Auto merge of #56581 - kennytm:rollup, r=kennytm

Rollup of 7 pull requests

Successful merges:

 - #56000 (Add Armv8-M Mainline targets)
 - #56250 (Introduce ptr::hash for references)
 - #56434 (Improve query cycle errors for parallel queries)
 - #56516 (Replace usages of `..i + 1` ranges with `..=i`.)
 - #56555 (Send textual profile data to stderr, not stdout)
 - #56561 (Fix bug in from_key_hashed_nocheck)
 - #56574 (Fix a stutter in the docs for slice::exact_chunks)

Failed merges:

r? @ghost

src/liballoc/collections/vec_deque.rs

@@ -2795,7 +2795,7 @@ mod tests {
             // 0, 1, 2, .., len - 1
             let expected = (0..).take(len).collect::<VecDeque<_>>();
             for tail_pos in 0..cap {
-                for to_remove in 0..len + 1 {
+                for to_remove in 0..=len {
                     tester.tail = tail_pos;
                     tester.head = tail_pos;
                     for i in 0..len {
@@ -2821,10 +2821,10 @@ mod tests {
         let mut tester: VecDeque<usize> = VecDeque::with_capacity(7);
 
         let cap = tester.capacity();
-        for len in 0..cap + 1 {
-            for tail in 0..cap + 1 {
-                for drain_start in 0..len + 1 {
-                    for drain_end in drain_start..len + 1 {
+        for len in 0..=cap {
+            for tail in 0..=cap {
+                for drain_start in 0..=len {
+                    for drain_end in drain_start..=len {
                         tester.tail = tail;
                         tester.head = tail;
                         for i in 0..len {
@@ -2866,10 +2866,10 @@ mod tests {
         tester.reserve(63);
         let max_cap = tester.capacity();
 
-        for len in 0..cap + 1 {
+        for len in 0..=cap {
             // 0, 1, 2, .., len - 1
             let expected = (0..).take(len).collect::<VecDeque<_>>();
-            for tail_pos in 0..max_cap + 1 {
+            for tail_pos in 0..=max_cap {
                 tester.tail = tail_pos;
                 tester.head = tail_pos;
                 tester.reserve(63);
@@ -2899,7 +2899,7 @@ mod tests {
         // len is the length *before* splitting
         for len in 0..cap {
             // index to split at
-            for at in 0..len + 1 {
+            for at in 0..=len {
                 // 0, 1, 2, .., at - 1 (may be empty)
                 let expected_self = (0..).take(at).collect::<VecDeque<_>>();
                 // at, at + 1, .., len - 1 (may be empty)
@@ -2927,7 +2927,7 @@ mod tests {
     fn test_from_vec() {
         use vec::Vec;
         for cap in 0..35 {
-            for len in 0..cap + 1 {
+            for len in 0..=cap {
                 let mut vec = Vec::with_capacity(cap);
                 vec.extend(0..len);
 

src/liballoc/tests/binary_heap.rs

@@ -318,11 +318,11 @@ fn panic_safe() {
     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<_>>();
+    let data = (1..=DATASZ).collect::<Vec<_>>();
 
     // since it's a fuzzy test, run several tries.
     for _ in 0..NTEST {
-        for i in 1..DATASZ + 1 {
+        for i in 1..=DATASZ {
             DROP_COUNTER.store(0, Ordering::SeqCst);
 
             let mut panic_ords: Vec<_> = data.iter()

src/liballoc/tests/btree/map.rs

@@ -302,7 +302,7 @@ fn test_range() {
     for i in 0..size {
         for j in i..size {
             let mut kvs = map.range((Included(&i), Included(&j))).map(|(&k, &v)| (k, v));
-            let mut pairs = (i..j + 1).map(|i| (i, i));
+            let mut pairs = (i..=j).map(|i| (i, i));
 
             for (kv, pair) in kvs.by_ref().zip(pairs.by_ref()) {
                 assert_eq!(kv, pair);
@@ -321,7 +321,7 @@ fn test_range_mut() {
     for i in 0..size {
         for j in i..size {
             let mut kvs = map.range_mut((Included(&i), Included(&j))).map(|(&k, &mut v)| (k, v));
-            let mut pairs = (i..j + 1).map(|i| (i, i));
+            let mut pairs = (i..=j).map(|i| (i, i));
 
