* c-tree.h (c_build_va_arg): Adjust prototype.

	* c-parser.c (c_parser_postfix_expression): Adjust call to above.
	* c-typeck.c (c_build_va_arg): Rename LOC parameter to LOC2, add LOC1
	parameter, adjust throughout and issue an error if EXPR is a component
	with reverse storage order.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@231250 138bc75d-0d04-0410-961f-82ee72b054a4

6 files changed, 53 insertions, 6 deletions

diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index 213c407b75e..468ef9398be 100644
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,3 +1,11 @@
+2015-12-04  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* c-tree.h (c_build_va_arg): Adjust prototype.
+	* c-parser.c (c_parser_postfix_expression): Adjust call to above.
+	* c-typeck.c (c_build_va_arg): Rename LOC parameter to LOC2, add LOC1
+	parameter, adjust throughout and issue an error if EXPR is a component
+	with reverse storage order.
+
 2015-12-02  Jason Merrill  <jason@redhat.com>
 
 	* c-fold.c (c_disable_warnings, c_enable_warnings, c_fully_fold)
diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index ee0a30517af..c7d15f9fc38 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -7485,7 +7485,7 @@ c_parser_postfix_expression (c_parser *parser)
 	    else
 	      {
 		tree type_expr = NULL_TREE;
-		expr.value = c_build_va_arg (loc, e1.value,
+		expr.value = c_build_va_arg (start_loc, e1.value, loc,
 					     groktypename (t1, &type_expr, NULL));
 		if (type_expr)
 		  {
diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h
index 1c07065896a..00e72b115ca 100644
--- a/gcc/c/c-tree.h
+++ b/gcc/c/c-tree.h
@@ -661,7 +661,7 @@ extern tree c_finish_omp_task (location_t, tree, tree);
 extern void c_finish_omp_cancel (location_t, tree);
 extern void c_finish_omp_cancellation_point (location_t, tree);
 extern tree c_finish_omp_clauses (tree, bool, bool = false);
-extern tree c_build_va_arg (location_t, tree, tree);
+extern tree c_build_va_arg (location_t, tree, location_t, tree);
 extern tree c_finish_transaction (location_t, tree, int);
 extern bool c_tree_equal (tree, tree);
 extern tree c_build_function_call_vec (location_t, vec<location_t>, tree,
diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c
index 50709729c79..b691072caa9 100644
--- a/gcc/c/c-typeck.c
+++ b/gcc/c/c-typeck.c
@@ -13426,20 +13426,28 @@ c_build_qualified_type (tree type, int type_quals, tree orig_qual_type,
 /* Build a VA_ARG_EXPR for the C parser.  */
 
 tree
-c_build_va_arg (location_t loc, tree expr, tree type)
+c_build_va_arg (location_t loc1, tree expr, location_t loc2, tree type)
 {
   if (error_operand_p (type))
     return error_mark_node;
+  /* VA_ARG_EXPR cannot be used for a scalar va_list with reverse storage
+     order because it takes the address of the expression.  */
+  else if (handled_component_p (expr)
+	   && reverse_storage_order_for_component_p (expr))
+    {
+      error_at (loc1, "cannot use %<va_arg%> with reverse storage order");
+      return error_mark_node;
+    }
   else if (!COMPLETE_TYPE_P (type))
     {
-      error_at (loc, "second argument to %<va_arg%> is of incomplete "
+      error_at (loc2, "second argument to %<va_arg%> is of incomplete "
 		"type %qT", type);
       return error_mark_node;
     }
   else if (warn_cxx_compat && TREE_CODE (type) == ENUMERAL_TYPE)
-    warning_at (loc, OPT_Wc___compat,
+    warning_at (loc2, OPT_Wc___compat,
 		"C++ requires promoted type, not enum type, in %<va_arg%>");
-  return build_va_arg (loc, expr, type);
+  return build_va_arg (loc2, expr, type);
 }
 
 /* Return truthvalue of whether T1 is the same tree structure as T2.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2e93d1ade2b..ca604d26b4c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2015-12-04  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gcc.dg/sso-9.c: New test.
+
 2015-12-04  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/68655
diff --git a/gcc/testsuite/gcc.dg/sso-9.c b/gcc/testsuite/gcc.dg/sso-9.c
new file mode 100644
index 00000000000..6e767462e4d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/sso-9.c
@@ -0,0 +1,27 @@
+/* Test support of scalar_storage_order attribute */
+
+/* { dg-do compile } */
+
+#include <stdarg.h>
+
+int x;
+
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+struct __attribute__((scalar_storage_order("big-endian"))) Rec
+{
+  va_list v;
+};
+#else
+struct __attribute__((scalar_storage_order("little-endian"))) Rec
+{
+  va_list v;
+};
+#endif
+
+void foo (int i, ...)
+{
+  struct Rec a;
+  va_start (a.v, i);
+  a.v = a.v, x = va_arg (a.v, int); /* { dg-error "array type|reverse storage order" } */
+  va_end (a.v);
+}