Auto merge of #78452 - cjgillot:ddk-struct, r=Mark-Simulacrum

Access query (DepKind) metadata through fields

This refactors the access to query definition metadata (attributes such as eval always, anon, has_params) and loading/forcing functions to generate a number of structs, instead of matching on the DepKind enum. This makes access to the fields cheaper to compile. Using a struct means that finding the metadata for a given query is just an offset away; previously the match may have been compiled to a jump table but likely not completely inlined as we expect here.

A previous attempt explored a similar strategy, but using trait objects in #78314 that proved less effective, likely due to higher overheads due to forcing dynamic calls and poorer cache utilization (all metadata is fairly densely packed with this PR).

2 files changed, 1 insertions, 7 deletions

diff --git a/compiler/rustc_query_system/src/dep_graph/dep_node.rs b/compiler/rustc_query_system/src/dep_graph/dep_node.rs
index ff52fdab19c..64aba870502 100644
--- a/compiler/rustc_query_system/src/dep_graph/dep_node.rs
+++ b/compiler/rustc_query_system/src/dep_graph/dep_node.rs
@@ -153,12 +153,6 @@ where
     }
 }
 
-impl<Ctxt: DepContext> DepNodeParams<Ctxt> for () {
-    fn to_fingerprint(&self, _: Ctxt) -> Fingerprint {
-        Fingerprint::ZERO
-    }
-}
-
 /// A "work product" corresponds to a `.o` (or other) file that we
 /// save in between runs. These IDs do not have a `DefId` but rather
 /// some independent path or string that persists between runs without
diff --git a/compiler/rustc_query_system/src/dep_graph/mod.rs b/compiler/rustc_query_system/src/dep_graph/mod.rs
index da0b5aad6c8..b1c901633a7 100644
--- a/compiler/rustc_query_system/src/dep_graph/mod.rs
+++ b/compiler/rustc_query_system/src/dep_graph/mod.rs
@@ -61,7 +61,7 @@ pub trait DepContext: Copy {
 }
 
 /// Describe the different families of dependency nodes.
-pub trait DepKind: Copy + fmt::Debug + Eq + Ord + Hash {
+pub trait DepKind: Copy + fmt::Debug + Eq + Hash {
     const NULL: Self;
 
     /// Return whether this kind always require evaluation.