2 use rustc_hir::def_id::DefId;
3 use rustc_hir::lang_items::LangItem;
4 use rustc_middle::mir::*;
5 use rustc_middle::ty::query::Providers;
6 use rustc_middle::ty::subst::{InternalSubsts, Subst};
7 use rustc_middle::ty::{self, EarlyBinder, Ty, TyCtxt};
8 use rustc_target::abi::VariantIdx;
10 use rustc_index::vec::{Idx, IndexVec};
13 use rustc_target::spec::abi::Abi;
18 use crate::util::expand_aggregate;
20 abort_unwinding_calls, add_call_guards, add_moves_for_packed_drops, marker, pass_manager as pm,
21 remove_noop_landing_pads, simplify,
23 use rustc_middle::mir::patch::MirPatch;
24 use rustc_mir_dataflow::elaborate_drops::{self, DropElaborator, DropFlagMode, DropStyle};
26 pub fn provide(providers: &mut Providers) {
27 providers.mir_shims = make_shim;
30 fn make_shim<'tcx>(tcx: TyCtxt<'tcx>, instance: ty::InstanceDef<'tcx>) -> Body<'tcx> {
31 debug!("make_shim({:?})", instance);
33 let mut result = match instance {
34 ty::InstanceDef::Item(..) => bug!("item {:?} passed to make_shim", instance),
35 ty::InstanceDef::VtableShim(def_id) => {
36 build_call_shim(tcx, instance, Some(Adjustment::Deref), CallKind::Direct(def_id))
38 ty::InstanceDef::FnPtrShim(def_id, ty) => {
39 let trait_ = tcx.trait_of_item(def_id).unwrap();
40 let adjustment = match tcx.fn_trait_kind_from_lang_item(trait_) {
41 Some(ty::ClosureKind::FnOnce) => Adjustment::Identity,
42 Some(ty::ClosureKind::FnMut | ty::ClosureKind::Fn) => Adjustment::Deref,
43 None => bug!("fn pointer {:?} is not an fn", ty),
46 build_call_shim(tcx, instance, Some(adjustment), CallKind::Indirect(ty))
48 // We are generating a call back to our def-id, which the
49 // codegen backend knows to turn to an actual call, be it
50 // a virtual call, or a direct call to a function for which
51 // indirect calls must be codegen'd differently than direct ones
52 // (such as `#[track_caller]`).
53 ty::InstanceDef::ReifyShim(def_id) => {
54 build_call_shim(tcx, instance, None, CallKind::Direct(def_id))
56 ty::InstanceDef::ClosureOnceShim { call_once: _, track_caller: _ } => {
57 let fn_mut = tcx.require_lang_item(LangItem::FnMut, None);
59 .associated_items(fn_mut)
60 .in_definition_order()
61 .find(|it| it.kind == ty::AssocKind::Fn)
65 build_call_shim(tcx, instance, Some(Adjustment::RefMut), CallKind::Direct(call_mut))
68 ty::InstanceDef::DropGlue(def_id, ty) => {
69 // FIXME(#91576): Drop shims for generators aren't subject to the MIR passes at the end
70 // of this function. Is this intentional?
71 if let Some(ty::Generator(gen_def_id, substs, _)) = ty.map(Ty::kind) {
72 let body = tcx.optimized_mir(*gen_def_id).generator_drop().unwrap();
73 let body = EarlyBinder(body.clone()).subst(tcx, substs);
74 debug!("make_shim({:?}) = {:?}", instance, body);
78 build_drop_shim(tcx, def_id, ty)
80 ty::InstanceDef::CloneShim(def_id, ty) => build_clone_shim(tcx, def_id, ty),
81 ty::InstanceDef::Virtual(..) => {
82 bug!("InstanceDef::Virtual ({:?}) is for direct calls only", instance)
84 ty::InstanceDef::Intrinsic(_) => {
85 bug!("creating shims from intrinsics ({:?}) is unsupported", instance)
88 debug!("make_shim({:?}) = untransformed {:?}", instance, result);
94 &add_moves_for_packed_drops::AddMovesForPackedDrops,
95 &remove_noop_landing_pads::RemoveNoopLandingPads,
96 &simplify::SimplifyCfg::new("make_shim"),
97 &add_call_guards::CriticalCallEdges,
98 &abort_unwinding_calls::AbortUnwindingCalls,
99 &marker::PhaseChange(MirPhase::Const),
103 debug!("make_shim({:?}) = {:?}", instance, result);
108 #[derive(Copy, Clone, Debug, PartialEq)]
110 /// Pass the receiver as-is.
