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Auto merge of #15135 - HKalbasi:mir, r=HKalbasi
Fix some unsizing problems in mir
| -rw-r--r-- | crates/hir-ty/src/consteval/tests.rs | 49 | ||||
| -rw-r--r-- | crates/hir-ty/src/layout/tests.rs | 8 | ||||
| -rw-r--r-- | crates/hir-ty/src/mir/eval.rs | 101 | ||||
| -rw-r--r-- | crates/hir-ty/src/mir/lower.rs | 12 | ||||
| -rw-r--r-- | crates/test-utils/src/minicore.rs | 14 |
5 files changed, 134 insertions, 50 deletions
diff --git a/crates/hir-ty/src/consteval/tests.rs b/crates/hir-ty/src/consteval/tests.rs index b487d7d049..de3a947f35 100644 --- a/crates/hir-ty/src/consteval/tests.rs +++ b/crates/hir-ty/src/consteval/tests.rs @@ -166,14 +166,21 @@ fn casts() { check_number( r#" //- minicore: coerce_unsized, index, slice + struct X { + unsize_field: [u8], + } + const GOAL: usize = { let a = [10, 20, 3, 15]; let x: &[i32] = &a; - let y: *const [i32] = x; - let z = y as *const [u8]; // slice fat pointer cast don't touch metadata - let q = z as *const str; - let p = q as *const [u8]; - let w = unsafe { &*z }; + let x: *const [i32] = x; + let x = x as *const [u8]; // slice fat pointer cast don't touch metadata + let x = x as *const str; + let x = x as *const X; + let x = x as *const [i16]; + let x = x as *const X; + let x = x as *const [u8]; + let w = unsafe { &*x }; w.len() }; "#, @@ -1874,6 +1881,38 @@ fn dyn_trait() { } #[test] +fn coerce_unsized() { + check_number( + r#" +//- minicore: coerce_unsized, deref_mut, slice, index, transmute, non_null +use core::ops::{Deref, DerefMut, CoerceUnsized}; +use core::{marker::Unsize, mem::transmute, ptr::NonNull}; + +struct ArcInner<T: ?Sized> { + strong: usize, + weak: usize, + data: T, +} + +pub struct Arc<T: ?Sized> { + inner: NonNull<ArcInner<T>>, +} + +impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<Arc<U>> for Arc<T> {} + +const GOAL: usize = { + let x = transmute::<usize, Arc<[i32; 3]>>(12); + let y: Arc<[i32]> = x; + let z = transmute::<Arc<[i32]>, (usize, usize)>(y); + z.1 +}; + + "#, + 3, + ); +} + +#[test] fn boxes() { check_number( r#" diff --git a/crates/hir-ty/src/layout/tests.rs b/crates/hir-ty/src/layout/tests.rs index 0ff8c532d4..b75f213df2 100644 --- a/crates/hir-ty/src/layout/tests.rs +++ b/crates/hir-ty/src/layout/tests.rs @@ -369,11 +369,11 @@ fn tuple() { } #[test] -fn non_zero() { +fn non_zero_and_non_null() { size_and_align! { - minicore: non_zero, option; - use core::num::NonZeroU8; - struct Goal(Option<NonZeroU8>); + minicore: non_zero, non_null, option; + use core::{num::NonZeroU8, ptr::NonNull}; + struct Goal(Option<NonZeroU8>, Option<NonNull<i32>>); } } diff --git a/crates/hir-ty/src/mir/eval.rs b/crates/hir-ty/src/mir/eval.rs index 78961e1982..01295a9fc3 100644 --- a/crates/hir-ty/src/mir/eval.rs +++ b/crates/hir-ty/src/mir/eval.rs @@ -1263,50 +1263,81 @@ impl Evaluator<'_> { current_ty: &Ty, target_ty: &Ty, ) -> Result<IntervalOrOwned> { - use IntervalOrOwned::*; fn for_ptr(x: &TyKind) -> Option<Ty> { match x { TyKind::Raw(_, ty) | TyKind::Ref(_, _, ty) => Some(ty.clone()), _ => None, } } - Ok(match self.coerce_unsized_look_through_fields(target_ty, for_ptr)? { - ty => match &ty.data(Interner).kind { - TyKind::Slice(_) => { - match self.coerce_unsized_look_through_fields(current_ty, for_ptr)? { - ty => match &ty.data(Interner).kind { - TyKind::Array(_, size) => { - let len = match try_const_usize(self.db, size) { - None => not_supported!( - "unevaluatble len of array in coerce unsized" - ), - Some(x) => x as usize, - }; - let mut r = Vec::with_capacity(16); - let addr = addr.get(self)?; - r.extend(addr.iter().copied()); - r.extend(len.to_le_bytes().into_iter()); - Owned(r) - } - t => { - not_supported!("slice unsizing from non array type {t:?}") - } - }, - } + let target_ty = self.coerce_unsized_look_through_fields(target_ty, for_ptr)?; + let current_ty = self.coerce_unsized_look_through_fields(current_ty, for_ptr)?; + + self.unsizing_ptr_from_addr(target_ty, current_ty, addr) + } + + /// Adds metadata to the address and create the fat pointer result of the unsizing operation. + fn unsizing_ptr_from_addr( + &mut self, + target_ty: Ty, + current_ty: Ty, + addr: Interval, + ) -> Result<IntervalOrOwned> { + use IntervalOrOwned::*; + Ok(match &target_ty.data(Interner).kind { + TyKind::Slice(_) => match ¤t_ty.data(Interner).kind { + TyKind::Array(_, size) => { + let len = match try_const_usize(self.db, size) { + None => { + not_supported!