* call.c (build_x_va_arg): Support passing non-POD through ....

	(convert_arg_to_ellipsis): Likewise.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@213921 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 30 insertions, 18 deletions

diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index 64cab453ae0..43bfe504d21 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -6570,8 +6570,8 @@ convert_arg_to_ellipsis (tree arg, tsubst_flags_t complain)
 	 with no corresponding parameter is conditionally-supported, with
 	 implementation-defined semantics.
 
-	 We used to just warn here and do a bitwise copy, but now
-	 cp_expr_size will abort if we try to do that.
+	 We support it as pass-by-invisible-reference, just like a normal
+	 value parameter.
 
 	 If the call appears in the context of a sizeof expression,
 	 it is not potentially-evaluated.  */
@@ -6579,10 +6579,12 @@ convert_arg_to_ellipsis (tree arg, tsubst_flags_t complain)
 	  && (type_has_nontrivial_copy_init (arg_type)
 	      || TYPE_HAS_NONTRIVIAL_DESTRUCTOR (arg_type)))
 	{
-	  if (complain & tf_error)
-	    error_at (loc, "cannot pass objects of non-trivially-copyable "
-		      "type %q#T through %<...%>", arg_type);
-	  return error_mark_node;
+	  if (complain & tf_warning)
+	    warning (OPT_Wconditionally_supported,
+		     "passing objects of non-trivially-copyable "
+		     "type %q#T through %<...%> is conditionally supported",
+		     arg_type);
+	  return cp_build_addr_expr (arg, complain);
 	}
     }
 
@@ -6595,7 +6597,11 @@ tree
 build_x_va_arg (source_location loc, tree expr, tree type)
 {
   if (processing_template_decl)
-    return build_min (VA_ARG_EXPR, type, expr);
+    {
+      tree r = build_min (VA_ARG_EXPR, type, expr);
+      SET_EXPR_LOCATION (r, loc);
+      return r;
+    }
 
   type = complete_type_or_else (type, NULL_TREE);
 
@@ -6604,18 +6610,24 @@ build_x_va_arg (source_location loc, tree expr, tree type)
 
   expr = mark_lvalue_use (expr);
 
+  if (TREE_CODE (type) == REFERENCE_TYPE)
+    {
+      error ("cannot receive reference type %qT through %<...%>", type);
+      return error_mark_node;
+    }
+
   if (type_has_nontrivial_copy_init (type)
-      || TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type)
-      || TREE_CODE (type) == REFERENCE_TYPE)
-    {
-      /* Remove reference types so we don't ICE later on.  */
-      tree type1 = non_reference (type);
-      /* conditionally-supported behavior [expr.call] 5.2.2/7.  */
-      error ("cannot receive objects of non-trivially-copyable type %q#T "
-	     "through %<...%>; ", type);
-      expr = convert (build_pointer_type (type1), null_node);
-      expr = cp_build_indirect_ref (expr, RO_NULL, tf_warning_or_error);
-      return expr;
+      || TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
+    {
+      /* conditionally-supported behavior [expr.call] 5.2.2/7.  Let's treat
+	 it as pass by invisible reference.  */
+      warning_at (loc, OPT_Wconditionally_supported,
+		 "receiving objects of non-trivially-copyable type %q#T "
+		 "through %<...%> is conditionally-supported", type);
+
+      tree ref = cp_build_reference_type (type, false);
+      expr = build_va_arg (loc, expr, ref);
+      return convert_from_reference (expr);
     }
 
   return build_va_arg (loc, expr, type);