Merge pull request #26161 from alexcrichton/beta-backport

Backport accepted PRs to beta

Author: brson

mk/main.mk

@@ -74,9 +74,6 @@ ifneq ($(wildcard $(subst $(SPACE),\$(SPACE),$(CFG_GIT_DIR))),)
 endif
 endif
 
-CFG_BUILD_DATE = $(shell date +%F)
-CFG_VERSION += (built $(CFG_BUILD_DATE))
-
 # Windows exe's need numeric versions - don't use anything but
 # numbers and dots here
 CFG_VERSION_WIN = $(CFG_RELEASE_NUM)
@@ -333,7 +330,6 @@ endif
 ifdef CFG_VER_HASH
 export CFG_VER_HASH
 endif
-export CFG_BUILD_DATE
 export CFG_VERSION
 export CFG_VERSION_WIN
 export CFG_RELEASE

src/libcollections/binary_heap.rs

@@ -153,7 +153,7 @@
 use core::prelude::*;
 
 use core::iter::{FromIterator};
-use core::mem::{zeroed, replace, swap};
+use core::mem::swap;
 use core::ptr;
 
 use slice;
@@ -484,46 +484,42 @@ impl<T: Ord> BinaryHeap<T> {
 
     // The implementations of sift_up and sift_down use unsafe blocks in
     // order to move an element out of the vector (leaving behind a
-    // zeroed element), shift along the others and move it back into the
-    // vector over the junk element. This reduces the constant factor
-    // compared to using swaps, which involves twice as many moves.
-    fn sift_up(&mut self, start: usize, mut pos: usize) {
+    // hole), shift along the others and move the removed element back into the
+    // vector at the final location of the hole.
+    // The `Hole` type is used to represent this, and make sure
+    // the hole is filled back at the end of its scope, even on panic.
+    // Using a hole reduces the constant factor compared to using swaps,
+    // which involves twice as many moves.
+    fn sift_up(&mut self, start: usize, pos: usize) {
         unsafe {
-            let new = replace(&mut self.data[pos], zeroed());
+            // Take out the value at `pos` and create a hole.
+            let mut hole = Hole::new(&mut self.data, pos);
 
-            while pos > start {
-                let parent = (pos - 1) >> 1;
-
-                if new <= self.data[parent] { break; }
-
-                let x = replace(&mut self.data[parent], zeroed());
-                ptr::write(&mut self.data[pos], x);
-                pos = parent;
+            while hole.pos() > start {
+                let parent = (hole.pos() - 1) / 2;
+                if hole.removed() <= hole.get(parent) { break }
+                hole.move_to(parent);
             }
-            ptr::write(&mut self.data[pos], new);
         }
     }
 
     fn sift_down_range(&mut self, mut pos: usize, end: usize) {
+        let start = pos;
         unsafe {
-            let start = pos;
-            let new = replace(&mut self.data[pos], zeroed());
-
+            let mut hole = Hole::new(&mut self.data, pos);
             let mut child = 2 * pos + 1;
             while child < end {
                 let right = child + 1;
-                if right < end && !(self.data[child] > self.data[right]) {
+                if right < end && !(hole.get(child) > hole.get(right)) {
                     child = right;
                 }
-                let x = replace(&mut self.data[child], zeroed());
-                ptr::write(&mut self.data[pos], x);
-                pos = child;
-                child = 2 * pos + 1;
+                hole.move_to(child);
+                child = 2 * hole.pos() + 1;
             }
 
-            ptr::write(&mut self.data[pos], new);
-            self.sift_up(start, pos);
+            pos = hole.pos;
         }
+        self.sift_up(start, pos);
     }
 
     fn sift_down(&mut self, pos: usize) {
@@ -554,6 +550,73 @@ impl<T: Ord> BinaryHeap<T> {
     pub fn clear(&mut self) { self.drain(); }
 }
 
