py/objtuple: Make mp_obj_tuple_get an inline function.

This can be done now that it's declared in `py/objtuple.h`, where the
`mp_obj_tuple` struct is defined.

This allows much better code generation for users of `mp_obj_tuple_get()`
where the caller uses len/items immediately (which is most uses), because
the compiler no longer needs to allocate the return values on the stack.

Changes code size by -36 bytes on bare-arm and -56 bytes on stm32.

Signed-off-by: Damien George <damien@micropython.org>

Author: dpgeorge

py/objtuple.c

@@ -251,13 +251,6 @@ mp_obj_t mp_obj_new_tuple(size_t n, const mp_obj_t *items) {
     return MP_OBJ_FROM_PTR(o);
 }
 
-void mp_obj_tuple_get(mp_obj_t self_in, size_t *len, mp_obj_t **items) {
-    assert(mp_obj_is_tuple_compatible(self_in));
-    mp_obj_tuple_t *self = MP_OBJ_TO_PTR(self_in);
-    *len = self->len;
-    *items = &self->items[0];
-}
-
 void mp_obj_tuple_del(mp_obj_t self_in) {
     assert(mp_obj_is_type(self_in, &mp_type_tuple));
     mp_obj_tuple_t *self = MP_OBJ_TO_PTR(self_in);

py/objtuple.h

@@ -28,6 +28,9 @@
 
 #include "py/obj.h"
 
+// type check is done on getiter method to allow tuple, namedtuple, attrtuple
+#define mp_obj_is_tuple_compatible(o) (MP_OBJ_TYPE_GET_SLOT_OR_NULL(mp_obj_get_type(o), iter) == mp_obj_tuple_getiter)
+
 typedef struct _mp_obj_tuple_t {
     mp_obj_base_t base;
     size_t len;
@@ -45,7 +48,14 @@ mp_obj_t mp_obj_tuple_unary_op(mp_unary_op_t op, mp_obj_t self_in);
 mp_obj_t mp_obj_tuple_binary_op(mp_binary_op_t op, mp_obj_t lhs, mp_obj_t rhs);
 mp_obj_t mp_obj_tuple_subscr(mp_obj_t base, mp_obj_t index, mp_obj_t value);
 mp_obj_t mp_obj_tuple_getiter(mp_obj_t o_in, mp_obj_iter_buf_t *iter_buf);
-void mp_obj_tuple_get(mp_obj_t self_in, size_t *len, mp_obj_t **items);
+
+static inline void mp_obj_tuple_get(mp_obj_t self_in, size_t *len, mp_obj_t **items) {
+    assert(mp_obj_is_tuple_compatible(self_in));
+    mp_obj_tuple_t *self = (mp_obj_tuple_t *)MP_OBJ_TO_PTR(self_in);
+    *len = self->len;
+    *items = &self->items[0];
+}
+
 void mp_obj_tuple_del(mp_obj_t self_in);
 
 extern const mp_obj_type_t mp_type_attrtuple;
@@ -63,7 +73,4 @@ void mp_obj_attrtuple_print_helper(const mp_print_t *print, const qstr *fields,
 
 mp_obj_t mp_obj_new_attrtuple(const qstr *fields, size_t n, const mp_obj_t *items);
 
-// type check is done on getiter method to allow tuple, namedtuple, attrtuple
-#define mp_obj_is_tuple_compatible(o) (MP_OBJ_TYPE_GET_SLOT_OR_NULL(mp_obj_get_type(o), iter) == mp_obj_tuple_getiter)
-
 #endif // MICROPY_INCLUDED_PY_OBJTUPLE_H