linux-kernel - [PATCH 4/5] kconfig: remove S_OTHER symbol type and correct dependency tracking

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Message-Id: <1543569352-4899-4-git-send-email-yamada.masahiro@socionext.com>
Date:   Fri, 30 Nov 2018 18:15:51 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     linux-kbuild@...r.kernel.org
Cc:     Sam Ravnborg <sam@...nborg.org>,
        Ulf Magnusson <ulfalizer@...il.com>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 4/5] kconfig: remove S_OTHER symbol type and correct dependency tracking

The S_OTHER type could be set only when conf_read_simple() is reading
include/config/auto.conf file.

For example, CONFIG_FOO=y exists in include/config/auto.conf but it is
missing from the currently parsed Kconfig files, sym_lookup() allocates
a new symbol, and sets its type to S_OTHER.

Strangely, it will be set to S_STRING by conf_set_sym_val() a few lines
below while it is obviously bool or tristate type. On the other hand,
when CONFIG_BAR="bar" is being dropped from include/config/auto.conf,
its type remains S_OTHER. Because for_all_symbols() omits S_OTHER
symbols, conf_touch_deps() misses to touch include/config/bar.h

This behavior has been a pretty mystery for me, and digging the git
histroy did not help. At least, touching depfiles is broken for string
type symbols.

I removed S_OTHER entirely, and reimplemented it more simply.

If CONFIG_FOO was visible in the previous syncconfig, but is missing
now, what we want to do is quite simple; just call conf_touch_dep()
to touch include/config/foo.h instead of allocating a new symbol data.

Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
---

 scripts/kconfig/confdata.c | 33 ++++++++++++++-------------------
 scripts/kconfig/expr.h     |  4 ++--
 scripts/kconfig/symbol.c   |  3 ---
 3 files changed, 16 insertions(+), 24 deletions(-)

diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index 7263b83..800fb16 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -227,14 +227,6 @@ static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p)
 			conf_warning("symbol value '%s' invalid for %s",
 				     p, sym->name);
 		return 1;
-	case S_OTHER:
-		if (*p != '"') {
-			for (p2 = p; *p2 && !isspace(*p2); p2++)
-				;
-			sym->type = S_STRING;
-			goto done;
-		}
-		/* fall through */
 	case S_STRING:
 		if (*p++ != '"')
 			break;
@@ -253,7 +245,6 @@ static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p)
 		/* fall through */
 	case S_INT:
 	case S_HEX:
-	done:
 		if (sym_string_valid(sym, p)) {
 			sym->def[def].val = xstrdup(p);
 			sym->flags |= def_flags;
@@ -434,17 +425,22 @@ int conf_read_simple(const char *name, int def)
 				if (*p2 == '\r')
 					*p2 = 0;
 			}
-			if (def == S_DEF_USER) {
-				sym = sym_find(line + strlen(CONFIG_));
-				if (!sym) {
+
+			sym = sym_find(line + strlen(CONFIG_));
+			if (!sym) {
+				if (def == S_DEF_AUTO)
+					/*
+					 * Reading from include/config/auto.conf
+					 * If CONFIG_FOO previously existed in
+					 * auto.conf but it is missing now,
+					 * include/config/foo.h must be touched.
+					 */
+					conf_touch_dep(line + strlen(CONFIG_));
+				else
 					sym_add_change_count(1);
-					continue;
-				}
-			} else {
-				sym = sym_lookup(line + strlen(CONFIG_), 0);
-				if (sym->type == S_UNKNOWN)
-					sym->type = S_OTHER;
+				continue;
 			}
+
 			if (sym->flags & def_flags) {
 				conf_warning("override: reassigning to symbol %s", sym->name);
 			}
@@ -710,7 +706,6 @@ static void conf_write_symbol(FILE *fp, struct symbol *sym,
 	const char *str;
 
 	switch (sym->type) {
-	case S_OTHER:
 	case S_UNKNOWN:
 		break;
 	case S_STRING:
diff --git a/scripts/kconfig/expr.h b/scripts/kconfig/expr.h
index 7c329e1..2b7e222 100644
--- a/scripts/kconfig/expr.h
+++ b/scripts/kconfig/expr.h
@@ -62,7 +62,7 @@ struct symbol_value {
 };
 
 enum symbol_type {
-	S_UNKNOWN, S_BOOLEAN, S_TRISTATE, S_INT, S_HEX, S_STRING, S_OTHER
+	S_UNKNOWN, S_BOOLEAN, S_TRISTATE, S_INT, S_HEX, S_STRING
 };
 
 /* enum values are used as index to symbol.def[] */
@@ -131,7 +131,7 @@ struct symbol {
 	struct expr_value implied;
 };
 
-#define for_all_symbols(i, sym) for (i = 0; i < SYMBOL_HASHSIZE; i++) for (sym = symbol_hash[i]; sym; sym = sym->next) if (sym->type != S_OTHER)
+#define for_all_symbols(i, sym) for (i = 0; i < SYMBOL_HASHSIZE; i++) for (sym = symbol_hash[i]; sym; sym = sym->next)
 
 #define SYMBOL_CONST      0x0001  /* symbol is const */
 #define SYMBOL_CHECK      0x0008  /* used during dependency checking */
diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c
index 703b9b8..2e6bf36 100644
--- a/scripts/kconfig/symbol.c
+++ b/scripts/kconfig/symbol.c
@@ -61,8 +61,6 @@ const char *sym_type_name(enum symbol_type type)
 		return "string";
 	case S_UNKNOWN:
 		return "unknown";
-	case S_OTHER:
-		break;
 	}
 	return "???";
 }
@@ -757,7 +755,6 @@ const char *sym_get_string_default(struct symbol *sym)
 		return str;
 	case S_STRING:
 		return str;
-	case S_OTHER:
 	case S_UNKNOWN:
 		break;
 	}
-- 
2.7.4