+/*
+ * When we check for recursive dependencies we use a stack to save
+ * current state so we can print out relevant info to user.
+ * The entries are located on the call stack so no need to free memory.
+ * Note insert() remove() must always match to properly clear the stack.
+ */
+static struct dep_stack {
+ struct dep_stack *prev, *next;
+ struct symbol *sym;
+ struct property *prop;
+ struct expr *expr;
+} *check_top;
+
+static void dep_stack_insert(struct dep_stack *stack, struct symbol *sym)
+{
+ memset(stack, 0, sizeof(*stack));
+ if (check_top)
+ check_top->next = stack;
+ stack->prev = check_top;
+ stack->sym = sym;
+ check_top = stack;
+}
+
+static void dep_stack_remove(void)
+{
+ check_top = check_top->prev;
+ if (check_top)
+ check_top->next = NULL;
+}
+
+/*
+ * Called when we have detected a recursive dependency.
+ * check_top point to the top of the stact so we use
+ * the ->prev pointer to locate the bottom of the stack.
+ */
+static void sym_check_print_recursive(struct symbol *last_sym)
+{
+ struct dep_stack *stack;
+ struct symbol *sym, *next_sym;
+ struct menu *menu = NULL;
+ struct property *prop;
+ struct dep_stack cv_stack;
+
+ if (sym_is_choice_value(last_sym)) {
+ dep_stack_insert(&cv_stack, last_sym);
+ last_sym = prop_get_symbol(sym_get_choice_prop(last_sym));
+ }
+
+ for (stack = check_top; stack != NULL; stack = stack->prev)
+ if (stack->sym == last_sym)
+ break;
+ if (!stack) {
+ fprintf(stderr, "unexpected recursive dependency error\n");
+ return;
+ }
+
+ for (; stack; stack = stack->next) {
+ sym = stack->sym;
+ next_sym = stack->next ? stack->next->sym : last_sym;
+ prop = stack->prop;
+ if (prop == NULL)
+ prop = stack->sym->prop;
+
+ /* for choice values find the menu entry (used below) */
+ if (sym_is_choice(sym) || sym_is_choice_value(sym)) {
+ for (prop = sym->prop; prop; prop = prop->next) {
+ menu = prop->menu;
+ if (prop->menu)
+ break;
+ }
+ }
+ if (stack->sym == last_sym)
+ fprintf(stderr, "%s:%d:error: recursive dependency detected!\n",
+ prop->file->name, prop->lineno);
+
+ if (stack->expr) {
+ fprintf(stderr, "%s:%d:\tsymbol %s %s value contains %s\n",
+ prop->file->name, prop->lineno,
+ sym->name ? sym->name : "<choice>",
+ prop_get_type_name(prop->type),
+ next_sym->name ? next_sym->name : "<choice>");
+ } else if (stack->prop) {
+ fprintf(stderr, "%s:%d:\tsymbol %s depends on %s\n",
+ prop->file->name, prop->lineno,
+ sym->name ? sym->name : "<choice>",
+ next_sym->name ? next_sym->name : "<choice>");
+ } else if (sym_is_choice(sym)) {
+ fprintf(stderr, "%s:%d:\tchoice %s contains symbol %s\n",
+ menu->file->name, menu->lineno,
+ sym->name ? sym->name : "<choice>",
+ next_sym->name ? next_sym->name : "<choice>");
+ } else if (sym_is_choice_value(sym)) {
+ fprintf(stderr, "%s:%d:\tsymbol %s is part of choice %s\n",
+ menu->file->name, menu->lineno,
+ sym->name ? sym->name : "<choice>",
+ next_sym->name ? next_sym->name : "<choice>");
+ } else {
+ fprintf(stderr, "%s:%d:\tsymbol %s is selected by %s\n",
+ prop->file->name, prop->lineno,
+ sym->name ? sym->name : "<choice>",
+ next_sym->name ? next_sym->name : "<choice>");
+ }
+ }
+
+ fprintf(stderr,
+ "For a resolution refer to Documentation/kbuild/kconfig-language.txt\n"
+ "subsection \"Kconfig recursive dependency limitations\"\n"
+ "\n");
+
+ if (check_top == &cv_stack)
+ dep_stack_remove();
+}