| use rustc::hir; |
| use rustc::hir::def_id::DefId; |
| use rustc::mir::*; |
| use rustc::ty::{self, Ty, TyCtxt}; |
| use rustc::ty::layout::VariantIdx; |
| use rustc::ty::subst::{Subst, InternalSubsts}; |
| use rustc::ty::query::Providers; |
| |
| use rustc_index::vec::{IndexVec, Idx}; |
| |
| use rustc_target::spec::abi::Abi; |
| use syntax_pos::{Span, sym}; |
| |
| use std::fmt; |
| use std::iter; |
| |
| use crate::transform::{ |
| add_moves_for_packed_drops, add_call_guards, |
| remove_noop_landing_pads, no_landing_pads, simplify, run_passes |
| }; |
| use crate::util::elaborate_drops::{self, DropElaborator, DropStyle, DropFlagMode}; |
| use crate::util::patch::MirPatch; |
| use crate::util::expand_aggregate; |
| |
| pub fn provide(providers: &mut Providers<'_>) { |
| providers.mir_shims = make_shim; |
| } |
| |
| fn make_shim<'tcx>(tcx: TyCtxt<'tcx>, instance: ty::InstanceDef<'tcx>) -> &'tcx BodyCache<'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, |
| Adjustment::DerefMove, |
| CallKind::Direct(def_id), |
| None, |
| ) |
| } |
| ty::InstanceDef::FnPtrShim(def_id, ty) => { |
| let trait_ = tcx.trait_of_item(def_id).unwrap(); |
| let adjustment = match tcx.lang_items().fn_trait_kind(trait_) { |
| Some(ty::ClosureKind::FnOnce) => Adjustment::Identity, |
| Some(ty::ClosureKind::FnMut) | |
| Some(ty::ClosureKind::Fn) => Adjustment::Deref, |
| None => bug!("fn pointer {:?} is not an fn", ty) |
| }; |
| // HACK: we need the "real" argument types for the MIR, |
| // but because our substs are (Self, Args), where Args |
| // is a tuple, we must include the *concrete* argument |
| // types in the MIR. They will be substituted again with |
| // the param-substs, but because they are concrete, this |
| // will not do any harm. |
| let sig = tcx.erase_late_bound_regions(&ty.fn_sig(tcx)); |
| let arg_tys = sig.inputs(); |
| |
| build_call_shim( |
| tcx, |
| instance, |
| adjustment, |
| CallKind::Indirect, |
| Some(arg_tys) |
| ) |
| } |
| // 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, |
| Adjustment::Identity, |
| CallKind::Direct(def_id), |
| None |
| ) |
| } |
| ty::InstanceDef::ClosureOnceShim { call_once: _ } => { |
| let fn_mut = tcx.lang_items().fn_mut_trait().unwrap(); |
| let call_mut = tcx |
| .associated_items(fn_mut) |
| .find(|it| it.kind == ty::AssocKind::Method) |
| .unwrap().def_id; |
| |
| build_call_shim( |
| tcx, |
| instance, |
| Adjustment::RefMut, |
| CallKind::Direct(call_mut), |
| None |
| ) |
| } |
| ty::InstanceDef::DropGlue(def_id, ty) => { |
| build_drop_shim(tcx, def_id, ty) |
| } |
| ty::InstanceDef::CloneShim(def_id, ty) => { |
| let name = tcx.item_name(def_id); |
| if name == sym::clone { |
| build_clone_shim(tcx, def_id, ty) |
| } else if name == sym::clone_from { |
| debug!("make_shim({:?}: using default trait implementation", instance); |
| return tcx.optimized_mir(def_id); |
| } else { |
| bug!("builtin clone shim {:?} not supported", instance) |
| } |
| } |
| 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); |
| |
| run_passes(tcx, &mut result, instance, None, MirPhase::Const, &[ |
| &add_moves_for_packed_drops::AddMovesForPackedDrops, |
| &no_landing_pads::NoLandingPads::new(tcx), |
| &remove_noop_landing_pads::RemoveNoopLandingPads, |
| &simplify::SimplifyCfg::new("make_shim"), |
| &add_call_guards::CriticalCallEdges, |
| ]); |
| |
| debug!("make_shim({:?}) = {:?}", instance, result); |
| |
| result.ensure_predecessors(); |
| tcx.arena.alloc(result) |
| } |
| |
| #[derive(Copy, Clone, Debug, PartialEq)] |
