interpret: get_alloc_info: also return mutability

Author: RalfJung

Diff for: compiler/rustc_const_eval/src/const_eval/eval_queries.rs

@@ -472,7 +472,7 @@ fn report_validation_error<'tcx>(
     backtrace.print_backtrace();
 
     let bytes = ecx.print_alloc_bytes_for_diagnostics(alloc_id);
-    let (size, align, _) = ecx.get_alloc_info(alloc_id);
+    let (size, align, ..) = ecx.get_alloc_info(alloc_id);
     let raw_bytes = errors::RawBytesNote { size: size.bytes(), align: align.bytes(), bytes };
 
     crate::const_eval::report(

Diff for: compiler/rustc_const_eval/src/interpret/memory.rs

@@ -524,7 +524,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         match self.ptr_try_get_alloc_id(ptr, 0) {
             Err(addr) => is_offset_misaligned(addr, align),
             Ok((alloc_id, offset, _prov)) => {
-                let (_size, alloc_align, kind) = self.get_alloc_info(alloc_id);
+                let (_size, alloc_align, kind, _mutbl) = self.get_alloc_info(alloc_id);
                 if let Some(misalign) =
                     M::alignment_check(self, alloc_id, alloc_align, kind, offset, align)
                 {
@@ -818,19 +818,19 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
 
     /// Obtain the size and alignment of an allocation, even if that allocation has
     /// been deallocated.
-    pub fn get_alloc_info(&self, id: AllocId) -> (Size, Align, AllocKind) {
+    pub fn get_alloc_info(&self, id: AllocId) -> (Size, Align, AllocKind, Mutability) {
         // # Regular allocations
         // Don't use `self.get_raw` here as that will
         // a) cause cycles in case `id` refers to a static
         // b) duplicate a global's allocation in miri
         if let Some((_, alloc)) = self.memory.alloc_map.get(id) {
-            return (alloc.size(), alloc.align, AllocKind::LiveData);
+            return (alloc.size(), alloc.align, AllocKind::LiveData, alloc.mutability);
         }
 
         // # Function pointers
         // (both global from `alloc_map` and local from `extra_fn_ptr_map`)
         if self.get_fn_alloc(id).is_some() {
-            return (Size::ZERO, Align::ONE, AllocKind::Function);
+            return (Size::ZERO, Align::ONE, AllocKind::Function, Mutability::Not);
         }
 
         // # Statics
@@ -842,17 +842,17 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 // `ThreadLocalRef`; we can never have a pointer to them as a regular constant value.
                 assert!(!self.tcx.is_thread_local_static(def_id));
 
-                let DefKind::Static { nested, .. } = self.tcx.def_kind(def_id) else {
+                let DefKind::Static { nested, mutability, .. } = self.tcx.def_kind(def_id) else {
                     bug!("GlobalAlloc::Static is not a static")
                 };
 
-                let (size, align) = if nested {
+                let (size, align, mutability) = if nested {
                     // Nested anonymous statics are untyped, so let's get their
                     // size and alignment from the allocation itself. This always
                     // succeeds, as the query is fed at DefId creation time, so no
                     // evaluation actually occurs.
                     let alloc = self.tcx.eval_static_initializer(def_id).unwrap();
-                    (alloc.0.size(), alloc.0.align)
+                    (alloc.0.size(), alloc.0.align, alloc.0.mutability)
                 } else {
                     // Use size and align of the type for everything else. We need
                     // to do that to
@@ -865,22 +865,33 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                         .expect("statics should not have generic parameters");
                     let layout = self.tcx.layout_of(ParamEnv::empty().and(ty)).unwrap();
                     assert!(layout.is_sized());
-                    (layout.size, layout.align.abi)
+                    let mutability = match mutability {
+                        Mutability::Not if !ty.is_freeze(*self.tcx, ParamEnv::empty()) => {
+                            Mutability::Not
+                        }
+                        _ => Mutability::Mut,
+                    };
+                    (layout.size, layout.align.abi, mutability)
                 };
-                (size, align, AllocKind::LiveData)
+                (size, align, AllocKind::LiveData, mutability)
             }
             Some(GlobalAlloc::Memory(alloc)) => {
                 // Need to duplicate the logic here, because the global allocations have
                 // different associated types than the interpreter-local ones.
                 let alloc = alloc.inner();
-                (alloc.size(), alloc.align, AllocKind::LiveData)
+                (alloc.size(), alloc.align, AllocKind::LiveData, alloc.mutability)
             }
             Some(GlobalAlloc::Function { .. }) => {
                 bug!("We already checked function pointers above")
             }
             Some(GlobalAlloc::VTable(..)) => {
                 // No data to be accessed here. But vtables are pointer-aligned.
-                return (Size::ZERO, self.tcx.data_layout.pointer_align.abi, AllocKind::VTable);
+                return (
+                    Size::ZERO,
+                    self.tcx.data_layout.pointer_align.abi,
+                    AllocKind::VTable,
+                    Mutability::Not,
+                );
             }
             // The rest must be dead.
             None => {
@@ -891,7 +902,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                     .dead_alloc_map
                     .get(&id)
                     .expect("deallocated pointers should all be recorded in `dead_alloc_map`");
-                (size, align, AllocKind::Dead)
+                (size, align, AllocKind::Dead, Mutability::Not)
             }
         }
     }
@@ -902,7 +913,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         id: AllocId,
         msg: CheckInAllocMsg,
     ) -> InterpResult<'tcx, (Size, Align)> {
-        let (size, align, kind) = self.get_alloc_info(id);
+        let (size, align, kind, _mutbl) = self.get_alloc_info(id);
         if matches!(kind, AllocKind::Dead) {
             throw_ub!(PointerUseAfterFree(id, msg))
         }
@@ -1458,7 +1469,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 let ptr = scalar.to_pointer(self)?;
                 match self.ptr_try_get_alloc_id(ptr, 0) {
                     Ok((alloc_id, offset, _)) => {
-                        let (size, _align, _kind) = self.get_alloc_info(alloc_id);
+                        let (size, _align, _kind, _mutbl) = self.get_alloc_info(alloc_id);
                         // If the pointer is out-of-bounds, it may be null.
                         // Note that one-past-the-end (offset == size) is still inbounds, and never null.
                         offset > size

