From 32662e9fc88527cdc78fe87c4fe220904169cefe Mon Sep 17 00:00:00 2001
From: playX18 <adel.prokurov281@outlook.com>
Date: Sat, 15 Feb 2025 19:55:06 +0700
Subject: [PATCH] add VM::ALWAYS_TRACE

---
 vmkit/src/lib.rs         | 5 +++++
 vmkit/src/mm/scanning.rs | 3 +++
 2 files changed, 8 insertions(+)

diff --git a/vmkit/src/lib.rs b/vmkit/src/lib.rs
index 7248887..8ab3633 100644
--- a/vmkit/src/lib.rs
+++ b/vmkit/src/lib.rs
@@ -29,6 +29,11 @@ pub trait VirtualMachine: Sized + 'static + Send + Sync {
     type Slot: SlotExtra;
     type MemorySlice: MemorySlice<SlotType = Self::Slot>;
 
+
+    /// Should we always trace objects? If `true` then `support_slot_enqueing` will always return 
+    /// false to MMTk and we will always work through `ObjectTracer` to trace objects.
+    const ALWAYS_TRACE: bool = false;
+
     /*#[cfg(feature = "address_based_hashing")]
     const HASH_STATE_SPEC: VMLocalHashStateSpec = VMLocalHashStateSpec::in_header(61);*/
     /// 1-word local metadata for spaces that may copy objects.
diff --git a/vmkit/src/mm/scanning.rs b/vmkit/src/mm/scanning.rs
index 83678cf..c5739ef 100644
--- a/vmkit/src/mm/scanning.rs
+++ b/vmkit/src/mm/scanning.rs
@@ -124,6 +124,9 @@ impl<VM: VirtualMachine> Scanning<MemoryManager<VM>> for VMKitScanning<VM> {
         _tls: mmtk::util::VMWorkerThread,
         object: mmtk::util::ObjectReference,
     ) -> bool {
+        if VM::ALWAYS_TRACE {
+            return true;
+        }
         let object = VMKitObject::from(object);
         let metadata = object.header::<VM>().metadata();