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))
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: _ } => {
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))
67 ty::InstanceDef::DropGlue(def_id, ty) => build_drop_shim(tcx, def_id, ty),
68 ty::InstanceDef::CloneShim(def_id, ty) => build_clone_shim(tcx, def_id, ty),
69 ty::InstanceDef::Virtual(..) => {
70 bug!("InstanceDef::Virtual ({:?}) is for direct calls only", instance)
72 ty::InstanceDef::Intrinsic(_) => {
73 bug!("creating shims from intrinsics ({:?}) is unsupported", instance)
76 debug!("make_shim({:?}) = untransformed {:?}", instance, result);
83 &add_moves_for_packed_drops::AddMovesForPackedDrops,
84 &no_landing_pads::NoLandingPads::new(tcx),
85 &remove_noop_landing_pads::RemoveNoopLandingPads,
86 &simplify::SimplifyCfg::new("make_shim"),
87 &add_call_guards::CriticalCallEdges,
91 debug!("make_shim({:?}) = {:?}", instance, result);
96 #[derive(Copy, Clone, Debug, PartialEq)]
98 /// Pass the receiver as-is.
101 /// We get passed `&[mut] self` and call the target with `*self`.
103 /// This either copies `self` (if `Self: Copy`, eg. for function items), or moves out of it
104 /// (for `VtableShim`, which effectively is passed `&own Self`).
107 /// We get passed `self: Self` and call the target with `&mut self`.
109 /// In this case we need to ensure that the `Self` is dropped after the call, as the callee
110 /// won't do it for us.
114 #[derive(Copy, Clone, Debug, PartialEq)]
115 enum CallKind<'tcx> {
116 /// Call the `FnPtr` that was passed as the receiver.
119 /// Call a known `FnDef`.
123 fn local_decls_for_sig<'tcx>(
124 sig: &ty::FnSig<'tcx>,
126 ) -> IndexVec<Local, LocalDecl<'tcx>> {
127 iter::once(LocalDecl::new(sig.output(), span))
128 .chain(sig.inputs().iter().map(|ity| LocalDecl::new(ity, span).immutable()))
132 fn build_drop_shim<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, ty: Option<Ty<'tcx>>) -> Body<'tcx> {
133 debug!("build_drop_shim(def_id={:?}, ty={:?})", def_id, ty);
135 // Check if this is a generator, if so, return the drop glue for it
136 if let Some(&ty::Generator(gen_def_id, substs, _)) = ty.map(|ty| ty.kind()) {
137 let body = &**tcx.optimized_mir(gen_def_id).generator_drop.as_ref().unwrap();
138 return body.subst(tcx, substs);
141 let substs = if let Some(ty) = ty {
142 tcx.intern_substs(&[ty.into()])
144 InternalSubsts::identity_for_item(tcx, def_id)
146 let sig = tcx.fn_sig(def_id).subst(tcx, substs);
147 let sig = tcx.erase_late_bound_regions(&sig);
148 let span = tcx.def_span(def_id);
150 let source_info = SourceInfo::outermost(span);
152 let return_block = BasicBlock::new(1);
153 let mut blocks = IndexVec::with_capacity(2);
154 let block = |blocks: &mut IndexVec<_, _>, kind| {
155 blocks.push(BasicBlockData {
157 terminator: Some(Terminator { source_info, kind }),
161 block(&mut blocks, TerminatorKind::Goto { target: return_block });
162 block(&mut blocks, TerminatorKind::Return);
164 let source = MirSource::from_instance(ty::InstanceDef::DropGlue(def_id, ty));
166 new_body(source, blocks, local_decls_for_sig(&sig, span), sig.inputs().len(), span);
168 if let Some(..) = ty {
169 // The first argument (index 0), but add 1 for the return value.
170 let dropee_ptr = Place::from(Local::new(1 + 0));
171 if tcx.sess.opts.debugging_opts.mir_emit_retag {
172 // Function arguments should be retagged, and we make this one raw.
