transpile: Translate enums with newtype structs

c2rust-ast-exporter/src/AstExporter.cpp

@@ -2625,11 +2625,16 @@ class TranslateASTVisitor final
 
 void TypeEncoder::VisitEnumType(const EnumType *T) {
     auto ed = T->getDecl()->getDefinition();
+
+    if (!ed) {
+        ed = T->getDecl()->getCanonicalDecl();
+    }
+
     encodeType(T, TagEnumType, [T, ed](CborEncoder *local) {
         cbor_encode_uint(local, uintptr_t(ed));
     });
 
-    if (ed != nullptr) astEncoder->TraverseDecl(ed);
+    astEncoder->TraverseDecl(ed);
 }
 
 void TypeEncoder::VisitRecordType(const RecordType *T) {

c2rust-refactor/src/transform/items.rs

@@ -145,6 +145,15 @@ impl Transform for RenameUnnamed {
             renamer
                 .new_idents
                 .insert(cx.hir_map().node_to_hir_id(i.id), new_name);
+
+            if let ItemKind::Struct(variant_data, _) | ItemKind::Union(variant_data, _) = &i.kind {
+                if let Some(ctor_id) = variant_data.ctor_id() {
+                    renamer
+                        .new_idents
+                        .insert(cx.hir_map().node_to_hir_id(ctor_id), new_name);
+                }
+            }
+
             renamer.new_to_old.insert(new_name, i.ident);
             counter += 1;
             smallvec![i.map(|i| Item {

c2rust-refactor/src/transform/reorganize_definitions.rs

@@ -12,7 +12,7 @@ use rustc_ast::*;
 use rustc_ast_pretty::pprust::{self, item_to_string, PrintState};
 use rustc_data_structures::map_in_place::MapInPlace;
 use rustc_hir::def::{DefKind, Namespace, PerNS, Res};
-use rustc_hir::def_id::DefId;
+use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::{self as hir, Node};
 use rustc_middle::metadata::ModChild;
 use rustc_middle::ty::{self, ParamEnv};
@@ -122,6 +122,7 @@ impl<'a, 'tcx> Reorganizer<'a, 'tcx> {
         self.update_module_info_items(krate);
 
         self.move_items(header_decls, krate);
+        self.add_ctor_mappings();
 
         self.update_paths(krate)
     }
@@ -765,6 +766,42 @@ impl<'a, 'tcx> Reorganizer<'a, 'tcx> {
         });
     }
 
+    fn add_ctor_mappings(&mut self) {
+        let get_ctor = |def_id: DefId| -> Option<LocalDefId> {
+            self.cx.hir_map().get_if_local(def_id).and_then(|node| {
+                let item = match node {
+                    hir::Node::Item(item) => item,
+                    _ => return None,
+                };
+                let hir_id = match &item.kind {
+                    hir::ItemKind::Struct(variant_data, _)
+                    | hir::ItemKind::Union(variant_data, _) => variant_data.ctor_hir_id()?,
+                    _ => return None,
+                };
+                self.cx.hir_map().opt_local_def_id(hir_id)
+            })
+        };
+
+        let ctor_mapping: HashMap<DefId, Replacement> = self
+            .path_mapping
+            .iter()
+            .filter_map(|(&def_id, replacement)| {
+                Some((
+                    get_ctor(def_id)?.to_def_id(),
+                    Replacement {
+                        def: replacement
+                            .def
+                            .and_then(|def| get_ctor(def))
+                            .map(LocalDefId::to_def_id),
+                        ..replacement.clone()
+                    },
+                ))
+            })
+            .collect();
+
+        self.path_mapping.extend(ctor_mapping);
+    }
+
     /// Update paths to moved items and remove redundant imports.
     fn update_paths(&self, krate: &mut Crate) {
         let tcx = self.cx.ty_ctxt();

