Add From instances for Pointer -> ScalarMaybeUndef and Pointer -> Immediate

Author: RalfJung

src/librustc/mir/interpret/value.rs

@@ -471,6 +471,13 @@ impl<Tag> From<Scalar<Tag>> for ScalarMaybeUndef<Tag> {
     }
 }
 
+impl<Tag> From<Pointer<Tag>> for ScalarMaybeUndef<Tag> {
+    #[inline(always)]
+    fn from(s: Pointer<Tag>) -> Self {
+        ScalarMaybeUndef::Scalar(s.into())
+    }
+}
+
 impl<Tag: fmt::Debug, Id: fmt::Debug> fmt::Debug for ScalarMaybeUndef<Tag, Id> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {

src/librustc_mir/interpret/cast.rs

@@ -55,7 +55,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                         ).ok_or_else(|| err_inval!(TooGeneric))?;
 
                         let fn_ptr = self.memory.create_fn_alloc(FnVal::Instance(instance));
-                        self.write_scalar(Scalar::Ptr(fn_ptr.into()), dest)?;
+                        self.write_scalar(fn_ptr, dest)?;
                     }
                     _ => bug!("reify fn pointer on {:?}", src.layout.ty),
                 }
@@ -88,8 +88,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                             ty::ClosureKind::FnOnce,
                         );
                         let fn_ptr = self.memory.create_fn_alloc(FnVal::Instance(instance));
-                        let val = Immediate::Scalar(Scalar::Ptr(fn_ptr.into()).into());
-                        self.write_immediate(val, dest)?;
+                        self.write_scalar(fn_ptr, dest)?;
                     }
                     _ => bug!("closure fn pointer on {:?}", src.layout.ty),
                 }

src/librustc_mir/interpret/memory.rs

@@ -350,7 +350,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
             sptr
         } else {
             // A "real" access, we must get a pointer.
-            Scalar::Ptr(self.force_ptr(sptr)?)
+            Scalar::from(self.force_ptr(sptr)?)
         };
         Ok(match normalized.to_bits_or_ptr(self.pointer_size(), self) {
             Ok(bits) => {

src/librustc_mir/interpret/operand.rs

@@ -47,6 +47,13 @@ impl<Tag> From<Scalar<Tag>> for Immediate<Tag> {
     }
 }
 
+impl<Tag> From<Pointer<Tag>> for Immediate<Tag> {
+    #[inline(always)]
+    fn from(val: Pointer<Tag>) -> Self {
+        Immediate::Scalar(Scalar::from(val).into())
+    }
+}
+
 impl<'tcx, Tag> Immediate<Tag> {
     pub fn new_slice(
         val: Scalar<Tag>,
@@ -60,7 +67,7 @@ impl<'tcx, Tag> Immediate<Tag> {
     }
 
     pub fn new_dyn_trait(val: Scalar<Tag>, vtable: Pointer<Tag>) -> Self {
-        Immediate::ScalarPair(val.into(), Scalar::Ptr(vtable).into())
+        Immediate::ScalarPair(val.into(), vtable.into())
     }
 
     #[inline]

src/librustc_mir/interpret/place.rs

@@ -686,6 +686,7 @@ where
     }
 
     /// Write a scalar to a place
+    #[inline(always)]
     pub fn write_scalar(
         &mut self,
         val: impl Into<ScalarMaybeUndef<M::PointerTag>>,

src/librustc_mir/interpret/traits.rs

@@ -67,7 +67,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         // allocation is correctly aligned as we created it above. Also we're only offsetting by
         // multiples of `ptr_align`, which means that it will stay aligned to `ptr_align`.
         let vtable_alloc = self.memory.get_raw_mut(vtable.alloc_id)?;
-        vtable_alloc.write_ptr_sized(tcx, vtable, Scalar::Ptr(drop).into())?;
+        vtable_alloc.write_ptr_sized(tcx, vtable, drop.into())?;
 
         let size_ptr = vtable.offset(ptr_size, tcx)?;
         vtable_alloc.write_ptr_sized(tcx, size_ptr, Scalar::from_uint(size, ptr_size).into())?;
@@ -87,7 +87,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 // We cannot use `vtable_allic` as we are creating fn ptrs in this loop.
                 let method_ptr = vtable.offset(ptr_size * (3 + i as u64), tcx)?;
                 self.memory.get_raw_mut(vtable.alloc_id)?
-                    .write_ptr_sized(tcx, method_ptr, Scalar::Ptr(fn_ptr).into())?;
+                    .write_ptr_sized(tcx, method_ptr, fn_ptr.into())?;
             }
         }