Move `DisambiguatorState` into `intern_const_alloc_recursive`

2 files changed, 28 insertions, 14 deletions

diff --git a/compiler/rustc_const_eval/src/interpret/intern.rs b/compiler/rustc_const_eval/src/interpret/intern.rs
index 47cc2d49fe2..1dd96297d1f 100644
--- a/compiler/rustc_const_eval/src/interpret/intern.rs
+++ b/compiler/rustc_const_eval/src/interpret/intern.rs
@@ -46,13 +46,12 @@ pub trait CompileTimeMachine<'tcx, T> = Machine<
 pub trait HasStaticRootDefId {
     /// Returns the `DefId` of the static item that is currently being evaluated.
     /// Used for interning to be able to handle nested allocations.
-    fn static_parent_and_disambiguator(&mut self) -> Option<(LocalDefId, &mut DisambiguatorState)>;
+    fn static_def_id(&self) -> Option<LocalDefId>;
 }
 
 impl HasStaticRootDefId for const_eval::CompileTimeMachine<'_> {
-    fn static_parent_and_disambiguator(&mut self) -> Option<(LocalDefId, &mut DisambiguatorState)> {
-        let (_, static_id, d) = self.static_root_ids.as_mut()?;
-        Some((*static_id, d))
+    fn static_def_id(&self) -> Option<LocalDefId> {
+        Some(self.static_root_ids?.1)
     }
 }
 
