| Message ID | 20210518210054.916026-1-polacek@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | c++: Relax attribute on friend declaration checking [PR100596] | expand |
On 5/18/21 5:00 PM, Marek Polacek wrote: > It turned out that there are codebases that profusely use GNU attributes > on friend declarations, so we have to dial back our checking and allow > them. And for C++11 attributes let's just warn instead of giving > errors. > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? OK. > PR c++/100596 > > gcc/cp/ChangeLog: > > * cp-tree.h (any_non_type_attribute_p): Remove. > * decl.c (grokdeclarator): Turn an error into a warning and only > warn for standard attributes. > * decl2.c (any_non_type_attribute_p): Remove. > * parser.c (cp_parser_elaborated_type_specifier): Turn an error > into a warning and only warn for standard attributes. > (cp_parser_member_declaration): Likewise. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp0x/friend7.C: Turn a few dg-warnings into dg-errors. > Remove dg-errors for GNU attributes. > * g++.dg/ext/attrib63.C: Remove dg-error. > * g++.dg/cpp0x/friend8.C: New test. > --- > gcc/cp/cp-tree.h | 1 - > gcc/cp/decl.c | 14 +++++++++----- > gcc/cp/decl2.c | 14 -------------- > gcc/cp/parser.c | 29 ++++++++++++++++++---------- > gcc/testsuite/g++.dg/cpp0x/friend7.C | 28 +++++++++++++-------------- > gcc/testsuite/g++.dg/cpp0x/friend8.C | 15 ++++++++++++++ > gcc/testsuite/g++.dg/ext/attrib63.C | 23 +++++++++++++++++++--- > 7 files changed, 77 insertions(+), 47 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/cpp0x/friend8.C > > diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h > index 580db914d40..122dadf976f 100644 > --- a/gcc/cp/cp-tree.h > +++ b/gcc/cp/cp-tree.h > @@ -6763,7 +6763,6 @@ extern tree grokbitfield (const cp_declarator *, cp_decl_specifier_seq *, > tree, tree, tree); > extern tree splice_template_attributes (tree *, tree); > extern bool any_dependent_type_attributes_p (tree); > -extern bool any_non_type_attribute_p (tree); > extern tree cp_reconstruct_complex_type (tree, tree); > extern bool attributes_naming_typedef_ok (tree); > extern void cplus_decl_attributes (tree *, tree, int); > diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c > index 17511f09e79..92fb4a2daea 100644 > --- a/gcc/cp/decl.c > +++ b/gcc/cp/decl.c > @@ -13741,11 +13741,15 @@ grokdeclarator (const cp_declarator *declarator, > > if (friendp) > { > - if (attrlist && !funcdef_flag > - /* Hack to allow attributes like vector_size on a friend. */ > - && any_non_type_attribute_p (*attrlist)) > - error_at (id_loc, "attribute appertains to a friend " > - "declaration that is not a definition"); > + /* Packages tend to use GNU attributes on friends, so we only > + warn for standard attributes. */ > + if (attrlist && !funcdef_flag && cxx11_attribute_p (*attrlist)) > + { > + *attrlist = NULL_TREE; > + if (warning_at (id_loc, OPT_Wattributes, "attribute ignored")) > + inform (id_loc, "an attribute that appertains to a friend " > + "declaration that is not a definition is ignored"); > + } > /* Friends are treated specially. */ > if (ctype == current_class_type) > ; /* We already issued a permerror. */ > diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c > index 8e4dd6b544a..89f874a32cc 100644 > --- a/gcc/cp/decl2.c > +++ b/gcc/cp/decl2.c > @@ -1331,20 +1331,6 @@ any_dependent_type_attributes_p (tree attrs) > return false; > } > > -/* True if ATTRS contains any attribute that does not require a type. */ > - > -bool > -any_non_type_attribute_p (tree attrs) > -{ > - for (tree a = attrs; a; a = TREE_CHAIN (a)) > - { > - const attribute_spec *as = lookup_attribute_spec (get_attribute_name (a)); > - if (as && !as->type_required) > - return true; > - } > - return false; > -} > - > /* Return true iff ATTRS are acceptable attributes to be applied in-place > to a typedef which gives a previously unnamed class or enum a name for > linkage purposes. */ > diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c > index c0b57955954..ac1cefc5c41 100644 > --- a/gcc/cp/parser.c > +++ b/gcc/cp/parser.c > @@ -19774,9 +19774,12 @@ cp_parser_elaborated_type_specifier (cp_parser* parser, > && ! processing_explicit_instantiation) > warning (OPT_Wattributes, > "attributes ignored on template instantiation"); > - else if (is_friend && attributes) > - error ("attribute appertains to a friend declaration that is not " > - "a definition"); > + else if (is_friend && cxx11_attribute_p (attributes)) > + { > + if (warning (OPT_Wattributes, "attribute ignored")) > + inform (input_location, "an attribute that appertains to a friend " > + "declaration that is not a definition is ignored"); > + } > else if (is_declaration && cp_parser_declares_only_class_p (parser)) > cplus_decl_attributes (&type, attributes, (int) ATTR_FLAG_TYPE_IN_PLACE); > else > @@ -26064,17 +26067,23 @@ cp_parser_member_declaration (cp_parser* parser) > if (type && TREE_CODE (type) == TYPE_DECL) > type = TREE_TYPE (type); > } > + /* Warn if an attribute cannot appear here, as per > + [dcl.attr.grammar]/5. But not when declares_class_or_enum: > + we ignore attributes in elaborated-type-specifiers. */ > + if (!declares_class_or_enum > + && cxx11_attribute_p (decl_specifiers.attributes)) > + { > + decl_specifiers.attributes = NULL_TREE; > + if (warning_at (decl_spec_token_start->location, > + OPT_Wattributes, "attribute ignored")) > + inform (decl_spec_token_start->location, "an attribute " > + "that appertains to a friend declaration that " > + "is not a definition is ignored"); > + } > if (!type || !TYPE_P (type)) > error_at (decl_spec_token_start->location, > "friend declaration does not name a class or " > "function"); > - /* Give an error if an attribute cannot appear here, as per > - [dcl.attr.grammar]/5. But not when declares_class_or_enum: > - we ignore attributes in elaborated-type-specifiers. */ > - else if (!declares_class_or_enum && decl_specifiers.attributes) > - error_at (decl_spec_token_start->location, > - "attribute appertains to a friend declaration " > - "that is not a definition"); > else > make_friend_class (current_class_type, type, > /*complain=*/true); > diff --git a/gcc/testsuite/g++.dg/cpp0x/friend7.C b/gcc/testsuite/g++.dg/cpp0x/friend7.C > index 734b367cd2b..e1d5f449f5c 100644 > --- a/gcc/testsuite/g++.dg/cpp0x/friend7.C > +++ b/gcc/testsuite/g++.dg/cpp0x/friend7.C > @@ -6,21 +6,21 @@ template<typename T1, typename T2> > void foo (T1, T2); > > struct S { > - [[deprecated]] friend void f(); // { dg-error "attribute appertains" } > + [[deprecated]] friend void f(); // { dg-warning "attribute ignored" } > [[deprecated]] friend void f2() { } > - __attribute__((deprecated)) friend void f3(); // { dg-error "attribute appertains" } > - friend void f3 [[deprecated]] (); // { dg-error "attribute appertains" } > + __attribute__((deprecated)) friend void f3(); > + friend void f3 [[deprecated]] (); // { dg-warning "attribute ignored" } > friend void f4 [[deprecated]] () { } > - [[deprecated]] friend void; // { dg-error "attribute appertains" } > - __attribute__((deprecated)) friend int; // { dg-error "attribute appertains" } > - friend __attribute__((deprecated)) int; // { dg-error "attribute appertains" } > - friend int __attribute__((deprecated)); // { dg-error "attribute appertains" } > - [[deprecated]] friend X; // { dg-error "attribute appertains" } > + [[deprecated]] friend void; // { dg-warning "attribute ignored" } > + __attribute__((deprecated)) friend int; > + friend __attribute__((deprecated)) int; > + friend int __attribute__((deprecated)); > + [[deprecated]] friend X; // { dg-warning "attribute ignored" } > [[deprecated]] friend class N; // { dg-warning "attribute