From 5b1cbe1453663b9abd6df089c2882071f2335fb2 Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@redhat.com>
Date: Thu, 14 Jan 2010 23:41:02 +0100
Subject: [PATCH] re PR c++/42608 (Undefined reference not reported in case of
 explicit template instantiation)

	PR c++/42608
	* varasm.c (declare_weak): Add weak attribute to decl if it
	doesn't have one already.
	(assemble_external): Only add decls to weak_decls if they also
	have weak attribute.

	* g++.dg/template/instantiate11.C: New test.

From-SVN: r155919
---
 gcc/ChangeLog                                 |  8 ++++++
 gcc/testsuite/ChangeLog                       |  5 ++++
 gcc/testsuite/g++.dg/template/instantiate11.C | 25 +++++++++++++++++++
 gcc/varasm.c                                  |  7 +++++-
 4 files changed, 44 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/template/instantiate11.C

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ce49f3683a6..29f71b12d14 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2010-01-14  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/42608
+	* varasm.c (declare_weak): Add weak attribute to decl if it
+	doesn't have one already.
+	(assemble_external): Only add decls to weak_decls if they also
+	have weak attribute.
+
 2010-01-14  Alexandre Oliva  <aoliva@redhat.com>
 
 	* var-tracking.c (var_reg_delete): Don't delete the association
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 7c89ccde3bd..5b284490686 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2010-01-14  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/42608
+	* g++.dg/template/instantiate11.C: New test.
+
 2010-01-14  Jason Merrill  <jason@redhat.com>
 
 	PR c++/42701
diff --git a/gcc/testsuite/g++.dg/template/instantiate11.C b/gcc/testsuite/g++.dg/template/instantiate11.C
new file mode 100644
index 00000000000..3598d5890bf
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/instantiate11.C
@@ -0,0 +1,25 @@
+// PR c++/42608
+// { dg-do compile }
+
+template <class U, class V>
+struct A;
+
+template <class V>
+struct A<int, V>
+{
+  void f ();
+};
+
+template struct A<int, int>;
+
+int
+main ()
+{
+  A<int, int> a;
+  a.f ();
+  return 0;
+}
+
+// Make sure we get undefined reference error if
+// A<int, int>::f () isn't instantiated elsewhere.
+// { dg-final { scan-assembler-not "weak\[\n\t\]*_ZN1AIiiE1fEv" } }
diff --git a/gcc/varasm.c b/gcc/varasm.c
index fab62198053..7ed59055745 100644
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -2337,13 +2337,15 @@ assemble_external (tree decl ATTRIBUTE_UNUSED)
   /* We want to output annotation for weak and external symbols at
      very last to check if they are references or not.  */
 
-  if (SUPPORTS_WEAK && DECL_WEAK (decl)
+  if (SUPPORTS_WEAK
+      && DECL_WEAK (decl)
       /* TREE_STATIC is a weird and abused creature which is not
 	 generally the right test for whether an entity has been
 	 locally emitted, inlined or otherwise not-really-extern, but
 	 for declarations that can be weak, it happens to be
 	 match.  */
       && !TREE_STATIC (decl)
+      && lookup_attribute ("weak", DECL_ATTRIBUTES (decl))
       && value_member (decl, weak_decls) == NULL_TREE)
     weak_decls = tree_cons (NULL, decl, weak_decls);
 
@@ -5227,6 +5229,9 @@ declare_weak (tree decl)
     warning (0, "weak declaration of %q+D not supported", decl);
 
   mark_weak (decl);
+  if (!lookup_attribute ("weak", DECL_ATTRIBUTES (decl)))
+    DECL_ATTRIBUTES (decl)
+      = tree_cons (get_identifier ("weak"), NULL, DECL_ATTRIBUTES (decl));
 }
 
 static void
-- 
2.30.2