From 6e8ad619249fb9c2783fff2024ef4846dc4cdcde Mon Sep 17 00:00:00 2001
From: Peter Zhu <peter@peterzhu.ca>
Date: Wed, 28 Oct 2026 11:06:00 +0900
Subject: [PATCH] Register pinned root objects in PinningRegistry

We need to register objects pinned from the root in PinningRegistry for
rb_gc_impl_pinned_p to work properly.
---
 gc/mmtk/src/pinning_registry.rs | 7 +++++++
 gc/mmtk/src/scanning.rs         | 5 +++++
 2 files changed, 12 insertions(+)

diff --git a/gc/mmtk/src/pinning_registry.rs b/gc/mmtk/src/pinning_registry.rs
index 7b295d4..bd51148 100644
--- a/gc/mmtk/src/pinning_registry.rs
+++ b/gc/mmtk/src/pinning_registry.rs
@@ -30,6 +30,13 @@ impl PinningRegistry {
         pinning_objs.push(object);
     }
 
+    pub fn register_pinned_obj(&self, object: ObjectReference) {
+        if memory_manager::pin_object(object) {
+            let mut pinned_objs = self.pinned_objs.lock().unwrap();
+            pinned_objs.push(object);
+        }
+    }
+
     pub fn pin_children(&self, tls: VMWorkerThread) {
         if !crate::mmtk().get_plan().current_gc_may_move_object() {
             log::debug!("The current GC is non-moving, skipping pinning children.");
diff --git a/gc/mmtk/src/scanning.rs b/gc/mmtk/src/scanning.rs
index 7b59483..37ecefc 100644
--- a/gc/mmtk/src/scanning.rs
+++ b/gc/mmtk/src/scanning.rs
@@ -194,6 +194,11 @@ impl VMScanning {
                 mmtk::memory_manager::is_mmtk_object(object.to_raw_address()).is_some(),
                 "Root does not point to MMTk object.  object: {object}"
             );
+            if pin && crate::mmtk().get_plan().current_gc_may_move_object() {
+                crate::binding()
+                    .pinning_registry
+                    .register_pinned_obj(object);
+            }
             buffer.push(object);
             if buffer.len() >= Self::OBJECT_BUFFER_SIZE {
                 factory.create_process_pinning_roots_work(std::mem::take(&mut buffer));