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qualify_consts: extract remove_drop_and_storage_dead_on_promoted_locals.

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This commit is contained in:
Mazdak Farrokhzad 2019-08-29 09:43:16 +02:00
parent 8af33b3253
commit 2f733aad5a
1 changed files with 34 additions and 29 deletions
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63
src/librustc_mir/transform/qualify_consts.rs
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@ -1656,35 +1656,7 @@ impl<'tcx> MirPass<'tcx> for QualifyAndPromoteConstants<'tcx> {
Mode::Const => tcx.mir_const_qualif(def_id).1,
_ => Checker::new(tcx, def_id, body, mode).check_const().1,
};
// In `const` and `static` everything without `StorageDead`
// is `'static`, we don't have to create promoted MIR fragments,
// just remove `Drop` and `StorageDead` on "promoted" locals.
debug!("run_pass: promoted_temps={:?}", promoted_temps);
for block in body.basic_blocks_mut() {
block.statements.retain(|statement| {
match statement.kind {
StatementKind::StorageDead(index) => {
!promoted_temps.contains(index)
}
_ => true
}
});
let terminator = block.terminator_mut();
match terminator.kind {
TerminatorKind::Drop {
location: Place {
base: PlaceBase::Local(index),
projection: None,
},
target,
..
} if promoted_temps.contains(index) => {
terminator.kind = TerminatorKind::Goto { target };
}
_ => {}
}
}
remove_drop_and_storage_dead_on_promoted_locals(body, promoted_temps);
}
if let Mode::Static = mode {
@ -1738,6 +1710,39 @@ fn check_short_circuiting_in_const_local(tcx: TyCtxt<'_>, body: &mut Body<'tcx>,
}
}
/// In `const` and `static` everything without `StorageDead`
/// is `'static`, we don't have to create promoted MIR fragments,
/// just remove `Drop` and `StorageDead` on "promoted" locals.
fn remove_drop_and_storage_dead_on_promoted_locals(
body: &mut Body<'tcx>,
promoted_temps: &BitSet<Local>,
) {
debug!("run_pass: promoted_temps={:?}", promoted_temps);
for block in body.basic_blocks_mut() {
block.statements.retain(|statement| {
match statement.kind {
StatementKind::StorageDead(index) => !promoted_temps.contains(index),
_ => true
}
});
let terminator = block.terminator_mut();
match terminator.kind {
TerminatorKind::Drop {
location: Place {
base: PlaceBase::Local(index),
projection: None,
},
target,
..
} if promoted_temps.contains(index) => {
terminator.kind = TerminatorKind::Goto { target };
}
_ => {}
}
}
}
fn check_non_thread_local_static_is_sync(
tcx: TyCtxt<'tcx>,
body: &mut Body<'tcx>,