Move mir::Field → abi::FieldIdx

The first PR for https://github.com/rust-lang/compiler-team/issues/606

This is just the move-and-rename, because it's plenty big-and-bitrotty already.  Future PRs will start using `FieldIdx` more broadly, and concomitantly removing `FieldIdx::new`s.

src/abi/mod.rs

@@ -327,7 +327,7 @@ pub(crate) fn codegen_fn_prelude<'tcx>(fx: &mut FunctionCx<'_, '_, 'tcx>, start_
             ArgKind::Spread(params) => {
                 for (i, param) in params.into_iter().enumerate() {
                     if let Some(param) = param {
-                        place.place_field(fx, mir::Field::new(i)).write_cvalue(fx, param);
+                        place.place_field(fx, FieldIdx::new(i)).write_cvalue(fx, param);
                     }
                 }
             }
@@ -460,7 +460,7 @@ pub(crate) fn codegen_terminator_call<'tcx>(
         args.push(self_arg);
         for i in 0..tupled_arguments.len() {
             args.push(CallArgument {
-                value: pack_arg.value.value_field(fx, mir::Field::new(i)),
+                value: pack_arg.value.value_field(fx, FieldIdx::new(i)),
                 is_owned: pack_arg.is_owned,
             });
         }

src/base.rs

@@ -797,7 +797,7 @@ fn codegen_stmt<'tcx>(
                             let index = fx.bcx.ins().iconst(fx.pointer_type, field_index as i64);
                             variant_dest.place_index(fx, index)
                         } else {
-                            variant_dest.place_field(fx, mir::Field::new(field_index))
+                            variant_dest.place_field(fx, FieldIdx::new(field_index))
                         };
                         to.write_cvalue(fx, operand);
                     }

src/discriminant.rs

@@ -26,7 +26,7 @@ pub(crate) fn codegen_set_discriminant<'tcx>(
             tag_encoding: TagEncoding::Direct,
             variants: _,
         } => {
-            let ptr = place.place_field(fx, mir::Field::new(tag_field));
+            let ptr = place.place_field(fx, FieldIdx::new(tag_field));
             let to = layout.ty.discriminant_for_variant(fx.tcx, variant_index).unwrap().val;
             let to = if ptr.layout().abi.is_signed() {
                 ty::ScalarInt::try_from_int(
@@ -47,7 +47,7 @@ pub(crate) fn codegen_set_discriminant<'tcx>(
             variants: _,
         } => {
             if variant_index != untagged_variant {
-                let niche = place.place_field(fx, mir::Field::new(tag_field));
+                let niche = place.place_field(fx, FieldIdx::new(tag_field));
                 let niche_type = fx.clif_type(niche.layout().ty).unwrap();
                 let niche_value = variant_index.as_u32() - niche_variants.start().as_u32();
                 let niche_value = (niche_value as u128).wrapping_add(niche_start);
@@ -107,7 +107,7 @@ pub(crate) fn codegen_get_discriminant<'tcx>(
     let cast_to = fx.clif_type(dest_layout.ty).unwrap();
 
     // Read the tag/niche-encoded discriminant from memory.
-    let tag = value.value_field(fx, mir::Field::new(tag_field));
+    let tag = value.value_field(fx, FieldIdx::new(tag_field));
     let tag = tag.load_scalar(fx);
 
     // Decode the discriminant (specifically if it's niche-encoded).

src/intrinsics/llvm_x86.rs

@@ -179,8 +179,8 @@ fn llvm_add_sub<'tcx>(
 
     // c + carry -> c + first intermediate carry or borrow respectively
     let int0 = crate::num::codegen_checked_int_binop(fx, bin_op, a, b);
-    let c = int0.value_field(fx, mir::Field::new(0));
+    let c = int0.value_field(fx, FieldIdx::new(0));
-    let cb0 = int0.value_field(fx, mir::Field::new(1)).load_scalar(fx);
+    let cb0 = int0.value_field(fx, FieldIdx::new(1)).load_scalar(fx);
 
