2 use rustc::hir::def_id::DefId;
4 use rustc::ty::{self, Ty, TyCtxt};
5 use rustc::ty::layout::VariantIdx;
6 use rustc::ty::subst::{Subst, InternalSubsts};
7 use rustc::ty::query::Providers;
9 use rustc_index::vec::{IndexVec, Idx};
11 use rustc_target::spec::abi::Abi;
12 use syntax_pos::{Span, sym};
17 use crate::transform::{
18 add_moves_for_packed_drops, add_call_guards,
19 remove_noop_landing_pads, no_landing_pads, simplify, run_passes
21 use crate::util::elaborate_drops::{self, DropElaborator, DropStyle, DropFlagMode};
22 use crate::util::patch::MirPatch;
23 use crate::util::expand_aggregate;
25 pub fn provide(providers: &mut Providers<'_>) {
26 providers.mir_shims = make_shim;
29 fn make_shim<'tcx>(tcx: TyCtxt<'tcx>, instance: ty::InstanceDef<'tcx>) -> &'tcx BodyAndCache<'tcx> {
30 debug!("make_shim({:?})", instance);
32 let mut result = match instance {
33 ty::InstanceDef::Item(..) =>
34 bug!("item {:?} passed to make_shim", instance),
35 ty::InstanceDef::VtableShim(def_id) => {
39 Adjustment::DerefMove,
40 CallKind::Direct(def_id),
44 ty::InstanceDef::FnPtrShim(def_id, ty) => {
45 let trait_ = tcx.trait_of_item(def_id).unwrap();
46 let adjustment = match tcx.lang_items().fn_trait_kind(trait_) {
47 Some(ty::ClosureKind::FnOnce) => Adjustment::Identity,
48 Some(ty::ClosureKind::FnMut) |
49 Some(ty::ClosureKind::Fn) => Adjustment::Deref,
50 None => bug!("fn pointer {:?} is not an fn", ty)
52 // HACK: we need the "real" argument types for the MIR,
53 // but because our substs are (Self, Args), where Args
54 // is a tuple, we must include the *concrete* argument
55 // types in the MIR. They will be substituted again with
56 // the param-substs, but because they are concrete, this
57 // will not do any harm.
58 let sig = tcx.erase_late_bound_regions(&ty.fn_sig(tcx));
59 let arg_tys = sig.inputs();
69 // We are generating a call back to our def-id, which the
70 // codegen backend knows to turn to an actual call, be it
71 // a virtual call, or a direct call to a function for which
72 // indirect calls must be codegen'd differently than direct ones
73 // (such as `#[track_caller]`).
74 ty::InstanceDef::ReifyShim(def_id) => {
79 CallKind::Direct(def_id),
83 ty::InstanceDef::ClosureOnceShim { call_once: _ } => {
84 let fn_mut = tcx.lang_items().fn_mut_trait().unwrap();
86 .associated_items(fn_mut)
87 .find(|it| it.kind == ty::AssocKind::Method)
94 CallKind::Direct(call_mut),
98 ty::InstanceDef::DropGlue(def_id, ty) => {
99 build_drop_shim(tcx, def_id, ty)
101 ty::InstanceDef::CloneShim(def_id, ty) => {
102 let name = tcx.item_name(def_id);
103 if name == sym::clone {
104 build_clone_shim(tcx, def_id, ty)
105 } else if name == sym::clone_from {
106 debug!("make_shim({:?}: using default trait implementation", instance);
107 return tcx.optimized_mir(def_id);
109 bug!("builtin clone shim {:?} not supported", instance)
112 ty::InstanceDef::Virtual(..) => {
113 bug!("InstanceDef::Virtual ({:?}) is for direct calls only", instance)
115 ty::InstanceDef::Intrinsic(_) => {
116 bug!("creating shims from intrinsics ({:?}) is unsupported", instance)
119 debug!("make_shim({:?}) = untransformed {:?}", instance, result);
121 run_passes(tcx, &mut result, instance, None, MirPhase::Const, &[
122 &add_moves_for_packed_drops::AddMovesForPackedDrops,
123 &no_landing_pads::NoLandingPads::new(tcx),
124 &remove_noop_landing_pads::RemoveNoopLandingPads,
125 &simplify::SimplifyCfg::new("make_shim"),
126 &add_call_guards::CriticalCallEdges,
129 debug!("make_shim({:?}) = {:?}", instance, result);
131 result.ensure_predecessors();
132 tcx.arena.alloc(result)
135 #[derive(Copy, Clone, Debug, PartialEq)]
143 #[derive(Copy, Clone, Debug, PartialEq)]
149 fn temp_decl(mutability: Mutability, ty: Ty<'_>, span: Span) -> LocalDecl<'_> {
150 let source_info = SourceInfo { scope: OUTERMOST_SOURCE_SCOPE, span };
154 user_ty: UserTypeProjections::none(),
