kconfig: do not clear SYMBOL_VALID when reading include/config/auto.conf

When conf_read_simple() is called with S_DEF_AUTO, it is meant to read
previous symbol values from include/config/auto.conf to determine which
include/config/* files should be touched.

This process should not modify the current symbol status in any way.
However, conf_touch_deps() currently invalidates all symbol values and
recalculates them, which is totally unneeded.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Author: masahir0y

scripts/kconfig/confdata.c

@@ -385,7 +385,7 @@ int conf_read_simple(const char *name, int def)
 
 	def_flags = SYMBOL_DEF << def;
 	for_all_symbols(sym) {
-		sym->flags &= ~(def_flags|SYMBOL_VALID);
+		sym->flags &= ~def_flags;
 		switch (sym->type) {
 		case S_INT:
 		case S_HEX:
@@ -398,7 +398,11 @@ int conf_read_simple(const char *name, int def)
 		}
 	}
 
-	expr_invalidate_all();
+	if (def == S_DEF_USER) {
+		for_all_symbols(sym)
+			sym->flags &= ~SYMBOL_VALID;
+		expr_invalidate_all();
+	}
 
 	while (getline_stripped(&line, &line_asize, in) != -1) {
 		struct menu *choice;
@@ -464,6 +468,9 @@ int conf_read_simple(const char *name, int def)
 		if (conf_set_sym_val(sym, def, def_flags, val))
 			continue;
 
+		if (def != S_DEF_USER)
+			continue;
+
 		/*
 		 * If this is a choice member, give it the highest priority.
 		 * If conflicting CONFIG options are given from an input file,
@@ -967,10 +974,8 @@ static int conf_touch_deps(void)
 	depfile_path[depfile_prefix_len] = 0;
 
 	conf_read_simple(name, S_DEF_AUTO);
-	sym_calc_value(modules_sym);
 
 	for_all_symbols(sym) {
-		sym_calc_value(sym);
 		if (sym_is_choice(sym))
 			continue;
 		if (sym->flags & SYMBOL_WRITE) {
@@ -1084,12 +1089,12 @@ int conf_write_autoconf(int overwrite)
 	if (ret)
 		return -1;
 
-	if (conf_touch_deps())
-		return 1;
-
 	for_all_symbols(sym)
 		sym_calc_value(sym);
 
+	if (conf_touch_deps())
+		return 1;
+
 	ret = __conf_write_autoconf(conf_get_autoheader_name(),
 				    print_symbol_for_c,
 				    &comment_style_c);