move interpret::MemoryKind::Heap to const eval

compiler/rustc_mir/src/const_eval/machine.rs

@@ -7,6 +7,7 @@ use std::collections::hash_map::Entry;
 use std::hash::Hash;
 
 use rustc_data_structures::fx::FxHashMap;
+use std::fmt;
 
 use rustc_ast::Mutability;
 use rustc_hir::def_id::DefId;
@@ -179,6 +180,28 @@ impl<K: Hash + Eq, V> interpret::AllocMap<K, V> for FxHashMap<K, V> {
 crate type CompileTimeEvalContext<'mir, 'tcx> =
     InterpCx<'mir, 'tcx, CompileTimeInterpreter<'mir, 'tcx>>;
 
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+pub enum MemoryKind {
+    Heap,
+}
+
+impl fmt::Display for MemoryKind {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            MemoryKind::Heap => write!(f, "heap allocation"),
+        }
+    }
+}
+
+impl interpret::MayLeak for MemoryKind {
+    #[inline(always)]
+    fn may_leak(self) -> bool {
+        match self {
+            MemoryKind::Heap => false,
+        }
+    }
+}
+
 impl interpret::MayLeak for ! {
     #[inline(always)]
     fn may_leak(self) -> bool {
@@ -222,6 +245,8 @@ impl<'mir, 'tcx: 'mir> CompileTimeEvalContext<'mir, 'tcx> {
 impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir, 'tcx> {
     compile_time_machine!(<'mir, 'tcx>);
 
+    type MemoryKind = MemoryKind;
+
     type MemoryExtra = MemoryExtra;
 
     fn find_mir_or_eval_fn(
@@ -317,7 +342,7 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
                 let ptr = ecx.memory.allocate(
                     Size::from_bytes(size as u64),
                     align,
-                    interpret::MemoryKind::ConstHeap,
+                    interpret::MemoryKind::Machine(MemoryKind::Heap),
                 );
                 ecx.write_scalar(Scalar::Ptr(ptr), dest)?;
             }

compiler/rustc_mir/src/interpret/intern.rs

@@ -25,19 +25,20 @@ use rustc_target::abi::Size;
 use rustc_ast::Mutability;
 
 use super::{AllocId, Allocation, InterpCx, MPlaceTy, Machine, MemoryKind, Scalar, ValueVisitor};
+use crate::const_eval;
 
-pub trait CompileTimeMachine<'mir, 'tcx> = Machine<
+pub trait CompileTimeMachine<'mir, 'tcx, T> = Machine<
     'mir,
     'tcx,
-    MemoryKind = !,
+    MemoryKind = T,
     PointerTag = (),
     ExtraFnVal = !,
     FrameExtra = (),
     AllocExtra = (),
-    MemoryMap = FxHashMap<AllocId, (MemoryKind<!>, Allocation)>,
+    MemoryMap = FxHashMap<AllocId, (MemoryKind<T>, Allocation)>,
 >;
 
-struct InternVisitor<'rt, 'mir, 'tcx, M: CompileTimeMachine<'mir, 'tcx>> {
+struct InternVisitor<'rt, 'mir, 'tcx, M: CompileTimeMachine<'mir, 'tcx, const_eval::MemoryKind>> {
     /// The ectx from which we intern.
     ecx: &'rt mut InterpCx<'mir, 'tcx, M>,
     /// Previously encountered safe references.
@@ -74,7 +75,7 @@ struct IsStaticOrFn;
 /// `immutable` things might become mutable if `ty` is not frozen.
 /// `ty` can be `None` if there is no potential interior mutability
 /// to account for (e.g. for vtables).
-fn intern_shallow<'rt, 'mir, 'tcx, M: CompileTimeMachine<'mir, 'tcx>>(
+fn intern_shallow<'rt, 'mir, 'tcx, M: CompileTimeMachine<'mir, 'tcx, const_eval::MemoryKind>>(
     ecx: &'rt mut InterpCx<'mir, 'tcx, M>,
     leftover_allocations: &'rt mut FxHashSet<AllocId>,
     alloc_id: AllocId,
@@ -105,7 +106,7 @@ fn intern_shallow<'rt, 'mir, 'tcx, M: CompileTimeMachine<'mir, 'tcx>>(
     // changes in this function.
     match kind {
         MemoryKind::Stack
-        | MemoryKind::ConstHeap
+        | MemoryKind::Machine(const_eval::MemoryKind::Heap)
         | MemoryKind::Vtable
         | MemoryKind::CallerLocation => {}
     }
@@ -141,7 +142,9 @@ fn intern_shallow<'rt, 'mir, 'tcx, M: CompileTimeMachine<'mir, 'tcx>>(
     None
 }
 
-impl<'rt, 'mir, 'tcx, M: CompileTimeMachine<'mir, 'tcx>> InternVisitor<'rt, 'mir, 'tcx, M> {
+impl<'rt, 'mir, 'tcx, M: CompileTimeMachine<'mir, 'tcx, const_eval::MemoryKind>>
+    InternVisitor<'rt, 'mir, 'tcx, M>
+{
     fn intern_shallow(
         &mut self,
         alloc_id: AllocId,
@@ -152,8 +155,8 @@ impl<'rt, 'mir, 'tcx, M: CompileTimeMachine<'mir, 'tcx>> InternVisitor<'rt, 'mir
     }
 }
 
