diff options
| -rw-r--r-- | compiler/rustc_const_eval/src/const_eval/valtrees.rs | 99 | ||||
| -rw-r--r-- | compiler/rustc_const_eval/src/interpret/place.rs | 16 | ||||
| -rw-r--r-- | compiler/rustc_const_eval/src/interpret/terminator.rs | 10 |
3 files changed, 43 insertions, 82 deletions
diff --git a/compiler/rustc_const_eval/src/const_eval/valtrees.rs b/compiler/rustc_const_eval/src/const_eval/valtrees.rs index ea72e4bb92d..b15a65d67a3 100644 --- a/compiler/rustc_const_eval/src/const_eval/valtrees.rs +++ b/compiler/rustc_const_eval/src/const_eval/valtrees.rs @@ -7,9 +7,10 @@ use crate::interpret::{ intern_const_alloc_recursive, ConstValue, ImmTy, Immediate, InternKind, MemPlaceMeta, MemoryKind, Place, Projectable, Scalar, }; +use rustc_middle::ty::layout::{LayoutOf, TyAndLayout}; use rustc_middle::ty::{self, ScalarInt, Ty, TyCtxt}; use rustc_span::source_map::DUMMY_SP; -use rustc_target::abi::{Align, VariantIdx}; +use rustc_target::abi::VariantIdx; #[instrument(skip(ecx), level = "debug")] fn branches<'tcx>( @@ -154,52 +155,37 @@ pub(crate) fn const_to_valtree_inner<'tcx>( } } -#[instrument(skip(ecx), level = "debug")] -fn create_mplace_from_layout<'tcx>( - ecx: &mut CompileTimeEvalContext<'tcx, 'tcx>, - ty: Ty<'tcx>, -) -> MPlaceTy<'tcx> { - let tcx = ecx.tcx; - let param_env = ecx.param_env; - let layout = tcx.layout_of(param_env.and(ty)).unwrap(); - debug!(?layout); - - ecx.allocate(layout, MemoryKind::Stack).unwrap() -} - -// Walks custom DSTs and gets the type of the unsized field and the number of elements -// in the unsized field. -fn get_info_on_unsized_field<'tcx>( - ty: Ty<'tcx>, +/// Valtrees don't store the `MemPlaceMeta` that all dynamically sized values have in the interpreter. +/// This function reconstructs it. +fn reconstruct_place_meta<'tcx>( + layout: TyAndLayout<'tcx>, valtree: ty::ValTree<'tcx>, tcx: TyCtxt<'tcx>, -) -> (Ty<'tcx>, usize) { +) -> MemPlaceMeta { + if layout.is_sized() { + return MemPlaceMeta::None; + } + let mut last_valtree = valtree; + // Traverse the type, and update `last_valtree` as we go. let tail = tcx.struct_tail_with_normalize( - ty, + layout.ty, |ty| ty, || { let branches = last_valtree.unwrap_branch(); - last_valtree = branches[branches.len() - 1]; + last_valtree = *branches.last().unwrap(); debug!(?branches, ?last_valtree); }, ); - let unsized_inner_ty = match tail.kind() { - ty::Slice(t) => *t, - ty::Str => tail, - _ => bug!("expected Slice or Str"), - }; - - // Have to adjust type for ty::Str - let unsized_inner_ty = match unsized_inner_ty.kind() { - ty::Str => tcx.types.u8, - _ => unsized_inner_ty, + // Sanity-check that we got a tail we support. + match tail.kind() { + ty::Slice(..) | ty::Str => {} + _ => bug!("unsized tail of a valtree must be Slice or Str"), }; - // Get the number of elements in the unsized field + // Get the number of elements in the unsized field. let num_elems = last_valtree.unwrap_branch().len(); - - (unsized_inner_ty, num_elems) + MemPlaceMeta::Meta(Scalar::from_target_usize(num_elems as u64, &tcx)) } #[instrument(skip(ecx), level = "debug", ret)] @@ -208,41 +194,9 @@ fn create_pointee_place<'tcx>( ty: Ty<'tcx>, valtree: ty::ValTree<'tcx>, ) -> MPlaceTy<'tcx> { - let tcx = ecx.tcx.tcx; - - if !ty.is_sized(*ecx.tcx, ty::ParamEnv::empty()) { - // We need to create `Allocation`s for custom DSTs - - let (unsized_inner_ty, num_elems) = get_info_on_unsized_field(ty, valtree, tcx); - let unsized_inner_ty = match unsized_inner_ty.kind() { - ty::Str => tcx.types.u8, - _ => unsized_inner_ty, - }; - let unsized_inner_ty_size = - tcx.layout_of(ty::ParamEnv::empty().and(unsized_inner_ty)).unwrap().layout.size(); - debug!