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 Body<'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 virtual call.
71 ty::InstanceDef::Virtual(def_id, _) |
72 // ...or we are generating a direct call to a function for which indirect calls must be
73 // codegen'd differently than direct ones (example: #[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::Intrinsic(_) => {
113 bug!("creating shims from intrinsics ({:?}) is unsupported", instance)
116 debug!("make_shim({:?}) = untransformed {:?}", instance, result);
118 run_passes(tcx, &mut result, instance, None, MirPhase::Const, &[
119 &add_moves_for_packed_drops::AddMovesForPackedDrops,
120 &no_landing_pads::NoLandingPads::new(tcx),
121 &remove_noop_landing_pads::RemoveNoopLandingPads,
122 &simplify::SimplifyCfg::new("make_shim"),
123 &add_call_guards::CriticalCallEdges,
126 debug!("make_shim({:?}) = {:?}", instance, result);
128 tcx.arena.alloc(result)
131 #[derive(Copy, Clone, Debug, PartialEq)]
139 #[derive(Copy, Clone, Debug, PartialEq)]
145 fn temp_decl(mutability: Mutability, ty: Ty<'_>, span: Span) -> LocalDecl<'_> {
146 let source_info = SourceInfo { scope: OUTERMOST_SOURCE_SCOPE, span };
150 user_ty: UserTypeProjections::none(),
153 visibility_scope: source_info.scope,
155 is_user_variable: None,
160 fn local_decls_for_sig<'tcx>(sig: &ty::FnSig<'tcx>, span: Span)
161 -> IndexVec<Local, LocalDecl<'tcx>>
163 iter::once(temp_decl(Mutability::Mut, sig.output(), span))
164 .chain(sig.inputs().iter().map(
165 |ity| temp_decl(Mutability::Not, ity, span)))
169 fn build_drop_shim<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, ty: Option<Ty<'tcx>>) -> Body<'tcx> {
170 debug!("build_drop_shim(def_id={:?}, ty={:?})", def_id, ty);
172 // Check if this is a generator, if so, return the drop glue for it
173 if let Some(&ty::TyS { kind: ty::Generator(gen_def_id, substs, _), .. }) = ty {
174 let body = &**tcx.optimized_mir(gen_def_id).generator_drop.as_ref().unwrap();
175 return body.subst(tcx, substs);
178 let substs = if let Some(ty) = ty {
179 tcx.intern_substs(&[ty.into()])
181 InternalSubsts::identity_for_item(tcx, def_id)
183 let sig = tcx.fn_sig(def_id).subst(tcx, substs);
184 let sig = tcx.erase_late_bound_regions(&sig);
185 let span = tcx.def_span(def_id);
187 let source_info = SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE };
189 let return_block = BasicBlock::new(1);
190 let mut blocks = IndexVec::with_capacity(2);
191 let block = |blocks: &mut IndexVec<_, _>, kind| {
192 blocks.push(BasicBlockData {
194 terminator: Some(Terminator { source_info, kind }),
198 block(&mut blocks, TerminatorKind::Goto { target: return_block });
199 block(&mut blocks, TerminatorKind::Return);
201 let mut body = Body::new(
203 IndexVec::from_elem_n(
204 SourceScopeData { span: span, parent_scope: None }, 1
206 ClearCrossCrate::Clear,
208 local_decls_for_sig(&sig, span),
216 if let Some(..) = ty {
217 // The first argument (index 0), but add 1 for the return value.
218 let dropee_ptr = Place::from(Local::new(1+0));
219 if tcx.sess.opts.debugging_opts.mir_emit_retag {
220 // Function arguments should be retagged, and we make this one raw.
