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, 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::transform::{
19 add_call_guards, add_moves_for_packed_drops, no_landing_pads, remove_noop_landing_pads,
22 use crate::util::elaborate_drops::{self, DropElaborator, DropFlagMode, DropStyle};
23 use crate::util::expand_aggregate;
24 use crate::util::patch::MirPatch;
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), None)
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),
45 // HACK: we need the "real" argument types for the MIR,
46 // but because our substs are (Self, Args), where Args
47 // is a tuple, we must include the *concrete* argument
48 // types in the MIR. They will be substituted again with
49 // the param-substs, but because they are concrete, this
50 // will not do any harm.
51 let sig = tcx.erase_late_bound_regions(&ty.fn_sig(tcx));
52 let arg_tys = sig.inputs();
54 build_call_shim(tcx, instance, Some(adjustment), CallKind::Indirect(ty), Some(arg_tys))
56 // We are generating a call back to our def-id, which the
57 // codegen backend knows to turn to an actual call, be it
58 // a virtual call, or a direct call to a function for which
59 // indirect calls must be codegen'd differently than direct ones
60 // (such as `#[track_caller]`).
61 ty::InstanceDef::ReifyShim(def_id) => {
62 build_call_shim(tcx, instance, None, CallKind::Direct(def_id), None)
64 ty::InstanceDef::ClosureOnceShim { call_once: _ } => {
65 let fn_mut = tcx.require_lang_item(LangItem::FnMut, None);
67 .associated_items(fn_mut)
68 .in_definition_order()
69 .find(|it| it.kind == ty::AssocKind::Fn)
76 Some(Adjustment::RefMut),
77 CallKind::Direct(call_mut),
81 ty::InstanceDef::DropGlue(def_id, ty) => build_drop_shim(tcx, def_id, ty),
82 ty::InstanceDef::CloneShim(def_id, ty) => build_clone_shim(tcx, def_id, ty),
83 ty::InstanceDef::Virtual(..) => {
84 bug!("InstanceDef::Virtual ({:?}) is for direct calls only", instance)
86 ty::InstanceDef::Intrinsic(_) => {
87 bug!("creating shims from intrinsics ({:?}) is unsupported", instance)
90 debug!("make_shim({:?}) = untransformed {:?}", instance, result);
99 &add_moves_for_packed_drops::AddMovesForPackedDrops,
100 &no_landing_pads::NoLandingPads::new(tcx),
101 &remove_noop_landing_pads::RemoveNoopLandingPads,
102 &simplify::SimplifyCfg::new("make_shim"),
103 &add_call_guards::CriticalCallEdges,
107 debug!("make_shim({:?}) = {:?}", instance, result);
112 #[derive(Copy, Clone, Debug, PartialEq)]
114 /// Pass the receiver as-is.
117 /// We get passed `&[mut] self` and call the target with `*self`.
119 /// This either copies `self` (if `Self: Copy`, eg. for function items), or moves out of it
120 /// (for `VtableShim`, which effectively is passed `&own Self`).
123 /// We get passed `self: Self` and call the target with `&mut self`.
125 /// In this case we need to ensure that the `Self` is dropped after the call, as the callee
126 /// won't do it for us.
130 #[derive(Copy, Clone, Debug, PartialEq)]
131 enum CallKind<'tcx> {
132 /// Call the `FnPtr` that was passed as the receiver.
135 /// Call a known `FnDef`.
