1 files changed, 82 insertions, 56 deletions

diff --git a/compiler/rustc_abi/src/lib.rs b/compiler/rustc_abi/src/lib.rs
index f4cb459f3..39574ca55 100644
--- a/compiler/rustc_abi/src/lib.rs
+++ b/compiler/rustc_abi/src/lib.rs
@@ -8,6 +8,7 @@ use std::ops::{Add, AddAssign, Mul, RangeInclusive, Sub};
 use std::str::FromStr;
 
 use bitflags::bitflags;
+use rustc_data_structures::intern::Interned;
 #[cfg(feature = "nightly")]
 use rustc_data_structures::stable_hasher::StableOrd;
 use rustc_index::vec::{Idx, IndexVec};
@@ -170,7 +171,9 @@ pub struct TargetDataLayout {
 
     pub instruction_address_space: AddressSpace,
 
-    /// Minimum size of #[repr(C)] enums (default I32 bits)
+    /// Minimum size of #[repr(C)] enums (default c_int::BITS, usually 32)
+    /// Note: This isn't in LLVM's data layout string, it is `short_enum`
+    /// so the only valid spec for LLVM is c_int::BITS or 8
     pub c_enum_min_size: Integer,
 }
 
@@ -267,6 +270,9 @@ impl TargetDataLayout {
                 ["a", ref a @ ..] => dl.aggregate_align = align(a, "a")?,
                 ["f32", ref a @ ..] => dl.f32_align = align(a, "f32")?,
                 ["f64", ref a @ ..] => dl.f64_align = align(a, "f64")?,
+                // FIXME(erikdesjardins): we should be parsing nonzero address spaces
+                // this will require replacing TargetDataLayout::{pointer_size,pointer_align}
+                // with e.g. `fn pointer_size_in(AddressSpace)`
                 [p @ "p", s, ref a @ ..] | [p @ "p0", s, ref a @ ..] => {
                     dl.pointer_size = size(s, p)?;
                     dl.pointer_align = align(a, p)?;
@@ -861,7 +867,7 @@ pub enum Primitive {
     Int(Integer, bool),
     F32,
     F64,
-    Pointer,
+    Pointer(AddressSpace),
 }
 
 impl Primitive {
@@ -872,7 +878,10 @@ impl Primitive {
             Int(i, _) => i.size(),
             F32 => Size::from_bits(32),
             F64 => Size::from_bits(64),
-            Pointer => dl.pointer_size,
+            // FIXME(erikdesjardins): ignoring address space is technically wrong, pointers in
+            // different address spaces can have different sizes
+            // (but TargetDataLayout doesn't currently parse that part of the DL string)
+            Pointer(_) => dl.pointer_size,
         }
     }
 
@@ -883,26 +892,12 @@ impl Primitive {
             Int(i, _) => i.align(dl),
             F32 => dl.f32_align,
             F64 => dl.f64_align,
-            Pointer => dl.pointer_align,
+            // FIXME(erikdesjardins): ignoring address space is technically wrong, pointers in
+            // different address spaces can have different alignments
+            // (but TargetDataLayout doesn't currently parse that part of the DL string)
+            Pointer(_) => dl.pointer_align,
         }
     }
-
-    // FIXME(eddyb) remove, it's trivial thanks to `matches!`.
-    #[inline]
-    pub fn is_float(self) -> bool {
-        matches!(self, F32 | F64)
-    }
-
-    // FIXME(eddyb) remove, it's completely unused.
-    #[inline]
-    pub fn is_int(self) -> bool {
-        matches!(self, Int(..))
-    }
-
-    #[inline]
-    pub fn is_ptr(self) -> bool {
-        matches!(self, Pointer)
-    }
 }
 
 /// Inclusive wrap-around range of valid values, that is, if
@@ -1188,7 +1183,8 @@ impl FieldsShape {
 /// An identifier that specifies the address space that some operation
 /// should operate on. Special address spaces have an effect on code generation,
 /// depending on the target and the address spaces it implements.
-#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
 pub struct AddressSpace(pub u32);
 
 impl AddressSpace {
@@ -1257,9 +1253,9 @@ impl Abi {
 
 #[derive(PartialEq, Eq, Hash, Clone, Debug)]
 #[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
-pub enum Variants<V: Idx> {
+pub enum Variants {
     /// Single enum variants, structs/tuples, unions, and all non-ADTs.
-    Single { index: V },
+    Single { index: VariantIdx },
 
     /// Enum-likes with more than one inhabited variant: each variant comes with
     /// a *discriminant* (usually the same as the variant index but the user can
@@ -1269,15 +1265,15 @@ pub enum Variants<V: Idx> {
     /// For enums, the tag is the sole field of the layout.
     Multiple {
         tag: Scalar,
-        tag_encoding: TagEncoding<V>,
+        tag_encoding: TagEncoding,
         tag_field: usize,
-        variants: IndexVec<V, LayoutS<V>>,
+        variants: IndexVec<VariantIdx, LayoutS>,
     },
 }
 
