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Use visit_local to find 2PB activations

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This commit is contained in:
Matthew Jasper 2018-11-30 21:49:43 +00:00
parent 4f5b8eace1
commit 6000c2e0e1
1 changed files with 55 additions and 55 deletions
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110
src/librustc_mir/borrow_check/borrow_set.rs
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@ -230,68 +230,68 @@ impl<'a, 'gcx, 'tcx> Visitor<'tcx> for GatherBorrows<'a, 'gcx, 'tcx> {
self.super_assign(block, assigned_place, rvalue, location)
}
fn visit_place(
fn visit_local(
&mut self,
place: &mir::Place<'tcx>,
temp: &Local,
context: PlaceContext<'tcx>,
location: Location,
) {
self.super_place(place, context, location);
if !context.is_use() {
return;
}
// We found a use of some temporary TEMP...
if let Place::Local(temp) = place {
// ... check whether we (earlier) saw a 2-phase borrow like
//
// TMP = &mut place
if let Some(&borrow_index) = self.pending_activations.get(temp) {
let borrow_data = &mut self.idx_vec[borrow_index];
// We found a use of some temporary TMP
// check whether we (earlier) saw a 2-phase borrow like
//
// TMP = &mut place
if let Some(&borrow_index) = self.pending_activations.get(temp) {
let borrow_data = &mut self.idx_vec[borrow_index];
// Watch out: the use of TMP in the borrow itself
// doesn't count as an activation. =)
if borrow_data.reserve_location == location &&
context == PlaceContext::MutatingUse(MutatingUseContext::Store)
{
return;
}
if let TwoPhaseActivation::ActivatedAt(other_location) =
borrow_data.activation_location {
span_bug!(
self.mir.source_info(location).span,
"found two uses for 2-phase borrow temporary {:?}: \
{:?} and {:?}",
temp,
location,
other_location,
);
}
// Otherwise, this is the unique later use
// that we expect.
borrow_data.activation_location = match context {
// The use of TMP in a shared borrow does not
// count as an actual activation.
PlaceContext::NonMutatingUse(NonMutatingUseContext::SharedBorrow(..)) |
PlaceContext::NonMutatingUse(NonMutatingUseContext::ShallowBorrow(..)) =>
TwoPhaseActivation::NotActivated,
_ => {
// Double check: This borrow is indeed a two-phase borrow (that is,
// we are 'transitioning' from `NotActivated` to `ActivatedAt`) and
// we've not found any other activations (checked above).
assert_eq!(
borrow_data.activation_location,
TwoPhaseActivation::NotActivated,
"never found an activation for this borrow!",
);
self.activation_map
.entry(location)
.or_default()
.push(borrow_index);
TwoPhaseActivation::ActivatedAt(location)
}
};
// Watch out: the use of TMP in the borrow itself
// doesn't count as an activation. =)
if borrow_data.reserve_location == location &&
context == PlaceContext::MutatingUse(MutatingUseContext::Store)
{
return;
}
if let TwoPhaseActivation::ActivatedAt(other_location) =
borrow_data.activation_location {
span_bug!(
self.mir.source_info(location).span,
"found two uses for 2-phase borrow temporary {:?}: \
{:?} and {:?}",
temp,
location,
other_location,
);
}
// Otherwise, this is the unique later use
// that we expect.
borrow_data.activation_location = match context {
// The use of TMP in a shared borrow does not
// count as an actual activation.
PlaceContext::NonMutatingUse(NonMutatingUseContext::SharedBorrow(..)) |
PlaceContext::NonMutatingUse(NonMutatingUseContext::ShallowBorrow(..)) =>
TwoPhaseActivation::NotActivated,
_ => {
// Double check: This borrow is indeed a two-phase borrow (that is,
// we are 'transitioning' from `NotActivated` to `ActivatedAt`) and
// we've not found any other activations (checked above).
assert_eq!(
borrow_data.activation_location,
TwoPhaseActivation::NotActivated,
"never found an activation for this borrow!",
);
self.activation_map
.entry(location)
.or_default()
.push(borrow_index);
TwoPhaseActivation::ActivatedAt(location)
}
};
}
}