diff --git a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs index 7cca6178ab2..38fecf7232e 100644 --- a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs +++ b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs @@ -106,6 +106,7 @@ pub(super) fn mk_eval_cx<'mir, 'tcx>( /// This function converts an interpreter value into a constant that is meant for use in the /// type system. +#[instrument(skip(ecx), level = "debug")] pub(super) fn op_to_const<'tcx>( ecx: &CompileTimeEvalContext<'_, 'tcx>, op: &OpTy<'tcx>, @@ -140,21 +141,26 @@ pub(super) fn op_to_const<'tcx>( op.try_as_mplace() }; + debug!(?immediate); + // We know `offset` is relative to the allocation, so we can use `into_parts`. - let to_const_value = |mplace: &MPlaceTy<'_>| match mplace.ptr.into_parts() { - (Some(alloc_id), offset) => { - let alloc = ecx.tcx.global_alloc(alloc_id).unwrap_memory(); - ConstValue::ByRef { alloc, offset } - } - (None, offset) => { - assert!(mplace.layout.is_zst()); - assert_eq!( - offset.bytes() % mplace.layout.align.abi.bytes(), - 0, - "this MPlaceTy must come from a validated constant, thus we can assume the \ + let to_const_value = |mplace: &MPlaceTy<'_>| { + debug!("to_const_value(mplace: {:?})", mplace); + match mplace.ptr.into_parts() { + (Some(alloc_id), offset) => { + let alloc = ecx.tcx.global_alloc(alloc_id).unwrap_memory(); + ConstValue::ByRef { alloc, offset } + } + (None, offset) => { + assert!(mplace.layout.is_zst()); + assert_eq!( + offset.bytes() % mplace.layout.align.abi.bytes(), + 0, + "this MPlaceTy must come from a validated constant, thus we can assume the \ alignment is correct", - ); - ConstValue::Scalar(Scalar::ZST) + ); + ConstValue::Scalar(Scalar::ZST) + } } }; match immediate { @@ -166,6 +172,7 @@ pub(super) fn op_to_const<'tcx>( ScalarMaybeUninit::Uninit => to_const_value(&op.assert_mem_place()), }, Immediate::ScalarPair(a, b) => { + debug!("ScalarPair(a: {:?}, b: {:?})", a, b); // We know `offset` is relative to the allocation, so we can use `into_parts`. let (data, start) = match ecx.scalar_to_ptr(a.check_init().unwrap()).unwrap().into_parts() { @@ -209,7 +216,10 @@ fn turn_into_const_value<'tcx>( ); // Turn this into a proper constant. - op_to_const(&ecx, &mplace.into()) + let const_val = op_to_const(&ecx, &mplace.into()); + debug!(?const_val); + + const_val } pub fn eval_to_const_value_raw_provider<'tcx>( diff --git a/compiler/rustc_const_eval/src/const_eval/mod.rs b/compiler/rustc_const_eval/src/const_eval/mod.rs index 68f9bee593f..96c18d488ee 100644 --- a/compiler/rustc_const_eval/src/const_eval/mod.rs +++ b/compiler/rustc_const_eval/src/const_eval/mod.rs @@ -3,29 +3,26 @@ use std::convert::TryFrom; use rustc_hir::Mutability; -use rustc_middle::ty::layout::HasTyCtxt; +use rustc_middle::mir; use rustc_middle::ty::{self, TyCtxt}; -use rustc_middle::{ - mir::{self, interpret::ConstAlloc}, - ty::ScalarInt, -}; use rustc_span::{source_map::DUMMY_SP, symbol::Symbol}; -use rustc_target::abi::VariantIdx; use crate::interpret::{ - intern_const_alloc_recursive, ConstValue, InternKind, InterpCx, InterpResult, MPlaceTy, - MemPlaceMeta, Scalar, + intern_const_alloc_recursive, ConstValue, InternKind, InterpCx, InterpResult, MemPlaceMeta, + Scalar, }; mod error; mod eval_queries; mod fn_queries; mod machine; +mod valtrees; pub use error::*; pub use eval_queries::*; pub use fn_queries::*; pub use machine::*; +pub(crate) use valtrees::{const_to_valtree, valtree_to_const_value}; pub(crate) fn const_caller_location( tcx: TyCtxt<'_>, @@ -41,128 +38,6 @@ pub(crate) fn const_caller_location( ConstValue::Scalar(Scalar::from_maybe_pointer(loc_place.ptr, &tcx)) } -/// Convert an evaluated constant to a type level constant -pub(crate) fn const_to_valtree<'tcx>( - tcx: TyCtxt<'tcx>, - param_env: ty::ParamEnv<'tcx>, - raw: ConstAlloc<'tcx>, -) -> Option> { - let ecx = mk_eval_cx( - tcx, DUMMY_SP, param_env, - // It is absolutely crucial for soundness that - // we do not read from static items or other mutable memory. - false, - ); - let place = ecx.raw_const_to_mplace(raw).unwrap(); - const_to_valtree_inner(&ecx, &place) -} - -#[instrument(skip(ecx), level = "debug")] -fn branches<'tcx>( - ecx: &CompileTimeEvalContext<'tcx, 'tcx>, - place: &MPlaceTy<'tcx>, - n: usize, - variant: Option, -) -> Option> { - let place = match variant { - Some(variant) => ecx.mplace_downcast(&place, variant).unwrap(), - None => *place, - }; - let variant = variant.map(|variant| Some(ty::ValTree::Leaf(ScalarInt::from(variant.as_u32())))); - debug!