Rollup of 5 pull requests

src/liballoc/rc.rs

@@ -1515,18 +1515,18 @@ impl<T: ?Sized> Weak<T> {
     ///
     /// ```
     /// #![feature(weak_ptr_eq)]
-    /// use std::rc::{Rc, Weak};
+    /// use std::rc::Rc;
     ///
     /// let first_rc = Rc::new(5);
     /// let first = Rc::downgrade(&first_rc);
     /// let second = Rc::downgrade(&first_rc);
     ///
-    /// assert!(Weak::ptr_eq(&first, &second));
+    /// assert!(first.ptr_eq(&second));
     ///
     /// let third_rc = Rc::new(5);
     /// let third = Rc::downgrade(&third_rc);
     ///
-    /// assert!(!Weak::ptr_eq(&first, &third));
+    /// assert!(!first.ptr_eq(&third));
     /// ```
     ///
     /// Comparing `Weak::new`.
@@ -1537,16 +1537,16 @@ impl<T: ?Sized> Weak<T> {
     ///
     /// let first = Weak::new();
     /// let second = Weak::new();
-    /// assert!(Weak::ptr_eq(&first, &second));
+    /// assert!(first.ptr_eq(&second));
     ///
     /// let third_rc = Rc::new(());
     /// let third = Rc::downgrade(&third_rc);
-    /// assert!(!Weak::ptr_eq(&first, &third));
+    /// assert!(!first.ptr_eq(&third));
     /// ```
     #[inline]
     #[unstable(feature = "weak_ptr_eq", issue = "55981")]
-    pub fn ptr_eq(this: &Self, other: &Self) -> bool {
-        this.ptr.as_ptr() == other.ptr.as_ptr()
+    pub fn ptr_eq(&self, other: &Self) -> bool {
+        self.ptr.as_ptr() == other.ptr.as_ptr()
     }
 }
 

src/liballoc/sync.rs

@@ -1349,18 +1349,18 @@ impl<T: ?Sized> Weak<T> {
     ///
     /// ```
     /// #![feature(weak_ptr_eq)]
-    /// use std::sync::{Arc, Weak};
+    /// use std::sync::Arc;
     ///
     /// let first_rc = Arc::new(5);
     /// let first = Arc::downgrade(&first_rc);
     /// let second = Arc::downgrade(&first_rc);
     ///
-    /// assert!(Weak::ptr_eq(&first, &second));
+    /// assert!(first.ptr_eq(&second));
     ///
     /// let third_rc = Arc::new(5);
     /// let third = Arc::downgrade(&third_rc);
     ///
-    /// assert!(!Weak::ptr_eq(&first, &third));
+    /// assert!(!first.ptr_eq(&third));
     /// ```
     ///
     /// Comparing `Weak::new`.
@@ -1371,16 +1371,16 @@ impl<T: ?Sized> Weak<T> {
     ///
     /// let first = Weak::new();
     /// let second = Weak::new();
-    /// assert!(Weak::ptr_eq(&first, &second));
+    /// assert!(first.ptr_eq(&second));
     ///
     /// let third_rc = Arc::new(());
     /// let third = Arc::downgrade(&third_rc);
-    /// assert!(!Weak::ptr_eq(&first, &third));
+    /// assert!(!first.ptr_eq(&third));
     /// ```
     #[inline]
     #[unstable(feature = "weak_ptr_eq", issue = "55981")]
-    pub fn ptr_eq(this: &Self, other: &Self) -> bool {
-        this.ptr.as_ptr() == other.ptr.as_ptr()
+    pub fn ptr_eq(&self, other: &Self) -> bool {
+        self.ptr.as_ptr() == other.ptr.as_ptr()
     }
 }
 

src/libcore/intrinsics.rs

@@ -1607,3 +1607,9 @@ pub fn maxnumf64(x: f64, y: f64) -> f64 {
     // Identical to the `f32` case.
     (if x < y || x != x { y } else { x }) * 1.0
 }
+
+/// For bootstrapping, implement unchecked_sub as just wrapping_sub.
+#[cfg(bootstrap)]
+pub unsafe fn unchecked_sub<T>(x: T, y: T) -> T {
+    sub_with_overflow(x, y).0
+}

src/libcore/slice/mod.rs

@@ -25,7 +25,7 @@
 use crate::cmp::Ordering::{self, Less, Equal, Greater};
 use crate::cmp;
 use crate::fmt;
-use crate::intrinsics::assume;
+use crate::intrinsics::{assume, exact_div, unchecked_sub};
 use crate::isize;
 use crate::iter::*;
 use crate::ops::{FnMut, Try, self};
@@ -2998,14 +2998,27 @@ macro_rules! is_empty {
 // unexpected way. (Tested by `codegen/slice-position-bounds-check`.)
 macro_rules! len {
     ($self: ident) => {{
+        #![allow(unused_unsafe)] // we're sometimes used within an unsafe block
+
         let start = $self.ptr;
-        let diff = ($self.end as usize).wrapping_sub(start as usize);
         let size = size_from_ptr(start);
         if size == 0 {
+            // This _cannot_ use `unchecked_sub` because we depend on wrapping
+            // to represent the length of long ZST slice iterators.
+            let diff = ($self.end as usize).wrapping_sub(start as usize);
             diff
         } else {
-            // Using division instead of `offset_from` helps LLVM remove bounds checks
-            diff / size
+            // We know that `start <= end`, so can do better than `offset_from`,
+            // which needs to deal in signed.  By setting appropriate flags here
+            // we can tell LLVM this, which helps it remove bounds checks.
+            // SAFETY: By the type invariant, `start <= end`
+            let diff = unsafe { unchecked_sub($self.end as usize, start as usize) };
+            // By also telling LLVM that the pointers are apart by an exact
+            // multiple of the type size, it can optimize `len() == 0` down to
+            // `start == end` instead of `(end - start) < size`.
+            // SAFETY: By the type invariant, the pointers are aligned so the
+            //         distance between them must be a multiple of pointee size
+            unsafe { exact_div(diff, size) }
         }
     }}
 }

src/librustc/cfg/construct.rs

@@ -42,7 +42,7 @@ pub fn construct<'tcx>(tcx: TyCtxt<'tcx>, body: &hir::Body) -> CFG {
     let body_exit;
 
