Auto merge of #61274 - Centril:rollup-23dekk4, r=Centril

Rollup of 4 pull requests

Successful merges:

 - #61123 (Allow to specify profiling data output directory as -Zself-profile argument.)
 - #61159 (split core::ptr module into multiple files)
 - #61164 (rename Scalar::Bits to Scalar::Raw and bits field to data)
 - #61250 (Remove special case for *ios* builds in run-make-fulldeps/print-target-list Makefile)

Failed merges:

r? @ghost

29 files changed, 645 insertions, 618 deletions

diff --git a/src/libcore/ptr.rs b/src/libcore/ptr/mod.rs
index 4bb4d3ee466..80ac67d8eb5 100644
--- a/src/libcore/ptr.rs
+++ b/src/libcore/ptr/mod.rs
@@ -1,5 +1,3 @@
-// ignore-tidy-filelength
-
 //! Manually manage memory through raw pointers.
 //!
 //! *[See also the pointer primitive types](../../std/primitive.pointer.html).*
@@ -65,14 +63,10 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use crate::convert::From;
 use crate::intrinsics;
-use crate::ops::{CoerceUnsized, DispatchFromDyn};
 use crate::fmt;
 use crate::hash;
-use crate::marker::{PhantomData, Unsize};
 use crate::mem::{self, MaybeUninit};
-
 use crate::cmp::Ordering::{self, Less, Equal, Greater};
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -84,6 +78,14 @@ pub use crate::intrinsics::copy;
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use crate::intrinsics::write_bytes;
 