173 body.basic_blocks_mut()[START_BLOCK].statements.insert(
177 kind: StatementKind::Retag(RetagKind::Raw, box (dropee_ptr)),
182 let param_env = tcx.param_env_reveal_all_normalized(def_id);
184 DropShimElaborator { body: &body, patch: MirPatch::new(&body), tcx, param_env };
185 let dropee = tcx.mk_place_deref(dropee_ptr);
186 let resume_block = elaborator.patch.resume_block();
187 elaborate_drops::elaborate_drop(
193 elaborate_drops::Unwind::To(resume_block),
198 patch.apply(&mut body);
205 source: MirSource<'tcx>,
206 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
207 local_decls: IndexVec<Local, LocalDecl<'tcx>>,
214 IndexVec::from_elem_n(
215 SourceScopeData { span, parent_scope: None, local_data: ClearCrossCrate::Clear },
227 pub struct DropShimElaborator<'a, 'tcx> {
228 pub body: &'a Body<'tcx>,
229 pub patch: MirPatch<'tcx>,
230 pub tcx: TyCtxt<'tcx>,
231 pub param_env: ty::ParamEnv<'tcx>,
234 impl<'a, 'tcx> fmt::Debug for DropShimElaborator<'a, 'tcx> {
235 fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
240 impl<'a, 'tcx> DropElaborator<'a, 'tcx> for DropShimElaborator<'a, 'tcx> {
243 fn patch(&mut self) -> &mut MirPatch<'tcx> {
246 fn body(&self) -> &'a Body<'tcx> {
249 fn tcx(&self) -> TyCtxt<'tcx> {
252 fn param_env(&self) -> ty::ParamEnv<'tcx> {
256 fn drop_style(&self, _path: Self::Path, mode: DropFlagMode) -> DropStyle {
258 DropFlagMode::Shallow => {
259 // Drops for the contained fields are "shallow" and "static" - they will simply call
260 // the field's own drop glue.
263 DropFlagMode::Deep => {
264 // The top-level drop is "deep" and "open" - it will be elaborated to a drop ladder
265 // dropping each field contained in the value.
271 fn get_drop_flag(&mut self, _path: Self::Path) -> Option<Operand<'tcx>> {
275 fn clear_drop_flag(&mut self, _location: Location, _path: Self::Path, _mode: DropFlagMode) {}
277 fn field_subpath(&self, _path: Self::Path, _field: Field) -> Option<Self::Path> {
280 fn deref_subpath(&self, _path: Self::Path) -> Option<Self::Path> {
283 fn downcast_subpath(&self, _path: Self::Path, _variant: VariantIdx) -> Option<Self::Path> {
286 fn array_subpath(&self, _path: Self::Path, _index: u64, _size: u64) -> Option<Self::Path> {
291 /// Builds a `Clone::clone` shim for `self_ty`. Here, `def_id` is `Clone::clone`.
292 fn build_clone_shim<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, self_ty: Ty<'tcx>) -> Body<'tcx> {
293 debug!("build_clone_shim(def_id={:?})", def_id);
295 let param_env = tcx.param_env(def_id);
297 let mut builder = CloneShimBuilder::new(tcx, def_id, self_ty);
298 let is_copy = self_ty.is_copy_modulo_regions(tcx.at(builder.span), param_env);
300 let dest = Place::return_place();
301 let src = tcx.mk_place_deref(Place::from(Local::new(1 + 0)));
303 match self_ty.kind() {
304 _ if is_copy => builder.copy_shim(),
305 ty::Array(ty, len) => {
306 let len = len.eval_usize(tcx, param_env);
307 builder.array_shim(dest, src, ty, len)
309 ty::Closure(_, substs) => {
310 builder.tuple_like_shim(dest, src, substs.as_closure().upvar_tys())
312 ty::Tuple(..) => builder.tuple_like_shim(dest, src, self_ty.tuple_fields()),
313 _ => bug!("clone shim for `{:?}` which is not `Copy` and is not an aggregate", self_ty),
319 struct CloneShimBuilder<'tcx> {
322 local_decls: IndexVec<Local, LocalDecl<'tcx>>,
323 blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
325 sig: ty::FnSig<'tcx>,
328 impl CloneShimBuilder<'tcx> {
329 fn new(tcx: TyCtxt<'tcx>, def_id: DefId, self_ty: Ty<'tcx>) -> Self {
330 // we must subst the self_ty because it's
331 // otherwise going to be TySelf and we can't index
332 // or access fields of a Place of type TySelf.
