diff options
Diffstat (limited to 'compiler/rustc_const_eval/src')
9 files changed, 129 insertions, 116 deletions
diff --git a/compiler/rustc_const_eval/src/interpret/cast.rs b/compiler/rustc_const_eval/src/interpret/cast.rs index 0a45bbb3edb..6961e13c239 100644 --- a/compiler/rustc_const_eval/src/interpret/cast.rs +++ b/compiler/rustc_const_eval/src/interpret/cast.rs @@ -387,7 +387,6 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { match (&src_pointee_ty.kind(), &dest_pointee_ty.kind()) { (&ty::Array(_, length), &ty::Slice(_)) => { let ptr = self.read_pointer(src)?; - // u64 cast is from usize to u64, which is always good let val = Immediate::new_slice( ptr, length.eval_target_usize(*self.tcx, self.param_env), @@ -405,13 +404,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { let (old_data, old_vptr) = val.to_scalar_pair(); let old_data = old_data.to_pointer(self)?; let old_vptr = old_vptr.to_pointer(self)?; - let (ty, old_trait) = self.get_ptr_vtable(old_vptr)?; - if old_trait != data_a.principal() { - throw_ub!(InvalidVTableTrait { - expected_trait: data_a, - vtable_trait: old_trait, - }); - } + let ty = self.get_ptr_vtable_ty(old_vptr, Some(data_a))?; let new_vptr = self.get_vtable_ptr(ty, data_b.principal())?; self.write_immediate(Immediate::new_dyn_trait(old_data, new_vptr, self), dest) } diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs index 7c2100fcbe3..e28cc05cc2a 100644 --- a/compiler/rustc_const_eval/src/interpret/eval_context.rs +++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs @@ -765,10 +765,10 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { } Ok(Some((full_size, full_align))) } - ty::Dynamic(_, _, ty::Dyn) => { + ty::Dynamic(expected_trait, _, ty::Dyn) => { let vtable = metadata.unwrap_meta().to_pointer(self)?; // Read size and align from vtable (already checks size). - Ok(Some(self.get_vtable_size_and_align(vtable)?)) + Ok(Some(self.get_vtable_size_and_align(vtable, Some(expected_trait))?)) } ty::Slice(_) | ty::Str => { diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics.rs b/compiler/rustc_const_eval/src/interpret/intrinsics.rs index 7f16d441606..1d54da267ee 100644 --- a/compiler/rustc_const_eval/src/interpret/intrinsics.rs +++ b/compiler/rustc_const_eval/src/interpret/intrinsics.rs @@ -432,12 +432,14 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { sym::vtable_size => { let ptr = self.read_pointer(&args[0])?; - let (size, _align) = self.get_vtable_size_and_align(ptr)?; + // `None` because we don't know which trait to expect here; any vtable is okay. + let (size, _align) = self.get_vtable_size_and_align(ptr, None)?; self.write_scalar(Scalar::from_target_usize(size.bytes(), self), dest)?; } sym::vtable_align => { let ptr = self.read_pointer(&args[0])?; - let (_size, align) = self.get_vtable_size_and_align(ptr)?; + // `None` because we don't know which trait to expect here; any vtable is okay. + let (_size, align) = self.get_vtable_size_and_align(ptr, None)?; self.write_scalar(Scalar::from_target_usize(align.bytes(), self), dest)?; } diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs index 7eb73e9b52f..5461e9c6ad3 100644 --- a/compiler/rustc_const_eval/src/interpret/memory.rs +++ b/compiler/rustc_const_eval/src/interpret/memory.rs @@ -867,19 +867,26 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { .ok_or_else(|| err_ub!(InvalidFunctionPointer(Pointer::new(alloc_id, offset))).into()) } - pub fn get_ptr_vtable( + /// Get the dynamic type of the given vtable pointer. + /// If `expected_trait` is `Some`, it must be a vtable for the given trait. + pub fn get_ptr_vtable_ty( &self, ptr: Pointer<Option<M::Provenance>>, - ) -> InterpResult<'tcx, (Ty<'tcx>, Option<ty::PolyExistentialTraitRef<'tcx>>)> { + expected_trait: Option<&'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>>, + ) -> InterpResult<'tcx, Ty<'tcx>> { trace!