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librustc: De-@mut the undo log in RegionVarBindings

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This commit is contained in:
Patrick Walton 2013-12-20 13:29:48 -08:00
parent b84f294c46
commit 38d5072018
1 changed files with 57 additions and 32 deletions
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89
src/librustc/middle/typeck/infer/region_inference/mod.rs
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@ -103,7 +103,7 @@ pub struct RegionVarBindings {
// actively snapshotting. The reason for this is that otherwise
// we end up adding entries for things like the lower bound on
// a variable and so forth, which can never be rolled back.
undo_log: ~[UndoLogEntry],
undo_log: RefCell<~[UndoLogEntry]>,
// This contains the results of inference. It begins as an empty
// option and only acquires a value after inference is complete.
@ -120,36 +120,45 @@ pub fn RegionVarBindings(tcx: ty::ctxt) -> RegionVarBindings {
glbs: RefCell::new(HashMap::new()),
skolemization_count: Cell::new(0),
bound_count: Cell::new(0),
undo_log: ~[]
undo_log: RefCell::new(~[])
}
}
impl RegionVarBindings {
pub fn in_snapshot(&self) -> bool {
self.undo_log.len() > 0
let undo_log = self.undo_log.borrow();
undo_log.get().len() > 0
}
pub fn start_snapshot(&mut self) -> uint {
debug!("RegionVarBindings: snapshot()={}", self.undo_log.len());
debug!("RegionVarBindings: start_snapshot()");
if self.in_snapshot() {
self.undo_log.len()
{
let undo_log = self.undo_log.borrow();
undo_log.get().len()
}
} else {
self.undo_log.push(Snapshot);
0
{
let mut undo_log = self.undo_log.borrow_mut();
undo_log.get().push(Snapshot);
0
}
}
}
pub fn commit(&mut self) {
debug!("RegionVarBindings: commit()");
while self.undo_log.len() > 0 {
self.undo_log.pop();
let mut undo_log = self.undo_log.borrow_mut();
while undo_log.get().len() > 0 {
undo_log.get().pop();
}
}
pub fn rollback_to(&mut self, snapshot: uint) {
debug!("RegionVarBindings: rollback_to({})", snapshot);
while self.undo_log.len() > snapshot {
let undo_item = self.undo_log.pop();
let mut undo_log = self.undo_log.borrow_mut();
while undo_log.get().len() > snapshot {
let undo_item = undo_log.get().pop();
debug!("undo_item={:?}", undo_item);
match undo_item {
Snapshot => {}
@ -182,7 +191,10 @@ impl RegionVarBindings {
self.var_origins.push(origin);
let vid = RegionVid { id: id };
if self.in_snapshot() {
self.undo_log.push(AddVar(vid));
{
let mut undo_log = self.undo_log.borrow_mut();
undo_log.get().push(AddVar(vid));
}
}
debug!("created new region variable {:?} with origin {:?}",
vid, origin.repr(self.tcx));
@ -235,7 +247,10 @@ impl RegionVarBindings {
let mut constraints = self.constraints.borrow_mut();
if constraints.get().insert(constraint, origin) {
if self.in_snapshot() {
self.undo_log.push(AddConstraint(constraint));
{
let mut undo_log = self.undo_log.borrow_mut();
undo_log.get().push(AddConstraint(constraint));
}
}
}
}
@ -380,7 +395,10 @@ impl RegionVarBindings {
map.get().insert(vars, c);
}
if self.in_snapshot() {
self.undo_log.push(AddCombination(t, vars));
{
let mut undo_log = self.undo_log.borrow_mut();
undo_log.get().push(AddCombination(t, vars));
}
}
relate(self, a, ReInfer(ReVar(c)));
relate(self, b, ReInfer(ReVar(c)));
@ -390,7 +408,8 @@ impl RegionVarBindings {
pub fn vars_created_since_snapshot(&mut self, snapshot: uint)
-> ~[RegionVid] {
self.undo_log.slice_from(snapshot).iter()
let undo_log = self.undo_log.borrow();
undo_log.get().slice_from(snapshot).iter()
.filter_map(|&elt| match elt {
AddVar(vid) => Some(vid),
_ => None
@ -410,7 +429,10 @@ impl RegionVarBindings {
debug!("tainted(snapshot={}, r0={:?})", snapshot, r0);
let _indenter = indenter();
let undo_len = self.undo_log.len();
let undo_len = {
let undo_log = self.undo_log.borrow();
undo_log.get().len()
};
// `result_set` acts as a worklist: we explore all outgoing
// edges and add any new regions we find to result_set. This
@ -426,22 +448,25 @@ impl RegionVarBindings {
let mut undo_index = snapshot;
while undo_index < undo_len {
// nb: can't use uint::range() here as we move result_set
let regs = match self.undo_log[undo_index] {
AddConstraint(ConstrainVarSubVar(ref a, ref b)) => {
Some((ReInfer(ReVar(*a)),
ReInfer(ReVar(*b))))
}
AddConstraint(ConstrainRegSubVar(ref a, ref b)) => {
Some((*a, ReInfer(ReVar(*b))))
}
AddConstraint(ConstrainVarSubReg(ref a, ref b)) => {
Some((ReInfer(ReVar(*a)), *b))
}
AddConstraint(ConstrainRegSubReg(a, b)) => {
Some((a, b))
}
_ => {
None
let regs = {
let undo_log = self.undo_log.borrow();
match undo_log.get()[undo_index] {
AddConstraint(ConstrainVarSubVar(ref a, ref b)) => {
Some((ReInfer(ReVar(*a)),
ReInfer(ReVar(*b))))
}
AddConstraint(ConstrainRegSubVar(ref a, ref b)) => {
Some((*a, ReInfer(ReVar(*b))))
}
AddConstraint(ConstrainVarSubReg(ref a, ref b)) => {
Some((ReInfer(ReVar(*a)), *b))
}
AddConstraint(ConstrainRegSubReg(a, b)) => {
Some((a, b))
}
_ => {
None
}
}
};