157 local_info: LocalInfo::Other,
162 fn local_decls_for_sig<'tcx>(sig: &ty::FnSig<'tcx>, span: Span)
163 -> IndexVec<Local, LocalDecl<'tcx>>
165 iter::once(temp_decl(Mutability::Mut, sig.output(), span))
166 .chain(sig.inputs().iter().map(
167 |ity| temp_decl(Mutability::Not, ity, span)))
171 fn build_drop_shim<'tcx>(
172 tcx: TyCtxt<'tcx>, def_id: DefId, ty: Option<Ty<'tcx>>
173 ) -> BodyAndCache<'tcx> {
174 debug!("build_drop_shim(def_id={:?}, ty={:?})", def_id, ty);
176 // Check if this is a generator, if so, return the drop glue for it
177 if let Some(&ty::TyS { kind: ty::Generator(gen_def_id, substs, _), .. }) = ty {
178 let body = &**tcx.optimized_mir(gen_def_id).generator_drop.as_ref().unwrap();
179 return body.subst(tcx, substs);
182 let substs = if let Some(ty) = ty {
183 tcx.intern_substs(&[ty.into()])
185 InternalSubsts::identity_for_item(tcx, def_id)
187 let sig = tcx.fn_sig(def_id).subst(tcx, substs);
188 let sig = tcx.erase_late_bound_regions(&sig);
189 let span = tcx.def_span(def_id);
191 let source_info = SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE };
193 let return_block = BasicBlock::new(1);
194 let mut blocks = IndexVec::with_capacity(2);
195 let block = |blocks: &mut IndexVec<_, _>, kind| {
196 blocks.push(BasicBlockData {
198 terminator: Some(Terminator { source_info, kind }),
202 block(&mut blocks, TerminatorKind::Goto { target: return_block });
203 block(&mut blocks, TerminatorKind::Return);
207 local_decls_for_sig(&sig, span),
211 let mut body = BodyAndCache::new(body);
213 if let Some(..) = ty {
214 // The first argument (index 0), but add 1 for the return value.
215 let dropee_ptr = Place::from(Local::new(1+0));
216 if tcx.sess.opts.debugging_opts.mir_emit_retag {
217 // Function arguments should be retagged, and we make this one raw.
218 body.basic_blocks_mut()[START_BLOCK].statements.insert(0, Statement {
220 kind: StatementKind::Retag(RetagKind::Raw, box(dropee_ptr.clone())),
224 let param_env = tcx.param_env(def_id).with_reveal_all();
225 let mut elaborator = DropShimElaborator {
227 patch: MirPatch::new(&body),
231 let dropee = tcx.mk_place_deref(dropee_ptr);
232 let resume_block = elaborator.patch.resume_block();
233 elaborate_drops::elaborate_drop(
239 elaborate_drops::Unwind::To(resume_block),
244 patch.apply(&mut body);
251 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
252 local_decls: IndexVec<Local, LocalDecl<'tcx>>,
258 IndexVec::from_elem_n(
259 SourceScopeData { span, parent_scope: None, local_data: ClearCrossCrate::Clear },
272 pub struct DropShimElaborator<'a, 'tcx> {
273 pub body: &'a Body<'tcx>,
274 pub patch: MirPatch<'tcx>,
275 pub tcx: TyCtxt<'tcx>,
276 pub param_env: ty::ParamEnv<'tcx>,
279 impl<'a, 'tcx> fmt::Debug for DropShimElaborator<'a, 'tcx> {
280 fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
285 impl<'a, 'tcx> DropElaborator<'a, 'tcx> for DropShimElaborator<'a, 'tcx> {
288 fn patch(&mut self) -> &mut MirPatch<'tcx> { &mut self.patch }
289 fn body(&self) -> &'a Body<'tcx> { self.body }
290 fn tcx(&self) -> TyCtxt<'tcx> {
293 fn param_env(&self) -> ty::ParamEnv<'tcx> { self.param_env }
295 fn drop_style(&self, _path: Self::Path, mode: DropFlagMode) -> DropStyle {
296 if let DropFlagMode::Shallow = mode {
303 fn get_drop_flag(&mut self, _path: Self::Path) -> Option<Operand<'tcx>> {
307 fn clear_drop_flag(&mut self, _location: Location, _path: Self::Path, _mode: DropFlagMode) {
310 fn field_subpath(&self, _path: Self::Path, _field: Field) -> Option<Self::Path> {
313 fn deref_subpath(&self, _path: Self::Path) -> Option<Self::Path> {
316 fn downcast_subpath(&self, _path: Self::Path, _variant: VariantIdx) -> Option<Self::Path> {
319 fn array_subpath(&self, _path: Self::Path, _index: u32, _size: u32) -> Option<Self::Path> {
324 /// Builds a `Clone::clone` shim for `self_ty`. Here, `def_id` is `Clone::clone`.
