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Check whether unwinding is allowed before popping the stack frame

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hyd-dev 2021-05-25 00:08:26 +08:00
parent ac39f36526
commit 64044eb237
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1 changed files with 15 additions and 16 deletions
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31
compiler/rustc_mir/src/interpret/eval_context.rs
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@ -798,26 +798,12 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
throw_ub_format!("unwinding past the topmost frame of the stack");
}
let frame =
self.stack_mut().pop().expect("tried to pop a stack frame, but there were none");
if !unwinding {
// Copy the return value to the caller's stack frame.
if let Some(ref return_place) = frame.return_place {
let op = self.access_local(&frame, mir::RETURN_PLACE, None)?;
self.copy_op_transmute(&op, return_place)?;
trace!("{:?}", self.dump_place(**return_place));
} else {
throw_ub!(Unreachable);
}
}
// Now where do we jump next?
// Where do we jump next?
// Usually we want to clean up (deallocate locals), but in a few rare cases we don't.
// In that case, we return early. We also avoid validation in that case,
// because this is CTFE and the final value will be thoroughly validated anyway.
let (cleanup, next_block) = match (frame.return_to_block, unwinding) {
let (cleanup, next_block) = match (self.frame().return_to_block, unwinding) {
(StackPopCleanup::Goto { ret, .. }, false) => (true, Some(ret)),
(StackPopCleanup::Goto { unwind, .. }, true) => (
true,
@ -832,6 +818,19 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
(StackPopCleanup::None { cleanup, .. }, _) => (cleanup, None),
};
let frame = self.stack_mut().pop().unwrap();
if !unwinding {
// Copy the return value to the caller's stack frame.
if let Some(ref return_place) = frame.return_place {
let op = self.access_local(&frame, mir::RETURN_PLACE, None)?;
self.copy_op_transmute(&op, return_place)?;
trace!("{:?}", self.dump_place(**return_place));
} else {
throw_ub!(Unreachable);
}
}
if !cleanup {
assert!(self.stack().is_empty(), "only the topmost frame should ever be leaked");
assert!(next_block.is_none(), "tried to skip cleanup when we have a next block!");