diff options
Diffstat (limited to 'compiler/rustc_const_eval/src/interpret/place.rs')
| -rw-r--r-- | compiler/rustc_const_eval/src/interpret/place.rs | 191 |
1 files changed, 85 insertions, 106 deletions
diff --git a/compiler/rustc_const_eval/src/interpret/place.rs b/compiler/rustc_const_eval/src/interpret/place.rs index 274af61ee..3c463500a 100644 --- a/compiler/rustc_const_eval/src/interpret/place.rs +++ b/compiler/rustc_const_eval/src/interpret/place.rs @@ -7,8 +7,8 @@ use either::{Either, Left, Right}; use rustc_ast::Mutability; use rustc_middle::mir; use rustc_middle::ty; -use rustc_middle::ty::layout::{LayoutOf, PrimitiveExt, TyAndLayout}; -use rustc_target::abi::{self, Abi, Align, HasDataLayout, Size, TagEncoding, VariantIdx}; +use rustc_middle::ty::layout::{LayoutOf, TyAndLayout}; +use rustc_target::abi::{self, Abi, Align, HasDataLayout, Size, VariantIdx}; use super::{ alloc_range, mir_assign_valid_types, AllocId, AllocRef, AllocRefMut, CheckInAllocMsg, @@ -26,6 +26,7 @@ pub enum MemPlaceMeta<Prov: Provenance = AllocId> { } impl<Prov: Provenance> MemPlaceMeta<Prov> { + #[cfg_attr(debug_assertions, track_caller)] // only in debug builds due to perf (see #98980) pub fn unwrap_meta(self) -> Scalar<Prov> { match self { Self::Meta(s) => s, @@ -147,12 +148,16 @@ impl<Prov: Provenance> MemPlace<Prov> { } #[inline] - pub fn offset_with_meta<'tcx>( + pub(super) fn offset_with_meta<'tcx>( self, offset: Size, meta: MemPlaceMeta<Prov>, cx: &impl HasDataLayout, ) -> InterpResult<'tcx, Self> { + debug_assert!( + !meta.has_meta() || self.meta.has_meta(), + "cannot use `offset_with_meta` to add metadata to a place" + ); Ok(MemPlace { ptr: self.ptr.offset(offset, cx)?, meta }) } } @@ -178,12 +183,15 @@ impl<'tcx, Prov: Provenance> MPlaceTy<'tcx, Prov> { pub fn fake_alloc_zst(layout: TyAndLayout<'tcx>) -> Self { assert!(layout.is_zst()); let align = layout.align.abi; - let ptr = Pointer::from_addr(align.bytes()); // no provenance, absolute address + let ptr = Pointer::from_addr_invalid(align.bytes()); // no provenance, absolute address MPlaceTy { mplace: MemPlace { ptr, meta: MemPlaceMeta::None }, layout, align } } + /// Offset the place in memory and change its metadata. + /// + /// This can go wrong very easily if you give the wrong layout for the new place! #[inline] - pub fn offset_with_meta( + pub(crate) fn offset_with_meta( &self, offset: Size, meta: MemPlaceMeta<Prov>, @@ -197,6 +205,9 @@ impl<'tcx, Prov: Provenance> MPlaceTy<'tcx, Prov> { }) } + /// Offset the place in memory. + /// + /// This can go wrong very easily if you give the wrong layout for the new place! pub fn offset( &self, offset: Size, @@ -229,7 +240,7 @@ impl<'tcx, Prov: Provenance> MPlaceTy<'tcx, Prov> { if self.layout.is_unsized() { // We need to consult `meta` metadata match self.layout.ty.kind() { - ty::Slice(..) | ty::Str => self.mplace.meta.unwrap_meta().to_machine_usize(cx), + ty::Slice(..) | ty::Str => self.mplace.meta.unwrap_meta().to_target_usize(cx), _ => bug!("len not supported on unsized type {:?}", self.layout.ty), } } else { @@ -241,14 +252,6 @@ impl<'tcx, Prov: Provenance> MPlaceTy<'tcx, Prov> { } } } - - #[inline] - pub(super) fn vtable(&self) -> Scalar<Prov> { - match self.layout.ty.kind() { - ty::Dynamic(..) => self.mplace.meta.unwrap_meta(), - _ => bug!("vtable not supported on type {:?}", self.layout.ty), - } - } } // These are defined here because they produce a place. @@ -266,7 +269,12 @@ impl<'tcx, Prov: Provenance> OpTy<'tcx, Prov> { #[inline(always)] #[cfg_attr(debug_assertions, track_caller)] // only in debug builds due to perf (see #98980) pub fn assert_mem_place(&self) -> MPlaceTy<'tcx, Prov> { - self.as_mplace_or_imm().left().unwrap() + self.as_mplace_or_imm().left().unwrap_or_else(|| { + bug!