139 fn local_decls_for_sig<'tcx>(
140 sig: &ty::FnSig<'tcx>,
142 ) -> IndexVec<Local, LocalDecl<'tcx>> {
143 iter::once(LocalDecl::new(sig.output(), span))
144 .chain(sig.inputs().iter().map(|ity| LocalDecl::new(ity, span).immutable()))
148 fn build_drop_shim<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, ty: Option<Ty<'tcx>>) -> Body<'tcx> {
149 debug!("build_drop_shim(def_id={:?}, ty={:?})", def_id, ty);
151 // Check if this is a generator, if so, return the drop glue for it
152 if let Some(&ty::TyS { kind: ty::Generator(gen_def_id, substs, _), .. }) = ty {
153 let body = &**tcx.optimized_mir(gen_def_id).generator_drop.as_ref().unwrap();
154 return body.subst(tcx, substs);
157 let substs = if let Some(ty) = ty {
158 tcx.intern_substs(&[ty.into()])
160 InternalSubsts::identity_for_item(tcx, def_id)
162 let sig = tcx.fn_sig(def_id).subst(tcx, substs);
163 let sig = tcx.erase_late_bound_regions(&sig);
164 let span = tcx.def_span(def_id);
166 let source_info = SourceInfo::outermost(span);
168 let return_block = BasicBlock::new(1);
169 let mut blocks = IndexVec::with_capacity(2);
170 let block = |blocks: &mut IndexVec<_, _>, kind| {
171 blocks.push(BasicBlockData {
173 terminator: Some(Terminator { source_info, kind }),
177 block(&mut blocks, TerminatorKind::Goto { target: return_block });
178 block(&mut blocks, TerminatorKind::Return);
180 let mut body = new_body(blocks, local_decls_for_sig(&sig, span), sig.inputs().len(), span);
182 if let Some(..) = ty {
183 // The first argument (index 0), but add 1 for the return value.
184 let dropee_ptr = Place::from(Local::new(1 + 0));
185 if tcx.sess.opts.debugging_opts.mir_emit_retag {
186 // Function arguments should be retagged, and we make this one raw.
187 body.basic_blocks_mut()[START_BLOCK].statements.insert(
191 kind: StatementKind::Retag(RetagKind::Raw, box (dropee_ptr)),
196 let param_env = tcx.param_env_reveal_all_normalized(def_id);
198 DropShimElaborator { body: &body, patch: MirPatch::new(&body), tcx, param_env };
199 let dropee = tcx.mk_place_deref(dropee_ptr);
200 let resume_block = elaborator.patch.resume_block();
201 elaborate_drops::elaborate_drop(
207 elaborate_drops::Unwind::To(resume_block),
212 patch.apply(&mut body);
219 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
220 local_decls: IndexVec<Local, LocalDecl<'tcx>>,
226 IndexVec::from_elem_n(
227 SourceScopeData { span, parent_scope: None, local_data: ClearCrossCrate::Clear },
239 pub struct DropShimElaborator<'a, 'tcx> {
240 pub body: &'a Body<'tcx>,
241 pub patch: MirPatch<'tcx>,
242 pub tcx: TyCtxt<'tcx>,
243 pub param_env: ty::ParamEnv<'tcx>,
246 impl<'a, 'tcx> fmt::Debug for DropShimElaborator<'a, 'tcx> {
247 fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
252 impl<'a, 'tcx> DropElaborator<'a, 'tcx> for DropShimElaborator<'a, 'tcx> {
255 fn patch(&mut self) -> &mut MirPatch<'tcx> {
258 fn body(&self) -> &'a Body<'tcx> {
261 fn tcx(&self) -> TyCtxt<'tcx> {
264 fn param_env(&self) -> ty::ParamEnv<'tcx> {
268 fn drop_style(&self, _path: Self::Path, mode: DropFlagMode) -> DropStyle {
270 DropFlagMode::Shallow => {
271 // Drops for the contained fields are "shallow" and "static" - they will simply call
272 // the field's own drop glue.
275 DropFlagMode::Deep => {
276 // The top-level drop is "deep" and "open" - it will be elaborated to a drop ladder
277 // dropping each field contained in the value.
283 fn get_drop_flag(&mut self, _path: Self::Path) -> Option<Operand<'tcx>> {
287 fn clear_drop_flag(&mut self, _location: Location, _path: Self::Path, _mode: DropFlagMode) {}
289 fn field_subpath(&self, _path: Self::Path, _field: Field) -> Option<Self::Path> {
292 fn deref_subpath(&self, _path: Self::Path) -> Option<Self::Path> {
295 fn downcast_subpath(&self, _path: Self::Path, _variant: VariantIdx) -> Option<Self::Path> {
298 fn array_subpath(&self, _path: Self::Path, _index: u64, _size: u64) -> Option<Self::Path> {
303 /// Builds a `Clone::clone` shim for `self_ty`. Here, `def_id` is `Clone::clone`.
