Add marking functions for Julia objects.

src/julia_gc.c

@@ -30,6 +30,7 @@
 
 #include "julia.h"
 #include "julia_gcext.h"
+#include "julia_gc.h"
 
 
 /****************************************************************************
@@ -483,6 +484,31 @@ static inline int JMark(void * obj)
     return jl_gc_mark_queue_obj(JuliaTLS, (jl_value_t *)obj);
 }
 
+void MarkJuliaObjSafe(void * obj)
+{
+    if (!obj)
+        return;
+    // Validate that `obj` is still allocated and not on a
+    // free list already. We verify this by checking that the
+    // type is a pool object of type `jl_datatype_type`.
+    jl_value_t *ty = jl_typeof(obj);
+    if (jl_gc_internal_obj_base_ptr(ty) != ty)
+        return;
+    if (!jl_typeis(ty, jl_datatype_type))
+        return;
+    if (jl_gc_mark_queue_obj(JuliaTLS, (jl_value_t *)obj))
+        YoungRef++;
+}
+
+
+void MarkJuliaObj(void * obj)
+{
+    if (!obj)
+        return;
+    if (JMark(obj))
+        YoungRef++;
+}
+
 
 // Overview of conservative stack scanning
 //

src/julia_gc.h

@@ -0,0 +1,36 @@
+/****************************************************************************
+**
+**  This file is part of GAP, a system for computational discrete algebra.
+**
+**  Copyright of GAP belongs to its developers, whose names are too numerous
+**  to list here. Please refer to the COPYRIGHT file for details.
+**
+**  SPDX-License-Identifier: GPL-2.0-or-later
+**
+**  This file declares functions of the Julia GC interface.
+*/
+
+#ifndef GAP_JULIA_GC_H
+#define GAP_JULIA_GC_H
+
+/****************************************************************************
+**
+*F  MarkJuliaObj(<obj>) . . . . . . . . . . . . . . . . . . mark Julia object
+**
+**  'MarkJuliaObjSafe' marks a Julia object; the argument can be NULL.
+*/
+
+void MarkJuliaObj(void * obj);
+
+/****************************************************************************
+**
+*F  MarkJuliaObjSafe(<obj>) . . . . . . . . . . . . . . . . mark Julia object
+**
+**  'MarkJuliaObjSafe' marks a Julia object; the argument may be NULL.
+**  Extra validation steps are performed to determine whether <obj> is
+**  a valid Julia object. If not, it is silently ignored.
+*/
+
+void MarkJuliaObjSafe(void * obj);
+
+#endif