| use crate::ty::{self, InferConst, Ty, TypeFlags}; |
| use crate::ty::{GenericArg, GenericArgKind}; |
| use std::slice; |
| |
| #[derive(Debug)] |
| pub struct FlagComputation { |
| pub flags: TypeFlags, |
| |
| /// see `Ty::outer_exclusive_binder` for details |
| pub outer_exclusive_binder: ty::DebruijnIndex, |
| } |
| |
| impl FlagComputation { |
| fn new() -> FlagComputation { |
| FlagComputation { flags: TypeFlags::empty(), outer_exclusive_binder: ty::INNERMOST } |
| } |
| |
| #[allow(rustc::usage_of_ty_tykind)] |
| pub fn for_kind(kind: &ty::TyKind<'_>) -> FlagComputation { |
| let mut result = FlagComputation::new(); |
| result.add_kind(kind); |
| result |
| } |
| |
| pub fn for_predicate(binder: ty::Binder<'_, ty::PredicateKind<'_>>) -> FlagComputation { |
| let mut result = FlagComputation::new(); |
| result.add_predicate(binder); |
| result |
| } |
| |
| pub fn for_const(c: &ty::ConstKind<'_>, t: Ty<'_>) -> FlagComputation { |
| let mut result = FlagComputation::new(); |
| result.add_const_kind(c); |
| result.add_ty(t); |
| result |
| } |
| |
| fn add_flags(&mut self, flags: TypeFlags) { |
| self.flags = self.flags | flags; |
| } |
| |
| /// indicates that `self` refers to something at binding level `binder` |
| fn add_bound_var(&mut self, binder: ty::DebruijnIndex) { |
| let exclusive_binder = binder.shifted_in(1); |
| self.add_exclusive_binder(exclusive_binder); |
| } |
| |
| /// indicates that `self` refers to something *inside* binding |
| /// level `binder` -- not bound by `binder`, but bound by the next |
| /// binder internal to it |
| fn add_exclusive_binder(&mut self, exclusive_binder: ty::DebruijnIndex) { |
| self.outer_exclusive_binder = self.outer_exclusive_binder.max(exclusive_binder); |
| } |
| |
| /// Adds the flags/depth from a set of types that appear within the current type, but within a |
| /// region binder. |
| fn bound_computation<T, F>(&mut self, value: ty::Binder<'_, T>, f: F) |
| where |
| F: FnOnce(&mut Self, T), |
| { |
| let mut computation = FlagComputation::new(); |
| |
| if !value.bound_vars().is_empty() { |
| computation.add_flags(TypeFlags::HAS_BINDER_VARS); |
| } |
| |
| f(&mut computation, value.skip_binder()); |
| |
| self.add_flags(computation.flags); |
| |
| // The types that contributed to `computation` occurred within |
| // a region binder, so subtract one from the region depth |
| // within when adding the depth to `self`. |
| let outer_exclusive_binder = computation.outer_exclusive_binder; |
| if outer_exclusive_binder > ty::INNERMOST { |
| self.add_exclusive_binder(outer_exclusive_binder.shifted_out(1)); |
| } // otherwise, this binder captures nothing |
| } |
| |
| #[allow(rustc::usage_of_ty_tykind)] |
| fn add_kind(&mut self, kind: &ty::TyKind<'_>) { |
| match kind { |
| &ty::Bool |
| | &ty::Char |
| | &ty::Int(_) |
| | &ty::Float(_) |
| | &ty::Uint(_) |
| | &ty::Never |
| | &ty::Str |
| | &ty::Foreign(..) => {} |
| |
| &ty::Error(_) => self.add_flags(TypeFlags::HAS_ERROR), |
| |
| &ty::Param(_) => { |
| self.add_flags(TypeFlags::HAS_TY_PARAM); |
| self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE); |
| } |
| |
| ty::Coroutine(_, args) => { |
| let args = args.as_coroutine(); |
| let should_remove_further_specializable = |
| !self.flags.contains(TypeFlags::STILL_FURTHER_SPECIALIZABLE); |
| self.add_args(args.parent_args()); |
| if should_remove_further_specializable { |
| self.flags -= TypeFlags::STILL_FURTHER_SPECIALIZABLE; |
| } |
| |
| self.add_ty(args.resume_ty()); |
| self.add_ty(args.return_ty()); |
| self.add_ty(args.witness()); |
| self.add_ty(args.yield_ty()); |
| self.add_ty(args.tupled_upvars_ty()); |
| } |
| |
| ty::CoroutineWitness(_, args) => { |
| let should_remove_further_specializable = |