304 fn build_clone_shim<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, self_ty: Ty<'tcx>) -> Body<'tcx> {
305 debug!("build_clone_shim(def_id={:?})", def_id);
307 let param_env = tcx.param_env(def_id);
309 let mut builder = CloneShimBuilder::new(tcx, def_id, self_ty);
310 let is_copy = self_ty.is_copy_modulo_regions(tcx.at(builder.span), param_env);
312 let dest = Place::return_place();
313 let src = tcx.mk_place_deref(Place::from(Local::new(1 + 0)));
316 _ if is_copy => builder.copy_shim(),
317 ty::Array(ty, len) => {
318 let len = len.eval_usize(tcx, param_env);
319 builder.array_shim(dest, src, ty, len)
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 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.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 new_body(self.blocks, self.local_decls, self.sig.inputs().len(), self.span)
364 fn source_info(&self) -> SourceInfo {
365 SourceInfo::outermost(self.span)
370 statements: Vec<Statement<'tcx>>,
371 kind: TerminatorKind<'tcx>,
374 let source_info = self.source_info();
375 self.blocks.push(BasicBlockData {
377 terminator: Some(Terminator { source_info, kind }),
382 /// Gives the index of an upcoming BasicBlock, with an offset.
383 /// offset=0 will give you the index of the next BasicBlock,
384 /// offset=1 will give the index of the next-to-next block,
385 /// offset=-1 will give you the index of the last-created block
386 fn block_index_offset(&mut self, offset: usize) -> BasicBlock {
387 BasicBlock::new(self.blocks.len() + offset)
390 fn make_statement(&self, kind: StatementKind<'tcx>) -> Statement<'tcx> {
391 Statement { source_info: self.source_info(), kind }
394 fn copy_shim(&mut self) {
395 let rcvr = self.tcx.mk_place_deref(Place::from(Local::new(1 + 0)));
396 let ret_statement = self.make_statement(StatementKind::Assign(box (
397 Place::return_place(),
398 Rvalue::Use(Operand::Copy(rcvr)),
400 self.block(vec![ret_statement], TerminatorKind::Return, false);
403 fn make_place(&mut self, mutability: Mutability, ty: Ty<'tcx>) -> Place<'tcx> {
404 let span = self.span;
405 let mut local = LocalDecl::new(ty, span);
406 if mutability == Mutability::Not {
407 local = local.immutable();
409 Place::from(self.local_decls.push(local))
422 let substs = tcx.mk_substs_trait(ty, &[]);
424 // `func == Clone::clone(&ty) -> ty`
425 let func_ty = tcx.mk_fn_def(self.def_id, substs);
426 let func = Operand::Constant(box Constant {
429 literal: ty::Const::zero_sized(tcx, func_ty),
432 let ref_loc = self.make_place(
434 tcx.mk_ref(tcx.lifetimes.re_erased, ty::TypeAndMut { ty, mutbl: hir::Mutability::Not }),
437 // `let ref_loc: &ty = &src;`
438 let statement = self.make_statement(StatementKind::Assign(box (
440 Rvalue::Ref(tcx.lifetimes.re_erased, BorrowKind::Shared, src),
443 // `let loc = Clone::clone(ref_loc);`
446 TerminatorKind::Call {
448 args: vec![Operand::Move(ref_loc)],
449 destination: Some((dest, next)),
450 cleanup: Some(cleanup),
462 loop_body: BasicBlock,
463 loop_end: BasicBlock,
468 let cond = self.make_place(Mutability::Mut, tcx.types.bool);
469 let compute_cond = self.make_statement(StatementKind::Assign(box (
471 Rvalue::BinaryOp(BinOp::Ne, Operand::Copy(end), Operand::Copy(beg)),
474 // `if end != beg { goto loop_body; } else { goto loop_end; }`
477 TerminatorKind::if_(tcx, Operand::Move(cond), loop_body, loop_end),
482 fn make_usize(&self, value: u64) -> Box<Constant<'tcx>> {
486 literal: ty::Const::from_usize(self.tcx, value),
490 fn array_shim(&mut self, dest: Place<'tcx>, src: Place<'tcx>, ty: Ty<'tcx>, len: u64) {
492 let span = self.span;
494 let beg = self.local_decls.push(LocalDecl::new(tcx.types.usize, span));
495 let end = self.make_place(Mutability::Not, tcx.types.usize);
498 // `let mut beg = 0;`
502 self.make_statement(StatementKind::Assign(box (
504 Rvalue::Use(Operand::Constant(self.make_usize(0))),
506 self.make_statement(StatementKind::Assign(box (
508 Rvalue::Use(Operand::Constant(self.make_usize(len))),
511 self.block(inits, TerminatorKind::Goto { target: BasicBlock::new(1) }, false);
518 self.loop_header(Place::from(beg), end, BasicBlock::new(2), BasicBlock::new(4), false);
521 // `dest[i] = Clone::clone(src[beg])`;
522 // Goto #3 if ok, #5 if unwinding happens.
