Move vcall_visibility_metadata optimization hint out of a debuginfo generation method

compiler/rustc_codegen_llvm/src/context.rs

@@ -3,6 +3,7 @@ use crate::back::write::to_llvm_code_model;
 use crate::callee::get_fn;
 use crate::coverageinfo;
 use crate::debuginfo;
+use crate::debuginfo::metadata::apply_vcall_visibility_metadata;
 use crate::llvm;
 use crate::llvm_util;
 use crate::type_::Type;
@@ -522,6 +523,15 @@ impl<'ll, 'tcx> MiscMethods<'tcx> for CodegenCx<'ll, 'tcx> {
         &self.vtables
     }
 
+    fn apply_vcall_visibility_metadata(
+        &self,
+        ty: Ty<'tcx>,
+        poly_trait_ref: Option<ty::PolyExistentialTraitRef<'tcx>>,
+        vtable: &'ll Value,
+    ) {
+        apply_vcall_visibility_metadata(self, ty, poly_trait_ref, vtable);
+    }
+
     fn get_fn(&self, instance: Instance<'tcx>) -> &'ll Value {
         get_fn(self, instance)
     }

compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs

@@ -1449,12 +1449,18 @@ fn build_vtable_type_di_node<'ll, 'tcx>(
     .di_node
 }
 
-fn vcall_visibility_metadata<'ll, 'tcx>(
+pub(crate) fn apply_vcall_visibility_metadata<'ll, 'tcx>(
     cx: &CodegenCx<'ll, 'tcx>,
     ty: Ty<'tcx>,
     trait_ref: Option<PolyExistentialTraitRef<'tcx>>,
     vtable: &'ll Value,
 ) {
+    // FIXME(flip1995): The virtual function elimination optimization only works with full LTO in
+    // LLVM at the moment.
+    if !cx.sess().opts.unstable_opts.virtual_function_elimination || cx.sess().lto() != Lto::Fat {
+        return;
+    }
+
     enum VCallVisibility {
         Public = 0,
         LinkageUnit = 1,
@@ -1531,12 +1537,6 @@ pub fn create_vtable_di_node<'ll, 'tcx>(
     poly_trait_ref: Option<ty::PolyExistentialTraitRef<'tcx>>,
     vtable: &'ll Value,
 ) {
-    // FIXME(flip1995): The virtual function elimination optimization only works with full LTO in
-    // LLVM at the moment.
-    if cx.sess().opts.unstable_opts.virtual_function_elimination && cx.sess().lto() == Lto::Fat {
-        vcall_visibility_metadata(cx, ty, poly_trait_ref, vtable);
-    }
-
     if cx.dbg_cx.is_none() {
         return;
     }

compiler/rustc_codegen_ssa/src/meth.rs

@@ -133,6 +133,7 @@ pub fn get_vtable<'tcx, Cx: CodegenMethods<'tcx>>(
     let align = cx.data_layout().pointer_align.abi;
     let vtable = cx.static_addr_of(vtable_const, align, Some("vtable"));
 
+    cx.apply_vcall_visibility_metadata(ty, trait_ref, vtable);
     cx.create_vtable_debuginfo(ty, trait_ref, vtable);
     cx.vtables().borrow_mut().insert((ty, trait_ref), vtable);
     vtable

compiler/rustc_codegen_ssa/src/traits/misc.rs

@@ -9,6 +9,13 @@ pub trait MiscMethods<'tcx>: BackendTypes {
     fn vtables(
         &self,
     ) -> &RefCell<FxHashMap<(Ty<'tcx>, Option<ty::PolyExistentialTraitRef<'tcx>>), Self::Value>>;
+    fn apply_vcall_visibility_metadata(
+        &self,
+        _ty: Ty<'tcx>,
+        _poly_trait_ref: Option<ty::PolyExistentialTraitRef<'tcx>>,
+        _vtable: Self::Value,
+    ) {
+    }
     fn check_overflow(&self) -> bool;
     fn get_fn(&self, instance: Instance<'tcx>) -> Self::Function;
     fn get_fn_addr(&self, instance: Instance<'tcx>) -> Self::Value;