221 body.basic_blocks_mut()[START_BLOCK].statements.insert(0, Statement {
223 kind: StatementKind::Retag(RetagKind::Raw, box(dropee_ptr.clone())),
227 let param_env = tcx.param_env(def_id).with_reveal_all();
228 let mut elaborator = DropShimElaborator {
230 patch: MirPatch::new(&body),
234 let dropee = tcx.mk_place_deref(dropee_ptr);
235 let resume_block = elaborator.patch.resume_block();
236 elaborate_drops::elaborate_drop(
242 elaborate_drops::Unwind::To(resume_block),
247 patch.apply(&mut body);
253 pub struct DropShimElaborator<'a, 'tcx> {
254 pub body: &'a Body<'tcx>,
255 pub patch: MirPatch<'tcx>,
256 pub tcx: TyCtxt<'tcx>,
257 pub param_env: ty::ParamEnv<'tcx>,
260 impl<'a, 'tcx> fmt::Debug for DropShimElaborator<'a, 'tcx> {
261 fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
266 impl<'a, 'tcx> DropElaborator<'a, 'tcx> for DropShimElaborator<'a, 'tcx> {
269 fn patch(&mut self) -> &mut MirPatch<'tcx> { &mut self.patch }
270 fn body(&self) -> &'a Body<'tcx> { self.body }
271 fn tcx(&self) -> TyCtxt<'tcx> {
274 fn param_env(&self) -> ty::ParamEnv<'tcx> { self.param_env }
276 fn drop_style(&self, _path: Self::Path, mode: DropFlagMode) -> DropStyle {
277 if let DropFlagMode::Shallow = mode {
284 fn get_drop_flag(&mut self, _path: Self::Path) -> Option<Operand<'tcx>> {
288 fn clear_drop_flag(&mut self, _location: Location, _path: Self::Path, _mode: DropFlagMode) {
291 fn field_subpath(&self, _path: Self::Path, _field: Field) -> Option<Self::Path> {
294 fn deref_subpath(&self, _path: Self::Path) -> Option<Self::Path> {
297 fn downcast_subpath(&self, _path: Self::Path, _variant: VariantIdx) -> Option<Self::Path> {
300 fn array_subpath(&self, _path: Self::Path, _index: u32, _size: u32) -> Option<Self::Path> {
305 /// Builds a `Clone::clone` shim for `self_ty`. Here, `def_id` is `Clone::clone`.
306 fn build_clone_shim<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, self_ty: Ty<'tcx>) -> Body<'tcx> {
307 debug!("build_clone_shim(def_id={:?})", def_id);
309 let param_env = tcx.param_env(def_id);
311 let mut builder = CloneShimBuilder::new(tcx, def_id, self_ty);
312 let is_copy = self_ty.is_copy_modulo_regions(tcx, param_env, builder.span);
314 let dest = Place::return_place();
315 let src = tcx.mk_place_deref(Place::from(Local::new(1+0)));
318 _ if is_copy => builder.copy_shim(),
319 ty::Array(ty, len) => {
320 let len = len.eval_usize(tcx, param_env);
321 builder.array_shim(dest, src, ty, len)
323 ty::Closure(def_id, substs) => {
324 builder.tuple_like_shim(
326 substs.as_closure().upvar_tys(def_id, tcx)
329 ty::Tuple(..) => builder.tuple_like_shim(dest, src, self_ty.tuple_fields()),
331 bug!("clone shim for `{:?}` which is not `Copy` and is not an aggregate", self_ty)
338 struct CloneShimBuilder<'tcx> {
341 local_decls: IndexVec<Local, LocalDecl<'tcx>>,
342 blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
344 sig: ty::FnSig<'tcx>,
347 impl CloneShimBuilder<'tcx> {
348 fn new(tcx: TyCtxt<'tcx>, def_id: DefId, self_ty: Ty<'tcx>) -> Self {
349 // we must subst the self_ty because it's
350 // otherwise going to be TySelf and we can't index
351 // or access fields of a Place of type TySelf.
352 let substs = tcx.mk_substs_trait(self_ty, &[]);
353 let sig = tcx.fn_sig(def_id).subst(tcx, substs);
354 let sig = tcx.erase_late_bound_regions(&sig);
355 let span = tcx.def_span(def_id);
360 local_decls: local_decls_for_sig(&sig, span),
361 blocks: IndexVec::new(),
367 fn into_mir(self) -> Body<'tcx> {
370 IndexVec::from_elem_n(
371 SourceScopeData { span: self.span, parent_scope: None }, 1
373 ClearCrossCrate::Clear,
377 self.sig.inputs().len(),
384 fn source_info(&self) -> SourceInfo {
385 SourceInfo { span: self.span, scope: OUTERMOST_SOURCE_SCOPE }
390 statements: Vec<Statement<'tcx>>,
391 kind: TerminatorKind<'tcx>,
394 let source_info = self.source_info();
395 self.blocks.push(BasicBlockData {
397 terminator: Some(Terminator { source_info, kind }),
402 /// Gives the index of an upcoming BasicBlock, with an offset.