ignored" } > - friend class [[deprecated]] N2; // { dg-error "attribute appertains" } > - friend class __attribute__((deprecated)) N3; // { dg-error "attribute appertains" } > - [[deprecated]] friend void foo<>(int, int); // { dg-error "attribute appertains" } > - [[deprecated]] friend void ::foo(int, int); // { dg-error "attribute appertains" } > + friend class [[deprecated]] N2; // { dg-warning "attribute ignored" } > + friend class __attribute__((deprecated)) N3; > + [[deprecated]] friend void foo<>(int, int); // { dg-warning "attribute ignored" } > + [[deprecated]] friend void ::foo(int, int); // { dg-warning "attribute ignored" } > // { dg-bogus "should have" "PR100339" { xfail *-*-* } .-1 } > }; > > @@ -29,12 +29,12 @@ class node { }; > > template<typename T> > struct A { > - [[deprecated]] friend T; // { dg-error "attribute appertains" } > + [[deprecated]] friend T; // { dg-warning "attribute ignored" } > [[deprecated]] friend class node<T>; // { dg-warning "attribute ignored" } > template<typename> > [[deprecated]] friend class A; // { dg-warning "attribute ignored" } > template<typename> > [[deprecated]] friend void bar () { } > template<typename> > - [[deprecated]] friend void baz (); // { dg-error "attribute appertains" } > + [[deprecated]] friend void baz (); // { dg-warning "attribute ignored" } > }; > diff --git a/gcc/testsuite/g++.dg/cpp0x/friend8.C b/gcc/testsuite/g++.dg/cpp0x/friend8.C > new file mode 100644 > index 00000000000..8d2a2d35d54 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp0x/friend8.C > @@ -0,0 +1,15 @@ > +// PR c++/100596 > +// { dg-do compile { target c++11 } } > + > +struct A > +{ > + __attribute((deprecated)) friend void f(A); // part of A API, definition in .C > + [[deprecated]] friend void f2(A); // { dg-warning "ignored" } > +}; > + > +int main() > +{ > + A a; > + f(a); // { dg-warning "is deprecated" } > + f2(a); > +} > diff --git a/gcc/testsuite/g++.dg/ext/attrib63.C b/gcc/testsuite/g++.dg/ext/attrib63.C > index 93bde1e7d72..583779a9159 100644 > --- a/gcc/testsuite/g++.dg/ext/attrib63.C > +++ b/gcc/testsuite/g++.dg/ext/attrib63.C > @@ -4,9 +4,9 @@ > #define vector __attribute__((vector_size(16))) > class A { > friend vector float f(); > - __attribute__((deprecated)) friend void f2(); // { dg-error "attribute appertains" } > - friend __attribute__((deprecated, vector_size(16))) float f3(); // { dg-error "attribute appertains" } > - friend __attribute__((vector_size(16), deprecated)) float f4(); // { dg-error "attribute appertains" } > + __attribute__((deprecated)) friend void f2(); > + friend __attribute__((deprecated, vector_size(16))) float f3(); > + friend __attribute__((vector_size(16), deprecated)) float f4(); > }; > > vector float vf; > @@ -15,3 +15,20 @@ f () > { > return vf; > } > + > +void > +f2 () > +{ > +} > + > +vector float > +f3 () > +{ > + return vf; > +} > + > +vector float > +f4 () > +{ > + return vf; > +} > > base-commit: 8c114759b8c9c9e2ec90b82d92a24b5a71647017 >
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h index 580db914d40..122dadf976f 100644 --- a/gcc/cp/cp-tree.h +++ b/gcc/cp/cp-tree.h @@ -6763,7 +6763,6 @@ extern tree grokbitfield (const cp_declarator *, cp_decl_specifier_seq *, tree, tree, tree); extern tree splice_template_attributes (tree *, tree); extern bool any_dependent_type_attributes_p (tree); -extern bool any_non_type_attribute_p (tree); extern tree cp_reconstruct_complex_type (tree, tree); extern bool attributes_naming_typedef_ok (tree); extern void cplus_decl_attributes (tree *, tree, int); diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c index 17511f09e79..92fb4a2daea 100644 --- a/gcc/cp/decl.c +++ b/gcc/cp/decl.c @@ -13741,11 +13741,15 @@ grokdeclarator (const cp_declarator *declarator, if (friendp) { - if (attrlist && !funcdef_flag - /* Hack to allow attributes like vector_size on