113 /// We get passed `&[mut] self` and call the target with `*self`.
115 /// This either copies `self` (if `Self: Copy`, eg. for function items), or moves out of it
116 /// (for `VtableShim`, which effectively is passed `&own Self`).
119 /// We get passed `self: Self` and call the target with `&mut self`.
121 /// In this case we need to ensure that the `Self` is dropped after the call, as the callee
122 /// won't do it for us.
126 #[derive(Copy, Clone, Debug, PartialEq)]
127 enum CallKind<'tcx> {
128 /// Call the `FnPtr` that was passed as the receiver.
131 /// Call a known `FnDef`.
135 fn local_decls_for_sig<'tcx>(
136 sig: &ty::FnSig<'tcx>,
138 ) -> IndexVec<Local, LocalDecl<'tcx>> {
139 iter::once(LocalDecl::new(sig.output(), span))
140 .chain(sig.inputs().iter().map(|ity| LocalDecl::new(*ity, span).immutable()))
144 fn build_drop_shim<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, ty: Option<Ty<'tcx>>) -> Body<'tcx> {
145 debug!("build_drop_shim(def_id={:?}, ty={:?})", def_id, ty);
147 assert!(!matches!(ty, Some(ty) if ty.is_generator()));
149 let substs = if let Some(ty) = ty {
150 tcx.intern_substs(&[ty.into()])
152 InternalSubsts::identity_for_item(tcx, def_id)
154 let sig = tcx.bound_fn_sig(def_id).subst(tcx, substs);
155 let sig = tcx.erase_late_bound_regions(sig);
156 let span = tcx.def_span(def_id);
158 let source_info = SourceInfo::outermost(span);
160 let return_block = BasicBlock::new(1);
161 let mut blocks = IndexVec::with_capacity(2);
162 let block = |blocks: &mut IndexVec<_, _>, kind| {
163 blocks.push(BasicBlockData {
165 terminator: Some(Terminator { source_info, kind }),
169 block(&mut blocks, TerminatorKind::Goto { target: return_block });
170 block(&mut blocks, TerminatorKind::Return);
172 let source = MirSource::from_instance(ty::InstanceDef::DropGlue(def_id, ty));
174 new_body(source, blocks, local_decls_for_sig(&sig, span), sig.inputs().len(), span);
177 // The first argument (index 0), but add 1 for the return value.
178 let dropee_ptr = Place::from(Local::new(1 + 0));
179 if tcx.sess.opts.unstable_opts.mir_emit_retag {
180 // Function arguments should be retagged, and we make this one raw.
181 body.basic_blocks_mut()[START_BLOCK].statements.insert(
185 kind: StatementKind::Retag(RetagKind::Raw, Box::new(dropee_ptr)),
190 let param_env = tcx.param_env_reveal_all_normalized(def_id);
192 DropShimElaborator { body: &body, patch: MirPatch::new(&body), tcx, param_env };
193 let dropee = tcx.mk_place_deref(dropee_ptr);
194 let resume_block = elaborator.patch.resume_block();
195 elaborate_drops::elaborate_drop(
201 elaborate_drops::Unwind::To(resume_block),
206 patch.apply(&mut body);
213 source: MirSource<'tcx>,
214 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
215 local_decls: IndexVec<Local, LocalDecl<'tcx>>,
222 IndexVec::from_elem_n(
227 inlined_parent_scope: None,
228 local_data: ClearCrossCrate::Clear,
238 // FIXME(compiler-errors): is this correct?
243 pub struct DropShimElaborator<'a, 'tcx> {
244 pub body: &'a Body<'tcx>,
245 pub patch: MirPatch<'tcx>,
246 pub tcx: TyCtxt<'tcx>,
247 pub param_env: ty::ParamEnv<'tcx>,
250 impl fmt::Debug for DropShimElaborator<'_, '_> {
251 fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
256 impl<'a, 'tcx> DropElaborator<'a, 'tcx> for DropShimElaborator<'a, 'tcx> {
259 fn patch(&mut self) -> &mut MirPatch<'tcx> {
262 fn body(&self) -> &'a Body<'tcx> {
265 fn tcx(&self) -> TyCtxt<'tcx> {
268 fn param_env(&self) -> ty::ParamEnv<'tcx> {
272 fn drop_style(&self, _path: Self::Path, mode: DropFlagMode) -> DropStyle {
274 DropFlagMode::Shallow => {
275 // Drops for the contained fields are "shallow" and "static" - they will simply call
276 // the field's own drop glue.
