py/objdict: Make .fromkeys() method configurable.

On by default, turned off for minimal/bare-arm. Saves 144 bytes on x86.

ports/bare-arm/mpconfigport.h

@@ -22,6 +22,7 @@
 #define MICROPY_BUILTIN_METHOD_CHECK_SELF_ARG (0)
 #define MICROPY_PY_ASYNC_AWAIT (0)
 #define MICROPY_PY_BUILTINS_BYTEARRAY (0)
+#define MICROPY_PY_BUILTINS_DICT_FROMKEYS (0)
 #define MICROPY_PY_BUILTINS_MEMORYVIEW (0)
 #define MICROPY_PY_BUILTINS_ENUMERATE (0)
 #define MICROPY_PY_BUILTINS_FROZENSET (0)

ports/minimal/mpconfigport.h

@@ -31,6 +31,7 @@
 #define MICROPY_BUILTIN_METHOD_CHECK_SELF_ARG (0)
 #define MICROPY_PY_ASYNC_AWAIT      (0)
 #define MICROPY_PY_BUILTINS_BYTEARRAY (0)
+#define MICROPY_PY_BUILTINS_DICT_FROMKEYS (0)
 #define MICROPY_PY_BUILTINS_MEMORYVIEW (0)
 #define MICROPY_PY_BUILTINS_ENUMERATE (0)
 #define MICROPY_PY_BUILTINS_FILTER  (0)

py/mpconfig.h

@@ -804,6 +804,11 @@ typedef double mp_float_t;
 #define MICROPY_PY_BUILTINS_BYTEARRAY (1)
 #endif
 
+// Whether to support dict.fromkeys() class method
+#ifndef MICROPY_PY_BUILTINS_DICT_FROMKEYS
+#define MICROPY_PY_BUILTINS_DICT_FROMKEYS (1)
+#endif
+
 // Whether to support memoryview object
 #ifndef MICROPY_PY_BUILTINS_MEMORYVIEW
 #define MICROPY_PY_BUILTINS_MEMORYVIEW (0)

py/objdict.c

@@ -227,6 +227,7 @@ STATIC mp_obj_t dict_copy(mp_obj_t self_in) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(dict_copy_obj, dict_copy);
 
+#if MICROPY_PY_BUILTINS_DICT_FROMKEYS
 // this is a classmethod
 STATIC mp_obj_t dict_fromkeys(size_t n_args, const mp_obj_t *args) {
     mp_obj_t iter = mp_getiter(args[1], NULL);
@@ -256,6 +257,7 @@ STATIC mp_obj_t dict_fromkeys(size_t n_args, const mp_obj_t *args) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(dict_fromkeys_fun_obj, 2, 3, dict_fromkeys);
 STATIC MP_DEFINE_CONST_CLASSMETHOD_OBJ(dict_fromkeys_obj, MP_ROM_PTR(&dict_fromkeys_fun_obj));
+#endif
 
 STATIC mp_obj_t dict_get_helper(size_t n_args, const mp_obj_t *args, mp_map_lookup_kind_t lookup_kind) {
     mp_check_self(MP_OBJ_IS_DICT_TYPE(args[0]));
@@ -528,7 +530,9 @@ STATIC mp_obj_t dict_getiter(mp_obj_t self_in, mp_obj_iter_buf_t *iter_buf) {
 STATIC const mp_rom_map_elem_t dict_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_clear), MP_ROM_PTR(&dict_clear_obj) },
     { MP_ROM_QSTR(MP_QSTR_copy), MP_ROM_PTR(&dict_copy_obj) },
+    #if MICROPY_PY_BUILTINS_DICT_FROMKEYS
     { MP_ROM_QSTR(MP_QSTR_fromkeys), MP_ROM_PTR(&dict_fromkeys_obj) },
+    #endif
     { MP_ROM_QSTR(MP_QSTR_get), MP_ROM_PTR(&dict_get_obj) },
     { MP_ROM_QSTR(MP_QSTR_items), MP_ROM_PTR(&dict_items_obj) },
     { MP_ROM_QSTR(MP_QSTR_keys), MP_ROM_PTR(&dict_keys_obj) },