(?place, ?variant); - - let fields = (0..n).map(|i| { - let field = ecx.mplace_field(&place, i).unwrap(); - const_to_valtree_inner(ecx, &field) - }); - // For enums, we prepend their variant index before the variant's fields so we can figure out - // the variant again when just seeing a valtree. - let branches = variant.into_iter().chain(fields); - Some(ty::ValTree::Branch(ecx.tcx.arena.alloc_from_iter(branches.collect::>>()?))) -} - -fn slice_branches<'tcx>( - ecx: &CompileTimeEvalContext<'tcx, 'tcx>, - place: &MPlaceTy<'tcx>, -) -> Option> { - let n = place.len(&ecx.tcx()).expect(&format!("expected to use len of place {:?}", place)); - let branches = (0..n).map(|i| { - let place_elem = ecx.mplace_index(place, i).unwrap(); - const_to_valtree_inner(ecx, &place_elem) - }); - - Some(ty::ValTree::Branch(ecx.tcx.arena.alloc_from_iter(branches.collect::>>()?))) -} - -#[instrument(skip(ecx), level = "debug")] -fn const_to_valtree_inner<'tcx>( - ecx: &CompileTimeEvalContext<'tcx, 'tcx>, - place: &MPlaceTy<'tcx>, -) -> Option> { - match place.layout.ty.kind() { - ty::FnDef(..) => Some(ty::ValTree::zst()), - ty::Bool | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Char => { - let val = ecx.read_immediate(&place.into()).unwrap(); - let val = val.to_scalar().unwrap(); - Some(ty::ValTree::Leaf(val.assert_int())) - } - - // Raw pointers are not allowed in type level constants, as we cannot properly test them for - // equality at compile-time (see `ptr_guaranteed_eq`/`_ne`). - // Technically we could allow function pointers (represented as `ty::Instance`), but this is not guaranteed to - // agree with runtime equality tests. - ty::FnPtr(_) | ty::RawPtr(_) => None, - - ty::Ref(_, _, _) => { - let derefd_place = ecx.deref_operand(&place.into()).unwrap_or_else(|e| bug!("couldn't deref {:?}, error: {:?}", place, e)); - debug!(?derefd_place); - - const_to_valtree_inner(ecx, &derefd_place) - } - - ty::Str | ty::Slice(_) | ty::Array(_, _) => { - let valtree = slice_branches(ecx, place); - debug!(?valtree); - - valtree - } - // Trait objects are not allowed in type level constants, as we have no concept for - // resolving their backing type, even if we can do that at const eval time. We may - // hypothetically be able to allow `dyn StructuralEq` trait objects in the future, - // but it is unclear if this is useful. - ty::Dynamic(..) => None, - - ty::Tuple(substs) => branches(ecx, place, substs.len(), None), - - ty::Adt(def, _) => { - if def.variants().is_empty() { - bug!("uninhabited types should have errored and never gotten converted to valtree") - } - - let variant = ecx.read_discriminant(&place.into()).unwrap().1; - - branches(ecx, place, def.variant(variant).fields.len(), def.is_enum().then_some(variant)) - } - - ty::Never - | ty::Error(_) - | ty::Foreign(..) - | ty::Infer(ty::FreshIntTy(_)) - | ty::Infer(ty::FreshFloatTy(_)) - | ty::Projection(..) - | ty::Param(_) - | ty::Bound(..) - | ty::Placeholder(..) - // FIXME(oli-obk): we could look behind opaque types - | ty::Opaque(..) - | ty::Infer(_) - // FIXME(oli-obk): we can probably encode closures just like structs - | ty::Closure(..) - | ty::Generator(..) - | ty::GeneratorWitness(..) => None, - } -} - /// This function should never fail for validated constants. However, it is also invoked from the /// pretty printer which might attempt to format invalid constants and in that case it might fail. pub(crate) fn try_destructure_const<'tcx>( @@ -202,6 +77,7 @@ pub(crate) fn try_destructure_const<'tcx>( Ok(mir::DestructuredConst { variant, fields }) } +#[instrument(skip(tcx), level = "debug")] pub(crate) fn deref_const<'tcx>( tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>, diff --git a/compiler/rustc_const_eval/src/const_eval/valtrees.rs b/compiler/rustc_const_eval/src/const_eval/valtrees.rs new file mode 100644 index 00000000000..374179d0cc2 --- /dev/null +++ b/compiler/rustc_const_eval/src/const_eval/valtrees.rs @@ -0,0 +1,459 @@ +use super::eval_queries::{mk_eval_cx, op_to_const}; +use super::machine::CompileTimeEvalContext; +use crate::interpret::{ + intern_const_alloc_recursive, ConstValue, ImmTy, Immediate, InternKind, MemPlaceMeta, + MemoryKind, PlaceTy, Scalar, ScalarMaybeUninit, +}; +use rustc_middle::mir::interpret::ConstAlloc; +use rustc_middle::ty::{self, ScalarInt, Ty, TyCtxt}; +use rustc_span::source_map::DUMMY_SP; +use rustc_target::abi::{Align, VariantIdx}; + +use crate::interpret::MPlaceTy; +use crate::interpret::Value; + +/// Convert an evaluated constant to a type level constant +#[instrument(skip(tcx), level = "debug")] +pub(crate) fn const_to_valtree<'tcx>( + tcx: TyCtxt<'tcx>, + param_env: ty::ParamEnv<'tcx>, + raw: ConstAlloc<'tcx>, +) -> Option> { + let ecx = mk_eval_cx( + tcx, DUMMY_SP, param_env, + // It is absolutely crucial for soundness that + // we do not read from static items or other mutable memory. + false, + ); + let place = ecx.raw_const_to_mplace(raw).unwrap(); + const_to_valtree_inner(&ecx, &place) +} + +#[instrument(skip(ecx), level = "debug")] +fn branches<'tcx>( + ecx: &CompileTimeEvalContext<'tcx, 'tcx>, + place: &MPlaceTy<'tcx>, + n: usize, + variant: Option, +) -> Option> { + let place = match variant { + Some(variant) => ecx.mplace_downcast(&place, variant).unwrap(), + None => *place, + }; + let variant = variant.map(|variant| Some(ty::ValTree::Leaf(ScalarInt::from(variant.as_u32())))); + debug!