AnonZeroDeps<'tcx>() -> DepKindVTable<'tcx> {
+        DepKindVTable {
+            is_anon: true,
+            is_eval_always: false,
+            fingerprint_style: FingerprintStyle::Opaque,
+            force_from_dep_node: Some(|_, _, _| bug!("cannot force an anon node")),
+            try_load_from_on_disk_cache: None,
+            name: &"AnonZeroDeps",
+        }
+    }
+
+    pub(crate) fn TraitSelect<'tcx>() -> DepKindVTable<'tcx> {
+        DepKindVTable {
+            is_anon: true,
+            is_eval_always: false,
+            fingerprint_style: FingerprintStyle::Unit,
+            force_from_dep_node: None,
+            try_load_from_on_disk_cache: None,
+            name: &"TraitSelect",
+        }
+    }
+
+    pub(crate) fn CompileCodegenUnit<'tcx>() -> DepKindVTable<'tcx> {
+        DepKindVTable {
+            is_anon: false,
+            is_eval_always: false,
+            fingerprint_style: FingerprintStyle::Opaque,
+            force_from_dep_node: None,
+            try_load_from_on_disk_cache: None,
+            name: &"CompileCodegenUnit",
+        }
+    }
+
+    pub(crate) fn CompileMonoItem<'tcx>() -> DepKindVTable<'tcx> {
+        DepKindVTable {
+            is_anon: false,
+            is_eval_always: false,
+            fingerprint_style: FingerprintStyle::Opaque,
+            force_from_dep_node: None,
+            try_load_from_on_disk_cache: None,
+            name: &"CompileMonoItem",
+        }
+    }
+
+    pub(crate) fn Metadata<'tcx>() -> DepKindVTable<'tcx> {
+        DepKindVTable {
+            is_anon: false,
+            is_eval_always: false,
+            fingerprint_style: FingerprintStyle::Unit,
+            force_from_dep_node: None,
+            try_load_from_on_disk_cache: None,
+            name: &"Metadata",
+        }
+    }
+}
+
+/// Shared implementation of the [`DepKindVTable`] constructor for queries.
+/// Called from macro-generated code for each query.
+pub(crate) fn make_dep_kind_vtable_for_query<'tcx, Q, Cache, const FLAGS: QueryFlags>(
+    is_eval_always: bool,
+) -> DepKindVTable<'tcx>
+where
+    Q: QueryDispatcherUnerased<'tcx, Cache, FLAGS>,
+    Cache: QueryCache + 'tcx,
+{
+    let is_anon = FLAGS.is_anon;
+    let fingerprint_style = if is_anon {
+        FingerprintStyle::Opaque
+    } else {
+        <Cache::Key as DepNodeKey<TyCtxt<'tcx>>>::fingerprint_style()
+    };
+
+    if is_anon || !fingerprint_style.reconstructible() {
+        return DepKindVTable {
+            is_anon,
+            is_eval_always,
+            fingerprint_style,
+            force_from_dep_node: None,
+            try_load_from_on_disk_cache: None,
+            name: Q::NAME,
+        };
+    }
+
+    DepKindVTable {
+        is_anon,
+        is_eval_always,
+        fingerprint_style,
+        force_from_dep_node: Some(|tcx, dep_node, _| {
+            force_from_dep_node_inner(Q::query_dispatcher(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)
+        }),
+        name: Q::NAME,
+    }
+}
+
+/// 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::*;
+}
+
+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)
+}

compiler/rustc_query_impl/src/lib.rs

@@ -12,8 +12,7 @@
 use std::marker::ConstParamTy;
 
 use rustc_data_structures::sync::AtomicU64;
-use rustc_middle::arena::Arena;
-use rustc_middle::dep_graph::{self, DepKind, DepKindVTable, DepNode, DepNodeIndex};
+use rustc_middle::dep_graph::{self, DepKind, DepNode, DepNodeIndex};
 use rustc_middle::queries::{
     self, ExternProviders, Providers, QueryCaches, QueryEngine, QueryStates,
 };
@@ -27,18 +26,21 @@ use rustc_query_system::query::{
 };
 use rustc_span::{ErrorGuaranteed, Span};
 
+pub use crate::dep_kind_vtables::make_dep_kind_vtables;
 pub use crate::job::{QueryJobMap, break_query_cycles, print_query_stack};
 pub use crate::plumbing::{QueryCtxt, query_key_hash_verify_all};
 use crate::plumbing::{encode_all_query_results, try_mark_green};
 use crate::profiling_support::QueryKeyStringCache;
 pub use crate::profiling_support::alloc_self_profile_query_strings;
 use crate::values::Value;
 
+#[macro_use]
+mod plumbing;
+
+mod dep_kind_vtables;
 mod error;
 mod execution;
 mod job;
-#[macro_use]
-mod plumbing;
 mod profiling_support;
 mod values;