+mod non_null;
+#[stable(feature = "nonnull", since = "1.25.0")]
+pub use non_null::NonNull;
+
+mod unique;
+#[unstable(feature = "ptr_internals", issue = "0")]
+pub use unique::Unique;
+
 /// Executes the destructor (if any) of the pointed-to value.
 ///
 /// This is semantically equivalent to calling [`ptr::read`] and discarding
@@ -2742,384 +2744,3 @@ impl<T: ?Sized> PartialOrd for *mut T {
     #[inline]
     fn ge(&self, other: &*mut T) -> bool { *self >= *other }
 }
-
-/// A wrapper around a raw non-null `*mut T` that indicates that the possessor
-/// of this wrapper owns the referent. Useful for building abstractions like
-/// `Box<T>`, `Vec<T>`, `String`, and `HashMap<K, V>`.
-///
-/// Unlike `*mut T`, `Unique<T>` behaves "as if" it were an instance of `T`.
-/// It implements `Send`/`Sync` if `T` is `Send`/`Sync`. It also implies
-/// the kind of strong aliasing guarantees an instance of `T` can expect:
-/// the referent of the pointer should not be modified without a unique path to
-/// its owning Unique.
-///
-/// If you're uncertain of whether it's correct to use `Unique` for your purposes,
-/// consider using `NonNull`, which has weaker semantics.
-///
-/// Unlike `*mut T`, the pointer must always be non-null, even if the pointer
-/// is never dereferenced. This is so that enums may use this forbidden value
-/// as a discriminant -- `Option<Unique<T>>` has the same size as `Unique<T>`.
-/// However the pointer may still dangle if it isn't dereferenced.
-///
-/// Unlike `*mut T`, `Unique<T>` is covariant over `T`. This should always be correct
-/// for any type which upholds Unique's aliasing requirements.
-#[unstable(feature = "ptr_internals", issue = "0",
-           reason = "use NonNull instead and consider PhantomData<T> \
-                     (if you also use #[may_dangle]), Send, and/or Sync")]
-#[doc(hidden)]
-#[repr(transparent)]
-#[rustc_layout_scalar_valid_range_start(1)]
-pub struct Unique<T: ?Sized> {
-    pointer: *const T,
-    // NOTE: this marker has no consequences for variance, but is necessary
-    // for dropck to understand that we logically own a `T`.
-    //
-    // For details, see:
-    // https://github.com/rust-lang/rfcs/blob/master/text/0769-sound-generic-drop.md#phantom-data
-    _marker: PhantomData<T>,
-}
-
-#[unstable(feature = "ptr_internals", issue = "0")]
-impl<T: ?Sized> fmt::Debug for Unique<T> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Pointer::fmt(&self.as_ptr(), f)
-    }
-}
-
-/// `Unique` pointers are `Send` if `T` is `Send` because the data they
-/// reference is unaliased. Note that this aliasing invariant is
-/// unenforced by the type system; the abstraction using the
-/// `Unique` must enforce it.
-#[unstable(feature = "ptr_internals", issue = "0")]
-unsafe impl<T: Send + ?Sized> Send for Unique<T> { }
-
-/// `Unique` pointers are `Sync` if `T` is `Sync` because the data they
-/// reference is unaliased. Note that this aliasing invariant is
-/// unenforced by the type system; the abstraction using the
-/// `Unique` must enforce it.
-#[unstable(feature = "ptr_internals", issue = "0")]
-unsafe impl<T: Sync + ?Sized> Sync for Unique<T> { }
-
-#[unstable(feature = "ptr_internals", issue = "0")]
-impl<T: Sized> Unique<T> {
-    /// Creates a new `Unique` that is dangling, but well-aligned.
-    ///
-    /// This is useful for initializing types which lazily allocate, like
-    /// `Vec::new` does.
-    ///
-    /// Note that the pointer value may potentially represent a valid pointer to
-    /// a `T`, which means this must not be used as a "not yet initialized"
-    /// sentinel value. Types that lazily allocate must track initialization by
-    /// some other means.
-    // FIXME: rename to dangling() to match NonNull?
-    pub const fn empty() -> Self {
-        unsafe {
-            Unique::new_unchecked(mem::align_of::<T>() as *mut T)
-        }
-    }
-}
-
-#[unstable(feature = "ptr_internals", issue = "0")]
-impl<T: ?Sized> Unique<T> {
-    /// Creates a new `Unique`.
-    ///
-    /// # Safety
-    ///
-    /// `ptr` must be non-null.
-    pub const unsafe fn new_unchecked(ptr: *mut T) -> Self {
-        Unique { pointer: ptr as _, _marker: PhantomData }
-    }
-
-    /// Creates a new `Unique` if `ptr` is non-null.
-    pub fn new(ptr: *mut T) -> Option<Self> {
-        if !ptr.is_null() {
-            Some(unsafe { Unique { pointer: ptr as _, _marker: PhantomData } })
-        } else {
-            None
-        }
-    }
-
-    /// Acquires the underlying `*mut` pointer.
-    pub const fn as_ptr(self) -> *mut T {
-        self.pointer as *mut T
-    }
-
-    /// Dereferences the content.
-    ///
-    /// The resulting lifetime is bound to self so this behaves "as if"
-    /// it were actually an instance of T that is getting borrowed. If a longer
-    /// (unbound) lifetime is needed, use `&*my_ptr.as_ptr()`.
-    pub unsafe fn as_ref(&self) -> &T {
-        &*self.as_ptr()
-    }
-
-    /// Mutably dereferences the content.
-    ///
-    /// The resulting lifetime is bound to self so this behaves "as if"
-    /// it were actually an instance of T that is getting borrowed. If a longer
-    /// (unbound) lifetime is needed, use `&mut *my_ptr.as_ptr()`.
-    pub unsafe fn as_mut(&mut self) -> &mut T {
-        &mut *self.as_ptr()
-    }
-}
-
-#[unstable(feature = "ptr_internals", issue = "0")]
-impl<T: ?Sized> Clone for Unique<T> {
-    fn clone(&self) -> Self {
-        *self
-    }
-}
-
-#[unstable(feature = "ptr_internals", issue = "0")]
-impl<T: ?Sized> Copy for Unique<T> { }
-
-#[unstable(feature = "ptr_internals", issue = "0")]
-impl<T: ?Sized, U: ?Sized> CoerceUnsized<Unique<U>> for Unique<T> where T: Unsize<U> { }
-
-#[unstable(feature = "ptr_internals", issue = "0")]
-impl<T: ?Sized, U: ?Sized> DispatchFromDyn<Unique<U>> for Unique<T> where T: Unsize<U> { }
-
-#[unstable(feature = "ptr_internals", issue = "0")]
-impl<T: ?Sized> fmt::Pointer for Unique<T> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Pointer::fmt(&self.as_ptr(), f)
-    }
-}
-
-#[unstable(feature = "ptr_internals", issue = "0")]
-impl<T: ?Sized> From<&mut T> for Unique<T> {
-    fn from(reference: &mut T) -> Self {
-        unsafe { Unique { pointer: reference as *mut T, _marker: PhantomData } }
-    }
-}
-
-#[unstable(feature = "ptr_internals", issue = "0")]
-impl<T: ?Sized> From<&T> for Unique<T> {
-    fn from(reference: &T) -> Self {
-        unsafe { Unique { pointer: reference as *const T, _marker: PhantomData } }
-    }
-}
-
-#[unstable(feature = "ptr_internals", issue = "0")]
-impl<'a, T: ?Sized> From<NonNull<T>> for Unique<T> {
-    fn from(p: NonNull<T>) -> Self {
-        unsafe { Unique { pointer: p.pointer, _marker: PhantomData } }
-    }
-}
-
-/// `*mut T` but non-zero and covariant.
-///
-/// This is often the correct thing to use when building data structures using
-/// raw pointers, but is ultimately more dangerous to use because of its additional
-/// properties. If you're not sure if you should use `NonNull<T>`, just use `*mut T`!
-///
-/// Unlike `*mut T`, the pointer must always be non-null, even if the pointer
-/// is never dereferenced. This is so that enums may use this forbidden value
-/// as a discriminant -- `Option<NonNull<T>>` has the same size as `*mut T`.
-/// However the pointer may still dangle if it isn't dereferenced.
-///
-/// Unlike `*mut T`, `NonNull<T>` is covariant over `T`. If this is incorrect
-/// for your use case, you should include some [`PhantomData`] in your type to
-/// provide invariance, such as `PhantomData<Cell<T>>` or `PhantomData<&'a mut T>`.
-/// Usually this won't be necessary; covariance is correct for most safe abstractions,
-/// such as `Box`, `Rc`, `Arc`, `Vec`, and `LinkedList`. This is the case because they
-/// provide a public API that follows the normal shared XOR mutable rules of Rust.
-///
-/// Notice that `NonNull<T>` has a `From` instance for `&T`. However, this does
-/// not change the fact that mutating through a (pointer derived from a) shared
-/// reference is undefined behavior unless the mutation happens inside an
-/// [`UnsafeCell<T>`]. The same goes for creating a mutable reference from a shared
-/// reference. When using this `From` instance without an `UnsafeCell<T>`,
-/// it is your responsibility to ensure that `as_mut` is never called, and `as_ptr`
-/// is never used for mutation.
-///
-/// [`PhantomData`]: ../marker/struct.PhantomData.html
-/// [`UnsafeCell<T>`]: ../cell/struct.UnsafeCell.html
-#[stable(feature = "nonnull", since = "1.25.0")]
-#[repr(transparent)]
-#[rustc_layout_scalar_valid_range_start(1)]
-#[cfg_attr(not(stage0), rustc_nonnull_optimization_guaranteed)]
-pub struct NonNull<T: ?Sized> {
-    pointer: *const T,
-}
-
-/// `NonNull` pointers are not `Send` because the data they reference may be aliased.
-// N.B., this impl is unnecessary, but should provide better error messages.
-#[stable(feature = "nonnull", since = "1.25.0")]
-impl<T: ?Sized> !Send for NonNull<T> { }
-
-/// `NonNull` pointers are not `Sync` because the data they reference may be aliased.
-// N.B., this impl is unnecessary, but should provide better error messages.
-#[stable(feature = "nonnull", since = "1.25.0")]
-impl<T: ?Sized> !Sync for NonNull<T> { }
-
-impl<T: Sized> NonNull<T> {
-    /// Creates a new `NonNull` that is dangling, but well-aligned.
-    ///
-    /// This is useful for initializing types which lazily allocate, like
-    /// `Vec::new` does.
-    ///
-    /// Note that the pointer value may potentially represent a valid pointer to
-    /// a `T`, which means this must not be used as a "not yet initialized"
-    /// sentinel value. Types that lazily allocate must track initialization by
-    /// some other means.
-    #[stable(feature = "nonnull", since = "1.25.0")]
-    #[inline]
-    pub const fn dangling() -> Self {
-        unsafe {
-            let ptr = mem::align_of::<T>() as *mut T;
-            NonNull::new_unchecked(ptr)
-        }
-    }
-}
-
-impl<T: ?Sized> NonNull<T> {
-    /// Creates a new `NonNull`.
-    ///
-    /// # Safety
-    ///
-    /// `ptr` must be non-null.
-    #[stable(feature = "nonnull", since = "1.25.0")]
-    #[inline]
-    pub const unsafe fn new_unchecked(ptr: *mut T) -> Self {
-        NonNull { pointer: ptr as _ }
-    }
-
-    /// Creates a new `NonNull` if `ptr` is non-null.
-    #[stable(feature = "nonnull", since = "1.25.0")]
-    #[inline]
-    pub fn new(ptr: *mut T) -> Option<Self> {
-        if !ptr.is_null() {
-            Some(unsafe { Self::new_unchecked(ptr) })
-        } else {
-            None
-        }
-    }
-
-    /// Acquires the underlying `*mut` pointer.
-    #[stable(feature = "nonnull", since = "1.25.0")]
-    #[inline]
-    pub const fn as_ptr(self) -> *mut T {
-        self.pointer as *mut T
-    }
-
-    /// Dereferences the content.
-    ///
-    /// The resulting lifetime is bound to self so this behaves "as if"
-    /// it were actually an instance of T that is getting borrowed. If a longer
-    /// (unbound) lifetime is needed, use `&*my_ptr.as_ptr()`.
-    #[stable(feature = "nonnull", since = "1.25.0")]
-    #[inline]
-    pub unsafe fn as_ref(&self) -> &T {
-        &*self.as_ptr()
-    }
-
-    /// Mutably dereferences the content.
-    ///
-    /// The resulting lifetime is bound to self so this behaves "as if"
-    /// it were actually an instance of T that is getting borrowed. If a longer
-    /// (unbound) lifetime is needed, use `&mut *my_ptr.as_ptr()`.
-    #[stable(feature = "nonnull", since = "1.25.0")]
-    #[inline]
-    pub unsafe fn as_mut(&mut self) -> &mut T {
-        &mut *self.as_ptr()
-    }
-
-    /// Cast to a pointer of another type
-    #[stable(feature = "nonnull_cast", since = "1.27.0")]
-    #[inline]
-    pub const fn cast<U>(self) -> NonNull<U> {
-        unsafe {
-            NonNull::new_unchecked(self.as_ptr() as *mut U)
-        }
-    }
-}
-
-#[stable(feature = "nonnull", since = "1.25.0")]
-impl<T: ?Sized> Clone for NonNull<T> {
-    fn clone(&self) -> Self {
-        *self
-    }
-}
-
-#[stable(feature = "nonnull", since = "1.25.0")]
-impl<T: ?Sized> Copy for NonNull<T> { }
-
-#[unstable(feature = "coerce_unsized", issue = "27732")]
-impl<T: ?Sized, U: ?Sized> CoerceUnsized<NonNull<U>> for NonNull<T> where T: Unsize<U> { }
-
-#[unstable(feature = "dispatch_from_dyn", issue = "0")]
-impl<T: ?Sized, U: ?Sized> DispatchFromDyn<NonNull<U>> for NonNull<T> where T: Unsize<U> { }
-
-#[stable(feature = "nonnull", since = "1.25.0")]
-impl<T: ?Sized> fmt::Debug for NonNull<T> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Pointer::fmt(&self.as_ptr(), f)
-    }
-}
-
-#[stable(feature = "nonnull", since = "1.25.0")]
-impl<T: ?Sized> fmt::Pointer for NonNull<T> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Pointer::fmt(&self.as_ptr(), f)
-    }
-}
-
-#[stable(feature = "nonnull", since = "1.25.0")]
-impl<T: ?Sized> Eq for NonNull<T> {}
-
-#[stable(feature = "nonnull", since = "1.25.0")]
-impl<T: ?Sized> PartialEq for NonNull<T> {
-    #[inline]
-    fn eq(&self, other: &Self) -> bool {
-        self.as_ptr() == other.as_ptr()
-    }
-}
-
-#[stable(feature = "nonnull", since = "1.25.0")]
-impl<T: ?Sized> Ord for NonNull<T> {
-    #[inline]
-    fn cmp(&self, other: &Self) -> Ordering {
-        self.as_ptr().cmp(&other.as_ptr())
-    }
-}
-
-#[stable(feature = "nonnull", since = "1.25.0")]
-impl<T: ?Sized> PartialOrd for NonNull<T> {
-    #[inline]
-    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        self.as_ptr().partial_cmp(&other.as_ptr())
-    }
-}
-
-#[stable(feature = "nonnull", since = "1.25.0")]
-impl<T: ?Sized> hash::Hash for NonNull<T> {
-    #[inline]
-    fn hash<H: hash::Hasher>(&self, state: &mut H) {
-        self.as_ptr().hash(state)
-    }
-}
-
-#[unstable(feature = "ptr_internals", issue = "0")]
-impl<T: ?Sized> From<Unique<T>> for NonNull<T> {
-    #[inline]
-    fn from(unique: Unique<T>) -> Self {
-        unsafe { NonNull { pointer: unique.pointer } }
-    }
-}
-
-#[stable(feature = "nonnull", since = "1.25.0")]
-impl<T: ?Sized> From<&mut T> for NonNull<T> {
-    #[inline]
-    fn from(reference: &mut T) -> Self {
-        unsafe { NonNull { pointer: reference as *mut T } }
-    }
-}
-
-#[stable(feature = "nonnull", since = "1.25.0")]
-impl<T: ?Sized> From<&T> for NonNull<T> {
-    #[inline]
-    fn from(reference: &T) -> Self {
-        unsafe { NonNull { pointer: reference as *const T } }
-    }
-}
diff --git a/src/libcore/ptr/non_null.rs b/src/libcore/ptr/non_null.rs
new file mode 100644
index 00000000000..0a6985e334c
--- /dev/null
+++ b/src/libcore/ptr/non_null.rs
@@ -0,0 +1,226 @@
+use crate::convert::From;
+use crate::ops::{CoerceUnsized, DispatchFromDyn};
+use crate::fmt;
+use crate::hash;
+use crate::marker::Unsize;
