}
impl<'mir, 'tcx> GlobalState {
- pub fn int_to_ptr(
- int: u64,
+ pub fn ptr_from_addr(
+ addr: u64,
memory: &Memory<'mir, 'tcx, Evaluator<'mir, 'tcx>>,
- ) -> InterpResult<'tcx, Pointer<Tag>> {
+ ) -> Pointer<Option<Tag>> {
+ trace!("Casting 0x{:x} to a pointer", addr);
let global_state = memory.extra.intptrcast.borrow();
- let pos = global_state.int_to_ptr_map.binary_search_by_key(&int, |(addr, _)| *addr);
-
- // The int must be in-bounds after being cast to a pointer, so we error
- // with `CheckInAllocMsg::InboundsTest`.
- Ok(match pos {
- Ok(pos) => {
- let (_, alloc_id) = global_state.int_to_ptr_map[pos];
- // `int` is equal to the starting address for an allocation, the offset should be
- // zero. The pointer is untagged because it was created from a cast
- Pointer::new_with_tag(alloc_id, Size::from_bytes(0), Tag::Untagged)
- }
- Err(0) => throw_ub!(DanglingIntPointer(int, CheckInAllocMsg::InboundsTest)),
+ let pos = global_state.int_to_ptr_map.binary_search_by_key(&addr, |(addr, _)| *addr);
+
+ let alloc_id = match pos {
+ Ok(pos) => Some(global_state.int_to_ptr_map[pos].1),
+ Err(0) => None,
Err(pos) => {
// This is the largest of the adresses smaller than `int`,
// i.e. the greatest lower bound (glb)
let (glb, alloc_id) = global_state.int_to_ptr_map[pos - 1];
- // This never overflows because `int >= glb`
- let offset = int - glb;
- // If the offset exceeds the size of the allocation, this access is illegal
- if offset <= memory.get_size_and_align(alloc_id, AllocCheck::MaybeDead)?.0.bytes() {
- // This pointer is untagged because it was created from a cast
- Pointer::new_with_tag(alloc_id, Size::from_bytes(offset), Tag::Untagged)
+ // This never overflows because `addr >= glb`
+ let offset = addr - glb;
+ // If the offset exceeds the size of the allocation, don't use this `alloc_id`.
+ if offset
+ <= memory.get_size_and_align(alloc_id, AllocCheck::MaybeDead).unwrap().0.bytes()
+ {
+ Some(alloc_id)
} else {
- throw_ub!(DanglingIntPointer(int, CheckInAllocMsg::InboundsTest))
+ None
}
}
- })
+ };
+ // Pointers created from integers are untagged.
+ Pointer::new(
+ alloc_id.map(|alloc_id| Tag { alloc_id, sb: SbTag::Untagged }),
+ Size::from_bytes(addr),
+ )
}
- pub fn ptr_to_int(
- ptr: Pointer<Tag>,
+ fn alloc_base_addr(
memory: &Memory<'mir, 'tcx, Evaluator<'mir, 'tcx>>,
- ) -> InterpResult<'tcx, u64> {
+ alloc_id: AllocId,
+ ) -> u64 {
let mut global_state = memory.extra.intptrcast.borrow_mut();
let global_state = &mut *global_state;
- let id = ptr.alloc_id;
-
- // There is nothing wrong with a raw pointer being cast to an integer only after
- // it became dangling. Hence `MaybeDead`.
- let (size, align) = memory.get_size_and_align(id, AllocCheck::MaybeDead)?;
- let base_addr = match global_state.base_addr.entry(id) {
+ match global_state.base_addr.entry(alloc_id) {
Entry::Occupied(entry) => *entry.get(),
Entry::Vacant(entry) => {
+ // There is nothing wrong with a raw pointer being cast to an integer only after
+ // it became dangling. Hence `MaybeDead`.
+ let (size, align) =
+ memory.get_size_and_align(alloc_id, AllocCheck::MaybeDead).unwrap();
+
// This allocation does not have a base address yet, pick one.
// Leave some space to the previous allocation, to give it some chance to be less aligned.
let slack = {
let base_addr = Self::align_addr(base_addr, align.bytes());
entry.insert(base_addr);
trace!(
- "Assigning base address {:#x} to allocation {:?} (slack: {}, align: {})",
+ "Assigning base address {:#x} to allocation {:?} (size: {}, align: {}, slack: {})",
base_addr,
- id,
- slack,
+ alloc_id,
+ size.bytes(),
align.bytes(),
+ slack,
);
// Remember next base address. If this allocation is zero-sized, leave a gap
global_state.next_base_addr = base_addr.checked_add(max(size.bytes(), 1)).unwrap();
// Given that `next_base_addr` increases in each allocation, pushing the
// corresponding tuple keeps `int_to_ptr_map` sorted
- global_state.int_to_ptr_map.push((base_addr, id));
+ global_state.int_to_ptr_map.push((base_addr, alloc_id));
base_addr
}
- };
+ }
+ }
+
+ /// Convert a relative (tcx) pointer to an absolute address.
+ pub fn rel_ptr_to_addr(
+ memory: &Memory<'mir, 'tcx, Evaluator<'mir, 'tcx>>,
+ ptr: Pointer<AllocId>,
+ ) -> u64 {
+ let (alloc_id, offset) = ptr.into_parts(); // offset is relative
+ let base_addr = GlobalState::alloc_base_addr(memory, alloc_id);
- // Sanity check that the base address is aligned.
- debug_assert_eq!(base_addr % align.bytes(), 0);
// Add offset with the right kind of pointer-overflowing arithmetic.
let dl = memory.data_layout();
- Ok(dl.overflowing_offset(base_addr, ptr.offset.bytes()).0)
+ dl.overflowing_offset(base_addr, offset.bytes()).0
+ }
+
+ pub fn abs_ptr_to_rel(
+ memory: &Memory<'mir, 'tcx, Evaluator<'mir, 'tcx>>,
+ ptr: Pointer<Tag>,
+ ) -> Size {
+ let (tag, addr) = ptr.into_parts(); // addr is absolute
+ let base_addr = GlobalState::alloc_base_addr(memory, tag.alloc_id);
+
+ // Wrapping "addr - base_addr"
+ let dl = memory.data_layout();
+ let neg_base_addr = (base_addr as i64).wrapping_neg();
+ Size::from_bytes(dl.overflowing_signed_offset(addr.bytes(), neg_base_addr).0)
}
/// Shifts `addr` to make it aligned with `align` by rounding `addr` to the smallest multiple
projects / rust.git / blobdiff