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, 11 insertions, 9 deletions

diff --git a/unix/file.c b/unix/file.c
index d711ace4f..f037b6f7e 100644
--- a/unix/file.c
+++ b/unix/file.c
@@ -9,6 +9,7 @@
 #include "mpconfig.h"
 #include "qstr.h"
 #include "obj.h"
+#include "map.h"
 #include "runtime.h"
 #include "stream.h"
 
@@ -105,16 +106,17 @@ static mp_obj_t fdfile_make_new(mp_obj_t type_in, uint n_args, uint n_kw, const
     return fdfile_new(fd);
 }
 
-static const mp_method_t rawfile_type_methods[] = {
-    { MP_QSTR_fileno, &fdfile_fileno_obj },
-    { MP_QSTR_read, &mp_stream_read_obj },
-    { MP_QSTR_readall, &mp_stream_readall_obj },
-    { MP_QSTR_readline, &mp_stream_unbuffered_readline_obj},
-    { MP_QSTR_write, &mp_stream_write_obj },
-    { MP_QSTR_close, &fdfile_close_obj },
-    { MP_QSTR_NULL, NULL },
+STATIC const mp_map_elem_t rawfile_locals_dict_table[] = {
+    { MP_OBJ_NEW_QSTR(MP_QSTR_fileno), (mp_obj_t)&fdfile_fileno_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_read), (mp_obj_t)&mp_stream_read_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_readall), (mp_obj_t)&mp_stream_readall_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_readline), (mp_obj_t)&mp_stream_unbuffered_readline_obj},
+    { MP_OBJ_NEW_QSTR(MP_QSTR_write), (mp_obj_t)&mp_stream_write_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_close), (mp_obj_t)&fdfile_close_obj },
 };
 
+STATIC MP_DEFINE_CONST_DICT(rawfile_locals_dict, rawfile_locals_dict_table);
+
 static const mp_obj_type_t rawfile_type = {
     { &mp_type_type },
     .name = MP_QSTR_io_dot_FileIO,
@@ -126,7 +128,7 @@ static const mp_obj_type_t rawfile_type = {
         .read = fdfile_read,
         .write = fdfile_write,
     },
-    .methods = rawfile_type_methods,
+    .locals_dict = (mp_obj_t)&rawfile_locals_dict,
 };
 
 // Factory function for I/O stream classes