diff options
Diffstat (limited to 'compiler/rustc_mir_transform/src/shim.rs')
| -rw-r--r-- | compiler/rustc_mir_transform/src/shim.rs | 790 |
1 files changed, 790 insertions, 0 deletions
diff --git a/compiler/rustc_mir_transform/src/shim.rs b/compiler/rustc_mir_transform/src/shim.rs new file mode 100644 index 000000000..3620e94be --- /dev/null +++ b/compiler/rustc_mir_transform/src/shim.rs @@ -0,0 +1,790 @@ +use rustc_hir as hir; +use rustc_hir::def_id::DefId; +use rustc_hir::lang_items::LangItem; +use rustc_middle::mir::*; +use rustc_middle::ty::query::Providers; +use rustc_middle::ty::subst::{InternalSubsts, Subst}; +use rustc_middle::ty::{self, EarlyBinder, Ty, TyCtxt}; +use rustc_target::abi::VariantIdx; + +use rustc_index::vec::{Idx, IndexVec}; + +use rustc_span::Span; +use rustc_target::spec::abi::Abi; + +use std::fmt; +use std::iter; + +use crate::util::expand_aggregate; +use crate::{ + abort_unwinding_calls, add_call_guards, add_moves_for_packed_drops, marker, pass_manager as pm, + remove_noop_landing_pads, simplify, +}; +use rustc_middle::mir::patch::MirPatch; +use rustc_mir_dataflow::elaborate_drops::{self, DropElaborator, DropFlagMode, DropStyle}; + +pub fn provide(providers: &mut Providers) { + providers.mir_shims = make_shim; +} + +fn make_shim<'tcx>(tcx: TyCtxt<'tcx>, instance: ty::InstanceDef<'tcx>) -> Body<'tcx> { + debug!("make_shim({:?})", instance); + + let mut result = match instance { + ty::InstanceDef::Item(..) => bug!("item {:?} passed to make_shim", instance), + ty::InstanceDef::VTableShim(def_id) => { + build_call_shim(tcx, instance, Some(Adjustment::Deref), CallKind::Direct(def_id)) + } + ty::InstanceDef::FnPtrShim(def_id, ty) => { + let trait_ = tcx.trait_of_item(def_id).unwrap(); + let adjustment = match tcx.fn_trait_kind_from_lang_item(trait_) { + Some(ty::ClosureKind::FnOnce) => Adjustment::Identity, + Some(ty::ClosureKind::FnMut | ty::ClosureKind::Fn) => Adjustment::Deref, + None => bug!("fn pointer {:?} is not an fn", ty), + }; + + build_call_shim(tcx, instance, Some(adjustment), CallKind::Indirect(ty)) + } + // We are generating a call back to our def-id, which the + // codegen backend knows to turn to an actual call, be it + // a virtual call, or a direct call to a function for which + // indirect calls must be codegen'd differently than direct ones + // (such as `#[track_caller]`). + ty::InstanceDef::ReifyShim(def_id) => { + build_call_shim(tcx, instance, None, CallKind::Direct(def_id)) + } + ty::InstanceDef::ClosureOnceShim { call_once: _, track_caller: _ } => { + let fn_mut = tcx.require_lang_item(LangItem::FnMut, None); + let call_mut = tcx + .associated_items(fn_mut) + .in_definition_order() + .find(|it| it.kind == ty::AssocKind::Fn) + .unwrap() + .def_id; + + build_call_shim(tcx, instance, Some(Adjustment::RefMut), CallKind::Direct(call_mut)) + } + + ty::InstanceDef::DropGlue(def_id, ty) => { + // FIXME(#91576): Drop shims for generators aren't subject to the MIR passes at the end + // of this function. Is this intentional? + if let Some(ty::Generator(gen_def_id, substs, _)) = ty.map(Ty::kind) { + let body = tcx.optimized_mir(*gen_def_id).generator_drop().unwrap(); + let body = EarlyBinder(body.clone()).subst(tcx, substs); + debug!("make_shim({:?}) = {:?}", instance, body); + return body; + } + + build_drop_shim(tcx, def_id, ty) + } + ty::InstanceDef::CloneShim(def_id, ty) => build_clone_shim(tcx, def_id, ty), + ty::InstanceDef::Virtual(..) => { + bug!