+/// Hole represents a hole in a slice i.e. an index without valid value
+/// (because it was moved from or duplicated).
+/// In drop, `Hole` will restore the slice by filling the hole
+/// position with the value that was originally removed.
+struct Hole<'a, T: 'a> {
+    data: &'a mut [T],
+    /// `elt` is always `Some` from new until drop.
+    elt: Option<T>,
+    pos: usize,
+}
+
+impl<'a, T> Hole<'a, T> {
+    /// Create a new Hole at index `pos`.
+    fn new(data: &'a mut [T], pos: usize) -> Self {
+        unsafe {
+            let elt = ptr::read(&data[pos]);
+            Hole {
+                data: data,
+                elt: Some(elt),
+                pos: pos,
+            }
+        }
+    }
+
+    #[inline(always)]
+    fn pos(&self) -> usize { self.pos }
+
+    /// Return a reference to the element removed
+    #[inline(always)]
+    fn removed(&self) -> &T {
+        self.elt.as_ref().unwrap()
+    }
+
+    /// Return a reference to the element at `index`.
+    ///
+    /// Panics if the index is out of bounds.
+    ///
+    /// Unsafe because index must not equal pos.
+    #[inline(always)]
+    unsafe fn get(&self, index: usize) -> &T {
+        debug_assert!(index != self.pos);
+        &self.data[index]
+    }
+
+    /// Move hole to new location
+    ///
+    /// Unsafe because index must not equal pos.
+    #[inline(always)]
+    unsafe fn move_to(&mut self, index: usize) {
+        debug_assert!(index != self.pos);
+        let index_ptr: *const _ = &self.data[index];
+        let hole_ptr = &mut self.data[self.pos];
+        ptr::copy_nonoverlapping(index_ptr, hole_ptr, 1);
+        self.pos = index;
+    }
+}
+
+impl<'a, T> Drop for Hole<'a, T> {
+    fn drop(&mut self) {
+        // fill the hole again
+        unsafe {
+            let pos = self.pos;
+            ptr::write(&mut self.data[pos], self.elt.take().unwrap());
+        }
+    }
+}
+
 /// `BinaryHeap` iterator.
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Iter <'a, T: 'a> {

src/libcollections/linked_list.rs

@@ -616,7 +616,13 @@ impl<T> LinkedList<T> {
             length: len - at
         };
 
+        // Swap split_node.next with list_head (which is None), nulling out split_node.next,
+        // as it is the new tail.
         mem::swap(&mut split_node.resolve().unwrap().next, &mut splitted_list.list_head);
+        // Null out list_head.prev. Note this `unwrap` won't fail because if at == len
+        // we already branched out at the top of the fn to return the empty list.
+        splitted_list.list_head.as_mut().unwrap().prev = Rawlink::none();
+        // Fix the tail ptr
         self.list_tail = split_node;
         self.length = at;
 
@@ -1082,6 +1088,26 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_26021() {
+        use std::iter::ExactSizeIterator;
+        // There was a bug in split_off that failed to null out the RHS's head's prev ptr.
+        // This caused the RHS's dtor to walk up into the LHS at drop and delete all of
+        // its nodes.
+        //
+        // https://github.com/rust-lang/rust/issues/26021
+        let mut v1 = LinkedList::new();
+        v1.push_front(1u8);
+        v1.push_front(1u8);
+        v1.push_front(1u8);
+        v1.push_front(1u8);
+        let _ = v1.split_off(3); // Dropping this now should not cause laundry consumption
+        assert_eq!(v1.len(), 3);
+
+        assert_eq!(v1.iter().len(), 3);
+        assert_eq!(v1.iter().collect::<Vec<_>>().len(), 3);
+    }
+
     #[cfg(test)]
     fn fuzz_test(sz: i32) {
         let mut m: LinkedList<_> = LinkedList::new();

src/libcore/iter.rs

@@ -1370,7 +1370,7 @@ impl<T: Clone> MinMaxResult<T> {
 }
 
 /// An iterator that clones the elements of an underlying iterator
-#[unstable(feature = "core", reason = "recent addition")]
+#[stable(feature = "iter_cloned", since = "1.1.0")]
 #[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
 #[derive(Clone)]
 pub struct Cloned<I> {

src/libcore/num/mod.rs

@@ -563,13 +563,22 @@ macro_rules! int_impl {
             acc
         }
 
-        /// Computes the absolute value of `self`. `Int::min_value()` will be
-        /// returned if the number is `Int::min_value()`.
+        /// Computes the absolute value of `self`.
+        ///
+        /// # Overflow behavior
+        ///
+        /// The absolute value of `i32::min_value()` cannot be represented as an
+        /// `i32`, and attempting to calculate it will cause an overflow. This
+        /// means that code in debug mode will trigger a panic on this case and
+        /// optimized code will return `i32::min_value()` without a panic.
         #[stable(feature = "rust1", since = "1.0.0")]
         #[inline]
         pub fn abs(self) -> $T {
             if self.is_negative() {
-                self.wrapping_neg()
+                // Note that the #[inline] above means that the overflow
+                // semantics of this negation depend on the crate we're being
+                // inlined into.
+                -self
             } else {
                 self
             }

src/librustc_driver/lib.rs

@@ -483,10 +483,6 @@ pub fn commit_date_str() -> Option<&'static str> {
     option_env!("CFG_VER_DATE")
 }
 