(?place, ?variant); + + let fields = (0..n).map(|i| { + let field = ecx.mplace_field(&place, i).unwrap(); + const_to_valtree_inner(ecx, &field) + }); + // For enums, we preped their variant index before the variant's fields so we can figure out + // the variant again when just seeing a valtree. + let branches = variant.into_iter().chain(fields); + Some(ty::ValTree::Branch(ecx.tcx.arena.alloc_from_iter(branches.collect::>>()?))) +} + +#[instrument(skip(ecx), level = "debug")] +fn slice_branches<'tcx>( + ecx: &CompileTimeEvalContext<'tcx, 'tcx>, + place: &MPlaceTy<'tcx>, +) -> Option> { + let n = place.len(&ecx.tcx.tcx).expect(&format!("expected to use len of place {:?}", place)); + let branches = (0..n).map(|i| { + let place_elem = ecx.mplace_index(place, i).unwrap(); + const_to_valtree_inner(ecx, &place_elem) + }); + + Some(ty::ValTree::Branch(ecx.tcx.arena.alloc_from_iter(branches.collect::>>()?))) +} + +#[instrument(skip(ecx), level = "debug")] +fn const_to_valtree_inner<'tcx>( + ecx: &CompileTimeEvalContext<'tcx, 'tcx>, + place: &MPlaceTy<'tcx>, +) -> Option> { + match place.layout.ty.kind() { + ty::FnDef(..) => Some(ty::ValTree::zst()), + ty::Bool | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Char => { + let val = ecx.read_immediate(&place.into()).unwrap(); + let val = val.to_scalar().unwrap(); + Some(ty::ValTree::Leaf(val.assert_int())) + } + + // Raw pointers are not allowed in type level constants, as we cannot properly test them for + // equality at compile-time (see `ptr_guaranteed_eq`/`_ne`). + // Technically we could allow function pointers (represented as `ty::Instance`), but this is not guaranteed to + // agree with runtime equality tests. + ty::FnPtr(_) | ty::RawPtr(_) => None, + + ty::Ref(_, _, _) => { + let derefd_place = ecx.deref_operand(&place.into()).unwrap_or_else(|e| bug!("couldn't deref {:?}, error: {:?}", place, e)); + debug!(?derefd_place); + + const_to_valtree_inner(ecx, &derefd_place) + } + + ty::Str | ty::Slice(_) | ty::Array(_, _) => { + let valtree = slice_branches(ecx, place); + debug!(?valtree); + + valtree + } + // Trait objects are not allowed in type level constants, as we have no concept for + // resolving their backing type, even if we can do that at const eval time. We may + // hypothetically be able to allow `dyn StructuralEq` trait objects in the future, + // but it is unclear if this is useful. + ty::Dynamic(..) => None, + + ty::Tuple(substs) => branches(ecx, place, substs.len(), None), + + ty::Adt(def, _) => { + if def.is_union() { + return None + } else if def.variants().is_empty() { + bug!("uninhabited types should have errored and never gotten converted to valtree") + } + + let variant = ecx.read_discriminant(&place.into()).unwrap().1; + + branches(ecx, place, def.variant(variant).fields.len(), def.is_enum().then_some(variant)) + } + + ty::Never + | ty::Error(_) + | ty::Foreign(..) + | ty::Infer(ty::FreshIntTy(_)) + | ty::Infer(ty::FreshFloatTy(_)) + | ty::Projection(..) + | ty::Param(_) + | ty::Bound(..) + | ty::Placeholder(..) + // FIXME(oli-obk): we could look behind opaque types + | ty::Opaque(..) + | ty::Infer(_) + // FIXME(oli-obk): we can probably encode closures just like structs + | ty::Closure(..) + | ty::Generator(..) + | ty::GeneratorWitness(..) => None, + } +} + +#[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>, + valtree: ty::ValTree<'tcx>, + tcx: TyCtxt<'tcx>, +) -> (Ty<'tcx>, usize) { + let mut last_valtree = valtree; + let tail = tcx.struct_tail_with_normalize( + ty, + |ty| ty, + || { + let branches = last_valtree.unwrap_branch(); + last_valtree = branches[branches.len() - 1]; + 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.mk_ty(ty::Uint(ty::UintTy::U8)), + _ => unsized_inner_ty, + }; + + // Get the number of elements in the unsized field + let num_elems = last_valtree.unwrap_branch().len(); + + (unsized_inner_ty, num_elems) +} + +#[instrument(skip(ecx), level = "debug")] +fn create_pointee_place<'tcx>( + ecx: &mut CompileTimeEvalContext<'tcx, '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.mk_ty(ty::Uint(ty::UintTy::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 ptr = ecx + .allocate_ptr( + size_of_sized_part.checked_add(dst_size, &tcx).unwrap(), + Align::from_bytes(1).unwrap(), + MemoryKind::Stack, + ) + .unwrap(); + debug!