From 134d8190727c6dca40011f03686e7bb68f46a26b Mon Sep 17 00:00:00 2001 From: Camille GILLOT Date: Wed, 25 Jan 2023 18:34:19 +0000 Subject: [PATCH] Stop deaggegating MIR. --- .../rustc_const_eval/src/util/aggregate.rs | 77 ------------------- compiler/rustc_const_eval/src/util/mod.rs | 2 - .../rustc_mir_transform/src/deaggregator.rs | 49 ------------ compiler/rustc_mir_transform/src/lib.rs | 4 - 4 files changed, 132 deletions(-) delete mode 100644 compiler/rustc_const_eval/src/util/aggregate.rs delete mode 100644 compiler/rustc_mir_transform/src/deaggregator.rs diff --git a/compiler/rustc_const_eval/src/util/aggregate.rs b/compiler/rustc_const_eval/src/util/aggregate.rs deleted file mode 100644 index 10783c5ed1d..00000000000 --- a/compiler/rustc_const_eval/src/util/aggregate.rs +++ /dev/null @@ -1,77 +0,0 @@ -use rustc_index::vec::Idx; -use rustc_middle::mir::*; -use rustc_middle::ty::{Ty, TyCtxt}; -use rustc_target::abi::VariantIdx; - -use std::iter::TrustedLen; - -/// Expand `lhs = Rvalue::Aggregate(kind, operands)` into assignments to the fields. -/// -/// Produces something like -/// ```ignore (ilustrative) -/// (lhs as Variant).field0 = arg0; // We only have a downcast if this is an enum -/// (lhs as Variant).field1 = arg1; -/// discriminant(lhs) = variant_index; // If lhs is an enum or generator. -/// ``` -pub fn expand_aggregate<'tcx>( - orig_lhs: Place<'tcx>, - operands: impl Iterator, Ty<'tcx>)> + TrustedLen, - kind: AggregateKind<'tcx>, - source_info: SourceInfo, - tcx: TyCtxt<'tcx>, -) -> impl Iterator> + TrustedLen { - let mut lhs = orig_lhs; - let mut set_discriminant = None; - let active_field_index = match kind { - AggregateKind::Adt(adt_did, variant_index, _, _, active_field_index) => { - let adt_def = tcx.adt_def(adt_did); - if adt_def.is_enum() { - set_discriminant = Some(Statement { - kind: StatementKind::SetDiscriminant { - place: Box::new(orig_lhs), - variant_index, - }, - source_info, - }); - lhs = tcx.mk_place_downcast(orig_lhs, adt_def, variant_index); - } - active_field_index - } - AggregateKind::Generator(..) => { - // Right now we only support initializing generators to - // variant 0 (Unresumed). - let variant_index = VariantIdx::new(0); - set_discriminant = Some(Statement { - kind: StatementKind::SetDiscriminant { place: Box::new(orig_lhs), variant_index }, - source_info, - }); - - // Operands are upvars stored on the base place, so no - // downcast is necessary. - - None - } - _ => None, - }; - - let operands = operands.enumerate().map(move |(i, (op, ty))| { - let lhs_field = if let AggregateKind::Array(_) = kind { - let offset = u64::try_from(i).unwrap(); - tcx.mk_place_elem( - lhs, - ProjectionElem::ConstantIndex { offset, min_length: offset + 1, from_end: false }, - ) - } else { - let field = Field::new(active_field_index.unwrap_or(i)); - tcx.mk_place_field(lhs, field, ty) - }; - Statement { - source_info, - kind: StatementKind::Assign(Box::new((lhs_field, Rvalue::Use(op)))), - } - }); - [Statement { source_info, kind: StatementKind::Deinit(Box::new(orig_lhs)) }] - .into_iter() - .chain(operands) - .chain(set_discriminant) -} diff --git a/compiler/rustc_const_eval/src/util/mod.rs b/compiler/rustc_const_eval/src/util/mod.rs index 76ea5a24e69..51735e33e0f 100644 --- a/compiler/rustc_const_eval/src/util/mod.rs +++ b/compiler/rustc_const_eval/src/util/mod.rs @@ -1,4 +1,3 @@ -pub mod aggregate; mod alignment; mod call_kind; pub mod collect_writes; @@ -7,7 +6,6 @@ mod find_self_call; mod might_permit_raw_init; mod type_name; -pub use self::aggregate::expand_aggregate; pub use self::alignment::is_disaligned; pub use self::call_kind::{call_kind, CallDesugaringKind, CallKind}; pub use self::compare_types::{is_equal_up_to_subtyping, is_subtype}; diff --git a/compiler/rustc_mir_transform/src/deaggregator.rs b/compiler/rustc_mir_transform/src/deaggregator.rs deleted file mode 100644 index 905e127b7cb..00000000000 --- a/compiler/rustc_mir_transform/src/deaggregator.rs +++ /dev/null @@ -1,49 +0,0 @@ -use crate::util::expand_aggregate; -use crate::MirPass; -use rustc_hir::def::DefKind; -use rustc_middle::mir::*; -use rustc_middle::ty::TyCtxt; - -pub struct Deaggregator; - -impl<'tcx> MirPass<'tcx> for Deaggregator { - fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { - let basic_blocks = body.basic_blocks.as_mut_preserves_cfg(); - for bb in basic_blocks { - bb.expand_statements(|stmt| { - // FIXME(eddyb) don't match twice on `stmt.kind` (post-NLL). - let StatementKind::Assign(box ( - _, Rvalue::Aggregate(box ref kind, _)) - ) = stmt.kind else { return None }; - - // FIXME(#48193) Deaggregate arrays when it's cheaper to do so. - if let AggregateKind::Array(_) = kind { - return None; - } - - if let AggregateKind::Adt(def_id, ..) = kind - && matches!(tcx.def_kind(def_id), DefKind::Enum) - { - return None; - } - - let stmt = stmt.replace_nop(); - let source_info = stmt.source_info; - let StatementKind::Assign(box (lhs, Rvalue::Aggregate(kind, operands))) = stmt.kind else { - bug!(); - }; - - Some(expand_aggregate( - lhs, - operands.into_iter().map(|op| { - let ty = op.ty(&body.local_decls, tcx); - (op, ty) - }), - *kind, - source_info, - tcx, - )) - }); - } - } -} diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs index 6815289776e..9070a7368b1 100644 --- a/compiler/rustc_mir_transform/src/lib.rs +++ b/compiler/rustc_mir_transform/src/lib.rs @@ -60,7 +60,6 @@ mod coverage; mod ctfe_limit; mod dataflow_const_prop; mod dead_store_elimination; -mod deaggregator; mod deduce_param_attrs; mod deduplicate_blocks; mod deref_separator; @@ -523,9 +522,6 @@ fn run_runtime_lowering_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { &elaborate_box_derefs::ElaborateBoxDerefs, &generator::StateTransform, &add_retag::AddRetag, - // Deaggregator is necessary for const prop. We may want to consider implementing - // CTFE support for aggregates. - &deaggregator::Deaggregator, &Lint(const_prop_lint::ConstProp), ]; pm::run_passes_no_validate(tcx, body, passes, Some(MirPhase::Runtime(RuntimePhase::Initial)));