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Rustup #3481

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merged 17 commits into from
Apr 17, 2024
Merged

Rustup #3481

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2 changes: 1 addition & 1 deletion rust-version
Original file line number Diff line number Diff line change
@@ -1 +1 @@
803e33a4460c82581bd01d4008d0f44aef1ddfe8
c45dee5efd0c042e9d1e24559ebd0d6424d8aa70
11 changes: 6 additions & 5 deletions src/alloc_addresses/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -141,7 +141,7 @@ trait EvalContextExtPriv<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
}
}

fn addr_from_alloc_id(&self, alloc_id: AllocId) -> InterpResult<'tcx, u64> {
fn addr_from_alloc_id(&self, alloc_id: AllocId, _kind: MemoryKind) -> InterpResult<'tcx, u64> {
let ecx = self.eval_context_ref();
let mut global_state = ecx.machine.alloc_addresses.borrow_mut();
let global_state = &mut *global_state;
Expand Down Expand Up @@ -283,16 +283,17 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
}

/// Convert a relative (tcx) pointer to a Miri pointer.
fn ptr_from_rel_ptr(
fn adjust_alloc_root_pointer(
&self,
ptr: Pointer<CtfeProvenance>,
tag: BorTag,
kind: MemoryKind,
) -> InterpResult<'tcx, Pointer<Provenance>> {
let ecx = self.eval_context_ref();

let (prov, offset) = ptr.into_parts(); // offset is relative (AllocId provenance)
let alloc_id = prov.alloc_id();
let base_addr = ecx.addr_from_alloc_id(alloc_id)?;
let base_addr = ecx.addr_from_alloc_id(alloc_id, kind)?;

// Add offset with the right kind of pointer-overflowing arithmetic.
let dl = ecx.data_layout();
Expand All @@ -314,9 +315,9 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
ecx.alloc_id_from_addr(addr.bytes())?
};

// This cannot fail: since we already have a pointer with that provenance, rel_ptr_to_addr
// This cannot fail: since we already have a pointer with that provenance, adjust_alloc_root_pointer
// must have been called in the past, so we can just look up the address in the map.
let base_addr = ecx.addr_from_alloc_id(alloc_id).unwrap();
let base_addr = *ecx.machine.alloc_addresses.borrow().base_addr.get(&alloc_id).unwrap();

// Wrapping "addr - base_addr"
#[allow(clippy::cast_possible_wrap)] // we want to wrap here
Expand Down
18 changes: 9 additions & 9 deletions src/borrow_tracker/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -89,10 +89,10 @@ pub struct GlobalStateInner {
borrow_tracker_method: BorrowTrackerMethod,
/// Next unused pointer ID (tag).
next_ptr_tag: BorTag,
/// Table storing the "base" tag for each allocation.
/// The base tag is the one used for the initial pointer.
/// Table storing the "root" tag for each allocation.
/// The root tag is the one used for the initial pointer.
/// We need this in a separate table to handle cyclic statics.
base_ptr_tags: FxHashMap<AllocId, BorTag>,
root_ptr_tags: FxHashMap<AllocId, BorTag>,
/// Next unused call ID (for protectors).
next_call_id: CallId,
/// All currently protected tags.
Expand Down Expand Up @@ -175,7 +175,7 @@ impl GlobalStateInner {
GlobalStateInner {
borrow_tracker_method,
next_ptr_tag: BorTag::one(),
base_ptr_tags: FxHashMap::default(),
root_ptr_tags: FxHashMap::default(),
next_call_id: NonZero::new(1).unwrap(),
protected_tags: FxHashMap::default(),
tracked_pointer_tags,
Expand Down Expand Up @@ -213,8 +213,8 @@ impl GlobalStateInner {
}
}

pub fn base_ptr_tag(&mut self, id: AllocId, machine: &MiriMachine<'_, '_>) -> BorTag {
self.base_ptr_tags.get(&id).copied().unwrap_or_else(|| {
pub fn root_ptr_tag(&mut self, id: AllocId, machine: &MiriMachine<'_, '_>) -> BorTag {
self.root_ptr_tags.get(&id).copied().unwrap_or_else(|| {
let tag = self.new_ptr();
if self.tracked_pointer_tags.contains(&tag) {
machine.emit_diagnostic(NonHaltingDiagnostic::CreatedPointerTag(
Expand All @@ -223,14 +223,14 @@ impl GlobalStateInner {
None,
));
}
trace!("New allocation {:?} has base tag {:?}", id, tag);
self.base_ptr_tags.try_insert(id, tag).unwrap();
trace!("New allocation {:?} has rpot tag {:?}", id, tag);
self.root_ptr_tags.try_insert(id, tag).unwrap();
tag
})
}

pub fn remove_unreachable_allocs(&mut self, allocs: &LiveAllocs<'_, '_, '_>) {
self.base_ptr_tags.retain(|id, _| allocs.is_live(*id));
self.root_ptr_tags.retain(|id, _| allocs.is_live(*id));
}
}