(?ptr); + + let mut place = MPlaceTy::from_aligned_ptr(ptr.into(), layout); + place.meta = MemPlaceMeta::Meta(Scalar::from_u64(num_elems as u64)); + debug!(?place); + + place + } else { + create_mplace_from_layout(ecx, ty) + } +} + +/// Converts a `ValTree` to a `ConstValue`, which is needed after mir +/// construction has finished. +// FIXME Merge `valtree_to_const_value` and `fill_place_recursively` into one function +#[instrument(skip(tcx), level = "debug")] +pub fn valtree_to_const_value<'tcx>( + tcx: TyCtxt<'tcx>, + param_env_ty: ty::ParamEnvAnd<'tcx, Ty<'tcx>>, + valtree: ty::ValTree<'tcx>, +) -> ConstValue<'tcx> { + // Basic idea: We directly construct `Scalar` values from trivial `ValTree`s + // (those for constants with type bool, int, uint, float or char). + // For all other types we create an `MPlace` and fill that by walking + // the `ValTree` and using `place_projection` and `place_field` to + // create inner `MPlace`s which are filled recursively. + // FIXME Does this need an example? + + let (param_env, ty) = param_env_ty.into_parts(); + let mut ecx = mk_eval_cx(tcx, DUMMY_SP, param_env, false); + + match ty.kind() { + ty::FnDef(..) => { + assert!(valtree.unwrap_branch().is_empty()); + ConstValue::Scalar(Scalar::ZST) + } + ty::Bool | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Char => match valtree { + ty::ValTree::Leaf(scalar_int) => ConstValue::Scalar(Scalar::Int(scalar_int)), + ty::ValTree::Branch(_) => bug!( + "ValTrees for Bool, Int, Uint, Float or Char should have the form ValTree::Leaf" + ), + }, + ty::Ref(_, _, _) | ty::Tuple(_) | ty::Array(_, _) | ty::Adt(..) => { + let mut place = match ty.kind() { + ty::Ref(_, inner_ty, _) => { + // Need to create a place for the pointee to fill for Refs + create_pointee_place(&mut ecx, *inner_ty, valtree) + } + _ => create_mplace_from_layout(&mut ecx, ty), + }; + debug!(?place); + + fill_place_recursively(&mut ecx, &mut place, valtree); + dump_place(&ecx, place.into()); + intern_const_alloc_recursive(&mut ecx, InternKind::Constant, &place).unwrap(); + + let const_val = match ty.kind() { + ty::Ref(_, _, _) => { + let ref_place = place.to_ref(&tcx); + let imm = + ImmTy::from_immediate(ref_place, tcx.layout_of(param_env_ty).unwrap()); + + op_to_const(&ecx, &imm.into()) + } + _ => op_to_const(&ecx, &place.into()), + }; + debug!(?const_val); + + const_val + } + ty::Never + | ty::Error(_) + | ty::Foreign(..) + | ty::Infer(ty::FreshIntTy(_)) + | ty::Infer(ty::FreshFloatTy(_)) + | ty::Projection(..) + | ty::Param(_) + | ty::Bound(..) + | ty::Placeholder(..) + | ty::Opaque(..) + | ty::Infer(_) + | ty::Closure(..) + | ty::Generator(..) + | ty::GeneratorWitness(..) + | ty::FnPtr(_) + | ty::RawPtr(_) + | ty::Str + | ty::Slice(_) + | ty::Dynamic(..) => bug!("no ValTree should have been created for type {:?}", ty.kind()), + } +} + +// FIXME Needs a better/correct name +#[instrument(skip(ecx), level = "debug")] +fn fill_place_recursively<'tcx>( + ecx: &mut CompileTimeEvalContext<'tcx, 'tcx>, + place: &mut MPlaceTy<'tcx>, + valtree: ty::ValTree<'tcx>, +) { + // This will match on valtree and write the value(s) corresponding to the ValTree + // inside the place recursively. + + let tcx = ecx.tcx.tcx; + let ty = place.layout.ty; + + match ty.kind() { + ty::FnDef(_, _) => { + ecx.write_immediate( + Immediate::Scalar(ScalarMaybeUninit::Scalar(Scalar::ZST)), + &(*place).into(), + ) + .unwrap(); + } + ty::Bool | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Char => { + let scalar_int = valtree.unwrap_leaf(); + debug!("writing trivial valtree {:?} to place {:?}", scalar_int, place); + ecx.write_immediate( + Immediate::Scalar(ScalarMaybeUninit::Scalar(scalar_int.into())), + &(*place).into(), + ) + .unwrap(); + } + ty::Ref(_, inner_ty, _) => { + let mut pointee_place = create_pointee_place(ecx, *inner_ty, valtree); + debug!(?pointee_place); + + fill_place_recursively(ecx, &mut pointee_place, valtree); + dump_place(ecx, pointee_place.into()); + intern_const_alloc_recursive(ecx, InternKind::Constant, &pointee_place).unwrap(); + + let imm = match inner_ty.kind() { + ty::Slice(_) | ty::Str => { + let len = valtree.unwrap_branch().len(); + let len_scalar = ScalarMaybeUninit::Scalar(Scalar::from_u64(len as u64)); + + Immediate::ScalarPair( + ScalarMaybeUninit::from_maybe_pointer((*pointee_place).ptr, &tcx), + len_scalar, + ) + } + _ => pointee_place.to_ref(&tcx), + }; + debug!