diff options
Diffstat (limited to 'compiler/rustc_mir_dataflow/src/impls/initialized.rs')
| -rw-r--r-- | compiler/rustc_mir_dataflow/src/impls/initialized.rs | 137 |
1 files changed, 79 insertions, 58 deletions
diff --git a/compiler/rustc_mir_dataflow/src/impls/initialized.rs b/compiler/rustc_mir_dataflow/src/impls/initialized.rs index 9fdbbb1578e..d5982b9cba2 100644 --- a/compiler/rustc_mir_dataflow/src/impls/initialized.rs +++ b/compiler/rustc_mir_dataflow/src/impls/initialized.rs @@ -1,20 +1,45 @@ use std::assert_matches::assert_matches; +use rustc_abi::VariantIdx; use rustc_index::Idx; use rustc_index::bit_set::{BitSet, MixedBitSet}; use rustc_middle::bug; use rustc_middle::mir::{self, Body, CallReturnPlaces, Location, TerminatorEdges}; +use rustc_middle::ty::util::Discr; use rustc_middle::ty::{self, TyCtxt}; use tracing::{debug, instrument}; use crate::elaborate_drops::DropFlagState; -use crate::framework::SwitchIntEdgeEffects; +use crate::framework::SwitchIntTarget; use crate::move_paths::{HasMoveData, InitIndex, InitKind, LookupResult, MoveData, MovePathIndex}; use crate::{ Analysis, GenKill, MaybeReachable, drop_flag_effects, drop_flag_effects_for_function_entry, drop_flag_effects_for_location, on_all_children_bits, on_lookup_result_bits, }; +// Used by both `MaybeInitializedPlaces` and `MaybeUninitializedPlaces`. +pub struct MaybePlacesSwitchIntData<'tcx> { + enum_place: mir::Place<'tcx>, + discriminants: Vec<(VariantIdx, Discr<'tcx>)>, + index: usize, +} + +impl<'tcx> MaybePlacesSwitchIntData<'tcx> { + // The discriminant order in the `SwitchInt` targets should match the order yielded by + // `AdtDef::discriminants`. We rely on this to match each discriminant in the targets to its + // corresponding variant in linear time. + fn next_discr(&mut self, value: u128) -> VariantIdx { + // An out-of-bounds abort will occur if the discriminant ordering isn't as described above. + loop { + let (variant, discr) = self.discriminants[self.index]; + self.index += 1; + if discr.val == value { + return variant; + } + } + } +} + /// `MaybeInitializedPlaces` tracks all places that might be /// initialized upon reaching a particular point in the control flow /// for a function. @@ -247,6 +272,8 @@ impl<'tcx> Analysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> { /// We use a mixed bitset to avoid paying too high a memory footprint. type Domain = MaybeReachable<MixedBitSet<MovePathIndex>>; + type SwitchIntData = MaybePlacesSwitchIntData<'tcx>; + const NAME: &'static str = "maybe_init"; fn bottom_value(&self, _: &mir::Body<'tcx>) -> Self::Domain { @@ -328,46 +355,42 @@ impl<'tcx> Analysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> { }); } - fn apply_switch_int_edge_effects( + fn get_switch_int_data( &mut self, block: mir::BasicBlock, discr: &mir::Operand<'tcx>, - edge_effects: &mut impl SwitchIntEdgeEffects<Self::Domain>, - ) { + ) -> Option<Self::SwitchIntData> { if !self.tcx.sess.opts.unstable_opts.precise_enum_drop_elaboration { - return; + return None; } - let enum_ = discr.place().and_then(|discr| { - switch_on_enum_discriminant(self.tcx, self.body, &self.body[block], discr) - }); - - let Some((enum_place, enum_def)) = enum_ else { - return; - }; - - let mut discriminants = enum_def.discriminants(self.tcx); - edge_effects.apply(|state, edge| { - let Some(value) = edge.value else { - return; - }; - - // MIR building adds discriminants to the `values` array in the same order as they - // are yielded by `AdtDef::discriminants`. We rely on this to match each - // discriminant in `values` to its corresponding variant in linear time. - let (variant, _) = discriminants - .find(|&(_, discr)| discr.val == value) - .expect("Order of `AdtDef::discriminants` differed from `SwitchInt::values`"); + discr.place().and_then(|discr| { + switch_on_enum_discriminant(self.tcx, self.body, &self.body[block], discr).map( + |(enum_place, enum_def)| MaybePlacesSwitchIntData { + enum_place, + discriminants: enum_def.discriminants(self.tcx).collect(), + index: 0, + }, + ) + }) + } + fn apply_switch_int_edge_effect( + &mut self, + data: &mut Self::SwitchIntData, + state: &mut Self::Domain, + edge: SwitchIntTarget, + ) { + if let Some(value) = edge.value { // Kill all move paths that correspond to variants we know to be inactive along this // particular outgoing edge of a `SwitchInt`. drop_flag_effects::on_all_inactive_variants( - self.move_data(), - enum_place, - variant, + self.move_data, + data.enum_place, + data.next_discr(value), |mpi| state.kill(mpi), ); - }); + } } } @@ -378,6 +401,8 @@ pub type MaybeUninitializedPlacesDomain = MixedBitSet<MovePathIndex>; impl<'tcx> Analysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> { type Domain = MaybeUninitializedPlacesDomain; + type SwitchIntData = MaybePlacesSwitchIntData<'tcx>; + const NAME: &'static str = "maybe_uninit"; fn bottom_value(&self, _: &mir::Body<'tcx>) -> Self::Domain { @@ -447,50 +472,46 @@ impl<'tcx> Analysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> { }); } - fn apply_switch_int_edge_effects( + fn get_switch_int_data( &mut self, block: mir::BasicBlock, discr: &mir::Operand<'tcx>, - edge_effects: &mut impl SwitchIntEdgeEffects<Self::Domain>, - ) { + ) -> Option<Self::SwitchIntData> { if !self.tcx.sess.opts.unstable_opts.precise_enum_drop_elaboration { - return; + return None; } if !self.mark_inactive_variants_as_uninit { - return; + return None; } - let enum_ = discr.place().and_then(|discr| { - switch_on_enum_discriminant(self.tcx, self.body, &self.body[block], discr) - }); - - let Some((enum_place, enum_def)) = enum_ else { - return; - }; - - let mut discriminants = enum_def.discriminants(self.tcx); - edge_effects.apply(|state, edge| { - let Some(value) = edge.value else { - return; - }; - - // MIR building adds discriminants to the `values` array in the same order as they - // are yielded by `AdtDef::discriminants`. We rely on this to match each - // discriminant in `values` to its corresponding variant in linear time. - let (variant, _) = discriminants - .find(|&(_, discr)| discr.val == value) - .expect("Order of `AdtDef::discriminants` differed from `SwitchInt::values`"); + discr.place().and_then(|discr| { + switch_on_enum_discriminant(self.tcx, self.body, &self.body[block], discr).map( + |(enum_place, enum_def)| MaybePlacesSwitchIntData { + enum_place, + discriminants: enum_def.discriminants(self.tcx).collect(), + index: 0, + }, + ) + }) + } + fn apply_switch_int_edge_effect( + &mut self, + data: &mut Self::SwitchIntData, + state: &mut Self::Domain, + edge: SwitchIntTarget, + ) { + if let Some(value) = edge.value { // Mark all move paths that correspond to variants other than this one as maybe // uninitialized (in reality, they are *definitely* uninitialized). drop_flag_effects::on_all_inactive_variants( - self.move_data(), - enum_place, - variant, + self.move_data, + data.enum_place, + data.next_discr(value), |mpi| state.gen_(mpi), ); - }); + } } } |