     // c + carry -> c + second intermediate carry or borrow respectively
     let cb_in_as_u64 = fx.bcx.ins().uextend(types::I64, cb_in);

src/intrinsics/simd.rs

@@ -253,7 +253,7 @@ pub(super) fn codegen_simd_intrinsic_call<'tcx>(
             }
 
             ret.write_cvalue(fx, base);
-            let ret_lane = ret.place_field(fx, mir::Field::new(idx.try_into().unwrap()));
+            let ret_lane = ret.place_field(fx, FieldIdx::new(idx.try_into().unwrap()));
             ret_lane.write_cvalue(fx, val);
         }
 

src/lib.rs

@@ -86,7 +86,7 @@ mod prelude {
         self, FloatTy, Instance, InstanceDef, IntTy, ParamEnv, Ty, TyCtxt, TypeAndMut,
         TypeFoldable, TypeVisitableExt, UintTy,
     };
-    pub(crate) use rustc_target::abi::{Abi, Scalar, Size, VariantIdx, FIRST_VARIANT};
+    pub(crate) use rustc_target::abi::{Abi, FieldIdx, Scalar, Size, VariantIdx, FIRST_VARIANT};
 
     pub(crate) use rustc_data_structures::fx::FxHashMap;
 

src/unsize.rs

@@ -147,8 +147,8 @@ pub(crate) fn coerce_unsized_into<'tcx>(
             assert_eq!(def_a, def_b);
 
             for i in 0..def_a.variant(FIRST_VARIANT).fields.len() {
-                let src_f = src.value_field(fx, mir::Field::new(i));
+                let src_f = src.value_field(fx, FieldIdx::new(i));
-                let dst_f = dst.place_field(fx, mir::Field::new(i));
+                let dst_f = dst.place_field(fx, FieldIdx::new(i));
 
                 if dst_f.layout().is_zst() {
                     continue;

src/value_and_place.rs

@@ -10,7 +10,7 @@ fn codegen_field<'tcx>(
     base: Pointer,
     extra: Option<Value>,
     layout: TyAndLayout<'tcx>,
-    field: mir::Field,
+    field: FieldIdx,
 ) -> (Pointer, TyAndLayout<'tcx>) {
     let field_offset = layout.fields.offset(field.index());
     let field_layout = layout.field(&*fx, field.index());
@@ -210,7 +210,7 @@ impl<'tcx> CValue<'tcx> {
     pub(crate) fn value_field(
         self,
         fx: &mut FunctionCx<'_, '_, 'tcx>,
-        field: mir::Field,
+        field: FieldIdx,
     ) -> CValue<'tcx> {
         let layout = self.1;
         match self.0 {
@@ -687,7 +687,7 @@ impl<'tcx> CPlace<'tcx> {
     pub(crate) fn place_field(
         self,
         fx: &mut FunctionCx<'_, '_, 'tcx>,
-        field: mir::Field,
+        field: FieldIdx,
     ) -> CPlace<'tcx> {
         let layout = self.layout();
 

src/vtable.rs

@@ -50,7 +50,7 @@ pub(crate) fn get_ptr_and_method_ref<'tcx>(
         if let Abi::Scalar(_) = arg.layout().abi {
             'descend_newtypes: while !arg.layout().ty.is_unsafe_ptr() && !arg.layout().ty.is_ref() {
                 for i in 0..arg.layout().fields.count() {
-                    let field = arg.value_field(fx, mir::Field::new(i));
+                    let field = arg.value_field(fx, FieldIdx::new(i));
                     if !field.layout().is_zst() {
                         // we found the one non-zero-sized field that is allowed
                         // now find *its* non-zero-sized field, or stop if it's a
@@ -68,9 +68,9 @@ pub(crate) fn get_ptr_and_method_ref<'tcx>(
             if ty.is_dyn_star() {
                 let inner_layout = fx.layout_of(arg.layout().ty.builtin_deref(true).unwrap().ty);
                 let dyn_star = CPlace::for_ptr(Pointer::new(arg.load_scalar(fx)), inner_layout);
-                let ptr = dyn_star.place_field(fx, mir::Field::new(0)).to_ptr();
+                let ptr = dyn_star.place_field(fx, FieldIdx::new(0)).to_ptr();
                 let vtable =
-                    dyn_star.place_field(fx, mir::Field::new(1)).to_cvalue(fx).load_scalar(fx);
+                    dyn_star.place_field(fx, FieldIdx::new(1)).to_cvalue(fx).load_scalar(fx);
                 break 'block (ptr, vtable);
             }
         }