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Tell the user about stacked borrow debugging flags

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This commit is contained in:
Oliver Scherer 2019-12-24 02:16:43 +01:00
parent 96d6efdf32
commit bb58e42da2
1 changed files with 31 additions and 13 deletions
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44
src/stacked_borrows.rs
View file

@ -4,6 +4,7 @@
use std::cell::RefCell;
use std::collections::{HashMap, HashSet};
use std::fmt;
use std::fmt::Write;
use std::num::NonZeroU64;
use std::rc::Rc;
@ -278,10 +279,13 @@ impl<'tcx> Stack {
if let Some(call) = item.protector {
if global.is_active(call) {
if let Some(tag) = tag {
throw_ub!(UbExperimental(format!(
"not granting access to tag {:?} because incompatible item is protected: {:?}",
tag, item
)));
return Err(err_ub_experimental(
tag,
format!(
"not granting access to tag {:?} because incompatible item is protected: {:?}",
tag, item
),
));
} else {
throw_ub!(UbExperimental(format!(
"deallocating while item is protected: {:?}",
@ -300,10 +304,10 @@ impl<'tcx> Stack {
// Step 1: Find granting item.
let granting_idx = self.find_granting(access, tag).ok_or_else(|| {
err_ub!(UbExperimental(format!(
"no item granting {} to tag {:?} found in borrow stack",
access, tag,
)))
err_ub_experimental(
tag,
format!("no item granting {} to tag {:?} found in borrow stack.", access, tag),
)
})?;
// Step 2: Remove incompatible items above them. Make sure we do not remove protected
@ -344,10 +348,11 @@ impl<'tcx> Stack {
fn dealloc(&mut self, tag: Tag, global: &GlobalState) -> InterpResult<'tcx> {
// Step 1: Find granting item.
self.find_granting(AccessKind::Write, tag).ok_or_else(|| {
err_ub!(UbExperimental(format!(
err_ub_experimental(
tag,format!(
"no item granting write access for deallocation to tag {:?} found in borrow stack",
tag,
)))
))
})?;
// Step 2: Remove all items. Also checks for protectors.
@ -369,9 +374,14 @@ impl<'tcx> Stack {
// Now we figure out which item grants our parent (`derived_from`) this kind of access.
// We use that to determine where to put the new item.
let granting_idx = self.find_granting(access, derived_from)
.ok_or_else(|| err_ub!(UbExperimental(format!(
"trying to reborrow for {:?}, but parent tag {:?} does not have an appropriate item in the borrow stack", new.perm, derived_from,
))))?;
.ok_or_else(||
err_ub_experimental(
derived_from,
format!(
"trying to reborrow for {:?}, but parent tag {:?} does not have an appropriate item in the borrow stack",
new.perm, derived_from,
),
))?;
// Compute where to put the new item.
// Either way, we ensure that we insert the new item in a way such that between
@ -638,3 +648,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
Ok(())
}
}
fn err_ub_experimental(tag: Tag, mut msg: String) -> InterpErrorInfo<'static> {
if let Tag::Tagged(id) = tag {
// FIXME: do not add this message when the flag is already set
write!(msg, " Rerun with `-Zmiri-track-pointer-tag={}` for more information", id).unwrap();
}
err_ub!(UbExperimental(msg)).into()
}