From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicolai Stange Subject: [PATCH RFC 13/13] symbol: do not inherit storage modifiers from base types at examination Date: Thu, 23 Jul 2015 01:24:41 +0200 Message-ID: <87bnf3ixmu.fsf@gmail.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from mail-wi0-f174.google.com ([209.85.212.174]:33751 "EHLO mail-wi0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752491AbbGVXYo (ORCPT ); Wed, 22 Jul 2015 19:24:44 -0400 Received: by wicmv11 with SMTP id mv11so715227wic.0 for ; Wed, 22 Jul 2015 16:24:43 -0700 (PDT) Received: from localhost.localdomain (x55b1cac6.dyn.telefonica.de. [85.177.202.198]) by smtp.gmail.com with ESMTPSA id lj2sm55312wic.1.2015.07.22.16.24.42 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 22 Jul 2015 16:24:42 -0700 (PDT) Sender: linux-sparse-owner@vger.kernel.org List-Id: linux-sparse@vger.kernel.org To: linux-sparse@vger.kernel.org Consider the following code snippet: static inline foo(int dummy, ...) {} static int a = 0; static void bar(void) { foo(0, a); } Sparse moans: test.c:5:9: warning: initializer for static storage duration object is not a constant expression The cause can be tracked down as follows: The anonymous node created by inline_function() for the variadic argument will get assigned to its base_type whatever the passed expression's ctype is. For the special case of a primary expression referencing a symbol, this ctype is the referenced symbol itself. Furthermore, inline_function() sets that symbol node's initializer to this expression. Now, when the anonymous symbol node is evaluated, its base_type is handled in examine_base_type(). This applies the base_type's modifiers, i.e. the referenced symbol's MOD_STATIC in this case, to the inheriting ctype, that of the anonymous node, itself. This in turn instructs the evaluation of the symbol's initializer to allow constant expressions only. Do not inherit a base_type's storage related modifiers in examine_base_type(). Signed-off-by: Nicolai Stange --- symbol.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/symbol.c b/symbol.c index cbc846b..605ec1c 100644 --- a/symbol.c +++ b/symbol.c @@ -214,7 +214,8 @@ static struct symbol *examine_base_type(struct symbol *sym) if (!base_type || base_type->type == SYM_PTR) return base_type; sym->ctype.as |= base_type->ctype.as; - sym->ctype.modifiers |= base_type->ctype.modifiers & MOD_PTRINHERIT; + sym->ctype.modifiers |= base_type->ctype.modifiers & MOD_PTRINHERIT & + ~MOD_STORAGE; concat_ptr_list((struct ptr_list *)base_type->ctype.contexts, (struct ptr_list **)&sym->ctype.contexts); if (base_type->type == SYM_NODE) { -- 2.4.5