[PATCH] reverse dependency support

The 'select' keyword defines a lower limit for symbols and allows to
select other symbols when a symbol is selected, e.g.:

config JOLIET
	bool "Microsoft Joliet CDROM extensions"
	select NLS

This means when JOLIET is selected, NLS will be selected as well.

scripts/kconfig/expr.c

@@ -55,6 +55,13 @@ struct expr *expr_alloc_and(struct expr *e1, struct expr *e2)
 	return e2 ? expr_alloc_two(E_AND, e1, e2) : e1;
 }
 
+struct expr *expr_alloc_or(struct expr *e1, struct expr *e2)
+{
+	if (!e1)
+		return e2;
+	return e2 ? expr_alloc_two(E_OR, e1, e2) : e1;
+}
+
 struct expr *expr_copy(struct expr *org)
 {
 	struct expr *e;
@@ -158,9 +165,22 @@ static void __expr_eliminate_eq(enum expr_type type, struct expr **ep1, struct e
 
 void expr_eliminate_eq(struct expr **ep1, struct expr **ep2)
 {
-	if (!e1 || !e2 || e1->type != e2->type)
+	if (!e1 || !e2)
 		return;
-	__expr_eliminate_eq(e1->type, ep1, ep2);
+	switch (e1->type) {
+	case E_OR:
+	case E_AND:
+		__expr_eliminate_eq(e1->type, ep1, ep2);
+	default:
+		;
+	}
+	if (e1->type != e2->type) switch (e2->type) {
+	case E_OR:
+	case E_AND:
+		__expr_eliminate_eq(e2->type, ep1, ep2);
+	default:
+		;
+	}
 	e1 = expr_eliminate_yn(e1);
 	e2 = expr_eliminate_yn(e2);
 }
@@ -1017,11 +1037,11 @@ void expr_print(struct expr *e, void (*fn)(void *, const char *), void *data, in
 		expr_print(e->right.expr, fn, data, E_AND);
 		break;
 	case E_CHOICE:
+		fn(data, e->right.sym->name);
 		if (e->left.expr) {
-			expr_print(e->left.expr, fn, data, E_CHOICE);
 			fn(data, " ^ ");
+			expr_print(e->left.expr, fn, data, E_CHOICE);
 		}
-		fn(data, e->right.sym->name);
 		break;
 	default:
 	  {

scripts/kconfig/expr.h

@@ -73,6 +73,7 @@ struct symbol {
 	int flags;
 	struct property *prop;
 	struct expr *dep, *dep2;
+	struct expr_value rev_dep;
 };
 
 #define for_all_symbols(i, sym) for (i = 0; i < 257; i++) for (sym = symbol_hash[i]; sym; sym = sym->next) if (sym->type != S_OTHER)
@@ -97,7 +98,7 @@ struct symbol {
 #define SYMBOL_HASHMASK		0xff
 
 enum prop_type {
-	P_UNKNOWN, P_PROMPT, P_COMMENT, P_MENU, P_DEFAULT, P_CHOICE
+	P_UNKNOWN, P_PROMPT, P_COMMENT, P_MENU, P_DEFAULT, P_CHOICE, P_SELECT
 };
 
 struct property {
@@ -152,6 +153,7 @@ struct expr *expr_alloc_one(enum expr_type type, struct expr *ce);
 struct expr *expr_alloc_two(enum expr_type type, struct expr *e1, struct expr *e2);
 struct expr *expr_alloc_comp(enum expr_type type, struct symbol *s1, struct symbol *s2);
 struct expr *expr_alloc_and(struct expr *e1, struct expr *e2);
+struct expr *expr_alloc_or(struct expr *e1, struct expr *e2);
 struct expr *expr_copy(struct expr *org);
 void expr_free(struct expr *e);
 int expr_eq(struct expr *e1, struct expr *e2);

scripts/kconfig/menu.c

@@ -138,7 +138,7 @@ void menu_finalize(struct menu *parent)
 	struct menu *menu, *last_menu;
 	struct symbol *sym;
 	struct property *prop;
-	struct expr *parentdep, *basedep, *dep, *dep2;
+	struct expr *parentdep, *basedep, *dep, *dep2, **ep;
 
