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slight simplifications for borrow tracking

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This commit is contained in:
Ralf Jung 2022-12-02 14:43:05 +01:00
parent 90118a197b
commit 595490e8dd
3 changed files with 36 additions and 58 deletions
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50
src/tools/miri/src/borrow_tracker/mod.rs
View file

@ -55,9 +55,9 @@ impl fmt::Debug for BorTag {
}
}
/// Per-frame data for borrow tracking
/// Per-call-stack-frame data for borrow tracking
#[derive(Debug)]
pub struct FrameExtra {
pub struct FrameState {
/// The ID of the call this frame corresponds to.
pub call_id: CallId,
@ -72,7 +72,7 @@ pub struct FrameExtra {
pub protected_tags: SmallVec<[BorTag; 2]>,
}
impl VisitTags for FrameExtra {
impl VisitTags for FrameState {
fn visit_tags(&self, _visit: &mut dyn FnMut(BorTag)) {
// `protected_tags` are fine to GC.
}
@ -190,14 +190,14 @@ impl GlobalStateInner {
id
}
pub fn new_frame(&mut self, machine: &MiriMachine<'_, '_>) -> FrameExtra {
pub fn new_frame(&mut self, machine: &MiriMachine<'_, '_>) -> FrameState {
let call_id = self.next_call_id;
trace!("new_frame: Assigning call ID {}", call_id);
if self.tracked_call_ids.contains(&call_id) {
machine.emit_diagnostic(NonHaltingDiagnostic::CreatedCallId(call_id));
}
self.next_call_id = NonZeroU64::new(call_id.get() + 1).unwrap();
FrameExtra { call_id, protected_tags: SmallVec::new() }
FrameState { call_id, protected_tags: SmallVec::new() }
}
pub fn end_call(&mut self, frame: &machine::FrameData<'_>) {
@ -253,10 +253,10 @@ impl GlobalStateInner {
alloc_size: Size,
kind: MemoryKind<machine::MiriMemoryKind>,
machine: &MiriMachine<'_, '_>,
) -> AllocExtra {
) -> AllocState {
match self.borrow_tracker_method {
BorrowTrackerMethod::StackedBorrows =>
AllocExtra::StackedBorrows(Box::new(RefCell::new(Stacks::new_allocation(
AllocState::StackedBorrows(Box::new(RefCell::new(Stacks::new_allocation(
id, alloc_size, self, kind, machine,
)))),
}
@ -292,24 +292,30 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
/// Extra per-allocation data for borrow tracking
#[derive(Debug, Clone)]
pub enum AllocExtra {
pub enum AllocState {
/// Data corresponding to Stacked Borrows
StackedBorrows(Box<RefCell<stacked_borrows::AllocExtra>>),
StackedBorrows(Box<RefCell<stacked_borrows::AllocState>>),
}
impl AllocExtra {
pub fn assert_sb(&self) -> &RefCell<stacked_borrows::AllocExtra> {
match self {
AllocExtra::StackedBorrows(ref sb) => sb,
impl machine::AllocExtra {
#[track_caller]
pub fn borrow_tracker_sb(&self) -> &RefCell<stacked_borrows::AllocState> {
match self.borrow_tracker {
Some(AllocState::StackedBorrows(ref sb)) => sb,
_ => panic!("expected Stacked Borrows borrow tracking, got something else"),
}
}
pub fn assert_sb_mut(&mut self) -> &mut RefCell<stacked_borrows::AllocExtra> {
match self {
AllocExtra::StackedBorrows(ref mut sb) => sb,
#[track_caller]
pub fn borrow_tracker_sb_mut(&mut self) -> &mut RefCell<stacked_borrows::AllocState> {
match self.borrow_tracker {
Some(AllocState::StackedBorrows(ref mut sb)) => sb,
_ => panic!("expected Stacked Borrows borrow tracking, got something else"),
}
}
}
impl AllocState {
pub fn before_memory_read<'tcx>(
&self,
alloc_id: AllocId,
@ -318,7 +324,7 @@ impl AllocExtra {
machine: &MiriMachine<'_, 'tcx>,
) -> InterpResult<'tcx> {
match self {
AllocExtra::StackedBorrows(sb) =>
AllocState::StackedBorrows(sb) =>
sb.borrow_mut().before_memory_read(alloc_id, prov_extra, range, machine),
}
}
@ -331,7 +337,7 @@ impl AllocExtra {
machine: &mut MiriMachine<'_, 'tcx>,
) -> InterpResult<'tcx> {
match self {
AllocExtra::StackedBorrows(sb) =>
AllocState::StackedBorrows(sb) =>
sb.get_mut().before_memory_write(alloc_id, prov_extra, range, machine),
}
}
@ -344,22 +350,22 @@ impl AllocExtra {
machine: &mut MiriMachine<'_, 'tcx>,
) -> InterpResult<'tcx> {
match self {
AllocExtra::StackedBorrows(sb) =>
AllocState::StackedBorrows(sb) =>
sb.get_mut().before_memory_deallocation(alloc_id, prov_extra, range, machine),
}
}
pub fn remove_unreachable_tags(&self, tags: &FxHashSet<BorTag>) {
match self {
AllocExtra::StackedBorrows(sb) => sb.borrow_mut().remove_unreachable_tags(tags),
AllocState::StackedBorrows(sb) => sb.borrow_mut().remove_unreachable_tags(tags),
}
}
}
impl VisitTags for AllocExtra {
impl VisitTags for AllocState {
fn visit_tags(&self, visit: &mut dyn FnMut(BorTag)) {
match self {
AllocExtra::StackedBorrows(sb) => sb.visit_tags(visit),
AllocState::StackedBorrows(sb) => sb.visit_tags(visit),
}
}
}