("unevaluatble len of array in coerce unsized") + } + Some(x) => x as usize, + }; + let mut r = Vec::with_capacity(16); + let addr = addr.get(self)?; + r.extend(addr.iter().copied()); + r.extend(len.to_le_bytes().into_iter()); + Owned(r) } - TyKind::Dyn(_) => match ¤t_ty.data(Interner).kind { - TyKind::Raw(_, ty) | TyKind::Ref(_, _, ty) => { - let vtable = self.vtable_map.id(ty.clone()); - let mut r = Vec::with_capacity(16); - let addr = addr.get(self)?; - r.extend(addr.iter().copied()); - r.extend(vtable.to_le_bytes().into_iter()); - Owned(r) + t => { + not_supported!("slice unsizing from non array type {t:?}") + } + }, + TyKind::Dyn(_) => { + let vtable = self.vtable_map.id(current_ty.clone()); + let mut r = Vec::with_capacity(16); + let addr = addr.get(self)?; + r.extend(addr.iter().copied()); + r.extend(vtable.to_le_bytes().into_iter()); + Owned(r) + } + TyKind::Adt(id, target_subst) => match ¤t_ty.data(Interner).kind { + TyKind::Adt(current_id, current_subst) => { + if id != current_id { + not_supported!("unsizing struct with different type"); } - _ => not_supported!("dyn unsizing from non pointers"), - }, - _ => not_supported!("unknown unsized cast"), + let id = match id.0 { + AdtId::StructId(s) => s, + AdtId::UnionId(_) => not_supported!("unsizing unions"), + AdtId::EnumId(_) => not_supported!("unsizing enums"), + }; + let Some((last_field, _)) = self.db.struct_data(id).variant_data.fields().iter().rev().next() else { + not_supported!("unsizing struct without field"); + }; + let target_last_field = self.db.field_types(id.into())[last_field] + .clone() + .substitute(Interner, target_subst); + let current_last_field = self.db.field_types(id.into())[last_field] + .clone() + .substitute(Interner, current_subst); + return self.unsizing_ptr_from_addr( + target_last_field, + current_last_field, + addr, + ); + } + _ => not_supported!("unsizing struct with non adt type"), }, + _ => not_supported!("unknown unsized cast"), }) } diff --git a/crates/hir-ty/src/mir/lower.rs b/crates/hir-ty/src/mir/lower.rs index 2cb29b4ab9..800e490e9a 100644 --- a/crates/hir-ty/src/mir/lower.rs +++ b/crates/hir-ty/src/mir/lower.rs @@ -1742,17 +1742,17 @@ fn cast_kind(source_ty: &Ty, target_ty: &Ty) -> Result<CastKind> { (TyKind::Raw(_, a) | TyKind::Ref(_, _, a), TyKind::Raw(_, b) | TyKind::Ref(_, _, b)) => { CastKind::Pointer(if a == b { PointerCast::MutToConstPointer - } else if matches!(a.kind(Interner), TyKind::Slice(_) | TyKind::Str) - && matches!(b.kind(Interner), TyKind::Slice(_) | TyKind::Str) + } else if matches!(b.kind(Interner), TyKind::Slice(_)) + && matches!(a.kind(Interner), TyKind::Array(_, _)) + || matches!(b.kind(Interner), TyKind::Dyn(_)) { - // slice to slice cast is no-op (metadata is not touched), so we use this - PointerCast::MutToConstPointer - } else if matches!(b.kind(Interner), TyKind::Slice(_) | TyKind::Dyn(_)) { PointerCast::Unsize } else if matches!(a.kind(Interner), TyKind::Slice(s) if s == b) { PointerCast::ArrayToPointer } else { - // cast between two sized pointer, like *const i32 to *const i8. There is no specific variant + // cast between two sized pointer, like *const i32 to *const i8, or two unsized pointer, like + // slice to slice, slice to str, ... . These are no-ops (even in the unsized case, no metadata + // will be touched) but there is no specific variant // for it in `PointerCast` so we use `MutToConstPointer` PointerCast::MutToConstPointer }) diff --git a/crates/test-utils/src/minicore.rs b/crates/test-utils/src/minicore.rs index 0d6e4b98d8..d7201f996d 100644 --- a/crates/test-utils/src/minicore.rs +++ b/crates/test-utils/src/minicore.rs @@ -37,6 +37,7 @@ //! iterator: option //! iterators: iterator, fn //! manually_drop: drop +//! non_null: //! non_zero: //! option: panic //! ord: eq, option @@ -386,6 +387,19 @@ pub mod ptr { type Metadata; } // endregion:pointee + // region:non_null + #[rustc_layout_scalar_valid_range_start(1)] + #[rustc_nonnull_optimization_guaranteed] + pub struct NonNull<T: ?Sized> { + pointer: *const T, + } + // region:coerce_unsized + impl<T: ?Sized, U: ?Sized> crate::ops::CoerceUnsized<NonNull<U>> for NonNull<T> where + T: crate::marker::Unsize<U> + { + } + // endregion:coerce_unsized + // endregion:non_null } pub mod ops { |