Add HasVtable::has_vtable_ptr for querying if a type has its own vtable pointer

Author: fitzgen

src/ir/analysis/has_vtable.rs

@@ -242,4 +242,8 @@ impl<'ctx> From<HasVtableAnalysis<'ctx>> for HashMap<ItemId, HasVtableResult> {
 pub trait HasVtable {
     /// Return `true` if this thing has vtable, `false` otherwise.
     fn has_vtable(&self, ctx: &BindgenContext) -> bool;
+
+    /// Return `true` if this thing has an actual vtable pointer in itself, as
+    /// opposed to transitively in a base member.
+    fn has_vtable_ptr(&self, ctx: &BindgenContext) -> bool;
 }

src/ir/comp.rs

@@ -1012,7 +1012,7 @@ impl CompInfo {
 
     /// Is this compound type unsized?
     pub fn is_unsized(&self, ctx: &BindgenContext, id: TypeId) -> bool {
-        !ctx.lookup_has_vtable(id) && self.fields().is_empty() &&
+        !id.has_vtable(ctx) && self.fields().is_empty() &&
             self.base_members.iter().all(|base| {
                 ctx.resolve_type(base.ty).canonical_type(ctx).is_unsized(
                     ctx,

src/ir/context.rs

@@ -1267,15 +1267,20 @@ impl BindgenContext {
     }
 
     /// Look up whether the item with `id` has vtable or not.
-    pub fn lookup_has_vtable(&self, id: TypeId) -> bool {
+    pub fn lookup_has_vtable(&self, id: TypeId) -> HasVtableResult {
         assert!(
             self.in_codegen_phase(),
             "We only compute vtables when we enter codegen"
         );
 
         // Look up the computed value for whether the item with `id` has a
         // vtable or not.
-        self.have_vtable.as_ref().unwrap().contains_key(&id.into())
+        self.have_vtable
+            .as_ref()
+            .unwrap()
+            .get(&id.into())
+            .cloned()
+            .unwrap_or(HasVtableResult::No)
     }
 
     /// Compute whether the type has a destructor.

src/ir/item.rs

@@ -1,6 +1,6 @@
 //! Bindgen's core intermediate representation type.
 
-use super::analysis::HasVtable;
+use super::analysis::{HasVtable, HasVtableResult};
 use super::annotations::Annotations;
 use super::comment;
 use super::comp::MethodKind;
@@ -1001,15 +1001,29 @@ where
     fn has_vtable(&self, ctx: &BindgenContext) -> bool {
         let id: ItemId = (*self).into();
         id.as_type_id(ctx)
-            .map_or(false, |id| ctx.lookup_has_vtable(id))
+            .map_or(false, |id| match ctx.lookup_has_vtable(id) {
+                HasVtableResult::No => false,
+                _ => true,
+            })
+    }
+
+    fn has_vtable_ptr(&self, ctx: &BindgenContext) -> bool {
+        let id: ItemId = (*self).into();
+        id.as_type_id(ctx)
+            .map_or(false, |id| match ctx.lookup_has_vtable(id) {
+                HasVtableResult::SelfHasVtable => true,
+                _ => false,
+            })
     }
 }
 
 impl HasVtable for Item {
     fn has_vtable(&self, ctx: &BindgenContext) -> bool {
-        self.id()
-            .as_type_id(ctx)
-            .map_or(false, |id| ctx.lookup_has_vtable(id))
+        self.id().has_vtable(ctx)
+    }
+
+    fn has_vtable_ptr(&self, ctx: &BindgenContext) -> bool {
+        self.id().has_vtable_ptr(ctx)
     }
 }