("InstanceDef::Virtual ({:?}) is for direct calls only", instance) + } + ty::InstanceDef::Intrinsic(_) => { + bug!("creating shims from intrinsics ({:?}) is unsupported", instance) + } + }; + debug!("make_shim({:?}) = untransformed {:?}", instance, result); + + pm::run_passes( + tcx, + &mut result, + &[ + &add_moves_for_packed_drops::AddMovesForPackedDrops, + &remove_noop_landing_pads::RemoveNoopLandingPads, + &simplify::SimplifyCfg::new("make_shim"), + &add_call_guards::CriticalCallEdges, + &abort_unwinding_calls::AbortUnwindingCalls, + &marker::PhaseChange(MirPhase::Const), + ], + ); + + debug!("make_shim({:?}) = {:?}", instance, result); + + result +} + +#[derive(Copy, Clone, Debug, PartialEq)] +enum Adjustment { + /// Pass the receiver as-is. + Identity, + + /// We get passed `&[mut] self` and call the target with `*self`. + /// + /// This either copies `self` (if `Self: Copy`, eg. for function items), or moves out of it + /// (for `VTableShim`, which effectively is passed `&own Self`). + Deref, + + /// We get passed `self: Self` and call the target with `&mut self`. + /// + /// In this case we need to ensure that the `Self` is dropped after the call, as the callee + /// won't do it for us. + RefMut, +} + +#[derive(Copy, Clone, Debug, PartialEq)] +enum CallKind<'tcx> { + /// Call the `FnPtr` that was passed as the receiver. + Indirect(Ty<'tcx>), + + /// Call a known `FnDef`. + Direct(DefId), +} + +fn local_decls_for_sig<'tcx>( + sig: &ty::FnSig<'tcx>, + span: Span, +) -> IndexVec<Local, LocalDecl<'tcx>> { + iter::once(LocalDecl::new(sig.output(), span)) + .chain(sig.inputs().iter().map(|ity| LocalDecl::new(*ity, span).immutable())) + .collect() +} + +fn build_drop_shim<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, ty: Option<Ty<'tcx>>) -> Body<'tcx> { + debug!("build_drop_shim(def_id={:?}, ty={:?})", def_id, ty); + + assert!(!matches!(ty, Some(ty) if ty.is_generator())); + + let substs = if let Some(ty) = ty { + tcx.intern_substs(&[ty.into()]) + } else { + InternalSubsts::identity_for_item(tcx, def_id) + }; + let sig = tcx.bound_fn_sig(def_id).subst(tcx, substs); + let sig = tcx.erase_late_bound_regions(sig); + let span = tcx.def_span(def_id); + + let source_info = SourceInfo::outermost(span); + + let return_block = BasicBlock::new(1); + let mut blocks = IndexVec::with_capacity(2); + let block = |blocks: &mut IndexVec<_, _>, kind| { + blocks.push(BasicBlockData { + statements: vec![], + terminator: Some(Terminator { source_info, kind }), + is_cleanup: false, + }) + }; + block(&mut blocks, TerminatorKind::Goto { target: return_block }); + block(&mut blocks, TerminatorKind::Return); + + let source = MirSource::from_instance(ty::InstanceDef::DropGlue(def_id, ty)); + let mut body = + new_body(source, blocks, local_decls_for_sig(&sig, span), sig.inputs().len(), span); + + if ty.is_some() { + // The first argument (index 0), but add 1 for the return value. + let dropee_ptr = Place::from(Local::new(1 + 0)); + if tcx.sess.opts.unstable_opts.mir_emit_retag { + // Function arguments should be retagged, and we make this one raw. + body.basic_blocks_mut()[START_BLOCK].statements.insert( + 0, + Statement { + source_info, + kind: StatementKind::Retag(RetagKind::Raw, Box::new(dropee_ptr)), + }, + ); + } + let patch = { + let param_env = tcx.param_env_reveal_all_normalized(def_id); + let mut elaborator = + DropShimElaborator { body: &body, patch: