Merge from rustc

Author: saethlin

src/machine.rs

@@ -777,10 +777,11 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
 
     type Provenance = Provenance;
     type ProvenanceExtra = ProvenanceExtra;
+    type Bytes = Box<[u8]>;
 
     type MemoryMap = MonoHashMap<
         AllocId,
-        (MemoryKind<MiriMemoryKind>, Allocation<Provenance, Self::AllocExtra>),
+        (MemoryKind<MiriMemoryKind>, Allocation<Provenance, Self::AllocExtra, Self::Bytes>),
     >;
 
     const GLOBAL_KIND: Option<MiriMemoryKind> = Some(MiriMemoryKind::Global);