bjoernager/rust
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Add pass to identify undefined or erroneous behaviour

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This commit is contained in:
Tomasz Miąsko 2023-12-12 00:00:00 +00:00
parent 920e0051cf
commit 7a246ddd8e
7 changed files with 95 additions and 49 deletions
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50
compiler/rustc_const_eval/src/transform/validate.rs
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@ -8,9 +8,6 @@ use rustc_middle::mir::interpret::Scalar;
use rustc_middle::mir::visit::{NonUseContext, PlaceContext, Visitor};
use rustc_middle::mir::*;
use rustc_middle::ty::{self, InstanceDef, ParamEnv, Ty, TyCtxt, TypeVisitableExt, Variance};
use rustc_mir_dataflow::impls::MaybeStorageLive;
use rustc_mir_dataflow::storage::always_storage_live_locals;
use rustc_mir_dataflow::{Analysis, ResultsCursor};
use rustc_target::abi::{Size, FIRST_VARIANT};
use rustc_target::spec::abi::Abi;
@ -51,12 +48,6 @@ impl<'tcx> MirPass<'tcx> for Validator {
Reveal::All => tcx.param_env_reveal_all_normalized(def_id),
};
let always_live_locals = always_storage_live_locals(body);
let storage_liveness = MaybeStorageLive::new(std::borrow::Cow::Owned(always_live_locals))
.into_engine(tcx, body)
.iterate_to_fixpoint()
.into_results_cursor(body);
let can_unwind = if mir_phase <= MirPhase::Runtime(RuntimePhase::Initial) {
// In this case `AbortUnwindingCalls` haven't yet been executed.
true
@ -83,7 +74,6 @@ impl<'tcx> MirPass<'tcx> for Validator {
mir_phase,
unwind_edge_count: 0,
reachable_blocks: traversal::reachable_as_bitset(body),
storage_liveness,
place_cache: FxHashSet::default(),
value_cache: FxHashSet::default(),
can_unwind,
@ -116,7 +106,6 @@ struct CfgChecker<'a, 'tcx> {
mir_phase: MirPhase,
unwind_edge_count: usize,
reachable_blocks: BitSet<BasicBlock>,
storage_liveness: ResultsCursor<'a, 'tcx, MaybeStorageLive<'static>>,
place_cache: FxHashSet<PlaceRef<'tcx>>,
value_cache: FxHashSet<u128>,
// If `false`, then the MIR must not contain `UnwindAction::Continue` or
@ -294,28 +283,13 @@ impl<'a, 'tcx> CfgChecker<'a, 'tcx> {
}
impl<'a, 'tcx> Visitor<'tcx> for CfgChecker<'a, 'tcx> {
fn visit_local(&mut self, local: Local, context: PlaceContext, location: Location) {
fn visit_local(&mut self, local: Local, _context: PlaceContext, location: Location) {
if self.body.local_decls.get(local).is_none() {
self.fail(
location,
format!("local {local:?} has no corresponding declaration in `body.local_decls`"),
);
}
if self.reachable_blocks.contains(location.block) && context.is_use() {
// We check that the local is live whenever it is used. Technically, violating this
// restriction is only UB and not actually indicative of not well-formed MIR. This means
// that an optimization which turns MIR that already has UB into MIR that fails this
// check is not necessarily wrong. However, we have no such optimizations at the moment,
// and so we include this check anyway to help us catch bugs. If you happen to write an
// optimization that might cause this to incorrectly fire, feel free to remove this
// check.
self.storage_liveness.seek_after_primary_effect(location);
let locals_with_storage = self.storage_liveness.get();
if !locals_with_storage.contains(local) {
self.fail(location, format!("use of local {local:?}, which has no storage here"));
}
}
}
fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) {
@ -367,26 +341,8 @@ impl<'a, 'tcx> Visitor<'tcx> for CfgChecker<'a, 'tcx> {
self.fail(location, format!("explicit `{kind:?}` is forbidden"));
}
}
StatementKind::StorageLive(local) => {
// We check that the local is not live when entering a `StorageLive` for it.
// Technically, violating this restriction is only UB and not actually indicative
// of not well-formed MIR. This means that an optimization which turns MIR that
// already has UB into MIR that fails this check is not necessarily wrong. However,
// we have no such optimizations at the moment, and so we include this check anyway
// to help us catch bugs. If you happen to write an optimization that might cause
// this to incorrectly fire, feel free to remove this check.
if self.reachable_blocks.contains(location.block) {
self.storage_liveness.seek_before_primary_effect(location);
let locals_with_storage = self.storage_liveness.get();
if locals_with_storage.contains(*local) {
self.fail(
location,
format!("StorageLive({local:?}) which already has storage here"),
);
}
}
}
StatementKind::StorageDead(_)
StatementKind::StorageLive(_)
| StatementKind::StorageDead(_)
| StatementKind::Intrinsic(_)
| StatementKind::Coverage(_)
| StatementKind::ConstEvalCounter