+use crate::mem;
+use crate::ptr::Unique;
+use crate::cmp::Ordering;
+
+/// `*mut T` but non-zero and covariant.
+///
+/// This is often the correct thing to use when building data structures using
+/// raw pointers, but is ultimately more dangerous to use because of its additional
+/// properties. If you're not sure if you should use `NonNull<T>`, just use `*mut T`!
+///
+/// Unlike `*mut T`, the pointer must always be non-null, even if the pointer
+/// is never dereferenced. This is so that enums may use this forbidden value
+/// as a discriminant -- `Option<NonNull<T>>` has the same size as `*mut T`.
+/// However the pointer may still dangle if it isn't dereferenced.
+///
+/// Unlike `*mut T`, `NonNull<T>` is covariant over `T`. If this is incorrect
+/// for your use case, you should include some [`PhantomData`] in your type to
+/// provide invariance, such as `PhantomData<Cell<T>>` or `PhantomData<&'a mut T>`.
+/// Usually this won't be necessary; covariance is correct for most safe abstractions,
+/// such as `Box`, `Rc`, `Arc`, `Vec`, and `LinkedList`. This is the case because they
+/// provide a public API that follows the normal shared XOR mutable rules of Rust.
+///
+/// Notice that `NonNull<T>` has a `From` instance for `&T`. However, this does
+/// not change the fact that mutating through a (pointer derived from a) shared
+/// reference is undefined behavior unless the mutation happens inside an
+/// [`UnsafeCell<T>`]. The same goes for creating a mutable reference from a shared
+/// reference. When using this `From` instance without an `UnsafeCell<T>`,
+/// it is your responsibility to ensure that `as_mut` is never called, and `as_ptr`
+/// is never used for mutation.
+///
+/// [`PhantomData`]: ../marker/struct.PhantomData.html
+/// [`UnsafeCell<T>`]: ../cell/struct.UnsafeCell.html
+#[stable(feature = "nonnull", since = "1.25.0")]
+#[repr(transparent)]
+#[rustc_layout_scalar_valid_range_start(1)]
+#[cfg_attr(not(stage0), rustc_nonnull_optimization_guaranteed)]
+pub struct NonNull<T: ?Sized> {
+    pointer: *const T,
+}
+
+/// `NonNull` pointers are not `Send` because the data they reference may be aliased.
+// N.B., this impl is unnecessary, but should provide better error messages.
+#[stable(feature = "nonnull", since = "1.25.0")]
+impl<T: ?Sized> !Send for NonNull<T> { }
+
+/// `NonNull` pointers are not `Sync` because the data they reference may be aliased.
+// N.B., this impl is unnecessary, but should provide better error messages.
+#[stable(feature = "nonnull", since = "1.25.0")]
+impl<T: ?Sized> !Sync for NonNull<T> { }
+
+impl<T: Sized> NonNull<T> {
+    /// Creates a new `NonNull` that is dangling, but well-aligned.
+    ///
+    /// This is useful for initializing types which lazily allocate, like
+    /// `Vec::new` does.
+    ///
+    /// Note that the pointer value may potentially represent a valid pointer to
+    /// a `T`, which means this must not be used as a "not yet initialized"
+    /// sentinel value. Types that lazily allocate must track initialization by
+    /// some other means.
+    #[stable(feature = "nonnull", since = "1.25.0")]
+    #[inline]
+    pub const fn dangling() -> Self {
+        unsafe {
+            let ptr = mem::align_of::<T>() as *mut T;
+            NonNull::new_unchecked(ptr)
+        }
+    }
+}
+
+impl<T: ?Sized> NonNull<T> {
+    /// Creates a new `NonNull`.
+    ///
+    /// # Safety
+    ///
+    /// `ptr` must be non-null.
+    #[stable(feature = "nonnull", since = "1.25.0")]
+    #[inline]
+    pub const unsafe fn new_unchecked(ptr: *mut T) -> Self {
+        NonNull { pointer: ptr as _ }
+    }
+
+    /// Creates a new `NonNull` if `ptr` is non-null.
+    #[stable(feature = "nonnull", since = "1.25.0")]
+    #[inline]
+    pub fn new(ptr: *mut T) -> Option<Self> {
+        if !ptr.is_null() {
+            Some(unsafe { Self::new_unchecked(ptr) })
+        } else {
+            None
+        }
+    }
+
+    /// Acquires the underlying `*mut` pointer.
+    #[stable(feature = "nonnull", since = "1.25.0")]
+    #[inline]
+    pub const fn as_ptr(self) -> *mut T {
+        self.pointer as *mut T
+    }
+
+    /// Dereferences the content.
+    ///
+    /// The resulting lifetime is bound to self so this behaves "as if"
+    /// it were actually an instance of T that is getting borrowed. If a longer
+    /// (unbound) lifetime is needed, use `&*my_ptr.as_ptr()`.
+    #[stable(feature = "nonnull", since = "1.25.0")]
+    #[inline]
+    pub unsafe fn as_ref(&self) -> &T {
+        &*self.as_ptr()
+    }
+
+    /// Mutably dereferences the content.
+    ///
+    /// The resulting lifetime is bound to self so this behaves "as if"
+    /// it were actually an instance of T that is getting borrowed. If a longer
+    /// (unbound) lifetime is needed, use `&mut *my_ptr.as_ptr()`.
+    #[stable(feature = "nonnull", since = "1.25.0")]
+    #[inline]
+    pub unsafe fn as_mut(&mut self) -> &mut T {
+        &mut *self.as_ptr()
+    }
+
+    /// Cast to a pointer of another type
+    #[stable(feature = "nonnull_cast", since = "1.27.0")]
+    #[inline]
+    pub const fn cast<U>(self) -> NonNull<U> {
+        unsafe {
+            NonNull::new_unchecked(self.as_ptr() as *mut U)
+        }
+    }
+}
+
+#[stable(feature = "nonnull", since = "1.25.0")]
+impl<T: ?Sized> Clone for NonNull<T> {
+    #[inline]
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+
+#[stable(feature = "nonnull", since = "1.25.0")]
+impl<T: ?Sized> Copy for NonNull<T> { }
+
+#[unstable(feature = "coerce_unsized", issue = "27732")]
+impl<T: ?Sized, U: ?Sized> CoerceUnsized<NonNull<U>> for NonNull<T> where T: Unsize<U> { }
+
+#[unstable(feature = "dispatch_from_dyn", issue = "0")]
+impl<T: ?Sized, U: ?Sized> DispatchFromDyn<NonNull<U>> for NonNull<T> where T: Unsize<U> { }
+
+#[stable(feature = "nonnull", since = "1.25.0")]
+impl<T: ?Sized> fmt::Debug for NonNull<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Pointer::fmt(&self.as_ptr(), f)
+    }
+}
+
+#[stable(feature = "nonnull", since = "1.25.0")]
+impl<T: ?Sized> fmt::Pointer for NonNull<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Pointer::fmt(&self.as_ptr(), f)
+    }
+}
+
+#[stable(feature = "nonnull", since = "1.25.0")]
+impl<T: ?Sized> Eq for NonNull<T> {}
+
+#[stable(feature = "nonnull", since = "1.25.0")]
+impl<T: ?Sized> PartialEq for NonNull<T> {
+    #[inline]
+    fn eq(&self, other: &Self) -> bool {
+        self.as_ptr() == other.as_ptr()
+    }
+}
+
+#[stable(feature = "nonnull", since = "1.25.0")]
+impl<T: ?Sized> Ord for NonNull<T> {
+    #[inline]
+    fn cmp(&self, other: &Self) -> Ordering {
+        self.as_ptr().cmp(&other.as_ptr())
+    }
+}
+
+#[stable(feature = "nonnull", since = "1.25.0")]
+impl<T: ?Sized> PartialOrd for NonNull<T> {
+    #[inline]
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        self.as_ptr().partial_cmp(&other.as_ptr())
+    }
+}
+
+#[stable(feature = "nonnull", since = "1.25.0")]
+impl<T: ?Sized> hash::Hash for NonNull<T> {
+    #[inline]
+    fn hash<H: hash::Hasher>(&self, state: &mut H) {
+        self.as_ptr().hash(state)
+    }
+}
+
+#[unstable(feature = "ptr_internals", issue = "0")]
+impl<T: ?Sized> From<Unique<T>> for NonNull<T> {
+    #[inline]
+    fn from(unique: Unique<T>) -> Self {
+        unsafe { NonNull::new_unchecked(unique.as_ptr()) }
+    }
+}
+
+#[stable(feature = "nonnull", since = "1.25.0")]
+impl<T: ?Sized> From<&mut T> for NonNull<T> {
+    #[inline]
+    fn from(reference: &mut T) -> Self {
+        unsafe { NonNull { pointer: reference as *mut T } }
+    }
+}
+
+#[stable(feature = "nonnull", since = "1.25.0")]
+impl<T: ?Sized> From<&T> for NonNull<T> {
+    #[inline]
+    fn from(reference: &T) -> Self {
+        unsafe { NonNull { pointer: reference as *const T } }
+    }
+}
diff --git a/src/libcore/ptr/unique.rs b/src/libcore/ptr/unique.rs
new file mode 100644
index 00000000000..5911518919e
--- /dev/null
+++ b/src/libcore/ptr/unique.rs
@@ -0,0 +1,180 @@
+use crate::convert::From;
+use crate::ops::{CoerceUnsized, DispatchFromDyn};
+use crate::fmt;
+use crate::marker::{PhantomData, Unsize};
+use crate::mem;
+use crate::ptr::NonNull;
+
+/// A wrapper around a raw non-null `*mut T` that indicates that the possessor
+/// of this wrapper owns the referent. Useful for building abstractions like
+/// `Box<T>`, `Vec<T>`, `String`, and `HashMap<K, V>`.
+///
+/// Unlike `*mut T`, `Unique<T>` behaves "as if" it were an instance of `T`.
+/// It implements `Send`/`Sync` if `T` is `Send`/`Sync`. It also implies
+/// the kind of strong aliasing guarantees an instance of `T` can expect:
+/// the referent of the pointer should not be modified without a unique path to
+/// its owning Unique.
+///
+/// If you're uncertain of whether it's correct to use `Unique` for your purposes,
+/// consider using `NonNull`, which has weaker semantics.
+///
+/// Unlike `*mut T`, the pointer must always be non-null, even if the pointer
+/// is never dereferenced. This is so that enums may use this forbidden value
+/// as a discriminant -- `Option<Unique<T>>` has the same size as `Unique<T>`.
+/// However the pointer may still dangle if it isn't dereferenced.
+///
+/// Unlike `*mut T`, `Unique<T>` is covariant over `T`. This should always be correct
+/// for any type which upholds Unique's aliasing requirements.
+#[unstable(feature = "ptr_internals", issue = "0",
+           reason = "use NonNull instead and consider PhantomData<T> \
+                     (if you also use #[may_dangle]), Send, and/or Sync")]
+#[doc(hidden)]
+#[repr(transparent)]
+#[rustc_layout_scalar_valid_range_start(1)]
+pub struct Unique<T: ?Sized> {
+    pointer: *const T,
+    // NOTE: this marker has no consequences for variance, but is necessary
+    // for dropck to understand that we logically own a `T`.
+    //
+    // For details, see:
+    // https://github.com/rust-lang/rfcs/blob/master/text/0769-sound-generic-drop.md#phantom-data
+    _marker: PhantomData<T>,
+}
+
+/// `Unique` pointers are `Send` if `T` is `Send` because the data they
+/// reference is unaliased. Note that this aliasing invariant is
+/// unenforced by the type system; the abstraction using the
+/// `Unique` must enforce it.
+#[unstable(feature = "ptr_internals", issue = "0")]
+unsafe impl<T: Send + ?Sized> Send for Unique<T> { }
+
+/// `Unique` pointers are `Sync` if `T` is `Sync` because the data they
+/// reference is unaliased. Note that this aliasing invariant is
+/// unenforced by the type system; the abstraction using the
+/// `Unique` must enforce it.
+#[unstable(feature = "ptr_internals", issue = "0")]
+unsafe impl<T: Sync + ?Sized> Sync for Unique<T> { }
+
+#[unstable(feature = "ptr_internals", issue = "0")]
+impl<T: Sized> Unique<T> {
+    /// Creates a new `Unique` that is dangling, but well-aligned.
+    ///
+    /// This is useful for initializing types which lazily allocate, like
+    /// `Vec::new` does.
+    ///
+    /// Note that the pointer value may potentially represent a valid pointer to
+    /// a `T`, which means this must not be used as a "not yet initialized"
+    /// sentinel value. Types that lazily allocate must track initialization by
+    /// some other means.
+    // FIXME: rename to dangling() to match NonNull?
+    #[inline]
+    pub const fn empty() -> Self {
+        unsafe {
+            Unique::new_unchecked(mem::align_of::<T>() as *mut T)
+        }
+    }
+}
+
+#[unstable(feature = "ptr_internals", issue = "0")]
+impl<T: ?Sized> Unique<T> {
+    /// Creates a new `Unique`.
+    ///
+    /// # Safety
+    ///
+    /// `ptr` must be non-null.
+    #[inline]
+    pub const unsafe fn new_unchecked(ptr: *mut T) -> Self {
+        Unique { pointer: ptr as _, _marker: PhantomData }
+    }
+
+    /// Creates a new `Unique` if `ptr` is non-null.
+    #[inline]
+    pub fn new(ptr: *mut T) -> Option<Self> {
+        if !ptr.is_null() {
+            Some(unsafe { Unique { pointer: ptr as _, _marker: PhantomData } })
+        } else {
+            None
+        }
+    }
+
+    /// Acquires the underlying `*mut` pointer.
+    #[inline]
+    pub const fn as_ptr(self) -> *mut T {
+        self.pointer as *mut T
+    }
+
+    /// Dereferences the content.
+    ///
+    /// The resulting lifetime is bound to self so this behaves "as if"
+    /// it were actually an instance of T that is getting borrowed. If a longer
+    /// (unbound) lifetime is needed, use `&*my_ptr.as_ptr()`.
+    #[inline]
+    pub unsafe fn as_ref(&self) -> &T {
+        &*self.as_ptr()
+    }
+
+    /// Mutably dereferences the content.
+    ///
+    /// The resulting lifetime is bound to self so this behaves "as if"
+    /// it were actually an instance of T that is getting borrowed. If a longer
+    /// (unbound) lifetime is needed, use `&mut *my_ptr.as_ptr()`.
+    #[inline]
+    pub unsafe fn as_mut(&mut self) -> &mut T {
+        &mut *self.as_ptr()
+    }
+}
+
+#[unstable(feature = "ptr_internals", issue = "0")]
+impl<T: ?Sized> Clone for Unique<T> {
+    #[inline]
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+
+#[unstable(feature = "ptr_internals", issue = "0")]
+impl<T: ?Sized> Copy for Unique<T> { }
+
+#[unstable(feature = "ptr_internals", issue = "0")]
+impl<T: ?Sized, U: ?Sized> CoerceUnsized<Unique<U>> for Unique<T> where T: Unsize<U> { }
+
+#[unstable(feature = "ptr_internals", issue = "0")]
+impl<T: ?Sized, U: ?Sized> DispatchFromDyn<Unique<U>> for Unique<T> where T: Unsize<U> { }
+
+#[unstable(feature = "ptr_internals", issue = "0")]
+impl<T: ?Sized> fmt::Debug for Unique<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Pointer::fmt(&self.as_ptr(), f)
+    }
+}
+
+#[unstable(feature = "ptr_internals", issue = "0")]
+impl<T: ?Sized> fmt::Pointer for Unique<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Pointer::fmt(&self.as_ptr(), f)
+    }
+}
+
+#[unstable(feature = "ptr_internals", issue = "0")]
+impl<T: ?Sized> From<&mut T> for Unique<T> {
+    #[inline]
+    fn from(reference: &mut T) -> Self {
+        unsafe { Unique { pointer: reference as *mut T, _marker: PhantomData } }
+    }
+}
+
+#[unstable(feature = "ptr_internals", issue = "0")]
+impl<T: ?Sized> From<&T> for Unique<T> {
+    #[inline]
+    fn from(reference: &T) -> Self {
+        unsafe { Unique { pointer: reference as *const T, _marker: PhantomData } }
+    }
+}
+
+#[unstable(feature = "ptr_internals", issue = "0")]
+impl<'a, T: ?Sized> From<NonNull<T>> for Unique<T> {
+    #[inline]
+    fn from(p: NonNull<T>) -> Self {
+        unsafe { Unique::new_unchecked(p.as_ptr()) }
+    }
+}
diff --git a/src/librustc/mir/interpret/allocation.rs b/src/librustc/mir/interpret/allocation.rs
index 0e2da4c5772..9549a5af5af 100644
--- a/src/librustc/mir/interpret/allocation.rs
+++ b/src/librustc/mir/interpret/allocation.rs
@@ -2,7 +2,6 @@
 