403 /// offset=0 will give you the index of the next BasicBlock,
404 /// offset=1 will give the index of the next-to-next block,
405 /// offset=-1 will give you the index of the last-created block
406 fn block_index_offset(&mut self, offset: usize) -> BasicBlock {
407 BasicBlock::new(self.blocks.len() + offset)
410 fn make_statement(&self, kind: StatementKind<'tcx>) -> Statement<'tcx> {
412 source_info: self.source_info(),
417 fn copy_shim(&mut self) {
418 let rcvr = self.tcx.mk_place_deref(Place::from(Local::new(1+0)));
419 let ret_statement = self.make_statement(
420 StatementKind::Assign(
422 Place::return_place(),
423 Rvalue::Use(Operand::Copy(rcvr))
427 self.block(vec![ret_statement], TerminatorKind::Return, false);
430 fn make_place(&mut self, mutability: Mutability, ty: Ty<'tcx>) -> Place<'tcx> {
431 let span = self.span;
432 Place::from(self.local_decls.push(temp_decl(mutability, ty, span)))
445 let substs = tcx.mk_substs_trait(ty, &[]);
447 // `func == Clone::clone(&ty) -> ty`
448 let func_ty = tcx.mk_fn_def(self.def_id, substs);
449 let func = Operand::Constant(box Constant {
452 literal: ty::Const::zero_sized(tcx, func_ty),
455 let ref_loc = self.make_place(
457 tcx.mk_ref(tcx.lifetimes.re_erased, ty::TypeAndMut {
459 mutbl: hir::Mutability::MutImmutable,
463 // `let ref_loc: &ty = &src;`
464 let statement = self.make_statement(
465 StatementKind::Assign(
468 Rvalue::Ref(tcx.lifetimes.re_erased, BorrowKind::Shared, src)
473 // `let loc = Clone::clone(ref_loc);`
474 self.block(vec![statement], TerminatorKind::Call {
476 args: vec![Operand::Move(ref_loc)],
477 destination: Some((dest, next)),
478 cleanup: Some(cleanup),
487 loop_body: BasicBlock,
488 loop_end: BasicBlock,
493 let cond = self.make_place(Mutability::Mut, tcx.types.bool);
494 let compute_cond = self.make_statement(
495 StatementKind::Assign(
498 Rvalue::BinaryOp(BinOp::Ne, Operand::Copy(end), Operand::Copy(beg))
503 // `if end != beg { goto loop_body; } else { goto loop_end; }`
506 TerminatorKind::if_(tcx, Operand::Move(cond), loop_body, loop_end),
511 fn make_usize(&self, value: u64) -> Box<Constant<'tcx>> {
515 literal: ty::Const::from_usize(self.tcx, value),
519 fn array_shim(&mut self, dest: Place<'tcx>, src: Place<'tcx>, ty: Ty<'tcx>, len: u64) {
521 let span = self.span;
523 let beg = self.local_decls.push(temp_decl(Mutability::Mut, tcx.types.usize, span));
524 let end = self.make_place(Mutability::Not, tcx.types.usize);
527 // `let mut beg = 0;`
532 StatementKind::Assign(
535 Rvalue::Use(Operand::Constant(self.make_usize(0)))
540 StatementKind::Assign(
543 Rvalue::Use(Operand::Constant(self.make_usize(len)))
548 self.block(inits, TerminatorKind::Goto { target: BasicBlock::new(1) }, false);
555 self.loop_header(Place::from(beg),
562 // `dest[i] = Clone::clone(src[beg])`;
563 // Goto #3 if ok, #5 if unwinding happens.