 	sym = parent->sym;
 	if (parent->list) {
@@ -177,6 +177,11 @@ void menu_finalize(struct menu *parent)
 				if (menu->sym && menu->sym->type != S_TRISTATE)
 					dep = expr_trans_bool(dep);
 				prop->visible.expr = dep;
+				if (prop->type == P_SELECT) {
+					struct symbol *es = prop_get_symbol(prop);
+					es->rev_dep.expr = expr_alloc_or(es->rev_dep.expr,
+							expr_alloc_and(expr_alloc_symbol(menu->sym), expr_copy(dep)));
+				}
 			}
 		}
 		for (menu = parent->list; menu; menu = menu->next)
@@ -216,12 +221,20 @@ void menu_finalize(struct menu *parent)
 	for (menu = parent->list; menu; menu = menu->next) {
 		if (sym && sym_is_choice(sym) && menu->sym) {
 			menu->sym->flags |= SYMBOL_CHOICEVAL;
+			for (prop = menu->sym->prop; prop; prop = prop->next) {
+				if (prop->type != P_DEFAULT)
+					continue;
+				fprintf(stderr, "%s:%d:warning: defaults for choice values not supported\n",
+					prop->file->name, prop->lineno);
+			}
 			current_entry = menu;
 			menu_set_type(sym->type);
 			menu_add_symbol(P_CHOICE, sym, NULL);
 			prop = sym_get_choice_prop(sym);
-			prop->expr = expr_alloc_one(E_CHOICE, prop->expr);
-			prop->expr->right.sym = menu->sym;
+			for (ep = &prop->expr; *ep; ep = &(*ep)->left.expr)
+				;
+			*ep = expr_alloc_one(E_CHOICE, NULL);
+			(*ep)->right.sym = menu->sym;
 		}
 		if (menu->list && (!menu->prompt || !menu->prompt->text)) {
 			for (last_menu = menu->list; ; last_menu = last_menu->next) {
@@ -234,20 +247,46 @@ void menu_finalize(struct menu *parent)
 			menu->list = NULL;
 		}
 	}
+
+	if (sym && !sym_is_optional(sym) && parent->prompt) {
+		sym->rev_dep.expr = expr_alloc_or(sym->rev_dep.expr,
+				expr_alloc_and(parent->prompt->visible.expr,
+					expr_alloc_symbol(&symbol_mod)));
+	}
 }
 
 bool menu_is_visible(struct menu *menu)
 {
+	struct menu *child;
+	struct symbol *sym;
 	tristate visible;
 
 	if (!menu->prompt)
 		return false;
-	if (menu->sym) {
-		sym_calc_value(menu->sym);
+	sym = menu->sym;
+	if (sym) {
+		sym_calc_value(sym);
 		visible = menu->prompt->visible.tri;
 	} else
 		visible = menu->prompt->visible.tri = expr_calc_value(menu->prompt->visible.expr);
-	return visible != no;
+
+	if (sym && sym_is_choice(sym)) {
+		for (child = menu->list; child; child = child->next)
+			if (menu_is_visible(child))
+				break;
+		if (!child)
+			return false;
+	}
+
+	if (visible != no)
+		return true;
+	if (!sym || sym_get_tristate_value(menu->sym) == no)
+		return false;
+
+	for (child = menu->list; child; child = child->next)
+		if (menu_is_visible(child))
+			return true;
+	return false;
 }
 
 const char *menu_get_prompt(struct menu *menu)

scripts/kconfig/symbol.c

@@ -133,17 +133,25 @@ struct property *sym_get_default_prop(struct symbol *sym)
 static void sym_calc_visibility(struct symbol *sym)
 {
 	struct property *prop;
-	tristate visible, oldvisible;
+	tristate tri;
 
 	/* any prompt visible? */
-	oldvisible = sym->visible;
-	visible = no;
+	tri = no;
 	for_all_prompts(sym, prop) {
 		prop->visible.tri = expr_calc_value(prop->visible.expr);
-		visible = E_OR(visible, prop->visible.tri);
+		tri = E_OR(tri, prop->visible.tri);
 	}
-	if (oldvisible != visible) {
-		sym->visible = visible;
+	if (sym->visible != tri) {
+		sym->visible = tri;
+		sym_set_changed(sym);
+	}
+	if (sym_is_choice_value(sym))
+		return;
+	tri = no;
+	if (sym->rev_dep.expr)
+		tri = expr_calc_value(sym->rev_dep.expr);
+	if (sym->rev_dep.tri != tri) {
+		sym->rev_dep.tri = tri;
 		sym_set_changed(sym);
 	}
 }
@@ -195,6 +203,7 @@ void sym_calc_value(struct symbol *sym)
 
 	if (sym->flags & SYMBOL_VALID)
 		return;
+	sym->flags |= SYMBOL_VALID;
 
 	oldval = sym->curr;
 
@@ -209,11 +218,10 @@ void sym_calc_value(struct symbol *sym)
 		newval = symbol_no.curr;
 		break;
 	default:
-		newval.val = sym->name;
-		newval.tri = no;
-		goto out;
+		sym->curr.val = sym->name;
+		sym->curr.tri = no;
+		return;
 	}
-	sym->flags |= SYMBOL_VALID;
 	if (!sym_is_choice_value(sym))
 		sym->flags &= ~SYMBOL_WRITE;
 