(?imm); + + ecx.write_immediate(imm, &(*place).into()).unwrap(); + } + ty::Adt(_, _) | ty::Tuple(_) | ty::Array(_, _) | ty::Str | ty::Slice(_) => { + let branches = valtree.unwrap_branch(); + + // Need to downcast place for enums + let (place_adjusted, branches, variant_idx) = match ty.kind() { + ty::Adt(def, _) if def.is_enum() => { + // First element of valtree corresponds to variant + let scalar_int = branches[0].unwrap_leaf(); + let variant_idx = VariantIdx::from_u32(scalar_int.try_to_u32().unwrap()); + let variant = def.variant(variant_idx); + debug!(?variant); + + ( + place.project_downcast(ecx, variant_idx).unwrap(), + &branches[1..], + Some(variant_idx), + ) + } + _ => (*place, branches, None), + }; + debug!(?place_adjusted, ?branches); + + // Create the places (by indexing into `place`) for the fields and fill + // them recursively + for (i, inner_valtree) in branches.iter().enumerate() { + debug!(?i, ?inner_valtree); + + let mut place_inner = match ty.kind() { + ty::Str | ty::Slice(_) => ecx.mplace_index(&place, i as u64).unwrap(), + _ if !ty.is_sized(ecx.tcx, ty::ParamEnv::empty()) + && i == branches.len() - 1 => + { + // Note: For custom DSTs we need to manually process the last unsized field. + // We created a `Pointer` for the `Allocation` of the complete sized version of + // the Adt in `create_pointee_place` and now we fill that `Allocation` with the + // values in the ValTree. For the unsized field we have to additionally add the meta + // data. + + let (unsized_inner_ty, num_elems) = + get_info_on_unsized_field(ty, valtree, tcx); + debug!(?unsized_inner_ty); + + let inner_ty = match ty.kind() { + ty::Adt(def, substs) => { + def.variant(VariantIdx::from_u32(0)).fields[i].ty(tcx, substs) + } + ty::Tuple(inner_tys) => inner_tys[i], + _ => bug!("unexpected unsized type {:?}", ty), + }; + + let inner_layout = + tcx.layout_of(ty::ParamEnv::empty().and(inner_ty)).unwrap(); + debug!(?inner_layout); + + let offset = place_adjusted.layout.fields.offset(i); + place + .offset( + offset, + MemPlaceMeta::Meta(Scalar::from_u64(num_elems as u64)), + inner_layout, + &tcx, + ) + .unwrap() + } + _ => ecx.mplace_field(&place_adjusted, i).unwrap(), + }; + + debug!(?place_inner); + fill_place_recursively(ecx, &mut place_inner, *inner_valtree); + dump_place(&ecx, place_inner.into()); + } + + debug!("dump of place_adjusted:"); + dump_place(ecx, place_adjusted.into()); + + if let Some(variant_idx) = variant_idx { + // don't forget filling the place with the discriminant of the enum + ecx.write_discriminant(variant_idx, &(*place).into()).unwrap(); + } + + debug!("dump of place after writing discriminant:"); + dump_place(ecx, (*place).into()); + } + _ => bug!("shouldn't have created a ValTree for {:?}", ty), + } +} + +fn dump_place<'tcx>(ecx: &CompileTimeEvalContext<'tcx, 'tcx>, place: PlaceTy<'tcx>) { + trace!("{:?}", ecx.dump_place(*place)); +} diff --git a/compiler/rustc_const_eval/src/interpret/mod.rs b/compiler/rustc_const_eval/src/interpret/mod.rs index 2b9fe565997..69d6c8470a2 100644 --- a/compiler/rustc_const_eval/src/interpret/mod.rs +++ b/compiler/rustc_const_eval/src/interpret/mod.rs @@ -27,7 +27,7 @@ pub use self::memory::{AllocCheck, AllocRef, AllocRefMut, FnVal, Memory, MemoryK pub use self::operand::{ImmTy, Immediate, OpTy, Operand}; pub use self::place::{MPlaceTy, MemPlace, MemPlaceMeta, Place, PlaceTy}; pub use self::validity::{CtfeValidationMode, RefTracking}; -pub use self::visitor::{MutValueVisitor, ValueVisitor}; +pub use self::visitor::{MutValueVisitor, Value, ValueVisitor}; crate use self::intrinsics::eval_nullary_intrinsic; use eval_context::{from_known_layout, mir_assign_valid_types}; diff --git a/compiler/rustc_const_eval/src/interpret/operand.rs b/compiler/rustc_const_eval/src/interpret/operand.rs index dfc0028e87f..f2d833b3202 100644 --- a/compiler/rustc_const_eval/src/interpret/operand.rs +++ b/compiler/rustc_const_eval/src/interpret/operand.rs @@ -424,6 +424,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { }) } + #[instrument(skip(self), level = "debug")] pub fn operand_projection( &self, base: &OpTy<'tcx, M::PointerTag>, diff --git a/compiler/rustc_const_eval/src/interpret/place.rs b/compiler/rustc_const_eval/src/interpret/place.rs index e4660fe090c..380eb526361 100644 --- a/compiler/rustc_const_eval/src/interpret/place.rs +++ b/compiler/rustc_const_eval/src/interpret/place.rs @@ -115,6 +115,12 @@ impl<'tcx, Tag: Provenance> std::ops::Deref for MPlaceTy<'tcx, Tag> { } } +impl<'tcx, Tag: Provenance> std::ops::DerefMut for