 use super::{
     Pointer, EvalResult, AllocId, ScalarMaybeUndef, write_target_uint, read_target_uint, Scalar,
-    truncate,
 };
 
 use crate::ty::layout::{Size, Align};
@@ -407,18 +406,9 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
             ScalarMaybeUndef::Undef => return self.mark_definedness(ptr, type_size, false),
         };
 
-        let bytes = match val {
-            Scalar::Ptr(val) => {
-                assert_eq!(type_size, cx.data_layout().pointer_size);
-                val.offset.bytes() as u128
-            }
-
-            Scalar::Bits { bits, size } => {
-                assert_eq!(size as u64, type_size.bytes());
-                debug_assert_eq!(truncate(bits, Size::from_bytes(size.into())), bits,
-                    "Unexpected value of size {} when writing to memory", size);
-                bits
-            },
+        let bytes = match val.to_bits_or_ptr(type_size, cx) {
+            Err(val) => val.offset.bytes() as u128,
+            Ok(data) => data,
         };
 
         let endian = cx.data_layout().endian;
diff --git a/src/librustc/mir/interpret/mod.rs b/src/librustc/mir/interpret/mod.rs
index 595ea8bd346..07d22cf991c 100644
--- a/src/librustc/mir/interpret/mod.rs
+++ b/src/librustc/mir/interpret/mod.rs
@@ -349,6 +349,7 @@ impl<'tcx> AllocMap<'tcx> {
     /// illegal and will likely ICE.
     /// This function exists to allow const eval to detect the difference between evaluation-
     /// local dangling pointers and allocations in constants/statics.
+    #[inline]
     pub fn get(&self, id: AllocId) -> Option<AllocKind<'tcx>> {
         self.id_to_kind.get(&id).cloned()
     }
@@ -397,6 +398,7 @@ impl<'tcx> AllocMap<'tcx> {
 // Methods to access integers in the target endianness
 ////////////////////////////////////////////////////////////////////////////////
 
+#[inline]
 pub fn write_target_uint(
     endianness: layout::Endian,
     mut target: &mut [u8],
@@ -409,6 +411,7 @@ pub fn write_target_uint(
     }
 }
 
+#[inline]
 pub fn read_target_uint(endianness: layout::Endian, mut source: &[u8]) -> Result<u128, io::Error> {
     match endianness {
         layout::Endian::Little => source.read_uint128::<LittleEndian>(source.len()),
@@ -420,8 +423,15 @@ pub fn read_target_uint(endianness: layout::Endian, mut source: &[u8]) -> Result
 // Methods to facilitate working with signed integers stored in a u128
 ////////////////////////////////////////////////////////////////////////////////
 
+/// Truncate `value` to `size` bits and then sign-extend it to 128 bits
+/// (i.e., if it is negative, fill with 1's on the left).
+#[inline]
 pub fn sign_extend(value: u128, size: Size) -> u128 {
     let size = size.bits();
+    if size == 0 {
+        // Truncated until nothing is left.
+        return 0;
+    }
     // sign extend
     let shift = 128 - size;
     // shift the unsigned value to the left
@@ -429,8 +439,14 @@ pub fn sign_extend(value: u128, size: Size) -> u128 {
     (((value << shift) as i128) >> shift) as u128
 }
 
+/// Truncate `value` to `size` bits.
+#[inline]
 pub fn truncate(value: u128, size: Size) -> u128 {
     let size = size.bits();
+    if size == 0 {
+        // Truncated until nothing is left.
+        return 0;
+    }
     let shift = 128 - size;
     // truncate (shift left to drop out leftover values, shift right to fill with zeroes)
     (value << shift) >> shift
diff --git a/src/librustc/mir/interpret/pointer.rs b/src/librustc/mir/interpret/pointer.rs
index 9422abc4e6f..9e71399d4fd 100644
--- a/src/librustc/mir/interpret/pointer.rs
+++ b/src/librustc/mir/interpret/pointer.rs
@@ -20,30 +20,20 @@ pub trait PointerArithmetic: layout::HasDataLayout {
         self.data_layout().pointer_size
     }
 
-    //// Trunace the given value to the pointer size; also return whether there was an overflow
+    /// Helper function: truncate given value-"overflowed flag" pair to pointer size and
+    /// update "overflowed flag" if there was an overflow.
+    /// This should be called by all the other methods before returning!
     #[inline]
-    fn truncate_to_ptr(&self, val: u128) -> (u64, bool) {
+    fn truncate_to_ptr(&self, (val, over): (u64, bool)) -> (u64, bool) {
+        let val = val as u128;
         let max_ptr_plus_1 = 1u128 << self.pointer_size().bits();
-        ((val % max_ptr_plus_1) as u64, val >= max_ptr_plus_1)
-    }
-
-    #[inline]
-    fn offset<'tcx>(&self, val: u64, i: u64) -> EvalResult<'tcx, u64> {
-        let (res, over) = self.overflowing_offset(val, i);
-        if over { err!(Overflow(mir::BinOp::Add)) } else { Ok(res) }
+        ((val % max_ptr_plus_1) as u64, over || val >= max_ptr_plus_1)
     }
 
     #[inline]
     fn overflowing_offset(&self, val: u64, i: u64) -> (u64, bool) {
-        let (res, over1) = val.overflowing_add(i);
-        let (res, over2) = self.truncate_to_ptr(u128::from(res));
-        (res, over1 || over2)
-    }
-
-    #[inline]
-    fn signed_offset<'tcx>(&self, val: u64, i: i64) -> EvalResult<'tcx, u64> {
-        let (res, over) = self.overflowing_signed_offset(val, i128::from(i));
-        if over { err!(Overflow(mir::BinOp::Add)) } else { Ok(res) }
+        let res = val.overflowing_add(i);
+        self.truncate_to_ptr(res)
     }
 
     // Overflow checking only works properly on the range from -u64 to +u64.
@@ -51,14 +41,27 @@ pub trait PointerArithmetic: layout::HasDataLayout {
     fn overflowing_signed_offset(&self, val: u64, i: i128) -> (u64, bool) {
         // FIXME: is it possible to over/underflow here?
         if i < 0 {
-            // trickery to ensure that i64::min_value() works fine
-            // this formula only works for true negative values, it panics for zero!
+            // Trickery to ensure that i64::min_value() works fine: compute n = -i.
+            // This formula only works for true negative values, it overflows for zero!
             let n = u64::max_value() - (i as u64) + 1;
-            val.overflowing_sub(n)
+            let res = val.overflowing_sub(n);
+            self.truncate_to_ptr(res)
         } else {
             self.overflowing_offset(val, i as u64)
         }
     }
+
+    #[inline]
+    fn offset<'tcx>(&self, val: u64, i: u64) -> EvalResult<'tcx, u64> {
+        let (res, over) = self.overflowing_offset(val, i);
+        if over { err!(Overflow(mir::BinOp::Add)) } else { Ok(res) }
+    }
+
+    #[inline]
+    fn signed_offset<'tcx>(&self, val: u64, i: i64) -> EvalResult<'tcx, u64> {
+        let (res, over) = self.overflowing_signed_offset(val, i128::from(i));
+        if over { err!(Overflow(mir::BinOp::Add)) } else { Ok(res) }
+    }
 }
 
 impl<T: layout::HasDataLayout> PointerArithmetic for T {}
diff --git a/src/librustc/mir/interpret/value.rs b/src/librustc/mir/interpret/value.rs
index 72545f23f8e..21792b847db 100644
--- a/src/librustc/mir/interpret/value.rs
+++ b/src/librustc/mir/interpret/value.rs
@@ -87,11 +87,11 @@ impl<'tcx> ConstValue<'tcx> {
          RustcEncodable, RustcDecodable, Hash, HashStable)]
 pub enum Scalar<Tag=(), Id=AllocId> {
     /// The raw bytes of a simple value.
-    Bits {
-        /// The first `size` bytes are the value.
+    Raw {
+        /// The first `size` bytes of `data` are the value.
         /// Do not try to read less or more bytes than that. The remaining bytes must be 0.
+        data: u128,
         size: u8,
-        bits: u128,
     },
 
     /// A pointer into an `Allocation`. An `Allocation` in the `memory` module has a list of
@@ -108,16 +108,14 @@ impl<Tag: fmt::Debug, Id: fmt::Debug> fmt::Debug for Scalar<Tag, Id> {
         match self {
             Scalar::Ptr(ptr) =>
                 write!(f, "{:?}", ptr),
-            &Scalar::Bits { bits, size } => {
+            &Scalar::Raw { data, size } => {
+                Scalar::check_data(data, size);
                 if size == 0 {
-                    assert_eq!(bits, 0, "ZST value must be 0");
                     write!(f, "<ZST>")
                 } else {
-                    assert_eq!(truncate(bits, Size::from_bytes(size as u64)), bits,
-                            "Scalar value {:#x} exceeds size of {} bytes", bits, size);
                     // Format as hex number wide enough to fit any value of the given `size`.
-                    // So bits=20, size=1 will be "0x14", but with size=4 it'll be "0x00000014".
-                    write!(f, "0x{:>0width$x}", bits, width=(size*2) as usize)
+                    // So data=20, size=1 will be "0x14", but with size=4 it'll be "0x00000014".
+                    write!(f, "0x{:>0width$x}", data, width=(size*2) as usize)
                 }
             }
         }
@@ -128,17 +126,23 @@ impl<Tag> fmt::Display for Scalar<Tag> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             Scalar::Ptr(_) => write!(f, "a pointer"),
-            Scalar::Bits { bits, .. } => write!(f, "{}", bits),
+            Scalar::Raw { data, .. } => write!(f, "{}", data),
         }
     }
 }
 
 impl<'tcx> Scalar<()> {
+    #[inline(always)]
+    fn check_data(data: u128, size: u8) {
+        debug_assert_eq!(truncate(data, Size::from_bytes(size as u64)), data,
+                         "Scalar value {:#x} exceeds size of {} bytes", data, size);
+    }
+
     #[inline]
     pub fn with_tag<Tag>(self, new_tag: Tag) -> Scalar<Tag> {
         match self {
             Scalar::Ptr(ptr) => Scalar::Ptr(ptr.with_tag(new_tag)),
-            Scalar::Bits { bits, size } => Scalar::Bits { bits, size },
+            Scalar::Raw { data, size } => Scalar::Raw { data, size },
         }
     }
 
@@ -155,31 +159,31 @@ impl<'tcx, Tag> Scalar<Tag> {
     pub fn erase_tag(self) -> Scalar {
         match self {
             Scalar::Ptr(ptr) => Scalar::Ptr(ptr.erase_tag()),
-            Scalar::Bits { bits, size } => Scalar::Bits { bits, size },
+            Scalar::Raw { data, size } => Scalar::Raw { data, size },
         }
     }
 
     #[inline]
     pub fn ptr_null(cx: &impl HasDataLayout) -> Self {
-        Scalar::Bits {
-            bits: 0,
+        Scalar::Raw {
+            data: 0,
             size: cx.data_layout().pointer_size.bytes() as u8,
         }
     }
 
     #[inline]
     pub fn zst() -> Self {
-        Scalar::Bits { bits: 0, size: 0 }
+        Scalar::Raw { data: 0, size: 0 }
     }
 