523 let dest_field = self.tcx.mk_place_index(dest, beg);
524 let src_field = self.tcx.mk_place_index(src, beg);
525 self.make_clone_call(dest_field, src_field, ty, BasicBlock::new(3), BasicBlock::new(5));
530 let statements = vec![self.make_statement(StatementKind::Assign(box (
534 Operand::Copy(Place::from(beg)),
535 Operand::Constant(self.make_usize(1)),
538 self.block(statements, TerminatorKind::Goto { target: BasicBlock::new(1) }, false);
542 self.block(vec![], TerminatorKind::Return, false);
546 // `let mut beg = 0;`
549 let beg = self.local_decls.push(LocalDecl::new(tcx.types.usize, span));
550 let init = self.make_statement(StatementKind::Assign(box (
552 Rvalue::Use(Operand::Constant(self.make_usize(0))),
554 self.block(vec![init], TerminatorKind::Goto { target: BasicBlock::new(6) }, true);
556 // BB #6 (cleanup): loop {
570 // `drop(dest[beg])`;
573 TerminatorKind::Drop {
574 place: self.tcx.mk_place_index(dest, beg),
575 target: BasicBlock::new(8),
584 let statement = self.make_statement(StatementKind::Assign(box (
588 Operand::Copy(Place::from(beg)),
589 Operand::Constant(self.make_usize(1)),
592 self.block(vec![statement], TerminatorKind::Goto { target: BasicBlock::new(6) }, true);
595 self.block(vec![], TerminatorKind::Resume, true);
598 fn tuple_like_shim<I>(&mut self, dest: Place<'tcx>, src: Place<'tcx>, tys: I)
600 I: Iterator<Item = Ty<'tcx>>,
602 let mut previous_field = None;
603 for (i, ity) in tys.enumerate() {
604 let field = Field::new(i);
605 let src_field = self.tcx.mk_place_field(src, field, ity);
607 let dest_field = self.tcx.mk_place_field(dest, field, ity);
609 // #(2i + 1) is the cleanup block for the previous clone operation
610 let cleanup_block = self.block_index_offset(1);
611 // #(2i + 2) is the next cloning block
612 // (or the Return terminator if this is the last block)
613 let next_block = self.block_index_offset(2);
616 // `dest.i = Clone::clone(&src.i);`
617 // Goto #(2i + 2) if ok, #(2i + 1) if unwinding happens.
618 self.make_clone_call(dest_field, src_field, ity, next_block, cleanup_block);
620 // BB #(2i + 1) (cleanup)
621 if let Some((previous_field, previous_cleanup)) = previous_field.take() {
622 // Drop previous field and goto previous cleanup block.
625 TerminatorKind::Drop {
626 place: previous_field,
627 target: previous_cleanup,
633 // Nothing to drop, just resume.
634 self.block(vec![], TerminatorKind::Resume, true);
637 previous_field = Some((dest_field, cleanup_block));
640 self.block(vec![], TerminatorKind::Return, false);
644 /// Builds a "call" shim for `instance`. The shim calls the
645 /// function specified by `call_kind`, first adjusting its first
646 /// argument according to `rcvr_adjustment`.
648 /// If `untuple_args` is a vec of types, the second argument of the
649 /// function will be untupled as these types.