a friend. */ - && any_non_type_attribute_p (*attrlist)) - error_at (id_loc, "attribute appertains to a friend " - "declaration that is not a definition"); + /* Packages tend to use GNU attributes on friends, so we only + warn for standard attributes. */ + if (attrlist && !funcdef_flag && cxx11_attribute_p (*attrlist)) + { + *attrlist = NULL_TREE; + if (warning_at (id_loc, OPT_Wattributes, "attribute ignored")) + inform (id_loc, "an attribute that appertains to a friend " + "declaration that is not a definition is ignored"); + } /* Friends are treated specially. */ if (ctype == current_class_type) ; /* We already issued a permerror. */ diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c index 8e4dd6b544a..89f874a32cc 100644 --- a/gcc/cp/decl2.c +++ b/gcc/cp/decl2.c @@ -1331,20 +1331,6 @@ any_dependent_type_attributes_p (tree attrs) return false; } -/* True if ATTRS contains any attribute that does not require a type. */ - -bool -any_non_type_attribute_p (tree attrs) -{ - for (tree a = attrs; a; a = TREE_CHAIN (a)) - { - const attribute_spec *as = lookup_attribute_spec (get_attribute_name (a)); - if (as && !as->type_required) - return true; - } - return false; -} - /* Return true iff ATTRS are acceptable attributes to be applied in-place to a typedef which gives a previously unnamed class or enum a name for linkage purposes. */ diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c index c0b57955954..ac1cefc5c41 100644 --- a/gcc/cp/parser.c +++ b/gcc/cp/parser.c @@ -19774,9 +19774,12 @@ cp_parser_elaborated_type_specifier (cp_parser* parser, && ! processing_explicit_instantiation) warning (OPT_Wattributes, "attributes ignored on template instantiation"); - else if (is_friend && attributes) - error ("attribute appertains to a friend declaration that is not " - "a definition"); + else if (is_friend && cxx11_attribute_p (attributes)) + { + if (warning (OPT_Wattributes, "attribute ignored")) + inform (input_location, "an attribute that appertains to a friend " + "declaration that is not a definition is ignored"); + } else if (is_declaration && cp_parser_declares_only_class_p (parser)) cplus_decl_attributes (&type, attributes, (int) ATTR_FLAG_TYPE_IN_PLACE); else @@ -26064,17 +26067,23 @@ cp_parser_member_declaration (cp_parser* parser) if (type && TREE_CODE (type) == TYPE_DECL) type = TREE_TYPE (type); } + /* Warn if an attribute cannot appear here, as per + [dcl.attr.grammar]/5. But not when declares_class_or_enum: + we ignore attributes in elaborated-type-specifiers. */ + if (!declares_class_or_enum + && cxx11_attribute_p (decl_specifiers.attributes)) + { + decl_specifiers.attributes = NULL_TREE; + if (warning_at (decl_spec_token_start->location, + OPT_Wattributes, "attribute ignored")) + inform (decl_spec_token_start->location, "an attribute " + "that appertains to a friend declaration that " + "is not a definition is ignored"); + } if (!type || !TYPE_P (type)) error_at (decl_spec_token_start->location, "friend declaration does not name a class or " "function"); - /* Give an error if an attribute cannot appear here, as per - [dcl.attr.grammar]/5. But not when declares_class_or_enum: - we ignore attributes in elaborated-type-specifiers. */ - else if (!declares_class_or_enum && decl_specifiers.attributes) - error_at (decl_spec_token_start->location, - "attribute appertains to a friend declaration " - "that is not a definition"); else make_friend_class (current_class_type, type, /*complain=*/true); diff --git a/gcc/testsuite/g++.dg/cpp0x/friend7.C b/gcc/testsuite/g++.dg/cpp0x/friend7.C index 734b367cd2b..e1d5f449f5c 100644 --- a/gcc/testsuite/g++.dg/cpp0x/friend7.C +++ b/gcc/testsuite/g++.dg/cpp0x/friend7.C @@ -6,21 +6,21 @@ template<typename T1, typename T2> void foo (T1, T2); struct S { - [[deprecated]] friend void f(); // { dg-error "attribute appertains" } + [[deprecated]] friend