279 DropFlagMode::Deep => {
280 // The top-level drop is "deep" and "open" - it will be elaborated to a drop ladder
281 // dropping each field contained in the value.
287 fn get_drop_flag(&mut self, _path: Self::Path) -> Option<Operand<'tcx>> {
291 fn clear_drop_flag(&mut self, _location: Location, _path: Self::Path, _mode: DropFlagMode) {}
293 fn field_subpath(&self, _path: Self::Path, _field: Field) -> Option<Self::Path> {
296 fn deref_subpath(&self, _path: Self::Path) -> Option<Self::Path> {
299 fn downcast_subpath(&self, _path: Self::Path, _variant: VariantIdx) -> Option<Self::Path> {
302 fn array_subpath(&self, _path: Self::Path, _index: u64, _size: u64) -> Option<Self::Path> {
307 /// Builds a `Clone::clone` shim for `self_ty`. Here, `def_id` is `Clone::clone`.
308 fn build_clone_shim<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, self_ty: Ty<'tcx>) -> Body<'tcx> {
309 debug!("build_clone_shim(def_id={:?})", def_id);
311 let param_env = tcx.param_env(def_id);
313 let mut builder = CloneShimBuilder::new(tcx, def_id, self_ty);
314 let is_copy = self_ty.is_copy_modulo_regions(tcx.at(builder.span), param_env);
316 let dest = Place::return_place();
317 let src = tcx.mk_place_deref(Place::from(Local::new(1 + 0)));
319 match self_ty.kind() {
320 _ if is_copy => builder.copy_shim(),
321 ty::Closure(_, substs) => {
322 builder.tuple_like_shim(dest, src, substs.as_closure().upvar_tys())
324 ty::Tuple(..) => builder.tuple_like_shim(dest, src, self_ty.tuple_fields()),
325 _ => bug!("clone shim for `{:?}` which is not `Copy` and is not an aggregate", self_ty),
331 struct CloneShimBuilder<'tcx> {
334 local_decls: IndexVec<Local, LocalDecl<'tcx>>,
335 blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
337 sig: ty::FnSig<'tcx>,
340 impl<'tcx> CloneShimBuilder<'tcx> {
341 fn new(tcx: TyCtxt<'tcx>, def_id: DefId, self_ty: Ty<'tcx>) -> Self {
342 // we must subst the self_ty because it's
343 // otherwise going to be TySelf and we can't index
344 // or access fields of a Place of type TySelf.
345 let substs = tcx.mk_substs_trait(self_ty, &[]);
346 let sig = tcx.bound_fn_sig(def_id).subst(tcx, substs);
347 let sig = tcx.erase_late_bound_regions(sig);
348 let span = tcx.def_span(def_id);
353 local_decls: local_decls_for_sig(&sig, span),
354 blocks: IndexVec::new(),
360 fn into_mir(self) -> Body<'tcx> {
361 let source = MirSource::from_instance(ty::InstanceDef::CloneShim(
363 self.sig.inputs_and_output[0],
365 new_body(source, self.blocks, self.local_decls, self.sig.inputs().len(), self.span)
368 fn source_info(&self) -> SourceInfo {
369 SourceInfo::outermost(self.span)
374 statements: Vec<Statement<'tcx>>,
375 kind: TerminatorKind<'tcx>,
378 let source_info = self.source_info();
379 self.blocks.push(BasicBlockData {
381 terminator: Some(Terminator { source_info, kind }),
386 /// Gives the index of an upcoming BasicBlock, with an offset.