("get_ptr_vtable({:?})", ptr); let (alloc_id, offset, _tag) = self.ptr_get_alloc_id(ptr)?; if offset.bytes() != 0 { throw_ub!(InvalidVTablePointer(Pointer::new(alloc_id, offset))) } - match self.tcx.try_get_global_alloc(alloc_id) { - Some(GlobalAlloc::VTable(ty, trait_ref)) => Ok((ty, trait_ref)), - _ => throw_ub!(InvalidVTablePointer(Pointer::new(alloc_id, offset))), + let Some(GlobalAlloc::VTable(ty, vtable_trait)) = self.tcx.try_get_global_alloc(alloc_id) + else { + throw_ub!(InvalidVTablePointer(Pointer::new(alloc_id, offset))) + }; + if let Some(expected_trait) = expected_trait { + self.check_vtable_for_type(vtable_trait, expected_trait)?; } + Ok(ty) } pub fn alloc_mark_immutable(&mut self, id: AllocId) -> InterpResult<'tcx> { diff --git a/compiler/rustc_const_eval/src/interpret/place.rs b/compiler/rustc_const_eval/src/interpret/place.rs index 046ff34e3d0..08d3165867c 100644 --- a/compiler/rustc_const_eval/src/interpret/place.rs +++ b/compiler/rustc_const_eval/src/interpret/place.rs @@ -9,7 +9,6 @@ use tracing::{instrument, trace}; use rustc_ast::Mutability; use rustc_middle::mir; -use rustc_middle::ty; use rustc_middle::ty::layout::{LayoutOf, TyAndLayout}; use rustc_middle::ty::Ty; use rustc_middle::{bug, span_bug}; @@ -1018,54 +1017,6 @@ where let layout = self.layout_of(raw.ty)?; Ok(self.ptr_to_mplace(ptr.into(), layout)) } - - /// Turn a place with a `dyn Trait` type into a place with the actual dynamic type. - /// Aso returns the vtable. - pub(super) fn unpack_dyn_trait( - &self, - mplace: &MPlaceTy<'tcx, M::Provenance>, - expected_trait: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>, - ) -> InterpResult<'tcx, (MPlaceTy<'tcx, M::Provenance>, Pointer<Option<M::Provenance>>)> { - assert!( - matches!(mplace.layout.ty.kind(), ty::Dynamic(_, _, ty::Dyn)), - "`unpack_dyn_trait` only makes sense on `dyn*` types" - ); - let vtable = mplace.meta().unwrap_meta().to_pointer(self)?; - let (ty, vtable_trait) = self.get_ptr_vtable(vtable)?; - if expected_trait.principal() != vtable_trait { - throw_ub!(InvalidVTableTrait { expected_trait, vtable_trait }); - } - // This is a kind of transmute, from a place with unsized type and metadata to - // a place with sized type and no metadata. - let layout = self.layout_of(ty)?; - let mplace = - MPlaceTy { mplace: MemPlace { meta: MemPlaceMeta::None, ..mplace.mplace }, layout }; - Ok((mplace, vtable)) - } - - /// Turn a `dyn* Trait` type into an value with the actual dynamic type. - /// Also returns the vtable. - pub(super) fn unpack_dyn_star<P: Projectable<'tcx, M::Provenance>>( - &self, - val: &P, - expected_trait: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>, - ) -> InterpResult<'tcx, (P, Pointer<Option<M::Provenance>>)> { - assert!( - matches!(val.layout().ty.kind(), ty::Dynamic(_, _, ty::DynStar)), - "`unpack_dyn_star` only makes sense on `dyn*` types" - ); - let data = self.project_field(val, 0)?; - let vtable = self.project_field(val, 1)?; - let vtable = self.read_pointer(&vtable.to_op(self)?)?; - let (ty, vtable_trait) = self.get_ptr_vtable(vtable)?; - if expected_trait.principal() != vtable_trait { - throw_ub!