py: Store bytecode arg names in bytecode (were in own array).

This saves a lot of RAM for 2 reasons:

1. For functions that don't have default values, var args or var kw
args (which is a large number of functions in the general case), the
mp_obj_fun_bc_t type now fits in 1 GC block (previously needed 2 because
of the extra pointer to point to the arg_names array).  So this saves 16
bytes per function (32 bytes on 64-bit machines).

2. Combining separate memory regions generally saves RAM because the
unused bytes at the end of the GC block are saved for 1 of the blocks
(since that block doesn't exist on its own anymore).  So generally this
saves 8 bytes per function.

Tested by importing lots of modules:

- 64-bit Linux gave about an 8% RAM saving for 86k of used RAM.
- pyboard gave about a 6% RAM saving for 31k of used RAM.

1 files changed, 1 insertions, 2 deletions

diff --git a/py/emitglue.h b/py/emitglue.h
index 91d5285ad..fd55af26a 100644
--- a/py/emitglue.h
+++ b/py/emitglue.h
@@ -40,7 +40,6 @@ typedef struct _mp_raw_code_t {
     mp_uint_t scope_flags : 7;
     mp_uint_t n_pos_args : 11;
     mp_uint_t n_kwonly_args : 11;
-    qstr *arg_names;
     union {
         struct {
             byte *code;
@@ -55,7 +54,7 @@ typedef struct _mp_raw_code_t {
 
 mp_raw_code_t *mp_emit_glue_new_raw_code(void);
 
-void mp_emit_glue_assign_bytecode(mp_raw_code_t *rc, byte *code, mp_uint_t len, mp_uint_t n_pos_args, mp_uint_t n_kwonly_args, qstr *arg_names, mp_uint_t scope_flags);
+void mp_emit_glue_assign_bytecode(mp_raw_code_t *rc, byte *code, mp_uint_t len, mp_uint_t n_pos_args, mp_uint_t n_kwonly_args, mp_uint_t scope_flags);
 void mp_emit_glue_assign_native(mp_raw_code_t *rc, mp_raw_code_kind_t kind, void *fun_data, mp_uint_t fun_len, mp_uint_t n_args, mp_uint_t type_sig);
 
 mp_obj_t mp_make_function_from_raw_code(mp_raw_code_t *rc, mp_obj_t def_args, mp_obj_t def_kw_args);