MirPatch::new(&body), tcx, param_env }; + let dropee = tcx.mk_place_deref(dropee_ptr); + let resume_block = elaborator.patch.resume_block(); + elaborate_drops::elaborate_drop( + &mut elaborator, + source_info, + dropee, + (), + return_block, + elaborate_drops::Unwind::To(resume_block), + START_BLOCK, + ); + elaborator.patch + }; + patch.apply(&mut body); + } + + body +} + +fn new_body<'tcx>( + source: MirSource<'tcx>, + basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>, + local_decls: IndexVec<Local, LocalDecl<'tcx>>, + arg_count: usize, + span: Span, +) -> Body<'tcx> { + Body::new( + source, + basic_blocks, + IndexVec::from_elem_n( + SourceScopeData { + span, + parent_scope: None, + inlined: None, + inlined_parent_scope: None, + local_data: ClearCrossCrate::Clear, + }, + 1, + ), + local_decls, + IndexVec::new(), + arg_count, + vec![], + span, + None, + // FIXME(compiler-errors): is this correct? + None, + ) +} + +pub struct DropShimElaborator<'a, 'tcx> { + pub body: &'a Body<'tcx>, + pub patch: MirPatch<'tcx>, + pub tcx: TyCtxt<'tcx>, + pub param_env: ty::ParamEnv<'tcx>, +} + +impl fmt::Debug for DropShimElaborator<'_, '_> { + fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> { + Ok(()) + } +} + +impl<'a, 'tcx> DropElaborator<'a, 'tcx> for DropShimElaborator<'a, 'tcx> { + type Path = (); + + fn patch(&mut self) -> &mut MirPatch<'tcx> { + &mut self.patch + } + fn body(&self) -> &'a Body<'tcx> { + self.body + } + fn tcx(&self) -> TyCtxt<'tcx> { + self.tcx + } + fn param_env(&self) -> ty::ParamEnv<'tcx> { + self.param_env + } + + fn drop_style(&self, _path: Self::Path, mode: DropFlagMode) -> DropStyle { + match mode { + DropFlagMode::Shallow => { + // Drops for the contained fields are "shallow" and "static" - they will simply call + // the field's own drop glue. + DropStyle::Static + } + DropFlagMode::Deep => { + // The top-level drop is "deep" and "open" - it will be elaborated to a drop ladder + // dropping each field contained in the value. + DropStyle::Open + } + } + } + + fn get_drop_flag(&mut self, _path: Self::Path) -> Option<Operand<'tcx>> { + None + } + + fn clear_drop_flag(&mut self, _location: Location, _path: Self::Path, _mode: DropFlagMode) {} + + fn field_subpath(&self, _path: Self::Path, _field: Field) -> Option<Self::Path> { + None + } + fn deref_subpath(&self, _path: Self::Path) -> Option<Self::Path> { + None + } + fn downcast_subpath(&self, _path: Self::Path, _variant: VariantIdx) -> Option<Self::Path> { + Some(()) + } + fn array_subpath(&self, _path: Self::Path, _index: u64, _size: u64) -> Option<Self::Path> { + None + } +} + +/// Builds a `Clone::clone` shim for `self_ty`. Here, `def_id` is `Clone::clone`. +fn build_clone_shim<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, self_ty: Ty<'tcx>) -> Body<'tcx> { + debug!("build_clone_shim(def_id={:?})", def_id); + + let param_env = tcx.param_env(def_id); + + let mut builder = CloneShimBuilder::new(tcx, def_id, self_ty); + let is_copy = self_ty.is_copy_modulo_regions(tcx.at(builder.span), param_env); + + let dest = Place::return_place(); + let src = tcx.mk_place_deref(Place::from(Local::new(1 + 0))); + + match self_ty.kind() { + _ if is_copy => builder.copy_shim(), + ty::Closure(_, substs) => { + builder.tuple_like_shim(dest, src, substs.as_closure().upvar_tys()) + } + ty::Tuple(..) => builder.tuple_like_shim(dest, src, self_ty.tuple_fields()), + _ => bug!("clone shim for `{:?