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Rollup merge of #73133 - doctorn:unwind-mir-validation, r=jonas-schievink

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Enforce unwind invariants

I had a quick look at #72959. The failure message probably needs to be more detailed but I just wanted to check I got the right idea. I have no idea how to right a test for this either...

r? @jonas-schievink

Resolves #72959 (hypothetically)
This commit is contained in:
Dylan DPC 2020-06-10 01:06:30 +02:00 • committed by GitHub
commit 161a8bf865
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1 changed files with 48 additions and 19 deletions
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67
src/librustc_mir/transform/validate.rs
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@ -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.