rename deref_operand → deref_pointer and some Miri helper functions

Author: RalfJung

compiler/rustc_const_eval/src/const_eval/machine.rs

@@ -214,9 +214,9 @@ impl<'mir, 'tcx: 'mir> CompileTimeEvalContext<'mir, 'tcx> {
             // &str or &&str
             assert!(args.len() == 1);
 
-            let mut msg_place = self.deref_operand(&args[0])?;
+            let mut msg_place = self.deref_pointer(&args[0])?;
             while msg_place.layout.ty.is_ref() {
-                msg_place = self.deref_operand(&msg_place)?;
+                msg_place = self.deref_pointer(&msg_place)?;
             }
 
             let msg = Symbol::intern(self.read_str(&msg_place)?);

compiler/rustc_const_eval/src/const_eval/valtrees.rs

@@ -102,7 +102,7 @@ pub(crate) fn const_to_valtree_inner<'tcx>(
         ty::FnPtr(_) | ty::RawPtr(_) => Err(ValTreeCreationError::NonSupportedType),
 
         ty::Ref(_, _, _)  => {
-            let Ok(derefd_place)= ecx.deref_operand(place) else {
+            let Ok(derefd_place)= ecx.deref_pointer(place) else {
                 return Err(ValTreeCreationError::Other);
             };
             debug!(?derefd_place);

compiler/rustc_const_eval/src/interpret/intrinsics.rs

@@ -144,7 +144,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             }
 
             sym::min_align_of_val | sym::size_of_val => {
-                // Avoid `deref_operand` -- this is not a deref, the ptr does not have to be
+                // Avoid `deref_pointer` -- this is not a deref, the ptr does not have to be
                 // dereferenceable!
                 let place = self.ref_to_mplace(&self.read_immediate(&args[0])?)?;
                 let (size, align) = self
@@ -225,7 +225,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 self.write_scalar(val, dest)?;
             }
             sym::discriminant_value => {
-                let place = self.deref_operand(&args[0])?;
+                let place = self.deref_pointer(&args[0])?;
                 let variant = self.read_discriminant(&place)?;
                 let discr = self.discriminant_for_variant(place.layout, variant)?;
                 self.write_scalar(discr, dest)?;

compiler/rustc_const_eval/src/interpret/place.rs

@@ -419,7 +419,7 @@ where
     ///
     /// Only call this if you are sure the place is "valid" (aligned and inbounds), or do not
     /// want to ever use the place for memory access!
-    /// Generally prefer `deref_operand`.
+    /// Generally prefer `deref_pointer`.
     pub fn ref_to_mplace(
         &self,
         val: &ImmTy<'tcx, M::Provenance>,
@@ -439,8 +439,9 @@ where
     }
 
     /// Take an operand, representing a pointer, and dereference it to a place.
+    /// Corresponds to the `*` operator in Rust.
     #[instrument(skip(self), level = "debug")]
-    pub fn deref_operand(
+    pub fn deref_pointer(
         &self,
         src: &impl Readable<'tcx, M::Provenance>,
     ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::Provenance>> {

compiler/rustc_const_eval/src/interpret/projection.rs

@@ -290,7 +290,7 @@ where
             OpaqueCast(ty) => base.transmute(self.layout_of(ty)?, self)?,
             Field(field, _) => self.project_field(base, field.index())?,
             Downcast(_, variant) => self.project_downcast(base, variant)?,
-            Deref => self.deref_operand(&base.to_op(self)?)?.into(),
+            Deref => self.deref_pointer(&base.to_op(self)?)?.into(),
             Index(local) => {
                 let layout = self.layout_of(self.tcx.types.usize)?;
                 let n = self.local_to_op(self.frame(), local, Some(layout))?;

compiler/rustc_const_eval/src/interpret/terminator.rs

@@ -661,7 +661,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 let receiver_place = loop {
                     match receiver.layout.ty.kind() {
                         ty::Ref(..) | ty::RawPtr(..) => {
-                            // We do *not* use `deref_operand` here: we don't want to conceptually
+                            // We do *not* use `deref_pointer` here: we don't want to conceptually
                             // create a place that must be dereferenceable, since the receiver might
                             // be a raw pointer and (for `*const dyn Trait`) we don't need to
                             // actually access memory to resolve this method.