(?unsized_inner_ty, ?unsized_inner_ty_size, ?num_elems); - - // for custom DSTs only the last field/element is unsized, but we need to also allocate - // space for the other fields/elements - let layout = tcx.layout_of(ty::ParamEnv::empty().and(ty)).unwrap(); - let size_of_sized_part = layout.layout.size(); - - // Get the size of the memory behind the DST - let dst_size = unsized_inner_ty_size.checked_mul(num_elems as u64, &tcx).unwrap(); - - let size = size_of_sized_part.checked_add(dst_size, &tcx).unwrap(); - let align = Align::from_bytes(size.bytes().next_power_of_two()).unwrap(); - let ptr = ecx.allocate_ptr(size, align, MemoryKind::Stack).unwrap(); - debug!(?ptr); - - MPlaceTy::from_aligned_ptr_with_meta( - ptr.into(), - layout, - MemPlaceMeta::Meta(Scalar::from_target_usize(num_elems as u64, &tcx)), - ) - } else { - create_mplace_from_layout(ecx, ty) - } + let layout = ecx.layout_of(ty).unwrap(); + let meta = reconstruct_place_meta(layout, valtree, ecx.tcx.tcx); + ecx.allocate_dyn(layout, MemoryKind::Stack, meta).unwrap() } /// Converts a `ValTree` to a `ConstValue`, which is needed after mir @@ -282,10 +236,13 @@ pub fn valtree_to_const_value<'tcx>( ty::Ref(_, _, _) | ty::Tuple(_) | ty::Array(_, _) | ty::Adt(..) => { let place = match ty.kind() { ty::Ref(_, inner_ty, _) => { - // Need to create a place for the pointee to fill for Refs + // Need to create a place for the pointee (the reference itself will be an immediate) create_pointee_place(&mut ecx, *inner_ty, valtree) } - _ => create_mplace_from_layout(&mut ecx, ty), + _ => { + // Need to create a place for this valtree. + create_pointee_place(&mut ecx, ty, valtree) + } }; debug!(?place); diff --git a/compiler/rustc_const_eval/src/interpret/place.rs b/compiler/rustc_const_eval/src/interpret/place.rs index 2dc856528f5..a82c9566bc4 100644 --- a/compiler/rustc_const_eval/src/interpret/place.rs +++ b/compiler/rustc_const_eval/src/interpret/place.rs @@ -934,14 +934,26 @@ where Ok(MPlaceTy { mplace, layout: place.layout, align: place.align }) } + pub fn allocate_dyn( + &mut self, + layout: TyAndLayout<'tcx>, + kind: MemoryKind<M::MemoryKind>, + meta: MemPlaceMeta<M::Provenance>, + ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::Provenance>> { + let Some((size, align)) = self.size_and_align_of(&meta, &layout)? else { + span_bug!(self.cur_span(), "cannot allocate space for `extern` type, size is not known") + }; + let ptr = self.allocate_ptr(size, align, kind)?; + Ok(MPlaceTy::from_aligned_ptr_with_meta(ptr.into(), layout, meta)) + } + pub fn allocate( &mut self, layout: TyAndLayout<'tcx>, kind: MemoryKind<M::MemoryKind>, ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::Provenance>> { assert!(layout.is_sized()); - let ptr = self.allocate_ptr(layout.size, layout.align.abi, kind)?; - Ok(MPlaceTy::from_aligned_ptr(ptr.into(), layout)) + self.allocate_dyn(layout, kind, MemPlaceMeta::None) } /// Returns a wide MPlace of type `&'static [mut] str` to a new 1-aligned allocation. diff --git a/compiler/rustc_const_eval/src/interpret/terminator.rs b/compiler/rustc_const_eval/src/interpret/terminator.rs index 1bd21473182..3c03172bbef 100644 --- a/compiler/rustc_const_eval/src/interpret/terminator.rs +++ b/compiler/rustc_const_eval/src/interpret/terminator.rs @@ -393,15 +393,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { )); assert_eq!(dest_offset, None); // Allocate enough memory to hold `src`. - let Some((size, align)) = self.size_and_align_of_mplace(&src)? else { - span_bug!( - self.cur_span(), - "unsized fn arg with `extern` type tail should not be allowed" - ) - }; - let ptr = self.allocate_ptr(size, align, MemoryKind::Stack)?; - let dest_place = - MPlaceTy::from_aligned_ptr_with_meta(ptr.into(), callee_arg.layout, src.meta); + let dest_place = self.allocate_dyn(src.layout, MemoryKind::Stack, src.meta)?; // Update the local to be that new place. *M::access_local_mut(self, dest_frame, dest_local)? = Operand::Indirect(*dest_place); } |