2014-08-08  Jason Merrill  <jason@redhat.com>

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

	* g++.dg/ext/varargs1.C: New test.
	* g++.old-deja/g++.other/vaarg3.C: Adjust dg-warning.
	* g++.old-deja/g++.brendan/crash63.C: Remove dg-warning.
	* g++.dg/warn/var-args1.C: Change dg-warning to dg-error.

--- gcc/cp/call.c
+++ gcc/cp/call.c
@@ -194,7 +194,6 @@ static conversion *direct_reference_binding (tree, conversion *);
 static bool promoted_arithmetic_type_p (tree);
 static conversion *conditional_conversion (tree, tree);
 static char *name_as_c_string (tree, tree, bool *);
-static tree call_builtin_trap (void);
 static tree prep_operand (tree);
 static void add_candidates (tree, tree, tree, bool, tree, tree,
 			    int, struct z_candidate **);
@@ -4909,18 +4908,6 @@ convert_like_real (conversion *convs, tree expr, tree fn, int argnum,
   return expr;
 }
 
-/* Build a call to __builtin_trap.  */
-
-static tree
-call_builtin_trap (void)
-{
-  tree fn = implicit_built_in_decls[BUILT_IN_TRAP];
-
-  gcc_assert (fn != NULL);
-  fn = build_call_n (fn, 0);
-  return fn;
-}
-
 /* ARG is being passed to a varargs function.  Perform any conversions
    required.  Return the converted value.  */
 
@@ -4958,11 +4945,9 @@ convert_arg_to_ellipsis (tree arg)
 	 there is no need to emit a warning, since the expression won't be
 	 evaluated. We keep the builtin_trap just as a safety check.  */
       if (!skip_evaluation)
-	warning (0, "cannot pass objects of non-POD type %q#T through %<...%>; "
-		 "call will abort at runtime", TREE_TYPE (arg));
-      arg = call_builtin_trap ();
-      arg = build2 (COMPOUND_EXPR, integer_type_node, arg,
-		    integer_zero_node);
+	warning (0, "cannot pass objects of non-POD type %q#T through %<...%>",
+		 TREE_TYPE (arg));
+      arg = cp_build_unary_op (ADDR_EXPR, arg, true, tf_warning_or_error);
     }
 
   return arg;
@@ -4983,19 +4968,20 @@ build_x_va_arg (tree expr, tree type)
 
   expr = mark_lvalue_use (expr);
 
-  if (TREE_ADDRESSABLE (type)
-      || TREE_CODE (type) == REFERENCE_TYPE)
+  if (TREE_CODE (type) == REFERENCE_TYPE)
     {
-      /* Remove reference types so we don't ICE later on.  */
-      tree type1 = non_reference (type);
+      error ("cannot receive reference type %qT through %<...%>", type);
+      return error_mark_node;
+    }
+
+  if (TREE_ADDRESSABLE (type))
+    {
+      tree ptr = build_pointer_type (type);
       /* Undefined behavior [expr.call] 5.2.2/7.  */
-      warning (0, "cannot receive objects of non-POD type %q#T through %<...%>; "
-	       "call will abort at runtime", type);
-      expr = convert (build_pointer_type (type1), null_node);
-      expr = build2 (COMPOUND_EXPR, TREE_TYPE (expr),
-		     call_builtin_trap (), expr);
-      expr = cp_build_indirect_ref (expr, NULL, tf_warning_or_error);
-      return expr;
+      warning (0, "cannot receive objects of non-POD type %q#T through %<...%>",
+	       type);
+      ptr = build_va_arg (expr, ptr);
+      return cp_build_indirect_ref (ptr, NULL, tf_warning_or_error);
     }
 
   return build_va_arg (expr, type);
--- gcc/testsuite/g++.dg/ext/varargs1.C
+++ gcc/testsuite/g++.dg/ext/varargs1.C
@@ -0,0 +1,31 @@
+#include <stdarg.h>
+extern "C" void abort();
+
+void *as[5];
+int i;
+
+struct A {
+  A() { as[i++] = this; }
+  A(const A& a) {
+    if (&a != as[i-1])
+      abort();
+    as[i++] = this;
+  }
+  ~A() {
+    if (this != as[--i])
+      abort();
+  }
+};
+
+void f(int i, ...) {
+  va_list ap;
+  va_start (ap, i);
+  A ar = va_arg (ap, A);	// { dg-warning "non-POD" }
+}
+
+int main()
+{
+  f(42,A());			// { dg-warning "non-POD" }
+  if (i != 0)
+    abort();
+}
--- gcc/testsuite/g++.dg/warn/var-args1.C
+++ gcc/testsuite/g++.dg/warn/var-args1.C
@@ -6,6 +6,6 @@ void foo(int, ...)
 {
     va_list va;
     int i;
-    i = va_arg(va, int&); /* { dg-warning "cannot receive objects" } */
+    i = va_arg(va, int&); /* { dg-error "cannot receive" } */
 }
 
--- gcc/testsuite/g++.old-deja/g++.brendan/crash63.C
+++ gcc/testsuite/g++.old-deja/g++.brendan/crash63.C
@@ -12,4 +12,4 @@ class UnitList
    UnitList (...);
    };
 
-UnitList unit_list (String("keV")); // { dg-warning "" } cannot pass non-pod
+UnitList unit_list (String("keV"));
--- gcc/testsuite/g++.old-deja/g++.other/vaarg3.C
+++ gcc/testsuite/g++.old-deja/g++.other/vaarg3.C
@@ -9,14 +9,14 @@
 #include <stdarg.h>
 
 struct X {int m;};
-struct Y : X {int m;};
+struct Y { Y(const Y&); };
 struct Z;   // { dg-error "forward decl" } 
 void fn1(va_list args)
 {
   int i = va_arg (args, int);
   Y x = va_arg (args, Y);         // { dg-warning "cannot receive" } 
   Y y = va_arg (args, struct Y);  // { dg-warning "cannot receive" } 
-  int &r = va_arg (args, int &);  // { dg-warning "cannot receive" } 
+  int &r = va_arg (args, int &);  // { dg-error "cannot receive" }
   
   Z z1 = va_arg (args, Z);        // { dg-error "incomplete" } 
   const Z &z2 = va_arg (args, Z);       // { dg-error "incomplete" } 
@@ -25,7 +25,8 @@ void fn1(va_list args)
   // { dg-message "should pass" "pass" { target *-*-* } 24 }
   // { dg-message "abort" "abort" { target *-*-* } 24 }
   va_arg (args, int []);  // { dg-error "array with unspecified bounds" } promote
-  va_arg (args, int ());  // { dg-warning "non-POD" } promote
+  va_arg (args, int ());  // { dg-warning "promote" } promote
+  // { dg-message "abort" "abort" { target *-*-* } 28 }
   va_arg (args, bool);    // { dg-warning "promote" "promote" } 
-  // { dg-message "abort" "abort" { target *-*-* } 29 }
+  // { dg-message "abort" "abort" { target *-*-* } 30 }
 }