}` which is not `Copy` and is not an aggregate", self_ty), + }; + + builder.into_mir() +} + +struct CloneShimBuilder<'tcx> { + tcx: TyCtxt<'tcx>, + def_id: DefId, + local_decls: IndexVec<Local, LocalDecl<'tcx>>, + blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>, + span: Span, + sig: ty::FnSig<'tcx>, +} + +impl<'tcx> CloneShimBuilder<'tcx> { + fn new(tcx: TyCtxt<'tcx>, def_id: DefId, self_ty: Ty<'tcx>) -> Self { + // we must subst the self_ty because it's + // otherwise going to be TySelf and we can't index + // or access fields of a Place of type TySelf. + let substs = tcx.mk_substs_trait(self_ty, &[]); + let sig = tcx.bound_fn_sig(def_id).subst(tcx, substs); + let sig = tcx.erase_late_bound_regions(sig); + let span = tcx.def_span(def_id); + + CloneShimBuilder { + tcx, + def_id, + local_decls: local_decls_for_sig(&sig, span), + blocks: IndexVec::new(), + span, + sig, + } + } + + fn into_mir(self) -> Body<'tcx> { + let source = MirSource::from_instance(ty::InstanceDef::CloneShim( + self.def_id, + self.sig.inputs_and_output[0], + )); + new_body(source, self.blocks, self.local_decls, self.sig.inputs().len(), self.span) + } + + fn source_info(&self) -> SourceInfo { + SourceInfo::outermost(self.span) + } + + fn block( + &mut self, + statements: Vec<Statement<'tcx>>, + kind: TerminatorKind<'tcx>, + is_cleanup: bool, + ) -> BasicBlock { + let source_info = self.source_info(); + self.blocks.push(BasicBlockData { + statements, + terminator: Some(Terminator { source_info, kind }), + is_cleanup, + }) + } + + /// Gives the index of an upcoming BasicBlock, with an offset. + /// offset=0 will give you the index of the next BasicBlock, + /// offset=1 will give the index of the next-to-next block, + /// offset=-1 will give you the index of the last-created block + fn block_index_offset(&mut self, offset: usize) -> BasicBlock { + BasicBlock::new(self.blocks.len() + offset) + } + + fn make_statement(&self, kind: StatementKind<'tcx>) -> Statement<'tcx> { + Statement { source_info: self.source_info(), kind } + } + + fn copy_shim(&mut self) { + let rcvr = self.tcx.mk_place_deref(Place::from(Local::new(1 + 0))); + let ret_statement = self.make_statement(StatementKind::Assign(Box::new(( + Place::return_place(), + Rvalue::Use(Operand::Copy(rcvr)), + )))); + self.block(vec![ret_statement], TerminatorKind::Return, false); + } + + fn make_place(&mut self, mutability: Mutability, ty: Ty<'tcx>) -> Place<'tcx> { + let span = self.span; + let mut local = LocalDecl::new(ty, span); + if mutability == Mutability::Not { + local = local.immutable(); + } + Place::from(self.local_decls.push(local)) + } + + fn make_clone_call( + &mut self, + dest: Place<'tcx>, + src: Place<'tcx>, + ty: Ty<'tcx>, + next: BasicBlock, + cleanup: BasicBlock, + ) { + let tcx = self.tcx; + + let substs = tcx.mk_substs_trait(ty, &[]); + + // `func == Clone::clone(&ty) -> ty` + let func_ty = tcx.mk_fn_def(self.def_id, substs); + let func = Operand::Constant(Box::new(Constant { + span: self.span, + user_ty: None, + literal: ConstantKind::zero_sized(func_ty), + })); + + let ref_loc = self.make_place( + Mutability::Not, + tcx.mk_ref(tcx.lifetimes.re_erased, ty::TypeAndMut { ty, mutbl: hir::Mutability::Not }), + ); + + // `let ref_loc: &ty = &src;` + let statement = self.make_statement(StatementKind::Assign(Box::new(( + ref_loc, + Rvalue::Ref(tcx.lifetimes.re_erased, BorrowKind::Shared, src), + )))); + + // `let loc = Clone::clone(ref_loc);` + self.block( + vec![statement], + TerminatorKind::Call { + func, + args: vec![Operand::Move(ref_loc)], + destination: dest, + target: Some(next), + cleanup: Some(cleanup), + from_hir_call: true, + fn_span: self.span, + }, + false, + ); + } + + fn tuple_like_shim<I>(&mut self, dest: Place<'tcx>, src: Place<'tcx>, tys: I) + where + I: IntoIterator<Item = Ty<'tcx>>, + { + let mut previous_field = None; + for (i, ity) in tys.into_iter().enumerate() { + let field = Field::new(i); + let src_field = self.tcx.mk_place_field(src, field, ity); + + let dest_field = self.tcx.mk_place_field(dest, field, ity); + + // #(2i + 1) is the cleanup block for the previous clone operation + let cleanup_block = self.block_index_offset(1); + // #(2i + 2) is the next cloning block + // (or the Return terminator if this is the last block) + let next_block = self.block_index_offset(2); + + // BB #(2i) + // `dest.i = Clone::clone(&src.i);` + // Goto #(2i + 2) if ok, #(2i + 1) if unwinding happens. + self.make_clone_call(dest_field, src_field, ity, next_block, cleanup_block); + + // BB #(2i + 1) (cleanup) + if let Some((previous_field, previous_cleanup)) = previous_field.take() { + // Drop previous field and goto previous cleanup block. + self.block( + vec![], + TerminatorKind::Drop { + place: previous_field, + target: previous_cleanup, + unwind: None, + }, + true, + ); + } else { + // Nothing to drop, just resume. + self.block(vec![], TerminatorKind::Resume, true); + } + + previous_field = Some((dest_field, cleanup_block)); + } + + self.block(vec![], TerminatorKind::Return, false); + } +} + +/// Builds a "call" shim for `instance`. The shim calls the function specified by `call_kind`, +/// first adjusting its first argument according to `rcvr_adjustment`. +fn build_call_shim<'tcx>( + tcx: TyCtxt<'tcx>, + instance: ty::InstanceDef<'tcx>, + rcvr_adjustment: Option<Adjustment>, + call_kind: CallKind<'tcx>, +) -> Body<'tcx> { + debug!( + "build_call_shim(instance={:?}, rcvr_adjustment={:?}, call_kind={:?})", + instance, rcvr_adjustment, call_kind + ); + + // `FnPtrShim` contains the fn pointer type that a call shim is being built for - this is used + // to substitute into the signature of the shim. It is not necessary for users of this + // MIR body to perform further substitutions (see `InstanceDef::has_polymorphic_mir_body`). + let (sig_substs, untuple_args) = if let ty::InstanceDef::FnPtrShim(_, ty) = instance { + let sig = tcx.erase_late_bound_regions(ty.fn_sig(tcx)); + + let untuple_args = sig.inputs(); + + // Create substitutions for the `Self` and `Args` generic parameters of the shim body. + let arg_tup = tcx.mk_tup(untuple_args.iter()); + let sig_substs = tcx.mk_substs_trait(ty, &[ty::subst::GenericArg::from(arg_tup)]); + + (Some(sig_substs), Some(untuple_args)) + } else { + (None, None) + }; + + let def_id = instance.def_id(); + let sig = tcx.bound_fn_sig(def_id); + let sig = sig.map_bound(|sig| tcx.erase_late_bound_regions(sig)); + + assert_eq!(sig_substs.is_some(), !instance.has_polymorphic_mir_body()); + let mut sig = + if let Some(sig_substs) = sig_substs { sig.subst(tcx, sig_substs) } else { sig.0 }; + + if let CallKind::Indirect(fnty) = call_kind { + // `sig` determines our local decls, and thus the callee type in the `Call` terminator. This + // can only be an `FnDef` or `FnPtr`, but currently will be `Self` since the types come from + // the implemented `FnX` trait. + + // Apply the opposite adjustment to the MIR input. + let mut inputs_and_output = sig.inputs_and_output.to_vec(); + + // Initial signature is `fn(&? Self, Args) -> Self::Output` where `Args` is a tuple of the + // fn arguments. `Self` may be passed via (im)mutable reference or by-value. + assert_eq!