325 fn build_clone_shim<'tcx>(
329 ) -> BodyAndCache<'tcx> {
330 debug!("build_clone_shim(def_id={:?})", def_id);
332 let param_env = tcx.param_env(def_id);
334 let mut builder = CloneShimBuilder::new(tcx, def_id, self_ty);
335 let is_copy = self_ty.is_copy_modulo_regions(tcx, param_env, builder.span);
337 let dest = Place::return_place();
338 let src = tcx.mk_place_deref(Place::from(Local::new(1+0)));
341 _ if is_copy => builder.copy_shim(),
342 ty::Array(ty, len) => {
343 let len = len.eval_usize(tcx, param_env);
344 builder.array_shim(dest, src, ty, len)
346 ty::Closure(def_id, substs) => {
347 builder.tuple_like_shim(
349 substs.as_closure().upvar_tys(def_id, tcx)
352 ty::Tuple(..) => builder.tuple_like_shim(dest, src, self_ty.tuple_fields()),
354 bug!("clone shim for `{:?}` which is not `Copy` and is not an aggregate", self_ty)
358 BodyAndCache::new(builder.into_mir())
361 struct CloneShimBuilder<'tcx> {
364 local_decls: IndexVec<Local, LocalDecl<'tcx>>,
365 blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
367 sig: ty::FnSig<'tcx>,
370 impl CloneShimBuilder<'tcx> {
371 fn new(tcx: TyCtxt<'tcx>, def_id: DefId, self_ty: Ty<'tcx>) -> Self {
372 // we must subst the self_ty because it's
373 // otherwise going to be TySelf and we can't index
374 // or access fields of a Place of type TySelf.
375 let substs = tcx.mk_substs_trait(self_ty, &[]);
376 let sig = tcx.fn_sig(def_id).subst(tcx, substs);
377 let sig = tcx.erase_late_bound_regions(&sig);
378 let span = tcx.def_span(def_id);
383 local_decls: local_decls_for_sig(&sig, span),
384 blocks: IndexVec::new(),
390 fn into_mir(self) -> Body<'tcx> {
394 self.sig.inputs().len(),
399 fn source_info(&self) -> SourceInfo {
400 SourceInfo { span: self.span, scope: OUTERMOST_SOURCE_SCOPE }
405 statements: Vec<Statement<'tcx>>,
406 kind: TerminatorKind<'tcx>,
409 let source_info = self.source_info();
410 self.blocks.push(BasicBlockData {
412 terminator: Some(Terminator { source_info, kind }),
417 /// Gives the index of an upcoming BasicBlock, with an offset.
