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, 4 deletions

diff --git a/compiler/rustc_interface/src/queries.rs b/compiler/rustc_interface/src/queries.rs
index c957578b59e..a96cc95a384 100644
--- a/compiler/rustc_interface/src/queries.rs
+++ b/compiler/rustc_interface/src/queries.rs
@@ -7,11 +7,10 @@ use rustc_codegen_ssa::traits::CodegenBackend;
 use rustc_codegen_ssa::CodegenResults;
 use rustc_data_structures::steal::Steal;
 use rustc_data_structures::svh::Svh;
-use rustc_data_structures::sync::{Lrc, OnceCell, RwLock, WorkerLocal};
+use rustc_data_structures::sync::{AppendOnlyVec, Lrc, OnceCell, RwLock, WorkerLocal};
 use rustc_hir::def_id::{CRATE_DEF_ID, LOCAL_CRATE};
 use rustc_hir::definitions::Definitions;
 use rustc_incremental::DepGraphFuture;
-use rustc_index::vec::IndexVec;
 use rustc_lint::LintStore;
 use rustc_metadata::creader::CStore;
 use rustc_middle::arena::Arena;
@@ -195,10 +194,9 @@ impl<'tcx> Queries<'tcx> {
 
             let cstore = RwLock::new(Box::new(CStore::new(sess)) as _);
             let definitions = RwLock::new(Definitions::new(sess.local_stable_crate_id()));
-            let mut source_span = IndexVec::default();
+            let source_span = AppendOnlyVec::new();
             let _id = source_span.push(krate.spans.inner_span);
             debug_assert_eq!(_id, CRATE_DEF_ID);
-            let source_span = RwLock::new(source_span);
             let untracked = Untracked { cstore, source_span, definitions };
 
             let qcx = passes::create_global_ctxt(