| enum Adjustment { |
| Identity, |
| Deref, |
| DerefMove, |
| RefMut, |
| } |
| |
| #[derive(Copy, Clone, Debug, PartialEq)] |
| enum CallKind { |
| Indirect, |
| Direct(DefId), |
| } |
| |
| fn temp_decl(mutability: Mutability, ty: Ty<'_>, span: Span) -> LocalDecl<'_> { |
| let source_info = SourceInfo { scope: OUTERMOST_SOURCE_SCOPE, span }; |
| LocalDecl { |
| mutability, |
| ty, |
| user_ty: UserTypeProjections::none(), |
| source_info, |
| internal: false, |
| local_info: LocalInfo::Other, |
| is_block_tail: None, |
| } |
| } |
| |
| fn local_decls_for_sig<'tcx>(sig: &ty::FnSig<'tcx>, span: Span) |
| -> IndexVec<Local, LocalDecl<'tcx>> |
| { |
| iter::once(temp_decl(Mutability::Mut, sig.output(), span)) |
| .chain(sig.inputs().iter().map( |
| |ity| temp_decl(Mutability::Not, ity, span))) |
| .collect() |
| } |
| |
| fn build_drop_shim<'tcx>( |
| tcx: TyCtxt<'tcx>, def_id: DefId, ty: Option<Ty<'tcx>> |
| ) -> BodyCache<'tcx> { |
| debug!("build_drop_shim(def_id={:?}, ty={:?})", def_id, ty); |
| |
| // Check if this is a generator, if so, return the drop glue for it |
| if let Some(&ty::TyS { kind: ty::Generator(gen_def_id, substs, _), .. }) = ty { |
| let body = &**tcx.optimized_mir(gen_def_id).generator_drop.as_ref().unwrap(); |
| return body.subst(tcx, substs); |
| } |
| |
| let substs = if let Some(ty) = ty { |
| tcx.intern_substs(&[ty.into()]) |
| } else { |
| InternalSubsts::identity_for_item(tcx, def_id) |
| }; |
| let sig = tcx.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 { span, scope: OUTERMOST_SOURCE_SCOPE }; |
| |
| 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 body = new_body( |
| blocks, |
| local_decls_for_sig(&sig, span), |
| sig.inputs().len(), |
| span); |
| |
| let mut body = BodyCache::new(body); |
| |
| if let Some(..) = ty { |
| // 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.debugging_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(dropee_ptr.clone())), |
| }); |
| } |
| let patch = { |
| let param_env = tcx.param_env(def_id).with_reveal_all(); |
| 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>( |
| basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>, |
| local_decls: IndexVec<Local, LocalDecl<'tcx>>, |
| arg_count: usize, |
| span: Span, |
| ) -> Body<'tcx> { |
| Body::new( |
| basic_blocks, |
| IndexVec::from_elem_n( |
| SourceScopeData { span, parent_scope: None, local_data: ClearCrossCrate::Clear }, |
| 1, |
| ), |
| local_decls, |
| IndexVec::new(), |
| arg_count, |
| vec![], |
| span, |
| vec![], |
| 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<'a, 'tcx> fmt::Debug for DropShimElaborator<'a, 'tcx> { |
| 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 { |
| if let DropFlagMode::Shallow = mode { |
| DropStyle::Static |
| } else { |
| 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: u32, _size: u32) -> 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>) -> BodyCache<'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, param_env, builder.span); |
| |
| 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::Array(ty, len) => { |
| let len = len.eval_usize(tcx, param_env); |
| builder.array_shim(dest, src, ty, len) |
| } |
| ty::Closure(def_id, substs) => { |
| builder.tuple_like_shim( |
| dest, src, |
| substs.as_closure().upvar_tys(def_id, tcx) |
| ) |
| } |
| 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) |
| } |
| }; |
| |
| BodyCache::new(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 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.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> { |