             for (kv, pair) in kvs.by_ref().zip(pairs.by_ref()) {
                 assert_eq!(kv, pair);

src/liballoc/tests/str.rs

@@ -1378,7 +1378,7 @@ fn test_bool_from_str() {
 fn check_contains_all_substrings(s: &str) {
     assert!(s.contains(""));
     for i in 0..s.len() {
-        for j in i+1..s.len() + 1 {
+        for j in i+1..=s.len() {
             assert!(s.contains(&s[i..j]));
         }
     }

src/liballoc/tests/vec_deque.rs

@@ -861,15 +861,15 @@ fn test_as_slices() {
         ring.push_back(i);
 
         let (left, right) = ring.as_slices();
-        let expected: Vec<_> = (0..i + 1).collect();
+        let expected: Vec<_> = (0..=i).collect();
         assert_eq!(left, &expected[..]);
         assert_eq!(right, []);
     }
 
     for j in -last..0 {
         ring.push_front(j);
         let (left, right) = ring.as_slices();
-        let expected_left: Vec<_> = (-last..j + 1).rev().collect();
+        let expected_left: Vec<_> = (-last..=j).rev().collect();
         let expected_right: Vec<_> = (0..first).collect();
         assert_eq!(left, &expected_left[..]);
         assert_eq!(right, &expected_right[..]);
@@ -889,15 +889,15 @@ fn test_as_mut_slices() {
         ring.push_back(i);
 
         let (left, right) = ring.as_mut_slices();
-        let expected: Vec<_> = (0..i + 1).collect();
+        let expected: Vec<_> = (0..=i).collect();
         assert_eq!(left, &expected[..]);
         assert_eq!(right, []);
     }
 
     for j in -last..0 {
         ring.push_front(j);
         let (left, right) = ring.as_mut_slices();
-        let expected_left: Vec<_> = (-last..j + 1).rev().collect();
+        let expected_left: Vec<_> = (-last..=j).rev().collect();
         let expected_right: Vec<_> = (0..first).collect();
         assert_eq!(left, &expected_left[..]);
         assert_eq!(right, &expected_right[..]);

src/libcore/ptr.rs

@@ -2516,6 +2516,36 @@ pub fn eq<T: ?Sized>(a: *const T, b: *const T) -> bool {
     a == b
 }
 
+/// Hash the raw pointer address behind a reference, rather than the value
+/// it points to.
+///
+/// # Examples
+///
+/// ```
+/// #![feature(ptr_hash)]
+/// use std::collections::hash_map::DefaultHasher;
+/// use std::hash::{Hash, Hasher};
+/// use std::ptr;
+///
+/// let five = 5;
+/// let five_ref = &five;
+///
+/// let mut hasher = DefaultHasher::new();
+/// ptr::hash(five_ref, &mut hasher);
+/// let actual = hasher.finish();
+///
+/// let mut hasher = DefaultHasher::new();
+/// (five_ref as *const i32).hash(&mut hasher);
+/// let expected = hasher.finish();
+///
+/// assert_eq!(actual, expected);
+/// ```
+#[unstable(feature = "ptr_hash", reason = "newly added", issue = "56286")]
+pub fn hash<T, S: hash::Hasher>(hashee: *const T, into: &mut S) {
+    use hash::Hash;
+    hashee.hash(into);
+}
+
 // Impls for function pointers
 macro_rules! fnptr_impls_safety_abi {
     ($FnTy: ty, $($Arg: ident),*) => {

src/libcore/slice/mod.rs

@@ -702,8 +702,7 @@ impl<T> [T] {
     /// resulting code better than in the case of [`chunks`].
     ///
     /// See [`chunks`] for a variant of this iterator that also returns the remainder as a smaller
-    /// chunk, and [`rchunks_exact`] for the same iterator but starting at the end of the slice of
-    /// the slice.
+    /// chunk, and [`rchunks_exact`] for the same iterator but starting at the end of the slice.
     ///
     /// # Panics
     ///