@@ -67,6 +66,7 @@ fn intern_shallow<'tcx, T, M: CompileTimeMachine<'tcx, T>>(
     ecx: &mut InterpCx<'tcx, M>,
     alloc_id: AllocId,
     mutability: Mutability,
+    disambiguator: Option<&mut DisambiguatorState>,
 ) -> Result<impl Iterator<Item = CtfeProvenance> + 'tcx, ()> {
     trace!("intern_shallow {:?}", alloc_id);
     // remove allocation
@@ -88,8 +88,14 @@ fn intern_shallow<'tcx, T, M: CompileTimeMachine<'tcx, T>>(
     }
     // link the alloc id to the actual allocation
     let alloc = ecx.tcx.mk_const_alloc(alloc);
-    if let Some((static_id, disambiguator)) = ecx.machine.static_parent_and_disambiguator() {
-        intern_as_new_static(ecx.tcx, static_id, alloc_id, alloc, disambiguator);
+    if let Some(static_id) = ecx.machine.static_def_id() {
+        intern_as_new_static(
+            ecx.tcx,
+            static_id,
+            alloc_id,
+            alloc,
+            disambiguator.expect("disambiguator needed"),
+        );
     } else {
         ecx.tcx.set_alloc_id_memory(alloc_id, alloc);
     }
@@ -105,6 +111,10 @@ fn intern_as_new_static<'tcx>(
     alloc: ConstAllocation<'tcx>,
     disambiguator: &mut DisambiguatorState,
 ) {
+    // `intern_const_alloc_recursive` is called once per static and it contains the `DisambiguatorState`.
+    //  The `<static_id>::{{nested}}` path is thus unique to `intern_const_alloc_recursive` and the
+    // `DisambiguatorState` ensures the generated path is unique for this call as we generate
+    // `<static_id>::{{nested#n}}` where `n` is the `n`th `intern_as_new_static` call.
     let feed = tcx.create_def(
         static_id,
         None,
@@ -158,6 +168,8 @@ pub fn intern_const_alloc_recursive<'tcx, M: CompileTimeMachine<'tcx, const_eval
     intern_kind: InternKind,
     ret: &MPlaceTy<'tcx>,
 ) -> Result<(), InternResult> {
+    let mut disambiguator = DisambiguatorState::new();
+
     // We are interning recursively, and for mutability we are distinguishing the "root" allocation
     // that we are starting in, and all other allocations that we are encountering recursively.
     let (base_mutability, inner_mutability, is_static) = match intern_kind {
@@ -201,7 +213,9 @@ pub fn intern_const_alloc_recursive<'tcx, M: CompileTimeMachine<'tcx, const_eval
         alloc.1.mutability = base_mutability;
         alloc.1.provenance().ptrs().iter().map(|&(_, prov)| prov).collect()
     } else {
-        intern_shallow(ecx, base_alloc_id, base_mutability).unwrap().collect()
+        intern_shallow(ecx, base_alloc_id, base_mutability, Some(&mut disambiguator))
+            .unwrap()
+            .collect()
     };
     // We need to distinguish "has just been interned" from "was already in `tcx`",
     // so we track this in a separate set.
@@ -295,7 +309,7 @@ pub fn intern_const_alloc_recursive<'tcx, M: CompileTimeMachine<'tcx, const_eval
         // okay with losing some potential for immutability here. This can anyway only affect
         // `static mut`.
         just_interned.insert(alloc_id);
-        match intern_shallow(ecx, alloc_id, inner_mutability) {
+        match intern_shallow(ecx, alloc_id, inner_mutability, Some(&mut disambiguator)) {
             Ok(nested) => todo.extend(nested),
             Err(()) => {
                 ecx.tcx.dcx().delayed_bug("found dangling pointer during const interning");
@@ -317,8 +331,9 @@ pub fn intern_const_alloc_for_constprop<'tcx, T, M: CompileTimeMachine<'tcx, T>>
         return interp_ok(());
     }
     // Move allocation to `tcx`.
-    if let Some(_) =
-        (intern_shallow(ecx, alloc_id, Mutability::Not).map_err(|()| err_ub!(DeadLocal))?).next()
+    if let Some(_) = intern_shallow(ecx, alloc_id, Mutability::Not, None)
+        .map_err(|()| err_ub!(DeadLocal))?
+        .next()
     {
         // We are not doing recursive interning, so we don't currently support provenance.
         // (If this assertion ever triggers, we should just implement a
@@ -344,7 +359,7 @@ impl<'tcx> InterpCx<'tcx, DummyMachine> {
         let dest = self.allocate(layout, MemoryKind::Stack)?;
         f(self, &dest.clone().into())?;
         let alloc_id = dest.ptr().provenance.unwrap().alloc_id(); // this was just allocated, it must have provenance
-        for prov in intern_shallow(self, alloc_id, Mutability::Not).unwrap() {
+        for prov in intern_shallow(self, alloc_id, Mutability::Not, None).unwrap() {
             // We are not doing recursive interning, so we don't currently support provenance.
             // (If this assertion ever triggers, we should just implement a
             // proper recursive interning loop -- or just call `intern_const_alloc_recursive`.
diff --git a/compiler/rustc_const_eval/src/interpret/util.rs b/compiler/rustc_const_eval/src/interpret/util.rs
index faaa2bd24bb..ba579e25f03 100644
--- a/compiler/rustc_const_eval/src/interpret/util.rs
+++ b/compiler/rustc_const_eval/src/interpret/util.rs
@@ -1,5 +1,4 @@
 use rustc_hir::def_id::LocalDefId;
-use rustc_hir::definitions::DisambiguatorState;
 use rustc_middle::mir;
 use rustc_middle::mir::interpret::{AllocInit, Allocation, InterpResult, Pointer};
 use rustc_middle::ty::layout::TyAndLayout;
@@ -41,8 +40,8 @@ pub(crate) fn create_static_alloc<'tcx>(
 ) -> InterpResult<'tcx, MPlaceTy<'tcx>> {
     let alloc = Allocation::try_new(layout.size, layout.align.abi, AllocInit::Uninit)?;
     let alloc_id = ecx.tcx.reserve_and_set_static_alloc(static_def_id.into());
-    assert!(ecx.machine.static_root_ids.is_none());
-    ecx.machine.static_root_ids = Some((alloc_id, static_def_id, DisambiguatorState::new()));
+    assert_eq!(ecx.machine.static_root_ids, None);
+    ecx.machine.static_root_ids = Some((alloc_id, static_def_id));
     assert!(ecx.memory.alloc_map.insert(alloc_id, (MemoryKind::Stack, alloc)).is_none());
     interp_ok(ecx.ptr_to_mplace(Pointer::from(alloc_id).into(), layout))
 }