Diff for: compiler/rustc_const_eval/src/interpret/validity.rs

@@ -594,7 +594,7 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValidityVisitor<'rt, 'tcx, M> {
                     }
 
                     // Dangling and Mutability check.
-                    let (size, _align, alloc_kind) = self.ecx.get_alloc_info(alloc_id);
+                    let (size, _align, alloc_kind, _mutbl) = self.ecx.get_alloc_info(alloc_id);
                     if alloc_kind == AllocKind::Dead {
                         // This can happen for zero-sized references. We can't have *any* references to
                         // non-existing allocations in const-eval though, interning rejects them all as

Diff for: src/tools/miri/src/alloc_addresses/mod.rs

@@ -157,7 +157,7 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
     ) -> InterpResult<'tcx, u64> {
         let ecx = self.eval_context_ref();
         let mut rng = ecx.machine.rng.borrow_mut();
-        let (size, align, kind) = ecx.get_alloc_info(alloc_id);
+        let (size, align, kind, _mutbl) = ecx.get_alloc_info(alloc_id);
         // This is either called immediately after allocation (and then cached), or when
         // adjusting `tcx` pointers (which never get freed). So assert that we are looking
         // at a live allocation. This also ensures that we never re-assign an address to an

Diff for: src/tools/miri/src/borrow_tracker/mod.rs

@@ -363,7 +363,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
             // If it does exist, then we have the guarantee that the
             // pointer is readable, and the implicit read access inserted
             // will never cause UB on the pointer itself.
-            let (_, _, kind) = this.get_alloc_info(*alloc_id);
+            let (_, _, kind, _mutbl) = this.get_alloc_info(*alloc_id);
             if matches!(kind, AllocKind::LiveData) {
                 let alloc_extra = this.get_alloc_extra(*alloc_id)?; // can still fail for `extern static`
                 let alloc_borrow_tracker = &alloc_extra.borrow_tracker.as_ref().unwrap();

Diff for: src/tools/miri/src/borrow_tracker/stacked_borrows/mod.rs

@@ -626,7 +626,7 @@ trait EvalContextPrivExt<'tcx, 'ecx>: crate::MiriInterpCxExt<'tcx> {
                 return interp_ok(())
             };
 
-            let (_size, _align, alloc_kind) = this.get_alloc_info(alloc_id);
+            let (_size, _align, alloc_kind, _mutbl) = this.get_alloc_info(alloc_id);
             match alloc_kind {
                 AllocKind::LiveData => {
                     // This should have alloc_extra data, but `get_alloc_extra` can still fail
@@ -1017,7 +1017,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         // Function pointers and dead objects don't have an alloc_extra so we ignore them.
         // This is okay because accessing them is UB anyway, no need for any Stacked Borrows checks.
         // NOT using `get_alloc_extra_mut` since this might be a read-only allocation!
-        let (_size, _align, kind) = this.get_alloc_info(alloc_id);
+        let (_size, _align, kind, _mutbl) = this.get_alloc_info(alloc_id);
         match kind {
             AllocKind::LiveData => {
                 // This should have alloc_extra data, but `get_alloc_extra` can still fail

Diff for: src/tools/miri/src/borrow_tracker/tree_borrows/mod.rs

@@ -538,7 +538,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         // Function pointers and dead objects don't have an alloc_extra so we ignore them.
         // This is okay because accessing them is UB anyway, no need for any Tree Borrows checks.
         // NOT using `get_alloc_extra_mut` since this might be a read-only allocation!
-        let (_size, _align, kind) = this.get_alloc_info(alloc_id);
+        let (_size, _align, kind, _mutbl) = this.get_alloc_info(alloc_id);
         match kind {
             AllocKind::LiveData => {
                 // This should have alloc_extra data, but `get_alloc_extra` can still fail

Diff for: src/tools/miri/src/machine.rs

@@ -1125,7 +1125,7 @@ impl<'tcx> Machine<'tcx> for MiriMachine<'tcx> {
             let Provenance::Concrete { alloc_id, .. } = ptr.provenance else {
                 panic!("extern_statics cannot contain wildcards")
             };
-            let (shim_size, shim_align, _kind) = ecx.get_alloc_info(alloc_id);
+            let (shim_size, shim_align, _kind, _mutbl) = ecx.get_alloc_info(alloc_id);
             let def_ty = ecx.tcx.type_of(def_id).instantiate_identity();
             let extern_decl_layout = ecx.tcx.layout_of(ty::ParamEnv::empty().and(def_ty)).unwrap();
             if extern_decl_layout.size != shim_size || extern_decl_layout.align.abi != shim_align {

Diff for: src/tools/miri/src/shims/foreign_items.rs

@@ -409,7 +409,7 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
                     );
                 }
                 if let Ok((alloc_id, offset, ..)) = this.ptr_try_get_alloc_id(ptr, 0) {
-                    let (_size, alloc_align, _kind) = this.get_alloc_info(alloc_id);
+                    let (_size, alloc_align, _kind, _mutbl) = this.get_alloc_info(alloc_id);
                     // If the newly promised alignment is bigger than the native alignment of this
                     // allocation, and bigger than the previously promised alignment, then set it.
                     if align > alloc_align