Split coroutine layout computation to its own file

compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs

@@ -328,7 +328,8 @@ fn build_coroutine_variant_struct_type_di_node<'ll, 'tcx>(
                 .map(|field_index| {
                     let coroutine_saved_local = coroutine_layout.variant_fields[variant_index]
                         [FieldIdx::from_usize(field_index)];
-                    let field_name_maybe = coroutine_layout.field_names[coroutine_saved_local];
+                    let field_name_maybe =
+                        coroutine_layout.field_tys[coroutine_saved_local].debuginfo_name;
                     let field_name = field_name_maybe
                         .as_ref()
                         .map(|s| Cow::from(s.as_str()))

compiler/rustc_middle/src/mir/pretty.rs

@@ -429,9 +429,9 @@ fn write_scope_tree(
 
     // Coroutine debuginfo.
     if let Some(layout) = body.coroutine_layout_raw() {
-        for (field, name) in layout.field_names.iter_enumerated() {
-            let source_info = layout.field_tys[field].source_info;
-            if let Some(name) = name
+        for (field, field_decl) in layout.field_tys.iter_enumerated() {
+            let source_info = field_decl.source_info;
+            if let Some(name) = field_decl.debuginfo_name
                 && source_info.scope == parent
             {
                 let indented_debug_info =
@@ -559,17 +559,12 @@ fn write_coroutine_layout<'tcx>(
     w: &mut dyn io::Write,
     options: PrettyPrintMirOptions,
 ) -> io::Result<()> {
-    let CoroutineLayout {
-        field_tys,
-        field_names: _, // Dumped in scope tree with debug info.
-        variant_fields,
-        variant_source_info,
-        storage_conflicts,
-    } = layout;
+    let CoroutineLayout { field_tys, variant_fields, variant_source_info, storage_conflicts } =
+        layout;
 
     writeln!(w, "{INDENT}coroutine layout {{")?;
 
-    for (field, CoroutineSavedTy { ty, source_info, ignore_for_traits }) in
+    for (field, CoroutineSavedTy { ty, source_info, ignore_for_traits, debuginfo_name: _ }) in
         field_tys.iter_enumerated()
     {
         let ignore_for_traits = if *ignore_for_traits { " (ignored for traits)" } else { "" };

compiler/rustc_middle/src/mir/query.rs

@@ -27,6 +27,8 @@ pub struct CoroutineSavedTy<'tcx> {
     pub source_info: SourceInfo,
     /// Whether the local should be ignored for trait bound computations.
     pub ignore_for_traits: bool,
+    /// The name for debuginfo.
+    pub debuginfo_name: Option<Symbol>,
 }
 
 /// The layout of coroutine state.
@@ -36,9 +38,6 @@ pub struct CoroutineLayout<'tcx> {
     /// The type of every local stored inside the coroutine.
     pub field_tys: IndexVec<CoroutineSavedLocal, CoroutineSavedTy<'tcx>>,
 
-    /// The name for debuginfo.
-    pub field_names: IndexVec<CoroutineSavedLocal, Option<Symbol>>,
-
     /// Which of the above fields are in each variant. Note that one field may
     /// be stored in multiple variants.
     pub variant_fields: IndexVec<VariantIdx, IndexVec<FieldIdx, CoroutineSavedLocal>>,

compiler/rustc_middle/src/ty/mod.rs

@@ -1929,7 +1929,6 @@ impl<'tcx> TyCtxt<'tcx> {
                     iter::repeat(source_info).take(CoroutineArgs::RESERVED_VARIANTS).collect();
                 let proxy_layout = CoroutineLayout {
                     field_tys: [].into(),
-                    field_names: [].into(),
                     variant_fields,
                     variant_source_info,
                     storage_conflicts: BitMatrix::new(0, 0),