418 /// offset=0 will give you the index of the next BasicBlock,
419 /// offset=1 will give the index of the next-to-next block,
420 /// offset=-1 will give you the index of the last-created block
421 fn block_index_offset(&mut self, offset: usize) -> BasicBlock {
422 BasicBlock::new(self.blocks.len() + offset)
425 fn make_statement(&self, kind: StatementKind<'tcx>) -> Statement<'tcx> {
427 source_info: self.source_info(),
432 fn copy_shim(&mut self) {
433 let rcvr = self.tcx.mk_place_deref(Place::from(Local::new(1+0)));
434 let ret_statement = self.make_statement(
435 StatementKind::Assign(
437 Place::return_place(),
438 Rvalue::Use(Operand::Copy(rcvr))
442 self.block(vec![ret_statement], TerminatorKind::Return, false);
445 fn make_place(&mut self, mutability: Mutability, ty: Ty<'tcx>) -> Place<'tcx> {
446 let span = self.span;
447 Place::from(self.local_decls.push(temp_decl(mutability, ty, span)))
460 let substs = tcx.mk_substs_trait(ty, &[]);
462 // `func == Clone::clone(&ty) -> ty`
463 let func_ty = tcx.mk_fn_def(self.def_id, substs);
464 let func = Operand::Constant(box Constant {
467 literal: ty::Const::zero_sized(tcx, func_ty),
470 let ref_loc = self.make_place(
472 tcx.mk_ref(tcx.lifetimes.re_erased, ty::TypeAndMut {
474 mutbl: hir::Mutability::Immutable,
478 // `let ref_loc: &ty = &src;`
479 let statement = self.make_statement(
480 StatementKind::Assign(
483 Rvalue::Ref(tcx.lifetimes.re_erased, BorrowKind::Shared, src)
488 // `let loc = Clone::clone(ref_loc);`
489 self.block(vec![statement], TerminatorKind::Call {
491 args: vec![Operand::Move(ref_loc)],
492 destination: Some((dest, next)),
493 cleanup: Some(cleanup),
502 loop_body: BasicBlock,
503 loop_end: BasicBlock,
508 let cond = self.make_place(Mutability::Mut, tcx.types.bool);
509 let compute_cond = self.make_statement(
510 StatementKind::Assign(
513 Rvalue::BinaryOp(BinOp::Ne, Operand::Copy(end), Operand::Copy(beg))
518 // `if end != beg { goto loop_body; } else { goto loop_end; }`
521 TerminatorKind::if_(tcx, Operand::Move(cond), loop_body, loop_end),
526 fn make_usize(&self, value: u64) -> Box<Constant<'tcx>> {
530 literal: ty::Const::from_usize(self.tcx, value),
534 fn array_shim(&mut self, dest: Place<'tcx>, src: Place<'tcx>, ty: Ty<'tcx>, len: u64) {
536 let span = self.span;
538 let beg = self.local_decls.push(temp_decl(Mutability::Mut, tcx.types.usize, span));
539 let end = self.make_place(Mutability::Not, tcx.types.usize);
542 // `let mut beg = 0;`
547 StatementKind::Assign(
550 Rvalue::Use(Operand::Constant(self.make_usize(0)))
555 StatementKind::Assign(
558 Rvalue::Use(Operand::Constant(self.make_usize(len)))
563 self.block(inits, TerminatorKind::Goto { target: BasicBlock::new(1) }, false);
570 self.loop_header(Place::from(beg),
577 // `dest[i] = Clone::clone(src[beg])`;
578 // Goto #3 if ok, #5 if unwinding happens.
579 let dest_field = self.tcx.mk_place_index(dest.clone(), beg);
580 let src_field = self.tcx.mk_place_index(src, beg);
581 self.make_clone_call(dest_field, src_field, ty, BasicBlock::new(3),
587 let statements = vec![
589 StatementKind::Assign(
594 Operand::Copy(Place::from(beg)),
595 Operand::Constant(self.make_usize(1))
601 self.block(statements, TerminatorKind::Goto { target: BasicBlock::new(1) }, false);
605 self.block(vec![], TerminatorKind::Return, false);
609 // `let mut beg = 0;`
612 let beg = self.local_decls.push(temp_decl(Mutability::Mut, tcx.types.usize, span));
613 let init = self.make_statement(
614 StatementKind::Assign(
617 Rvalue::Use(Operand::Constant(self.make_usize(0)))
621 self.block(vec![init], TerminatorKind::Goto { target: BasicBlock::new(6) }, true);
623 // BB #6 (cleanup): loop {
628 self.loop_header(Place::from(beg), Place::from(end),
629 BasicBlock::new(7), BasicBlock::new(9), true);
632 // `drop(dest[beg])`;
633 self.block(vec![], TerminatorKind::Drop {
634 location: self.tcx.mk_place_index(dest, beg),
635 target: BasicBlock::new(8),
642 let statement = self.make_statement(
643 StatementKind::Assign(
648 Operand::Copy(Place::from(beg)),
649 Operand::Constant(self.make_usize(1))
654 self.block(vec![statement], TerminatorKind::Goto { target: BasicBlock::new(6) }, true);
657 self.block(vec![], TerminatorKind::Resume, true);
660 fn tuple_like_shim<I>(&mut self, dest: Place<'tcx>,
661 src: Place<'tcx>, tys: I)
662 where I: Iterator<Item = Ty<'tcx>> {
663 let mut previous_field = None;
664 for (i, ity) in tys.enumerate() {
665 let field = Field::new(i);
666 let src_field = self.tcx.mk_place_field(src.clone(), field, ity);
668 let dest_field = self.tcx.mk_place_field(dest.clone(), field, ity);
670 // #(2i + 1) is the cleanup block for the previous clone operation
671 let cleanup_block = self.block_index_offset(1);
672 // #(2i + 2) is the next cloning block
673 // (or the Return terminator if this is the last block)
674 let next_block = self.block_index_offset(2);
677 // `dest.i = Clone::clone(&src.i);`
678 // Goto #(2i + 2) if ok, #(2i + 1) if unwinding happens.