650 fn build_call_shim<'tcx>(
652 instance: ty::InstanceDef<'tcx>,
653 rcvr_adjustment: Option<Adjustment>,
654 call_kind: CallKind<'tcx>,
655 untuple_args: Option<&[Ty<'tcx>]>,
658 "build_call_shim(instance={:?}, rcvr_adjustment={:?}, \
659 call_kind={:?}, untuple_args={:?})",
660 instance, rcvr_adjustment, call_kind, untuple_args
663 let def_id = instance.def_id();
664 let sig = tcx.fn_sig(def_id);
665 let mut sig = tcx.erase_late_bound_regions(&sig);
667 if let CallKind::Indirect(fnty) = call_kind {
668 // `sig` determines our local decls, and thus the callee type in the `Call` terminator. This
669 // can only be an `FnDef` or `FnPtr`, but currently will be `Self` since the types come from
670 // the implemented `FnX` trait.
672 // Apply the opposite adjustment to the MIR input.
673 let mut inputs_and_output = sig.inputs_and_output.to_vec();
675 // Initial signature is `fn(&? Self, Args) -> Self::Output` where `Args` is a tuple of the
676 // fn arguments. `Self` may be passed via (im)mutable reference or by-value.
677 assert_eq!(inputs_and_output.len(), 3);
679 // `Self` is always the original fn type `ty`. The MIR call terminator is only defined for
680 // `FnDef` and `FnPtr` callees, not the `Self` type param.
681 let self_arg = &mut inputs_and_output[0];
682 *self_arg = match rcvr_adjustment.unwrap() {
683 Adjustment::Identity => fnty,
684 Adjustment::Deref => tcx.mk_imm_ptr(fnty),
685 Adjustment::RefMut => tcx.mk_mut_ptr(fnty),
687 sig.inputs_and_output = tcx.intern_type_list(&inputs_and_output);
690 // FIXME(eddyb) avoid having this snippet both here and in
691 // `Instance::fn_sig` (introduce `InstanceDef::fn_sig`?).
692 if let ty::InstanceDef::VtableShim(..) = instance {
693 // Modify fn(self, ...) to fn(self: *mut Self, ...)
694 let mut inputs_and_output = sig.inputs_and_output.to_vec();
695 let self_arg = &mut inputs_and_output[0];
696 debug_assert!(tcx.generics_of(def_id).has_self && *self_arg == tcx.types.self_param);
697 *self_arg = tcx.mk_mut_ptr(*self_arg);
698 sig.inputs_and_output = tcx.intern_type_list(&inputs_and_output);
701 let span = tcx.def_span(def_id);
703 debug!("build_call_shim: sig={:?}", sig);
705 let mut local_decls = local_decls_for_sig(&sig, span);
706 let source_info = SourceInfo::outermost(span);
708 let rcvr_place = || {
709 assert!(rcvr_adjustment.is_some());
710 Place::from(Local::new(1 + 0))
712 let mut statements = vec![];
714 let rcvr = rcvr_adjustment.map(|rcvr_adjustment| match rcvr_adjustment {
715 Adjustment::Identity => Operand::Move(rcvr_place()),
716 Adjustment::Deref => Operand::Move(tcx.mk_place_deref(rcvr_place())),
717 Adjustment::RefMut => {
718 // let rcvr = &mut rcvr;
719 let ref_rcvr = local_decls.push(
722 tcx.lifetimes.re_erased,
723 ty::TypeAndMut { ty: sig.inputs()[0], mutbl: hir::Mutability::Mut },
729 let borrow_kind = BorrowKind::Mut { allow_two_phase_borrow: false };
730 statements.push(Statement {
732 kind: StatementKind::Assign(box (
733 Place::from(ref_rcvr),
734 Rvalue::Ref(tcx.lifetimes.re_erased, borrow_kind, rcvr_place()),
737 Operand::Move(Place::from(ref_rcvr))
741 let (callee, mut args) = match call_kind {
742 // `FnPtr` call has no receiver. Args are untupled below.
743 CallKind::Indirect(_) => (rcvr.unwrap(), vec![]),
745 // `FnDef` call with optional receiver.
746 CallKind::Direct(def_id) => {
747 let ty = tcx.type_of(def_id);
749 Operand::Constant(box Constant {
752 literal: ty::Const::zero_sized(tcx, ty),
754 rcvr.into_iter().collect::<Vec<_>>(),
759 let mut arg_range = 0..sig.inputs().len();
761 // Take the `self` ("receiver") argument out of the range (it's adjusted above).
