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Enforce unwind invariants

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This commit is contained in:
Nathan Corbyn 2020-06-08 13:54:20 +01:00
parent 7355816093
commit 3aedfbecfd
1 changed files with 41 additions and 19 deletions
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60
src/librustc_mir/transform/validate.rs
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@ -11,6 +11,11 @@ use rustc_middle::{
}; };
use rustc_span::def_id::DefId; use rustc_span::def_id::DefId;
enum EdgeKind {
Unwind,
Other,
}
pub struct Validator { pub struct Validator {
/// Describes at which point in the pipeline this validation is happening. /// Describes at which point in the pipeline this validation is happening.
pub when: String, pub when: String,
@ -49,8 +54,25 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
); );
} }
fn check_bb(&self, location: Location, bb: BasicBlock) { fn check_bb(&self, location: Location, bb: BasicBlock, edge_kind: EdgeKind) {
if self.body.basic_blocks().get(bb).is_none() { 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::Other)
// Non-cleanup blocks can jump to cleanup blocks along unwind edges
| (false, true, EdgeKind::Unwind)
// Cleanup blocks can jump to cleanup blocks along unwind edges
| (true, true, EdgeKind::Unwind) => {}
// All other jumps are invalid
_ => {
self.fail(
location,
format!("encountered jump that does not respect unwind invariants {:?}", bb)
)
}
}
} else {
self.fail(location, format!("encountered jump to invalid basic block {:?}", bb)) self.fail(location, format!("encountered jump to invalid basic block {:?}", bb))
} }
} }
@ -92,7 +114,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) { fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
match &terminator.kind { match &terminator.kind {
TerminatorKind::Goto { target } => { TerminatorKind::Goto { target } => {
self.check_bb(location, *target); self.check_bb(location, *target, EdgeKind::Other);
} }
TerminatorKind::SwitchInt { targets, values, .. } => { TerminatorKind::SwitchInt { targets, values, .. } => {
if targets.len() != values.len() + 1 { if targets.len() != values.len() + 1 {
@ -106,19 +128,19 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
); );
} }
for target in targets { for target in targets {
self.check_bb(location, *target); self.check_bb(location, *target, EdgeKind::Other);
} }
} }
TerminatorKind::Drop { target, unwind, .. } => { TerminatorKind::Drop { target, unwind, .. } => {
self.check_bb(location, *target); self.check_bb(location, *target, EdgeKind::Other);
if let Some(unwind) = unwind { if let Some(unwind) = unwind {
self.check_bb(location, *unwind); self.check_bb(location, *unwind, EdgeKind::Unwind);
} }
} }
TerminatorKind::DropAndReplace { target, unwind, .. } => { TerminatorKind::DropAndReplace { target, unwind, .. } => {
self.check_bb(location, *target); self.check_bb(location, *target, EdgeKind::Other);
if let Some(unwind) = unwind { if let Some(unwind) = unwind {
self.check_bb(location, *unwind); self.check_bb(location, *unwind, EdgeKind::Unwind);
} }
} }
TerminatorKind::Call { func, destination, cleanup, .. } => { TerminatorKind::Call { func, destination, cleanup, .. } => {
@ -131,10 +153,10 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
), ),
} }
if let Some((_, target)) = destination { if let Some((_, target)) = destination {
self.check_bb(location, *target); self.check_bb(location, *target, EdgeKind::Other);
} }
if let Some(cleanup) = cleanup { if let Some(cleanup) = cleanup {
self.check_bb(location, *cleanup); self.check_bb(location, *cleanup, EdgeKind::Unwind);
} }
} }
TerminatorKind::Assert { cond, target, cleanup, .. } => { TerminatorKind::Assert { cond, target, cleanup, .. } => {
@ -148,30 +170,30 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
), ),
); );
} }
self.check_bb(location, *target); self.check_bb(location, *target, EdgeKind::Other);
if let Some(cleanup) = cleanup { if let Some(cleanup) = cleanup {
self.check_bb(location, *cleanup); self.check_bb(location, *cleanup, EdgeKind::Unwind);
} }
} }
TerminatorKind::Yield { resume, drop, .. } => { TerminatorKind::Yield { resume, drop, .. } => {
self.check_bb(location, *resume); self.check_bb(location, *resume, EdgeKind::Other);
if let Some(drop) = drop { if let Some(drop) = drop {
self.check_bb(location, *drop); self.check_bb(location, *drop, EdgeKind::Other);
} }
} }
TerminatorKind::FalseEdge { real_target, imaginary_target } => { TerminatorKind::FalseEdge { real_target, imaginary_target } => {
self.check_bb(location, *real_target); self.check_bb(location, *real_target, EdgeKind::Other);
self.check_bb(location, *imaginary_target); self.check_bb(location, *imaginary_target, EdgeKind::Other);
} }
TerminatorKind::FalseUnwind { real_target, unwind } => { TerminatorKind::FalseUnwind { real_target, unwind } => {
self.check_bb(location, *real_target); self.check_bb(location, *real_target, EdgeKind::Other);
if let Some(unwind) = unwind { if let Some(unwind) = unwind {
self.check_bb(location, *unwind); self.check_bb(location, *unwind, EdgeKind::Unwind);
} }
} }
TerminatorKind::InlineAsm { destination, .. } => { TerminatorKind::InlineAsm { destination, .. } => {
if let Some(destination) = destination { if let Some(destination) = destination {
self.check_bb(location, *destination); self.check_bb(location, *destination, EdgeKind::Other);
} }
} }
// Nothing to validate for these. // Nothing to validate for these.