src/librustc/hir/map/hir_id_validator.rs

@@ -100,7 +100,7 @@ impl<'a, 'hir: 'a> HirIdValidator<'a, 'hir> {
 
         if max != self.hir_ids_seen.len() - 1 {
             // Collect the missing ItemLocalIds
-            let missing: Vec<_> = (0 .. max as u32 + 1)
+            let missing: Vec<_> = (0 ..= max as u32)
               .filter(|&i| !self.hir_ids_seen.contains_key(&ItemLocalId::from_u32(i)))
               .collect();
 

src/librustc/mir/mod.rs

@@ -339,7 +339,7 @@ impl<'tcx> Mir<'tcx> {
     #[inline]
     pub fn args_iter(&self) -> impl Iterator<Item = Local> {
         let arg_count = self.arg_count;
-        (1..arg_count + 1).map(Local::new)
+        (1..=arg_count).map(Local::new)
     }
 
     /// Returns an iterator over all user-defined variables and compiler-generated temporaries (all

src/librustc/ty/context.rs

@@ -1942,8 +1942,12 @@ pub mod tls {
     /// This is a callback from libsyntax as it cannot access the implicit state
     /// in librustc otherwise
     fn span_debug(span: syntax_pos::Span, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        with(|tcx| {
-            write!(f, "{}", tcx.sess.source_map().span_to_string(span))
+        with_opt(|tcx| {
+            if let Some(tcx) = tcx {
+                write!(f, "{}", tcx.sess.source_map().span_to_string(span))
+            } else {
+                syntax_pos::default_span_debug(span, f)
+            }
         })
     }
 

src/librustc/ty/query/job.rs

@@ -103,8 +103,11 @@ impl<'tcx> QueryJob<'tcx> {
                     condvar: Condvar::new(),
                 });
                 self.latch.await(&waiter);
-
-                match Lrc::get_mut(&mut waiter).unwrap().cycle.get_mut().take() {
+                // FIXME: Get rid of this lock. We have ownership of the QueryWaiter
+                // although another thread may still have a Lrc reference so we cannot
+                // use Lrc::get_mut
+                let mut cycle = waiter.cycle.lock();
+                match cycle.take() {
                     None => Ok(()),
                     Some(cycle) => Err(cycle)
                 }
@@ -326,19 +329,17 @@ fn connected_to_root<'tcx>(
     query: Lrc<QueryJob<'tcx>>,
     visited: &mut FxHashSet<*const QueryJob<'tcx>>
 ) -> bool {
-    // This query is connected to the root (it has no query parent), return true
-    if query.parent.is_none() {
-        return true;
-    }
-
     // We already visited this or we're deliberately ignoring it
     if visited.contains(&query.as_ptr()) {
         return false;
     }
 
-    visited.insert(query.as_ptr());
+    // This query is connected to the root (it has no query parent), return true
+    if query.parent.is_none() {
+        return true;
+    }
 
-    let mut connected = false;
+    visited.insert(query.as_ptr());
 
     visit_waiters(query, |_, successor| {
         if connected_to_root(successor, visited) {
@@ -349,6 +350,28 @@ fn connected_to_root<'tcx>(
     }).is_some()
 }
 
+// Deterministically pick an query from a list
+#[cfg(parallel_queries)]
+fn pick_query<'a, 'tcx, T, F: Fn(&T) -> (Span, Lrc<QueryJob<'tcx>>)>(
+    tcx: TyCtxt<'_, 'tcx, '_>,
+    queries: &'a [T],
+    f: F
+) -> &'a T {
+    // Deterministically pick an entry point
+    // FIXME: Sort this instead
+    let mut hcx = tcx.create_stable_hashing_context();
+    queries.iter().min_by_key(|v| {
+        let (span, query) = f(v);
+        let mut stable_hasher = StableHasher::<u64>::new();
+        query.info.query.hash_stable(&mut hcx, &mut stable_hasher);
+        // Prefer entry points which have valid spans for nicer error messages
+        // We add an integer to the tuple ensuring that entry points
+        // with valid spans are picked first
+        let span_cmp = if span == DUMMY_SP { 1 } else { 0 };
+        (span_cmp, stable_hasher.finish())
+    }).unwrap()
+}
+
 /// Looks for query cycles starting from the last query in `jobs`.
 /// If a cycle is found, all queries in the cycle is removed from `jobs` and
 /// the function return true.
@@ -388,41 +411,52 @@ fn remove_cycle<'tcx>(
 
