re PR debug/49090 (provide a way to recognize defaulted template parameters)

	PR debug/49090
	* dwarf2out.c (gen_generic_params_dies): Indicate default arguments
	with DW_AT_default_value.

From-SVN: r196723

gcc/ChangeLog

+2013-03-16  Jason Merrill  <jason@redhat.com>
+
+	PR debug/49090
+	* dwarf2out.c (gen_generic_params_dies): Indicate default arguments
+	with DW_AT_default_value.
+
 2013-03-16  Jakub Jelinek  <jakub@redhat.com>
 
 	* BASE-VER: Set to 4.9.0.

gcc/dwarf2out.c

@@ -10238,6 +10238,7 @@ gen_generic_params_dies (tree t)
   tree parms, args;
   int parms_num, i;
   dw_die_ref die = NULL;
+  int non_default;
 
   if (!t || (TYPE_P (t) && !COMPLETE_TYPE_P (t)))
     return;
@@ -10257,9 +10258,14 @@ gen_generic_params_dies (tree t)
 
   parms_num = TREE_VEC_LENGTH (parms);
   args = lang_hooks.get_innermost_generic_args (t);
+  if (TREE_CHAIN (args) && TREE_CODE (TREE_CHAIN (args)) == INTEGER_CST)
+    non_default = int_cst_value (TREE_CHAIN (args));
+  else
+    non_default = TREE_VEC_LENGTH (args);
   for (i = 0; i < parms_num; i++)
     {
       tree parm, arg, arg_pack_elems;
+      dw_die_ref parm_die;
 
       parm = TREE_VEC_ELT (parms, i);
       arg = TREE_VEC_ELT (args, i);
@@ -10274,12 +10280,14 @@ gen_generic_params_dies (tree t)
 	     pack elements of ARG. Note that ARG would then be
 	     an argument pack.  */
 	  if (arg_pack_elems)
-	    template_parameter_pack_die (TREE_VALUE (parm),
-					 arg_pack_elems,
-					 die);
+	    parm_die = template_parameter_pack_die (TREE_VALUE (parm),
+						    arg_pack_elems,
+						    die);
 	  else
-	    generic_parameter_die (TREE_VALUE (parm), arg,
-				   true /* Emit DW_AT_name */, die);
+	    parm_die = generic_parameter_die (TREE_VALUE (parm), arg,
+					      true /* emit name */, die);
+	  if (i >= non_default)
+	    add_AT_flag (parm_die, DW_AT_default_value, 1);
 	}
     }
 }

gcc/langhooks.h

@@ -407,8 +407,10 @@ struct lang_hooks
 
   struct lang_hooks_for_lto lto;
 
-  /* Returns the generic parameters of an instantiation of
-     a generic type or decl, e.g. C++ template instantiation.  */
+  /* Returns a TREE_VEC of the generic parameters of an instantiation of
+     a generic type or decl, e.g. C++ template instantiation.  If
+     TREE_CHAIN of the return value is set, it is an INTEGER_CST
+     indicating how many of the elements are non-default.  */
   tree (*get_innermost_generic_parms) (const_tree);
 
   /* Returns the TREE_VEC of arguments of an instantiation