564 let dest_field = self.tcx.mk_place_index(dest.clone(), beg);
565 let src_field = self.tcx.mk_place_index(src, beg);
566 self.make_clone_call(dest_field, src_field, ty, BasicBlock::new(3),
572 let statements = vec![
574 StatementKind::Assign(
579 Operand::Copy(Place::from(beg)),
580 Operand::Constant(self.make_usize(1))
586 self.block(statements, TerminatorKind::Goto { target: BasicBlock::new(1) }, false);
590 self.block(vec![], TerminatorKind::Return, false);
594 // `let mut beg = 0;`
597 let beg = self.local_decls.push(temp_decl(Mutability::Mut, tcx.types.usize, span));
598 let init = self.make_statement(
599 StatementKind::Assign(
602 Rvalue::Use(Operand::Constant(self.make_usize(0)))
606 self.block(vec![init], TerminatorKind::Goto { target: BasicBlock::new(6) }, true);
608 // BB #6 (cleanup): loop {
613 self.loop_header(Place::from(beg), Place::from(end),
614 BasicBlock::new(7), BasicBlock::new(9), true);
617 // `drop(dest[beg])`;
618 self.block(vec![], TerminatorKind::Drop {
619 location: self.tcx.mk_place_index(dest, beg),
620 target: BasicBlock::new(8),
627 let statement = self.make_statement(
628 StatementKind::Assign(
633 Operand::Copy(Place::from(beg)),
634 Operand::Constant(self.make_usize(1))
639 self.block(vec![statement], TerminatorKind::Goto { target: BasicBlock::new(6) }, true);
642 self.block(vec![], TerminatorKind::Resume, true);
645 fn tuple_like_shim<I>(&mut self, dest: Place<'tcx>,
646 src: Place<'tcx>, tys: I)
647 where I: Iterator<Item = Ty<'tcx>> {
648 let mut previous_field = None;
649 for (i, ity) in tys.enumerate() {
650 let field = Field::new(i);
651 let src_field = self.tcx.mk_place_field(src.clone(), field, ity);
653 let dest_field = self.tcx.mk_place_field(dest.clone(), field, ity);
655 // #(2i + 1) is the cleanup block for the previous clone operation
656 let cleanup_block = self.block_index_offset(1);
657 // #(2i + 2) is the next cloning block
658 // (or the Return terminator if this is the last block)
659 let next_block = self.block_index_offset(2);
662 // `dest.i = Clone::clone(&src.i);`
663 // Goto #(2i + 2) if ok, #(2i + 1) if unwinding happens.
664 self.make_clone_call(
672 // BB #(2i + 1) (cleanup)
673 if let Some((previous_field, previous_cleanup)) = previous_field.take() {
674 // Drop previous field and goto previous cleanup block.
675 self.block(vec![], TerminatorKind::Drop {
676 location: previous_field,
677 target: previous_cleanup,
681 // Nothing to drop, just resume.
682 self.block(vec![], TerminatorKind::Resume, true);
685 previous_field = Some((dest_field, cleanup_block));
688 self.block(vec![], TerminatorKind::Return, false);
692 /// Builds a "call" shim for `def_id`. The shim calls the
693 /// function specified by `call_kind`, first adjusting its first
694 /// argument according to `rcvr_adjustment`.
696 /// If `untuple_args` is a vec of types, the second argument of the
697 /// function will be untupled as these types.
698 fn build_call_shim<'tcx>(
701 rcvr_adjustment: Adjustment,
703 untuple_args: Option<&[Ty<'tcx>]>,
705 debug!("build_call_shim(def_id={:?}, rcvr_adjustment={:?}, \
706 call_kind={:?}, untuple_args={:?})",
707 def_id, rcvr_adjustment, call_kind, untuple_args);
709 let sig = tcx.fn_sig(def_id);
710 let sig = tcx.erase_late_bound_regions(&sig);
711 let span = tcx.def_span(def_id);
713 debug!("build_call_shim: sig={:?}", sig);
715 let mut local_decls = local_decls_for_sig(&sig, span);
716 let source_info = SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE };
718 let rcvr_arg = Local::new(1+0);
719 let rcvr_l = Place::from(rcvr_arg);
720 let mut statements = vec![];
722 let rcvr = match rcvr_adjustment {
723 Adjustment::Identity => Operand::Move(rcvr_l),
724 Adjustment::Deref => Operand::Copy(tcx.mk_place_deref(rcvr_l)),
725 Adjustment::DerefMove => {
726 // fn(Self, ...) -> fn(*mut Self, ...)
