Implement unmanaged_size for VMArray REPR.

Author: jnthn

src/6model/reprs/MVMArray.c

@@ -1194,6 +1194,13 @@ static void spesh(MVMThreadContext *tc, MVMSTable *st, MVMSpeshGraph *g, MVMSpes
     }
 }
 
+/* Calculates the non-GC-managed memory we hold on to. */
+MVMuint64 unmanaged_size(MVMThreadContext *tc, MVMSTable *st, void *data) {
+    MVMArrayREPRData *repr_data = (MVMArrayREPRData *) st->REPR_data;
+    MVMArrayBody     *body      = (MVMArrayBody *)data;
+    return body->ssize * repr_data->elem_size;
+}
+
 /* Initializes the representation. */
 const MVMREPROps * MVMArray_initialize(MVMThreadContext *tc) {
     return &this_repr;
@@ -1240,5 +1247,5 @@ static const MVMREPROps this_repr = {
     "VMArray", /* name */
     MVM_REPR_ID_MVMArray,
     0, /* refs_frames */
-    NULL, /* unmanaged_size */
+    unmanaged_size,
 };