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Fri, 17 Dec 2021 10:14:54 -0800 (PST) X-Google-Smtp-Source: ABdhPJxHFVf5EJrYm2BmoTI+916dOgJO8IbtZPvJE/WqYEgppXVUDFhee4jlIReshVHwo1KoFwNmaQ== X-Received: by 2002:a05:6214:194f:: with SMTP id q15mr3443592qvk.73.1639764894605; Fri, 17 Dec 2021 10:14:54 -0800 (PST) Received: from redhat.com ([2601:184:4780:4310::aac2]) by smtp.gmail.com with ESMTPSA id t18sm7833663qtw.64.2021.12.17.10.14.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 17 Dec 2021 10:14:53 -0800 (PST) Date: Fri, 17 Dec 2021 13:14:51 -0500 To: Jason Merrill Subject: [PATCH v3] attribs: Fix wrong error with -Wno-attribute=A::b [PR103649] Message-ID: References: <20211216223555.820800-1-polacek@redhat.com> <20211216225346.GA2646553@tucnak> <7d088a03-cddc-9287-aae1-e32532a21f12@redhat.com> MIME-Version: 1.0 In-Reply-To: <7d088a03-cddc-9287-aae1-e32532a21f12@redhat.com> User-Agent: Mutt/2.1.3 (2021-09-10) X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline X-Spam-Status: No, score=-13.3 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, 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-Patchwork-Original-From: Marek Polacek via Gcc-patches From: Marek Polacek Reply-To: Marek Polacek Cc: Jakub Jelinek , GCC Patches , Joseph Myers Errors-To: gcc-patches-bounces+incoming=patchwork.ozlabs.org@gcc.gnu.org Sender: "Gcc-patches" 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 base-commit: d7ca2a79b82c6500ead6ab983d14c609e2124eee 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) { 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