(InvalidVTableTrait { expected_trait, vtable_trait }); - } - // `data` is already the right thing but has the wrong type. So we transmute it. - let layout = self.layout_of(ty)?; - let data = data.transmute(layout, self)?; - Ok((data, vtable)) - } } // Some nodes are used a lot. Make sure they don't unintentionally get bigger. diff --git a/compiler/rustc_const_eval/src/interpret/terminator.rs b/compiler/rustc_const_eval/src/interpret/terminator.rs index cbfe25ca8df..8f76a148679 100644 --- a/compiler/rustc_const_eval/src/interpret/terminator.rs +++ b/compiler/rustc_const_eval/src/interpret/terminator.rs @@ -1,6 +1,7 @@ use std::borrow::Cow; use either::Either; +use rustc_middle::ty::TyCtxt; use tracing::trace; use rustc_middle::span_bug; @@ -827,20 +828,19 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { }; // Obtain the underlying trait we are working on, and the adjusted receiver argument. - let (vptr, dyn_ty, adjusted_receiver) = if let ty::Dynamic(data, _, ty::DynStar) = + let (dyn_trait, dyn_ty, adjusted_recv) = if let ty::Dynamic(data, _, ty::DynStar) = receiver_place.layout.ty.kind() { - let (recv, vptr) = self.unpack_dyn_star(&receiver_place, data)?; - let (dyn_ty, _dyn_trait) = self.get_ptr_vtable(vptr)?; + let recv = self.unpack_dyn_star(&receiver_place, data)?; - (vptr, dyn_ty, recv.ptr()) + (data.principal(), recv.layout.ty, recv.ptr()) } else { // Doesn't have to be a `dyn Trait`, but the unsized tail must be `dyn Trait`. // (For that reason we also cannot use `unpack_dyn_trait`.) let receiver_tail = self .tcx .struct_tail_erasing_lifetimes(receiver_place.layout.ty, self.param_env); - let ty::Dynamic(data, _, ty::Dyn) = receiver_tail.kind() else { + let ty::Dynamic(receiver_trait, _, ty::Dyn) = receiver_tail.kind() else { span_bug!( self.cur_span(), "dynamic call on non-`dyn` type {}", @@ -851,25 +851,24 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { // Get the required information from the vtable. let vptr = receiver_place.meta().unwrap_meta().to_pointer(self)?; - let (dyn_ty, dyn_trait) = self.get_ptr_vtable(vptr)?; - if dyn_trait != data.principal() { - throw_ub!(InvalidVTableTrait { - expected_trait: data, - vtable_trait: dyn_trait, - }); - } + let dyn_ty = self.get_ptr_vtable_ty(vptr, Some(receiver_trait))?; // It might be surprising that we use a pointer as the receiver even if this // is a by-val case; this works because by-val passing of an unsized `dyn // Trait` to a function is actually desugared to a pointer. - (vptr, dyn_ty, receiver_place.ptr()) + (receiver_trait.principal(), dyn_ty, receiver_place.ptr()) }; // Now determine the actual method to call. We can do that in two different ways and // compare them to ensure everything fits. - let Some(ty::VtblEntry::Method(fn_inst)) = - self.get_vtable_entries(vptr)?.get(idx).copied() - else { + let vtable_entries = if let Some(dyn_trait) = dyn_trait { + let trait_ref = dyn_trait.with_self_ty(*self.tcx, dyn_ty); + let trait_ref = self.tcx.erase_regions(trait_ref); + self.tcx.vtable_entries(trait_ref) + } else { + TyCtxt::COMMON_VTABLE_ENTRIES + }; + let Some(ty::VtblEntry::Method(fn_inst)) = vtable_entries.get(idx).copied() else { // FIXME(fee1-dead) these could be variants of the UB info enum instead of this throw_ub_custom!(fluent::const_eval_dyn_call_not_a_method); }; @@ -898,7 +897,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { let receiver_ty = Ty::new_mut_ptr(self.tcx.tcx, dyn_ty); args[0] = FnArg::Copy( ImmTy::from_immediate( - Scalar::from_maybe_pointer(adjusted_receiver, self).into(), + Scalar::from_maybe_pointer(adjusted_recv, self).into(), self.layout_of(receiver_ty)?, ) .into(), @@ -974,11 +973,11 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { let place = match place.layout.ty.kind() { ty::Dynamic(data, _, ty::Dyn) => { // Dropping a trait object. Need to find actual drop fn. - self.unpack_dyn_trait(&place, data)?.0 + self.unpack_dyn_trait(&place, data)? } ty::Dynamic(data, _, ty::DynStar) => { // Dropping a `dyn*`. Need to find actual drop fn. - self.unpack_dyn_star(&place, data)?.0 + self.unpack_dyn_star(&place, data)? } _ => { debug_assert_eq!