c2rust-transpile/src/c_ast/mod.rs

@@ -996,6 +996,54 @@ impl TypedAstContext {
         }
     }
 
+    /// Identifies typedefs that name unnamed types.
+    /// Later, the two declarations can be collapsed into a single name and declaration,
+    /// eliminating the typedef altogether.
+    pub fn set_prenamed_decls(&mut self) {
+        let mut prenamed_decls: IndexMap<CDeclId, CDeclId> = IndexMap::new();
+
+        for (&decl_id, decl) in self.iter_decls() {
+            if let CDeclKind::Typedef { ref name, typ, .. } = decl.kind {
+                if let Some(subdecl_id) = self.resolve_type(typ.ctype).kind.as_underlying_decl() {
+                    use CDeclKind::*;
+                    let is_unnamed = match self[subdecl_id].kind {
+                        Struct { name: None, .. }
+                        | Union { name: None, .. }
+                        | Enum { name: None, .. } => true,
+
+                        // Detect case where typedef and struct share the same name.
+                        // In this case the purpose of the typedef was simply to eliminate
+                        // the need for the 'struct' tag when referring to the type name.
+                        Struct {
+                            name: Some(ref target_name),
+                            ..
+                        }
+                        | Union {
+                            name: Some(ref target_name),
+                            ..
+                        }
+                        | Enum {
+                            name: Some(ref target_name),
+                            ..
+                        } => name == target_name,
+
+                        _ => false,
+                    };
+
+                    if is_unnamed
+                        && !prenamed_decls
+                            .values()
+                            .any(|decl_id| *decl_id == subdecl_id)
+                    {
+                        prenamed_decls.insert(decl_id, subdecl_id);
+                    }
+                }
+            }
+        }
+
+        self.prenamed_decls = prenamed_decls;
+    }
+
     pub fn prune_unwanted_decls(&mut self, want_unused_functions: bool) {
         // Starting from a set of root declarations, walk each one to find declarations it
         // depends on. Then walk each of those, recursively.
@@ -1105,19 +1153,20 @@ impl TypedAstContext {
             }
         }
 
-        // Unset c_main if we are not retaining its declaration
-        if let Some(main_id) = self.c_main {
-            if !wanted.contains(&main_id) {
-                self.c_main = None;
-            }
-        }
-
         // Prune any declaration that isn't considered live
         self.c_decls
             .retain(|&decl_id, _decl| wanted.contains(&decl_id));
 
-        // Prune top declarations that are not considered live
-        self.c_decls_top.retain(|x| wanted.contains(x));
+        // Remove references to removed decls that are held elsewhere.
+        self.c_decls_top.retain(|x| self.c_decls.contains_key(x));
+        self.prenamed_decls
+            .retain(|x, _| self.c_decls.contains_key(x));
+
+        if let Some(main_id) = self.c_main {
+            if !self.c_decls.contains_key(&main_id) {
+                self.c_main = None;
+            }
+        }
     }
 
     /// Bubble types of unary and binary operators up from their args into the expression type.
@@ -1803,37 +1852,46 @@ impl CastKind {
 
             (CTypeKind::Function(..), CTypeKind::Pointer(..)) => CastKind::FunctionToPointerDecay,
 
-            (_, CTypeKind::Pointer(..)) if source_ty_kind.is_integral_type() => {
+            (_, CTypeKind::Pointer(..)) if source_ty_kind.is_enum_or_integral_type() => {
                 CastKind::IntegralToPointer
             }
 
             (CTypeKind::Pointer(..), CTypeKind::Bool) => CastKind::PointerToBoolean,
 
-            (CTypeKind::Pointer(..), _) if target_ty_kind.is_integral_type() => {
+            (CTypeKind::Pointer(..), _) if target_ty_kind.is_enum_or_integral_type() => {
                 CastKind::PointerToIntegral
             }
 
-            (_, CTypeKind::Bool) if source_ty_kind.is_integral_type() => {
+            (_, CTypeKind::Bool) if source_ty_kind.is_enum_or_integral_type() => {
                 CastKind::IntegralToBoolean
             }
 
             (CTypeKind::Bool, _) if target_ty_kind.is_signed_integral_type() => {
                 CastKind::BooleanToSignedIntegral
             }
 
-            (_, _) if source_ty_kind.is_integral_type() && target_ty_kind.is_integral_type() => {
+            (_, _)
+                if source_ty_kind.is_enum_or_integral_type()
+                    && target_ty_kind.is_enum_or_integral_type() =>
+            {
                 CastKind::IntegralCast
             }
 
-            (_, _) if source_ty_kind.is_integral_type() && target_ty_kind.is_floating_type() => {
+            (_, _)
+                if source_ty_kind.is_enum_or_integral_type()
+                    && target_ty_kind.is_floating_type() =>
+            {
                 CastKind::IntegralToFloating
             }
 
             (_, CTypeKind::Bool) if source_ty_kind.is_floating_type() => {
                 CastKind::FloatingToBoolean
             }
 
-            (_, _) if source_ty_kind.is_floating_type() && target_ty_kind.is_integral_type() => {
+            (_, _)
+                if source_ty_kind.is_floating_type()
+                    && target_ty_kind.is_enum_or_integral_type() =>
+            {
                 CastKind::FloatingToIntegral
             }
 
@@ -2684,6 +2742,10 @@ impl CTypeKind {
         matches!(*self, Self::Enum { .. })
     }
 
+    pub fn is_enum_or_integral_type(&self) -> bool {
+        self.is_integral_type() || self.is_enum()
+    }
+
     pub fn is_integral_type(&self) -> bool {
         self.is_unsigned_integral_type() || self.is_signed_integral_type()
     }