From 40053354bd9a8d66116ff9bfdeff45f0311a9386 Mon Sep 17 00:00:00 2001
From: Peter Zhu <peter@peterzhu.ca>
Date: Sun, 17 May 2026 08:32:21 -0400
Subject: [PATCH] Move rb_gc_obj_suffix to gc.h

---
 gc/gc.h        | 24 ++++++++++++++++++++++++
 gc/mmtk/mmtk.c | 23 ++++-------------------
 2 files changed, 28 insertions(+), 19 deletions(-)

diff --git a/gc/gc.h b/gc/gc.h
index 2809c7a..05f7e87 100644
--- a/gc/gc.h
+++ b/gc/gc.h
@@ -10,9 +10,33 @@
  *             first introduced for [Feature #20470].
  */
 #include "ruby/ruby.h"
+#include "ruby/assert.h"
 
 #include "ruby/thread_native.h"
 
+#ifndef VM_CHECK_MODE
+# define VM_CHECK_MODE RUBY_DEBUG
+#endif
+
+// From ractor_core.h
+#ifndef RACTOR_CHECK_MODE
+# define RACTOR_CHECK_MODE (VM_CHECK_MODE || RUBY_DEBUG) && (SIZEOF_UINT64_T == SIZEOF_VALUE)
+#endif
+
+#if RACTOR_CHECK_MODE
+void rb_ractor_setup_belonging(VALUE obj);
+
+struct rb_gc_obj_suffix {
+    uint32_t _ractor_belonging_id;
+};
+
+# define RB_GC_OBJ_HAS_SUFFIX 1
+# define RB_GC_OBJ_SUFFIX_SIZE (sizeof(struct rb_gc_obj_suffix))
+#else
+# define RB_GC_OBJ_HAS_SUFFIX 0
+# define RB_GC_OBJ_SUFFIX_SIZE 0
+#endif
+
 struct rb_gc_vm_context {
     rb_nativethread_lock_t lock;
 
diff --git a/gc/mmtk/mmtk.c b/gc/mmtk/mmtk.c
index 143999c..24f0567 100644
--- a/gc/mmtk/mmtk.c
+++ b/gc/mmtk/mmtk.c
@@ -16,21 +16,6 @@
 #include <sys/sysctl.h>
 #endif
 
-#ifndef VM_CHECK_MODE
-# define VM_CHECK_MODE RUBY_DEBUG
-#endif
-
-// From ractor_core.h
-#ifndef RACTOR_CHECK_MODE
-# define RACTOR_CHECK_MODE (VM_CHECK_MODE || RUBY_DEBUG) && (SIZEOF_UINT64_T == SIZEOF_VALUE)
-#endif
-
-#if RACTOR_CHECK_MODE
-# define RVALUE_SUFFIX_SIZE sizeof(VALUE)
-#else
-# define RVALUE_SUFFIX_SIZE 0
-#endif
-
 struct objspace {
     bool measure_gc_time;
     bool gc_stress;
@@ -575,7 +560,7 @@ rb_gc_impl_objspace_alloc(void)
 {
     MMTk_Builder *builder = rb_mmtk_builder_init();
     MMTk_RubyBindingOptions binding_options = {
-        .suffix_size = RVALUE_SUFFIX_SIZE,
+        .suffix_size = RB_GC_OBJ_SUFFIX_SIZE,
     };
     mmtk_init_binding(builder, &binding_options, &ruby_upcalls);
 
@@ -913,8 +898,8 @@ rb_gc_impl_new_obj(void *objspace_ptr, void *cache_ptr, VALUE klass, VALUE flags
         mmtk_handle_user_collection_request(ractor_cache, false, false);
     }
 
-    // Layout: [hidden size header (sizeof(VALUE))][payload (alloc_size)][suffix (RVALUE_SUFFIX_SIZE)]
-    alloc_size += sizeof(VALUE) + RVALUE_SUFFIX_SIZE;
+    // Layout: [hidden size header (sizeof(VALUE))][payload (alloc_size)][suffix (RB_GC_OBJ_SUFFIX_SIZE)]
+    alloc_size += sizeof(VALUE) + RB_GC_OBJ_SUFFIX_SIZE;
 
     VALUE *alloc_obj = (VALUE *)rb_mmtk_alloc_fast_path(objspace, ractor_cache, alloc_size, MMTk_MIN_OBJ_ALIGN);
     if (!alloc_obj) {
@@ -922,7 +907,7 @@ rb_gc_impl_new_obj(void *objspace_ptr, void *cache_ptr, VALUE klass, VALUE flags
     }
 
     alloc_obj++;
-    alloc_obj[-1] = alloc_size - sizeof(VALUE) - RVALUE_SUFFIX_SIZE;
+    alloc_obj[-1] = alloc_size - sizeof(VALUE) - RB_GC_OBJ_SUFFIX_SIZE;
     alloc_obj[0] = flags;
     alloc_obj[1] = klass;