add Align::ONE; add methods to access alloc.extra

compiler/rustc_middle/src/mir/interpret/allocation.rs

@@ -114,7 +114,7 @@ impl<Tag> Allocation<Tag> {
     }
 
     pub fn from_byte_aligned_bytes<'a>(slice: impl Into<Cow<'a, [u8]>>) -> Self {
-        Allocation::from_bytes(slice, Align::from_bytes(1).unwrap())
+        Allocation::from_bytes(slice, Align::ONE)
     }
 
     pub fn uninit(size: Size, align: Align) -> Self {

compiler/rustc_mir/src/interpret/intrinsics.rs

@@ -14,7 +14,7 @@ use rustc_middle::ty;
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::{Ty, TyCtxt};
 use rustc_span::symbol::{sym, Symbol};
-use rustc_target::abi::{Abi, LayoutOf as _, Primitive, Size};
+use rustc_target::abi::{Abi, Align, LayoutOf as _, Primitive, Size};
 
 use super::{
     util::ensure_monomorphic_enough, CheckInAllocMsg, ImmTy, InterpCx, Machine, OpTy, PlaceTy,
@@ -525,7 +525,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         self.memory.check_ptr_access_align(
             min_ptr,
             Size::from_bytes(size),
-            None,
+            Align::ONE,
             CheckInAllocMsg::PointerArithmeticTest,
         )?;
         Ok(offset_ptr)

compiler/rustc_mir/src/interpret/memory.rs

@@ -264,13 +264,12 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
             Some((size, _align)) => size,
             None => self.get_raw(ptr.alloc_id)?.size(),
         };
-        let align = Align::from_bytes(1).unwrap();
         // This will also call the access hooks.
         self.copy(
             ptr.into(),
-            align,
+            Align::ONE,
             new_ptr.into(),
-            align,
+            Align::ONE,
             old_size.min(new_size),
             /*nonoverlapping*/ true,
         )?;
@@ -379,10 +378,10 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
         &self,
         sptr: Scalar<M::PointerTag>,
         size: Size,
-        align: Option<Align>,
+        align: Align,
         msg: CheckInAllocMsg,
     ) -> InterpResult<'tcx> {
-        self.check_and_deref_ptr(sptr, size, align, msg, |ptr| {
+        self.check_and_deref_ptr(sptr, size, Some(align), msg, |ptr| {
             let (size, align) =
                 self.get_size_and_align(ptr.alloc_id, AllocCheck::Dereferenceable)?;
             Ok((size, align, ()))
@@ -604,6 +603,11 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
         }
     }
 
+    /// Return the `extra` field of the given allocation.
+    pub fn get_alloc_extra<'a>(&'a self, id: AllocId) -> InterpResult<'tcx, &'a M::AllocExtra> {
+        Ok(&self.get_raw(id)?.extra)
+    }
+
     /// Gives raw mutable access to the `Allocation`, without bounds or alignment checks.
     /// The caller is responsible for calling the access hooks!
     ///
@@ -664,6 +668,14 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
         }
     }
 
+    /// Return the `extra` field of the given allocation.
+    pub fn get_alloc_extra_mut<'a>(
+        &'a mut self,
+        id: AllocId,
+    ) -> InterpResult<'tcx, &'a mut M::AllocExtra> {
+        Ok(&mut self.get_raw_mut(id)?.0.extra)
+    }
+
     /// Obtain the size and alignment of an allocation, even if that allocation has
     /// been deallocated.
     ///
@@ -688,7 +700,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
                 // The caller requested no function pointers.
                 throw_ub!(DerefFunctionPointer(id))
             } else {
-                Ok((Size::ZERO, Align::from_bytes(1).unwrap()))
+                Ok((Size::ZERO, Align::ONE))
             };
         }
 
@@ -930,7 +942,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
     ///
     /// Performs appropriate bounds checks.
     pub fn read_bytes(&self, sptr: Scalar<M::PointerTag>, size: Size) -> InterpResult<'tcx, &[u8]> {
-        let alloc_ref = match self.get(sptr, size, Align::from_bytes(1).unwrap())? {
+        let alloc_ref = match self.get(sptr, size, Align::ONE)? {
             Some(a) => a,
             None => return Ok(&[]), // zero-sized access
         };
@@ -956,7 +968,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
         assert_eq!(lower, len, "can only write iterators with a precise length");
 
         let size = Size::from_bytes(len);
-        let alloc_ref = match self.get_mut(sptr, size, Align::from_bytes(1).unwrap())? {
+        let alloc_ref = match self.get_mut(sptr, size, Align::ONE)? {
             Some(alloc_ref) => alloc_ref,
             None => {
                 // zero-sized access

compiler/rustc_mir/src/interpret/place.rs

@@ -1031,11 +1031,8 @@ where
     ) -> MPlaceTy<'tcx, M::PointerTag> {
         let ptr = self.memory.allocate_bytes(str.as_bytes(), kind);
         let meta = Scalar::from_machine_usize(u64::try_from(str.len()).unwrap(), self);
-        let mplace = MemPlace {
-            ptr: ptr.into(),
-            align: Align::from_bytes(1).unwrap(),
-            meta: MemPlaceMeta::Meta(meta),
-        };
+        let mplace =
+            MemPlace { ptr: ptr.into(), align: Align::ONE, meta: MemPlaceMeta::Meta(meta) };
 
         let layout = self.layout_of(self.tcx.mk_static_str()).unwrap();
         MPlaceTy { mplace, layout }

compiler/rustc_mir/src/interpret/validity.rs

@@ -329,7 +329,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
                     self.ecx.memory.check_ptr_access_align(
                         vtable,
                         3 * self.ecx.tcx.data_layout.pointer_size, // drop, size, align
-                        Some(self.ecx.tcx.data_layout.pointer_align.abi),
+                        self.ecx.tcx.data_layout.pointer_align.abi,
                         CheckInAllocMsg::InboundsTest, // will anyway be replaced by validity message
                     ),
                     self.path,
@@ -415,7 +415,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
             self.ecx.memory.check_ptr_access_align(
                 place.ptr,
                 size,
-                Some(align),
+                align,
                 CheckInAllocMsg::InboundsTest, // will anyway be replaced by validity message
             ),
             self.path,

compiler/rustc_target/src/abi/mod.rs

@@ -441,6 +441,8 @@ pub struct Align {
 }
 
 impl Align {
+    pub const ONE: Align = Align { pow2: 0 };
+
     #[inline]
     pub fn from_bits(bits: u64) -> Result<Align, String> {
         Align::from_bytes(Size::from_bits(bits).bytes())
@@ -450,7 +452,7 @@ impl Align {
     pub fn from_bytes(align: u64) -> Result<Align, String> {
         // Treat an alignment of 0 bytes like 1-byte alignment.
         if align == 0 {
-            return Ok(Align { pow2: 0 });
+            return Ok(Align::ONE);
         }
 
         #[cold]