Expand Down
12 changes: 6 additions & 6 deletions src/borrow_tracker/stacked_borrows/diagnostics.rs
Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,7 @@ fn err_sb_ub<'tcx>(
#[derive(Clone, Debug)]
pub struct AllocHistory {
id: AllocId,
base: (Item, Span),
root: (Item, Span),
creations: smallvec::SmallVec<[Creation; 1]>,
invalidations: smallvec::SmallVec<[Invalidation; 1]>,
protectors: smallvec::SmallVec<[Protection; 1]>,
Expand Down Expand Up @@ -225,7 +225,7 @@ impl AllocHistory {
pub fn new(id: AllocId, item: Item, machine: &MiriMachine<'_, '_>) -> Self {
Self {
id,
base: (item, machine.current_span()),
root: (item, machine.current_span()),
creations: SmallVec::new(),
invalidations: SmallVec::new(),
protectors: SmallVec::new(),
Expand Down Expand Up @@ -342,15 +342,15 @@ impl<'history, 'ecx, 'mir, 'tcx> DiagnosticCx<'history, 'ecx, 'mir, 'tcx> {
})
})
.or_else(|| {
// If we didn't find a retag that created this tag, it might be the base tag of
// If we didn't find a retag that created this tag, it might be the root tag of
// this allocation.
if self.history.base.0.tag() == tag {
if self.history.root.0.tag() == tag {
Some((
format!(
"{tag:?} was created here, as the base tag for {:?}",
"{tag:?} was created here, as the root tag for {:?}",
self.history.id
),
self.history.base.1.data(),
self.history.root.1.data(),
))
} else {
None
Expand Down
4 changes: 2 additions & 2 deletions src/borrow_tracker/stacked_borrows/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -518,9 +518,9 @@ impl Stacks {
// not through a pointer). That is, whenever we directly write to a local, this will pop
// everything else off the stack, invalidating all previous pointers,
// and in particular, *all* raw pointers.
MemoryKind::Stack => (state.base_ptr_tag(id, machine), Permission::Unique),
MemoryKind::Stack => (state.root_ptr_tag(id, machine), Permission::Unique),
// Everything else is shared by default.
_ => (state.base_ptr_tag(id, machine), Permission::SharedReadWrite),
_ => (state.root_ptr_tag(id, machine), Permission::SharedReadWrite),
};
Stacks::new(size, perm, base_tag, id, machine)
}
Expand Down
10 changes: 5 additions & 5 deletions src/borrow_tracker/stacked_borrows/stack.rs
Original file line number Diff line number Diff line change
Expand Up @@ -47,7 +47,7 @@ impl Stack {
let mut first_removed = None;

// We never consider removing the bottom-most tag. For stacks without an unknown
// bottom this preserves the base tag.
// bottom this preserves the root tag.
// Note that the algorithm below is based on considering the tag at read_idx - 1,
// so precisely considering the tag at index 0 for removal when we have an unknown
// bottom would complicate the implementation. The simplification of not considering
Expand Down Expand Up @@ -93,7 +93,7 @@ impl Stack {
self.unique_range = 0..self.len();
}

// Replace any Items which have been collected with the base item, a known-good value.
// Replace any Items which have been collected with the root item, a known-good value.
for i in 0..CACHE_LEN {
if self.cache.idx[i] >= first_removed {
self.cache.items[i] = self.borrows[0];
Expand Down Expand Up @@ -331,7 +331,7 @@ impl<'tcx> Stack {
self.verify_cache_consistency();
}

/// Construct a new `Stack` using the passed `Item` as the base tag.
/// Construct a new `Stack` using the passed `Item` as the root tag.
pub fn new(item: Item) -> Self {
Stack {
borrows: vec![item],
Expand Down Expand Up @@ -438,8 +438,8 @@ impl<'tcx> Stack {
let mut removed = 0;
let mut cursor = 0;
// Remove invalid entries from the cache by rotating them to the end of the cache, then
// keep track of how many invalid elements there are and overwrite them with the base tag.
// The base tag here serves as a harmless default value.
// keep track of how many invalid elements there are and overwrite them with the root tag.
// The root tag here serves as a harmless default value.
for _ in 0..CACHE_LEN - 1 {
if self.cache.idx[cursor] >= start {
self.cache.idx[cursor..CACHE_LEN - removed].rotate_left(1);
Expand Down
2 changes: 1 addition & 1 deletion src/borrow_tracker/tree_borrows/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -37,7 +37,7 @@ impl<'tcx> Tree {
_kind: MemoryKind,
machine: &MiriMachine<'_, 'tcx>,
) -> Self {
let tag = state.base_ptr_tag(id, machine); // Fresh tag for the root
let tag = state.root_ptr_tag(id, machine); // Fresh tag for the root
let span = machine.current_span();
Tree::new(tag, size, span)
}
Expand Down
22 changes: 12 additions & 10 deletions src/machine.rs
Original file line number Diff line number Diff line change
Expand Up @@ -503,7 +503,7 @@ pub struct MiriMachine<'mir, 'tcx> {
/// Crates which are considered local for the purposes of error reporting.
pub(crate) local_crates: Vec<CrateNum>,