333 let substs = tcx.mk_substs_trait(self_ty, &[]);
334 let sig = tcx.fn_sig(def_id).subst(tcx, substs);
335 let sig = tcx.erase_late_bound_regions(&sig);
336 let span = tcx.def_span(def_id);
341 local_decls: local_decls_for_sig(&sig, span),
342 blocks: IndexVec::new(),
348 fn into_mir(self) -> Body<'tcx> {
349 let source = MirSource::from_instance(ty::InstanceDef::CloneShim(
351 self.sig.inputs_and_output[0],
353 new_body(source, self.blocks, self.local_decls, self.sig.inputs().len(), self.span)
356 fn source_info(&self) -> SourceInfo {
357 SourceInfo::outermost(self.span)
362 statements: Vec<Statement<'tcx>>,
363 kind: TerminatorKind<'tcx>,
366 let source_info = self.source_info();
367 self.blocks.push(BasicBlockData {
369 terminator: Some(Terminator { source_info, kind }),
374 /// Gives the index of an upcoming BasicBlock, with an offset.
375 /// offset=0 will give you the index of the next BasicBlock,
376 /// offset=1 will give the index of the next-to-next block,
377 /// offset=-1 will give you the index of the last-created block
378 fn block_index_offset(&mut self, offset: usize) -> BasicBlock {
379 BasicBlock::new(self.blocks.len() + offset)
382 fn make_statement(&self, kind: StatementKind<'tcx>) -> Statement<'tcx> {
383 Statement { source_info: self.source_info(), kind }
386 fn copy_shim(&mut self) {
387 let rcvr = self.tcx.mk_place_deref(Place::from(Local::new(1 + 0)));
388 let ret_statement = self.make_statement(StatementKind::Assign(box (
389 Place::return_place(),
390 Rvalue::Use(Operand::Copy(rcvr)),
392 self.block(vec![ret_statement], TerminatorKind::Return, false);
395 fn make_place(&mut self, mutability: Mutability, ty: Ty<'tcx>) -> Place<'tcx> {
396 let span = self.span;
397 let mut local = LocalDecl::new(ty, span);
398 if mutability == Mutability::Not {
399 local = local.immutable();
401 Place::from(self.local_decls.push(local))
414 let substs = tcx.mk_substs_trait(ty, &[]);
416 // `func == Clone::clone(&ty) -> ty`
417 let func_ty = tcx.mk_fn_def(self.def_id, substs);
418 let func = Operand::Constant(box Constant {
421 literal: ty::Const::zero_sized(tcx, func_ty),
424 let ref_loc = self.make_place(
426 tcx.mk_ref(tcx.lifetimes.re_erased, ty::TypeAndMut { ty, mutbl: hir::Mutability::Not }),
429 // `let ref_loc: &ty = &src;`
430 let statement = self.make_statement(StatementKind::Assign(box (
432 Rvalue::Ref(tcx.lifetimes.re_erased, BorrowKind::Shared, src),
435 // `let loc = Clone::clone(ref_loc);`
438 TerminatorKind::Call {
440 args: vec![Operand::Move(ref_loc)],
441 destination: Some((dest, next)),
442 cleanup: Some(cleanup),
454 loop_body: BasicBlock,
455 loop_end: BasicBlock,
460 let cond = self.make_place(Mutability::Mut, tcx.types.bool);
461 let compute_cond = self.make_statement(StatementKind::Assign(box (
463 Rvalue::BinaryOp(BinOp::Ne, Operand::Copy(end), Operand::Copy(beg)),
466 // `if end != beg { goto loop_body; } else { goto loop_end; }`
469 TerminatorKind::if_(tcx, Operand::Move(cond), loop_body, loop_end),
474 fn make_usize(&self, value: u64) -> Box<Constant<'tcx>> {
478 literal: ty::Const::from_usize(self.tcx, value),
482 fn array_shim(&mut self, dest: Place<'tcx>, src: Place<'tcx>, ty: Ty<'tcx>, len: u64) {
484 let span = self.span;
486 let beg = self.local_decls.push(LocalDecl::new(tcx.types.usize, span));
487 let end = self.make_place(Mutability::Not, tcx.types.usize);
490 // `let mut beg = 0;`
494 self.make_statement(StatementKind::Assign(box (
496 Rvalue::Use(Operand::Constant(self.make_usize(0))),
498 self.make_statement(StatementKind::Assign(box (
500 Rvalue::Use(Operand::Constant(self.make_usize(len))),
503 self.block(inits, TerminatorKind::Goto { target: BasicBlock::new(1) }, false);
510 self.loop_header(Place::from(beg), end, BasicBlock::new(2), BasicBlock::new(4), false);
513 // `dest[i] = Clone::clone(src[beg])`;
514 // Goto #3 if ok, #5 if unwinding happens.