40
src/tools/miri/src/borrow_tracker/stacked_borrows/mod.rs
View file

@ -25,7 +25,7 @@ mod stack;
pub use stack::Stack;
pub mod diagnostics;
pub type AllocExtra = Stacks;
pub type AllocState = Stacks;
/// Extra per-allocation state.
#[derive(Clone, Debug)]
@ -500,10 +500,6 @@ impl Stacks {
})?;
Ok(())
}
fn expose_tag(&mut self, tag: BorTag) {
self.exposed_tags.insert(tag);
}
}
/// Retagging/reborrowing. There is some policy in here, such as which permissions
@ -567,10 +563,7 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
// uncovers a non-supported `extern static`.
let extra = this.get_alloc_extra(alloc_id)?;
let mut stacked_borrows = extra
.borrow_tracker
.as_ref()
.expect("We should have borrow tracking data")
.assert_sb()
.borrow_tracker_sb()
.borrow_mut();
// Note that we create a *second* `DiagnosticCxBuilder` below for the actual retag.
// FIXME: can this be done cleaner?
@ -681,12 +674,7 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
// We have to use shared references to alloc/memory_extra here since
// `visit_freeze_sensitive` needs to access the global state.
let alloc_extra = this.get_alloc_extra(alloc_id)?;
let mut stacked_borrows = alloc_extra
.borrow_tracker
.as_ref()
.expect("We should have borrow tracking data")
.assert_sb()
.borrow_mut();
let mut stacked_borrows = alloc_extra.borrow_tracker_sb().borrow_mut();
this.visit_freeze_sensitive(place, size, |mut range, frozen| {
// Adjust range.
range.start += base_offset;
@ -736,12 +724,7 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
// Note that this asserts that the allocation is mutable -- but since we are creating a
// mutable pointer, that seems reasonable.
let (alloc_extra, machine) = this.get_alloc_extra_mut(alloc_id)?;
let stacked_borrows = alloc_extra
.borrow_tracker
.as_mut()
.expect("We should have borrow tracking data")
.assert_sb_mut()
.get_mut();
let stacked_borrows = alloc_extra.borrow_tracker_sb_mut().get_mut();
let item = Item::new(new_tag, perm, protect.is_some());
let range = alloc_range(base_offset, size);
let global = machine.borrow_tracker.as_ref().unwrap().borrow();
@ -993,13 +976,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
// uncovers a non-supported `extern static`.
let alloc_extra = this.get_alloc_extra(alloc_id)?;
trace!("Stacked Borrows tag {tag:?} exposed in {alloc_id:?}");
alloc_extra
.borrow_tracker
.as_ref()
.expect("We should have borrow tracking data")
.assert_sb()
.borrow_mut()
.expose_tag(tag);
alloc_extra.borrow_tracker_sb().borrow_mut().exposed_tags.insert(tag);
}
AllocKind::Function | AllocKind::VTable | AllocKind::Dead => {
// No stacked borrows on these allocations.
@ -1011,12 +988,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
fn print_stacks(&mut self, alloc_id: AllocId) -> InterpResult<'tcx> {
let this = self.eval_context_mut();
let alloc_extra = this.get_alloc_extra(alloc_id)?;
let stacks = alloc_extra
.borrow_tracker
.as_ref()
.expect("We should have borrow tracking data")
.assert_sb()
.borrow();
let stacks = alloc_extra.borrow_tracker_sb().borrow();
for (range, stack) in stacks.stacks.iter_all() {
print!("{range:?}: [");
if let Some(bottom) = stack.unknown_bottom() {

4
src/tools/miri/src/machine.rs
View file

@ -39,7 +39,7 @@ pub const STACK_SIZE: u64 = 16 * PAGE_SIZE; // whatever
/// Extra data stored with each stack frame
pub struct FrameData<'tcx> {
/// Extra data for Stacked Borrows.
pub borrow_tracker: Option<borrow_tracker::FrameExtra>,
pub borrow_tracker: Option<borrow_tracker::FrameState>,
/// If this is Some(), then this is a special "catch unwind" frame (the frame of `try_fn`
/// called by `try`). When this frame is popped during unwinding a panic,
@ -255,7 +255,7 @@ impl ProvenanceExtra {
#[derive(Debug, Clone)]
pub struct AllocExtra {
/// Global state of the borrow tracker, if enabled.
pub borrow_tracker: Option<borrow_tracker::AllocExtra>,
pub borrow_tracker: Option<borrow_tracker::AllocState>,
/// Data race detection via the use of a vector-clock,
/// this is only added if it is enabled.
pub data_race: Option<data_race::AllocExtra>,