679 self.make_clone_call(
687 // BB #(2i + 1) (cleanup)
688 if let Some((previous_field, previous_cleanup)) = previous_field.take() {
689 // Drop previous field and goto previous cleanup block.
690 self.block(vec![], TerminatorKind::Drop {
691 location: previous_field,
692 target: previous_cleanup,
696 // Nothing to drop, just resume.
697 self.block(vec![], TerminatorKind::Resume, true);
700 previous_field = Some((dest_field, cleanup_block));
703 self.block(vec![], TerminatorKind::Return, false);
707 /// Builds a "call" shim for `instance`. The shim calls the
708 /// function specified by `call_kind`, first adjusting its first
709 /// argument according to `rcvr_adjustment`.
711 /// If `untuple_args` is a vec of types, the second argument of the
712 /// function will be untupled as these types.
713 fn build_call_shim<'tcx>(
715 instance: ty::InstanceDef<'tcx>,
716 rcvr_adjustment: Adjustment,
718 untuple_args: Option<&[Ty<'tcx>]>,
719 ) -> BodyAndCache<'tcx> {
720 debug!("build_call_shim(instance={:?}, rcvr_adjustment={:?}, \
721 call_kind={:?}, untuple_args={:?})",
722 instance, rcvr_adjustment, call_kind, untuple_args);
724 let def_id = instance.def_id();
725 let sig = tcx.fn_sig(def_id);
726 let mut sig = tcx.erase_late_bound_regions(&sig);
728 // FIXME(eddyb) avoid having this snippet both here and in
729 // `Instance::fn_sig` (introduce `InstanceDef::fn_sig`?).
730 if let ty::InstanceDef::VtableShim(..) = instance {
731 // Modify fn(self, ...) to fn(self: *mut Self, ...)
732 let mut inputs_and_output = sig.inputs_and_output.to_vec();
733 let self_arg = &mut inputs_and_output[0];
734 debug_assert!(tcx.generics_of(def_id).has_self && *self_arg == tcx.types.self_param);
735 *self_arg = tcx.mk_mut_ptr(*self_arg);
736 sig.inputs_and_output = tcx.intern_type_list(&inputs_and_output);
739 let span = tcx.def_span(def_id);
741 debug!("build_call_shim: sig={:?}", sig);
743 let mut local_decls = local_decls_for_sig(&sig, span);
744 let source_info = SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE };
746 let rcvr_arg = Local::new(1+0);
747 let rcvr_l = Place::from(rcvr_arg);
748 let mut statements = vec![];
750 let rcvr = match rcvr_adjustment {
751 Adjustment::Identity => Operand::Move(rcvr_l),
752 Adjustment::Deref => Operand::Copy(tcx.mk_place_deref(rcvr_l)),
753 Adjustment::DerefMove => Operand::Move(tcx.mk_place_deref(rcvr_l)),
754 Adjustment::RefMut => {
755 // let rcvr = &mut rcvr;
756 let ref_rcvr = local_decls.push(temp_decl(
758 tcx.mk_ref(tcx.lifetimes.re_erased, ty::TypeAndMut {
760 mutbl: hir::Mutability::Mutable
764 let borrow_kind = BorrowKind::Mut {
765 allow_two_phase_borrow: false,
767 statements.push(Statement {
769 kind: StatementKind::Assign(
771 Place::from(ref_rcvr),
772 Rvalue::Ref(tcx.lifetimes.re_erased, borrow_kind, rcvr_l)
776 Operand::Move(Place::from(ref_rcvr))
780 let (callee, mut args) = match call_kind {
781 CallKind::Indirect => (rcvr, vec![]),
782 CallKind::Direct(def_id) => {
783 let ty = tcx.type_of(def_id);
784 (Operand::Constant(box Constant {
787 literal: ty::Const::zero_sized(tcx, ty),
793 if let Some(untuple_args) = untuple_args {
