Box `CastTarget` within `PassMode`.

Because `PassMode::Cast` is by far the largest variant, but is
relatively rare.

This requires making `PassMode` not impl `Copy`, and `Clone` is no
longer necessary. This causes lots of sigil adjusting, but nothing very
notable.

1 files changed, 2 insertions, 2 deletions

diff --git a/compiler/rustc_codegen_gcc/src/abi.rs b/compiler/rustc_codegen_gcc/src/abi.rs
index 0ed3e1fbe93..9b55db6a547 100644
--- a/compiler/rustc_codegen_gcc/src/abi.rs
+++ b/compiler/rustc_codegen_gcc/src/abi.rs
@@ -133,7 +133,7 @@ impl<'gcc, 'tcx> FnAbiGccExt<'gcc, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
             match self.ret.mode {
                 PassMode::Ignore => cx.type_void(),
                 PassMode::Direct(_) | PassMode::Pair(..) => self.ret.layout.immediate_gcc_type(cx),
-                PassMode::Cast(cast) => cast.gcc_type(cx),
+                PassMode::Cast(ref cast) => cast.gcc_type(cx),
                 PassMode::Indirect { .. } => {
                     argument_tys.push(cx.type_ptr_to(self.ret.memory_ty(cx)));
                     cx.type_void()
@@ -157,7 +157,7 @@ impl<'gcc, 'tcx> FnAbiGccExt<'gcc, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
                 PassMode::Indirect { extra_attrs: Some(_), .. } => {
                     unimplemented!();
                 }
-                PassMode::Cast(cast) => cast.gcc_type(cx),
+                PassMode::Cast(ref cast) => cast.gcc_type(cx),
                 PassMode::Indirect { extra_attrs: None, on_stack: true, .. } => {
                     on_stack_param_indices.insert(argument_tys.len());
                     arg.memory_ty(cx)