diff options
| -rw-r--r-- | compiler/rustc_mir_transform/src/gvn.rs | 122 |
1 files changed, 67 insertions, 55 deletions
diff --git a/compiler/rustc_mir_transform/src/gvn.rs b/compiler/rustc_mir_transform/src/gvn.rs index b19323239b6..b59b7353112 100644 --- a/compiler/rustc_mir_transform/src/gvn.rs +++ b/compiler/rustc_mir_transform/src/gvn.rs @@ -163,12 +163,6 @@ enum AggregateTy<'tcx> { Array, Tuple, Def(DefId, ty::GenericArgsRef<'tcx>), - RawPtr { - /// Needed for cast propagation. - data_pointer_ty: Ty<'tcx>, - /// The data pointer can be anything thin, so doesn't determine the output. - output_pointer_ty: Ty<'tcx>, - }, } #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)] @@ -194,6 +188,17 @@ enum Value<'tcx> { /// An aggregate value, either tuple/closure/struct/enum. /// This does not contain unions, as we cannot reason with the value. Aggregate(AggregateTy<'tcx>, VariantIdx, Vec<VnIndex>), + /// A raw pointer aggregate built from a thin pointer and metadata. + RawPtr { + /// Thin pointer component. This is field 0 in MIR. + pointer: VnIndex, + /// Metadata component. This is field 1 in MIR. + metadata: VnIndex, + /// Needed for cast propagation. + data_pointer_ty: Ty<'tcx>, + /// The data pointer can be anything thin, so doesn't determine the output. + output_pointer_ty: Ty<'tcx>, + }, /// This corresponds to a `[value; count]` expression. Repeat(VnIndex, ty::Const<'tcx>), /// The address of a place. @@ -402,22 +407,11 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { AggregateTy::Def(def_id, args) => { self.tcx.type_of(def_id).instantiate(self.tcx, args) } - AggregateTy::RawPtr { output_pointer_ty, .. } => output_pointer_ty, }; let variant = if ty.is_enum() { Some(variant) } else { None }; let ty = self.ecx.layout_of(ty).ok()?; if ty.is_zst() { ImmTy::uninit(ty).into() - } else if matches!(kind, AggregateTy::RawPtr { .. }) { - // Pointers don't have fields, so don't `project_field` them. - let data = self.ecx.read_pointer(fields[0]).discard_err()?; - let meta = if fields[1].layout.is_zst() { - MemPlaceMeta::None - } else { - MemPlaceMeta::Meta(self.ecx.read_scalar(fields[1]).discard_err()?) - }; - let ptr_imm = Immediate::new_pointer_with_meta(data, meta, &self.ecx); - ImmTy::from_immediate(ptr_imm, ty).into() } else if matches!( ty.backend_repr, BackendRepr::Scalar(..) | BackendRepr::ScalarPair(..) @@ -446,6 +440,22 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { return None; } } + RawPtr { pointer, metadata, output_pointer_ty, data_pointer_ty: _ } => { + let pointer = self.evaluated[pointer].as_ref()?; + let metadata = self.evaluated[metadata].as_ref()?; + let output_pointer_ty = self.ecx.layout_of(output_pointer_ty).ok()?; + debug_assert!(!output_pointer_ty.is_zst()); + + // Pointers don't have fields, so don't `project_field` them. + let data = self.ecx.read_pointer(pointer).discard_err()?; + let meta = if metadata.layout.is_zst() { + MemPlaceMeta::None + } else { + MemPlaceMeta::Meta(self.ecx.read_scalar(metadata).discard_err()?) + }; + let ptr_imm = Immediate::new_pointer_with_meta(data, meta, &self.ecx); + ImmTy::from_immediate(ptr_imm, output_pointer_ty).into() + } Projection(base, elem) => { let value = self.evaluated[base].as_ref()?; @@ -1026,7 +1036,12 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { } } - let (mut ty, variant_index) = match *kind { + let fields: Vec<_> = field_ops + .iter_mut() + .map(|op| self.simplify_operand(op, location).unwrap_or_else(|| self.new_opaque())) + .collect(); + + let (ty, variant_index) = match *kind { AggregateKind::Array(..) => { assert!