     #[inline]
     pub fn ptr_offset(self, i: Size, cx: &impl HasDataLayout) -> EvalResult<'tcx, Self> {
         let dl = cx.data_layout();
         match self {
-            Scalar::Bits { bits, size } => {
+            Scalar::Raw { data, size } => {
                 assert_eq!(size as u64, dl.pointer_size.bytes());
-                Ok(Scalar::Bits {
-                    bits: dl.offset(bits as u64, i.bytes())? as u128,
+                Ok(Scalar::Raw {
+                    data: dl.offset(data as u64, i.bytes())? as u128,
                     size,
                 })
             }
@@ -191,10 +195,10 @@ impl<'tcx, Tag> Scalar<Tag> {
     pub fn ptr_wrapping_offset(self, i: Size, cx: &impl HasDataLayout) -> Self {
         let dl = cx.data_layout();
         match self {
-            Scalar::Bits { bits, size } => {
+            Scalar::Raw { data, size } => {
                 assert_eq!(size as u64, dl.pointer_size.bytes());
-                Scalar::Bits {
-                    bits: dl.overflowing_offset(bits as u64, i.bytes()).0 as u128,
+                Scalar::Raw {
+                    data: dl.overflowing_offset(data as u64, i.bytes()).0 as u128,
                     size,
                 }
             }
@@ -206,10 +210,10 @@ impl<'tcx, Tag> Scalar<Tag> {
     pub fn ptr_signed_offset(self, i: i64, cx: &impl HasDataLayout) -> EvalResult<'tcx, Self> {
         let dl = cx.data_layout();
         match self {
-            Scalar::Bits { bits, size } => {
+            Scalar::Raw { data, size } => {
                 assert_eq!(size as u64, dl.pointer_size().bytes());
-                Ok(Scalar::Bits {
-                    bits: dl.signed_offset(bits as u64, i)? as u128,
+                Ok(Scalar::Raw {
+                    data: dl.signed_offset(data as u64, i)? as u128,
                     size,
                 })
             }
@@ -221,10 +225,10 @@ impl<'tcx, Tag> Scalar<Tag> {
     pub fn ptr_wrapping_signed_offset(self, i: i64, cx: &impl HasDataLayout) -> Self {
         let dl = cx.data_layout();
         match self {
-            Scalar::Bits { bits, size } => {
+            Scalar::Raw { data, size } => {
                 assert_eq!(size as u64, dl.pointer_size.bytes());
-                Scalar::Bits {
-                    bits: dl.overflowing_signed_offset(bits as u64, i128::from(i)).0 as u128,
+                Scalar::Raw {
+                    data: dl.overflowing_signed_offset(data as u64, i128::from(i)).0 as u128,
                     size,
                 }
             }
@@ -232,14 +236,14 @@ impl<'tcx, Tag> Scalar<Tag> {
         }
     }
 
-    /// Returns this pointers offset from the allocation base, or from NULL (for
+    /// Returns this pointer's offset from the allocation base, or from NULL (for
     /// integer pointers).
     #[inline]
     pub fn get_ptr_offset(self, cx: &impl HasDataLayout) -> Size {
         match self {
-            Scalar::Bits { bits, size } => {
+            Scalar::Raw { data, size } => {
                 assert_eq!(size as u64, cx.pointer_size().bytes());
-                Size::from_bytes(bits as u64)
+                Size::from_bytes(data as u64)
             }
             Scalar::Ptr(ptr) => ptr.offset,
         }
@@ -248,9 +252,9 @@ impl<'tcx, Tag> Scalar<Tag> {
     #[inline]
     pub fn is_null_ptr(self, cx: &impl HasDataLayout) -> bool {
         match self {
-            Scalar::Bits { bits, size } => {
+            Scalar::Raw { data, size } => {
                 assert_eq!(size as u64, cx.data_layout().pointer_size.bytes());
-                bits == 0
+                data == 0
             },
             Scalar::Ptr(_) => false,
         }
@@ -258,20 +262,22 @@ impl<'tcx, Tag> Scalar<Tag> {
 
     #[inline]
     pub fn from_bool(b: bool) -> Self {
-        Scalar::Bits { bits: b as u128, size: 1 }
+        Scalar::Raw { data: b as u128, size: 1 }
     }
 
     #[inline]
     pub fn from_char(c: char) -> Self {
-        Scalar::Bits { bits: c as u128, size: 4 }
+        Scalar::Raw { data: c as u128, size: 4 }
     }
 
     #[inline]
     pub fn from_uint(i: impl Into<u128>, size: Size) -> Self {
         let i = i.into();
-        debug_assert_eq!(truncate(i, size), i,
-                         "Unsigned value {} does not fit in {} bits", i, size.bits());
-        Scalar::Bits { bits: i, size: size.bytes() as u8 }
+        assert_eq!(
+            truncate(i, size), i,
+            "Unsigned value {:#x} does not fit in {} bits", i, size.bits()
+        );
+        Scalar::Raw { data: i, size: size.bytes() as u8 }
     }
 
     #[inline]
@@ -279,28 +285,51 @@ impl<'tcx, Tag> Scalar<Tag> {
         let i = i.into();
         // `into` performed sign extension, we have to truncate
         let truncated = truncate(i as u128, size);
-        debug_assert_eq!(sign_extend(truncated, size) as i128, i,
-                         "Signed value {} does not fit in {} bits", i, size.bits());
-        Scalar::Bits { bits: truncated, size: size.bytes() as u8 }
+        assert_eq!(
+            sign_extend(truncated, size) as i128, i,
+            "Signed value {:#x} does not fit in {} bits", i, size.bits()
+        );
+        Scalar::Raw { data: truncated, size: size.bytes() as u8 }
     }
 
     #[inline]
     pub fn from_f32(f: f32) -> Self {
-        Scalar::Bits { bits: f.to_bits() as u128, size: 4 }
+        Scalar::Raw { data: f.to_bits() as u128, size: 4 }
     }
 
     #[inline]
     pub fn from_f64(f: f64) -> Self {
-        Scalar::Bits { bits: f.to_bits() as u128, size: 8 }
+        Scalar::Raw { data: f.to_bits() as u128, size: 8 }
+    }
+
+    #[inline]
+    pub fn to_bits_or_ptr(
+        self,
+        target_size: Size,
+        cx: &impl HasDataLayout,
+    ) -> Result<u128, Pointer<Tag>> {
+        match self {
+            Scalar::Raw { data, size } => {
+                assert_eq!(target_size.bytes(), size as u64);
+                assert_ne!(size, 0, "you should never look at the bits of a ZST");
+                Scalar::check_data(data, size);
+                Ok(data)
+            }
+            Scalar::Ptr(ptr) => {
+                assert_eq!(target_size, cx.data_layout().pointer_size);
+                Err(ptr)
+            }
+        }
     }
 
     #[inline]
     pub fn to_bits(self, target_size: Size) -> EvalResult<'tcx, u128> {
         match self {
-            Scalar::Bits { bits, size } => {
+            Scalar::Raw { data, size } => {
                 assert_eq!(target_size.bytes(), size as u64);
-                assert_ne!(size, 0, "to_bits cannot be used with zsts");
-                Ok(bits)
+                assert_ne!(size, 0, "you should never look at the bits of a ZST");
+                Scalar::check_data(data, size);
+                Ok(data)
             }
             Scalar::Ptr(_) => err!(ReadPointerAsBytes),
         }
@@ -309,8 +338,8 @@ impl<'tcx, Tag> Scalar<Tag> {
     #[inline]
     pub fn to_ptr(self) -> EvalResult<'tcx, Pointer<Tag>> {
         match self {
-            Scalar::Bits { bits: 0, .. } => err!(InvalidNullPointerUsage),
-            Scalar::Bits { .. } => err!(ReadBytesAsPointer),
+            Scalar::Raw { data: 0, .. } => err!(InvalidNullPointerUsage),
+            Scalar::Raw { .. } => err!(ReadBytesAsPointer),
             Scalar::Ptr(p) => Ok(p),
         }
     }
@@ -318,7 +347,7 @@ impl<'tcx, Tag> Scalar<Tag> {
     #[inline]
     pub fn is_bits(self) -> bool {
         match self {
-            Scalar::Bits { .. } => true,
+            Scalar::Raw { .. } => true,
             _ => false,
         }
     }
@@ -333,8 +362,8 @@ impl<'tcx, Tag> Scalar<Tag> {
 
     pub fn to_bool(self) -> EvalResult<'tcx, bool> {
         match self {
-            Scalar::Bits { bits: 0, size: 1 } => Ok(false),
-            Scalar::Bits { bits: 1, size: 1 } => Ok(true),
+            Scalar::Raw { data: 0, size: 1 } => Ok(false),
+            Scalar::Raw { data: 1, size: 1 } => Ok(true),
             _ => err!(InvalidBool),
         }
     }
@@ -350,27 +379,23 @@ impl<'tcx, Tag> Scalar<Tag> {
     pub fn to_u8(self) -> EvalResult<'static, u8> {
         let sz = Size::from_bits(8);
         let b = self.to_bits(sz)?;
-        assert_eq!(b as u8 as u128, b);
         Ok(b as u8)
     }
 
     pub fn to_u32(self) -> EvalResult<'static, u32> {
         let sz = Size::from_bits(32);
         let b = self.to_bits(sz)?;
-        assert_eq!(b as u32 as u128, b);
         Ok(b as u32)
     }
 
     pub fn to_u64(self) -> EvalResult<'static, u64> {
         let sz = Size::from_bits(64);
         let b = self.to_bits(sz)?;
-        assert_eq!(b as u64 as u128, b);
         Ok(b as u64)
     }
 
     pub fn to_usize(self, cx: &impl HasDataLayout) -> EvalResult<'static, u64> {
         let b = self.to_bits(cx.data_layout().pointer_size)?;
-        assert_eq!(b as u64 as u128, b);
         Ok(b as u64)
     }
 
@@ -378,7 +403,6 @@ impl<'tcx, Tag> Scalar<Tag> {
         let sz = Size::from_bits(8);
         let b = self.to_bits(sz)?;
         let b = sign_extend(b, sz) as i128;
-        assert_eq!(b as i8 as i128, b);
         Ok(b as i8)
     }
 
@@ -386,7 +410,6 @@ impl<'tcx, Tag> Scalar<Tag> {
         let sz = Size::from_bits(32);
         let b = self.to_bits(sz)?;
         let b = sign_extend(b, sz) as i128;
-        assert_eq!(b as i32 as i128, b);
         Ok(b as i32)
     }
 
@@ -394,14 +417,13 @@ impl<'tcx, Tag> Scalar<Tag> {
         let sz = Size::from_bits(64);
         let b = self.to_bits(sz)?;
         let b = sign_extend(b, sz) as i128;
-        assert_eq!(b as i64 as i128, b);
         Ok(b as i64)
     }
 
     pub fn to_isize(self, cx: &impl HasDataLayout) -> EvalResult<'static, i64> {
-        let b = self.to_bits(cx.data_layout().pointer_size)?;
-        let b = sign_extend(b, cx.data_layout().pointer_size) as i128;
-        assert_eq!(b as i64 as i128, b);
+        let sz = cx.data_layout().pointer_size;
+        let b = self.to_bits(sz)?;
+        let b = sign_extend(b, sz) as i128;
         Ok(b as i64)
     }
 
diff --git a/src/librustc/mir/mod.rs b/src/librustc/mir/mod.rs
index 84aff8101a0..e2a8cd6b17d 100644
--- a/src/librustc/mir/mod.rs
+++ b/src/librustc/mir/mod.rs
@@ -1669,10 +1669,7 @@ impl<'tcx> TerminatorKind<'tcx> {
                         .map(|&u| {
                             tcx.mk_const(ty::Const {
                                 val: ConstValue::Scalar(
-                                    Scalar::Bits {
-                                        bits: u,
-                                        size: size.bytes() as u8,
-                                    }.into(),
+                                    Scalar::from_uint(u, size).into(),
                                 ),
                                 ty: switch_ty,
                             }).to_string().into()
diff --git a/src/librustc/session/config.rs b/src/librustc/session/config.rs
index 44b6e036557..f4ee39d6988 100644
--- a/src/librustc/session/config.rs
+++ b/src/librustc/session/config.rs
@@ -117,16 +117,16 @@ impl LinkerPluginLto {
 }
 
 #[derive(Clone, PartialEq, Hash)]
-pub enum PgoGenerate {
+pub enum SwitchWithOptPath {
     Enabled(Option<PathBuf>),
     Disabled,
 }
 