387 /// offset=0 will give you the index of the next BasicBlock,
388 /// offset=1 will give the index of the next-to-next block,
389 /// offset=-1 will give you the index of the last-created block
390 fn block_index_offset(&mut self, offset: usize) -> BasicBlock {
391 BasicBlock::new(self.blocks.len() + offset)
394 fn make_statement(&self, kind: StatementKind<'tcx>) -> Statement<'tcx> {
395 Statement { source_info: self.source_info(), kind }
398 fn copy_shim(&mut self) {
399 let rcvr = self.tcx.mk_place_deref(Place::from(Local::new(1 + 0)));
400 let ret_statement = self.make_statement(StatementKind::Assign(Box::new((
401 Place::return_place(),
402 Rvalue::Use(Operand::Copy(rcvr)),
404 self.block(vec![ret_statement], TerminatorKind::Return, false);
407 fn make_place(&mut self, mutability: Mutability, ty: Ty<'tcx>) -> Place<'tcx> {
408 let span = self.span;
409 let mut local = LocalDecl::new(ty, span);
410 if mutability == Mutability::Not {
411 local = local.immutable();
413 Place::from(self.local_decls.push(local))
426 let substs = tcx.mk_substs_trait(ty, &[]);
428 // `func == Clone::clone(&ty) -> ty`
429 let func_ty = tcx.mk_fn_def(self.def_id, substs);
430 let func = Operand::Constant(Box::new(Constant {
433 literal: ConstantKind::zero_sized(func_ty),
436 let ref_loc = self.make_place(
438 tcx.mk_ref(tcx.lifetimes.re_erased, ty::TypeAndMut { ty, mutbl: hir::Mutability::Not }),
441 // `let ref_loc: &ty = &src;`
442 let statement = self.make_statement(StatementKind::Assign(Box::new((
444 Rvalue::Ref(tcx.lifetimes.re_erased, BorrowKind::Shared, src),
447 // `let loc = Clone::clone(ref_loc);`
450 TerminatorKind::Call {
452 args: vec![Operand::Move(ref_loc)],
455 cleanup: Some(cleanup),
463 fn tuple_like_shim<I>(&mut self, dest: Place<'tcx>, src: Place<'tcx>, tys: I)
465 I: IntoIterator<Item = Ty<'tcx>>,
467 let mut previous_field = None;
468 for (i, ity) in tys.into_iter().enumerate() {
469 let field = Field::new(i);
470 let src_field = self.tcx.mk_place_field(src, field, ity);
472 let dest_field = self.tcx.mk_place_field(dest, field, ity);
474 // #(2i + 1) is the cleanup block for the previous clone operation
475 let cleanup_block = self.block_index_offset(1);
476 // #(2i + 2) is the next cloning block
477 // (or the Return terminator if this is the last block)
478 let next_block = self.block_index_offset(2);
481 // `dest.i = Clone::clone(&src.i);`
482 // Goto #(2i + 2) if ok, #(2i + 1) if unwinding happens.
483 self.make_clone_call(dest_field, src_field, ity, next_block, cleanup_block);
485 // BB #(2i + 1) (cleanup)
486 if let Some((previous_field, previous_cleanup)) = previous_field.take() {
487 // Drop previous field and goto previous cleanup block.
490 TerminatorKind::Drop {
491 place: previous_field,
492 target: previous_cleanup,
498 // Nothing to drop, just resume.
499 self.block(vec![], TerminatorKind::Resume, true);
502 previous_field = Some((dest_field, cleanup_block));
505 self.block(vec![], TerminatorKind::Return, false);
509 /// Builds a "call" shim for `instance`. The shim calls the function specified by `call_kind`,
510 /// first adjusting its first argument according to `rcvr_adjustment`.
511 fn build_call_shim<'tcx>(
513 instance: ty::InstanceDef<'tcx>,
514 rcvr_adjustment: Option<Adjustment>,
515 call_kind: CallKind<'tcx>,
518 "build_call_shim(instance={:?}, rcvr_adjustment={:?}, call_kind={:?})",
519 instance, rcvr_adjustment, call_kind
522 // `FnPtrShim` contains the fn pointer type that a call shim is being built for - this is used
523 // to substitute into the signature of the shim. It is not necessary for users of this
524 // MIR body to perform further substitutions (see `InstanceDef::has_polymorphic_mir_body`).
525 let (sig_substs, untuple_args) = if let ty::InstanceDef::FnPtrShim(_, ty) = instance {
526 let sig = tcx.erase_late_bound_regions(ty.fn_sig(tcx));
528 let untuple_args = sig.inputs();
530 // Create substitutions for the `Self` and `Args` generic parameters of the shim body.
