bjoernager/rust
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Refactor how SwitchInt stores jump targets

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This commit is contained in:
Jonas Schievink 2020-10-10 17:36:04 +02:00
parent cae8bc1f23
commit 432535da2b
22 changed files with 247 additions and 206 deletions
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60
compiler/rustc_mir_build/src/build/matches/test.rs
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@ -167,48 +167,42 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
let target_blocks = make_target_blocks(self);
// Variants is a BitVec of indexes into adt_def.variants.
let num_enum_variants = adt_def.variants.len();
let used_variants = variants.count();
debug_assert_eq!(target_blocks.len(), num_enum_variants + 1);
let otherwise_block = *target_blocks.last().unwrap();
let mut targets = Vec::with_capacity(used_variants + 1);
let mut values = Vec::with_capacity(used_variants);
let tcx = self.hir.tcx();
for (idx, discr) in adt_def.discriminants(tcx) {
if variants.contains(idx) {
debug_assert_ne!(
target_blocks[idx.index()],
otherwise_block,
"no canididates for tested discriminant: {:?}",
discr,
);
values.push(discr.val);
targets.push(target_blocks[idx.index()]);
} else {
debug_assert_eq!(
target_blocks[idx.index()],
otherwise_block,
"found canididates for untested discriminant: {:?}",
discr,
);
}
}
targets.push(otherwise_block);
debug!(
"num_enum_variants: {}, tested variants: {:?}, variants: {:?}",
num_enum_variants, values, variants
let switch_targets = SwitchTargets::new(
adt_def.discriminants(tcx).filter_map(|(idx, discr)| {
if variants.contains(idx) {
debug_assert_ne!(
target_blocks[idx.index()],
otherwise_block,
"no canididates for tested discriminant: {:?}",
discr,
);
Some((discr.val, target_blocks[idx.index()]))
} else {
debug_assert_eq!(
target_blocks[idx.index()],
otherwise_block,
"found canididates for untested discriminant: {:?}",
discr,
);
None
}
}),
otherwise_block,
);
debug!("num_enum_variants: {}, variants: {:?}", num_enum_variants, variants);
let discr_ty = adt_def.repr.discr_type().to_ty(tcx);
let discr = self.temp(discr_ty, test.span);
self.cfg.push_assign(block, source_info, discr, Rvalue::Discriminant(place));
assert_eq!(values.len() + 1, targets.len());
self.cfg.terminate(
block,
source_info,
TerminatorKind::SwitchInt {
discr: Operand::Move(discr),
switch_ty: discr_ty,
values: From::from(values),
targets,
targets: switch_targets,
},
);
}
@ -230,11 +224,15 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
} else {
// The switch may be inexhaustive so we have a catch all block
debug_assert_eq!(options.len() + 1, target_blocks.len());
let otherwise_block = *target_blocks.last().unwrap();
let switch_targets = SwitchTargets::new(
options.values().copied().zip(target_blocks),
otherwise_block,
);
TerminatorKind::SwitchInt {
discr: Operand::Copy(place),
switch_ty,
values: options.values().copied().collect(),
targets: target_blocks,
targets: switch_targets,
}
};
self.cfg.terminate(block, source_info, terminator);