(inputs_and_output.len(), 3); + + // `Self` is always the original fn type `ty`. The MIR call terminator is only defined for + // `FnDef` and `FnPtr` callees, not the `Self` type param. + let self_arg = &mut inputs_and_output[0]; + *self_arg = match rcvr_adjustment.unwrap() { + Adjustment::Identity => fnty, + Adjustment::Deref => tcx.mk_imm_ptr(fnty), + Adjustment::RefMut => tcx.mk_mut_ptr(fnty), + }; + sig.inputs_and_output = tcx.intern_type_list(&inputs_and_output); + } + + // FIXME(eddyb) avoid having this snippet both here and in + // `Instance::fn_sig` (introduce `InstanceDef::fn_sig`?). + if let ty::InstanceDef::VTableShim(..) = instance { + // Modify fn(self, ...) to fn(self: *mut Self, ...) + let mut inputs_and_output = sig.inputs_and_output.to_vec(); + let self_arg = &mut inputs_and_output[0]; + debug_assert!(tcx.generics_of(def_id).has_self && *self_arg == tcx.types.self_param); + *self_arg = tcx.mk_mut_ptr(*self_arg); + sig.inputs_and_output = tcx.intern_type_list(&inputs_and_output); + } + + let span = tcx.def_span(def_id); + + debug!("build_call_shim: sig={:?}", sig); + + let mut local_decls = local_decls_for_sig(&sig, span); + let source_info = SourceInfo::outermost(span); + + let rcvr_place = || { + assert!(rcvr_adjustment.is_some()); + Place::from(Local::new(1 + 0)) + }; + let mut statements = vec![]; + + let rcvr = rcvr_adjustment.map(|rcvr_adjustment| match rcvr_adjustment { + Adjustment::Identity => Operand::Move(rcvr_place()), + Adjustment::Deref => Operand::Move(tcx.mk_place_deref(rcvr_place())), + Adjustment::RefMut => { + // let rcvr = &mut rcvr; + let ref_rcvr = local_decls.push( + LocalDecl::new( + tcx.mk_ref( + tcx.lifetimes.re_erased, + ty::TypeAndMut { ty: sig.inputs()[0], mutbl: hir::Mutability::Mut }, + ), + span, + ) + .immutable(), + ); + let borrow_kind = BorrowKind::Mut { allow_two_phase_borrow: false }; + statements.push(Statement { + source_info, + kind: StatementKind::Assign(Box::new(( + Place::from(ref_rcvr), + Rvalue::Ref(tcx.lifetimes.re_erased, borrow_kind, rcvr_place()), + ))), + }); + Operand::Move(Place::from(ref_rcvr)) + } + }); + + let (callee, mut args) = match call_kind { + // `FnPtr` call has no receiver. Args are untupled below. + CallKind::Indirect(_) => (rcvr.unwrap(), vec![]), + + // `FnDef` call with optional receiver. + CallKind::Direct(def_id) => { + let ty = tcx.type_of(def_id); + ( + Operand::Constant(Box::new(Constant { + span, + user_ty: None, + literal: ConstantKind::zero_sized(ty), + })), + rcvr.into_iter().collect::<Vec<_>>(), + ) + } + }; + + let mut arg_range = 0..sig.inputs().len(); + + // Take the `self` ("receiver") argument out of the range (it's adjusted above). + if rcvr_adjustment.is_some() { + arg_range.start += 1; + } + + // Take the last argument, if we need to untuple it (handled below). + if untuple_args.is_some() { + arg_range.end -= 1; + } + + // Pass all of the non-special arguments directly. + args.extend(arg_range.map(|i| Operand::Move(Place::from(Local::new(1 + i))))); + + // Untuple the last argument, if we have to. + if let Some(untuple_args) = untuple_args { + let tuple_arg = Local::new(1 + (sig.inputs().len() - 