Rollup merge of rust-lang#50964 - michaelwoerister:query-symbol-names, r=nikomatsakis

Make sure that queries have predictable symbol names.

Some recent refactorings led to query names not showing up in the corresponding symbol names. [perf-focus](https://github.com/nikomatsakis/perf-focus) and manual profiling have been broken by this. This PR makes sure that query providers always get their own symbol and that that symbol has a predictable name.

Since this adds `#[inline(never)]` to a function that wraps the provider call, let's check if this does not regress performance before merging.

r? @nikomatsakis

Author: kennytm

src/librustc/ty/maps/plumbing.rs

@@ -701,6 +701,16 @@ macro_rules! define_maps {
             })*
         }
 
+        // This module and the functions in it exist only to provide a
+        // predictable symbol name prefix for query providers. This is helpful
+        // for analyzing queries in profilers.
+        pub(super) mod __query_compute {
+            $(#[inline(never)]
+            pub fn $name<F: FnOnce() -> R, R>(f: F) -> R {
+                f()
+            })*
+        }
+
         $(impl<$tcx> QueryConfig<$tcx> for queries::$name<$tcx> {
             type Key = $K;
             type Value = $V;
@@ -722,9 +732,12 @@ macro_rules! define_maps {
                 DepNode::new(tcx, $node(*key))
             }
 
+            #[inline]
             fn compute(tcx: TyCtxt<'_, 'tcx, '_>, key: Self::Key) -> Self::Value {
-                let provider = tcx.maps.providers[key.map_crate()].$name;
-                provider(tcx.global_tcx(), key)
+                __query_compute::$name(move || {
+                    let provider = tcx.maps.providers[key.map_crate()].$name;
+                    provider(tcx.global_tcx(), key)
+                })
             }
 
             fn handle_cycle_error(tcx: TyCtxt<'_, 'tcx, '_>) -> Self::Value {