diff options
Diffstat (limited to 'compiler/rustc_middle/src/ty/util.rs')
| -rw-r--r-- | compiler/rustc_middle/src/ty/util.rs | 151 |
1 files changed, 49 insertions, 102 deletions
diff --git a/compiler/rustc_middle/src/ty/util.rs b/compiler/rustc_middle/src/ty/util.rs index 08cee1101d0..f5158edffcf 100644 --- a/compiler/rustc_middle/src/ty/util.rs +++ b/compiler/rustc_middle/src/ty/util.rs @@ -468,25 +468,6 @@ impl<'tcx> TyCtxt<'tcx> { Some(ty::AsyncDestructor { impl_did: dtor_candidate? }) } - /// Returns async drop glue morphology for a definition. To get async drop - /// glue morphology for a type see [`Ty::async_drop_glue_morphology`]. - // - // FIXME: consider making this a query - pub fn async_drop_glue_morphology(self, did: DefId) -> AsyncDropGlueMorphology { - let ty: Ty<'tcx> = self.type_of(did).instantiate_identity(); - - // Async drop glue morphology is an internal detail, so - // using `TypingMode::PostAnalysis` probably should be fine. - let typing_env = ty::TypingEnv::fully_monomorphized(); - if ty.needs_async_drop(self, typing_env) { - AsyncDropGlueMorphology::Custom - } else if ty.needs_drop(self, typing_env) { - AsyncDropGlueMorphology::DeferredDropInPlace - } else { - AsyncDropGlueMorphology::Noop - } - } - /// Returns the set of types that are required to be alive in /// order to run the destructor of `def` (see RFCs 769 and /// 1238). @@ -911,7 +892,7 @@ impl<'tcx> TyCtxt<'tcx> { || self.extern_crate(key).is_some_and(|e| e.is_direct()) } - /// Expand any [weak alias types][weak] contained within the given `value`. + /// Expand any [free alias types][free] contained within the given `value`. /// /// This should be used over other normalization routines in situations where /// it's important not to normalize other alias types and where the predicates @@ -926,19 +907,19 @@ impl<'tcx> TyCtxt<'tcx> { /// <div class="warning"> /// This delays a bug on overflow! Therefore you need to be certain that the /// contained types get fully normalized at a later stage. Note that even on - /// overflow all well-behaved weak alias types get expanded correctly, so the + /// overflow all well-behaved free alias types get expanded correctly, so the /// result is still useful. /// </div> /// - /// [weak]: ty::Weak - pub fn expand_weak_alias_tys<T: TypeFoldable<TyCtxt<'tcx>>>(self, value: T) -> T { - value.fold_with(&mut WeakAliasTypeExpander { tcx: self, depth: 0 }) + /// [free]: ty::Free + pub fn expand_free_alias_tys<T: TypeFoldable<TyCtxt<'tcx>>>(self, value: T) -> T { + value.fold_with(&mut FreeAliasTypeExpander { tcx: self, depth: 0 }) } - /// Peel off all [weak alias types] in this type until there are none left. + /// Peel off all [free alias types] in this type until there are none left. /// - /// This only expands weak alias types in “head” / outermost positions. It can - /// be used over [expand_weak_alias_tys] as an optimization in situations where + /// This only expands free alias types in “head” / outermost positions. It can + /// be used over [expand_free_alias_tys] as an optimization in situations where /// one only really cares about the *kind* of the final aliased type but not /// the types the other constituent types alias. /// @@ -947,17 +928,17 @@ impl<'tcx> TyCtxt<'tcx> { /// type gets fully normalized at a later stage. /// </div> /// - /// [weak]: ty::Weak - /// [expand_weak_alias_tys]: Self::expand_weak_alias_tys - pub fn peel_off_weak_alias_tys(self, mut ty: Ty<'tcx>) -> Ty<'tcx> { - let ty::Alias(ty::Weak, _) = ty.kind() else { return ty }; + /// [free]: ty::Free + /// [expand_free_alias_tys]: Self::expand_free_alias_tys + pub fn peel_off_free_alias_tys(self, mut ty: Ty<'tcx>) -> Ty<'tcx> { + let ty::Alias(ty::Free, _) = ty.kind() else { return ty }; let limit = self.recursion_limit(); let mut depth = 0; - while let ty::Alias(ty::Weak, alias) = ty.kind() { + while let ty::Alias(ty::Free, alias) = ty.kind() { if !limit.value_within_limit(depth) { - let guar = self.dcx().delayed_bug("overflow expanding weak alias type"); + let guar = self.dcx().delayed_bug("overflow expanding free alias type"); return Ty::new_error(self, guar); } @@ -985,7 +966,7 @@ impl<'tcx> TyCtxt<'tcx> { } ty::AliasTermKind::OpaqueTy => Some(self.variances_of(def_id)), ty::AliasTermKind::InherentTy - | ty::AliasTermKind::WeakTy + | ty::AliasTermKind::FreeTy | ty::AliasTermKind::UnevaluatedConst | ty::AliasTermKind::ProjectionConst => None, } @@ -1078,25 +1059,25 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for OpaqueTypeExpander<'tcx> { } } -struct WeakAliasTypeExpander<'tcx> { +struct FreeAliasTypeExpander<'tcx> { tcx: TyCtxt<'tcx>, depth: usize, } -impl<'tcx> TypeFolder<TyCtxt<'tcx>> for WeakAliasTypeExpander<'tcx> { +impl<'tcx> TypeFolder<TyCtxt<'tcx>> for FreeAliasTypeExpander<'tcx> { fn cx(&self) -> TyCtxt<'tcx> { self.tcx } fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> { - if !ty.has_type_flags(ty::TypeFlags::HAS_TY_WEAK) { + if !ty.has_type_flags(ty::TypeFlags::HAS_TY_FREE_ALIAS) { return ty; } - let ty::Alias(ty::Weak, alias) = ty.kind() else { + let ty::Alias(ty::Free, alias) = ty.kind() else { return ty.super_fold_with(self); }; if !self.tcx.recursion_limit().value_within_limit(self.depth) { - let guar = self.tcx.dcx().delayed_bug("overflow expanding weak alias type"); + let guar = self.tcx.dcx().delayed_bug("overflow expanding free alias type"); return Ty::new_error(self.tcx, guar); } @@ -1107,25 +1088,13 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for WeakAliasTypeExpander<'tcx> { } fn fold_const(&mut self, ct: ty::Const<'tcx>) -> ty::Const<'tcx> { - if !ct.has_type_flags(ty::TypeFlags::HAS_TY_WEAK) { + if !ct.has_type_flags(ty::TypeFlags::HAS_TY_FREE_ALIAS) { return ct; } ct.super_fold_with(self) } } -/// Indicates the form of `AsyncDestruct::Destructor`. Used to simplify async -/// drop glue for types not using async drop. -#[derive(Clone, Copy, PartialEq, Eq, Debug)] -pub enum AsyncDropGlueMorphology { - /// Async destructor simply does nothing - Noop, - /// Async destructor simply runs `drop_in_place` - DeferredDropInPlace, - /// Async destructor has custom logic - Custom, -} - impl<'tcx> Ty<'tcx> { /// Returns the `Size` for primitive types (bool, uint, int, char, float). pub fn primitive_size(self, tcx: TyCtxt<'tcx>) -> Size { @@ -1295,16 +1264,17 @@ impl<'tcx> Ty<'tcx> { } } - /// Get morphology of the async drop glue, needed for types which do not - /// use async drop. To get async drop glue morphology for a definition see - /// [`TyCtxt::async_drop_glue_morphology`]. Used for `AsyncDestruct::Destructor` - /// type construction. - // - // FIXME: implement optimization to not instantiate a certain