-impl PgoGenerate {
+impl SwitchWithOptPath {
     pub fn enabled(&self) -> bool {
         match *self {
-            PgoGenerate::Enabled(_) => true,
-            PgoGenerate::Disabled => false,
+            SwitchWithOptPath::Enabled(_) => true,
+            SwitchWithOptPath::Disabled => false,
         }
     }
 }
@@ -834,7 +834,7 @@ macro_rules! options {
         pub const parse_linker_plugin_lto: Option<&str> =
             Some("either a boolean (`yes`, `no`, `on`, `off`, etc), \
                   or the path to the linker plugin");
-        pub const parse_pgo_generate: Option<&str> =
+        pub const parse_switch_with_opt_path: Option<&str> =
             Some("an optional path to the profiling data output directory");
         pub const parse_merge_functions: Option<&str> =
             Some("one of: `disabled`, `trampolines`, or `aliases`");
@@ -842,7 +842,7 @@ macro_rules! options {
 
     #[allow(dead_code)]
     mod $mod_set {
-        use super::{$struct_name, Passes, Sanitizer, LtoCli, LinkerPluginLto, PgoGenerate};
+        use super::{$struct_name, Passes, Sanitizer, LtoCli, LinkerPluginLto, SwitchWithOptPath};
         use rustc_target::spec::{LinkerFlavor, MergeFunctions, PanicStrategy, RelroLevel};
         use std::path::PathBuf;
         use std::str::FromStr;
@@ -1097,10 +1097,10 @@ macro_rules! options {
             true
         }
 
-        fn parse_pgo_generate(slot: &mut PgoGenerate, v: Option<&str>) -> bool {
+        fn parse_switch_with_opt_path(slot: &mut SwitchWithOptPath, v: Option<&str>) -> bool {
             *slot = match v {
-                None => PgoGenerate::Enabled(None),
-                Some(path) => PgoGenerate::Enabled(Some(PathBuf::from(path))),
+                None => SwitchWithOptPath::Enabled(None),
+                Some(path) => SwitchWithOptPath::Enabled(Some(PathBuf::from(path))),
             };
             true
         }
@@ -1379,7 +1379,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "extra arguments to prepend to the linker invocation (space separated)"),
     profile: bool = (false, parse_bool, [TRACKED],
                      "insert profiling code"),
-    pgo_gen: PgoGenerate = (PgoGenerate::Disabled, parse_pgo_generate, [TRACKED],
+    pgo_gen: SwitchWithOptPath = (SwitchWithOptPath::Disabled,
+        parse_switch_with_opt_path, [TRACKED],
         "Generate PGO profile data, to a given file, or to the default location if it's empty."),
     pgo_use: Option<PathBuf> = (None, parse_opt_pathbuf, [TRACKED],
         "Use PGO profile data from the given profile file."),
@@ -1447,7 +1448,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "don't interleave execution of lints; allows benchmarking individual lints"),
     crate_attr: Vec<String> = (Vec::new(), parse_string_push, [TRACKED],
         "inject the given attribute in the crate"),
-    self_profile: bool = (false, parse_bool, [UNTRACKED],
+    self_profile: SwitchWithOptPath = (SwitchWithOptPath::Disabled,
+        parse_switch_with_opt_path, [UNTRACKED],
         "run the self profiler and output the raw event data"),
     self_profile_events: Option<Vec<String>> = (None, parse_opt_comma_list, [UNTRACKED],
         "specifies which kinds of events get recorded by the self profiler"),
@@ -2558,7 +2560,7 @@ mod dep_tracking {
     use std::path::PathBuf;
     use std::collections::hash_map::DefaultHasher;
     use super::{CrateType, DebugInfo, ErrorOutputType, OptLevel, OutputTypes,
-                Passes, Sanitizer, LtoCli, LinkerPluginLto, PgoGenerate};
+                Passes, Sanitizer, LtoCli, LinkerPluginLto, SwitchWithOptPath};
     use syntax::feature_gate::UnstableFeatures;
     use rustc_target::spec::{MergeFunctions, PanicStrategy, RelroLevel, TargetTriple};
     use syntax::edition::Edition;
@@ -2626,7 +2628,7 @@ mod dep_tracking {
     impl_dep_tracking_hash_via_hash!(TargetTriple);
     impl_dep_tracking_hash_via_hash!(Edition);
     impl_dep_tracking_hash_via_hash!(LinkerPluginLto);
-    impl_dep_tracking_hash_via_hash!(PgoGenerate);
+    impl_dep_tracking_hash_via_hash!(SwitchWithOptPath);
 
     impl_dep_tracking_hash_for_sortable_vec_of!(String);
     impl_dep_tracking_hash_for_sortable_vec_of!(PathBuf);
@@ -2694,7 +2696,7 @@ mod tests {
         build_session_options_and_crate_config,
         to_crate_config
     };
-    use crate::session::config::{LtoCli, LinkerPluginLto, PgoGenerate, ExternEntry};
+    use crate::session::config::{LtoCli, LinkerPluginLto, SwitchWithOptPath, ExternEntry};
     use crate::session::build_session;
     use crate::session::search_paths::SearchPath;
     use std::collections::{BTreeMap, BTreeSet};
@@ -3207,7 +3209,7 @@ mod tests {
         assert!(reference.dep_tracking_hash() != opts.dep_tracking_hash());
 
         opts = reference.clone();
-        opts.debugging_opts.pgo_gen = PgoGenerate::Enabled(None);
+        opts.debugging_opts.pgo_gen = SwitchWithOptPath::Enabled(None);
         assert_ne!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
 
         opts = reference.clone();
diff --git a/src/librustc/session/mod.rs b/src/librustc/session/mod.rs
index 3d8092f6e00..974a5bb70e6 100644
--- a/src/librustc/session/mod.rs
+++ b/src/librustc/session/mod.rs
@@ -9,7 +9,7 @@ use crate::lint;
 use crate::lint::builtin::BuiltinLintDiagnostics;
 use crate::middle::allocator::AllocatorKind;
 use crate::middle::dependency_format;
-use crate::session::config::OutputType;
+use crate::session::config::{OutputType, SwitchWithOptPath};
 use crate::session::search_paths::{PathKind, SearchPath};
 use crate::util::nodemap::{FxHashMap, FxHashSet};
 use crate::util::common::{duration_to_secs_str, ErrorReported};
@@ -1137,8 +1137,18 @@ fn build_session_(
     driver_lint_caps: FxHashMap<lint::LintId, lint::Level>,
 ) -> Session {
     let self_profiler =
-        if sopts.debugging_opts.self_profile {
-            let profiler = SelfProfiler::new(&sopts.debugging_opts.self_profile_events);
+        if let SwitchWithOptPath::Enabled(ref d) = sopts.debugging_opts.self_profile {
+            let directory = if let Some(ref directory) = d {
+                directory
+            } else {
+                std::path::Path::new(".")
+            };
+
+            let profiler = SelfProfiler::new(
+                directory,
+                sopts.crate_name.as_ref().map(|s| &s[..]),
+                &sopts.debugging_opts.self_profile_events
+            );
             match profiler {
                 Ok(profiler) => {
                     crate::ty::query::QueryName::register_with_profiler(&profiler);
diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs
index a56fe7d7003..92de3e28d19 100644
--- a/src/librustc/ty/context.rs
+++ b/src/librustc/ty/context.rs
@@ -1001,7 +1001,7 @@ impl<'tcx> CommonConsts<'tcx> {
 
         CommonConsts {
             err: mk_const(ty::Const {
-                val: ConstValue::Scalar(Scalar::Bits { bits: 0, size: 0 }),
+                val: ConstValue::Scalar(Scalar::zst()),
                 ty: types.err,
             }),
         }
diff --git a/src/librustc/ty/print/pretty.rs b/src/librustc/ty/print/pretty.rs
index 4b4dd5d88d9..a246d9652f2 100644
--- a/src/librustc/ty/print/pretty.rs
+++ b/src/librustc/ty/print/pretty.rs
@@ -845,22 +845,22 @@ pub trait PrettyPrinter<'gcx: 'tcx, 'tcx>:
             p!(write("{}", name));
             return Ok(self);
         }
-        if let ConstValue::Scalar(Scalar::Bits { bits, .. }) = ct.val {
+        if let ConstValue::Scalar(Scalar::Raw { data, .. }) = ct.val {
             match ct.ty.sty {
                 ty::Bool => {
-                    p!(write("{}", if bits == 0 { "false" } else { "true" }));
+                    p!(write("{}", if data == 0 { "false" } else { "true" }));
                     return Ok(self);
                 },
                 ty::Float(ast::FloatTy::F32) => {
-                    p!(write("{}f32", Single::from_bits(bits)));
+                    p!(write("{}f32", Single::from_bits(data)));
                     return Ok(self);
                 },
                 ty::Float(ast::FloatTy::F64) => {
-                    p!(write("{}f64", Double::from_bits(bits)));
+                    p!(write("{}f64", Double::from_bits(data)));
                     return Ok(self);
                 },
                 ty::Uint(ui) => {
-                    p!(write("{}{}", bits, ui));
+                    p!(write("{}{}", data, ui));
                     return Ok(self);
                 },
                 ty::Int(i) =>{
@@ -868,11 +868,11 @@ pub trait PrettyPrinter<'gcx: 'tcx, 'tcx>:
                     let size = self.tcx().layout_of(ty::ParamEnv::empty().and(ty))
                         .unwrap()
                         .size;
-                    p!(write("{}{}", sign_extend(bits, size) as i128, i));
+                    p!(write("{}{}", sign_extend(data, size) as i128, i));
                     return Ok(self);
                 },
                 ty::Char => {
-                    p!(write("{:?}", ::std::char::from_u32(bits as u32).unwrap()));
+                    p!(write("{:?}", ::std::char::from_u32(data as u32).unwrap()));
                     return Ok(self);
                 }
                 _ => {},
diff --git a/src/librustc/ty/relate.rs b/src/librustc/ty/relate.rs
index 20493413274..75d227d8067 100644
--- a/src/librustc/ty/relate.rs
+++ b/src/librustc/ty/relate.rs
@@ -613,7 +613,7 @@ where
         (ConstValue::Placeholder(p1), ConstValue::Placeholder(p2)) if p1 == p2 => {
             Ok(a)
         }
-        (ConstValue::Scalar(Scalar::Bits { .. }), _) if a == b => {
+        (ConstValue::Scalar(Scalar::Raw { .. }), _) if a == b => {
             Ok(a)
         }
         (ConstValue::ByRef(..), _) => {
diff --git a/src/librustc/ty/sty.rs b/src/librustc/ty/sty.rs
index 4711429502f..0a673dd380b 100644
--- a/src/librustc/ty/sty.rs
+++ b/src/librustc/ty/sty.rs
@@ -3,7 +3,7 @@
 use crate::hir;
 use crate::hir::def_id::DefId;
 use crate::infer::canonical::Canonical;
-use crate::mir::interpret::{ConstValue, truncate};
+use crate::mir::interpret::ConstValue;
 use crate::middle::region;
 use polonius_engine::Atom;
 use rustc_data_structures::indexed_vec::Idx;
@@ -2232,14 +2232,12 @@ impl<'tcx> Const<'tcx> {
         let size = tcx.layout_of(ty).unwrap_or_else(|e| {
             panic!("could not compute layout for {:?}: {:?}", ty, e)
         }).size;
-        let truncated = truncate(bits, size);
-        assert_eq!(truncated, bits, "from_bits called with untruncated value");
-        Self::from_scalar(tcx, Scalar::Bits { bits, size: size.bytes() as u8 }, ty.value)
+        Self::from_scalar(tcx, Scalar::from_uint(bits, size), ty.value)
     }
 
     #[inline]
     pub fn zero_sized(tcx: TyCtxt<'_, '_, 'tcx>, ty: Ty<'tcx>) -> &'tcx Self {
-        Self::from_scalar(tcx, Scalar::Bits { bits: 0, size: 0 }, ty)
+        Self::from_scalar(tcx, Scalar::zst(), ty)
     }
 
