diff --git a/src/liballoc/tests/vec.rs b/src/liballoc/tests/vec.rs index 9c4ac52acac2a..6321e7154e7d0 100644 --- a/src/liballoc/tests/vec.rs +++ b/src/liballoc/tests/vec.rs @@ -1351,17 +1351,26 @@ fn test_try_reserve_exact() { } #[test] -fn test_stable_push_pop() { +fn test_stable_pointers() { + /// Pull an element from the iterator, then drop it. + /// Useful to cover both the `next` and `drop` paths of an iterator. + fn next_then_drop(mut i: I) { + i.next().unwrap(); + drop(i); + } + // Test that, if we reserved enough space, adding and removing elements does not // invalidate references into the vector (such as `v0`). This test also // runs in Miri, which would detect such problems. - let mut v = Vec::with_capacity(10); + let mut v = Vec::with_capacity(128); v.push(13); - // laundering the lifetime -- we take care that `v` does not reallocate, so that's okay. - let v0 = unsafe { &*(&v[0] as *const _) }; - + // Laundering the lifetime -- we take care that `v` does not reallocate, so that's okay. + let v0 = &mut v[0]; + let v0 = unsafe { &mut *(v0 as *mut _) }; // Now do a bunch of things and occasionally use `v0` again to assert it is still valid. + + // Pushing/inserting and popping/removing v.push(1); v.push(2); v.insert(1, 1); @@ -1369,6 +1378,58 @@ fn test_stable_push_pop() { v.remove(1); v.pop().unwrap(); assert_eq!(*v0, 13); + v.push(1); + v.swap_remove(1); + assert_eq!(v.len(), 2); + v.swap_remove(1); // swap_remove the last element + assert_eq!(*v0, 13); + + // Appending + v.append(&mut vec![27, 19]); + assert_eq!(*v0, 13); + + // Extending + v.extend_from_slice(&[1, 2]); + v.extend(&[1, 2]); // `slice::Iter` (with `T: Copy`) specialization + v.extend(vec![2, 3]); // `vec::IntoIter` specialization + v.extend(std::iter::once(3)); // `TrustedLen` specialization + v.extend(std::iter::empty::()); // `TrustedLen` specialization with empty iterator + v.extend(std::iter::once(3).filter(|_| true)); // base case + v.extend(std::iter::once(&3)); // `cloned` specialization + assert_eq!(*v0, 13); + + // Truncation + v.truncate(2); + assert_eq!(*v0, 13); + + // Resizing + v.resize_with(v.len() + 10, || 42); + assert_eq!(*v0, 13); + v.resize_with(2, || panic!()); + assert_eq!(*v0, 13); + + // No-op reservation + v.reserve(32); + v.reserve_exact(32); + assert_eq!(*v0, 13); + + // Partial draining + v.resize_with(10, || 42); + next_then_drop(v.drain(5..)); + assert_eq!(*v0, 13); + + // Splicing + v.resize_with(10, || 42); + next_then_drop(v.splice(5.., vec![1, 2, 3, 4, 5])); // empty tail after range + assert_eq!(*v0, 13); + next_then_drop(v.splice(5..8, vec![1])); // replacement is smaller than original range + assert_eq!(*v0, 13); + next_then_drop(v.splice(5..6, vec![1; 10].into_iter().filter(|_| true))); // lower bound not exact + assert_eq!(*v0, 13); + + // Smoke test that would fire even outside Miri if an actual relocation happened. + *v0 -= 13; + assert_eq!(v[0], 0); } // https://github.com/rust-lang/rust/pull/49496 introduced specialization based on: diff --git a/src/liballoc/vec.rs b/src/liballoc/vec.rs index e171edef73609..aedb3724409fd 100644 --- a/src/liballoc/vec.rs +++ b/src/liballoc/vec.rs @@ -739,7 +739,8 @@ impl Vec { if len > self.len { return; } - let s = self.get_unchecked_mut(len..) as *mut _; + let remaining_len = self.len - len; + let s = slice::from_raw_parts_mut(self.as_mut_ptr().add(len), remaining_len); self.len = len; ptr::drop_in_place(s); } @@ -962,13 +963,15 @@ impl Vec { #[inline] #[stable(feature = "rust1", since = "1.0.0")] pub fn swap_remove(&mut self, index: usize) -> T { + let len = self.len(); + assert!(index < len); unsafe { // We replace self[index] with the last element. Note that if the - // bounds check on hole succeeds there must be a last element (which + // bounds check above succeeds there must be a last element (which // can be self[index] itself). - let hole: *mut T = &mut self[index]; - let last = ptr::read(self.get_unchecked(self.len - 1)); - self.len -= 1; + let last = ptr::read(self.as_ptr().add(len - 1)); + let hole: *mut T = self.as_mut_ptr().add(index); + self.set_len(len - 1); ptr::replace(hole, last) } } @@ -1199,7 +1202,7 @@ impl Vec { } else { unsafe { self.len -= 1; - Some(ptr::read(self.get_unchecked(self.len()))) + Some(ptr::read(self.as_ptr().add(self.len()))) } } } @@ -2019,7 +2022,7 @@ where let (lower, _) = iterator.size_hint(); let mut vector = Vec::with_capacity(lower.saturating_add(1)); unsafe { - ptr::write(vector.get_unchecked_mut(0), element); + ptr::write(vector.as_mut_ptr(), element); vector.set_len(1); } vector @@ -2122,8 +2125,9 @@ where self.reserve(slice.len()); unsafe { let len = self.len(); + let dst_slice = slice::from_raw_parts_mut(self.as_mut_ptr().add(len), slice.len()); + dst_slice.copy_from_slice(slice); self.set_len(len + slice.len()); - self.get_unchecked_mut(len..).copy_from_slice(slice); } } } @@ -2144,7 +2148,7 @@ impl Vec { self.reserve(lower.saturating_add(1)); } unsafe { - ptr::write(self.get_unchecked_mut(len), element); + ptr::write(self.as_mut_ptr().add(len), element); // NB can't overflow since we would have had to alloc the address space self.set_len(len + 1); }