Weaken assert_dep_node_not_yet_allocated_in_current_session for multiple threads

compiler/rustc_codegen_ssa/src/base.rs

@@ -1111,7 +1111,7 @@ pub fn determine_cgu_reuse<'tcx>(tcx: TyCtxt<'tcx>, cgu: &CodegenUnit<'tcx>) ->
     // know that later). If we are not doing LTO, there is only one optimized
     // version of each module, so we re-use that.
     let dep_node = cgu.codegen_dep_node(tcx);
-    tcx.dep_graph.assert_dep_node_not_yet_allocated_in_current_session(&dep_node, || {
+    tcx.dep_graph.assert_dep_node_not_yet_allocated_in_current_session(tcx.sess, &dep_node, || {
         format!(
             "CompileCodegenUnit dep-node for CGU `{}` already exists before marking.",
             cgu.name()

compiler/rustc_query_system/src/dep_graph/graph.rs

@@ -336,13 +336,17 @@ impl<D: Deps> DepGraphData<D> {
         //    in `DepGraph::try_mark_green()`.
         // 2. Two distinct query keys get mapped to the same `DepNode`
         //    (see for example #48923).
-        self.assert_dep_node_not_yet_allocated_in_current_session(&key, || {
-            format!(
-                "forcing query with already existing `DepNode`\n\
+        self.assert_dep_node_not_yet_allocated_in_current_session(
+            cx.dep_context().sess(),
+            &key,
+            || {
+                format!(
+                    "forcing query with already existing `DepNode`\n\
                  - query-key: {arg:?}\n\
                  - dep-node: {key:?}"
-            )
-        });
+                )
+            },
+        );
 
         let with_deps = |task_deps| D::with_deps(task_deps, || task(cx, arg));
         let (result, edges) = if cx.dep_context().is_eval_always(key.kind) {
@@ -627,12 +631,20 @@ impl<D: Deps> DepGraph<D> {
 impl<D: Deps> DepGraphData<D> {
     fn assert_dep_node_not_yet_allocated_in_current_session<S: std::fmt::Display>(
         &self,
+        sess: &Session,
         dep_node: &DepNode,
         msg: impl FnOnce() -> S,
     ) {
         if let Some(prev_index) = self.previous.node_to_index_opt(dep_node) {
-            let current = self.colors.get(prev_index);
-            assert_matches!(current, DepNodeColor::Unknown, "{}", msg())
+            let color = self.colors.get(prev_index);
+            let ok = match color {
+                DepNodeColor::Unknown => true,
+                DepNodeColor::Red => false,
+                DepNodeColor::Green(..) => sess.threads() > 1, // Other threads may mark this green
+            };
+            if !ok {
+                panic!("{}", msg())
+            }
         } else if let Some(nodes_in_current_session) = &self.current.nodes_in_current_session {
             outline(|| {
                 let seen = nodes_in_current_session.lock().contains_key(dep_node);
@@ -1035,11 +1047,12 @@ impl<D: Deps> DepGraph<D> {
 
     pub fn assert_dep_node_not_yet_allocated_in_current_session<S: std::fmt::Display>(
         &self,
+        sess: &Session,
         dep_node: &DepNode,
         msg: impl FnOnce() -> S,
     ) {
         if let Some(data) = &self.data {
-            data.assert_dep_node_not_yet_allocated_in_current_session(dep_node, msg)
+            data.assert_dep_node_not_yet_allocated_in_current_session(sess, dep_node, msg)
         }
     }