     #[inline]
diff --git a/src/librustc/util/profiling.rs b/src/librustc/util/profiling.rs
index 585970e64df..8624856a4f5 100644
--- a/src/librustc/util/profiling.rs
+++ b/src/librustc/util/profiling.rs
@@ -1,6 +1,8 @@
 use std::borrow::Cow;
 use std::error::Error;
+use std::fs;
 use std::mem::{self, Discriminant};
+use std::path::Path;
 use std::process;
 use std::thread::ThreadId;
 use std::u32;
@@ -71,10 +73,17 @@ pub struct SelfProfiler {
 }
 
 impl SelfProfiler {
-    pub fn new(event_filters: &Option<Vec<String>>) -> Result<SelfProfiler, Box<dyn Error>> {
-        let filename = format!("pid-{}.rustc_profile", process::id());
-        let path = std::path::Path::new(&filename);
-        let profiler = Profiler::new(path)?;
+    pub fn new(
+        output_directory: &Path,
+        crate_name: Option<&str>,
+        event_filters: &Option<Vec<String>>
+    ) -> Result<SelfProfiler, Box<dyn Error>> {
+        fs::create_dir_all(output_directory)?;
+
+        let crate_name = crate_name.unwrap_or("unknown-crate");
+        let filename = format!("{}-{}.rustc_profile", crate_name, process::id());
+        let path = output_directory.join(&filename);
+        let profiler = Profiler::new(&path)?;
 
         let query_event_kind = profiler.alloc_string("Query");
         let generic_activity_event_kind = profiler.alloc_string("GenericActivity");
diff --git a/src/librustc_codegen_llvm/back/write.rs b/src/librustc_codegen_llvm/back/write.rs
index 1eee9ab8c0b..d8a9f681639 100644
--- a/src/librustc_codegen_llvm/back/write.rs
+++ b/src/librustc_codegen_llvm/back/write.rs
@@ -13,7 +13,7 @@ use crate::LlvmCodegenBackend;
 use rustc::hir::def_id::LOCAL_CRATE;
 use rustc_codegen_ssa::back::write::{CodegenContext, ModuleConfig, run_assembler};
 use rustc_codegen_ssa::traits::*;
-use rustc::session::config::{self, OutputType, Passes, Lto, PgoGenerate};
+use rustc::session::config::{self, OutputType, Passes, Lto, SwitchWithOptPath};
 use rustc::session::Session;
 use rustc::ty::TyCtxt;
 use rustc_codegen_ssa::{RLIB_BYTECODE_EXTENSION, ModuleCodegen, CompiledModule};
@@ -707,7 +707,7 @@ pub unsafe fn with_llvm_pmb(llmod: &llvm::Module,
     let inline_threshold = config.inline_threshold;
 
     let pgo_gen_path = match config.pgo_gen {
-        PgoGenerate::Enabled(ref opt_dir_path) => {
+        SwitchWithOptPath::Enabled(ref opt_dir_path) => {
             let path = if let Some(dir_path) = opt_dir_path {
                 dir_path.join("default_%m.profraw")
             } else {
@@ -716,7 +716,7 @@ pub unsafe fn with_llvm_pmb(llmod: &llvm::Module,
 
             Some(CString::new(format!("{}", path.display())).unwrap())
         }
-        PgoGenerate::Disabled => {
+        SwitchWithOptPath::Disabled => {
             None
         }
     };
diff --git a/src/librustc_codegen_llvm/common.rs b/src/librustc_codegen_llvm/common.rs
index b9fd9629e6f..c713362440d 100644
--- a/src/librustc_codegen_llvm/common.rs
+++ b/src/librustc_codegen_llvm/common.rs
@@ -294,13 +294,13 @@ impl ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
     ) -> &'ll Value {
         let bitsize = if layout.is_bool() { 1 } else { layout.value.size(self).bits() };
         match cv {
-            Scalar::Bits { size: 0, .. } => {
+            Scalar::Raw { size: 0, .. } => {
                 assert_eq!(0, layout.value.size(self).bytes());
                 self.const_undef(self.type_ix(0))
             },
-            Scalar::Bits { bits, size } => {
+            Scalar::Raw { data, size } => {
                 assert_eq!(size as u64, layout.value.size(self).bytes());
-                let llval = self.const_uint_big(self.type_ix(bitsize), bits);
+                let llval = self.const_uint_big(self.type_ix(bitsize), data);
                 if layout.value == layout::Pointer {
                     unsafe { llvm::LLVMConstIntToPtr(llval, llty) }
                 } else {
diff --git a/src/librustc_codegen_ssa/back/write.rs b/src/librustc_codegen_ssa/back/write.rs
index 74c41969268..5abff2d8ec3 100644
--- a/src/librustc_codegen_ssa/back/write.rs
+++ b/src/librustc_codegen_ssa/back/write.rs
@@ -13,7 +13,7 @@ use rustc::dep_graph::{WorkProduct, WorkProductId, WorkProductFileKind};
 use rustc::dep_graph::cgu_reuse_tracker::CguReuseTracker;
 use rustc::middle::cstore::EncodedMetadata;
 use rustc::session::config::{self, OutputFilenames, OutputType, Passes, Lto,
-                             Sanitizer, PgoGenerate};
+                             Sanitizer, SwitchWithOptPath};
 use rustc::session::Session;
 use rustc::util::nodemap::FxHashMap;
 use rustc::hir::def_id::{CrateNum, LOCAL_CRATE};
@@ -56,7 +56,7 @@ pub struct ModuleConfig {
     /// Some(level) to optimize binary size, or None to not affect program size.
     pub opt_size: Option<config::OptLevel>,
 
-    pub pgo_gen: PgoGenerate,
+    pub pgo_gen: SwitchWithOptPath,
     pub pgo_use: Option<PathBuf>,
 
     // Flags indicating which outputs to produce.
@@ -94,7 +94,7 @@ impl ModuleConfig {
             opt_level: None,
             opt_size: None,
 
-            pgo_gen: PgoGenerate::Disabled,
+            pgo_gen: SwitchWithOptPath::Disabled,
             pgo_use: None,
 
             emit_no_opt_bc: false,
diff --git a/src/librustc_codegen_utils/symbol_names.rs b/src/librustc_codegen_utils/symbol_names.rs
index 86407162907..bf81b7f0da5 100644
--- a/src/librustc_codegen_utils/symbol_names.rs
+++ b/src/librustc_codegen_utils/symbol_names.rs
@@ -443,7 +443,7 @@ impl Printer<'tcx, 'tcx> for SymbolPrinter<'_, 'tcx> {
         ct: &'tcx ty::Const<'tcx>,
     ) -> Result<Self::Const, Self::Error> {
         // only print integers
-        if let ConstValue::Scalar(Scalar::Bits { .. }) = ct.val {
+        if let ConstValue::Scalar(Scalar::Raw { .. }) = ct.val {
             if ct.ty.is_integral() {
                 return self.pretty_print_const(ct);
             }
diff --git a/src/librustc_mir/const_eval.rs b/src/librustc_mir/const_eval.rs
index c43bc41ba68..7b3d0bceb68 100644
--- a/src/librustc_mir/const_eval.rs
+++ b/src/librustc_mir/const_eval.rs
@@ -115,7 +115,7 @@ fn op_to_const<'tcx>(
                     ecx.tcx.alloc_map.lock().unwrap_memory(ptr.alloc_id),
                     ptr.offset.bytes(),
                 ),
-                Scalar::Bits { .. } => (
+                Scalar::Raw { .. } => (
                     ecx.tcx.intern_const_alloc(Allocation::from_byte_aligned_bytes(b"", ())),
                     0,
                 ),
diff --git a/src/librustc_mir/hair/constant.rs b/src/librustc_mir/hair/constant.rs
index d2c86d36238..69df36348a6 100644
--- a/src/librustc_mir/hair/constant.rs
+++ b/src/librustc_mir/hair/constant.rs
@@ -1,5 +1,5 @@
 use syntax::ast;
-use rustc::ty::{self, Ty, TyCtxt, ParamEnv};
+use rustc::ty::{self, Ty, TyCtxt, ParamEnv, layout::Size};
 use syntax_pos::symbol::Symbol;
 use rustc::mir::interpret::{ConstValue, Scalar};
 
@@ -23,10 +23,7 @@ crate fn lit_to_const<'a, 'gcx, 'tcx>(
         trace!("trunc {} with size {} and shift {}", n, width.bits(), 128 - width.bits());
         let result = truncate(n, width);
         trace!("trunc result: {}", result);
-        Ok(ConstValue::Scalar(Scalar::Bits {
-            bits: result,
-            size: width.bytes() as u8,
-        }))
+        Ok(ConstValue::Scalar(Scalar::from_uint(result, width)))
     };
 
     use rustc::mir::interpret::*;
@@ -50,10 +47,7 @@ crate fn lit_to_const<'a, 'gcx, 'tcx>(
             let id = tcx.allocate_bytes(data);
             ConstValue::Scalar(Scalar::Ptr(id.into()))
         },
-        LitKind::Byte(n) => ConstValue::Scalar(Scalar::Bits {
-            bits: n as u128,
-            size: 1,
-        }),
+        LitKind::Byte(n) => ConstValue::Scalar(Scalar::from_uint(n, Size::from_bytes(1))),
         LitKind::Int(n, _) if neg => {
             let n = n as i128;
             let n = n.overflowing_neg().0;
@@ -84,7 +78,7 @@ fn parse_float<'tcx>(
     let num = num.as_str();
     use rustc_apfloat::ieee::{Single, Double};
     use rustc_apfloat::Float;
-    let (bits, size) = match fty {
+    let (data, size) = match fty {
         ast::FloatTy::F32 => {
             num.parse::<f32>().map_err(|_| ())?;
             let mut f = num.parse::<Single>().unwrap_or_else(|e| {
@@ -107,5 +101,5 @@ fn parse_float<'tcx>(
         }
     };
 
-    Ok(ConstValue::Scalar(Scalar::Bits { bits, size }))
+    Ok(ConstValue::Scalar(Scalar::from_uint(data, Size::from_bytes(size))))
 }
diff --git a/src/librustc_mir/interpret/cast.rs b/src/librustc_mir/interpret/cast.rs
index 2512525b4bb..76b11ac2fe6 100644
--- a/src/librustc_mir/interpret/cast.rs
+++ b/src/librustc_mir/interpret/cast.rs
@@ -6,7 +6,7 @@ use syntax::symbol::sym;
 
 use rustc_apfloat::ieee::{Single, Double};
 use rustc::mir::interpret::{
-    Scalar, EvalResult, Pointer, PointerArithmetic, InterpError, truncate
+    Scalar, EvalResult, Pointer, PointerArithmetic, InterpError,
 };
 use rustc::mir::CastKind;
 use rustc_apfloat::Float;
@@ -135,29 +135,13 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> InterpretCx<'a, 'mir, 'tcx, M>
         use rustc::ty::TyKind::*;
         trace!("Casting {:?}: {:?} to {:?}", val, src_layout.ty, dest_layout.ty);
 