| new_body( |
| self.blocks, |
| self.local_decls, |
| self.sig.inputs().len(), |
| self.span, |
| ) |
| } |
| |
| fn source_info(&self) -> SourceInfo { |
| SourceInfo { span: self.span, scope: OUTERMOST_SOURCE_SCOPE } |
| } |
| |
| 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( |
| 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; |
| Place::from(self.local_decls.push(temp_decl(mutability, ty, span))) |
| } |
| |
| 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 Constant { |
| span: self.span, |
| user_ty: None, |
| literal: ty::Const::zero_sized(tcx, func_ty), |
| }); |
| |
| let ref_loc = self.make_place( |
| Mutability::Not, |
| tcx.mk_ref(tcx.lifetimes.re_erased, ty::TypeAndMut { |
| ty, |
| mutbl: hir::Mutability::Immutable, |
| }) |
| ); |
| |
| // `let ref_loc: &ty = &src;` |
| let statement = self.make_statement( |
| StatementKind::Assign( |
| box( |
| ref_loc.clone(), |
| 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: Some((dest, next)), |
| cleanup: Some(cleanup), |
| from_hir_call: true, |
| }, false); |
| } |
| |
| fn loop_header( |
| &mut self, |
| beg: Place<'tcx>, |
| end: Place<'tcx>, |
| loop_body: BasicBlock, |
| loop_end: BasicBlock, |
| is_cleanup: bool |
| ) { |
| let tcx = self.tcx; |
| |
| let cond = self.make_place(Mutability::Mut, tcx.types.bool); |
| let compute_cond = self.make_statement( |
| StatementKind::Assign( |
| box( |
| cond.clone(), |
| Rvalue::BinaryOp(BinOp::Ne, Operand::Copy(end), Operand::Copy(beg)) |
| ) |
| ) |
| ); |
| |
| // `if end != beg { goto loop_body; } else { goto loop_end; }` |
| self.block( |
| vec![compute_cond], |
| TerminatorKind::if_(tcx, Operand::Move(cond), loop_body, loop_end), |
| is_cleanup |
| ); |
| } |
| |
| fn make_usize(&self, value: u64) -> Box<Constant<'tcx>> { |
| box Constant { |
| span: self.span, |
| user_ty: None, |
| literal: ty::Const::from_usize(self.tcx, value), |
| } |
| } |
| |
| fn array_shim(&mut self, dest: Place<'tcx>, src: Place<'tcx>, ty: Ty<'tcx>, len: u64) { |
| let tcx = self.tcx; |
| let span = self.span; |
| |
| let beg = self.local_decls.push(temp_decl(Mutability::Mut, tcx.types.usize, span)); |
| let end = self.make_place(Mutability::Not, tcx.types.usize); |
| |
| // BB #0 |
| // `let mut beg = 0;` |
| // `let end = len;` |
| // `goto #1;` |
| let inits = vec![ |
| self.make_statement( |
| StatementKind::Assign( |
| box( |
| Place::from(beg), |
| Rvalue::Use(Operand::Constant(self.make_usize(0))) |
| ) |
| ) |
| ), |
| self.make_statement( |
| StatementKind::Assign( |
| box( |
| end.clone(), |
| Rvalue::Use(Operand::Constant(self.make_usize(len))) |
| ) |
| ) |
| ) |
| ]; |
| self.block(inits, TerminatorKind::Goto { target: BasicBlock::new(1) }, false); |
| |
| // BB #1: loop { |
| // BB #2; |
| // BB #3; |
| // } |
| // BB #4; |
| self.loop_header(Place::from(beg), |
| end, |
| BasicBlock::new(2), |
| BasicBlock::new(4), |
| false); |
| |
| // BB #2 |
| // `dest[i] = Clone::clone(src[beg])`; |
| // Goto #3 if ok, #5 if unwinding happens. |
| let dest_field = self.tcx.mk_place_index(dest.clone(), beg); |
| let src_field = self.tcx.mk_place_index(src, beg); |
| self.make_clone_call(dest_field, src_field, ty, BasicBlock::new(3), |
| BasicBlock::new(5)); |
| |
| // BB #3 |
| // `beg = beg + 1;` |
| // `goto #1`; |
| let statements = vec![ |
| self.make_statement( |
| StatementKind::Assign( |
| box( |
| Place::from(beg), |
| Rvalue::BinaryOp( |
| BinOp::Add, |