515 let dest_field = self.tcx.mk_place_index(dest, beg);
516 let src_field = self.tcx.mk_place_index(src, beg);
517 self.make_clone_call(dest_field, src_field, ty, BasicBlock::new(3), BasicBlock::new(5));
522 let statements = vec![self.make_statement(StatementKind::Assign(box (
526 Operand::Copy(Place::from(beg)),
527 Operand::Constant(self.make_usize(1)),
530 self.block(statements, TerminatorKind::Goto { target: BasicBlock::new(1) }, false);
534 self.block(vec![], TerminatorKind::Return, false);
538 // `let mut beg = 0;`
541 let beg = self.local_decls.push(LocalDecl::new(tcx.types.usize, span));
542 let init = self.make_statement(StatementKind::Assign(box (
544 Rvalue::Use(Operand::Constant(self.make_usize(0))),
546 self.block(vec![init], TerminatorKind::Goto { target: BasicBlock::new(6) }, true);
548 // BB #6 (cleanup): loop {
562 // `drop(dest[beg])`;
565 TerminatorKind::Drop {
566 place: self.tcx.mk_place_index(dest, beg),
567 target: BasicBlock::new(8),
576 let statement = self.make_statement(StatementKind::Assign(box (
580 Operand::Copy(Place::from(beg)),
581 Operand::Constant(self.make_usize(1)),
584 self.block(vec![statement], TerminatorKind::Goto { target: BasicBlock::new(6) }, true);
587 self.block(vec![], TerminatorKind::Resume, true);
590 fn tuple_like_shim<I>(&mut self, dest: Place<'tcx>, src: Place<'tcx>, tys: I)
592 I: Iterator<Item = Ty<'tcx>>,
594 let mut previous_field = None;
595 for (i, ity) in tys.enumerate() {
596 let field = Field::new(i);
597 let src_field = self.tcx.mk_place_field(src, field, ity);
599 let dest_field = self.tcx.mk_place_field(dest, field, ity);
601 // #(2i + 1) is the cleanup block for the previous clone operation
602 let cleanup_block = self.block_index_offset(1);
603 // #(2i + 2) is the next cloning block
604 // (or the Return terminator if this is the last block)
605 let next_block = self.block_index_offset(2);
608 // `dest.i = Clone::clone(&src.i);`
609 // Goto #(2i + 2) if ok, #(2i + 1) if unwinding happens.
610 self.make_clone_call(dest_field, src_field, ity, next_block, cleanup_block);
612 // BB #(2i + 1) (cleanup)
613 if let Some((previous_field, previous_cleanup)) = previous_field.take() {
614 // Drop previous field and goto previous cleanup block.
617 TerminatorKind::Drop {
618 place: previous_field,
619 target: previous_cleanup,
625 // Nothing to drop, just resume.
626 self.block(vec![], TerminatorKind::Resume, true);
629 previous_field = Some((dest_field, cleanup_block));
632 self.block(vec![], TerminatorKind::Return, false);
636 /// Builds a "call" shim for `instance`. The shim calls the function specified by `call_kind`,
637 /// first adjusting its first argument according to `rcvr_adjustment`.
638 fn build_call_shim<'tcx>(
640 instance: ty::InstanceDef<'tcx>,
641 rcvr_adjustment: Option<Adjustment>,
642 call_kind: CallKind<'tcx>,
645 "build_call_shim(instance={:?}, rcvr_adjustment={:?}, call_kind={:?})",
646 instance, rcvr_adjustment, call_kind
649 // `FnPtrShim` contains the fn pointer type that a call shim is being built for - this is used
650 // to substitute into the signature of the shim. It is not necessary for users of this
651 // MIR body to perform further substitutions (see `InstanceDef::has_polymorphic_mir_body`).
652 let (sig_substs, untuple_args) = if let ty::InstanceDef::FnPtrShim(_, ty) = instance {
653 let sig = tcx.erase_late_bound_regions(&ty.fn_sig(tcx));
655 let untuple_args = sig.inputs();
657 // Create substitutions for the `Self` and `Args` generic parameters of the shim body.
