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use super::*;
#[derive(Debug)]
pub(super) struct TaintSet<'tcx> {
directions: TaintDirections,
regions: FxHashSet<ty::Region<'tcx>>
}
impl<'tcx> TaintSet<'tcx> {
pub(super) fn new(directions: TaintDirections,
initial_region: ty::Region<'tcx>)
-> Self {
let mut regions = FxHashSet();
regions.insert(initial_region);
TaintSet { directions: directions, regions: regions }
}
pub(super) fn fixed_point(&mut self,
tcx: TyCtxt<'_, '_, 'tcx>,
undo_log: &[UndoLogEntry<'tcx>],
verifys: &[Verify<'tcx>]) {
let mut prev_len = 0;
while prev_len < self.len() {
debug!("tainted: prev_len = {:?} new_len = {:?}",
prev_len, self.len());
prev_len = self.len();
for undo_entry in undo_log {
match undo_entry {
&AddConstraint(Constraint::VarSubVar(a, b)) => {
self.add_edge(tcx.mk_region(ReVar(a)),
tcx.mk_region(ReVar(b)));
}
&AddConstraint(Constraint::RegSubVar(a, b)) => {
self.add_edge(a, tcx.mk_region(ReVar(b)));
}
&AddConstraint(Constraint::VarSubReg(a, b)) => {
self.add_edge(tcx.mk_region(ReVar(a)), b);
}
&AddConstraint(Constraint::RegSubReg(a, b)) => {
self.add_edge(a, b);
}
&AddGiven(a, b) => {
self.add_edge(a, tcx.mk_region(ReVar(b)));
}
&AddVerify(i) => {
verifys[i].bound.for_each_region(&mut |b| {
self.add_edge(verifys[i].region, b);
});
}
&Purged |
&AddCombination(..) |
&AddVar(..) |
&OpenSnapshot |
&CommitedSnapshot => {}
}
}
}
}
pub(super) fn into_set(self) -> FxHashSet<ty::Region<'tcx>> {
self.regions
}
fn len(&self) -> usize {
self.regions.len()
}
fn add_edge(&mut self,
source: ty::Region<'tcx>,
target: ty::Region<'tcx>) {
if self.directions.incoming {
if self.regions.contains(&target) {
self.regions.insert(source);
}
}
if self.directions.outgoing {
if self.regions.contains(&source) {
self.regions.insert(target);
}
}
}
}