762 if rcvr_adjustment.is_some() {
763 arg_range.start += 1;
766 // Take the last argument, if we need to untuple it (handled below).
767 if untuple_args.is_some() {
771 // Pass all of the non-special arguments directly.
772 args.extend(arg_range.map(|i| Operand::Move(Place::from(Local::new(1 + i)))));
774 // Untuple the last argument, if we have to.
775 if let Some(untuple_args) = untuple_args {
776 let tuple_arg = Local::new(1 + (sig.inputs().len() - 1));
777 args.extend(untuple_args.iter().enumerate().map(|(i, ity)| {
778 Operand::Move(tcx.mk_place_field(Place::from(tuple_arg), Field::new(i), *ity))
782 let n_blocks = if let Some(Adjustment::RefMut) = rcvr_adjustment { 5 } else { 2 };
783 let mut blocks = IndexVec::with_capacity(n_blocks);
784 let block = |blocks: &mut IndexVec<_, _>, statements, kind, is_cleanup| {
785 blocks.push(BasicBlockData {
787 terminator: Some(Terminator { source_info, kind }),
796 TerminatorKind::Call {
799 destination: Some((Place::return_place(), BasicBlock::new(1))),
800 cleanup: if let Some(Adjustment::RefMut) = rcvr_adjustment {
801 Some(BasicBlock::new(3))
811 if let Some(Adjustment::RefMut) = rcvr_adjustment {
812 // BB #1 - drop for Self
816 TerminatorKind::Drop { place: rcvr_place(), target: BasicBlock::new(2), unwind: None },
821 block(&mut blocks, vec![], TerminatorKind::Return, false);
822 if let Some(Adjustment::RefMut) = rcvr_adjustment {
823 // BB #3 - drop if closure panics
827 TerminatorKind::Drop { place: rcvr_place(), target: BasicBlock::new(4), unwind: None },
832 block(&mut blocks, vec![], TerminatorKind::Resume, true);
835 let mut body = new_body(blocks, local_decls, sig.inputs().len(), span);
837 if let Abi::RustCall = sig.abi {
838 body.spread_arg = Some(Local::new(sig.inputs().len()));
844 pub fn build_adt_ctor(tcx: TyCtxt<'_>, ctor_id: DefId) -> Body<'_> {
845 debug_assert!(tcx.is_constructor(ctor_id));
848 tcx.hir().span_if_local(ctor_id).unwrap_or_else(|| bug!("no span for ctor {:?}", ctor_id));
850 let param_env = tcx.param_env(ctor_id);
852 // Normalize the sig.
853 let sig = tcx.fn_sig(ctor_id).no_bound_vars().expect("LBR in ADT constructor signature");
854 let sig = tcx.normalize_erasing_regions(param_env, sig);
856 let (adt_def, substs) = match sig.output().kind {
857 ty::Adt(adt_def, substs) => (adt_def, substs),
858 _ => bug!("unexpected type for ADT ctor {:?}", sig.output()),
861 debug!("build_ctor: ctor_id={:?} sig={:?}", ctor_id, sig);
863 let local_decls = local_decls_for_sig(&sig, span);
865 let source_info = SourceInfo::outermost(span);
867 let variant_index = if adt_def.is_enum() {
868 adt_def.variant_index_with_ctor_id(ctor_id)
873 // Generate the following MIR:
875 // (return as Variant).field0 = arg0;
876 // (return as Variant).field1 = arg1;
879 debug!("build_ctor: variant_index={:?}", variant_index);
881 let statements = expand_aggregate(
882 Place::return_place(),
883 adt_def.variants[variant_index].fields.iter().enumerate().map(|(idx, field_def)| {
884 (Operand::Move(Place::from(Local::new(idx + 1))), field_def.ty(tcx, substs))
886 AggregateKind::Adt(adt_def, variant_index, substs, None, None),
892 let start_block = BasicBlockData {
894 terminator: Some(Terminator { source_info, kind: TerminatorKind::Return }),
899 new_body(IndexVec::from_elem_n(start_block, 1), local_decls, sig.inputs().len(), span);
901 crate::util::dump_mir(
906 crate::transform::MirSource::item(ctor_id),