         // Find the queries in the cycle which are
         // connected to queries outside the cycle
-        let entry_points = stack.iter().filter_map(|query| {
-            // Mark all the other queries in the cycle as already visited
-            let mut visited = FxHashSet::from_iter(stack.iter().filter_map(|q| {
-                if q.1.as_ptr() != query.1.as_ptr() {
-                    Some(q.1.as_ptr())
-                } else {
+        let entry_points: Vec<_> = stack.iter().filter_map(|(span, query)| {
+            if query.parent.is_none() {
+                // This query is connected to the root (it has no query parent)
+                Some((*span, query.clone(), None))
+            } else {
+                let mut waiters = Vec::new();
+                // Find all the direct waiters who lead to the root
+                visit_waiters(query.clone(), |span, waiter| {
+                    // Mark all the other queries in the cycle as already visited
+                    let mut visited = FxHashSet::from_iter(stack.iter().map(|q| q.1.as_ptr()));
+
+                    if connected_to_root(waiter.clone(), &mut visited) {
+                        waiters.push((span, waiter));
+                    }
+
+                    None
+                });
+                if waiters.is_empty() {
                     None
+                } else {
+                    // Deterministically pick one of the waiters to show to the user
+                    let waiter = pick_query(tcx, &waiters, |s| s.clone()).clone();
+                    Some((*span, query.clone(), Some(waiter)))
                 }
-            }));
-
-            if connected_to_root(query.1.clone(), &mut visited) {
-                Some(query.1.clone())
-            } else {
-                None
             }
-        });
+        }).collect();
+
+        let entry_points: Vec<(Span, Lrc<QueryJob<'tcx>>, Option<(Span, Lrc<QueryJob<'tcx>>)>)>
+         = entry_points;
 
         // Deterministically pick an entry point
-        // FIXME: Sort this instead
-        let mut hcx = tcx.create_stable_hashing_context();
-        let entry_point = entry_points.min_by_key(|q| {
-            let mut stable_hasher = StableHasher::<u64>::new();
-            q.info.query.hash_stable(&mut hcx, &mut stable_hasher);
-            stable_hasher.finish()
-        }).unwrap().as_ptr();
+        let (_, entry_point, usage) = pick_query(tcx, &entry_points, |e| (e.0, e.1.clone()));
 
         // Shift the stack so that our entry point is first
-        let entry_point_pos = stack.iter().position(|(_, query)| query.as_ptr() == entry_point);
+        let entry_point_pos = stack.iter().position(|(_, query)| {
+            query.as_ptr() == entry_point.as_ptr()
+        });
         if let Some(pos) = entry_point_pos {
-            stack.rotate_right(pos);
+            stack.rotate_left(pos);
         }
 
+        let usage = usage.as_ref().map(|(span, query)| (*span, query.info.query.clone()));
+
         // Create the cycle error
         let mut error = CycleError {
-            usage: None,
+            usage,
             cycle: stack.iter().map(|&(s, ref q)| QueryInfo {
                 span: s,
                 query: q.info.query.clone(),

src/librustc/util/profiling.rs

@@ -11,7 +11,7 @@
 use session::config::Options;
 
 use std::fs;
-use std::io::{self, StdoutLock, Write};
+use std::io::{self, StderrLock, Write};
 use std::time::{Duration, Instant};
 
 macro_rules! define_categories {
@@ -61,7 +61,7 @@ macro_rules! define_categories {
                 }
             }
 
-            fn print(&self, lock: &mut StdoutLock<'_>) {
+            fn print(&self, lock: &mut StderrLock<'_>) {
                 writeln!(lock, "| Phase            | Time (ms)      | Queries        | Hits (%) |")
                     .unwrap();
                 writeln!(lock, "| ---------------- | -------------- | -------------- | -------- |")
@@ -235,7 +235,7 @@ impl SelfProfiler {
             self.timer_stack.is_empty(),
             "there were timers running when print_results() was called");
 
-        let out = io::stdout();
+        let out = io::stderr();
         let mut lock = out.lock();
 
         let crate_name =