Auto merge of #109611 - Zoxc:query-engine-rem, r=cjgillot

Remove `QueryEngine` trait

This removes the `QueryEngine` trait and `Queries` from `rustc_query_impl` and replaced them with function pointers and fields in `QuerySystem`. As a side effect `OnDiskCache` is moved back into `rustc_middle` and the `OnDiskCache` trait is also removed.

This has a couple of benefits.
- `TyCtxt` is used in the query system instead of the removed `QueryCtxt` which is larger.
- Function pointers are more flexible to work with. A variant of https://github.com/rust-lang/rust/pull/107802 is included which avoids the double indirection. For https://github.com/rust-lang/rust/pull/108938 we can name entry point `__rust_end_short_backtrace` to avoid some overhead. For https://github.com/rust-lang/rust/pull/108062 it avoids the duplicate `QueryEngine` structs.
- `QueryContext` now implements `DepContext` which avoids many `dep_context()` calls in `rustc_query_system`.
- The `rustc_driver` size is reduced by 0.33%, hopefully that means some bootstrap improvements.
- This avoids the unsafe code around the `QueryEngine` trait.

r? `@cjgillot`

1 files changed, 1 insertions, 1 deletions

diff --git a/compiler/rustc_query_system/src/query/plumbing.rs b/compiler/rustc_query_system/src/query/plumbing.rs
index bce01debc53..3b17c665fb7 100644
--- a/compiler/rustc_query_system/src/query/plumbing.rs
+++ b/compiler/rustc_query_system/src/query/plumbing.rs
@@ -236,7 +236,7 @@ pub(crate) struct CycleError<D: DepKind> {
 /// It returns the shard index and a lock guard to the shard,
 /// which will be used if the query is not in the cache and we need
 /// to compute it.
-#[inline]
+#[inline(always)]
 pub fn try_get_cached<Tcx, C>(tcx: Tcx, cache: &C, key: &C::Key) -> Option<C::Value>
 where
     C: QueryCache,