void f(); // { dg-warning "attribute ignored" } [[deprecated]] friend void f2() { } - __attribute__((deprecated)) friend void f3(); // { dg-error "attribute appertains" } - friend void f3 [[deprecated]] (); // { dg-error "attribute appertains" } + __attribute__((deprecated)) friend void f3(); + friend void f3 [[deprecated]] (); // { dg-warning "attribute ignored" } friend void f4 [[deprecated]] () { } - [[deprecated]] friend void; // { dg-error "attribute appertains" } - __attribute__((deprecated)) friend int; // { dg-error "attribute appertains" } - friend __attribute__((deprecated)) int; // { dg-error "attribute appertains" } - friend int __attribute__((deprecated)); // { dg-error "attribute appertains" } - [[deprecated]] friend X; // { dg-error "attribute appertains" } + [[deprecated]] friend void; // { dg-warning "attribute ignored" } + __attribute__((deprecated)) friend int; + friend __attribute__((deprecated)) int; + friend int __attribute__((deprecated)); + [[deprecated]] friend X; // { dg-warning "attribute ignored" } [[deprecated]] friend class N; // { dg-warning "attribute ignored" } - friend class [[deprecated]] N2; // { dg-error "attribute appertains" } - friend class __attribute__((deprecated)) N3; // { dg-error "attribute appertains" } - [[deprecated]] friend void foo<>(int, int); // { dg-error "attribute appertains" } - [[deprecated]] friend void ::foo(int, int); // { dg-error "attribute appertains" } + friend class [[deprecated]] N2; // { dg-warning "attribute ignored" } + friend class __attribute__((deprecated)) N3; + [[deprecated]] friend void foo<>(int, int); // { dg-warning "attribute ignored" } + [[deprecated]] friend void ::foo(int, int); // { dg-warning "attribute ignored" } // { dg-bogus "should have" "PR100339" { xfail *-*-* } .-1 } }; @@ -29,12 +29,12 @@ class node { }; template<typename T> struct A { - [[deprecated]] friend T; // { dg-error "attribute appertains" } + [[deprecated]] friend T; // { dg-warning "attribute ignored" } [[deprecated]] friend class node<T>; // { dg-warning "attribute ignored" } template<typename> [[deprecated]] friend class A; // { dg-warning "attribute ignored" } template<typename> [[deprecated]] friend void bar () { } template<typename> - [[deprecated]] friend void baz (); // { dg-error "attribute appertains" } + [[deprecated]] friend void baz (); // { dg-warning "attribute ignored" } }; diff --git a/gcc/testsuite/g++.dg/cpp0x/friend8.C b/gcc/testsuite/g++.dg/cpp0x/friend8.C new file mode 100644 index 00000000000..8d2a2d35d54 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/friend8.C @@ -0,0 +1,15 @@ +// PR c++/100596 +// { dg-do compile { target c++11 } } + +struct A +{ + __attribute((deprecated)) friend void f(A); // part of A API, definition in .C + [[deprecated]] friend void f2(A); // { dg-warning "ignored" } +}; + +int main() +{ + A a; + f(a); // { dg-warning "is deprecated" } + f2(a); +} diff --git a/gcc/testsuite/g++.dg/ext/attrib63.C b/gcc/testsuite/g++.dg/ext/attrib63.C index 93bde1e7d72..583779a9159 100644 --- a/gcc/testsuite/g++.dg/ext/attrib63.C +++ b/gcc/testsuite/g++.dg/ext/attrib63.C @@ -4,9 +4,9 @@ #define vector __attribute__((vector_size(16))) class A { friend vector float f(); - __attribute__((deprecated)) friend void f2(); // { dg-error "attribute appertains" } - friend __attribute__((deprecated, vector_size(16))) float f3(); // { dg-error "attribute appertains" } - friend __attribute__((vector_size(16), deprecated)) float f4(); // { dg-error "attribute appertains" } + __attribute__((deprecated)) friend void f2(); + friend __attribute__((deprecated, vector_size(16))) float f3(); + friend __attribute__((vector_size(16), deprecated)) float f4(); }; vector float vf; @@ -15,3 +15,20 @@ f () { return vf; } + +void +f2 () +{ +} + +vector float +f3 () +{ + return vf; +} + +vector float +f4 () +{ + return vf; +}