| !self.flags.contains(TypeFlags::STILL_FURTHER_SPECIALIZABLE); |
| self.add_args(args); |
| if should_remove_further_specializable { |
| self.flags -= TypeFlags::STILL_FURTHER_SPECIALIZABLE; |
| } |
| self.add_flags(TypeFlags::HAS_TY_COROUTINE); |
| } |
| |
| &ty::Closure(_, args) => { |
| let args = args.as_closure(); |
| let should_remove_further_specializable = |
| !self.flags.contains(TypeFlags::STILL_FURTHER_SPECIALIZABLE); |
| self.add_args(args.parent_args()); |
| if should_remove_further_specializable { |
| self.flags -= TypeFlags::STILL_FURTHER_SPECIALIZABLE; |
| } |
| |
| self.add_ty(args.sig_as_fn_ptr_ty()); |
| self.add_ty(args.kind_ty()); |
| self.add_ty(args.tupled_upvars_ty()); |
| } |
| |
| &ty::Bound(debruijn, _) => { |
| self.add_bound_var(debruijn); |
| self.add_flags(TypeFlags::HAS_TY_BOUND); |
| } |
| |
| &ty::Placeholder(..) => { |
| self.add_flags(TypeFlags::HAS_TY_PLACEHOLDER); |
| self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE); |
| } |
| |
| &ty::Infer(infer) => { |
| self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE); |
| match infer { |
| ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_) => { |
| self.add_flags(TypeFlags::HAS_TY_FRESH) |
| } |
| |
| ty::TyVar(_) | ty::IntVar(_) | ty::FloatVar(_) => { |
| self.add_flags(TypeFlags::HAS_TY_INFER) |
| } |
| } |
| } |
| |
| &ty::Adt(_, args) => { |
| self.add_args(args); |
| } |
| |
| &ty::Alias(kind, data) => { |
| self.add_flags(match kind { |
| ty::Weak | ty::Projection => TypeFlags::HAS_TY_PROJECTION, |
| ty::Inherent => TypeFlags::HAS_TY_INHERENT, |
| ty::Opaque => TypeFlags::HAS_TY_OPAQUE, |
| }); |
| |
| self.add_alias_ty(data); |
| } |
| |
| &ty::Dynamic(obj, r, _) => { |
| for predicate in obj.iter() { |
| self.bound_computation(predicate, |computation, predicate| match predicate { |
| ty::ExistentialPredicate::Trait(tr) => computation.add_args(tr.args), |
| ty::ExistentialPredicate::Projection(p) => { |
| computation.add_existential_projection(&p); |
| } |
| ty::ExistentialPredicate::AutoTrait(_) => {} |
| }); |
| } |
| |
| self.add_region(r); |
| } |
| |
| &ty::Array(tt, len) => { |
| self.add_ty(tt); |
| self.add_const(len); |
| } |
| |
| &ty::Slice(tt) => self.add_ty(tt), |
| |
| ty::RawPtr(m) => { |
| self.add_ty(m.ty); |
| } |
| |
| &ty::Ref(r, ty, _) => { |
| self.add_region(r); |
| self.add_ty(ty); |
| } |
| |
| &ty::Tuple(types) => { |
| self.add_tys(types); |
| } |
| |
| &ty::FnDef(_, args) => { |
| self.add_args(args); |
| } |
| |
| &ty::FnPtr(fn_sig) => self.bound_computation(fn_sig, |computation, fn_sig| { |
| computation.add_tys(fn_sig.inputs()); |
| computation.add_ty(fn_sig.output()); |
| }), |
| } |
| } |
| |
| fn add_predicate(&mut self, binder: ty::Binder<'_, ty::PredicateKind<'_>>) { |
| self.bound_computation(binder, |computation, atom| computation.add_predicate_atom(atom)); |
| } |
| |
| fn add_predicate_atom(&mut self, atom: ty::PredicateKind<'_>) { |
| match atom { |
| ty::PredicateKind::Clause(ty::ClauseKind::Trait(trait_pred)) => { |
| self.add_args(trait_pred.trait_ref.args); |
| } |
| ty::PredicateKind::Clause(ty::ClauseKind::RegionOutlives(ty::OutlivesPredicate( |
| a, |
| b, |
| ))) => { |
| self.add_region(a); |
| self.add_region(b); |
| } |
| ty::PredicateKind::Clause(ty::ClauseKind::TypeOutlives(ty::OutlivesPredicate( |
| ty, |
| region, |
| ))) => { |
| self.add_ty(ty); |
| self.add_region(region); |
| } |
| ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(ct, ty)) => { |
| self.add_const(ct); |
| self.add_ty(ty); |
| } |
| ty::PredicateKind::Subtype(ty::SubtypePredicate { a_is_expected: _, a, b }) => { |
| self.add_ty(a); |
| self.add_ty(b); |
| } |
| ty::PredicateKind::Coerce(ty::CoercePredicate { a, b }) => { |
| self.add_ty(a); |
| self.add_ty(b); |
| } |