     // Find the tables for this body.
-    let owner_def_id = tcx.hir().local_def_id(tcx.hir().body_owner(body.id()));
+    let owner_def_id = tcx.hir().body_owner_def_id(body.id());
     let tables = tcx.typeck_tables_of(owner_def_id);
 
     let mut cfg_builder = CFGBuilder {
@@ -357,7 +357,7 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
             args: I) -> CFGIndex {
         let func_or_rcvr_exit = self.expr(func_or_rcvr, pred);
         let ret = self.straightline(call_expr, func_or_rcvr_exit, args);
-        let m = self.tcx.hir().get_module_parent_by_hir_id(call_expr.hir_id);
+        let m = self.tcx.hir().get_module_parent(call_expr.hir_id);
         if self.tcx.is_ty_uninhabited_from(m, self.tables.expr_ty(call_expr)) {
             self.add_unreachable_node()
         } else {

src/librustc/cfg/graphviz.rs

@@ -22,11 +22,11 @@ pub struct LabelledCFG<'a, 'tcx: 'a> {
 impl<'a, 'tcx> LabelledCFG<'a, 'tcx> {
     fn local_id_to_string(&self, local_id: hir::ItemLocalId) -> String {
         assert!(self.cfg.owner_def_id.is_local());
-        let node_id = self.tcx.hir().hir_to_node_id(hir::HirId {
+        let hir_id = hir::HirId {
             owner: self.tcx.hir().def_index_to_hir_id(self.cfg.owner_def_id.index).owner,
             local_id
-        });
-        let s = self.tcx.hir().node_to_string(node_id);
+        };
+        let s = self.tcx.hir().node_to_string(hir_id);
 
         // Replacing newlines with \\l causes each line to be left-aligned,
         // improving presentation of (long) pretty-printed expressions.

src/librustc/hir/intravisit.rs

@@ -171,7 +171,7 @@ pub trait Visitor<'v> : Sized {
     /// but cannot supply a `Map`; see `nested_visit_map` for advice.
     #[allow(unused_variables)]
     fn visit_nested_item(&mut self, id: ItemId) {
-        let opt_item = self.nested_visit_map().inter().map(|map| map.expect_item_by_hir_id(id.id));
+        let opt_item = self.nested_visit_map().inter().map(|map| map.expect_item(id.id));
         if let Some(item) = opt_item {
             self.visit_item(item);
         }

src/librustc/hir/map/hir_id_validator.rs

@@ -1,6 +1,5 @@
 use crate::hir::def_id::{DefId, DefIndex, CRATE_DEF_INDEX};
 use crate::hir::{self, intravisit, HirId, ItemLocalId};
-use syntax::ast::NodeId;
 use crate::hir::itemlikevisit::ItemLikeVisitor;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::sync::{Lock, ParallelIterator, par_iter};
@@ -112,19 +111,9 @@ impl<'a, 'hir: 'a> HirIdValidator<'a, 'hir> {
 
                 trace!("missing hir id {:#?}", hir_id);
 
-                // We are already in ICE mode here, so doing a linear search
-                // should be fine.
-                let (node_id, _) = self.hir_map
-                                       .definitions()
-                                       .node_to_hir_id
-                                       .iter()
-                                       .enumerate()
-                                       .find(|&(_, &entry)| hir_id == entry)
-                                       .expect("no node_to_hir_id entry");
-                let node_id = NodeId::from_usize(node_id);
                 missing_items.push(format!("[local_id: {}, node:{}]",
                                            local_id,
-                                           self.hir_map.node_to_string(node_id)));
+                                           self.hir_map.node_to_string(hir_id)));
             }
             self.error(|| format!(
                 "ItemLocalIds not assigned densely in {}. \
@@ -138,7 +127,7 @@ impl<'a, 'hir: 'a> HirIdValidator<'a, 'hir> {
                         owner: owner_def_index,
                         local_id,
                     })
-                    .map(|h| format!("({:?} {})", h, self.hir_map.hir_to_string(h)))
+                    .map(|h| format!("({:?} {})", h, self.hir_map.node_to_string(h)))
                     .collect::<Vec<_>>()));
         }
     }
@@ -156,14 +145,14 @@ impl<'a, 'hir: 'a> intravisit::Visitor<'hir> for HirIdValidator<'a, 'hir> {
 
         if hir_id == hir::DUMMY_HIR_ID {
             self.error(|| format!("HirIdValidator: HirId {:?} is invalid",
-                                  self.hir_map.hir_to_string(hir_id)));
+                                  self.hir_map.node_to_string(hir_id)));
             return;
         }
 
         if owner != hir_id.owner {
             self.error(|| format!(
                 "HirIdValidator: The recorded owner of {} is {} instead of {}",
-                self.hir_map.hir_to_string(hir_id),
+                self.hir_map.node_to_string(hir_id),
                 self.hir_map.def_path(DefId::local(hir_id.owner)).to_string_no_crate(),
                 self.hir_map.def_path(DefId::local(owner)).to_string_no_crate()));
         }