re PR c++/51812 (Virtual public inheritance and thunks leads to "undefined…

re PR c++/51812 (Virtual public inheritance and thunks leads to "undefined reference" in header files.)

	PR c++/51812
	* cgraphunit.c (cgraph_decide_is_function_needed): Don't always
	output static aliases.

From-SVN: r183475

gcc/ChangeLog

+2012-01-24  Jason Merrill  <jason@redhat.com>
+
+	PR c++/51812
+	* cgraphunit.c (cgraph_decide_is_function_needed): Don't always
+	output static aliases.
+
 2012-01-24  Jakub Jelinek  <jakub@redhat.com>
 
 	PR driver/47249

gcc/cgraphunit.c

@@ -195,6 +195,7 @@ cgraph_decide_is_function_needed (struct cgraph_node *node, tree decl)
      to change the behavior here.  */
   if (((TREE_PUBLIC (decl)
 	|| (!optimize
+	    && !node->same_body_alias
 	    && !DECL_DISREGARD_INLINE_LIMITS (decl)
 	    && !DECL_DECLARED_INLINE_P (decl)
 	    && !(DECL_CONTEXT (decl)

gcc/testsuite/ChangeLog

+2012-01-24  Jason Merrill  <jason@redhat.com>
+
+	PR c++/51812
+	* g++.dg/inherit/covariant20.C: New.
+
 2012-01-24  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/51223

gcc/testsuite/g++.dg/inherit/covariant20.C

+// PR c++/51812
+// { dg-do link }
+
+class Object {
+  virtual Object* clone() const;
+};
+class DNA: virtual public Object {
+  virtual DNA* clone() const {return new DNA(*this);}
+};
+int main() { }