From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 7E2B53858407 for ; Fri, 17 Dec 2021 19:33:06 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 7E2B53858407 Received: from mail-qk1-f199.google.com (mail-qk1-f199.google.com [209.85.222.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-613-hUHs7-oEPd687iBNwMkmSA-1; Fri, 17 Dec 2021 14:33:05 -0500 X-MC-Unique: hUHs7-oEPd687iBNwMkmSA-1 Received: by mail-qk1-f199.google.com with SMTP id bk35-20020a05620a1a2300b0046d2a9b93dfso1530388qkb.16 for ; Fri, 17 Dec 2021 11:33:04 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=nZZX3xcUKcZ7fkv+SiKjHOlCItVh7NWTmtdMEBE3YKg=; b=5wd8g7vlgsYNOlYN9EZRK/WxAlXmC1N6Lfwe/PJNSIUi39OGsg9H8zuO+imZ10JQlV OiqvzcUhD1n7g3PW4HsdNSeaeo2leEVTT4mkiiPkUSiXAkORw//AWUH0YbWtk8BY2Ux5 DjiSnLKAYNFfljZ1zc/2KgFn+CzZx8hEzva5XjykeYwZ+imWtrS2ijooYFUGweDcl+6c Yfqde6iiEvwZa+ae20CqbzBeffF/3DD3uigFMn/bUdpHUxm90CBB1RxXhioexxykfjXB eI/kKEJjMr6DaZhogHj9VMM7Hg3zhLZTfyhgjfdzz4hlVXg/3XxUQG/HmMqQDbqpbeUq 4Jfg== X-Gm-Message-State: AOAM532Q1G44GTWTThsNjTGQM/3zIa5Z39DwB2zYwHK3raAJtEDDrGCZ KGc99VV6wetz7QDUOmQ0O7LOc59pu95M9Rh6Di7PJcZEnvthF0Gh7yaRlx6YIaDC6PvogoVKRxv SCuYr7kGlMCZ5EomIFw== X-Received: by 2002:a05:620a:2486:: with SMTP id i6mr2873227qkn.331.1639769583289; Fri, 17 Dec 2021 11:33:03 -0800 (PST) X-Google-Smtp-Source: ABdhPJwhPDp+W+EqRUUoPQtOZFbHgliFGU7t71QcYByBmOCwcJ8Vx06RHp/jeVCDGAXxgdF59l3Tig== X-Received: by 2002:a05:620a:2486:: with SMTP id i6mr2873204qkn.331.1639769582896; Fri, 17 Dec 2021 11:33:02 -0800 (PST) Received: from [192.168.1.149] (130-44-159-43.s15913.c3-0.arl-cbr1.sbo-arl.ma.cable.rcncustomer.com. [130.44.159.43]) by smtp.gmail.com with ESMTPSA id m20sm8156321qtx.39.2021.12.17.11.33.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 17 Dec 2021 11:33:02 -0800 (PST) Message-ID: <6f8ef9bc-47c2-ccb5-6238-a039114d7047@redhat.com> Date: Fri, 17 Dec 2021 14:33:01 -0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.0 Subject: Re: [PATCH v3] attribs: Fix wrong error with -Wno-attribute=A::b [PR103649] To: Marek Polacek Cc: Jakub Jelinek , GCC Patches , Joseph Myers References: <20211216223555.820800-1-polacek@redhat.com> <20211216225346.GA2646553@tucnak> <7d088a03-cddc-9287-aae1-e32532a21f12@redhat.com> From: Jason Merrill In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-14.1 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, NICE_REPLY_A, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 17 Dec 2021 19:33:08 -0000 On 12/17/21 13:14, Marek Polacek wrote: > On Thu, Dec 16, 2021 at 08:06:43PM -0500, Jason Merrill wrote: >> On 12/16/21 19:52, Marek Polacek wrote: >>> --- /dev/null >>> +++ b/gcc/testsuite/c-c++-common/Wno-attributes-6.c >>> @@ -0,0 +1,14 @@ >>> +/* PR c/103649 */ >>> +/* { dg-do compile { target { c || c++11 } } } */ >>> +/* { dg-additional-options "-Wno-attributes=foo::bar" } */ >>> +/* { dg-additional-options "-Wno-attributes=baz::" } */ >>> +/* { dg-additional-options "-Wno-attributes=womp::womp" } */ >>> +/* { dg-additional-options "-Wno-attributes=qux::foo" } */ >>> + >>> +[[foo::bar(1, 2)]]; /* { dg-warning "attribute ignored" } */ >>> +[[baz::bar(1, 2)]]; /* { dg-warning "attribute ignored" } */ >>> +[[foo::bar(1, 2)]] void f1(); >>> +[[baz::bar(1, 2)]] void f2(); >>> +[[qux::foo({t})]] void f3(); >>> +[[womp::womp (another::directive (threadprivate (t)))]] void f4(); >>> +[[womp::womp (another::directive (threadprivate (t)))]]; /* { dg-warning "attribute ignored" } */ >> >> If we're ignoring these attributes, we should ignore them everywhere; >> perhaps using them for an attribute-declaration is meaningful in another >> compiler. > > Sounds good. Reminds me of P177, Portable assumptions... > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? > > -- >8 -- > My patch to implement -Wno-attribute=A::b caused a bogus error when > parsing > > [[foo::bar(1, 2)]]; > > when -Wno-attributes=foo::bar was specified on the command line, because > when we create a fake foo::bar attribute and insert it into our attribute > table, it is created with max_length == 0 which doesn't allow any args. > That is wrong -- we know nothing about the attribute, so we shouldn't > require any specific number of arguments. And since unknown attributes > can be rather complex (see for example omp::{directive,sequence}), we > must skip parsing their arguments. To that end, I'm using max_length > with value -2. > > Also let's not warn about things like > > [[vendor::assume(true)]]; > > because they may have some meaning (this is reminiscent of C++ Portable > Assumptions). > > PR c/103649 > > gcc/ChangeLog: > > * attribs.c (handle_ignored_attributes_option): Create the fake > attribute with max_length == -2. > (attribute_ignored_p): New function. > * attribs.h (attribute_ignored_p): Declare. > * tree-core.h (struct attribute_spec): Document that max_length > can be -2. > > gcc/c/ChangeLog: > > * c-decl.c (c_warn_unused_attributes): Don't warn for > attribute_ignored_p. > * c-parser.c (c_parser_std_attribute): Skip parsing of the attribute > arguments when max_length == -2. > > gcc/cp/ChangeLog: > > * parser.c (cp_parser_declaration): Don't warn for attribute_ignored_p. > (cp_parser_std_attribute): Skip parsing of the attribute > arguments when max_length == -2. > > gcc/testsuite/ChangeLog: > > * c-c++-common/Wno-attributes-6.c: New test. > --- > gcc/attribs.c | 20 ++++++++++++++++++- > gcc/attribs.h | 1 + > gcc/c/c-decl.c | 2 +- > gcc/c/c-parser.c | 4 +++- > gcc/cp/parser.c | 6 ++++-- > gcc/testsuite/c-c++-common/Wno-attributes-6.c | 16 +++++++++++++++ > gcc/tree-core.h | 4 +++- > 7 files changed, 47 insertions(+), 6 deletions(-) > create mode 100644 gcc/testsuite/c-c++-common/Wno-attributes-6.c > > diff --git a/gcc/attribs.c b/gcc/attribs.c > index 29703e75fba..82527869093 100644 > --- a/gcc/attribs.c > +++ b/gcc/attribs.c > @@ -304,7 +304,7 @@ handle_ignored_attributes_option (vec *v) > We can't free it here, so squirrel away the pointers. */ > attribute_spec *table = new attribute_spec[2]; > ignored_attributes_table.safe_push (table); > - table[0] = { attr, 0, 0, false, false, false, false, nullptr, nullptr }; > + table[0] = { attr, 0, -2, false, false, false, false, nullptr, nullptr }; > table[1] = { nullptr, 0, 0, false, false, false, false, nullptr, > nullptr }; > register_scoped_attributes (table, IDENTIFIER_POINTER (vendor_id), !attr); > @@ -569,6 +569,24 @@ attr_namespace_ignored_p (tree ns) > return r && r->ignored_p; > } > > +/* Return true if the attribute ATTR should not be warned about. */ > + > +bool > +attribute_ignored_p (tree attr) > +{ > + if (!cxx11_attribute_p (attr)) > + return false; > + if (tree ns = get_attribute_namespace (attr)) > + { > + if (attr_namespace_ignored_p (ns)) > + return true; > + const attribute_spec *as = lookup_attribute_spec (TREE_PURPOSE (attr)); > + if (as && as->max_length == -2) > + return true; > + } > + return false; > +} > + > /* Process the attributes listed in ATTRIBUTES and install them in *NODE, > which is either a DECL (including a TYPE_DECL) or a TYPE. If a DECL, > it should be modified in place; if a TYPE, a copy should be created > diff --git a/gcc/attribs.h b/gcc/attribs.h > index f5899d83c0b..d3449d5bd1d 100644 > --- a/gcc/attribs.h > +++ b/gcc/attribs.h > @@ -39,6 +39,7 @@ extern tree get_attribute_name (const_tree); > extern tree get_attribute_namespace (const_tree); > extern void apply_tm_attr (tree, tree); > extern tree make_attribute (const char *, const char *, tree); > +extern bool attribute_ignored_p (tree); > > extern struct scoped_attributes* register_scoped_attributes (const struct attribute_spec *, > const char *, > diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c > index 4b5481ce8f4..516e3c26e21 100644 > --- a/gcc/c/c-decl.c > +++ b/gcc/c/c-decl.c > @@ -4643,7 +4643,7 @@ c_warn_unused_attributes (tree attrs) > constraint violation. */ > pedwarn (input_location, OPT_Wattributes, "%qE attribute ignored", > get_attribute_name (t)); > - else > + else if (!attribute_ignored_p (t)) > warning (OPT_Wattributes, "%qE attribute ignored", > get_attribute_name (t)); > } > diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c > index d7e5f051ac0..c9068bdbb8a 100644 > --- a/gcc/c/c-parser.c > +++ b/gcc/c/c-parser.c > @@ -4943,7 +4943,9 @@ c_parser_std_attribute (c_parser *parser, bool for_tm) > parens.skip_until_found_close (parser); > return error_mark_node; > } > - if (as) > + /* When MAX_LENGTH is -2, this is a fake attribute created to > + handle -Wno-attributes, and we must skip parsing the arguments. */ > + if (as && as->max_length != -2) > { > bool takes_identifier > = (ns != NULL_TREE > diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c > index 44eed7ea638..a843c953da8 100644 > --- a/gcc/cp/parser.c > +++ b/gcc/cp/parser.c > @@ -14776,7 +14776,7 @@ cp_parser_declaration (cp_parser* parser, tree prefix_attrs) > } > } > > - if (std_attrs != NULL_TREE) > + if (std_attrs != NULL_TREE && !attribute_ignored_p (std_attrs)) > warning_at (make_location (attrs_loc, attrs_loc, parser->lexer), > OPT_Wattributes, "attribute ignored"); > if (cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON)) > @@ -28979,7 +28979,9 @@ cp_parser_std_attribute (cp_parser *parser, tree attr_ns) > /* A GNU attribute that takes an identifier in parameter. */ > attr_flag = id_attr; > > - if (as == NULL) > + /* When MAX_LENGTH is -2, this is a fake attribute created to > + handle -Wno-attributes, and we must skip parsing the arguments. */ > + if (as == NULL || as->max_length == -2) Rather than require multiple places to know about the magic -2, could we have an overload of attribute_ignored_p that takes an attribute_spec*? OK with that change. > { > if ((flag_openmp || flag_openmp_simd) && attr_ns == omp_identifier) > { > diff --git a/gcc/testsuite/c-c++-common/Wno-attributes-6.c b/gcc/testsuite/c-c++-common/Wno-attributes-6.c > new file mode 100644 > index 00000000000..ca3c7bebb99 > --- /dev/null > +++ b/gcc/testsuite/c-c++-common/Wno-attributes-6.c > @@ -0,0 +1,16 @@ > +/* PR c/103649 */ > +/* { dg-do compile { target { c || c++11 } } } */ > +/* { dg-additional-options "-Wno-attributes=foo::bar" } */ > +/* { dg-additional-options "-Wno-attributes=baz::" } */ > +/* { dg-additional-options "-Wno-attributes=womp::womp" } */ > +/* { dg-additional-options "-Wno-attributes=qux::foo" } */ > +/* { dg-additional-options "-Wno-attributes=vendor::assume" } */ > + > +[[vendor::assume(1 + 1 == 2)]]; > +[[foo::bar(1, 2)]]; > +[[baz::bar(1, 2)]]; > +[[foo::bar(1, 2)]] void f1(); > +[[baz::bar(1, 2)]] void f2(); > +[[qux::foo({t})]] void f3(); > +[[womp::womp (another::directive (threadprivate (t)))]] void f4(); > +[[womp::womp (another::directive (threadprivate (t)))]]; > diff --git a/gcc/tree-core.h b/gcc/tree-core.h > index 91ae5237d7e..9b37a065d18 100644 > --- a/gcc/tree-core.h > +++ b/gcc/tree-core.h > @@ -2077,7 +2077,9 @@ struct attribute_spec { > /* The minimum length of the list of arguments of the attribute. */ > int min_length; > /* The maximum length of the list of arguments of the attribute > - (-1 for no maximum). */ > + (-1 for no maximum). It can also be -2 for fake attributes > + created for the sake of -Wno-attributes; in that case, we > + should skip the balanced token sequence when parsing the attribute. */ > int max_length; > /* Whether this attribute requires a DECL. If it does, it will be passed > from types of DECLs, function return types and array element types to > > base-commit: d7ca2a79b82c6500ead6ab983d14c609e2124eee