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Fix double drop of allocator in IntoIter impl of Vec

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This commit is contained in:
Jörn Horstmann 2022-03-25 11:39:11 +01:00
parent 4ce257ff19
commit 0cf606177e
2 changed files with 10 additions and 7 deletions
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15
library/alloc/src/vec/into_iter.rs
View File

@ -8,7 +8,8 @@ use core::iter::{
FusedIterator, InPlaceIterable, SourceIter, TrustedLen, TrustedRandomAccessNoCoerce,
};
use core::marker::PhantomData;
use core::mem::{self};
use core::mem::{self, ManuallyDrop};
use core::ops::Deref;
use core::ptr::{self, NonNull};
use core::slice::{self};
@ -32,7 +33,9 @@ pub struct IntoIter<
pub(super) buf: NonNull<T>,
pub(super) phantom: PhantomData<T>,
pub(super) cap: usize,
pub(super) alloc: A,
// the drop impl reconstructs a RawVec from buf, cap and alloc
// to avoid dropping the allocator twice we need to wrap it into ManuallyDrop
pub(super) alloc: ManuallyDrop<A>,
pub(super) ptr: *const T,
pub(super) end: *const T,
}
@ -295,11 +298,11 @@ where
impl<T: Clone, A: Allocator + Clone> Clone for IntoIter<T, A> {
#[cfg(not(test))]
fn clone(&self) -> Self {
self.as_slice().to_vec_in(self.alloc.clone()).into_iter()
self.as_slice().to_vec_in(self.alloc.deref().clone()).into_iter()
}
#[cfg(test)]
fn clone(&self) -> Self {
crate::slice::to_vec(self.as_slice(), self.alloc.clone()).into_iter()
crate::slice::to_vec(self.as_slice(), self.alloc.deref().clone()).into_iter()
}
}
@ -311,8 +314,8 @@ unsafe impl<#[may_dangle] T, A: Allocator> Drop for IntoIter<T, A> {
impl<T, A: Allocator> Drop for DropGuard<'_, T, A> {
fn drop(&mut self) {
unsafe {
// `IntoIter::alloc` is not used anymore after this
let alloc = ptr::read(&self.0.alloc);
// `IntoIter::alloc` is not used anymore after this and will be dropped by RawVec
let alloc = ManuallyDrop::into_inner(ptr::read(&self.0.alloc));
// RawVec handles deallocation
let _ = RawVec::from_raw_parts_in(self.0.buf.as_ptr(), self.0.cap, alloc);
}

2
library/alloc/src/vec/mod.rs
View File

@ -2575,7 +2575,7 @@ impl<T, A: Allocator> IntoIterator for Vec<T, A> {
fn into_iter(self) -> IntoIter<T, A> {
unsafe {
let mut me = ManuallyDrop::new(self);
let alloc = ptr::read(me.allocator());
let alloc = ManuallyDrop::new(ptr::read(me.allocator()));
let begin = me.as_mut_ptr();
let end = if mem::size_of::<T>() == 0 {
arith_offset(begin as *const i8, me.len() as isize) as *const T