squiid/rust
1
0
Fork 0
Code Issues Pull requests Projects Activity

Avoid trivial checks on cleanup control flow in MIR validator

Browse source
This commit is contained in:
Jakob Degen 2023-01-16 15:01:16 -08:00
parent ec3d993410
commit 4bc963eba6
1 changed files with 11 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

15
compiler/rustc_const_eval/src/transform/validate.rs
View file

@ -64,6 +64,7 @@ impl<'tcx> MirPass<'tcx> for Validator {
tcx,
param_env,
mir_phase,
unwind_edge_count: 0,
reachable_blocks: traversal::reachable_as_bitset(body),
storage_liveness,
place_cache: Vec::new(),
@ -80,6 +81,7 @@ struct TypeChecker<'a, 'tcx> {
tcx: TyCtxt<'tcx>,
param_env: ParamEnv<'tcx>,
mir_phase: MirPhase,
unwind_edge_count: usize,
reachable_blocks: BitSet<BasicBlock>,
storage_liveness: ResultsCursor<'a, 'tcx, MaybeStorageLive<'static>>,
place_cache: Vec<PlaceRef<'tcx>>,
@ -104,7 +106,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
);
}
fn check_edge(&self, location: Location, bb: BasicBlock, edge_kind: EdgeKind) {
fn check_edge(&mut self, location: Location, bb: BasicBlock, edge_kind: EdgeKind) {
if bb == START_BLOCK {
self.fail(location, "start block must not have predecessors")
}
@ -113,10 +115,12 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
match (src.is_cleanup, bb.is_cleanup, edge_kind) {
// Non-cleanup blocks can jump to non-cleanup blocks along non-unwind edges
(false, false, EdgeKind::Normal)
// Non-cleanup blocks can jump to cleanup blocks along unwind edges
| (false, true, EdgeKind::Unwind)
// Cleanup blocks can jump to cleanup blocks along non-unwind edges
| (true, true, EdgeKind::Normal) => {}
// Non-cleanup blocks can jump to cleanup blocks along unwind edges
(false, true, EdgeKind::Unwind) => {
self.unwind_edge_count += 1;
}
// All other jumps are invalid
_ => {
self.fail(
@ -137,6 +141,9 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
}
fn check_cleanup_control_flow(&self) {
if self.unwind_edge_count <= 1 {
return;
}
let doms = self.body.basic_blocks.dominators();
let mut post_contract_node = FxHashMap::default();
// Reusing the allocation across invocations of the closure
@ -196,7 +203,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
stack.clear();
stack.insert(bb);
loop {
let Some(parent )= parent[bb].take() else {
let Some(parent)= parent[bb].take() else {
break
};
let no_cycle = stack.insert(parent);