/* Functions for if the write barriers are hit. */

MVM_PUBLIC void MVM_gc_write_barrier_hit(MVMThreadContext *tc, MVMCollectable *update_root);

/* Ensures that if a generation 2 object comes to hold a reference to a

 * nursery object, then the generation 2 object becomes an inter-generational

 * root. */

MVM_STATIC_INLINE void MVM_gc_write_barrier(MVMThreadContext *tc, MVMCollectable *update_root, const MVMCollectable *referenced) {

    if (((update_root->flags & MVM_CF_SECOND_GEN) && referenced && !(referenced->flags & MVM_CF_SECOND_GEN)))

        MVM_gc_write_barrier_hit(tc, update_root);

}

/* Does an assignment, but makes sure the write barrier MVM_WB is applied

 * first. Takes the root object, the address within it we're writing to, and

 * the thing we're writing. Note that update_addr is not involved in the

 * write barrier. */

#if MVM_GC_DEBUG

#define MVM_ASSIGN_REF(tc, update_root, update_addr, referenced) \

    { \

        void *_r = referenced; \

        if (_r && ((MVMCollectable *)_r)->owner == 0) \

            MVM_panic(1, "Invalid assignment (maybe of heap frame to stack frame?)"); \

        MVM_ASSERT_NOT_FROMSPACE(tc, _r); \

        MVM_gc_write_barrier(tc, update_root, (MVMCollectable *)_r); \

        update_addr = _r; \

    }

#else

#define MVM_ASSIGN_REF(tc, update_root, update_addr, referenced) \

    { \

        void *_r = referenced; \

        MVM_gc_write_barrier(tc, update_root, (MVMCollectable *)_r); \

        update_addr = _r; \

    }

#endif