Auto merge of #108300 - oli-obk:elsa, r=eholk

Use a lock-free datastructure for source_span

follow up to the perf regression in https://github.com/rust-lang/rust/pull/105462

The main regression is likely the CStore, but let's evaluate the perf impact of this on its own

1 files changed, 2 insertions, 3 deletions

diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 27f069275cf..7e6a6e71670 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -1030,7 +1030,7 @@ impl<'tcx> TyCtxt<'tcx> {
     /// system if the result is otherwise tracked through queries
     #[inline]
     pub fn source_span_untracked(self, def_id: LocalDefId) -> Span {
-        self.untracked.source_span.read().get(def_id).copied().unwrap_or(DUMMY_SP)
+        self.untracked.source_span.get(def_id).unwrap_or(DUMMY_SP)
     }
 
     #[inline(always)]
@@ -2525,6 +2525,5 @@ pub fn provide(providers: &mut ty::query::Providers) {
         // We want to check if the panic handler was defined in this crate
         tcx.lang_items().panic_impl().map_or(false, |did| did.is_local())
     };
-    providers.source_span =
-        |tcx, def_id| tcx.untracked.source_span.read().get(def_id).copied().unwrap_or(DUMMY_SP);
+    providers.source_span = |tcx, def_id| tcx.untracked.source_span.get(def_id).unwrap_or(DUMMY_SP);
 }