diff options
Diffstat (limited to 'compiler/rustc_middle/src/mir/interpret/allocation.rs')
| -rw-r--r-- | compiler/rustc_middle/src/mir/interpret/allocation.rs | 84 |
1 files changed, 50 insertions, 34 deletions
diff --git a/compiler/rustc_middle/src/mir/interpret/allocation.rs b/compiler/rustc_middle/src/mir/interpret/allocation.rs index 27ead514531..2ea92a39d48 100644 --- a/compiler/rustc_middle/src/mir/interpret/allocation.rs +++ b/compiler/rustc_middle/src/mir/interpret/allocation.rs @@ -306,8 +306,6 @@ pub enum AllocError { ScalarSizeMismatch(ScalarSizeMismatch), /// Encountered a pointer where we needed raw bytes. ReadPointerAsInt(Option<BadBytesAccess>), - /// Partially overwriting a pointer. - OverwritePartialPointer(Size), /// Partially copying a pointer. ReadPartialPointer(Size), /// Using uninitialized data where it is not allowed. @@ -331,9 +329,6 @@ impl AllocError { ReadPointerAsInt(info) => InterpErrorKind::Unsupported( UnsupportedOpInfo::ReadPointerAsInt(info.map(|b| (alloc_id, b))), ), - OverwritePartialPointer(offset) => InterpErrorKind::Unsupported( - UnsupportedOpInfo::OverwritePartialPointer(Pointer::new(alloc_id, offset)), - ), ReadPartialPointer(offset) => InterpErrorKind::Unsupported( UnsupportedOpInfo::ReadPartialPointer(Pointer::new(alloc_id, offset)), ), @@ -633,11 +628,11 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes> &mut self, cx: &impl HasDataLayout, range: AllocRange, - ) -> AllocResult<&mut [u8]> { + ) -> &mut [u8] { self.mark_init(range, true); - self.provenance.clear(range, cx)?; + self.provenance.clear(range, cx); - Ok(&mut self.bytes[range.start.bytes_usize()..range.end().bytes_usize()]) + &mut self.bytes[range.start.bytes_usize()..range.end().bytes_usize()] } /// A raw pointer variant of `get_bytes_unchecked_for_overwrite` that avoids invalidating existing immutable aliases @@ -646,15 +641,15 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes> &mut self, cx: &impl HasDataLayout, range: AllocRange, - ) -> AllocResult<*mut [u8]> { + ) -> *mut [u8] { self.mark_init(range, true); - self.provenance.clear(range, cx)?; + self.provenance.clear(range, cx); assert!(range.end().bytes_usize() <= self.bytes.len()); // need to do our own bounds-check // Crucially, we go via `AllocBytes::as_mut_ptr`, not `AllocBytes::deref_mut`. let begin_ptr = self.bytes.as_mut_ptr().wrapping_add(range.start.bytes_usize()); let len = range.end().bytes_usize() - range.start.bytes_usize(); - Ok(ptr::slice_from_raw_parts_mut(begin_ptr, len)) + ptr::slice_from_raw_parts_mut(begin_ptr, len) } /// This gives direct mutable access to the entire buffer, just exposing their internal state @@ -723,26 +718,45 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes> let ptr = Pointer::new(prov, Size::from_bytes(bits)); return Ok(Scalar::from_pointer(ptr, cx)); } - - // If we can work on pointers byte-wise, join the byte-wise provenances. - if Prov::OFFSET_IS_ADDR { - let mut prov = self.provenance.get(range.start, cx); + // The other easy case is total absence of provenance. + if self.provenance.range_empty(range, cx) { + return Ok(Scalar::from_uint(bits, range.size)); + } + // If we get here, we have to check per-byte provenance, and join them together. + let prov = 'prov: { + // Initialize with first fragment. Must have index 0. + let Some((mut joint_prov, 0)) = self.provenance.get_byte(range.start, cx) else { + break 'prov None; + }; + // Update with the remaining fragments. for offset in Size::from_bytes(1)..range.size { - let this_prov = self.provenance.get(range.start + offset, cx); - prov = Prov::join(prov, this_prov); + // Ensure there is provenance here and it has the right index. + let Some((frag_prov, frag_idx)) = + self.provenance.get_byte(range.start + offset, cx) + else { + break 'prov None; + }; + // Wildcard provenance is allowed to come with any index (this is needed + // for Miri's native-lib mode to work). + if u64::from(frag_idx) != offset.bytes() && Some(frag_prov) != Prov::WILDCARD { + break 'prov None; + } + // Merge this byte's provenance with the previous ones. + joint_prov = match Prov::join(joint_prov, frag_prov) { + Some(prov) => prov, + None => break 'prov None, + }; } - // Now use this provenance. - let ptr = Pointer::new(prov, Size::from_bytes(bits)); - return Ok(Scalar::from_maybe_pointer(ptr, cx)); - } else { - // Without OFFSET_IS_ADDR, the only remaining case we can handle is total absence of - // provenance. - if self.provenance.range_empty(range, cx) { - return Ok(Scalar::from_uint(bits, range.size)); - } - // Else we have mixed provenance, that doesn't work. + break 'prov Some(joint_prov); + }; + if prov.is_none() && !Prov::OFFSET_IS_ADDR { + // There are some bytes with provenance here but overall the provenance does not add up. + // We need `OFFSET_IS_ADDR` to fall back to no-provenance here; without that option, we must error. return Err(AllocError::ReadPartialPointer(range.start)); } + // We can use this provenance. + let ptr = Pointer::new(prov, Size::from_bytes(bits)); + return Ok(Scalar::from_maybe_pointer(ptr, cx)); } else { // We are *not* reading a pointer. // If we can just ignore provenance or there is none, that's easy. @@ -782,7 +796,7 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes> let endian = cx.data_layout().endian; // Yes we do overwrite all the bytes in `dst`. - let dst = self.get_bytes_unchecked_for_overwrite(cx, range)?; + let dst = self.get_bytes_unchecked_for_overwrite(cx, range); write_target_uint(endian, dst, bytes).unwrap(); // See if we have to also store some provenance. @@ -795,10 +809,9 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes> } /// Write "uninit" to the given memory range. - pub fn write_uninit(&mut self, cx: &impl HasDataLayout, range: AllocRange) -> AllocResult { + pub fn write_uninit(&mut self, cx: &impl HasDataLayout, range: AllocRange) { self.mark_init(range, false); - self.provenance.clear(range, cx)?; - Ok(()) + self.provenance.clear(range, cx); } /// Mark all bytes in the given range as initialised and reset the provenance @@ -817,9 +830,12 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes> } /// Remove all provenance in the given memory range. - pub fn clear_provenance(&mut self, cx: &impl HasDataLayout, range: AllocRange) -> AllocResult { - self.provenance.clear(range, cx)?; - return Ok(()); + pub fn clear_provenance(&mut self, cx: &impl HasDataLayout, range: AllocRange) { + self.provenance.clear(range, cx); + } + + pub fn provenance_merge_bytes(&mut self, cx: &impl HasDataLayout) -> bool { + self.provenance.merge_bytes(cx) } /// Applies a previously prepared provenance copy. |