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|
pub use super::*;
use rustc::mir::*;
use crate::dataflow::BitDenotation;
#[derive(Copy, Clone)]
pub struct MaybeStorageLive<'a, 'tcx: 'a> {
mir: &'a Mir<'tcx>,
}
impl<'a, 'tcx: 'a> MaybeStorageLive<'a, 'tcx> {
pub fn new(mir: &'a Mir<'tcx>)
-> Self {
MaybeStorageLive { mir }
}
pub fn mir(&self) -> &Mir<'tcx> {
self.mir
}
}
impl<'a, 'tcx> BitDenotation<'tcx> for MaybeStorageLive<'a, 'tcx> {
type Idx = Local;
fn name() -> &'static str { "maybe_storage_live" }
fn bits_per_block(&self) -> usize {
self.mir.local_decls.len()
}
fn start_block_effect(&self, _sets: &mut BitSet<Local>) {
// Nothing is live on function entry
}
fn statement_effect(&self,
sets: &mut BlockSets<'_, Local>,
loc: Location) {
let stmt = &self.mir[loc.block].statements[loc.statement_index];
match stmt.kind {
StatementKind::StorageLive(l) => sets.gen(l),
StatementKind::StorageDead(l) => sets.kill(l),
_ => (),
}
}
fn terminator_effect(&self,
_sets: &mut BlockSets<'_, Local>,
_loc: Location) {
// Terminators have no effect
}
fn propagate_call_return(
&self,
_in_out: &mut BitSet<Local>,
_call_bb: mir::BasicBlock,
_dest_bb: mir::BasicBlock,
_dest_place: &mir::Place<'tcx>,
) {
// Nothing to do when a call returns successfully
}
}
impl<'a, 'tcx> BitSetOperator for MaybeStorageLive<'a, 'tcx> {
#[inline]
fn join<T: Idx>(&self, inout_set: &mut BitSet<T>, in_set: &BitSet<T>) -> bool {
inout_set.union(in_set) // "maybe" means we union effects of both preds
}
}
impl<'a, 'tcx> InitialFlow for MaybeStorageLive<'a, 'tcx> {
#[inline]
fn bottom_value() -> bool {
false // bottom = dead
}
}
|