compiler/rustc_const_eval/src/interpret/validity.rs

@@ -345,6 +345,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
         value: &OpTy<'tcx, M::Provenance>,
         ptr_kind: PointerKind,
     ) -> InterpResult<'tcx> {
+        // Not using `deref_pointer` since we do the dereferenceable check ourselves below.
         let place = self.ecx.ref_to_mplace(&self.read_immediate(value, ptr_kind.into())?)?;
         // Handle wide pointers.
         // Check metadata early, for better diagnostics
@@ -515,9 +516,6 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
                 Ok(true)
             }
             ty::RawPtr(..) => {
-                // We are conservative with uninit for integers, but try to
-                // actually enforce the strict rules for raw pointers (mostly because
-                // that lets us re-use `ref_to_mplace`).
                 let place =
                     self.ecx.ref_to_mplace(&self.read_immediate(value, ExpectedKind::RawPtr)?)?;
                 if place.layout.is_unsized() {

src/tools/miri/src/concurrency/sync.rs

@@ -206,7 +206,7 @@ pub(super) trait EvalContextExtPriv<'mir, 'tcx: 'mir>:
     ) -> InterpResult<'tcx, Option<Id>> {
         let this = self.eval_context_mut();
         let value_place =
-            this.deref_operand_and_offset(lock_op, offset, lock_layout, this.machine.layouts.u32)?;
+            this.deref_pointer_and_offset(lock_op, offset, lock_layout, this.machine.layouts.u32)?;
 
         // Since we are lazy, this update has to be atomic.
         let (old, success) = this

src/tools/miri/src/helpers.rs

@@ -715,9 +715,9 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
     }
 
     /// Dereference a pointer operand to a place using `layout` instead of the pointer's declared type
-    fn deref_operand_as(
+    fn deref_pointer_as(
         &self,
-        op: &OpTy<'tcx, Provenance>,
+        op: &impl Readable<'tcx, Provenance>,
         layout: TyAndLayout<'tcx>,
     ) -> InterpResult<'tcx, MPlaceTy<'tcx, Provenance>> {
         let this = self.eval_context_ref();
@@ -746,15 +746,15 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
     }
 
     /// Calculates the MPlaceTy given the offset and layout of an access on an operand
-    fn deref_operand_and_offset(
+    fn deref_pointer_and_offset(
         &self,
-        op: &OpTy<'tcx, Provenance>,
+        op: &impl Readable<'tcx, Provenance>,
         offset: u64,
         base_layout: TyAndLayout<'tcx>,
         value_layout: TyAndLayout<'tcx>,
     ) -> InterpResult<'tcx, MPlaceTy<'tcx, Provenance>> {
         let this = self.eval_context_ref();
-        let op_place = this.deref_operand_as(op, base_layout)?;
+        let op_place = this.deref_pointer_as(op, base_layout)?;
         let offset = Size::from_bytes(offset);
 
         // Ensure that the access is within bounds.
@@ -763,28 +763,28 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         Ok(value_place)
     }
 
-    fn read_scalar_at_offset(
+    fn deref_pointer_and_read(
         &self,
-        op: &OpTy<'tcx, Provenance>,
+        op: &impl Readable<'tcx, Provenance>,
         offset: u64,
         base_layout: TyAndLayout<'tcx>,
         value_layout: TyAndLayout<'tcx>,
     ) -> InterpResult<'tcx, Scalar<Provenance>> {
         let this = self.eval_context_ref();
-        let value_place = this.deref_operand_and_offset(op, offset, base_layout, value_layout)?;
+        let value_place = this.deref_pointer_and_offset(op, offset, base_layout, value_layout)?;
         this.read_scalar(&value_place)
     }
 
-    fn write_scalar_at_offset(
+    fn deref_pointer_and_write(
         &mut self,
-        op: &OpTy<'tcx, Provenance>,
+        op: &impl Readable<'tcx, Provenance>,
         offset: u64,
         value: impl Into<Scalar<Provenance>>,
         base_layout: TyAndLayout<'tcx>,
         value_layout: TyAndLayout<'tcx>,
     ) -> InterpResult<'tcx, ()> {
         let this = self.eval_context_mut();
-        let value_place = this.deref_operand_and_offset(op, offset, base_layout, value_layout)?;
+        let value_place = this.deref_pointer_and_offset(op, offset, base_layout, value_layout)?;
         this.write_scalar(value, &value_place)
     }
 

src/tools/miri/src/shims/backtrace.rs

@@ -97,7 +97,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
             1 => {
                 let [_flags, buf] = this.check_shim(abi, Abi::Rust, link_name, args)?;
 
-                let buf_place = this.deref_operand(buf)?;
+                let buf_place = this.deref_pointer(buf)?;
 
                 let ptr_layout = this.layout_of(ptr_ty)?;