| Operand::Copy(Place::from(beg)), |
| Operand::Constant(self.make_usize(1)) |
| ) |
| ) |
| ) |
| ) |
| ]; |
| self.block(statements, TerminatorKind::Goto { target: BasicBlock::new(1) }, false); |
| |
| // BB #4 |
| // `return dest;` |
| self.block(vec![], TerminatorKind::Return, false); |
| |
| // BB #5 (cleanup) |
| // `let end = beg;` |
| // `let mut beg = 0;` |
| // goto #6; |
| let end = beg; |
| let beg = self.local_decls.push(temp_decl(Mutability::Mut, tcx.types.usize, span)); |
| let init = self.make_statement( |
| StatementKind::Assign( |
| box( |
| Place::from(beg), |
| Rvalue::Use(Operand::Constant(self.make_usize(0))) |
| ) |
| ) |
| ); |
| self.block(vec![init], TerminatorKind::Goto { target: BasicBlock::new(6) }, true); |
| |
| // BB #6 (cleanup): loop { |
| // BB #7; |
| // BB #8; |
| // } |
| // BB #9; |
| self.loop_header(Place::from(beg), Place::from(end), |
| BasicBlock::new(7), BasicBlock::new(9), true); |
| |
| // BB #7 (cleanup) |
| // `drop(dest[beg])`; |
| self.block(vec![], TerminatorKind::Drop { |
| location: self.tcx.mk_place_index(dest, beg), |
| target: BasicBlock::new(8), |
| unwind: None, |
| }, true); |
| |
| // BB #8 (cleanup) |
| // `beg = beg + 1;` |
| // `goto #6;` |
| let statement = self.make_statement( |
| StatementKind::Assign( |
| box( |
| Place::from(beg), |
| Rvalue::BinaryOp( |
| BinOp::Add, |
| Operand::Copy(Place::from(beg)), |
| Operand::Constant(self.make_usize(1)) |
| ) |
| ) |
| ) |
| ); |
| self.block(vec![statement], TerminatorKind::Goto { target: BasicBlock::new(6) }, true); |
| |
| // BB #9 (resume) |
| self.block(vec![], TerminatorKind::Resume, true); |
| } |
| |
| fn tuple_like_shim<I>(&mut self, dest: Place<'tcx>, |
| src: Place<'tcx>, tys: I) |
| where I: Iterator<Item = Ty<'tcx>> { |
| let mut previous_field = None; |
| for (i, ity) in tys.enumerate() { |
| let field = Field::new(i); |
| let src_field = self.tcx.mk_place_field(src.clone(), field, ity); |
| |
| let dest_field = self.tcx.mk_place_field(dest.clone(), 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.clone(), |
| 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 { |
| location: 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`. |
| /// |
| /// If `untuple_args` is a vec of types, the second argument of the |
| /// function will be untupled as these types. |
| fn build_call_shim<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| instance: ty::InstanceDef<'tcx>, |
| rcvr_adjustment: Adjustment, |
| call_kind: CallKind, |
| untuple_args: Option<&[Ty<'tcx>]>, |
| ) -> BodyCache<'tcx> { |
| debug!("build_call_shim(instance={:?}, rcvr_adjustment={:?}, \ |
| call_kind={:?}, untuple_args={:?})", |
| instance, rcvr_adjustment, call_kind, untuple_args); |
| |
| let def_id = instance.def_id(); |
| let sig = tcx.fn_sig(def_id); |
| let mut sig = tcx.erase_late_bound_regions(&sig); |
| |
| // 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 { span, scope: OUTERMOST_SOURCE_SCOPE }; |
| |
| let rcvr_arg = Local::new(1+0); |
| let rcvr_l = Place::from(rcvr_arg); |
| let mut statements = vec![]; |
| |
| let rcvr = match rcvr_adjustment { |
| Adjustment::Identity => Operand::Move(rcvr_l), |
| Adjustment::Deref => Operand::Copy(tcx.mk_place_deref(rcvr_l)), |
| Adjustment::DerefMove => Operand::Move(tcx.mk_place_deref(rcvr_l)), |
| Adjustment::RefMut => { |
| // let rcvr = &mut rcvr; |
| let ref_rcvr = local_decls.push(temp_decl( |
| Mutability::Not, |
| tcx.mk_ref(tcx.lifetimes.re_erased, ty::TypeAndMut { |
| ty: sig.inputs()[0], |