morphology of - // async drop glue too soon to allow per type optimizations, see array case - // for more info. Perhaps then remove this method and use `needs_(async_)drop` - // instead. - pub fn async_drop_glue_morphology(self, tcx: TyCtxt<'tcx>) -> AsyncDropGlueMorphology { + /// Checks whether values of this type `T` implement the `AsyncDrop` trait. + pub fn is_async_drop(self, tcx: TyCtxt<'tcx>, typing_env: ty::TypingEnv<'tcx>) -> bool { + !self.is_trivially_not_async_drop() + && tcx.is_async_drop_raw(typing_env.as_query_input(self)) + } + + /// Fast path helper for testing if a type is `AsyncDrop`. + /// + /// Returning true means the type is known to be `!AsyncDrop`. Returning + /// `false` means nothing -- could be `AsyncDrop`, might not be. + fn is_trivially_not_async_drop(self) -> bool { match self.kind() { ty::Int(_) | ty::Uint(_) @@ -1316,46 +1286,26 @@ impl<'tcx> Ty<'tcx> { | ty::Ref(..) | ty::RawPtr(..) | ty::FnDef(..) - | ty::FnPtr(..) - | ty::Infer(ty::FreshIntTy(_)) - | ty::Infer(ty::FreshFloatTy(_)) => AsyncDropGlueMorphology::Noop, - + | ty::Error(_) + | ty::FnPtr(..) => true, // FIXME(unsafe_binders): ty::UnsafeBinder(_) => todo!(), - - ty::Tuple(tys) if tys.is_empty() => AsyncDropGlueMorphology::Noop, - ty::Adt(adt_def, _) if adt_def.is_manually_drop() => AsyncDropGlueMorphology::Noop, - - // Foreign types can never have destructors. - ty::Foreign(_) => AsyncDropGlueMorphology::Noop, - - // FIXME: implement dynamic types async drops - ty::Error(_) | ty::Dynamic(..) => AsyncDropGlueMorphology::DeferredDropInPlace, - - ty::Tuple(_) | ty::Array(_, _) | ty::Slice(_) => { - // Assume worst-case scenario, because we can instantiate async - // destructors in different orders: - // - // 1. Instantiate [T; N] with T = String and N = 0 - // 2. Instantiate <[String; 0] as AsyncDestruct>::Destructor - // - // And viceversa, thus we cannot rely on String not using async - // drop or array having zero (0) elements - AsyncDropGlueMorphology::Custom - } - ty::Pat(ty, _) => ty.async_drop_glue_morphology(tcx), - - ty::Adt(adt_def, _) => tcx.async_drop_glue_morphology(adt_def.did()), - - ty::Closure(did, _) - | ty::CoroutineClosure(did, _) - | ty::Coroutine(did, _) - | ty::CoroutineWitness(did, _) => tcx.async_drop_glue_morphology(*did), - - ty::Alias(..) | ty::Param(_) | ty::Bound(..) | ty::Placeholder(..) | ty::Infer(_) => { - // No specifics, but would usually mean forwarding async drop glue - AsyncDropGlueMorphology::Custom + ty::Tuple(fields) => fields.iter().all(Self::is_trivially_not_async_drop), + ty::Pat(elem_ty, _) | ty::Slice(elem_ty) | ty::Array(elem_ty, _) => { + elem_ty.is_trivially_not_async_drop() } + ty::Adt(..) + | ty::Bound(..) + | ty::Closure(..) + | ty::CoroutineClosure(..) + | ty::Dynamic(..) + | ty::Foreign(_) + | ty::Coroutine(..) + | ty::CoroutineWitness(..) + | ty::Infer(_) + | ty::Alias(..) + | ty::Param(_) + | ty::Placeholder(_) => false, } } @@ -1401,9 +1351,6 @@ impl<'tcx> Ty<'tcx> { /// (Note that this implies that if `ty` has an async destructor attached, /// then `needs_async_drop` will definitely return `true` for `ty`.) /// - /// When constructing `AsyncDestruct::Destructor` type, use - /// [`Ty::async_drop_glue_morphology`] instead. - // // FIXME(zetanumbers): Note that this method is used to check eligible types // in unions. #[inline] |