ctfe interpreter: extend provenance so that it can track whether a pointer is immutable

Author: RalfJung

src/diagnostics.rs

@@ -44,7 +44,7 @@ pub enum TerminationInfo {
     },
     DataRace {
         involves_non_atomic: bool,
-        ptr: Pointer,
+        ptr: Pointer<AllocId>,
         op1: RacingOp,
         op2: RacingOp,
         extra: Option<&'static str>,

src/intptrcast.rs

@@ -256,12 +256,13 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
     /// Convert a relative (tcx) pointer to a Miri pointer.
     fn ptr_from_rel_ptr(
         &self,
-        ptr: Pointer<AllocId>,
+        ptr: Pointer<CtfeProvenance>,
         tag: BorTag,
     ) -> InterpResult<'tcx, Pointer<Provenance>> {
         let ecx = self.eval_context_ref();
 
-        let (alloc_id, offset) = ptr.into_parts(); // offset is relative (AllocId provenance)
+        let (prov, offset) = ptr.into_parts(); // offset is relative (AllocId provenance)
+        let alloc_id = prov.alloc_id();
         let base_addr = ecx.addr_from_alloc_id(alloc_id)?;
 
         // Add offset with the right kind of pointer-overflowing arithmetic.

src/machine.rs

@@ -1175,11 +1175,11 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
 
     fn adjust_alloc_base_pointer(
         ecx: &MiriInterpCx<'mir, 'tcx>,
-        ptr: Pointer<AllocId>,
+        ptr: Pointer<CtfeProvenance>,
     ) -> InterpResult<'tcx, Pointer<Provenance>> {
+        let alloc_id = ptr.provenance.alloc_id();
         if cfg!(debug_assertions) {
             // The machine promises to never call us on thread-local or extern statics.
-            let alloc_id = ptr.provenance;
             match ecx.tcx.try_get_global_alloc(alloc_id) {
                 Some(GlobalAlloc::Static(def_id)) if ecx.tcx.is_thread_local_static(def_id) => {
                     panic!("adjust_alloc_base_pointer called on thread-local static")
@@ -1190,8 +1190,9 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
                 _ => {}
             }
         }
+        // FIXME: can we somehow preserve the immutability of `ptr`?
         let tag = if let Some(borrow_tracker) = &ecx.machine.borrow_tracker {
-            borrow_tracker.borrow_mut().base_ptr_tag(ptr.provenance, &ecx.machine)
+            borrow_tracker.borrow_mut().base_ptr_tag(alloc_id, &ecx.machine)
         } else {
             // Value does not matter, SB is disabled
             BorTag::default()