From c7de289e1c8d24bd55aaa33813e509920a00c364 Mon Sep 17 00:00:00 2001
From: Aria Beingessner <a.beingessner@gmail.com>
Date: Tue, 22 Mar 2022 01:24:55 -0400
Subject: Make the stdlib largely conform to strict provenance.

Some things like the unwinders and system APIs are not fully conformant,
this only covers a lot of low-hanging fruit.
---
 library/alloc/src/lib.rs           | 1 +
 library/alloc/src/rc.rs            | 5 ++---
 library/alloc/src/slice.rs         | 2 +-
 library/alloc/src/sync.rs          | 2 +-
 library/alloc/src/vec/into_iter.rs | 2 +-
 5 files changed, 6 insertions(+), 6 deletions(-)

(limited to 'library/alloc/src')

diff --git a/library/alloc/src/lib.rs b/library/alloc/src/lib.rs
index 0a180b83355..7e90d77b8f2 100644
--- a/library/alloc/src/lib.rs
+++ b/library/alloc/src/lib.rs
@@ -158,6 +158,7 @@
 #![feature(rustc_allow_const_fn_unstable)]
 #![feature(rustc_attrs)]
 #![feature(staged_api)]
+#![feature(strict_provenance)]
 #![cfg_attr(test, feature(test))]
 #![feature(unboxed_closures)]
 #![feature(unsized_fn_params)]
diff --git a/library/alloc/src/rc.rs b/library/alloc/src/rc.rs
index 3ddc9acb2e7..0b57c36247e 100644
--- a/library/alloc/src/rc.rs
+++ b/library/alloc/src/rc.rs
@@ -2115,13 +2115,12 @@ impl<T> Weak<T> {
     #[rustc_const_unstable(feature = "const_weak_new", issue = "95091", reason = "recently added")]
     #[must_use]
     pub const fn new() -> Weak<T> {
-        Weak { ptr: unsafe { NonNull::new_unchecked(usize::MAX as *mut RcBox<T>) } }
+        Weak { ptr: unsafe { NonNull::new_unchecked(ptr::invalid_mut::<RcBox<T>>(usize::MAX)) } }
     }
 }
 
 pub(crate) fn is_dangling<T: ?Sized>(ptr: *mut T) -> bool {
-    let address = ptr as *mut () as usize;
-    address == usize::MAX
+    (ptr as *mut ()).addr() == usize::MAX
 }
 
 /// Helper type to allow accessing the reference counts without
diff --git a/library/alloc/src/slice.rs b/library/alloc/src/slice.rs
index f52871c73d9..7c892f03bfb 100644
--- a/library/alloc/src/slice.rs
+++ b/library/alloc/src/slice.rs
@@ -1044,7 +1044,7 @@ where
     impl<T> Drop for MergeHole<T> {
         fn drop(&mut self) {
             // `T` is not a zero-sized type, so it's okay to divide by its size.
-            let len = (self.end as usize - self.start as usize) / mem::size_of::<T>();
+            let len = (self.end.addr() - self.start.addr()) / mem::size_of::<T>();
             unsafe {
                 ptr::copy_nonoverlapping(self.start, self.dest, len);
             }
diff --git a/library/alloc/src/sync.rs b/library/alloc/src/sync.rs
index e2b9890850b..f8b4d46ac10 100644
--- a/library/alloc/src/sync.rs
+++ b/library/alloc/src/sync.rs
@@ -1746,7 +1746,7 @@ impl<T> Weak<T> {
     #[rustc_const_unstable(feature = "const_weak_new", issue = "95091", reason = "recently added")]
     #[must_use]
     pub const fn new() -> Weak<T> {
-        Weak { ptr: unsafe { NonNull::new_unchecked(usize::MAX as *mut ArcInner<T>) } }
+        Weak { ptr: unsafe { NonNull::new_unchecked(ptr::invalid_mut::<ArcInner<T>>(usize::MAX)) } }
     }
 }
 
diff --git a/library/alloc/src/vec/into_iter.rs b/library/alloc/src/vec/into_iter.rs
index f17b8d71b3a..cc6dfb0e330 100644
--- a/library/alloc/src/vec/into_iter.rs
+++ b/library/alloc/src/vec/into_iter.rs
@@ -159,7 +159,7 @@ impl<T, A: Allocator> Iterator for IntoIter<T, A> {
     #[inline]
     fn size_hint(&self) -> (usize, Option<usize>) {
         let exact = if mem::size_of::<T>() == 0 {
-            (self.end as usize).wrapping_sub(self.ptr as usize)
+            self.end.addr().wrapping_sub(self.ptr.addr())
         } else {
             unsafe { self.end.offset_from(self.ptr) as usize }
         };
-- 
cgit 1.4.1-3-g733a5