1)); + args.extend(untuple_args.iter().enumerate().map(|(i, ity)| { + Operand::Move(tcx.mk_place_field(Place::from(tuple_arg), Field::new(i), *ity)) + })); + } + + let n_blocks = if let Some(Adjustment::RefMut) = rcvr_adjustment { 5 } else { 2 }; + let mut blocks = IndexVec::with_capacity(n_blocks); + let block = |blocks: &mut IndexVec<_, _>, statements, kind, is_cleanup| { + blocks.push(BasicBlockData { + statements, + terminator: Some(Terminator { source_info, kind }), + is_cleanup, + }) + }; + + // BB #0 + block( + &mut blocks, + statements, + TerminatorKind::Call { + func: callee, + args, + destination: Place::return_place(), + target: Some(BasicBlock::new(1)), + cleanup: if let Some(Adjustment::RefMut) = rcvr_adjustment { + Some(BasicBlock::new(3)) + } else { + None + }, + from_hir_call: true, + fn_span: span, + }, + false, + ); + + if let Some(Adjustment::RefMut) = rcvr_adjustment { + // BB #1 - drop for Self + block( + &mut blocks, + vec![], + TerminatorKind::Drop { place: rcvr_place(), target: BasicBlock::new(2), unwind: None }, + false, + ); + } + // BB #1/#2 - return + block(&mut blocks, vec![], TerminatorKind::Return, false); + if let Some(Adjustment::RefMut) = rcvr_adjustment { + // BB #3 - drop if closure panics + block( + &mut blocks, + vec![], + TerminatorKind::Drop { place: rcvr_place(), target: BasicBlock::new(4), unwind: None }, + true, + ); + + // BB #4 - resume + block(&mut blocks, vec![], TerminatorKind::Resume, true); + } + + let mut body = + new_body(MirSource::from_instance(instance), blocks, local_decls, sig.inputs().len(), span); + + if let Abi::RustCall = sig.abi { + body.spread_arg = Some(Local::new(sig.inputs().len())); + } + + body +} + +pub fn build_adt_ctor(tcx: TyCtxt<'_>, ctor_id: DefId) -> Body<'_> { + debug_assert!(tcx.is_constructor(ctor_id)); + + let param_env = tcx.param_env(ctor_id); + + // Normalize the sig. + let sig = tcx.fn_sig(ctor_id).no_bound_vars().expect("LBR in ADT constructor signature"); + let sig = tcx.normalize_erasing_regions(param_env, sig); + + let ty::Adt(adt_def, substs) = sig.output().kind() else { + bug!("unexpected type for ADT ctor {:?}", sig.output()); + }; + + debug!("build_ctor: ctor_id={:?} sig={:?}", ctor_id, sig); + + let span = tcx.def_span(ctor_id); + + let local_decls = local_decls_for_sig(&sig, span); + + let source_info = SourceInfo::outermost(span); + + let variant_index = if adt_def.is_enum() { + adt_def.variant_index_with_ctor_id(ctor_id) + } else { + VariantIdx::new(0) + }; + + // Generate the following MIR: + // + // (return as Variant).field0 = arg0; + // (return as Variant).field1 = arg1; + // + // return; + debug!("build_ctor: variant_index={:?}", variant_index); + + let statements = expand_aggregate( + Place::return_place(), + adt_def.variant(variant_index).fields.iter().enumerate().map(|(idx, field_def)| { + (Operand::Move(Place::from(Local::new(idx + 1))), field_def.ty(tcx, substs)) + }), + AggregateKind::Adt(adt_def.did(), variant_index, substs, None, None), + source_info, + tcx, + ) + .collect(); + + let start_block = BasicBlockData { + statements, + terminator: Some(Terminator { source_info, kind: TerminatorKind::Return }), + is_cleanup: false, + }; + + let source = MirSource::item(ctor_id); + let body = new_body( + source, + IndexVec::from_elem_n(start_block, 1), + local_decls, + sig.inputs().len(), + span, + ); + + rustc_middle::mir::dump_mir(tcx, None, "mir_map", &0, &body, |_, _| Ok(())); + + body +} |