531 let arg_tup = tcx.mk_tup(untuple_args.iter());
532 let sig_substs = tcx.mk_substs_trait(ty, &[ty::subst::GenericArg::from(arg_tup)]);
534 (Some(sig_substs), Some(untuple_args))
539 let def_id = instance.def_id();
540 let sig = tcx.bound_fn_sig(def_id);
541 let sig = sig.map_bound(|sig| tcx.erase_late_bound_regions(sig));
543 assert_eq!(sig_substs.is_some(), !instance.has_polymorphic_mir_body());
545 if let Some(sig_substs) = sig_substs { sig.subst(tcx, sig_substs) } else { sig.0 };
547 if let CallKind::Indirect(fnty) = call_kind {
548 // `sig` determines our local decls, and thus the callee type in the `Call` terminator. This
549 // can only be an `FnDef` or `FnPtr`, but currently will be `Self` since the types come from
550 // the implemented `FnX` trait.
552 // Apply the opposite adjustment to the MIR input.
553 let mut inputs_and_output = sig.inputs_and_output.to_vec();
555 // Initial signature is `fn(&? Self, Args) -> Self::Output` where `Args` is a tuple of the
556 // fn arguments. `Self` may be passed via (im)mutable reference or by-value.
557 assert_eq!(inputs_and_output.len(), 3);
559 // `Self` is always the original fn type `ty`. The MIR call terminator is only defined for
560 // `FnDef` and `FnPtr` callees, not the `Self` type param.
561 let self_arg = &mut inputs_and_output[0];
562 *self_arg = match rcvr_adjustment.unwrap() {
563 Adjustment::Identity => fnty,
564 Adjustment::Deref => tcx.mk_imm_ptr(fnty),
565 Adjustment::RefMut => tcx.mk_mut_ptr(fnty),
567 sig.inputs_and_output = tcx.intern_type_list(&inputs_and_output);
570 // FIXME(eddyb) avoid having this snippet both here and in
571 // `Instance::fn_sig` (introduce `InstanceDef::fn_sig`?).
572 if let ty::InstanceDef::VtableShim(..) = instance {
573 // Modify fn(self, ...) to fn(self: *mut Self, ...)
574 let mut inputs_and_output = sig.inputs_and_output.to_vec();
575 let self_arg = &mut inputs_and_output[0];
576 debug_assert!(tcx.generics_of(def_id).has_self && *self_arg == tcx.types.self_param);
577 *self_arg = tcx.mk_mut_ptr(*self_arg);
578 sig.inputs_and_output = tcx.intern_type_list(&inputs_and_output);
581 let span = tcx.def_span(def_id);
583 debug!("build_call_shim: sig={:?}", sig);
585 let mut local_decls = local_decls_for_sig(&sig, span);
586 let source_info = SourceInfo::outermost(span);
588 let rcvr_place = || {
589 assert!(rcvr_adjustment.is_some());
590 Place::from(Local::new(1 + 0))
592 let mut statements = vec![];
594 let rcvr = rcvr_adjustment.map(|rcvr_adjustment| match rcvr_adjustment {
595 Adjustment::Identity => Operand::Move(rcvr_place()),
596 Adjustment::Deref => Operand::Move(tcx.mk_place_deref(rcvr_place())),
597 Adjustment::RefMut => {
598 // let rcvr = &mut rcvr;
599 let ref_rcvr = local_decls.push(
602 tcx.lifetimes.re_erased,
603 ty::TypeAndMut { ty: sig.inputs()[0], mutbl: hir::Mutability::Mut },
609 let borrow_kind = BorrowKind::Mut { allow_two_phase_borrow: false };
610 statements.push(Statement {
612 kind: StatementKind::Assign(Box::new((
613 Place::from(ref_rcvr),
614 Rvalue::Ref(tcx.lifetimes.re_erased, borrow_kind, rcvr_place()),
617 Operand::Move(Place::from(ref_rcvr))
621 let (callee, mut args) = match call_kind {
622 // `FnPtr` call has no receiver. Args are untupled below.
623 CallKind::Indirect(_) => (rcvr.unwrap(), vec![]),
625 // `FnDef` call with optional receiver.