( + "OpTy of type {} was immediate when it was expected to be an MPlace", + self.layout.ty + ) + }) } } @@ -283,7 +291,12 @@ impl<'tcx, Prov: Provenance> PlaceTy<'tcx, Prov> { #[inline(always)] #[cfg_attr(debug_assertions, track_caller)] // only in debug builds due to perf (see #98980) pub fn assert_mem_place(&self) -> MPlaceTy<'tcx, Prov> { - self.as_mplace_or_local().left().unwrap() + self.as_mplace_or_local().left().unwrap_or_else(|| { + bug!( + "PlaceTy of type {} was a local when it was expected to be an MPlace", + self.layout.ty + ) + }) } } @@ -340,7 +353,8 @@ where pub(super) fn get_place_alloc( &self, place: &MPlaceTy<'tcx, M::Provenance>, - ) -> InterpResult<'tcx, Option<AllocRef<'_, 'tcx, M::Provenance, M::AllocExtra>>> { + ) -> InterpResult<'tcx, Option<AllocRef<'_, 'tcx, M::Provenance, M::AllocExtra, M::Bytes>>> + { assert!(place.layout.is_sized()); assert!(!place.meta.has_meta()); let size = place.layout.size; @@ -351,7 +365,8 @@ where pub(super) fn get_place_alloc_mut( &mut self, place: &MPlaceTy<'tcx, M::Provenance>, - ) -> InterpResult<'tcx, Option<AllocRefMut<'_, 'tcx, M::Provenance, M::AllocExtra>>> { + ) -> InterpResult<'tcx, Option<AllocRefMut<'_, 'tcx, M::Provenance, M::AllocExtra, M::Bytes>>> + { assert!(place.layout.is_sized()); assert!(!place.meta.has_meta()); let size = place.layout.size; @@ -754,9 +769,9 @@ where str: &str, kind: MemoryKind<M::MemoryKind>, mutbl: Mutability, - ) -> MPlaceTy<'tcx, M::Provenance> { - let ptr = self.allocate_bytes_ptr(str.as_bytes(), Align::ONE, kind, mutbl); - let meta = Scalar::from_machine_usize(u64::try_from(str.len()).unwrap(), self); + ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::Provenance>> { + let ptr = self.allocate_bytes_ptr(str.as_bytes(), Align::ONE, kind, mutbl)?; + let meta = Scalar::from_target_usize(u64::try_from(str.len()).unwrap(), self); let mplace = MemPlace { ptr: ptr.into(), meta: MemPlaceMeta::Meta(meta) }; let ty = self.tcx.mk_ref( @@ -764,95 +779,35 @@ where ty::TypeAndMut { ty: self.tcx.types.str_, mutbl }, ); let layout = self.layout_of(ty).unwrap(); - MPlaceTy { mplace, layout, align: layout.align.abi } + Ok(MPlaceTy { mplace, layout, align: layout.align.abi }) } - /// Writes the discriminant of the given variant. - #[instrument(skip(self), level = "debug")] - pub fn write_discriminant( + /// Writes the aggregate to the destination. + #[instrument(skip(self), level = "trace")] + pub fn write_aggregate( &mut self, - variant_index: VariantIdx, + kind: &mir::AggregateKind<'tcx>, + operands: &[mir::Operand<'tcx>], dest: &PlaceTy<'tcx, M::Provenance>, ) -> InterpResult<'tcx> { - // This must be an enum or generator. - match dest.layout.ty.kind() { - ty::Adt(adt, _) => assert!(adt.is_enum()), - ty::Generator(..) => {} - _ => span_bug!( - self.cur_span(), - "write_discriminant called on non-variant-type (neither enum nor generator)" - ), - } - // Layout computation excludes uninhabited variants from consideration - // therefore there's no way to represent those variants in the given layout. - // Essentially, uninhabited variants do not have a tag that corresponds to their - // discriminant, so we cannot do anything here. - // When evaluating we will always error before even getting here, but ConstProp 'executes' - // dead code, so we cannot ICE here. - if dest.layout.for_variant(self, variant_index).abi.is_uninhabited() { - throw_ub!(UninhabitedEnumVariantWritten) - } - - match dest.layout.variants { - abi::Variants::Single { index } => { - assert_eq!