py: Instead of having "debug on" var, have "optimization level" var.

This allows to have multiple "optimization" levels (CPython has two
(-OO removes docstrings), we can have more).

py/lexer.c

@@ -64,12 +64,7 @@ struct _mp_lexer_t {
     mp_token_t tok_cur;
 };
 
-// debug flag for __debug__ constant
+uint mp_optimise_value;
-STATIC mp_token_kind_t mp_debug_value;
-
-void mp_set_debug(bool value) {
-    mp_debug_value = value ? MP_TOKEN_KW_TRUE : MP_TOKEN_KW_FALSE;
-}
 
 // TODO replace with a call to a standard function
 bool str_strn_equal(const char *str, const char *strn, int len) {
@@ -703,7 +698,7 @@ STATIC void mp_lexer_next_token_into(mp_lexer_t *lex, mp_token_t *tok, bool firs
             if (str_strn_equal(tok_kw[i], tok->str, tok->len)) {
                 if (i == ARRAY_SIZE(tok_kw) - 1) {
                     // tok_kw[ARRAY_SIZE(tok_kw) - 1] == "__debug__"
-                    tok->kind = mp_debug_value;
+                    tok->kind = (mp_optimise_value == 0 ? MP_TOKEN_KW_TRUE : MP_TOKEN_KW_FALSE);
                 } else {
                     tok->kind = MP_TOKEN_KW_FALSE + i;
                 }

py/lexer.h

@@ -176,3 +176,5 @@ typedef enum {
 
 mp_import_stat_t mp_import_stat(const char *path);
 mp_lexer_t *mp_lexer_new_from_file(const char *filename);
+
+extern uint mp_optimise_value;

py/runtime.c

@@ -45,6 +45,7 @@
 #include "bc.h"
 #include "smallint.h"
 #include "objgenerator.h"
+#include "lexer.h"
 
 #if 0 // print debugging info
 #define DEBUG_PRINT (1)
@@ -74,8 +75,8 @@ void mp_init(void) {
     MICROPY_PORT_INIT_FUNC;
 #endif
 
-    // __debug__ enabled by default
+    // optimization disabled by default
-    mp_set_debug(true);
+    mp_optimise_value = 0;
 
     // init global module stuff
     mp_module_init();

py/runtime.h

@@ -54,8 +54,6 @@ typedef struct _mp_arg_t {
 void mp_init(void);
 void mp_deinit(void);
 
-void mp_set_debug(bool value); // sets the value of __debug__; see lexer.c
-
 void mp_arg_check_num(uint n_args, uint n_kw, uint n_args_min, uint n_args_max, bool takes_kw);
 void mp_arg_parse_all(uint n_pos, const mp_obj_t *pos, mp_map_t *kws, uint n_allowed, const mp_arg_t *allowed, mp_arg_val_t *out_vals);
 void mp_arg_parse_all_kw_array(uint n_pos, uint n_kw, const mp_obj_t *args, uint n_allowed, const mp_arg_t *allowed, mp_arg_val_t *out_vals);

unix/main.c

@@ -30,6 +30,7 @@
 #include <string.h>
 #include <stdlib.h>
 #include <stdarg.h>
+#include <ctype.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <errno.h>
@@ -188,6 +189,7 @@ int usage(char **argv) {
 "usage: %s [<opts>] [-X <implopt>] [-c <command>] [<filename>]\n"
 "Options:\n"
 "-v : verbose (trace various operations); can be multiple\n"
+"-O[N] : apply bytecode optimizations of level N\n"
 "\n"
 "Implementation specific options:\n", argv[0]
 );
@@ -346,9 +348,13 @@ int main(int argc, char **argv) {
                 a += 1;
             } else if (strcmp(argv[a], "-v") == 0) {
                 mp_verbose_flag++;
-            } else if (strcmp(argv[a], "-O") == 0) {
+            } else if (strncmp(argv[a], "-O", 2) == 0) {
-                // optimisation; sets __debug__ to False
+                if (isdigit(argv[a][2])) {
-                mp_set_debug(false);
+                    mp_optimise_value = argv[a][2] & 0xf;
+                } else {
+                    mp_optimise_value = 0;
+                    for (char *p = argv[a] + 1; *p && *p == 'O'; p++, mp_optimise_value++);
+                }
             } else {
                 return usage(argv);
             }