From 04edf3d9939d08f4e724cb91b9be374032cb662e Mon Sep 17 00:00:00 2001
From: Benoit Daloze <eregontp@gmail.com>
Date: Tue, 16 Dec 2025 13:02:33 +0100
Subject: [PATCH] ZJIT: Add a VALUE#write_barrier helper method to deduplicate
 logic

---
 zjit/src/cruby.rs   |  8 ++++++++
 zjit/src/gc.rs      |  4 +---
 zjit/src/profile.rs | 12 +++---------
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/zjit/src/cruby.rs b/zjit/src/cruby.rs
index 2bd44d2144..68b6810125 100644
--- a/zjit/src/cruby.rs
+++ b/zjit/src/cruby.rs
@@ -681,6 +681,14 @@ impl VALUE {
         let k: isize = item.wrapping_add(item.wrapping_add(1));
         VALUE(k as usize)
     }
+
+    /// Call the write barrier after separately writing val to self.
+    pub fn write_barrier(self, val: VALUE) {
+        // rb_gc_writebarrier() asserts it is not called with a special constant
+        if !val.special_const_p() {
+            unsafe { rb_gc_writebarrier(self, val) };
+        }
+    }
 }
 
 pub type IseqParameters = rb_iseq_constant_body_rb_iseq_parameters;
diff --git a/zjit/src/gc.rs b/zjit/src/gc.rs
index 0d2e1350a7..40230ccc8d 100644
--- a/zjit/src/gc.rs
+++ b/zjit/src/gc.rs
@@ -183,9 +183,7 @@ pub fn append_gc_offsets(iseq: IseqPtr, mut version: IseqVersionRef, offsets: &V
         let value_ptr = value_ptr as *const VALUE;
         unsafe {
             let object = value_ptr.read_unaligned();
-            if !object.special_const_p() {
-                rb_gc_writebarrier(iseq.into(), object);
-            }
+            VALUE::from(iseq).write_barrier(object);
         }
     }
 }
diff --git a/zjit/src/profile.rs b/zjit/src/profile.rs
index a4b893b2d7..867d97641b 100644
--- a/zjit/src/profile.rs
+++ b/zjit/src/profile.rs
@@ -124,9 +124,7 @@ fn profile_operands(profiler: &mut Profiler, profile: &mut IseqProfile, n: usize
         // TODO(max): Handle GC-hidden classes like Array, Hash, etc and make them look normal or
         // drop them or something
         let ty = ProfiledType::new(obj);
-        if !ty.class().special_const_p() {
-            unsafe { rb_gc_writebarrier(profiler.iseq.into(), ty.class()) };
-        }
+        VALUE::from(profiler.iseq).write_barrier(ty.class());
         profile_type.observe(ty);
     }
 }
@@ -140,9 +138,7 @@ fn profile_self(profiler: &mut Profiler, profile: &mut IseqProfile) {
     // TODO(max): Handle GC-hidden classes like Array, Hash, etc and make them look normal or
     // drop them or something
     let ty = ProfiledType::new(obj);
-    if !ty.class().special_const_p() {
-        unsafe { rb_gc_writebarrier(profiler.iseq.into(), ty.class()) };
-    }
+    VALUE::from(profiler.iseq).write_barrier(ty.class());
     types[0].observe(ty);
 }
 
@@ -153,9 +149,7 @@ fn profile_block_handler(profiler: &mut Profiler, profile: &mut IseqProfile) {
     }
     let obj = profiler.peek_at_block_handler();
     let ty = ProfiledType::object(obj);
-    if !ty.class().special_const_p() {
-        unsafe { rb_gc_writebarrier(profiler.iseq.into(), ty.class()) };
-    }
+    VALUE::from(profiler.iseq).write_barrier(ty.class());
     types[0].observe(ty);
 }