extmod/modure: Make regex dump-code debugging feature optional.

Enabled via MICROPY_PY_URE_DEBUG, disabled by default (but enabled on unix
coverage build).  This is a rarely used feature that costs a lot of code
(500-800 bytes flash).  Debugging of regular expressions can be done
offline with other tools.

extmod/modure.c

@@ -382,6 +382,7 @@ STATIC const mp_obj_type_t re_type = {
 };
 
 STATIC mp_obj_t mod_re_compile(size_t n_args, const mp_obj_t *args) {
+    (void)n_args;
     const char *re_str = mp_obj_str_get_str(args[0]);
     int size = re1_5_sizecode(re_str);
     if (size == -1) {
@@ -389,18 +390,22 @@ STATIC mp_obj_t mod_re_compile(size_t n_args, const mp_obj_t *args) {
     }
     mp_obj_re_t *o = m_new_obj_var(mp_obj_re_t, char, size);
     o->base.type = &re_type;
+    #if MICROPY_PY_URE_DEBUG
     int flags = 0;
     if (n_args > 1) {
         flags = mp_obj_get_int(args[1]);
     }
+    #endif
     int error = re1_5_compilecode(&o->re, re_str);
     if (error != 0) {
 error:
         mp_raise_ValueError("Error in regex");
     }
+    #if MICROPY_PY_URE_DEBUG
     if (flags & FLAG_DEBUG) {
         re1_5_dumpcode(&o->re);
     }
+    #endif
     return MP_OBJ_FROM_PTR(o);
 }
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_re_compile_obj, 1, 2, mod_re_compile);
@@ -440,7 +445,9 @@ STATIC const mp_rom_map_elem_t mp_module_re_globals_table[] = {
     #if MICROPY_PY_URE_SUB
     { MP_ROM_QSTR(MP_QSTR_sub), MP_ROM_PTR(&mod_re_sub_obj) },
     #endif
+    #if MICROPY_PY_URE_DEBUG
     { MP_ROM_QSTR(MP_QSTR_DEBUG), MP_ROM_INT(FLAG_DEBUG) },
+    #endif
 };
 
 STATIC MP_DEFINE_CONST_DICT(mp_module_re_globals, mp_module_re_globals_table);
@@ -455,7 +462,9 @@ const mp_obj_module_t mp_module_ure = {
 
 #define re1_5_fatal(x) assert(!x)
 #include "re1.5/compilecode.c"
+#if MICROPY_PY_URE_DEBUG
 #include "re1.5/dumpcode.c"
+#endif
 #include "re1.5/recursiveloop.c"
 #include "re1.5/charclass.c"
 

ports/unix/mpconfigport_coverage.h

@@ -50,6 +50,7 @@
 #define MICROPY_PY_URANDOM_EXTRA_FUNCS (1)
 #define MICROPY_PY_IO_BUFFEREDWRITER (1)
 #define MICROPY_PY_IO_RESOURCE_STREAM (1)
+#define MICROPY_PY_URE_DEBUG           (1)
 #define MICROPY_PY_URE_MATCH_GROUPS    (1)
 #define MICROPY_PY_URE_MATCH_SPAN_START_END (1)
 #define MICROPY_PY_URE_SUB             (1)

py/mpconfig.h

@@ -1259,6 +1259,10 @@ typedef double mp_float_t;
 #define MICROPY_PY_URE (0)
 #endif
 
+#ifndef MICROPY_PY_URE_DEBUG
+#define MICROPY_PY_URE_DEBUG (0)
+#endif
+
 #ifndef MICROPY_PY_URE_MATCH_GROUPS
 #define MICROPY_PY_URE_MATCH_GROUPS (0)
 #endif

tests/extmod/ure_debug.py

 # test printing debugging info when compiling
 try:
     import ure
-except ImportError:
+    ure.DEBUG
+except (ImportError, AttributeError):
     print("SKIP")
     raise SystemExit