diff --git a/src/librustc_mir/transform/validate.rs b/src/librustc_mir/transform/validate.rs index 1433d39abfbba..8150c328316cb 100644 --- a/src/librustc_mir/transform/validate.rs +++ b/src/librustc_mir/transform/validate.rs @@ -11,6 +11,12 @@ use rustc_middle::{ }; use rustc_span::def_id::DefId; +#[derive(Copy, Clone, Debug)] +enum EdgeKind { + Unwind, + Normal, +} + pub struct Validator { /// Describes at which point in the pipeline this validation is happening. pub when: String, @@ -49,8 +55,31 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> { ); } - fn check_bb(&self, location: Location, bb: BasicBlock) { - if self.body.basic_blocks().get(bb).is_none() { + fn check_edge(&self, location: Location, bb: BasicBlock, edge_kind: EdgeKind) { + if let Some(bb) = self.body.basic_blocks().get(bb) { + let src = self.body.basic_blocks().get(location.block).unwrap(); + 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) => {} + // All other jumps are invalid + _ => { + self.fail( + location, + format!( + "{:?} edge to {:?} violates unwind invariants (cleanup {:?} -> {:?})", + edge_kind, + bb, + src.is_cleanup, + bb.is_cleanup, + ) + ) + } + } + } else { self.fail(location, format!("encountered jump to invalid basic block {:?}", bb)) } } @@ -92,7 +121,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> { fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) { match &terminator.kind { TerminatorKind::Goto { target } => { - self.check_bb(location, *target); + self.check_edge(location, *target, EdgeKind::Normal); } TerminatorKind::SwitchInt { targets, values, .. } => { if targets.len() != values.len() + 1 { @@ -106,19 +135,19 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> { ); } for target in targets { - self.check_bb(location, *target); + self.check_edge(location, *target, EdgeKind::Normal); } } TerminatorKind::Drop { target, unwind, .. } => { - self.check_bb(location, *target); + self.check_edge(location, *target, EdgeKind::Normal); if let Some(unwind) = unwind { - self.check_bb(location, *unwind); + self.check_edge(location, *unwind, EdgeKind::Unwind); } } TerminatorKind::DropAndReplace { target, unwind, .. } => { - self.check_bb(location, *target); + self.check_edge(location, *target, EdgeKind::Normal); if let Some(unwind) = unwind { - self.check_bb(location, *unwind); + self.check_edge(location, *unwind, EdgeKind::Unwind); } } TerminatorKind::Call { func, destination, cleanup, .. } => { @@ -131,10 +160,10 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> { ), } if let Some((_, target)) = destination { - self.check_bb(location, *target); + self.check_edge(location, *target, EdgeKind::Normal); } if let Some(cleanup) = cleanup { - self.check_bb(location, *cleanup); + self.check_edge(location, *cleanup, EdgeKind::Unwind); } } TerminatorKind::Assert { cond, target, cleanup, .. } => { @@ -148,30 +177,30 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> { ), ); } - self.check_bb(location, *target); + self.check_edge(location, *target, EdgeKind::Normal); if let Some(cleanup) = cleanup { - self.check_bb(location, *cleanup); + self.check_edge(location, *cleanup, EdgeKind::Unwind); } } TerminatorKind::Yield { resume, drop, .. } => { - self.check_bb(location, *resume); + self.check_edge(location, *resume, EdgeKind::Normal); if let Some(drop) = drop { - self.check_bb(location, *drop); + self.check_edge(location, *drop, EdgeKind::Normal); } } TerminatorKind::FalseEdge { real_target, imaginary_target } => { - self.check_bb(location, *real_target); - self.check_bb(location, *imaginary_target); + self.check_edge(location, *real_target, EdgeKind::Normal); + self.check_edge(location, *imaginary_target, EdgeKind::Normal); } TerminatorKind::FalseUnwind { real_target, unwind } => { - self.check_bb(location, *real_target); + self.check_edge(location, *real_target, EdgeKind::Normal); if let Some(unwind) = unwind { - self.check_bb(location, *unwind); + self.check_edge(location, *unwind, EdgeKind::Unwind); } } TerminatorKind::InlineAsm { destination, .. } => { if let Some(destination) = destination { - self.check_bb(location, *destination); + self.check_edge(location, *destination, EdgeKind::Normal); } } // Nothing to validate for these.