slightly cleaner, if more verbose, vtable handling in codegen backends

1 files changed, 9 insertions, 8 deletions

diff --git a/compiler/rustc_codegen_llvm/src/common.rs b/compiler/rustc_codegen_llvm/src/common.rs
index f83b3597438..fb4da9a5f33 100644
--- a/compiler/rustc_codegen_llvm/src/common.rs
+++ b/compiler/rustc_codegen_llvm/src/common.rs
@@ -240,13 +240,6 @@ impl<'ll, 'tcx> ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
             }
             Scalar::Ptr(ptr, _size) => {
                 let (alloc_id, offset) = ptr.into_parts();
-                // For vtables, get the underlying data allocation.
-                let alloc_id = match self.tcx.global_alloc(alloc_id) {
-                    GlobalAlloc::VTable(ty, trait_ref) => {
-                        self.tcx.vtable_allocation((ty, trait_ref))
-                    }
-                    _ => alloc_id,
-                };
                 let (base_addr, base_addr_space) = match self.tcx.global_alloc(alloc_id) {
                     GlobalAlloc::Memory(alloc) => {
                         let init = const_alloc_to_llvm(self, alloc);
@@ -264,7 +257,15 @@ impl<'ll, 'tcx> ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
                         self.get_fn_addr(fn_instance.polymorphize(self.tcx)),
                         self.data_layout().instruction_address_space,
                     ),
-                    GlobalAlloc::VTable(..) => bug!("vtables are already handled"),
+                    GlobalAlloc::VTable(ty, trait_ref) => {
+                        let alloc = self
+                            .tcx
+                            .global_alloc(self.tcx.vtable_allocation((ty, trait_ref)))
+                            .unwrap_memory();
+                        let init = const_alloc_to_llvm(self, alloc);
+                        let value = self.static_addr_of(init, alloc.inner().align, None);
+                        (value, AddressSpace::DATA)
+                    }
                     GlobalAlloc::Static(def_id) => {
                         assert!(self.tcx.is_static(def_id));
                         assert!(!self.tcx.is_thread_local_static(def_id));