( diff --git a/compiler/rustc_const_eval/src/interpret/traits.rs b/compiler/rustc_const_eval/src/interpret/traits.rs index 244a6ba48a4..bd2c6519421 100644 --- a/compiler/rustc_const_eval/src/interpret/traits.rs +++ b/compiler/rustc_const_eval/src/interpret/traits.rs @@ -1,11 +1,14 @@ +use rustc_infer::infer::TyCtxtInferExt; +use rustc_infer::traits::ObligationCause; use rustc_middle::mir::interpret::{InterpResult, Pointer}; use rustc_middle::ty::layout::LayoutOf; -use rustc_middle::ty::{self, Ty, TyCtxt}; +use rustc_middle::ty::{self, Ty}; use rustc_target::abi::{Align, Size}; +use rustc_trait_selection::traits::ObligationCtxt; use tracing::trace; use super::util::ensure_monomorphic_enough; -use super::{InterpCx, Machine}; +use super::{throw_ub, InterpCx, MPlaceTy, Machine, MemPlaceMeta, OffsetMode, Projectable}; impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { /// Creates a dynamic vtable for the given type and vtable origin. This is used only for @@ -33,28 +36,90 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { Ok(vtable_ptr.into()) } - /// Returns a high-level representation of the entries of the given vtable. - pub fn get_vtable_entries( - &self, - vtable: Pointer<Option<M::Provenance>>, - ) -> InterpResult<'tcx, &'tcx [ty::VtblEntry<'tcx>]> { - let (ty, poly_trait_ref) = self.get_ptr_vtable(vtable)?; - Ok(if let Some(poly_trait_ref) = poly_trait_ref { - let trait_ref = poly_trait_ref.with_self_ty(*self.tcx, ty); - let trait_ref = self.tcx.erase_regions(trait_ref); - self.tcx.vtable_entries(trait_ref) - } else { - TyCtxt::COMMON_VTABLE_ENTRIES - }) - } - pub fn get_vtable_size_and_align( &self, vtable: Pointer<Option<M::Provenance>>, + expected_trait: Option<&'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>>, ) -> InterpResult<'tcx, (Size, Align)> { - let (ty, _trait_ref) = self.get_ptr_vtable(vtable)?; + let ty = self.get_ptr_vtable_ty(vtable, expected_trait)?; let layout = self.layout_of(ty)?; assert!(layout.is_sized(), "there are no vtables for unsized types"); Ok((layout.size, layout.align.abi)) } + + /// Check that the given vtable trait is valid for a pointer/reference/place with the given + /// expected trait type. + pub(super) fn check_vtable_for_type( + &self, + vtable_trait: Option<ty::PolyExistentialTraitRef<'tcx>>, + expected_trait: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>, + ) -> InterpResult<'tcx> { + // Fast path: if they are equal, it's all fine. + if expected_trait.principal() == vtable_trait { + return Ok(()); + } + if let (Some(expected_trait), Some(vtable_trait)) = + (expected_trait.principal(), vtable_trait) + { + // Slow path: spin up an inference context to check if these traits are sufficiently equal. + let infcx = self.tcx.infer_ctxt().build(); + let ocx = ObligationCtxt::new(&infcx); + let cause = ObligationCause::dummy_with_span(self.cur_span()); + // equate the two trait refs after normalization + let expected_trait = ocx.normalize(&cause, self.param_env, expected_trait); + let vtable_trait = ocx.normalize(&cause, self.param_env, vtable_trait); + if ocx.eq(&cause, self.param_env, expected_trait, vtable_trait).is_ok() { + if ocx.select_all_or_error().is_empty() { + // All good. + return Ok(()); + } + } + } + throw_ub!(InvalidVTableTrait { expected_trait, vtable_trait }); + } + + /// Turn a place with a `dyn Trait` type into a place with the actual dynamic type. + pub(super) fn unpack_dyn_trait( + &self, + mplace: &MPlaceTy<'tcx, M::Provenance>, + expected_trait: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>, + ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::Provenance>> { + assert!( + matches!