Rollup merge of #63464 - Mark-Simulacrum:deref-instance, r=eddyb

Copy ty::Instance instead of passing by reference

ty::Instance is small and Copy, we should not be adding additional
indirection.

Fixes #63409.

r? @eddyb

Author: Mark-Simulacrum

src/librustc/ty/layout.rs

@@ -2518,7 +2518,7 @@ where
         + HasTyCtxt<'tcx>
         + HasParamEnv<'tcx>,
 {
-    fn of_instance(cx: &C, instance: &ty::Instance<'tcx>) -> Self;
+    fn of_instance(cx: &C, instance: ty::Instance<'tcx>) -> Self;
     fn new(cx: &C, sig: ty::FnSig<'tcx>, extra_args: &[Ty<'tcx>]) -> Self;
     fn new_vtable(cx: &C, sig: ty::FnSig<'tcx>, extra_args: &[Ty<'tcx>]) -> Self;
     fn new_internal(
@@ -2538,7 +2538,7 @@ where
         + HasTyCtxt<'tcx>
         + HasParamEnv<'tcx>,
 {
-    fn of_instance(cx: &C, instance: &ty::Instance<'tcx>) -> Self {
+    fn of_instance(cx: &C, instance: ty::Instance<'tcx>) -> Self {
         let sig = instance.fn_sig(cx.tcx());
         let sig = cx
             .tcx()

src/librustc_codegen_ssa/mir/block.rs

@@ -337,7 +337,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             }
             _ => {
                 (bx.get_fn(drop_fn),
-                 FnType::of_instance(&bx, &drop_fn))
+                 FnType::of_instance(&bx, drop_fn))
             }
         };
         helper.do_call(self, &mut bx, fn_ty, drop_fn, args,
@@ -435,7 +435,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         // Obtain the panic entry point.
         let def_id = common::langcall(bx.tcx(), Some(span), "", lang_item);
         let instance = ty::Instance::mono(bx.tcx(), def_id);
-        let fn_ty = FnType::of_instance(&bx, &instance);
+        let fn_ty = FnType::of_instance(&bx, instance);
         let llfn = bx.get_fn(instance);
 
         // Codegen the actual panic invoke/call.
@@ -552,7 +552,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 let def_id =
                     common::langcall(bx.tcx(), Some(span), "", lang_items::PanicFnLangItem);
                 let instance = ty::Instance::mono(bx.tcx(), def_id);
-                let fn_ty = FnType::of_instance(&bx, &instance);
+                let fn_ty = FnType::of_instance(&bx, instance);
                 let llfn = bx.get_fn(instance);
 
                 // Codegen the actual panic invoke/call.

src/librustc_mir/interpret/snapshot.rs

@@ -304,7 +304,7 @@ impl_stable_hash_for!(enum crate::interpret::eval_context::StackPopCleanup {
 
 #[derive(Eq, PartialEq)]
 struct FrameSnapshot<'a, 'tcx> {
-    instance: &'a ty::Instance<'tcx>,
+    instance: ty::Instance<'tcx>,
     span: Span,
     return_to_block: &'a StackPopCleanup,
     return_place: Option<Place<(), AllocIdSnapshot<'a>>>,
@@ -344,7 +344,7 @@ impl<'a, 'mir, 'tcx, Ctx> Snapshot<'a, Ctx> for &'a Frame<'mir, 'tcx>
         } = self;
 
         FrameSnapshot {
-            instance,
+            instance: *instance,
             span: *span,
             return_to_block,
             block,