| ty::PredicateKind::Clause(ty::ClauseKind::Projection(ty::ProjectionPredicate { |
| projection_ty, |
| term, |
| })) => { |
| self.add_alias_ty(projection_ty); |
| self.add_term(term); |
| } |
| ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(arg)) => { |
| self.add_args(slice::from_ref(&arg)); |
| } |
| ty::PredicateKind::ObjectSafe(_def_id) => {} |
| ty::PredicateKind::Clause(ty::ClauseKind::ConstEvaluatable(uv)) => { |
| self.add_const(uv); |
| } |
| ty::PredicateKind::ConstEquate(expected, found) => { |
| self.add_const(expected); |
| self.add_const(found); |
| } |
| ty::PredicateKind::Ambiguous => {} |
| ty::PredicateKind::NormalizesTo(ty::NormalizesTo { alias, term }) => { |
| self.add_alias_ty(alias); |
| self.add_term(term); |
| } |
| ty::PredicateKind::AliasRelate(t1, t2, _) => { |
| self.add_term(t1); |
| self.add_term(t2); |
| } |
| } |
| } |
| |
| fn add_ty(&mut self, ty: Ty<'_>) { |
| self.add_flags(ty.flags()); |
| self.add_exclusive_binder(ty.outer_exclusive_binder()); |
| } |
| |
| fn add_tys(&mut self, tys: &[Ty<'_>]) { |
| for &ty in tys { |
| self.add_ty(ty); |
| } |
| } |
| |
| fn add_region(&mut self, r: ty::Region<'_>) { |
| self.add_flags(r.type_flags()); |
| if let ty::ReBound(debruijn, _) = *r { |
| self.add_bound_var(debruijn); |
| } |
| } |
| |
| fn add_const(&mut self, c: ty::Const<'_>) { |
| self.add_flags(c.flags()); |
| self.add_exclusive_binder(c.outer_exclusive_binder()); |
| } |
| |
| fn add_const_kind(&mut self, c: &ty::ConstKind<'_>) { |
| match *c { |
| ty::ConstKind::Unevaluated(uv) => { |
| self.add_args(uv.args); |
| self.add_flags(TypeFlags::HAS_CT_PROJECTION); |
| } |
| ty::ConstKind::Infer(infer) => { |
| self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE); |
| match infer { |
| InferConst::Fresh(_) => self.add_flags(TypeFlags::HAS_CT_FRESH), |
| InferConst::Var(_) | InferConst::EffectVar(_) => { |
| self.add_flags(TypeFlags::HAS_CT_INFER) |
| } |
| } |
| } |
| ty::ConstKind::Bound(debruijn, _) => { |
| self.add_bound_var(debruijn); |
| self.add_flags(TypeFlags::HAS_CT_BOUND); |
| } |
| ty::ConstKind::Param(_) => { |
| self.add_flags(TypeFlags::HAS_CT_PARAM); |
| self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE); |
| } |
| ty::ConstKind::Placeholder(_) => { |
| self.add_flags(TypeFlags::HAS_CT_PLACEHOLDER); |
| self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE); |
| } |
| ty::ConstKind::Value(_) => {} |
| ty::ConstKind::Expr(e) => { |
| use ty::Expr; |
| match e { |
| Expr::Binop(_, l, r) => { |
| self.add_const(l); |
| self.add_const(r); |
| } |
| Expr::UnOp(_, v) => self.add_const(v), |
| Expr::FunctionCall(f, args) => { |
| self.add_const(f); |
| for arg in args { |
| self.add_const(arg); |
| } |
| } |
| Expr::Cast(_, c, t) => { |
| self.add_ty(t); |
| self.add_const(c); |
| } |
| } |
| } |
| ty::ConstKind::Error(_) => self.add_flags(TypeFlags::HAS_ERROR), |
| } |
| } |
| |
| fn add_existential_projection(&mut self, projection: &ty::ExistentialProjection<'_>) { |
| self.add_args(projection.args); |
| match projection.term.unpack() { |
| ty::TermKind::Ty(ty) => self.add_ty(ty), |
| ty::TermKind::Const(ct) => self.add_const(ct), |
| } |
| } |
| |
| fn add_alias_ty(&mut self, alias_ty: ty::AliasTy<'_>) { |
| self.add_args(alias_ty.args); |
| } |
| |
| fn add_args(&mut self, args: &[GenericArg<'_>]) { |
| for kind in args { |
| match kind.unpack() { |
| GenericArgKind::Type(ty) => self.add_ty(ty), |
| GenericArgKind::Lifetime(lt) => self.add_region(lt), |
| GenericArgKind::Const(ct) => self.add_const(ct), |
| } |
| } |
| } |
| |
| fn add_term(&mut self, term: ty::Term<'_>) { |
| match term.unpack() { |
| ty::TermKind::Ty(ty) => self.add_ty(ty), |
| ty::TermKind::Const(ct) => self.add_const(ct), |
| } |
| } |
| } |