-pub fn build_date_str() -> Option<&'static str> {
-    option_env!("CFG_BUILD_DATE")
-}
-
 /// Prints version information and returns None on success or an error
 /// message on panic.
 pub fn version(binary: &str, matches: &getopts::Matches) {
@@ -498,7 +494,6 @@ pub fn version(binary: &str, matches: &getopts::Matches) {
         println!("binary: {}", binary);
         println!("commit-hash: {}", unw(commit_hash_str()));
         println!("commit-date: {}", unw(commit_date_str()));
-        println!("build-date: {}", unw(build_date_str()));
         println!("host: {}", config::host_triple());
         println!("release: {}", unw(release_str()));
     }

src/libstd/net/mod.rs

@@ -19,7 +19,7 @@ use sys_common::net as net_imp;
 
 pub use self::ip::{IpAddr, Ipv4Addr, Ipv6Addr, Ipv6MulticastScope};
 pub use self::addr::{SocketAddr, SocketAddrV4, SocketAddrV6, ToSocketAddrs};
-pub use self::tcp::{TcpStream, TcpListener};
+pub use self::tcp::{TcpStream, TcpListener, Incoming};
 pub use self::udp::UdpSocket;
 pub use self::parser::AddrParseError;
 

src/test/run-pass/binary-heap-panic-safe.rs

@@ -0,0 +1,108 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(std_misc, collections, catch_panic, rand)]
+
+use std::__rand::{thread_rng, Rng};
+use std::thread;
+
+use std::collections::BinaryHeap;
+use std::cmp;
+use std::sync::Arc;
+use std::sync::Mutex;
+use std::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
+
+static DROP_COUNTER: AtomicUsize = ATOMIC_USIZE_INIT;
+
+// old binaryheap failed this test
+//
+// Integrity means that all elements are present after a comparison panics,
+// even if the order may not be correct.
+//
+// Destructors must be called exactly once per element.
+fn test_integrity() {
+    #[derive(Eq, PartialEq, Ord, Clone, Debug)]
+    struct PanicOrd<T>(T, bool);
+
+    impl<T> Drop for PanicOrd<T> {
+        fn drop(&mut self) {
+            // update global drop count
+            DROP_COUNTER.fetch_add(1, Ordering::SeqCst);
+        }
+    }
+
+    impl<T: PartialOrd> PartialOrd for PanicOrd<T> {
+        fn partial_cmp(&self, other: &Self) -> Option<cmp::Ordering> {
+            if self.1 || other.1 {
+                panic!("Panicking comparison");
+            }
+            self.0.partial_cmp(&other.0)
+        }
+    }
+    let mut rng = thread_rng();
+    const DATASZ: usize = 32;
+    const NTEST: usize = 10;
+
+    // don't use 0 in the data -- we want to catch the zeroed-out case.
+    let data = (1..DATASZ + 1).collect::<Vec<_>>();
+
+    // since it's a fuzzy test, run several tries.
+    for _ in 0..NTEST {
+        for i in 1..DATASZ + 1 {
+            DROP_COUNTER.store(0, Ordering::SeqCst);
+
+            let mut panic_ords: Vec<_> = data.iter()
+                                             .filter(|&&x| x != i)
+                                             .map(|&x| PanicOrd(x, false))
+                                             .collect();
+            let panic_item = PanicOrd(i, true);
+
+            // heapify the sane items
+            rng.shuffle(&mut panic_ords);
+            let heap = Arc::new(Mutex::new(BinaryHeap::from_vec(panic_ords)));
+            let inner_data;
+
+            {
+                let heap_ref = heap.clone();
+
+
+                // push the panicking item to the heap and catch the panic
+                let thread_result = thread::catch_panic(move || {
+                    heap.lock().unwrap().push(panic_item);
+                });
+                assert!(thread_result.is_err());
+
+                // Assert no elements were dropped
+                let drops = DROP_COUNTER.load(Ordering::SeqCst);
+                //assert!(drops == 0, "Must not drop items. drops={}", drops);
+
+                {
+                    // now fetch the binary heap's data vector
+                    let mutex_guard = match heap_ref.lock() {
+                        Ok(x) => x,
+                        Err(poison) => poison.into_inner(),
+                    };
+                    inner_data = mutex_guard.clone().into_vec();
+                }
+            }
+            let drops = DROP_COUNTER.load(Ordering::SeqCst);
+            assert_eq!(drops, DATASZ);
+
+            let mut data_sorted = inner_data.into_iter().map(|p| p.0).collect::<Vec<_>>();
+            data_sorted.sort();
+            assert_eq!(data_sorted, data);
+        }
+    }
+}
+
+fn main() {
+    test_integrity();
+}
+