658 let arg_tup = tcx.mk_tup(untuple_args.iter());
659 let sig_substs = tcx.mk_substs_trait(ty, &[ty::subst::GenericArg::from(arg_tup)]);
661 (Some(sig_substs), Some(untuple_args))
666 let def_id = instance.def_id();
667 let sig = tcx.fn_sig(def_id);
668 let mut sig = tcx.erase_late_bound_regions(&sig);
670 assert_eq!(sig_substs.is_some(), !instance.has_polymorphic_mir_body());
671 if let Some(sig_substs) = sig_substs {
672 sig = sig.subst(tcx, sig_substs);
675 if let CallKind::Indirect(fnty) = call_kind {
676 // `sig` determines our local decls, and thus the callee type in the `Call` terminator. This
677 // can only be an `FnDef` or `FnPtr`, but currently will be `Self` since the types come from
678 // the implemented `FnX` trait.
680 // Apply the opposite adjustment to the MIR input.
681 let mut inputs_and_output = sig.inputs_and_output.to_vec();
683 // Initial signature is `fn(&? Self, Args) -> Self::Output` where `Args` is a tuple of the
684 // fn arguments. `Self` may be passed via (im)mutable reference or by-value.
685 assert_eq!(inputs_and_output.len(), 3);
687 // `Self` is always the original fn type `ty`. The MIR call terminator is only defined for
688 // `FnDef` and `FnPtr` callees, not the `Self` type param.
689 let self_arg = &mut inputs_and_output[0];
690 *self_arg = match rcvr_adjustment.unwrap() {
691 Adjustment::Identity => fnty,
692 Adjustment::Deref => tcx.mk_imm_ptr(fnty),
693 Adjustment::RefMut => tcx.mk_mut_ptr(fnty),
695 sig.inputs_and_output = tcx.intern_type_list(&inputs_and_output);
698 // FIXME(eddyb) avoid having this snippet both here and in
699 // `Instance::fn_sig` (introduce `InstanceDef::fn_sig`?).
700 if let ty::InstanceDef::VtableShim(..) = instance {
701 // Modify fn(self, ...) to fn(self: *mut Self, ...)
702 let mut inputs_and_output = sig.inputs_and_output.to_vec();
703 let self_arg = &mut inputs_and_output[0];
704 debug_assert!(tcx.generics_of(def_id).has_self && *self_arg == tcx.types.self_param);
705 *self_arg = tcx.mk_mut_ptr(*self_arg);
706 sig.inputs_and_output = tcx.intern_type_list(&inputs_and_output);
709 let span = tcx.def_span(def_id);
711 debug!("build_call_shim: sig={:?}", sig);
713 let mut local_decls = local_decls_for_sig(&sig, span);
714 let source_info = SourceInfo::outermost(span);
716 let rcvr_place = || {
717 assert!(rcvr_adjustment.is_some());
718 Place::from(Local::new(1 + 0))
720 let mut statements = vec![];
722 let rcvr = rcvr_adjustment.map(|rcvr_adjustment| match rcvr_adjustment {
723 Adjustment::Identity => Operand::Move(rcvr_place()),
724 Adjustment::Deref => Operand::Move(tcx.mk_place_deref(rcvr_place())),
725 Adjustment::RefMut => {
726 // let rcvr = &mut rcvr;
727 let ref_rcvr = local_decls.push(
730 tcx.lifetimes.re_erased,
731 ty::TypeAndMut { ty: sig.inputs()[0], mutbl: hir::Mutability::Mut },
737 let borrow_kind = BorrowKind::Mut { allow_two_phase_borrow: false };
738 statements.push(Statement {
740 kind: StatementKind::Assign(box (
741 Place::from(ref_rcvr),
742 Rvalue::Ref(tcx.lifetimes.re_erased, borrow_kind, rcvr_place()),
745 Operand::Move(Place::from(ref_rcvr))
749 let (callee, mut args) = match call_kind {
750 // `FnPtr` call has no receiver. Args are untupled below.
751 CallKind::Indirect(_) => (rcvr.unwrap(), vec![]),
753 // `FnDef` call with optional receiver.
754 CallKind::Direct(def_id) => {
755 let ty = tcx.type_of(def_id);
757 Operand::Constant(box Constant {
760 literal: ty::Const::zero_sized(tcx, ty),
762 rcvr.into_iter().collect::<Vec<_>>(),
767 let mut arg_range = 0..sig.inputs().len();
769 // Take the `self` ("receiver") argument out of the range (it's adjusted above).