(mplace.layout.ty.kind(), ty::Dynamic(_, _, ty::Dyn)), + "`unpack_dyn_trait` only makes sense on `dyn*` types" + ); + let vtable = mplace.meta().unwrap_meta().to_pointer(self)?; + let ty = self.get_ptr_vtable_ty(vtable, Some(expected_trait))?; + // This is a kind of transmute, from a place with unsized type and metadata to + // a place with sized type and no metadata. + let layout = self.layout_of(ty)?; + let mplace = mplace.offset_with_meta( + Size::ZERO, + OffsetMode::Wrapping, + MemPlaceMeta::None, + layout, + self, + )?; + Ok(mplace) + } + + /// Turn a `dyn* Trait` type into an value with the actual dynamic type. + pub(super) fn unpack_dyn_star<P: Projectable<'tcx, M::Provenance>>( + &self, + val: &P, + expected_trait: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>, + ) -> InterpResult<'tcx, P> { + assert!( + matches!(val.layout().ty.kind(), ty::Dynamic(_, _, ty::DynStar)), + "`unpack_dyn_star` only makes sense on `dyn*` types" + ); + let data = self.project_field(val, 0)?; + let vtable = self.project_field(val, 1)?; + let vtable = self.read_pointer(&vtable.to_op(self)?)?; + let ty = self.get_ptr_vtable_ty(vtable, Some(expected_trait))?; + // `data` is already the right thing but has the wrong type. So we transmute it. + let layout = self.layout_of(ty)?; + let data = data.transmute(layout, self)?; + Ok(data) + } } diff --git a/compiler/rustc_const_eval/src/interpret/validity.rs b/compiler/rustc_const_eval/src/interpret/validity.rs index f532f6bbe37..6f75bc2af4e 100644 --- a/compiler/rustc_const_eval/src/interpret/validity.rs +++ b/compiler/rustc_const_eval/src/interpret/validity.rs @@ -343,20 +343,16 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValidityVisitor<'rt, 'tcx, M> { match tail.kind() { ty::Dynamic(data, _, ty::Dyn) => { let vtable = meta.unwrap_meta().to_pointer(self.ecx)?; - // Make sure it is a genuine vtable pointer. - let (_dyn_ty, dyn_trait) = try_validation!( - self.ecx.get_ptr_vtable(vtable), + // Make sure it is a genuine vtable pointer for the right trait. + try_validation!( + self.ecx.get_ptr_vtable_ty(vtable, Some(data)), self.path, Ub(DanglingIntPointer(..) | InvalidVTablePointer(..)) => - InvalidVTablePtr { value: format!("{vtable}") } + InvalidVTablePtr { value: format!("{vtable}") }, + Ub(InvalidVTableTrait { expected_trait, vtable_trait }) => { + InvalidMetaWrongTrait { expected_trait, vtable_trait: *vtable_trait } + }, ); - // Make sure it is for the right trait. - if dyn_trait != data.principal() { - throw_validation_failure!( - self.path, - InvalidMetaWrongTrait { expected_trait: data, vtable_trait: dyn_trait } - ); - } } ty::Slice(..) | ty::Str => { let _len = meta.unwrap_meta().to_target_usize(self.ecx)?; diff --git a/compiler/rustc_const_eval/src/interpret/visitor.rs b/compiler/rustc_const_eval/src/interpret/visitor.rs index b812e89854b..71c057e549b 100644 --- a/compiler/rustc_const_eval/src/interpret/visitor.rs +++ b/compiler/rustc_const_eval/src/interpret/visitor.rs @@ -95,7 +95,7 @@ pub trait ValueVisitor<'tcx, M: Machine<'tcx>>: Sized { // unsized values are never immediate, so we can assert_mem_place let op = v.to_op(self.ecx())?; let dest = op.assert_mem_place(); - let inner_mplace = self.ecx().unpack_dyn_trait(&dest, data)?.0; + let inner_mplace = self.ecx().unpack_dyn_trait(&dest, data)?; trace!("walk_value: dyn object layout: {:#?}", inner_mplace.layout); // recurse with the inner type return self.visit_field(v, 0, &inner_mplace.into()); @@ -104,7 +104,7 @@ pub trait ValueVisitor<'tcx, M: Machine<'tcx>>: Sized { // DynStar types. Very different from a dyn type (but strangely part of the // same variant in `TyKind`): These are pairs where the 2nd component is the // vtable, and the first component is the data (which must be ptr-sized). - let data = self.ecx().unpack_dyn_star(v, data)?.0; + let data = self.ecx().unpack_dyn_star(v, data)?; return self.visit_field(v, 0, &data); } // Slices do not need special handling here: they have `Array` field |