[PATCH] PR c++/77306 - Unable to specify visibility for explicit template instantiations

[James Abbatiello]

This is my first time attempting a contribution here so please point
out any mistakes.  I've tested this on x86_64-pc-linux-gnu in a VM.

-- 
James Abbatiello


gcc/ChangeLog:

        PR c++/77306
        * attribs.c (decl_attributes): Allow visibility attributes on explicit
        template instantiations.
        * gcc-family/c-attribs.c (handle_visibility_attribute): Likewise.
---
 gcc/attribs.c                               | 3 ++-
 gcc/c-family/c-attribs.c                    | 6 ------
 gcc/testsuite/g++.dg/ext/visibility/warn4.C | 5 +++--
 3 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/gcc/attribs.c b/gcc/attribs.c
index 55b21271b39..ed1cfa1765b 100644
--- a/gcc/attribs.c
+++ b/gcc/attribs.c
@@ -534,7 +534,8 @@ decl_attributes (tree *node, tree attributes, int flags)
 
       if (TYPE_P (*anode)
          && (flags & (int) ATTR_FLAG_TYPE_IN_PLACE)
-         && TYPE_SIZE (*anode) != NULL_TREE)
+         && TYPE_SIZE (*anode) != NULL_TREE
+         && !is_attribute_p ("visibility", name))
        {
          warning (OPT_Wattributes, "type attributes ignored after type is 
already defined");
          continue;
diff --git a/gcc/c-family/c-attribs.c b/gcc/c-family/c-attribs.c
index f2a88e147ba..e3fb82aef21 100644
--- a/gcc/c-family/c-attribs.c
+++ b/gcc/c-family/c-attribs.c
@@ -1895,12 +1895,6 @@ handle_visibility_attribute (tree *node, tree name, tree 
args,
                   name);
          return NULL_TREE;
        }
-      else if (TYPE_FIELDS (*node))
-       {
-         error ("%qE attribute ignored because %qT is already defined",
-                name, *node);
-         return NULL_TREE;
-       }
     }
   else if (decl_function_context (decl) != 0 || !TREE_PUBLIC (decl))
     {
diff --git a/gcc/testsuite/g++.dg/ext/visibility/warn4.C 
b/gcc/testsuite/g++.dg/ext/visibility/warn4.C
index 33e6f678592..a55f9682a12 100644
--- a/gcc/testsuite/g++.dg/ext/visibility/warn4.C
+++ b/gcc/testsuite/g++.dg/ext/visibility/warn4.C
@@ -1,10 +1,11 @@
-// Warn if we try to give an instantiation visibility after it's already
+// Don't warn if we give an instantiation visibility after it's already
 // been instantiated.
 
 // { dg-require-visibility "" }
+// { dg-final { scan-hidden "_ZN1AIdE1fEd" } }
 
 template <class T> struct A { void f (T); };
 template <class T> void A<T>::f (T) { }
 
 A<double> ad;
-template struct __attribute ((visibility ("hidden"))) A<double>; // { 
dg-warning "already defined" }
+template struct __attribute ((visibility ("hidden"))) A<double>;
-- 
2.11.0