Auto merge of #122627 - RalfJung:collector-stack-space, r=<try>

collector: move ensure_sufficient_stack out of the loop

According to the docs this call has some overhead to putting it inside the loop doesn't seem like a good idea.

r? `@oli-obk`

compiler/rustc_monomorphize/src/collector.rs

@@ -1433,7 +1433,7 @@ fn create_mono_items_for_default_impls<'tcx>(
     }
 }
 
-/// Scans the CTFE alloc in order to find function calls, closures, and drop-glue.
+/// Scans the CTFE alloc in order to find function pointers and statics that must be monomorphized.
 fn collect_alloc<'tcx>(tcx: TyCtxt<'tcx>, alloc_id: AllocId, output: &mut MonoItems<'tcx>) {
     match tcx.global_alloc(alloc_id) {
         GlobalAlloc::Static(def_id) => {
@@ -1446,11 +1446,11 @@ fn collect_alloc<'tcx>(tcx: TyCtxt<'tcx>, alloc_id: AllocId, output: &mut MonoIt
         }
         GlobalAlloc::Memory(alloc) => {
             trace!("collecting {:?} with {:#?}", alloc_id, alloc);
-            for &prov in alloc.inner().provenance().ptrs().values() {
-                rustc_data_structures::stack::ensure_sufficient_stack(|| {
+            rustc_data_structures::stack::ensure_sufficient_stack(move || {
+                for &prov in alloc.inner().provenance().ptrs().values() {
                     collect_alloc(tcx, prov.alloc_id(), output);
-                });
-            }
+                }
+            });
         }
         GlobalAlloc::Function(fn_instance) => {
             if should_codegen_locally(tcx, &fn_instance) {