Am 2021-05-14 um 00:08 schrieb Marek Polacek via Gcc-patches:
On Wed, May 12, 2021 at 08:27:18PM -0400, Jason Merrill wrote:
On 5/12/21 8:03 PM, Marek Polacek wrote:
diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index 89f874a32cc..2bcefb619aa 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -1331,6 +1331,20 @@ any_dependent_type_attributes_p (tree attrs)
return false;
}
+/* True if ATTRS contains any attribute that requires a type. */
Let's invert this to check if ATTRS contains any attribute that does *not*
require a type, and would therefore apply to the decl.
Sounds good, done. Now I don't need to check *attrlist.
I've also fixed up the xfail thing in my new test.
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
-- >8 --
This patch implements [dcl.attr.grammar]/5: "If an attribute-specifier-seq
appertains to a friend declaration ([class.friend]), that declaration shall
be a definition."
This restriction applies to C++11-style attributes as well as GNU
attributes with the exception that we allow GNU attributes that require
a type, such as vector_size to continue accepting code as in attrib63.C.
There are various forms of friend declarations, we have friend
templates, C++11 extended friend declarations, and so on. In some cases
we already ignore the attribute and warn that it was ignored. But
certain cases weren't diagnosed, and with this patch we'll give a hard
error. I tried hard not to emit both a warning and error and I think it
worked out.
Jason provided the cp_parser_decl_specifier_seq hunk to detect using
standard attributes in the middle of decl-specifiers, which is invalid.
Co-authored-by: Jason Merrill <ja...@redhat.com>
gcc/cp/ChangeLog:
PR c++/99032
* cp-tree.h (any_non_type_attribute_p): Declare.
* decl.c (grokdeclarator): Diagnose when an attribute appertains to
a friend declaration that is not a definition.
* decl2.c (any_non_type_attribute_p): New.
* parser.c (cp_parser_decl_specifier_seq): Diagnose standard attributes
in the middle of decl-specifiers.
(cp_parser_elaborated_type_specifier): Diagnose when an attribute
appertains to a friend declaration that is not a definition.
(cp_parser_member_declaration): Likewise.
Hi,
I haven't investigated it in detail yet, but it seems this change breaks
building Qt-based (tested with Qt-5.12.7) applications. Sample error
output with trunk@r12+876 -std=gnu++14:
/usr/include/qt5/QtCore/qvariant.h:470:33: error: attribute appertains
to a friend declaration that is not a definition
friend Q_CORE_EXPORT QDebug operator<<(QDebug, const QVariant &);
^~~~~~~~
For GCC Q_CORE_EXPORT is defined (via Q_DECL_EXPORT) to
__attribute__((visibility("default"))) AFAICS.
As this error seemingly cannot be turned into a warning, it's probably
quite a problem for many people.
regards,
Franz