| mutbl: hir::Mutability::Mutable |
| }), |
| span |
| )); |
| let borrow_kind = BorrowKind::Mut { |
| allow_two_phase_borrow: false, |
| }; |
| statements.push(Statement { |
| source_info, |
| kind: StatementKind::Assign( |
| box( |
| Place::from(ref_rcvr), |
| Rvalue::Ref(tcx.lifetimes.re_erased, borrow_kind, rcvr_l) |
| ) |
| ) |
| }); |
| Operand::Move(Place::from(ref_rcvr)) |
| } |
| }; |
| |
| let (callee, mut args) = match call_kind { |
| CallKind::Indirect => (rcvr, vec![]), |
| CallKind::Direct(def_id) => { |
| let ty = tcx.type_of(def_id); |
| (Operand::Constant(box Constant { |
| span, |
| user_ty: None, |
| literal: ty::Const::zero_sized(tcx, ty), |
| }), |
| vec![rcvr]) |
| } |
| }; |
| |
| if let Some(untuple_args) = untuple_args { |
| args.extend(untuple_args.iter().enumerate().map(|(i, ity)| { |
| let arg_place = Place::from(Local::new(1+1)); |
| Operand::Move(tcx.mk_place_field(arg_place, Field::new(i), *ity)) |
| })); |
| } else { |
| args.extend((1..sig.inputs().len()).map(|i| { |
| Operand::Move(Place::from(Local::new(1+i))) |
| })); |
| } |
| |
| let n_blocks = if let 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: Some((Place::return_place(), |
| BasicBlock::new(1))), |
| cleanup: if let Adjustment::RefMut = rcvr_adjustment { |
| Some(BasicBlock::new(3)) |
| } else { |
| None |
| }, |
| from_hir_call: true, |
| }, false); |
| |
| if let Adjustment::RefMut = rcvr_adjustment { |
| // BB #1 - drop for Self |
| block(&mut blocks, vec![], TerminatorKind::Drop { |
| location: Place::from(rcvr_arg), |
| target: BasicBlock::new(2), |
| unwind: None |
| }, false); |
| } |
| // BB #1/#2 - return |
| block(&mut blocks, vec![], TerminatorKind::Return, false); |
| if let Adjustment::RefMut = rcvr_adjustment { |
| // BB #3 - drop if closure panics |
| block(&mut blocks, vec![], TerminatorKind::Drop { |
| location: Place::from(rcvr_arg), |
| target: BasicBlock::new(4), |
| unwind: None |
| }, true); |
| |
| // BB #4 - resume |
| block(&mut blocks, vec![], TerminatorKind::Resume, true); |
| } |
| |
| let mut body = new_body( |
| blocks, |
| local_decls, |
| sig.inputs().len(), |
| span, |
| ); |
| |
| if let Abi::RustCall = sig.abi { |
| body.spread_arg = Some(Local::new(sig.inputs().len())); |
| } |
| BodyCache::new(body) |
| } |
| |
| pub fn build_adt_ctor(tcx: TyCtxt<'_>, ctor_id: DefId) -> &BodyCache<'_> { |
| debug_assert!(tcx.is_constructor(ctor_id)); |
| |
| let span = tcx.hir().span_if_local(ctor_id) |
| .unwrap_or_else(|| bug!("no span for ctor {:?}", 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 (adt_def, substs) = match sig.output().kind { |
| ty::Adt(adt_def, substs) => (adt_def, substs), |
| _ => bug!("unexpected type for ADT ctor {:?}", sig.output()) |
| }; |
| |
| debug!("build_ctor: ctor_id={:?} sig={:?}", ctor_id, sig); |
| |
| let local_decls = local_decls_for_sig(&sig, span); |
| |
| let source_info = SourceInfo { |
| span, |
| scope: OUTERMOST_SOURCE_SCOPE |
| }; |
| |
| 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 |
| .variants[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, 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 body = new_body( |
| IndexVec::from_elem_n(start_block, 1), |
| local_decls, |
| sig.inputs().len(), |
| span, |
| ); |
| |
| crate::util::dump_mir( |
| tcx, |
| None, |
| "mir_map", |
| &0, |
| crate::transform::MirSource::item(ctor_id), |
| &body, |
| |_, _| Ok(()), |
| ); |
| |
| let mut body = BodyCache::new(body); |
| body.ensure_predecessors(); |
| tcx.arena.alloc(body) |
| } |