794 args.extend(untuple_args.iter().enumerate().map(|(i, ity)| {
795 let arg_place = Place::from(Local::new(1+1));
796 Operand::Move(tcx.mk_place_field(arg_place, Field::new(i), *ity))
799 args.extend((1..sig.inputs().len()).map(|i| {
800 Operand::Move(Place::from(Local::new(1+i)))
804 let n_blocks = if let Adjustment::RefMut = rcvr_adjustment { 5 } else { 2 };
805 let mut blocks = IndexVec::with_capacity(n_blocks);
806 let block = |blocks: &mut IndexVec<_, _>, statements, kind, is_cleanup| {
807 blocks.push(BasicBlockData {
809 terminator: Some(Terminator { source_info, kind }),
815 block(&mut blocks, statements, TerminatorKind::Call {
818 destination: Some((Place::return_place(),
819 BasicBlock::new(1))),
820 cleanup: if let Adjustment::RefMut = rcvr_adjustment {
821 Some(BasicBlock::new(3))
828 if let Adjustment::RefMut = rcvr_adjustment {
829 // BB #1 - drop for Self
830 block(&mut blocks, vec![], TerminatorKind::Drop {
831 location: Place::from(rcvr_arg),
832 target: BasicBlock::new(2),
837 block(&mut blocks, vec![], TerminatorKind::Return, false);
838 if let Adjustment::RefMut = rcvr_adjustment {
839 // BB #3 - drop if closure panics
840 block(&mut blocks, vec![], TerminatorKind::Drop {
841 location: Place::from(rcvr_arg),
842 target: BasicBlock::new(4),
847 block(&mut blocks, vec![], TerminatorKind::Resume, true);
850 let mut body = new_body(
857 if let Abi::RustCall = sig.abi {
858 body.spread_arg = Some(Local::new(sig.inputs().len()));
860 BodyAndCache::new(body)
863 pub fn build_adt_ctor(tcx: TyCtxt<'_>, ctor_id: DefId) -> &BodyAndCache<'_> {
864 debug_assert!(tcx.is_constructor(ctor_id));
866 let span = tcx.hir().span_if_local(ctor_id)
867 .unwrap_or_else(|| bug!("no span for ctor {:?}", ctor_id));
869 let param_env = tcx.param_env(ctor_id);
871 // Normalize the sig.
872 let sig = tcx.fn_sig(ctor_id)
874 .expect("LBR in ADT constructor signature");
875 let sig = tcx.normalize_erasing_regions(param_env, sig);
877 let (adt_def, substs) = match sig.output().kind {
878 ty::Adt(adt_def, substs) => (adt_def, substs),
879 _ => bug!("unexpected type for ADT ctor {:?}", sig.output())
882 debug!("build_ctor: ctor_id={:?} sig={:?}", ctor_id, sig);
884 let local_decls = local_decls_for_sig(&sig, span);
886 let source_info = SourceInfo {
888 scope: OUTERMOST_SOURCE_SCOPE
891 let variant_index = if adt_def.is_enum() {
892 adt_def.variant_index_with_ctor_id(ctor_id)
897 // Generate the following MIR:
899 // (return as Variant).field0 = arg0;
900 // (return as Variant).field1 = arg1;
903 debug!("build_ctor: variant_index={:?}", variant_index);
905 let statements = expand_aggregate(
906 Place::return_place(),
908 .variants[variant_index]
912 .map(|(idx, field_def)| (
913 Operand::Move(Place::from(Local::new(idx + 1))),
914 field_def.ty(tcx, substs),
916 AggregateKind::Adt(adt_def, variant_index, substs, None, None),
921 let start_block = BasicBlockData {
923 terminator: Some(Terminator {
925 kind: TerminatorKind::Return,
931 IndexVec::from_elem_n(start_block, 1),
937 crate::util::dump_mir(
942 crate::transform::MirSource::item(ctor_id),
947 let mut body = BodyAndCache::new(body);
948 body.ensure_predecessors();
949 tcx.arena.alloc(body)