@@ -228,7 +236,7 @@ void sym_calc_value(struct symbol *sym)
 		if (sym_is_choice_value(sym) && sym->visible == yes) {
 			prop = sym_get_choice_prop(sym);
 			newval.tri = (prop_get_symbol(prop)->curr.val == sym) ? yes : no;
-		} else if (sym->visible != no) {
+		} else if (E_OR(sym->visible, sym->rev_dep.tri) != no) {
 			sym->flags |= SYMBOL_WRITE;
 			if (sym_has_value(sym))
 				newval.tri = sym->user.tri;
@@ -237,11 +245,7 @@ void sym_calc_value(struct symbol *sym)
 				if (prop)
 					newval.tri = expr_calc_value(prop->expr);
 			}
-			newval.tri = E_AND(newval.tri, sym->visible);
-			/* if the symbol is visible and not optionial,
-			 * possibly ignore old user choice. */
-			if (!sym_is_optional(sym) && newval.tri == no)
-				newval.tri = sym->visible;
+			newval.tri = E_OR(E_AND(newval.tri, sym->visible), sym->rev_dep.tri);
 		} else if (!sym_is_choice(sym)) {
 			prop = sym_get_default_prop(sym);
 			if (prop) {
@@ -249,6 +253,12 @@ void sym_calc_value(struct symbol *sym)
 				newval.tri = expr_calc_value(prop->expr);
 			}
 		}
+		if (sym_get_type(sym) == S_BOOLEAN) {
+			if (newval.tri == mod)
+				newval.tri = yes;
+			if (sym->rev_dep.tri == mod)
+				sym->rev_dep.tri = yes;
+		}
 		break;
 	case S_STRING:
 	case S_HEX:
@@ -274,23 +284,6 @@ void sym_calc_value(struct symbol *sym)
 		;
 	}
 
-	switch (sym_get_type(sym)) {
-	case S_TRISTATE:
-		if (newval.tri != mod)
-			break;
-		sym_calc_value(modules_sym);
-		if (modules_sym->curr.tri == no)
-			newval.tri = yes;
-		break;
-	case S_BOOLEAN:
-		if (newval.tri == mod)
-			newval.tri = yes;
-		break;
-	default:
-		break;
-	}
-
-out:
 	sym->curr = newval;
 	if (sym_is_choice(sym) && newval.tri == yes)
 		sym->curr.val = sym_calc_choice(sym);
@@ -349,19 +342,13 @@ bool sym_tristate_within_range(struct symbol *sym, tristate val)
 	if (type != S_BOOLEAN && type != S_TRISTATE)
 		return false;
 
-	switch (val) {
-	case no:
-		if (sym_is_choice_value(sym) && sym->visible == yes)
-			return false;
-		return sym_is_optional(sym);
-	case mod:
-		if (sym_is_choice_value(sym) && sym->visible == yes)
-			return false;
-		return type == S_TRISTATE;
-	case yes:
-		return type == S_BOOLEAN || sym->visible == yes;
-	}
-	return false;
+	if (type == S_BOOLEAN && val == mod)
+		return false;
+	if (sym->visible <= sym->rev_dep.tri)
+		return false;
+	if (sym_is_choice_value(sym) && sym->visible == yes)
+		return val == yes;
+	return val >= sym->rev_dep.tri && val <= sym->visible;
 }
 
 bool sym_set_tristate_value(struct symbol *sym, tristate val)
@@ -534,15 +521,7 @@ const char *sym_get_string_value(struct symbol *sym)
 
 bool sym_is_changable(struct symbol *sym)
 {
-	if (sym->visible == no)
-		return false;
-	/* at least 'n' and 'y'/'m' is selectable */
-	if (sym_is_optional(sym))
-		return true;
-	/* no 'n', so 'y' and 'm' must be selectable */
-	if (sym_get_type(sym) == S_TRISTATE && sym->visible == yes)
-		return true;
-	return false;
+	return sym->visible > sym->rev_dep.tri;
 }
 
 struct symbol *sym_lookup(const char *name, int isconst)
@@ -663,7 +642,10 @@ const char *prop_get_type_name(enum prop_type type)
 		return "default";
 	case P_CHOICE:
 		return "choice";
-	default:
-		return "unknown";
+	case P_SELECT:
+		return "select";
+	case P_UNKNOWN:
+		break;
 	}
+	return "unknown";
 }

scripts/kconfig/zconf.tab.c_shipped

@@ -1406,6 +1406,7 @@ yyreduce:
   case 36:
 
     {
+	menu_add_symbol(P_SELECT, sym_lookup(yyvsp[-2].string, 0), yyvsp[-1].expr);
 	printd(DEBUG_PARSE, "%s:%d:select\n", zconf_curname(), zconf_lineno());
 ;}
     break;

scripts/kconfig/zconf.y

@@ -215,6 +215,7 @@ config_option: T_DEFAULT expr if_expr T_EOL
 
 config_option: T_SELECT T_WORD if_expr T_EOL
 {
+	menu_add_symbol(P_SELECT, sym_lookup($2, 0), $3);
 	printd(DEBUG_PARSE, "%s:%d:select\n", zconf_curname(), zconf_lineno());
 };