-        match val {
-            Scalar::Ptr(ptr) => self.cast_from_ptr(ptr, dest_layout.ty),
-            Scalar::Bits { bits, size } => {
-                debug_assert_eq!(size as u64, src_layout.size.bytes());
-                debug_assert_eq!(truncate(bits, Size::from_bytes(size.into())), bits,
-                    "Unexpected value of size {} before casting", size);
-
-                let res = match src_layout.ty.sty {
-                    Float(fty) => self.cast_from_float(bits, fty, dest_layout.ty)?,
-                    _ => self.cast_from_int(bits, src_layout, dest_layout)?,
-                };
-
-                // Sanity check
-                match res {
-                    Scalar::Ptr(_) => bug!("Fabricated a ptr value from an int...?"),
-                    Scalar::Bits { bits, size } => {
-                        debug_assert_eq!(size as u64, dest_layout.size.bytes());
-                        debug_assert_eq!(truncate(bits, Size::from_bytes(size.into())), bits,
-                            "Unexpected value of size {} after casting", size);
-                    }
+        match val.to_bits_or_ptr(src_layout.size, self) {
+            Err(ptr) => self.cast_from_ptr(ptr, dest_layout.ty),
+            Ok(data) => {
+                match src_layout.ty.sty {
+                    Float(fty) => self.cast_from_float(data, fty, dest_layout.ty),
+                    _ => self.cast_from_int(data, src_layout, dest_layout),
                 }
-                // Done
-                Ok(res)
             }
         }
     }
@@ -177,7 +161,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> InterpretCx<'a, 'mir, 'tcx, M>
         trace!("cast_from_int: {}, {}, {}", v, src_layout.ty, dest_layout.ty);
         use rustc::ty::TyKind::*;
         match dest_layout.ty.sty {
-            Int(_) | Uint(_) => {
+            Int(_) | Uint(_) | RawPtr(_) => {
                 let v = self.truncate(v, dest_layout);
                 Ok(Scalar::from_uint(v, dest_layout.size))
             }
@@ -205,15 +189,6 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> InterpretCx<'a, 'mir, 'tcx, M>
                 Ok(Scalar::from_uint(v, Size::from_bytes(4)))
             },
 
-            // No alignment check needed for raw pointers.
-            // But we have to truncate to target ptr size.
-            RawPtr(_) => {
-                Ok(Scalar::from_uint(
-                    self.truncate_to_ptr(v).0,
-                    self.pointer_size(),
-                ))
-            },
-
             // Casts to bool are not permitted by rustc, no need to handle them here.
             _ => err!(Unimplemented(format!("int to {:?} cast", dest_layout.ty))),
         }
diff --git a/src/librustc_mir/interpret/memory.rs b/src/librustc_mir/interpret/memory.rs
index 0cd258825ac..65a3b04c8b1 100644
--- a/src/librustc_mir/interpret/memory.rs
+++ b/src/librustc_mir/interpret/memory.rs
@@ -12,7 +12,6 @@ use std::borrow::Cow;
 
 use rustc::ty::{self, Instance, ParamEnv, query::TyCtxtAt};
 use rustc::ty::layout::{Align, TargetDataLayout, Size, HasDataLayout};
-pub use rustc::mir::interpret::{truncate, write_target_uint, read_target_uint};
 use rustc_data_structures::fx::{FxHashSet, FxHashMap};
 
 use syntax::ast::Mutability;
@@ -248,23 +247,21 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Memory<'a, 'mir, 'tcx, M> {
         required_align: Align
     ) -> EvalResult<'tcx> {
         // Check non-NULL/Undef, extract offset
-        let (offset, alloc_align) = match ptr {
-            Scalar::Ptr(ptr) => {
+        let (offset, alloc_align) = match ptr.to_bits_or_ptr(self.pointer_size(), self) {
+            Err(ptr) => {
                 // check this is not NULL -- which we can ensure only if this is in-bounds
                 // of some (potentially dead) allocation.
                 let align = self.check_bounds_ptr(ptr, InboundsCheck::MaybeDead,
                                                   CheckInAllocMsg::NullPointerTest)?;
                 (ptr.offset.bytes(), align)
             }
-            Scalar::Bits { bits, size } => {
-                assert_eq!(size as u64, self.pointer_size().bytes());
-                assert!(bits < (1u128 << self.pointer_size().bits()));
+            Ok(data) => {
                 // check this is not NULL
-                if bits == 0 {
+                if data == 0 {
                     return err!(InvalidNullPointerUsage);
                 }
                 // the "base address" is 0 and hence always aligned
-                (bits as u64, required_align)
+                (data as u64, required_align)
             }
         };
         // Check alignment
diff --git a/src/librustc_mir/interpret/operand.rs b/src/librustc_mir/interpret/operand.rs
index c03b35c40c6..289379f34a9 100644
--- a/src/librustc_mir/interpret/operand.rs
+++ b/src/librustc_mir/interpret/operand.rs
@@ -641,19 +641,20 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> InterpretCx<'a, 'mir, 'tcx, M>
             } => {
                 let variants_start = niche_variants.start().as_u32() as u128;
                 let variants_end = niche_variants.end().as_u32() as u128;
-                match raw_discr {
-                    ScalarMaybeUndef::Scalar(Scalar::Ptr(ptr)) => {
+                let raw_discr = raw_discr.not_undef()
+                    .map_err(|_| InterpError::InvalidDiscriminant(ScalarMaybeUndef::Undef))?;
+                match raw_discr.to_bits_or_ptr(discr_val.layout.size, self) {
+                    Err(ptr) => {
                         // The niche must be just 0 (which an inbounds pointer value never is)
                         let ptr_valid = niche_start == 0 && variants_start == variants_end &&
                             self.memory.check_bounds_ptr(ptr, InboundsCheck::MaybeDead,
                                                          CheckInAllocMsg::NullPointerTest).is_ok();
                         if !ptr_valid {
-                            return err!(InvalidDiscriminant(raw_discr.erase_tag()));
+                            return err!(InvalidDiscriminant(raw_discr.erase_tag().into()));
                         }
                         (dataful_variant.as_u32() as u128, dataful_variant)
                     },
-                    ScalarMaybeUndef::Scalar(Scalar::Bits { bits: raw_discr, size }) => {
-                        assert_eq!(size as u64, discr_val.layout.size.bytes());
+                    Ok(raw_discr) => {
                         let adjusted_discr = raw_discr.wrapping_sub(niche_start)
                             .wrapping_add(variants_start);
                         if variants_start <= adjusted_discr && adjusted_discr <= variants_end {
@@ -668,8 +669,6 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> InterpretCx<'a, 'mir, 'tcx, M>
                             (dataful_variant.as_u32() as u128, dataful_variant)
                         }
                     },
-                    ScalarMaybeUndef::Undef =>
-                        return err!(InvalidDiscriminant(ScalarMaybeUndef::Undef)),
                 }
             }
         })
diff --git a/src/librustc_mir/interpret/place.rs b/src/librustc_mir/interpret/place.rs
index 57d5ab71eca..0ae4e90b7c2 100644
--- a/src/librustc_mir/interpret/place.rs
+++ b/src/librustc_mir/interpret/place.rs
@@ -686,7 +686,7 @@ where
                 Immediate::Scalar(ScalarMaybeUndef::Scalar(Scalar::Ptr(_))) =>
                     assert_eq!(self.pointer_size(), dest.layout.size,
                         "Size mismatch when writing pointer"),
-                Immediate::Scalar(ScalarMaybeUndef::Scalar(Scalar::Bits { size, .. })) =>
+                Immediate::Scalar(ScalarMaybeUndef::Scalar(Scalar::Raw { size, .. })) =>
                     assert_eq!(Size::from_bytes(size.into()), dest.layout.size,
                         "Size mismatch when writing bits"),
                 Immediate::Scalar(ScalarMaybeUndef::Undef) => {}, // undef can have any size
diff --git a/src/librustc_mir/interpret/snapshot.rs b/src/librustc_mir/interpret/snapshot.rs
index 83bd3666b3d..c0bc7ce6b39 100644
--- a/src/librustc_mir/interpret/snapshot.rs
+++ b/src/librustc_mir/interpret/snapshot.rs
@@ -186,9 +186,9 @@ impl<'a, Ctx> Snapshot<'a, Ctx> for Scalar
     fn snapshot(&self, ctx: &'a Ctx) -> Self::Item {
         match self {
             Scalar::Ptr(p) => Scalar::Ptr(p.snapshot(ctx)),
-            Scalar::Bits{ size, bits } => Scalar::Bits {
+            Scalar::Raw{ size, data } => Scalar::Raw {
+                data: *data,
                 size: *size,
-                bits: *bits,
             },
         }
     }
diff --git a/src/librustc_mir/interpret/validity.rs b/src/librustc_mir/interpret/validity.rs
index f9401d97635..072c6f4fd90 100644
--- a/src/librustc_mir/interpret/validity.rs
+++ b/src/librustc_mir/interpret/validity.rs
@@ -480,8 +480,8 @@ impl<'rt, 'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>>
                 wrapping_range_format(&layout.valid_range, max_hi),
             )
         );
-        let bits = match value {
-            Scalar::Ptr(ptr) => {
+        let bits = match value.to_bits_or_ptr(op.layout.size, self.ecx) {
+            Err(ptr) => {
                 if lo == 1 && hi == max_hi {
                     // only NULL is not allowed.
                     // We can call `check_align` to check non-NULL-ness, but have to also look
@@ -509,10 +509,8 @@ impl<'rt, 'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>>
                     );
                 }
             }
-            Scalar::Bits { bits, size } => {
-                assert_eq!(size as u64, op.layout.size.bytes());
-                bits
-            }
+            Ok(data) =>
+                data
         };
         // Now compare. This is slightly subtle because this is a special "wrap-around" range.
         if wrapping_range_contains(&layout.valid_range, bits) {
diff --git a/src/librustc_mir/transform/const_prop.rs b/src/librustc_mir/transform/const_prop.rs
index 11022be097c..c46b439f4d3 100644
--- a/src/librustc_mir/transform/const_prop.rs
+++ b/src/librustc_mir/transform/const_prop.rs
@@ -382,10 +382,7 @@ impl<'a, 'mir, 'tcx> ConstPropagator<'a, 'mir, 'tcx> {
                 type_size_of(self.tcx, self.param_env, ty).and_then(|n| Some(
                     ImmTy {
                         imm: Immediate::Scalar(
-                            Scalar::Bits {
-                                bits: n as u128,
-                                size: self.tcx.data_layout.pointer_size.bytes() as u8,
-                            }.into()
+                            Scalar::from_uint(n, self.tcx.data_layout.pointer_size).into()
                         ),
                         layout: self.tcx.layout_of(self.param_env.and(self.tcx.types.usize)).ok()?,
                     }.into()
@@ -713,18 +710,18 @@ impl<'b, 'a, 'tcx> MutVisitor<'tcx> for ConstPropagator<'b, 'a, 'tcx> {
                                     .eval_operand(len, source_info)
                                     .expect("len must be const");
                                 let len = match self.ecx.read_scalar(len) {
-                                    Ok(ScalarMaybeUndef::Scalar(Scalar::Bits {
-                                        bits, ..
-                                    })) => bits,
+                                    Ok(ScalarMaybeUndef::Scalar(Scalar::Raw {
+                                        data, ..
+                                    })) => data,
                                     other => bug!("const len not primitive: {:?}", other),
                                 };
                                 let index = self
                                     .eval_operand(index, source_info)
                                     .expect("index must be const");
                                 let index = match self.ecx.read_scalar(index) {
-                                    Ok(ScalarMaybeUndef::Scalar(Scalar::Bits {
-                                        bits, ..
-                                    })) => bits,
+                                    Ok(ScalarMaybeUndef::Scalar(Scalar::Raw {
+                                        data, ..
+                                    })) => data,
                                     other => bug!("const index not primitive: {:?}", other),
                                 };
                                 format!(
diff --git a/src/test/run-make-fulldeps/print-target-list/Makefile b/src/test/run-make-fulldeps/print-target-list/Makefile
index 144c5ba10cc..5f10f2aa3b0 100644
--- a/src/test/run-make-fulldeps/print-target-list/Makefile
+++ b/src/test/run-make-fulldeps/print-target-list/Makefile
@@ -2,14 +2,7 @@
 
 # Checks that all the targets returned by `rustc --print target-list` are valid
 # target specifications
-# TODO remove the '*ios*' case when rust-lang/rust#29812 is fixed
 all:
 	for target in $(shell $(BARE_RUSTC) --print target-list); do \
-		case $$target in \
-			*ios*) \
-				;; \
-			*) \
-				$(BARE_RUSTC) --target $$target --print sysroot \
-				;; \
-			esac \
+		$(BARE_RUSTC) --target $$target --print sysroot; \
 	done