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* [gcc r12-925] c++: Relax attribute on friend declaration checking [PR100596]
@ 2021-05-19 17:10 Marek Polacek
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From: Marek Polacek @ 2021-05-19 17:10 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:adcb497bdba499d161d2e5e8de782bdd6f75d62c
commit r12-925-gadcb497bdba499d161d2e5e8de782bdd6f75d62c
Author: Marek Polacek <polacek@redhat.com>
Date: Tue May 18 16:11:16 2021 -0400
c++: Relax attribute on friend declaration checking [PR100596]
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.
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.
Diff:
---
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(-)
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 3c900dc08f7..860ed795299 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -6761,7 +6761,6 @@ 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 4f2fc2e496e..28052df9f45 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -13731,11 +13731,15 @@ 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 f3503b13a5a..bc0505df502 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;
+}
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