626 CallKind::Direct(def_id) => {
627 let ty = tcx.type_of(def_id);
629 Operand::Constant(Box::new(Constant {
632 literal: ConstantKind::zero_sized(ty),
634 rcvr.into_iter().collect::<Vec<_>>(),
639 let mut arg_range = 0..sig.inputs().len();
641 // Take the `self` ("receiver") argument out of the range (it's adjusted above).
642 if rcvr_adjustment.is_some() {
643 arg_range.start += 1;
646 // Take the last argument, if we need to untuple it (handled below).
647 if untuple_args.is_some() {
651 // Pass all of the non-special arguments directly.
652 args.extend(arg_range.map(|i| Operand::Move(Place::from(Local::new(1 + i)))));
654 // Untuple the last argument, if we have to.
655 if let Some(untuple_args) = untuple_args {
656 let tuple_arg = Local::new(1 + (sig.inputs().len() - 1));
657 args.extend(untuple_args.iter().enumerate().map(|(i, ity)| {
658 Operand::Move(tcx.mk_place_field(Place::from(tuple_arg), Field::new(i), *ity))
662 let n_blocks = if let Some(Adjustment::RefMut) = rcvr_adjustment { 5 } else { 2 };
663 let mut blocks = IndexVec::with_capacity(n_blocks);
664 let block = |blocks: &mut IndexVec<_, _>, statements, kind, is_cleanup| {
665 blocks.push(BasicBlockData {
667 terminator: Some(Terminator { source_info, kind }),
676 TerminatorKind::Call {
679 destination: Place::return_place(),
680 target: Some(BasicBlock::new(1)),
681 cleanup: if let Some(Adjustment::RefMut) = rcvr_adjustment {
682 Some(BasicBlock::new(3))
692 if let Some(Adjustment::RefMut) = rcvr_adjustment {
693 // BB #1 - drop for Self
697 TerminatorKind::Drop { place: rcvr_place(), target: BasicBlock::new(2), unwind: None },
702 block(&mut blocks, vec![], TerminatorKind::Return, false);
703 if let Some(Adjustment::RefMut) = rcvr_adjustment {
704 // BB #3 - drop if closure panics
708 TerminatorKind::Drop { place: rcvr_place(), target: BasicBlock::new(4), unwind: None },
713 block(&mut blocks, vec![], TerminatorKind::Resume, true);
717 new_body(MirSource::from_instance(instance), blocks, local_decls, sig.inputs().len(), span);
719 if let Abi::RustCall = sig.abi {
720 body.spread_arg = Some(Local::new(sig.inputs().len()));
726 pub fn build_adt_ctor(tcx: TyCtxt<'_>, ctor_id: DefId) -> Body<'_> {
727 debug_assert!(tcx.is_constructor(ctor_id));
729 let param_env = tcx.param_env(ctor_id);
731 // Normalize the sig.
732 let sig = tcx.fn_sig(ctor_id).no_bound_vars().expect("LBR in ADT constructor signature");
733 let sig = tcx.normalize_erasing_regions(param_env, sig);
735 let ty::Adt(adt_def, substs) = sig.output().kind() else {
736 bug!("unexpected type for ADT ctor {:?}", sig.output());
739 debug!("build_ctor: ctor_id={:?} sig={:?}", ctor_id, sig);
741 let span = tcx.def_span(ctor_id);
743 let local_decls = local_decls_for_sig(&sig, span);
745 let source_info = SourceInfo::outermost(span);
747 let variant_index = if adt_def.is_enum() {
748 adt_def.variant_index_with_ctor_id(ctor_id)
753 // Generate the following MIR:
755 // (return as Variant).field0 = arg0;
756 // (return as Variant).field1 = arg1;
759 debug!("build_ctor: variant_index={:?}", variant_index);
761 let statements = expand_aggregate(
762 Place::return_place(),
763 adt_def.variant(variant_index).fields.iter().enumerate().map(|(idx, field_def)| {
764 (Operand::Move(Place::from(Local::new(idx + 1))), field_def.ty(tcx, substs))
766 AggregateKind::Adt(adt_def.did(), variant_index, substs, None, None),
772 let start_block = BasicBlockData {
774 terminator: Some(Terminator { source_info, kind: TerminatorKind::Return }),
778 let source = MirSource::item(ctor_id);
781 IndexVec::from_elem_n(start_block, 1),
787 rustc_middle::mir::dump_mir(tcx, None, "mir_map", &0, &body, |_, _| Ok(()));