727 let arg_ty = local_decls[rcvr_arg].ty;
728 debug_assert!(tcx.generics_of(def_id).has_self && arg_ty == tcx.types.self_param);
729 local_decls[rcvr_arg].ty = tcx.mk_mut_ptr(arg_ty);
731 Operand::Move(tcx.mk_place_deref(rcvr_l))
733 Adjustment::RefMut => {
734 // let rcvr = &mut rcvr;
735 let ref_rcvr = local_decls.push(temp_decl(
737 tcx.mk_ref(tcx.lifetimes.re_erased, ty::TypeAndMut {
739 mutbl: hir::Mutability::MutMutable
743 let borrow_kind = BorrowKind::Mut {
744 allow_two_phase_borrow: false,
746 statements.push(Statement {
748 kind: StatementKind::Assign(
750 Place::from(ref_rcvr),
751 Rvalue::Ref(tcx.lifetimes.re_erased, borrow_kind, rcvr_l)
755 Operand::Move(Place::from(ref_rcvr))
759 let (callee, mut args) = match call_kind {
760 CallKind::Indirect => (rcvr, vec![]),
761 CallKind::Direct(def_id) => {
762 let ty = tcx.type_of(def_id);
763 (Operand::Constant(box Constant {
766 literal: ty::Const::zero_sized(tcx, ty),
772 if let Some(untuple_args) = untuple_args {
773 args.extend(untuple_args.iter().enumerate().map(|(i, ity)| {
774 let arg_place = Place::from(Local::new(1+1));
775 Operand::Move(tcx.mk_place_field(arg_place, Field::new(i), *ity))
778 args.extend((1..sig.inputs().len()).map(|i| {
779 Operand::Move(Place::from(Local::new(1+i)))
783 let n_blocks = if let Adjustment::RefMut = rcvr_adjustment { 5 } else { 2 };
784 let mut blocks = IndexVec::with_capacity(n_blocks);
785 let block = |blocks: &mut IndexVec<_, _>, statements, kind, is_cleanup| {
786 blocks.push(BasicBlockData {
788 terminator: Some(Terminator { source_info, kind }),
794 block(&mut blocks, statements, TerminatorKind::Call {
797 destination: Some((Place::return_place(),
798 BasicBlock::new(1))),
799 cleanup: if let Adjustment::RefMut = rcvr_adjustment {
800 Some(BasicBlock::new(3))
807 if let Adjustment::RefMut = rcvr_adjustment {
808 // BB #1 - drop for Self
809 block(&mut blocks, vec![], TerminatorKind::Drop {
810 location: Place::from(rcvr_arg),
811 target: BasicBlock::new(2),
816 block(&mut blocks, vec![], TerminatorKind::Return, false);
817 if let Adjustment::RefMut = rcvr_adjustment {
818 // BB #3 - drop if closure panics
819 block(&mut blocks, vec![], TerminatorKind::Drop {
820 location: Place::from(rcvr_arg),
821 target: BasicBlock::new(4),
826 block(&mut blocks, vec![], TerminatorKind::Resume, true);
829 let mut body = Body::new(
831 IndexVec::from_elem_n(
832 SourceScopeData { span: span, parent_scope: None }, 1
834 ClearCrossCrate::Clear,
843 if let Abi::RustCall = sig.abi {
844 body.spread_arg = Some(Local::new(sig.inputs().len()));
849 pub fn build_adt_ctor(tcx: TyCtxt<'_>, ctor_id: DefId) -> &Body<'_> {
850 debug_assert!(tcx.is_constructor(ctor_id));
852 let span = tcx.hir().span_if_local(ctor_id)
853 .unwrap_or_else(|| bug!("no span for ctor {:?}", ctor_id));
855 let param_env = tcx.param_env(ctor_id);
857 // Normalize the sig.
858 let sig = tcx.fn_sig(ctor_id)
860 .expect("LBR in ADT constructor signature");
861 let sig = tcx.normalize_erasing_regions(param_env, sig);
863 let (adt_def, substs) = match sig.output().kind {
864 ty::Adt(adt_def, substs) => (adt_def, substs),
865 _ => bug!("unexpected type for ADT ctor {:?}", sig.output())
868 debug!("build_ctor: ctor_id={:?} sig={:?}", ctor_id, sig);
870 let local_decls = local_decls_for_sig(&sig, span);
872 let source_info = SourceInfo {
874 scope: OUTERMOST_SOURCE_SCOPE
877 let variant_index = if adt_def.is_enum() {
878 adt_def.variant_index_with_ctor_id(ctor_id)
883 // Generate the following MIR:
885 // (return as Variant).field0 = arg0;
886 // (return as Variant).field1 = arg1;
889 debug!("build_ctor: variant_index={:?}", variant_index);
891 let statements = expand_aggregate(
892 Place::return_place(),
894 .variants[variant_index]
898 .map(|(idx, field_def)| (
899 Operand::Move(Place::from(Local::new(idx + 1))),
900 field_def.ty(tcx, substs),
902 AggregateKind::Adt(adt_def, variant_index, substs, None, None),
907 let start_block = BasicBlockData {
909 terminator: Some(Terminator {
911 kind: TerminatorKind::Return,
916 let body = Body::new(
917 IndexVec::from_elem_n(start_block, 1),
918 IndexVec::from_elem_n(
919 SourceScopeData { span: span, parent_scope: None }, 1
921 ClearCrossCrate::Clear,
931 crate::util::dump_mir(
936 crate::transform::MirSource::item(ctor_id),
941 tcx.arena.alloc(body)