 #[derive(PartialEq, Eq, Hash, Clone, Debug)]
 #[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
-pub enum TagEncoding<V: Idx> {
+pub enum TagEncoding {
     /// The tag directly stores the discriminant, but possibly with a smaller layout
     /// (so converting the tag to the discriminant can require sign extension).
     Direct,
@@ -1292,7 +1288,11 @@ pub enum TagEncoding<V: Idx> {
     /// For example, `Option<(usize, &T)>`  is represented such that
     /// `None` has a null pointer for the second tuple field, and
     /// `Some` is the identity function (with a non-null reference).
-    Niche { untagged_variant: V, niche_variants: RangeInclusive<V>, niche_start: u128 },
+    Niche {
+        untagged_variant: VariantIdx,
+        niche_variants: RangeInclusive<VariantIdx>,
+        niche_start: u128,
+    },
 }
 
 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
@@ -1379,9 +1379,14 @@ impl Niche {
     }
 }
 
+rustc_index::newtype_index! {
+    #[derive(HashStable_Generic)]
+    pub struct VariantIdx {}
+}
+
 #[derive(PartialEq, Eq, Hash, Clone)]
 #[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
-pub struct LayoutS<V: Idx> {
+pub struct LayoutS {
     /// Says where the fields are located within the layout.
     pub fields: FieldsShape,
 
@@ -1392,7 +1397,7 @@ pub struct LayoutS<V: Idx> {
     ///
     /// To access all fields of this layout, both `fields` and the fields of the active variant
     /// must be taken into account.
-    pub variants: Variants<V>,
+    pub variants: Variants,
 
     /// The `abi` defines how this data is passed between functions, and it defines
     /// value restrictions via `valid_range`.
@@ -1411,13 +1416,13 @@ pub struct LayoutS<V: Idx> {
     pub size: Size,
 }
 
-impl<V: Idx> LayoutS<V> {
+impl LayoutS {
     pub fn scalar<C: HasDataLayout>(cx: &C, scalar: Scalar) -> Self {
         let largest_niche = Niche::from_scalar(cx, Size::ZERO, scalar);
         let size = scalar.size(cx);
         let align = scalar.align(cx);
         LayoutS {
-            variants: Variants::Single { index: V::new(0) },
+            variants: Variants::Single { index: VariantIdx::new(0) },
             fields: FieldsShape::Primitive,
             abi: Abi::Scalar(scalar),
             largest_niche,
@@ -1427,7 +1432,7 @@ impl<V: Idx> LayoutS<V> {
     }
 }
 
-impl<V: Idx> fmt::Debug for LayoutS<V> {
+impl fmt::Debug for LayoutS {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // This is how `Layout` used to print before it become
         // `Interned<LayoutS>`. We print it like this to avoid having to update
@@ -1444,42 +1449,63 @@ impl<V: Idx> fmt::Debug for LayoutS<V> {
     }
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, Debug)]
-pub enum PointerKind {
-    /// Most general case, we know no restrictions to tell LLVM.
-    SharedMutable,
+#[derive(Copy, Clone, PartialEq, Eq, Hash, HashStable_Generic)]
+#[rustc_pass_by_value]
+pub struct Layout<'a>(pub Interned<'a, LayoutS>);
+
+impl<'a> fmt::Debug for Layout<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // See comment on `<LayoutS as Debug>::fmt` above.
+        self.0.0.fmt(f)
+    }
+}
 
-    /// `&T` where `T` contains no `UnsafeCell`, is `dereferenceable`, `noalias` and `readonly`.
-    Frozen,
+impl<'a> Layout<'a> {
+    pub fn fields(self) -> &'a FieldsShape {
+        &self.0.0.fields
+    }
 
-    /// `&mut T` which is `dereferenceable` and `noalias` but not `readonly`.
-    UniqueBorrowed,
+    pub fn variants(self) -> &'a Variants {
+        &self.0.0.variants
+    }
 
-    /// `&mut !Unpin`, which is `dereferenceable` but neither `noalias` nor `readonly`.
-    UniqueBorrowedPinned,
+    pub fn abi(self) -> Abi {
+        self.0.0.abi
+    }
+
+    pub fn largest_niche(self) -> Option<Niche> {
+        self.0.0.largest_niche
+    }
+
+    pub fn align(self) -> AbiAndPrefAlign {
+        self.0.0.align
+    }
 
-    /// `Box<T>`, which is `noalias` (even on return types, unlike the above) but neither `readonly`
-    /// nor `dereferenceable`.
-    UniqueOwned,
+    pub fn size(self) -> Size {
+        self.0.0.size
+    }
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+pub enum PointerKind {
+    /// Shared reference. `frozen` indicates the absence of any `UnsafeCell`.
+    SharedRef { frozen: bool },
+    /// Mutable reference. `unpin` indicates the absence of any pinned data.
+    MutableRef { unpin: bool },
+    /// Box. `unpin` indicates the absence of any pinned data.
+    Box { unpin: bool },
 }
 
+/// Note that this information is advisory only, and backends are free to ignore it.
+/// It can only be used to encode potential optimizations, but no critical information.
 #[derive(Copy, Clone, Debug)]
 pub struct PointeeInfo {
     pub size: Size,
     pub align: Align,
     pub safe: Option<PointerKind>,
-    pub address_space: AddressSpace,
-}
-
-/// Used in `might_permit_raw_init` to indicate the kind of initialisation
-/// that is checked to be valid
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
-pub enum InitKind {
-    Zero,
-    UninitMitigated0x01Fill,
 }
 
-impl<V: Idx> LayoutS<V> {
+impl LayoutS {
     /// Returns `true` if the layout corresponds to an unsized type.
     pub fn is_unsized(&self) -> bool {
         self.abi.is_unsized()