re PR c++/31165 (Error: symbol `an_empty_string' is already defined)

2007-03-14  Andrew Pinski  <andrew_pinski@playstation.sony.com>

        PR c++/31165
        * call.c  (convert_default_arg): Instead of copying the node,
        unshare it.
2007-03-14  Andrew Pinski  <andrew_pinski@playstation.sony.com>

        PR C++/31165
        * g++.dg/other/default7.C: New test.

From-SVN: r122941

gcc/cp/ChangeLog

+2007-03-14  Andrew Pinski  <andrew_pinski@playstation.sony.com>
+
+	PR c++/31165
+	* call.c  (convert_default_arg): Instead of copying the node,
+	unshare it.
+
 2007-03-15  Dirk Mueller  <dmueller@suse.de>
 
 	PR c++/30860

gcc/cp/call.c

@@ -4683,7 +4683,7 @@ convert_default_arg (tree type, tree arg, tree fn, int parmnum)
 	 VAR_DECL.  We can avoid the copy for constants, since they
 	 are never modified in place.  */
       if (!CONSTANT_CLASS_P (arg))
-	arg = copy_node (arg);
+	arg = unshare_expr (arg);
       arg = convert_for_initialization (0, type, arg, LOOKUP_NORMAL,
 					"default argument", fn, parmnum);
       arg = convert_for_arg_passing (type, arg);

gcc/testsuite/ChangeLog

+2007-03-14  Andrew Pinski  <andrew_pinski@playstation.sony.com>
+
+	PR C++/31165
+	* g++.dg/other/default7.C: New test.
+
 2007-03-15  Dirk Mueller  <dmueller@suse.de>
 
 	* g++.dg/warn/Wconversion2.C: New.

gcc/testsuite/g++.dg/other/default7.C

+/* { dg-do assemble } */
+/* { dg-options "-O1" }*/
+// This was PR C++/31165
+// We used to copy the whole decl when we just wantted to
+// unshare some expressions for the default argument.
+class string {
+  char *ptr;
+  int len;
+  int sz;
+};
+class cset { }  _cset_init;
+string an_empty_string;
+void f(string& = an_empty_string);
+void
+h (void )
+{
+f();
+}
+
+