(index, variant_index); - } - abi::Variants::Multiple { - tag_encoding: TagEncoding::Direct, - tag: tag_layout, - tag_field, - .. - } => { - // No need to validate that the discriminant here because the - // `TyAndLayout::for_variant()` call earlier already checks the variant is valid. - - let discr_val = - dest.layout.ty.discriminant_for_variant(*self.tcx, variant_index).unwrap().val; - - // raw discriminants for enums are isize or bigger during - // their computation, but the in-memory tag is the smallest possible - // representation - let size = tag_layout.size(self); - let tag_val = size.truncate(discr_val); - - let tag_dest = self.place_field(dest, tag_field)?; - self.write_scalar(Scalar::from_uint(tag_val, size), &tag_dest)?; - } - abi::Variants::Multiple { - tag_encoding: - TagEncoding::Niche { untagged_variant, ref niche_variants, niche_start }, - tag: tag_layout, - tag_field, - .. - } => { - // No need to validate that the discriminant here because the - // `TyAndLayout::for_variant()` call earlier already checks the variant is valid. - - if variant_index != untagged_variant { - let variants_start = niche_variants.start().as_u32(); - let variant_index_relative = variant_index - .as_u32() - .checked_sub(variants_start) - .expect("overflow computing relative variant idx"); - // We need to use machine arithmetic when taking into account `niche_start`: - // tag_val = variant_index_relative + niche_start_val - let tag_layout = self.layout_of(tag_layout.primitive().to_int_ty(*self.tcx))?; - let niche_start_val = ImmTy::from_uint(niche_start, tag_layout); - let variant_index_relative_val = - ImmTy::from_uint(variant_index_relative, tag_layout); - let tag_val = self.binary_op( - mir::BinOp::Add, - &variant_index_relative_val, - &niche_start_val, - )?; - // Write result. - let niche_dest = self.place_field(dest, tag_field)?; - self.write_immediate(*tag_val, &niche_dest)?; - } + self.write_uninit(&dest)?; + let (variant_index, variant_dest, active_field_index) = match *kind { + mir::AggregateKind::Adt(_, variant_index, _, _, active_field_index) => { + let variant_dest = self.place_downcast(&dest, variant_index)?; + (variant_index, variant_dest, active_field_index) } + _ => (VariantIdx::from_u32(0), dest.clone(), None), + }; + if active_field_index.is_some() { + assert_eq!(operands.len(), 1); } - - Ok(()) + for (field_index, operand) in operands.iter().enumerate() { + let field_index = active_field_index.unwrap_or(field_index); + let field_dest = self.place_field(&variant_dest, field_index)?; + let op = self.eval_operand(operand, Some(field_dest.layout))?; + self.copy_op(&op, &field_dest, /*allow_transmute*/ false)?; + } + self.write_discriminant(variant_index, &dest) } pub fn raw_const_to_mplace( @@ -867,11 +822,16 @@ where } /// 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>, - ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::Provenance>> { - let vtable = mplace.vtable().to_pointer(self)?; // also sanity checks the type + ) -> 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, _) = self.get_ptr_vtable(vtable)?; let layout = self.layout_of(ty)?; @@ -880,7 +840,26 @@ where layout, align: layout.align.abi, }; - Ok(mplace) + Ok((mplace, vtable)) + } + + /// Turn an operand with a `dyn* Trait` type into an operand with the actual dynamic type. + /// Aso returns the vtable. + pub(super) fn unpack_dyn_star( + &self, + op: &OpTy<'tcx, M::Provenance>, + ) -> InterpResult<'tcx, (OpTy<'tcx, M::Provenance>, Pointer<Option<M::Provenance>>)> { + assert!( + matches!(op.layout.ty.kind(), ty::Dynamic(_, _, ty::DynStar)), + "`unpack_dyn_star` only makes sense on `dyn*` types" + ); + let data = self.operand_field(&op, 0)?; + let vtable = self.operand_field(&op, 1)?; + let vtable = self.read_pointer(&vtable)?; + let (ty, _) = self.get_ptr_vtable(vtable)?; + let layout = self.layout_of(ty)?; + let data = data.transmute(layout); + Ok((data, vtable)) } } |