770 if rcvr_adjustment.is_some() {
771 arg_range.start += 1;
774 // Take the last argument, if we need to untuple it (handled below).
775 if untuple_args.is_some() {
779 // Pass all of the non-special arguments directly.
780 args.extend(arg_range.map(|i| Operand::Move(Place::from(Local::new(1 + i)))));
782 // Untuple the last argument, if we have to.
783 if let Some(untuple_args) = untuple_args {
784 let tuple_arg = Local::new(1 + (sig.inputs().len() - 1));
785 args.extend(untuple_args.iter().enumerate().map(|(i, ity)| {
786 Operand::Move(tcx.mk_place_field(Place::from(tuple_arg), Field::new(i), *ity))
790 let n_blocks = if let Some(Adjustment::RefMut) = rcvr_adjustment { 5 } else { 2 };
791 let mut blocks = IndexVec::with_capacity(n_blocks);
792 let block = |blocks: &mut IndexVec<_, _>, statements, kind, is_cleanup| {
793 blocks.push(BasicBlockData {
795 terminator: Some(Terminator { source_info, kind }),
804 TerminatorKind::Call {
807 destination: Some((Place::return_place(), BasicBlock::new(1))),
808 cleanup: if let Some(Adjustment::RefMut) = rcvr_adjustment {
809 Some(BasicBlock::new(3))
819 if let Some(Adjustment::RefMut) = rcvr_adjustment {
820 // BB #1 - drop for Self
824 TerminatorKind::Drop { place: rcvr_place(), target: BasicBlock::new(2), unwind: None },
829 block(&mut blocks, vec![], TerminatorKind::Return, false);
830 if let Some(Adjustment::RefMut) = rcvr_adjustment {
831 // BB #3 - drop if closure panics
835 TerminatorKind::Drop { place: rcvr_place(), target: BasicBlock::new(4), unwind: None },
840 block(&mut blocks, vec![], TerminatorKind::Resume, true);
844 new_body(MirSource::from_instance(instance), blocks, local_decls, sig.inputs().len(), span);
846 if let Abi::RustCall = sig.abi {
847 body.spread_arg = Some(Local::new(sig.inputs().len()));
853 pub fn build_adt_ctor(tcx: TyCtxt<'_>, ctor_id: DefId) -> Body<'_> {
854 debug_assert!(tcx.is_constructor(ctor_id));
857 tcx.hir().span_if_local(ctor_id).unwrap_or_else(|| bug!("no span for ctor {:?}", ctor_id));
859 let param_env = tcx.param_env(ctor_id);
861 // Normalize the sig.
862 let sig = tcx.fn_sig(ctor_id).no_bound_vars().expect("LBR in ADT constructor signature");
863 let sig = tcx.normalize_erasing_regions(param_env, sig);
865 let (adt_def, substs) = match sig.output().kind() {
866 ty::Adt(adt_def, substs) => (adt_def, substs),
867 _ => bug!("unexpected type for ADT ctor {:?}", sig.output()),
870 debug!("build_ctor: ctor_id={:?} sig={:?}", ctor_id, sig);
872 let local_decls = local_decls_for_sig(&sig, span);
874 let source_info = SourceInfo::outermost(span);
876 let variant_index = if adt_def.is_enum() {
877 adt_def.variant_index_with_ctor_id(ctor_id)
882 // Generate the following MIR:
884 // (return as Variant).field0 = arg0;
885 // (return as Variant).field1 = arg1;
888 debug!("build_ctor: variant_index={:?}", variant_index);
890 let statements = expand_aggregate(
891 Place::return_place(),
892 adt_def.variants[variant_index].fields.iter().enumerate().map(|(idx, field_def)| {
893 (Operand::Move(Place::from(Local::new(idx + 1))), field_def.ty(tcx, substs))
895 AggregateKind::Adt(adt_def, variant_index, substs, None, None),
901 let start_block = BasicBlockData {
903 terminator: Some(Terminator { source_info, kind: TerminatorKind::Return }),
907 let source = MirSource::item(ctor_id);
910 IndexVec::from_elem_n(start_block, 1),
916 crate::util::dump_mir(tcx, None, "mir_map", &0, &body, |_, _| Ok(()));