py: Combine duplicated code that converts members from a lookup.
Despite initial guess, this code factoring does not hamper performance.
In fact it seems to improve speed by a little: running pystone(1.2) on
pyboard (which gives a very stable result) this patch takes pystones
from 1729.51 up to 1742.16. Also, pystones on x64 increase by around
the same proportion (but it's much noisier).
Taking a look at the generated machine code, stack usage with this patch
is unchanged, and call is tail-optimised with all arguments in
registers. Code size decreases by about 50 bytes on Thumb2 archs.
diff --git a/py/runtime.h b/py/runtime.h
index e091624..bead028 100644
--- a/py/runtime.h
+++ b/py/runtime.h
@@ -101,6 +101,7 @@
void mp_unpack_ex(mp_obj_t seq, mp_uint_t num, mp_obj_t *items);
mp_obj_t mp_store_map(mp_obj_t map, mp_obj_t key, mp_obj_t value);
mp_obj_t mp_load_attr(mp_obj_t base, qstr attr);
+void mp_convert_member_lookup(mp_obj_t obj, const mp_obj_type_t *type, mp_obj_t member, mp_obj_t *dest);
void mp_load_method(mp_obj_t base, qstr attr, mp_obj_t *dest);
void mp_load_method_maybe(mp_obj_t base, qstr attr, mp_obj_t *dest);
void mp_store_attr(mp_obj_t base, qstr attr, mp_obj_t val);