From f5dae8e73c3449d76311781ba86aa82034fb5296 Mon Sep 17 00:00:00 2001
From: Ben Kimock <kimockb@gmail.com>
Date: Sun, 19 Nov 2023 16:17:48 -0500
Subject: [PATCH] Miri: GC the dead_alloc_map too
---
compiler/rustc_const_eval/src/interpret/memory.rs | 11 +++++++++++
src/tools/miri/src/provenance_gc.rs | 3 ++-
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs
index d5b165a7415..1c1fd2a71ba 100644
--- a/compiler/rustc_const_eval/src/interpret/memory.rs
+++ b/compiler/rustc_const_eval/src/interpret/memory.rs
@@ -501,6 +501,17 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
}
}
+impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
+ /// This function is used by Miri's provenance GC to remove unreachable entries from the dead_alloc_map.
+ pub fn remove_unreachable_allocs(&mut self, reachable_allocs: &FxHashSet<AllocId>) {
+ // Unlike all the other GC helpers where we check if an `AllocId` is found in the interpreter or
+ // is live, here all the IDs in the map are for dead allocations so we don't
+ // need to check for liveness.
+ #[allow(rustc::potential_query_instability)] // Only used from Miri, not queries.
+ self.memory.dead_alloc_map.retain(|id, _| reachable_allocs.contains(id));
+ }
+}
+
/// Allocation accessors
impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
/// Helper function to obtain a global (tcx) allocation.
diff --git a/src/tools/miri/src/provenance_gc.rs b/src/tools/miri/src/provenance_gc.rs
index eac4aad27a0..ef6d49f041f 100644
--- a/src/tools/miri/src/provenance_gc.rs
+++ b/src/tools/miri/src/provenance_gc.rs
@@ -195,7 +195,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: MiriInterpCxExt<'mir, 'tcx> {
}
fn remove_unreachable_allocs(&mut self, allocs: FxHashSet<AllocId>) {
- let this = self.eval_context_ref();
+ let this = self.eval_context_mut();
let allocs = LiveAllocs {
ecx: this,
collected: allocs,
@@ -205,5 +205,6 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: MiriInterpCxExt<'mir, 'tcx> {
if let Some(borrow_tracker) = &this.machine.borrow_tracker {
borrow_tracker.borrow_mut().remove_unreachable_allocs(&allocs);
}
+ this.remove_unreachable_allocs(&allocs.collected);
}
}