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, 14 insertions, 11 deletions

diff --git a/stm/adc.c b/stm/adc.c
index 0706787579..acdaa97dae 100644
--- a/stm/adc.c
+++ b/stm/adc.c
@@ -6,6 +6,7 @@
 #include "mpconfig.h"
 #include "qstr.h"
 #include "obj.h"
+#include "map.h"
 #include "adc.h"
 
 /* ADC defintions */
@@ -323,19 +324,20 @@ static MP_DEFINE_CONST_FUN_OBJ_1(adc_all_read_core_temp_obj, adc_all_read_core_t
 static MP_DEFINE_CONST_FUN_OBJ_1(adc_all_read_core_vbat_obj, adc_all_read_core_vbat);
 static MP_DEFINE_CONST_FUN_OBJ_1(adc_all_read_core_vref_obj, adc_all_read_core_vref);
 
-static const mp_method_t adc_all_methods[] = {
-    { MP_QSTR_read_channel,   &adc_all_read_channel_obj},
-    { MP_QSTR_read_core_temp, &adc_all_read_core_temp_obj},
-    { MP_QSTR_read_core_vbat, &adc_all_read_core_vbat_obj},
-    { MP_QSTR_read_core_vref, &adc_all_read_core_vref_obj},
-    { MP_QSTR_NULL, NULL },
+STATIC const mp_map_elem_t adc_all_locals_dict_table[] = {
+    { MP_OBJ_NEW_QSTR(MP_QSTR_read_channel), (mp_obj_t)  &adc_all_read_channel_obj},
+    { MP_OBJ_NEW_QSTR(MP_QSTR_read_core_temp), (mp_obj_t)&adc_all_read_core_temp_obj},
+    { MP_OBJ_NEW_QSTR(MP_QSTR_read_core_vbat), (mp_obj_t)&adc_all_read_core_vbat_obj},
+    { MP_OBJ_NEW_QSTR(MP_QSTR_read_core_vref), (mp_obj_t)&adc_all_read_core_vref_obj},
 };
 
+STATIC MP_DEFINE_CONST_DICT(adc_all_locals_dict, adc_all_locals_dict_table);
+
 static const mp_obj_type_t adc_all_type = {
     { &mp_type_type },
     .name = MP_QSTR_ADC,
     .print = adc_all_print,
-    .methods = adc_all_methods,
+    .locals_dict = (mp_obj_t)&adc_all_locals_dict,
 };
 
 mp_obj_t pyb_ADC_all(mp_obj_t resolution) {
@@ -380,16 +382,17 @@ static mp_obj_t adc_read(mp_obj_t self_in) {
 
 static MP_DEFINE_CONST_FUN_OBJ_1(adc_read_obj, adc_read);
 
-static const mp_method_t adc_methods[] = {
-    { MP_QSTR_read, &adc_read_obj},
-    { MP_QSTR_NULL, NULL },
+STATIC const mp_map_elem_t adc_locals_dict_table[] = {
+    { MP_OBJ_NEW_QSTR(MP_QSTR_read), (mp_obj_t)&adc_read_obj},
 };
 
+STATIC MP_DEFINE_CONST_DICT(adc_locals_dict, adc_locals_dict_table);
+
 static const mp_obj_type_t adc_type = {
     { &mp_type_type },
     .name = MP_QSTR_ADC,
     .print = adc_print,
-    .methods = adc_methods,
+    .locals_dict = (mp_obj_t)&adc_locals_dict,
 };
 
 mp_obj_t pyb_ADC(mp_obj_t pin_name_obj) {