MPlaceTy<'tcx, Tag> { + fn deref_mut(&mut self) -> &mut Self::Target { + &mut self.mplace + } +} + impl<'tcx, Tag: Provenance> From> for PlaceTy<'tcx, Tag> { #[inline(always)] fn from(mplace: MPlaceTy<'tcx, Tag>) -> Self { @@ -294,6 +300,7 @@ where /// Take an operand, representing a pointer, and dereference it to a place -- that /// will always be a MemPlace. Lives in `place.rs` because it creates a place. + #[instrument(skip(self), level = "debug")] pub fn deref_operand( &self, src: &OpTy<'tcx, M::PointerTag>, @@ -487,7 +494,8 @@ where } /// Project into an mplace - pub(super) fn mplace_projection( + #[instrument(skip(self), level = "debug")] + pub(crate) fn mplace_projection( &self, base: &MPlaceTy<'tcx, M::PointerTag>, proj_elem: mir::PlaceElem<'tcx>, @@ -548,6 +556,7 @@ where /// Just a convenience function, but used quite a bit. /// This is the only projection that might have a side-effect: We cannot project /// into the field of a local `ScalarPair`, we have to first allocate it. + #[instrument(skip(self), level = "debug")] pub fn place_field( &mut self, base: &PlaceTy<'tcx, M::PointerTag>, @@ -617,6 +626,7 @@ where /// Computes a place. You should only use this if you intend to write into this /// place; for reading, a more efficient alternative is `eval_place_for_read`. + #[instrument(skip(self), level = "debug")] pub fn eval_place( &mut self, place: mir::Place<'tcx>, @@ -646,6 +656,7 @@ where /// Write an immediate to a place #[inline(always)] + #[instrument(skip(self), level = "debug")] pub fn write_immediate( &mut self, src: Immediate, @@ -830,6 +841,7 @@ where /// Copies the data from an operand to a place. This does not support transmuting! /// Use `copy_op_transmute` if the layouts could disagree. #[inline(always)] + #[instrument(skip(self), level = "debug")] pub fn copy_op( &mut self, src: &OpTy<'tcx, M::PointerTag>, @@ -849,6 +861,7 @@ where /// Use `copy_op_transmute` if the layouts could disagree. /// Also, if you use this you are responsible for validating that things get copied at the /// right type. + #[instrument(skip(self), level = "debug")] fn copy_op_no_validate( &mut self, src: &OpTy<'tcx, M::PointerTag>, @@ -955,6 +968,7 @@ where /// This supports unsized types and returns the computed size to avoid some /// redundant computation when copying; use `force_allocation` for a simpler, sized-only /// version. + #[instrument(skip(self), level = "debug")] pub fn force_allocation_maybe_sized( &mut self, place: &PlaceTy<'tcx, M::PointerTag>, @@ -1037,6 +1051,7 @@ where } /// Writes the discriminant of the given variant. + #[instrument(skip(self), level = "debug")] pub fn write_discriminant( &mut self, variant_index: VariantIdx, diff --git a/compiler/rustc_const_eval/src/lib.rs b/compiler/rustc_const_eval/src/lib.rs index d688331ae0a..34a00452519 100644 --- a/compiler/rustc_const_eval/src/lib.rs +++ b/compiler/rustc_const_eval/src/lib.rs @@ -35,6 +35,7 @@ pub mod transform; pub mod util; use rustc_middle::ty::query::Providers; +use rustc_middle::ty::ParamEnv; pub fn provide(providers: &mut Providers) { const_eval::provide(providers); @@ -49,6 +50,9 @@ pub fn provide(providers: &mut Providers) { let (param_env, raw) = param_env_and_value.into_parts(); const_eval::const_to_valtree(tcx, param_env, raw) }; + providers.valtree_to_const_val = |tcx, (ty, valtree)| { + const_eval::valtree_to_const_value(tcx, ParamEnv::empty().and(ty), valtree) + }; providers.deref_const = |tcx, param_env_and_value| { let (param_env, value) = param_env_and_value.into_parts(); const_eval::deref_const(tcx, param_env, value) diff --git a/compiler/rustc_middle/src/mir/interpret/allocation.rs b/compiler/rustc_middle/src/mir/interpret/allocation.rs index c628406064f..8cfc5ed0a95 100644 --- a/compiler/rustc_middle/src/mir/interpret/allocation.rs +++ b/compiler/rustc_middle/src/mir/interpret/allocation.rs @@ -418,6 +418,7 @@ impl Allocation { /// /// It is the caller's responsibility to check bounds and alignment beforehand. /// Most likely, you want to call `InterpCx::write_scalar` instead of this method. + #[instrument(skip(self, cx), level = "debug")] pub fn write_scalar( &mut self, cx: &impl HasDataLayout, diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs index d8586a8a77d..cc80ab8f16e 100644 --- a/compiler/rustc_middle/src/query/mod.rs +++ b/compiler/rustc_middle/src/query/mod.rs @@ -936,6 +936,11 @@ rustc_queries! { remap_env_constness } + /// Converts a type level constant value into `ConstValue` + query valtree_to_const_val(key: (Ty<'tcx>, ty::ValTree<'tcx>)) -> ConstValue<'tcx> { + desc { "convert type-level constant value to mir constant