tools/mpy-tool.py: Skip generating frozen mp_raw_code_t when possible.

This reduces frozen code size by using the bytecode directly as the
`mp_proto_fun_t`.

Signed-off-by: Damien George <damien@micropython.org>

py/emitglue.c

@@ -183,6 +183,18 @@ mp_obj_t mp_make_function_from_proto_fun(mp_proto_fun_t proto_fun, const mp_modu
     // def_kw_args must be MP_OBJ_NULL or a dict
     assert(def_args == NULL || def_args[1] == MP_OBJ_NULL || mp_obj_is_type(def_args[1], &mp_type_dict));
 
+    #if MICROPY_MODULE_FROZEN_MPY
+    if (mp_proto_fun_is_bytecode(proto_fun)) {
+        const uint8_t *bc = proto_fun;
+        mp_obj_t fun = mp_obj_new_fun_bc(def_args, bc, context, NULL);
+        MP_BC_PRELUDE_SIG_DECODE(bc);
+        if (scope_flags & MP_SCOPE_FLAG_GENERATOR) {
+            ((mp_obj_base_t *)MP_OBJ_TO_PTR(fun))->type = &mp_type_gen_wrap;
+        }
+        return fun;
+    }
+    #endif
+
     // the proto-function is a mp_raw_code_t
     const mp_raw_code_t *rc = proto_fun;
 

tools/mpy-tool.py

@@ -911,6 +911,13 @@ class RawCode(object):
             raw_code_type = "mp_raw_code_t"
         else:
             raw_code_type = "mp_raw_code_truncated_t"
+
+        empty_children = len(self.children) == 0 and prelude_ptr is None
+        generate_minimal = self.code_kind == MP_CODE_BYTECODE and empty_children
+
+        if generate_minimal:
+            print("#if MICROPY_PERSISTENT_CODE_SAVE")
+
         print("static const %s proto_fun_%s = {" % (raw_code_type, self.escaped_name))
         print("    .proto_fun_indicator[0] = MP_PROTO_FUN_INDICATOR_RAW_CODE_0,")
         print("    .proto_fun_indicator[1] = MP_PROTO_FUN_INDICATOR_RAW_CODE_1,")
@@ -961,6 +968,11 @@ class RawCode(object):
             print("    .asm_type_sig = %u," % type_sig)
         print("};")
 
+        if generate_minimal:
+            print("#else")
+            print("#define proto_fun_%s fun_data_%s[0]" % (self.escaped_name, self.escaped_name))
+            print("#endif")
+
         global raw_code_count, raw_code_content
         raw_code_count += 1
         raw_code_content += 4 * 4