|
2 | 2 |
|
3 | 3 | use crate::MirPass; |
4 | 4 | use rustc_data_structures::fx::FxHashSet; |
| 5 | +use rustc_middle::mir::patch::MirPatch; |
5 | 6 | use rustc_middle::mir::{ |
6 | | - BasicBlockData, Body, Local, Operand, Rvalue, StatementKind, Terminator, TerminatorKind, |
| 7 | + BasicBlockData, Body, Local, Operand, Rvalue, StatementKind, TerminatorKind, |
7 | 8 | }; |
8 | 9 | use rustc_middle::ty::layout::TyAndLayout; |
9 | 10 | use rustc_middle::ty::{Ty, TyCtxt}; |
@@ -77,8 +78,8 @@ impl<'tcx> MirPass<'tcx> for UninhabitedEnumBranching { |
77 | 78 | fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { |
78 | 79 | trace!("UninhabitedEnumBranching starting for {:?}", body.source); |
79 | 80 |
|
80 | | - let mut removable_switchs = Vec::new(); |
81 | | - let mut otherwise_is_last_variant_switchs = Vec::new(); |
| 81 | + let mut unreachable_targets = Vec::new(); |
| 82 | + let mut patch = MirPatch::new(body); |
82 | 83 |
|
83 | 84 | for (bb, bb_data) in body.basic_blocks.iter_enumerated() { |
84 | 85 | trace!("processing block {:?}", bb); |
@@ -107,49 +108,41 @@ impl<'tcx> MirPass<'tcx> for UninhabitedEnumBranching { |
107 | 108 |
|
108 | 109 | trace!("allowed_variants = {:?}", allowed_variants); |
109 | 110 |
|
110 | | - let terminator = bb_data.terminator(); |
111 | | - let TerminatorKind::SwitchInt { targets, .. } = &terminator.kind else { bug!() }; |
| 111 | + unreachable_targets.clear(); |
| 112 | + let TerminatorKind::SwitchInt { targets, discr } = &bb_data.terminator().kind else { |
| 113 | + bug!() |
| 114 | + }; |
112 | 115 |
|
113 | 116 | for (index, (val, _)) in targets.iter().enumerate() { |
114 | 117 | if !allowed_variants.remove(&val) { |
115 | | - removable_switchs.push((bb, index)); |
| 118 | + unreachable_targets.push(index); |
116 | 119 | } |
117 | 120 | } |
118 | 121 |
|
119 | | - if allowed_variants.is_empty() { |
120 | | - removable_switchs.push((bb, targets.iter().count())); |
121 | | - } else if allowed_variants.len() == 1 |
122 | | - && !body.basic_blocks[targets.otherwise()].is_empty_unreachable() |
123 | | - { |
124 | | - #[allow(rustc::potential_query_instability)] |
125 | | - let last_variant = *allowed_variants.iter().next().unwrap(); |
126 | | - otherwise_is_last_variant_switchs.push((bb, last_variant)); |
127 | | - } |
128 | | - } |
| 122 | + let replace_otherwise_to_unreachable = allowed_variants.len() <= 1 |
| 123 | + && !body.basic_blocks[targets.otherwise()].is_empty_unreachable(); |
129 | 124 |
|
130 | | - for (bb, last_variant) in otherwise_is_last_variant_switchs { |
131 | | - let bb_data = &mut body.basic_blocks.as_mut()[bb]; |
132 | | - let terminator = bb_data.terminator_mut(); |
133 | | - let TerminatorKind::SwitchInt { targets, .. } = &mut terminator.kind else { bug!() }; |
134 | | - targets.add_target(last_variant, targets.otherwise()); |
135 | | - removable_switchs.push((bb, targets.iter().count())); |
136 | | - } |
| 125 | + if unreachable_targets.is_empty() && !replace_otherwise_to_unreachable { |
| 126 | + continue; |
| 127 | + } |
137 | 128 |
|
138 | | - if removable_switchs.is_empty() { |
139 | | - return; |
| 129 | + let unreachable_block = patch.unreachable_no_cleanup_block(); |
| 130 | + let mut targets = targets.clone(); |
| 131 | + if replace_otherwise_to_unreachable { |
| 132 | + let otherwise_is_last_variant = !allowed_variants.is_empty(); |
| 133 | + if otherwise_is_last_variant { |
| 134 | + #[allow(rustc::potential_query_instability)] |
| 135 | + let last_variant = *allowed_variants.iter().next().unwrap(); |
| 136 | + targets.add_target(last_variant, targets.otherwise()); |
| 137 | + } |
| 138 | + unreachable_targets.push(targets.iter().count()); |
| 139 | + } |
| 140 | + for index in unreachable_targets.iter() { |
| 141 | + targets.all_targets_mut()[*index] = unreachable_block; |
| 142 | + } |
| 143 | + patch.patch_terminator(bb, TerminatorKind::SwitchInt { targets, discr: discr.clone() }); |
140 | 144 | } |
141 | 145 |
|
142 | | - let new_block = BasicBlockData::new(Some(Terminator { |
143 | | - source_info: body.basic_blocks[removable_switchs[0].0].terminator().source_info, |
144 | | - kind: TerminatorKind::Unreachable, |
145 | | - })); |
146 | | - let unreachable_block = body.basic_blocks.as_mut().push(new_block); |
147 | | - |
148 | | - for (bb, index) in removable_switchs { |
149 | | - let bb = &mut body.basic_blocks.as_mut()[bb]; |
150 | | - let terminator = bb.terminator_mut(); |
151 | | - let TerminatorKind::SwitchInt { targets, .. } = &mut terminator.kind else { bug!() }; |
152 | | - targets.all_targets_mut()[index] = unreachable_block; |
153 | | - } |
| 146 | + patch.apply(body); |
154 | 147 | } |
155 | 148 | } |
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