(!field_ops.is_empty()); (AggregateTy::Array, FIRST_VARIANT) @@ -1045,41 +1060,41 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { AggregateKind::Adt(_, _, _, _, Some(_)) => return None, AggregateKind::RawPtr(pointee_ty, mtbl) => { assert_eq!(field_ops.len(), 2); - let data_pointer_ty = field_ops[FieldIdx::ZERO].ty(self.local_decls, self.tcx); + let mut data_pointer_ty = field_ops[FieldIdx::ZERO].ty(self.local_decls, self.tcx); let output_pointer_ty = Ty::new_ptr(self.tcx, pointee_ty, mtbl); - (AggregateTy::RawPtr { data_pointer_ty, output_pointer_ty }, FIRST_VARIANT) - } - }; - - let mut fields: Vec<_> = field_ops - .iter_mut() - .map(|op| self.simplify_operand(op, location).unwrap_or_else(|| self.new_opaque())) - .collect(); - if let AggregateTy::RawPtr { data_pointer_ty, output_pointer_ty } = &mut ty { - let mut was_updated = false; + let [mut pointer, metadata] = fields.try_into().unwrap(); + + // Any thin pointer of matching mutability is fine as the data pointer. + let mut was_updated = false; + while let Value::Cast { + kind: CastKind::PtrToPtr, + value: cast_value, + from: cast_from, + to: _, + } = self.get(pointer) + && let ty::RawPtr(from_pointee_ty, from_mtbl) = cast_from.kind() + && let ty::RawPtr(_, output_mtbl) = output_pointer_ty.kind() + && from_mtbl == output_mtbl + && from_pointee_ty.is_sized(self.tcx, self.typing_env()) + { + pointer = *cast_value; + data_pointer_ty = *cast_from; + was_updated = true; + } - // Any thin pointer of matching mutability is fine as the data pointer. - while let Value::Cast { - kind: CastKind::PtrToPtr, - value: cast_value, - from: cast_from, - to: _, - } = self.get(fields[0]) - && let ty::RawPtr(from_pointee_ty, from_mtbl) = cast_from.kind() - && let ty::RawPtr(_, output_mtbl) = output_pointer_ty.kind() - && from_mtbl == output_mtbl - && from_pointee_ty.is_sized(self.tcx, self.typing_env()) - { - fields[0] = *cast_value; - *data_pointer_ty = *cast_from; - was_updated = true; - } + if was_updated && let Some(op) = self.try_as_operand(pointer, location) { + field_ops[FieldIdx::ZERO] = op; + } - if was_updated && let Some(op) = self.try_as_operand(fields[0], location) { - field_ops[FieldIdx::ZERO] = op; + return Some(self.insert(Value::RawPtr { + output_pointer_ty, + data_pointer_ty, + pointer, + metadata, + })); } - } + }; if let AggregateTy::Array = ty && fields.len() > 4 @@ -1165,9 +1180,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { (UnOp::Not, Value::BinaryOp(BinOp::Ne, lhs, rhs)) => { Value::BinaryOp(BinOp::Eq, *lhs, *rhs) } - (UnOp::PtrMetadata, Value::Aggregate(AggregateTy::RawPtr { .. }, _, fields)) => { - return Some(fields[1]); - } + (UnOp::PtrMetadata, Value::RawPtr { metadata, .. }) => return Some(*metadata), // We have an unsizing cast, which assigns the length to wide pointer metadata. ( UnOp::PtrMetadata, @@ -1399,16 +1412,15 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { // If a cast just casts away the metadata again, then we can get it by // casting the original thin pointer passed to `from_raw_parts` if let PtrToPtr = kind - && let Value::Aggregate(AggregateTy::RawPtr { data_pointer_ty, .. }, _, fields) = - self.get(value) + && let Value::RawPtr { data_pointer_ty, pointer, .. } = self.get(value) && let ty::RawPtr(to_pointee, _) = to.kind() && to_pointee.is_sized(self.tcx, self.typing_env()) { from = *data_pointer_ty; - value = fields[0]; + value = *pointer; was_updated_this_iteration = true; if *data_pointer_ty == to { - return Some(fields[0]); + return Some(*pointer); } } |