objclosure: Store reference to entire closed variables tuple.

Avoids pointer-to-field garbage collection issue. Fixes #510.

py/objclosure.c

@@ -5,41 +5,60 @@
 #include "mpconfig.h"
 #include "qstr.h"
 #include "obj.h"
+#include "objtuple.h"
 #include "runtime.h"
 
 typedef struct _mp_obj_closure_t {
     mp_obj_base_t base;
     mp_obj_t fun;
-    uint n_closed;
-    mp_obj_t *closed;
+    mp_obj_tuple_t *closure_tuple;
 } mp_obj_closure_t;
 
 mp_obj_t closure_call(mp_obj_t self_in, uint n_args, uint n_kw, const mp_obj_t *args) {
     mp_obj_closure_t *self = self_in;
+    mp_obj_tuple_t *t = self->closure_tuple;
 
     // need to concatenate closed-over-vars and args
 
-    int n_total = self->n_closed + n_args + 2 * n_kw;
+    int n_total = t->len + n_args + 2 * n_kw;
     if (n_total <= 5) {
         // use stack to allocate temporary args array
         mp_obj_t args2[5];
-        memcpy(args2, self->closed, self->n_closed * sizeof(mp_obj_t));
-        memcpy(args2 + self->n_closed, args, (n_args + 2 * n_kw) * sizeof(mp_obj_t));
-        return mp_call_function_n_kw(self->fun, self->n_closed + n_args, n_kw, args2);
+        memcpy(args2, t->items, t->len * sizeof(mp_obj_t));
+        memcpy(args2 + t->len, args, (n_args + 2 * n_kw) * sizeof(mp_obj_t));
+        return mp_call_function_n_kw(self->fun, t->len + n_args, n_kw, args2);
     } else {
         // use heap to allocate temporary args array
         mp_obj_t *args2 = m_new(mp_obj_t, n_total);
-        memcpy(args2, self->closed, self->n_closed * sizeof(mp_obj_t));
-        memcpy(args2 + self->n_closed, args, (n_args + 2 * n_kw) * sizeof(mp_obj_t));
-        mp_obj_t res = mp_call_function_n_kw(self->fun, self->n_closed + n_args, n_kw, args2);
+        memcpy(args2, t->items, t->len * sizeof(mp_obj_t));
+        memcpy(args2 + t->len, args, (n_args + 2 * n_kw) * sizeof(mp_obj_t));
+        mp_obj_t res = mp_call_function_n_kw(self->fun, t->len + n_args, n_kw, args2);
         m_del(mp_obj_t, args2, n_total);
         return res;
     }
 }
 
+#if 0
+STATIC void closure_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t o_in, mp_print_kind_t kind) {
+    mp_obj_closure_t *o = o_in;
+    print(env, "<closure %p (closed: %p) ", o, o->closure_tuple);
+    mp_obj_tuple_t *t = o->closure_tuple;
+    for (int i = 0; i < t->len; i++) {
+        if (t->items[i] == MP_OBJ_NULL) {
+            print(env, "(nil)");
+        } else {
+            mp_obj_print_helper(print, env, t->items[i], PRINT_REPR);
+        }
+        print(env, " ");
+    }
+    print(env, ">");
+}
+#endif
+
 const mp_obj_type_t closure_type = {
     { &mp_type_type },
     .name = MP_QSTR_closure,
+    //.print = closure_print,
     .call = closure_call,
 };
 
@@ -47,6 +66,6 @@ mp_obj_t mp_obj_new_closure(mp_obj_t fun, mp_obj_t closure_tuple) {
     mp_obj_closure_t *o = m_new_obj(mp_obj_closure_t);
     o->base.type = &closure_type;
     o->fun = fun;
-    mp_obj_tuple_get(closure_tuple, &o->n_closed, &o->closed);
+    o->closure_tuple = closure_tuple;
     return o;
 }