On Fri, Dec 08, 2023 at 12:06:01PM -0500, Jason Merrill wrote: > > @@ -21111,7 +21116,7 @@ cp_parser_elaborated_type_specifier (cp_ > > } > > else if (is_declaration && cp_parser_declares_only_class_p (parser)) > > cplus_decl_attributes (&type, attributes, (int) > > ATTR_FLAG_TYPE_IN_PLACE); > > - else > > + else if (any_nonignored_attribute_p (attributes)) > > warning (OPT_Wattributes, > > "attributes ignored on elaborated-type-specifier that is " > > "not a forward declaration"); > > I believe this is also prohibited by > https://eel.is/c++draft/dcl.type.elab#3
You're right and there is also https://eel.is/c++draft/temp.spec#temp.explicit-3 which prohibits it for explicit template instantiations. > so I would leave all the warnings in this function alone. Ok. > > location_t attr_loc = declspecs->locations[ds_std_attribute]; > > - if (warning_at (attr_loc, OPT_Wattributes, "attribute ignored")) > > + if (any_nonignored_attribute_p (declspecs->std_attributes) > > + && warning_at (attr_loc, OPT_Wattributes, "attribute ignored")) > > inform (attr_loc, "an attribute that appertains to a type-specifier " > > "is ignored"); > > } > > This seems untested, e.g. > > int [[foo::bar]] i; Thanks. Here is an updated patch, so far tested with GXX_TESTSUITE_STDS=98,11,14,17,20,23,26 make check-g++ RUNTESTFLAGS="dg.exp='Wno-attributes*' ubsan.exp=Wno-attributes*" Ok for trunk if it passes full bootstrap/regtest? 2023-12-08 Jakub Jelinek <ja...@redhat.com> gcc/ * attribs.h (any_nonignored_attribute_p): Declare. * attribs.cc (any_nonignored_attribute_p): New function. gcc/cp/ * parser.cc (cp_parser_statement, cp_parser_expression_statement, cp_parser_declaration, cp_parser_asm_definition): Don't diagnose ignored attributes if !any_nonignored_attribute_p. * decl.cc (grokdeclarator): Likewise. * name-lookup.cc (handle_namespace_attrs, finish_using_directive): Don't diagnose ignoring of attr_ignored_p attributes. gcc/testsuite/ * g++.dg/warn/Wno-attributes-1.C: New test. --- gcc/attribs.h.jj 2023-12-06 12:03:27.421176109 +0100 +++ gcc/attribs.h 2023-12-06 12:36:55.704884514 +0100 @@ -48,6 +48,7 @@ extern void apply_tm_attr (tree, tree); extern tree make_attribute (const char *, const char *, tree); extern bool attribute_ignored_p (tree); extern bool attribute_ignored_p (const attribute_spec *const); +extern bool any_nonignored_attribute_p (tree); extern struct scoped_attributes * register_scoped_attributes (const scoped_attribute_specs &, bool = false); --- gcc/attribs.cc.jj 2023-12-06 12:03:27.386176602 +0100 +++ gcc/attribs.cc 2023-12-06 12:36:55.704884514 +0100 @@ -584,6 +584,19 @@ attribute_ignored_p (const attribute_spe return as->max_length == -2; } +/* Return true if the ATTRS chain contains at least one attribute which + is not ignored. */ + +bool +any_nonignored_attribute_p (tree attrs) +{ + for (tree attr = attrs; attr; attr = TREE_CHAIN (attr)) + if (!attribute_ignored_p (attr)) + return true; + + return false; +} + /* See whether LIST contains at least one instance of attribute ATTR (possibly with different arguments). Return the first such attribute if so, otherwise return null. */ --- gcc/cp/parser.cc.jj 2023-12-06 12:03:27.502174967 +0100 +++ gcc/cp/parser.cc 2023-12-06 12:36:55.704884514 +0100 @@ -12778,9 +12778,8 @@ cp_parser_statement (cp_parser* parser, SET_EXPR_LOCATION (statement, statement_location); /* Allow "[[fallthrough]];" or "[[assume(cond)]];", but warn otherwise. */ - if (std_attrs != NULL_TREE) - warning_at (attrs_loc, - OPT_Wattributes, + if (std_attrs != NULL_TREE && any_nonignored_attribute_p (std_attrs)) + warning_at (attrs_loc, OPT_Wattributes, "attributes at the beginning of statement are ignored"); } @@ -12986,7 +12985,7 @@ cp_parser_expression_statement (cp_parse } /* Allow "[[fallthrough]];", but warn otherwise. */ - if (attr != NULL_TREE) + if (attr != NULL_TREE && any_nonignored_attribute_p (attr)) warning_at (loc, OPT_Wattributes, "attributes at the beginning of statement are ignored"); @@ -15191,7 +15190,7 @@ cp_parser_declaration (cp_parser* parser } } - if (std_attrs != NULL_TREE && !attribute_ignored_p (std_attrs)) + if (std_attrs != NULL_TREE && any_nonignored_attribute_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)) @@ -22672,7 +22671,7 @@ cp_parser_asm_definition (cp_parser* par symtab->finalize_toplevel_asm (string); } - if (std_attrs) + if (std_attrs && any_nonignored_attribute_p (std_attrs)) warning_at (asm_loc, OPT_Wattributes, "attributes ignored on %<asm%> declaration"); } --- gcc/cp/decl.cc.jj 2023-12-06 12:03:27.483175235 +0100 +++ gcc/cp/decl.cc 2023-12-06 12:36:55.698884598 +0100 @@ -13058,7 +13058,8 @@ grokdeclarator (const cp_declarator *dec && !diagnose_misapplied_contracts (declspecs->std_attributes)) { location_t attr_loc = declspecs->locations[ds_std_attribute]; - if (warning_at (attr_loc, OPT_Wattributes, "attribute ignored")) + if (any_nonignored_attribute_p (declspecs->std_attributes) + && warning_at (attr_loc, OPT_Wattributes, "attribute ignored")) inform (attr_loc, "an attribute that appertains to a type-specifier " "is ignored"); } --- gcc/cp/name-lookup.cc.jj 2023-12-06 12:03:27.495175066 +0100 +++ gcc/cp/name-lookup.cc 2023-12-06 12:36:55.695884641 +0100 @@ -6356,7 +6356,7 @@ handle_namespace_attrs (tree ns, tree at DECL_ATTRIBUTES (ns) = tree_cons (name, args, DECL_ATTRIBUTES (ns)); } - else + else if (!attribute_ignored_p (d)) { warning (OPT_Wattributes, "%qD attribute directive ignored", name); @@ -8703,7 +8703,7 @@ finish_using_directive (tree target, tre diagnosed = true; } } - else + else if (!attribute_ignored_p (a)) warning (OPT_Wattributes, "%qD attribute directive ignored", name); } } --- gcc/testsuite/g++.dg/warn/Wno-attributes-1.C.jj 2023-12-06 14:27:29.006249075 +0100 +++ gcc/testsuite/g++.dg/warn/Wno-attributes-1.C 2023-12-08 18:50:36.077628959 +0100 @@ -0,0 +1,52 @@ +// { dg-do compile { target c++11 } } +// { dg-options "-Wno-attributes=bar:: -Wno-attributes=baz::qux" } + +[[foo::bar]]; // { dg-warning "attribute ignored" } +[[bar::foo, foo::bar, baz::qux]]; // { dg-warning "attribute ignored" } +[[bar::foo, bar::bar, baz::qux]]; // { dg-bogus "attribute ignored" } + +namespace [[foo::bar]] N { // { dg-warning "'bar' attribute directive ignored" } + int n; +} +namespace [[bar::foo, foo::bar, baz::qux]] O { // { dg-warning "'bar' attribute directive ignored" } + int o; +} +namespace [[bar::foo, bar::bar, baz::qux]] P { // { dg-bogus "attribute directive ignored" } + int p; +} + +void +foo () +{ + int i = 0; + [[foo::bar]]; // { dg-warning "attributes at the beginning of statement are ignored" } + [[bar::foo, foo::bar, baz::qux]]; // { dg-warning "attributes at the beginning of statement are ignored" } + [[bar::foo, bar::bar, baz::qux]]; // { dg-bogus "attributes at the beginning of statement are ignored" } + [[foo::bar]] ++i; // { dg-warning "attributes at the beginning of statement are ignored" } + [[bar::foo, foo::bar, baz::qux]] ++i; // { dg-warning "attributes at the beginning of statement are ignored" } + [[bar::foo, bar::bar, baz::qux]] ++i; // { dg-bogus "attributes at the beginning of statement are ignored" } + [[foo::bar]] asm (""); // { dg-warning "attributes ignored on 'asm' declaration" } + [[bar::foo, foo::bar, baz::qux]] asm (""); // { dg-warning "attributes ignored on 'asm' declaration" } + [[bar::foo, bar::bar, baz::qux]] asm (""); // { dg-bogus "attributes ignored on 'asm' declaration" } + [[foo::bar]] using namespace N; // { dg-warning "'bar' attribute directive ignored" } + [[bar::foo, foo::bar, baz::qux]] using namespace O; // { dg-warning "'bar' attribute directive ignored" } + [[bar::foo, bar::bar, baz::qux]] using namespace P; // { dg-bogus "attribute directive ignored" } +} + +class S +{ + [[foo::bar]] friend int bar (S &); // { dg-warning "attribute ignored" } + // { dsg-message "an attribute that appertains to a friend declaration that is not a definition is ignored" "" { target *-*-* } .-1 } + [[bar::foo, foo::bar, baz::qux]] friend int baz (S &); // { dg-warning "attribute ignored" } + // { dsg-message "an attribute that appertains to a friend declaration that is not a definition is ignored" "" { target *-*-* } .-1 } + [[bar::foo, bar::bar, baz::qux]] friend int qux (S &); // { dg-warning "attribute ignored" } + // { dsg-message "an attribute that appertains to a friend declaration that is not a definition is ignored" "" { target *-*-* } .-1 } +public: + int s; +}; + +int [[foo::bar]] i; // { dg-warning "attribute ignored" } + // { dg-message "an attribute that appertains to a type-specifier is ignored" "" { target *-*-* } .-1 } +int [[bar::foo, foo::bar, baz::qux]] j; // { dg-warning "attribute ignored" } + // { dg-message "an attribute that appertains to a type-specifier is ignored" "" { target *-*-* } .-1 } +int [[bar::foo, bar::bar, baz::qux]] k; // { dg-bogus "attribute ignored" } Jakub