value"} + } + /// Destructure a constant ADT or array into its variant index and its /// field values or return `None` if constant is invalid. /// diff --git a/compiler/rustc_middle/src/ty/consts/int.rs b/compiler/rustc_middle/src/ty/consts/int.rs index 72623ba54ee..a3ce674c115 100644 --- a/compiler/rustc_middle/src/ty/consts/int.rs +++ b/compiler/rustc_middle/src/ty/consts/int.rs @@ -237,6 +237,98 @@ impl ScalarInt { pub fn try_to_machine_usize<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Result { Ok(self.to_bits(tcx.data_layout.pointer_size)? as u64) } + + /// Tries to convert the `ScalarInt` to an unsigned integer of the given size. + /// Fails if the size of the `ScalarInt` is unequal to `size` and returns the + /// `ScalarInt`s size in that case. + #[inline] + pub fn try_to_uint(self, size: Size) -> Result { + self.to_bits(size) + } + + // Tries to convert the `ScalarInt` to `u8`. Fails if the `size` of the `ScalarInt` + // in not equal to `Size { raw: 1 }` and returns the `size` value of the `ScalarInt` in + // that case. + #[inline] + pub fn try_to_u8(self) -> Result { + self.to_bits(Size::from_bits(8)).map(|v| u8::try_from(v).unwrap()) + } + + /// Tries to convert the `ScalarInt` to `u16`. Fails if the size of the `ScalarInt` + /// in not equal to `Size { raw: 2 }` and returns the `size` value of the `ScalarInt` in + /// that case. + #[inline] + pub fn try_to_u16(self) -> Result { + self.to_bits(Size::from_bits(16)).map(|v| u16::try_from(v).unwrap()) + } + + /// Tries to convert the `ScalarInt` to `u32`. Fails if the `size` of the `ScalarInt` + /// in not equal to `Size { raw: 4 }` and returns the `size` value of the `ScalarInt` in + /// that case. + #[inline] + pub fn try_to_u32(self) -> Result { + self.to_bits(Size::from_bits(32)).map(|v| u32::try_from(v).unwrap()) + } + + /// Tries to convert the `ScalarInt` to `u64`. Fails if the `size` of the `ScalarInt` + /// in not equal to `Size { raw: 8 }` and returns the `size` value of the `ScalarInt` in + /// that case. + #[inline] + pub fn try_to_u64(self) -> Result { + self.to_bits(Size::from_bits(64)).map(|v| u64::try_from(v).unwrap()) + } + + /// Tries to convert the `ScalarInt` to `u128`. Fails if the `size` of the `ScalarInt` + /// in not equal to `Size { raw: 16 }` and returns the `size` value of the `ScalarInt` in + /// that case. + #[inline] + pub fn try_to_u128(self) -> Result { + self.to_bits(Size::from_bits(128)) + } + + /// Tries to convert the `ScalarInt` to a signed integer of the given size. + /// Fails if the size of the `ScalarInt` is unequal to `size` and returns the + /// `ScalarInt`s size in that case. + #[inline] + pub fn try_to_int(self, size: Size) -> Result { + let b = self.to_bits(size)?; + Ok(size.sign_extend(b) as i128) + } + + /// Tries to convert the `ScalarInt` to i8. + /// Fails if the size of the `ScalarInt` is unequal to `Size { raw: 1 }` + /// and returns the `ScalarInt`s size in that case. + pub fn try_to_i8(self) -> Result { + self.try_to_int(Size::from_bits(8)).map(|v| i8::try_from(v).unwrap()) + } + + /// Tries to convert the `ScalarInt` to i16. + /// Fails if the size of the `ScalarInt` is unequal to `Size { raw: 2 }` + /// and returns the `ScalarInt`s size in that case. + pub fn try_to_i16(self) -> Result { + self.try_to_int(Size::from_bits(16)).map(|v| i16::try_from(v).unwrap()) + } + + /// Tries to convert the `ScalarInt` to i32. + /// Fails if the size of the `ScalarInt` is unequal to `Size { raw: 4 }` + /// and returns the `ScalarInt`s size in that case. + pub fn try_to_i32(self) -> Result { + self.try_to_int(Size::from_bits(32)).map(|v| i32::try_from(v).unwrap()) + } + + /// Tries to convert the `ScalarInt` to i64. + /// Fails if the size of the `ScalarInt` is unequal to `Size { raw: 8 }` + /// and returns the `ScalarInt`s size in that case. + pub fn try_to_i64(self) -> Result { + self.try_to_int(Size::from_bits(64)).map(|v| i64::try_from(v).unwrap()) + } + + /// Tries to convert the `ScalarInt` to i128. + /// Fails if the size of the `ScalarInt` is unequal to `Size { raw: 16 }` + /// and returns the `ScalarInt`s size in that case. + pub fn try_to_i128(self) -> Result { + self.try_to_int(Size::from_bits(128)).map(|v| i128::try_from(v).unwrap()) + } } macro_rules! from { diff --git a/compiler/rustc_middle/src/ty/consts/valtree.rs b/compiler/rustc_middle/src/ty/consts/valtree.rs index 195760c0590..418848f69d7 100644 --- a/compiler/rustc_middle/src/ty/consts/valtree.rs +++ b/compiler/rustc_middle/src/ty/consts/valtree.rs @@ -20,6 +20,9 @@ pub enum ValTree<'tcx> { /// See the `ScalarInt` documentation for how `ScalarInt` guarantees that equal values /// of these types have the same representation. Leaf(ScalarInt), + + //SliceOrStr(ValSlice<'tcx>), + // dont use SliceOrStr for now /// The fields of any kind of aggregate. Structs, tuples and arrays are represented by /// listing their fields' values in order. /// Enums are represented by storing their discriminant as a field, followed by all @@ -31,4 +34,20 @@ impl<'tcx> ValTree<'tcx> { pub fn zst() -> Self { Self::Branch(&[]) } + + #[inline] + pub fn unwrap_leaf(self) -> ScalarInt { + match self { + Self::Leaf(s) => s, + _ => bug!