Remove mp_obj_type_t.methods entry and use .locals_dict instead.

Originally, .methods was used for methods in a ROM class, and
locals_dict for methods in a user-created class.  That distinction is
unnecessary, and we can use locals_dict for ROM classes now that we have
ROMable maps.

This removes an entry in the bloated mp_obj_type_t struct, saving a word
for each ROM object and each RAM object.  ROM objects that have a
methods table (now a locals_dict) need an extra word in total (removed
the methods pointer (1 word), no longer need the sentinel (2 words), but
now need an mp_obj_dict_t wrapper (4 words)).  But RAM objects save a
word because they never used the methods entry.

Overall the ROM usage is down by a few hundred bytes, and RAM usage is
down 1 word per user-defined type/class.

There is less code (no need to check 2 tables), and now consistent with
the way ROM modules have their tables initialised.

Efficiency is very close to equivaluent.

1 files changed, 15 insertions, 2 deletions

diff --git a/py/obj.h b/py/obj.h
index 1c22e956b8..12f8cabf48 100644
--- a/py/obj.h
+++ b/py/obj.h
@@ -59,6 +59,21 @@ typedef struct _mp_obj_base_t mp_obj_base_t;
 #define MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(obj_name, n_args_min, n_args_max, fun_name) MP_DEFINE_CONST_FUN_OBJ_VOID_PTR(obj_name, false, n_args_min, n_args_max, (mp_fun_var_t)fun_name)
 #define MP_DEFINE_CONST_FUN_OBJ_KW(obj_name, n_args_min, fun_name) MP_DEFINE_CONST_FUN_OBJ_VOID_PTR(obj_name, true, n_args_min, MP_OBJ_FUN_ARGS_MAX, (mp_fun_kw_t)fun_name)
 
+// This macro is used to define constant dict objects
+// You can put "static" in front of the definition to make it local
+
+#define MP_DEFINE_CONST_DICT(dict_name, table_name) \
+    const mp_obj_dict_t dict_name = { \
+        .base = {&dict_type}, \
+        .map = { \
+            .all_keys_are_qstrs = 1, \
+            .table_is_fixed_array = 1, \
+            .used = sizeof(table_name) / sizeof(mp_map_elem_t), \
+            .alloc = sizeof(table_name) / sizeof(mp_map_elem_t), \
+            .table = (mp_map_elem_t*)table_name, \
+        }, \
+    }
+
 // These macros are used to declare and define constant staticmethond and classmethod objects
 // You can put "static" in front of the definitions to make them local
 
@@ -160,8 +175,6 @@ struct _mp_obj_type_t {
     mp_buffer_p_t buffer_p;
     mp_stream_p_t stream_p;
 
-    const mp_method_t *methods;
-
     // these are for dynamically created types (classes)
     mp_obj_t bases_tuple;
     mp_obj_t locals_dict;