From patchwork Fri Feb 6 05:36:55 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Al Viro X-Patchwork-Id: 5806 Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n165axkT017161 for ; Fri, 6 Feb 2009 05:36:59 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750894AbZBFFg6 (ORCPT ); Fri, 6 Feb 2009 00:36:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751349AbZBFFg6 (ORCPT ); Fri, 6 Feb 2009 00:36:58 -0500 Received: from zeniv.linux.org.uk ([195.92.253.2]:58668 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750894AbZBFFg5 (ORCPT ); Fri, 6 Feb 2009 00:36:57 -0500 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.69 #1 (Red Hat Linux)) id 1LVJOZ-0007Tu-BZ; Fri, 06 Feb 2009 05:36:55 +0000 Date: Fri, 6 Feb 2009 05:36:55 +0000 From: Al Viro To: Derek M Jones Cc: Christopher Li , linux-sparse@vger.kernel.org Subject: Re: fun with declarations and definitions Message-ID: <20090206053655.GS28946@ZenIV.linux.org.uk> References: <20090202073018.GB28946@ZenIV.linux.org.uk> <70318cbf0902021907w634ffc6dm693022b23a0eabfc@mail.gmail.com> <20090203041317.GH28946@ZenIV.linux.org.uk> <70318cbf0902051040m7506a365s784a591667358f1f@mail.gmail.com> <498B3435.8010506@knosof.co.uk> <20090205202811.GO28946@ZenIV.linux.org.uk> <20090205211921.GP28946@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20090205211921.GP28946@ZenIV.linux.org.uk> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-sparse-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sparse@vger.kernel.org On Thu, Feb 05, 2009 at 09:19:21PM +0000, Al Viro wrote: > IOW, direct_declarator() (which doubles for direct-abstract-declarator) should > have more than one-bit indication of which case we've got. Right now it's > done by "have we passed a non-NULL ident ** to store the identifier being > declared"; that's not enough. What we need is explicit 'is that a part of > parameter declaration' flag; then the rule turns into > if (p && *p) > fn = 1; /* we'd seen identifier already, can't be nested */ > else if match_op(next, ')') > fn = 1; /* empty list can't be direct-declarator or > * direct-abstract-declarator */ > else > fn = (in_parameter && lookup_type(next)); Umm... It's a bit more subtle (p goes NULL after the nested one is handled), so we need to keep track of "don't allow nested declarator from that point on" explicitly. Patch follows: Subject: [PATCH] Handle nested declarators vs. parameter lists correctly Seeing a typedef name after ( means that we have a parameter-type-list only if we are parsing a parameter declaration or a typename; otherwise it might very well be a redeclaration (e.g. int (T); when T had been a typedef in outer scope). Signed-off-by: Al Viro --- parse.c | 26 +++++++++++++++----------- validation/nested-declarator.c | 11 +++++++++++ 2 files changed, 26 insertions(+), 11 deletions(-) create mode 100644 validation/nested-declarator.c diff --git a/parse.c b/parse.c index 7e3191a..73e7b65 100644 --- a/parse.c +++ b/parse.c @@ -1227,7 +1227,7 @@ static struct token *abstract_array_declarator(struct token *token, struct symbo } static struct token *parameter_type_list(struct token *, struct symbol *, struct ident **p); -static struct token *declarator(struct token *token, struct symbol *sym, struct ident **p); +static struct token *declarator(struct token *token, struct symbol *sym, struct ident **p, int); static struct token *handle_attributes(struct token *token, struct ctype *ctype, unsigned int keywords) { @@ -1247,13 +1247,15 @@ static struct token *handle_attributes(struct token *token, struct ctype *ctype, return token; } -static struct token *direct_declarator(struct token *token, struct symbol *decl, struct ident **p) +static struct token *direct_declarator(struct token *token, struct symbol *decl, struct ident **p, int prefer_abstract) { struct ctype *ctype = &decl->ctype; + int dont_nest = 0; if (p && token_type(token) == TOKEN_IDENT) { *p = token->ident; token = token->next; + dont_nest = 1; } for (;;) { @@ -1275,14 +1277,16 @@ static struct token *direct_declarator(struct token *token, struct symbol *decl, int fn; next = handle_attributes(next, ctype, KW_ATTRIBUTE); - fn = (p && *p) || match_op(next, ')') || lookup_type(next); + fn = dont_nest || match_op(next, ')') || + (prefer_abstract && lookup_type(next)); if (!fn) { struct symbol *base_type = ctype->base_type; - token = declarator(next, decl, p); + token = declarator(next, decl, p, prefer_abstract); token = expect(token, ')', "in nested declarator"); while (ctype->base_type != base_type) ctype = &ctype->base_type->ctype; + dont_nest = 1; p = NULL; continue; } @@ -1336,10 +1340,10 @@ static struct token *pointer(struct token *token, struct ctype *ctype) return token; } -static struct token *declarator(struct token *token, struct symbol *sym, struct ident **p) +static struct token *declarator(struct token *token, struct symbol *sym, struct ident **p, int prefer_abstract) { token = pointer(token, &sym->ctype); - return direct_declarator(token, sym, p); + return direct_declarator(token, sym, p, prefer_abstract); } static struct token *handle_bitfield(struct token *token, struct symbol *decl) @@ -1399,7 +1403,7 @@ static struct token *declaration_list(struct token *token, struct symbol_list ** struct ident *ident = NULL; struct symbol *decl = alloc_symbol(token->pos, SYM_NODE); decl->ctype = ctype; - token = declarator(token, decl, &ident); + token = declarator(token, decl, &ident, 0); decl->ident = ident; if (match_op(token, ':')) { token = handle_bitfield(token, decl); @@ -1439,7 +1443,7 @@ static struct token *parameter_declaration(struct token *token, struct symbol ** sym = alloc_symbol(token->pos, SYM_NODE); sym->ctype = ctype; *tree = sym; - token = declarator(token, sym, &ident); + token = declarator(token, sym, &ident, 1); sym->ident = ident; apply_modifiers(token->pos, &sym->ctype); sym->endpos = token->pos; @@ -1451,7 +1455,7 @@ struct token *typename(struct token *token, struct symbol **p, int mod) struct symbol *sym = alloc_symbol(token->pos, SYM_NODE); *p = sym; token = declaration_specifiers(token, &sym->ctype, 0); - token = declarator(token, sym, NULL); + token = declarator(token, sym, NULL, 1); apply_modifiers(token->pos, &sym->ctype); if (sym->ctype.modifiers & MOD_STORAGE & ~mod) warning(sym->pos, "storage class in typename (%s)", @@ -2261,7 +2265,7 @@ struct token *external_declaration(struct token *token, struct symbol_list **lis token = declaration_specifiers(token, &ctype, 0); decl = alloc_symbol(token->pos, SYM_NODE); decl->ctype = ctype; - token = declarator(token, decl, &ident); + token = declarator(token, decl, &ident, 0); apply_modifiers(token->pos, &decl->ctype); decl->endpos = token->pos; @@ -2333,7 +2337,7 @@ struct token *external_declaration(struct token *token, struct symbol_list **lis decl = alloc_symbol(token->pos, SYM_NODE); decl->ctype = ctype; token = declaration_specifiers(token, &decl->ctype, 1); - token = declarator(token, decl, &ident); + token = declarator(token, decl, &ident, 0); apply_modifiers(token->pos, &decl->ctype); decl->endpos = token->pos; if (!ident) { diff --git a/validation/nested-declarator.c b/validation/nested-declarator.c new file mode 100644 index 0000000..24ed833 --- /dev/null +++ b/validation/nested-declarator.c @@ -0,0 +1,11 @@ +typedef int T; +extern void f(int); +static void g(int x) +{ + int (T); + T = x; + f(T); +} +/* + * check-name: nested declarator vs. parameters + */