On 02/14/2012 08:50 PM, Jason Merrill wrote:
While looking at PR 51930, I discovered that we were silently ignoring
attributes on explicit instantiations; this patch warns about this. This
isn't exactly a regression, but the submitter ran into it as a result of
a behavior change in 4.7, and the patch is extremely safe, so I think it
should go in.
It turns out that we already had a warning for this situation that also
gives a suggestion for how to deal with it, so I'm going to make that
warning apply to this case as well.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit fc93bb109ba5d22a5c08ee026d572436a999bdef
Author: Jason Merrill <ja...@redhat.com>
Date: Wed Feb 29 21:51:33 2012 -0500
PR c++/51930
* decl.c (check_tag_decl): Move warning for misplaced attributes here.
(shadow_tag): From here.
* parser.c (cp_parser_explicit_instantiation): Don't warn here.
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 2a6a516..c47f87c 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -4216,6 +4216,19 @@ check_tag_decl (cp_decl_specifier_seq *declspecs)
error ("%<constexpr%> cannot be used for type declarations");
}
+ if (declspecs->attributes)
+ {
+ location_t loc = input_location;
+ if (!CLASSTYPE_TEMPLATE_INSTANTIATION (declared_type))
+ /* For a non-template class, use the name location; for a template
+ class (an explicit instantiation), use the current location. */
+ input_location = location_of (declared_type);
+ warning (0, "attribute ignored in declaration of %q#T", declared_type);
+ warning (0, "attribute for %q#T must follow the %qs keyword",
+ declared_type, class_key_or_enum_as_string (declared_type));
+ input_location = loc;
+ }
+
return declared_type;
}
@@ -4240,14 +4253,6 @@ shadow_tag (cp_decl_specifier_seq *declspecs)
if (!t)
return NULL_TREE;
- if (declspecs->attributes)
- {
- warning (0, "attribute ignored in declaration of %q+#T", t);
- warning (0, "attribute for %q+#T must follow the %qs keyword",
- t, class_key_or_enum_as_string (t));
-
- }
-
if (maybe_process_partial_specialization (t) == error_mark_node)
return NULL_TREE;
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 3e2be97..491f48e 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -13122,9 +13122,6 @@ cp_parser_explicit_instantiation (cp_parser* parser)
tree type;
type = check_tag_decl (&decl_specifiers);
- if (decl_specifiers.attributes)
- warning (OPT_Wattributes,
- "attributes ignored on explicit type instantiation");
/* Turn access control back on for names used during
template instantiation. */
pop_deferring_access_checks ();
diff --git a/gcc/testsuite/g++.dg/ext/attrib43.C b/gcc/testsuite/g++.dg/ext/attrib43.C
index fe9f072..acae3f2 100644
--- a/gcc/testsuite/g++.dg/ext/attrib43.C
+++ b/gcc/testsuite/g++.dg/ext/attrib43.C
@@ -2,4 +2,4 @@ template <class T> struct A { };
template
__attribute__ ((packed))
-struct A<int>; // { dg-warning "attributes ignored" }
+struct A<int>; // { dg-warning "attribute" }