("expected leaf, got {:?}", self), + } + } + + #[inline] + pub fn unwrap_branch(self) -> &'tcx [Self] { + match self { + Self::Branch(branch) => branch, + _ => bug!("expected branch, got {:?}", self), + } + } } diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs index 5a13216846d..1509de0e930 100644 --- a/compiler/rustc_middle/src/ty/sty.rs +++ b/compiler/rustc_middle/src/ty/sty.rs @@ -2273,7 +2273,7 @@ impl<'tcx> Ty<'tcx> { tcx: TyCtxt<'tcx>, normalize: impl FnMut(Ty<'tcx>) -> Ty<'tcx>, ) -> (Ty<'tcx>, bool) { - let tail = tcx.struct_tail_with_normalize(self, normalize); + let tail = tcx.struct_tail_with_normalize(self, normalize, || {}); match tail.kind() { // Sized types ty::Infer(ty::IntVar(_) | ty::FloatVar(_)) diff --git a/compiler/rustc_middle/src/ty/util.rs b/compiler/rustc_middle/src/ty/util.rs index 39038e85b11..918fe49e8e3 100644 --- a/compiler/rustc_middle/src/ty/util.rs +++ b/compiler/rustc_middle/src/ty/util.rs @@ -187,7 +187,7 @@ impl<'tcx> TyCtxt<'tcx> { /// if input `ty` is not a structure at all. pub fn struct_tail_without_normalization(self, ty: Ty<'tcx>) -> Ty<'tcx> { let tcx = self; - tcx.struct_tail_with_normalize(ty, |ty| ty) + tcx.struct_tail_with_normalize(ty, |ty| ty, || {}) } /// Returns the deeply last field of nested structures, or the same type if @@ -203,7 +203,7 @@ impl<'tcx> TyCtxt<'tcx> { param_env: ty::ParamEnv<'tcx>, ) -> Ty<'tcx> { let tcx = self; - tcx.struct_tail_with_normalize(ty, |ty| tcx.normalize_erasing_regions(param_env, ty)) + tcx.struct_tail_with_normalize(ty, |ty| tcx.normalize_erasing_regions(param_env, ty), || {}) } /// Returns the deeply last field of nested structures, or the same type if @@ -220,6 +220,10 @@ impl<'tcx> TyCtxt<'tcx> { self, mut ty: Ty<'tcx>, mut normalize: impl FnMut(Ty<'tcx>) -> Ty<'tcx>, + // This is currently used to allow us to walk a ValTree + // in lockstep with the type in order to get the ValTree branch that + // corresponds to an unsized field. + mut f: impl FnMut() -> (), ) -> Ty<'tcx> { let recursion_limit = self.recursion_limit(); for iteration in 0.. { @@ -235,12 +239,16 @@ impl<'tcx> TyCtxt<'tcx> { break; } match def.non_enum_variant().fields.last() { - Some(f) => ty = f.ty(self, substs), + Some(field) => { + f(); + ty = field.ty(self, substs); + } None => break, } } ty::Tuple(tys) if let Some((&last_ty, _)) = tys.split_last() => { + f(); ty = last_ty; } diff --git a/compiler/rustc_query_impl/src/keys.rs b/compiler/rustc_query_impl/src/keys.rs index f1f83a7299c..3f0f856b5dd 100644 --- a/compiler/rustc_query_impl/src/keys.rs +++ b/compiler/rustc_query_impl/src/keys.rs @@ -502,3 +502,14 @@ impl<'tcx> Key for (ty::Instance<'tcx>, &'tcx ty::List>) { self.0.default_span(tcx) } } + +impl<'tcx> Key for (Ty<'tcx>, ty::ValTree<'tcx>) { + #[inline(always)] + fn query_crate_is_local(&self) -> bool { + true + } + + fn default_span(&self, _: TyCtxt<'_>) -> Span { + DUMMY_SP + } +} diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs index 8ba390c71db..c7a61cbe25a 100644 --- a/compiler/rustc_trait_selection/src/traits/project.rs +++ b/compiler/rustc_trait_selection/src/traits/project.rs @@ -1519,18 +1519,22 @@ fn assemble_candidates_from_impls<'cx, 'tcx>( // Any type with multiple potential metadata types is therefore not eligible. let self_ty = selcx.infcx().shallow_resolve(obligation.predicate.self_ty()); - let tail = selcx.tcx().struct_tail_with_normalize(self_ty, |ty| { - // We throw away any obligations we get from this, since we normalize - // and confirm these obligations once again during confirmation - normalize_with_depth( - selcx, - obligation.param_env, - obligation.cause.clone(), - obligation.recursion_depth + 1, - ty, - ) - .value - }); + let tail = selcx.tcx().struct_tail_with_normalize( + self_ty, + |ty| { + // We throw away any obligations we get from this, since we normalize + // and confirm these obligations once again during confirmation + normalize_with_depth( + selcx, + obligation.param_env, + obligation.cause.clone(), + obligation.recursion_depth + 1, + ty, + ) + .value + }, + || {}, + ); match tail.kind() { ty::Bool