Make dyn-trait-method work

Author: compiler-errors

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -907,7 +907,30 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                         llargs.push(data_ptr);
                         continue;
                     }
-                    _ => span_bug!(span, "can't codegen a virtual call on {:#?}", op),
+                    Immediate(_) => {
+                        let ty::Ref(_, ty, _) = op.layout.ty.kind() else {
+                            span_bug!(span, "can't codegen a virtual call on {:#?}", op);
+                        };
+                        if !ty.is_dyn_star() {
+                            span_bug!(span, "can't codegen a virtual call on {:#?}", op);
+                        }
+                        // FIXME(dyn-star): Make sure this is done on a &dyn* receiver
+                        let place = op.deref(bx.cx());
+                        let data_ptr = place.project_field(&mut bx, 0);
+                        let meta_ptr = place.project_field(&mut bx, 1);
+                        let meta = bx.load_operand(meta_ptr);
+                        llfn = Some(meth::VirtualIndex::from_index(idx).get_fn(
+                            &mut bx,
+                            meta.immediate(),
+                            op.layout.ty,
+                            &fn_abi,
+                        ));
+                        llargs.push(data_ptr.llval);
+                        continue;
+                    }
+                    _ => {
+                        span_bug!(span, "can't codegen a virtual call on {:#?}", op);
+                    }
                 }
             }
 

compiler/rustc_middle/src/ty/layout.rs

@@ -626,7 +626,7 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
             }
 
             ty::Dynamic(_, _, ty::DynStar) => {
-                let mut pointer = scalar_unit(Pointer);
+                let mut pointer = scalar_unit(Int(dl.ptr_sized_integer(), false));
                 pointer.valid_range_mut().start = 1;
                 let mut vtable = scalar_unit(Pointer);
                 vtable.valid_range_mut().start = 1;
@@ -2544,8 +2544,21 @@ where
                     }
                 }
 
-                // dyn* (both fields are usize-sized)
-                ty::Dynamic(_, _, ty::DynStar) => TyMaybeWithLayout::Ty(tcx.types.usize),
+                ty::Dynamic(_, _, ty::DynStar) => {
+                    if i == 0 {
+                        TyMaybeWithLayout::Ty(tcx.types.usize)
+                    } else if i == 1 {
+                        // FIXME(dyn-star) same FIXME as above applies here too
+                        TyMaybeWithLayout::Ty(
+                            tcx.mk_imm_ref(
+                                tcx.lifetimes.re_static,
+                                tcx.mk_array(tcx.types.usize, 3),
+                            ),
+                        )
+                    } else {
+                        bug!("no field {i} on dyn*")
+                    }
+                }
 
                 ty::Projection(_)
                 | ty::Bound(..)