-impl<'rt, 'mir, 'tcx: 'mir, M: CompileTimeMachine<'mir, 'tcx>> ValueVisitor<'mir, 'tcx, M>
-    for InternVisitor<'rt, 'mir, 'tcx, M>
+impl<'rt, 'mir, 'tcx: 'mir, M: CompileTimeMachine<'mir, 'tcx, const_eval::MemoryKind>>
+    ValueVisitor<'mir, 'tcx, M> for InternVisitor<'rt, 'mir, 'tcx, M>
 {
     type V = MPlaceTy<'tcx>;
 
@@ -290,7 +293,7 @@ pub enum InternKind {
 /// Any errors here would anyway be turned into `const_err` lints, whereas validation failures
 /// are hard errors.
 #[tracing::instrument(skip(ecx))]
-pub fn intern_const_alloc_recursive<M: CompileTimeMachine<'mir, 'tcx>>(
+pub fn intern_const_alloc_recursive<M: CompileTimeMachine<'mir, 'tcx, const_eval::MemoryKind>>(
     ecx: &mut InterpCx<'mir, 'tcx, M>,
     intern_kind: InternKind,
     ret: MPlaceTy<'tcx>,
@@ -421,7 +424,9 @@ where
     Ok(())
 }
 
-impl<'mir, 'tcx: 'mir, M: super::intern::CompileTimeMachine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
+impl<'mir, 'tcx: 'mir, M: super::intern::CompileTimeMachine<'mir, 'tcx, !>>
+    InterpCx<'mir, 'tcx, M>
+{
     /// A helper function that allocates memory for the layout given and gives you access to mutate
     /// it. Once your own mutation code is done, the backing `Allocation` is removed from the
     /// current `Memory` and returned.

compiler/rustc_mir/src/interpret/machine.rs

@@ -366,9 +366,9 @@ pub macro compile_time_machine(<$mir: lifetime, $tcx: lifetime>) {
     type PointerTag = ();
     type ExtraFnVal = !;
 
-    type MemoryKind = !;
-    type MemoryMap = rustc_data_structures::fx::FxHashMap<AllocId, (MemoryKind<!>, Allocation)>;
-    const GLOBAL_KIND: Option<!> = None; // no copying of globals from `tcx` to machine memory
+    type MemoryMap =
+        rustc_data_structures::fx::FxHashMap<AllocId, (MemoryKind<Self::MemoryKind>, Allocation)>;
+    const GLOBAL_KIND: Option<Self::MemoryKind> = None; // no copying of globals from `tcx` to machine memory
 
     type AllocExtra = ();
     type FrameExtra = ();
@@ -407,7 +407,7 @@ pub macro compile_time_machine(<$mir: lifetime, $tcx: lifetime>) {
         _memory_extra: &Self::MemoryExtra,
         _id: AllocId,
         alloc: Cow<'b, Allocation>,
-        _kind: Option<MemoryKind<!>>,
+        _kind: Option<MemoryKind<Self::MemoryKind>>,
     ) -> (Cow<'b, Allocation<Self::PointerTag>>, Self::PointerTag) {
         // We do not use a tag so we can just cheaply forward the allocation
         (alloc, ())

compiler/rustc_mir/src/interpret/memory.rs

@@ -27,9 +27,6 @@ use crate::util::pretty;
 pub enum MemoryKind<T> {
     /// Stack memory. Error if deallocated except during a stack pop.
     Stack,
-    /// Heap memory.
-    /// FIXME: this variant should be in const_eval
-    ConstHeap,
     /// Memory backing vtables. Error if ever deallocated.
     Vtable,
     /// Memory allocated by `caller_location` intrinsic. Error if ever deallocated.
@@ -43,7 +40,6 @@ impl<T: MayLeak> MayLeak for MemoryKind<T> {
     fn may_leak(self) -> bool {
         match self {
             MemoryKind::Stack => false,
-            MemoryKind::ConstHeap => false,
             MemoryKind::Vtable => true,
             MemoryKind::CallerLocation => true,
             MemoryKind::Machine(k) => k.may_leak(),
@@ -55,7 +51,6 @@ impl<T: fmt::Display> fmt::Display for MemoryKind<T> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             MemoryKind::Stack => write!(f, "stack variable"),
-            MemoryKind::ConstHeap => write!(f, "heap allocation"),
             MemoryKind::Vtable => write!(f, "vtable"),
             MemoryKind::CallerLocation => write!(f, "caller location"),
             MemoryKind::Machine(m) => write!(f, "{}", m),

compiler/rustc_mir/src/transform/const_prop.rs

@@ -180,6 +180,8 @@ impl<'mir, 'tcx> ConstPropMachine<'mir, 'tcx> {
 impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for ConstPropMachine<'mir, 'tcx> {
     compile_time_machine!(<'mir, 'tcx>);
 
+    type MemoryKind = !;
+
     type MemoryExtra = ();
 
     fn find_mir_or_eval_fn(