py: Improve efficiency of MP_OBJ_IS_STR_OR_BYTES.

Saves ROM (16 on stmhal, 240 on 64-bit unix) and should be quicker since
there is 1 less branch.

py/obj.h

@@ -74,7 +74,7 @@ typedef struct _mp_obj_base_t mp_obj_base_t;
 #define MP_OBJ_IS_TYPE(o, t) (MP_OBJ_IS_OBJ(o) && (((mp_obj_base_t*)(o))->type == (t))) // this does not work for checking int, str or fun; use below macros for that
 #define MP_OBJ_IS_INT(o) (MP_OBJ_IS_SMALL_INT(o) || MP_OBJ_IS_TYPE(o, &mp_type_int))
 #define MP_OBJ_IS_STR(o) (MP_OBJ_IS_QSTR(o) || MP_OBJ_IS_TYPE(o, &mp_type_str))
-#define MP_OBJ_IS_STR_OR_BYTES(o) (MP_OBJ_IS_STR(o) || MP_OBJ_IS_TYPE(o, &mp_type_bytes))
+#define MP_OBJ_IS_STR_OR_BYTES(o) (MP_OBJ_IS_QSTR(o) || (MP_OBJ_IS_OBJ(o) && ((mp_obj_base_t*)(o))->type->binary_op == mp_obj_str_binary_op))
 #define MP_OBJ_IS_FUN(o) (MP_OBJ_IS_OBJ(o) && (((mp_obj_base_t*)(o))->type->binary_op == mp_obj_fun_binary_op))
 
 #define MP_OBJ_SMALL_INT_VALUE(o) (((mp_int_t)(o)) >> 1)

py/objint.c

@@ -38,6 +38,7 @@
 #include "smallint.h"
 #include "mpz.h"
 #include "objint.h"
+#include "objstr.h"
 #include "runtime0.h"
 #include "runtime.h"
 

py/objstr.c

@@ -247,6 +247,9 @@ STATIC const byte *find_subbytes(const byte *haystack, mp_uint_t hlen, const byt
     return NULL;
 }
 
+// Note: this function is used to check if an object is a str or bytes, which
+// works because both those types use it as their binary_op method.  Revisit
+// MP_OBJ_IS_STR_OR_BYTES if this fact changes.
 mp_obj_t mp_obj_str_binary_op(int op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
     GET_STR_DATA_LEN(lhs_in, lhs_data, lhs_len);
     mp_obj_type_t *lhs_type = mp_obj_get_type(lhs_in);