CFI: Enable vtable shimming

Author: maurer

compiler/rustc_middle/src/ty/vtable.rs

@@ -94,7 +94,7 @@ pub(super) fn vtable_allocation_provider<'tcx>(
             VtblEntry::Vacant => continue,
             VtblEntry::Method(instance) => {
                 // Prepare the fn ptr we write into the vtable.
-                let instance = instance.polymorphize(tcx);
+                let instance = instance.cfi_shim(tcx, invoke_trait).polymorphize(tcx);
                 let fn_alloc_id = tcx.reserve_and_set_fn_alloc(instance);
                 let fn_ptr = Pointer::from(fn_alloc_id);
                 Scalar::from_pointer(fn_ptr, &tcx)

compiler/rustc_monomorphize/src/collector.rs

@@ -1213,9 +1213,8 @@ fn create_mono_items_for_vtable_methods<'tcx>(
                         // all super trait items already covered, so skip them.
                         None
                     }
-                    VtblEntry::Method(instance) => {
-                        Some(*instance).filter(|instance| should_codegen_locally(tcx, instance))
-                    }
+                    VtblEntry::Method(instance) => Some(instance.cfi_shim(tcx, invoke_trait))
+                        .filter(|instance| should_codegen_locally(tcx, instance)),
                 })
                 .map(|item| create_fn_mono_item(tcx, item, source));
             output.extend(methods);

tests/ui/sanitizer/cfi-alt-receiver.rs

@@ -0,0 +1,23 @@
+// Check alternate receivers work
+
+//@ needs-sanitizer-cfi
+//@ compile-flags: --crate-type=bin -Cprefer-dynamic=off -Clto -Zsanitizer=cfi
+//@ compile-flags: -C codegen-units=1 -C opt-level=0
+//@ run-pass
+
+use std::sync::Arc;
+
+trait Fooable {
+    fn foo(self: Arc<Self>);
+}
+
+struct Bar;
+
+impl Fooable for Bar {
+    fn foo(self: Arc<Self>) {}
+}
+
+fn main() {
+    let bar: Arc<dyn Fooable> = Arc::new(Bar);
+    bar.foo();
+}