calling the ptr hooks no longer needs expensive preparation, remove the opt-out

Author: RalfJung

src/librustc_mir/const_eval.rs

@@ -351,7 +351,6 @@ impl<'a, 'mir, 'tcx> interpret::Machine<'a, 'mir, 'tcx>
     type MemoryMap = FxHashMap<AllocId, (MemoryKind<!>, Allocation)>;
 
     const STATIC_KIND: Option<!> = None; // no copying of statics allowed
-    const ENABLE_PTR_TRACKING_HOOKS: bool = false; // we don't have no provenance
 
     #[inline(always)]
     fn enforce_validity(_ecx: &EvalContext<'a, 'mir, 'tcx, Self>) -> bool {

src/librustc_mir/interpret/machine.rs

@@ -95,11 +95,6 @@ pub trait Machine<'a, 'mir, 'tcx>: Sized {
     /// that is added to the memory so that the work is not done twice.
     const STATIC_KIND: Option<Self::MemoryKinds>;
 
-    /// As an optimization, you can prevent the pointer tracking hooks from ever being
-    /// called.  You should only do this if you do not care about provenance tracking.
-    /// This controls the `tag_reference` and `tag_dereference` hooks.
-    const ENABLE_PTR_TRACKING_HOOKS: bool;
-
     /// Whether to enforce the validity invariant
     fn enforce_validity(ecx: &EvalContext<'a, 'mir, 'tcx, Self>) -> bool;
 

src/librustc_mir/interpret/place.rs

@@ -290,16 +290,14 @@ where
         let mplace = MemPlace { ptr, align, meta };
         let mut mplace = MPlaceTy { mplace, layout };
         // Pointer tag tracking might want to adjust the tag.
-        if M::ENABLE_PTR_TRACKING_HOOKS {
-            let mutbl = match val.layout.ty.sty {
-                // `builtin_deref` considers boxes immutable, that's useless for our purposes
-                ty::Ref(_, _, mutbl) => Some(mutbl),
-                ty::Adt(def, _) if def.is_box() => Some(hir::MutMutable),
-                ty::RawPtr(_) => None,
-                _ => bug!("Unexpected pointer type {}", val.layout.ty.sty),
-            };
-            mplace.mplace.ptr = M::tag_dereference(self, mplace, mutbl)?;
-        }
+        let mutbl = match val.layout.ty.sty {
+            // `builtin_deref` considers boxes immutable, that's useless for our purposes
+            ty::Ref(_, _, mutbl) => Some(mutbl),
+            ty::Adt(def, _) if def.is_box() => Some(hir::MutMutable),
+            ty::RawPtr(_) => None,
+            _ => bug!("Unexpected pointer type {}", val.layout.ty.sty),
+        };
+        mplace.mplace.ptr = M::tag_dereference(self, mplace, mutbl)?;
         // Done
         Ok(mplace)
     }