/// Mapping extern static names to their base pointer.
/// Mapping extern static names to their pointer.
extern_statics: FxHashMap<Symbol, Pointer<Provenance>>,

/// The random number generator used for resolving non-determinism.
Expand Down Expand Up @@ -1042,14 +1042,14 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
ecx.generate_nan(inputs)
}

fn thread_local_static_base_pointer(
fn thread_local_static_pointer(
ecx: &mut MiriInterpCx<'mir, 'tcx>,
def_id: DefId,
) -> InterpResult<'tcx, Pointer<Provenance>> {
ecx.get_or_create_thread_local_alloc(def_id)
}

fn extern_static_base_pointer(
fn extern_static_pointer(
ecx: &MiriInterpCx<'mir, 'tcx>,
def_id: DefId,
) -> InterpResult<'tcx, Pointer<Provenance>> {
Expand Down Expand Up @@ -1090,7 +1090,7 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
alloc: Cow<'b, Allocation>,
kind: Option<MemoryKind>,
) -> InterpResult<'tcx, Cow<'b, Allocation<Self::Provenance, Self::AllocExtra>>> {
let kind = kind.expect("we set our STATIC_KIND so this cannot be None");
let kind = kind.expect("we set our GLOBAL_KIND so this cannot be None");
if ecx.machine.tracked_alloc_ids.contains(&id) {
ecx.emit_diagnostic(NonHaltingDiagnostic::CreatedAlloc(
id,
Expand Down Expand Up @@ -1135,7 +1135,7 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
weak_memory: buffer_alloc,
backtrace,
},
|ptr| ecx.global_base_pointer(ptr),
|ptr| ecx.global_root_pointer(ptr),
)?;

if matches!(kind, MemoryKind::Machine(kind) if kind.should_save_allocation_span()) {
Expand All @@ -1148,31 +1148,33 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
Ok(Cow::Owned(alloc))
}

fn adjust_alloc_base_pointer(
fn adjust_alloc_root_pointer(
ecx: &MiriInterpCx<'mir, 'tcx>,
ptr: Pointer<CtfeProvenance>,
kind: Option<MemoryKind>,
) -> InterpResult<'tcx, Pointer<Provenance>> {
let kind = kind.expect("we set our GLOBAL_KIND so this cannot be None");
let alloc_id = ptr.provenance.alloc_id();
if cfg!(debug_assertions) {
// The machine promises to never call us on thread-local or extern statics.
match ecx.tcx.try_get_global_alloc(alloc_id) {
Some(GlobalAlloc::Static(def_id)) if ecx.tcx.is_thread_local_static(def_id) => {
panic!("adjust_alloc_base_pointer called on thread-local static")
panic!("adjust_alloc_root_pointer called on thread-local static")
}
Some(GlobalAlloc::Static(def_id)) if ecx.tcx.is_foreign_item(def_id) => {
panic!("adjust_alloc_base_pointer called on extern static")
panic!("adjust_alloc_root_pointer called on extern static")
}
_ => {}
}
}
// FIXME: can we somehow preserve the immutability of `ptr`?
let tag = if let Some(borrow_tracker) = &ecx.machine.borrow_tracker {
borrow_tracker.borrow_mut().base_ptr_tag(alloc_id, &ecx.machine)
borrow_tracker.borrow_mut().root_ptr_tag(alloc_id, &ecx.machine)
} else {
// Value does not matter, SB is disabled
BorTag::default()
};
ecx.ptr_from_rel_ptr(ptr, tag)
ecx.adjust_alloc_root_pointer(ptr, tag, kind)
}

/// Called on `usize as ptr` casts.
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@ LL | unsafe { *x = 0 };
|
= help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
= help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
help: <TAG> was created here, as the base tag for ALLOC
help: <TAG> was created here, as the root tag for ALLOC
--> $DIR/invalidate_against_protector3.rs:LL:CC
|
LL | let ptr = alloc(Layout::for_value(&0i32)) as *mut i32;
Expand Down
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