re PR c++/59012 (alignas does not support parameter pack expansions)

	PR c++/59012
	* parser.c (cp_parser_std_attribute_list): Handle attribute expansion.
	(cp_parser_std_attribute_spec): Handle alignas pack expansion.
	* decl2.c (is_late_template_attribute): An attribute exp is dependent.
	* pt.c (make_pack_expansion): Allow TREE_LIST for attribute expansion.
	(apply_late_template_attributes): Handle attribute pack expansion.

From-SVN: r222902

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 3c32e6f77ddbb041e9c1a0dca40370d7cec0d3be..8427e9d2782a29d0023d5c1a1e59583a4ee4432a 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,12 @@
+2015-05-07  Jason Merrill  <jason@redhat.com>
+
+       PR c++/59012
+       * parser.c (cp_parser_std_attribute_list): Handle attribute expansion.
+       (cp_parser_std_attribute_spec): Handle alignas pack expansion.
+       * decl2.c (is_late_template_attribute): An attribute exp is dependent.
+       * pt.c (make_pack_expansion): Allow TREE_LIST for attribute expansion.
+       (apply_late_template_attributes): Handle attribute pack expansion.
+
 2015-05-07  Marek Polacek  <polacek@redhat.com>
 
        PR c/65179

diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index 0d478471925a0f4ec085376dc93234ca42eee88d..2276bd67acea877ab928202faf6a32fb1d209437 100644 (file)
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -1175,6 +1175,10 @@ is_late_template_attribute (tree attr, tree decl)
       && is_attribute_p ("omp declare simd", name))
     return true;
 
+  /* An attribute pack is clearly dependent.  */
+  if (args && PACK_EXPANSION_P (args))
+    return true;
+
   /* If any of the arguments are dependent expressions, we can't evaluate
      the attribute until instantiation time.  */
   for (arg = args; arg; arg = TREE_CHAIN (arg))

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 30a3fabbb986ef180e1bf453b530ea912b14198f..3d165da708fe36e0533560b686670dcbff233f68 100644 (file)
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -22486,6 +22486,13 @@ cp_parser_std_attribute_list (cp_parser *parser)
          attributes = attribute;
        }
       token = cp_lexer_peek_token (parser->lexer);
+      if (token->type == CPP_ELLIPSIS)
+       {
+         cp_lexer_consume_token (parser->lexer);
+         TREE_VALUE (attribute)
+           = make_pack_expansion (TREE_VALUE (attribute));
+         token = cp_lexer_peek_token (parser->lexer);
+       }
       if (token->type != CPP_COMMA)
        break;
       cp_lexer_consume_token (parser->lexer);
@@ -22564,20 +22571,27 @@ cp_parser_std_attribute_spec (cp_parser *parser)
            return alignas_expr;
        }
 
+      alignas_expr = cxx_alignas_expr (alignas_expr);
+      alignas_expr = build_tree_list (NULL_TREE, alignas_expr);
+
+      if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS))
+       {
+         cp_lexer_consume_token (parser->lexer);
+         alignas_expr = make_pack_expansion (alignas_expr);
+       }
+
       if (cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN) == NULL)
        {
          cp_parser_error (parser, "expected %<)%>");
          return error_mark_node;
        }
 
-      alignas_expr = cxx_alignas_expr (alignas_expr);
-
       /* Build the C++-11 representation of an 'aligned'
         attribute.  */
       attributes =
        build_tree_list (build_tree_list (get_identifier ("gnu"),
                                          get_identifier ("aligned")),
-                        build_tree_list (NULL_TREE, alignas_expr));
+                        alignas_expr);
     }
 
   return attributes;

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 8e0e789916b28de801bda1a5812ae1d9bc48c435..78714745452c079f46db03e11e6dbad382aabd60 100644 (file)
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -3338,9 +3338,9 @@ make_pack_expansion (tree arg)
   if (!arg || arg == error_mark_node)
     return arg;
 
-  if (TREE_CODE (arg) == TREE_LIST)
+  if (TREE_CODE (arg) == TREE_LIST && TREE_PURPOSE (arg))
     {
-      /* The only time we will see a TREE_LIST here is for a base
+      /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
          class initializer.  In this case, the TREE_PURPOSE will be a
          _TYPE node (representing the base class expansion we're
          initializing) and the TREE_VALUE will be a TREE_LIST
@@ -9012,6 +9012,21 @@ apply_late_template_attributes (tree *decl_p, tree attributes, int attr_flags,
                      = tree_cons (NULL_TREE, TREE_VALUE (TREE_VALUE (t)),
                                   chain);
                }
+             else if (TREE_VALUE (t) && PACK_EXPANSION_P (TREE_VALUE (t)))
+               {
+                 /* An attribute pack expansion.  */
+                 tree purp = TREE_PURPOSE (t);
+                 tree pack = (tsubst_pack_expansion
+                              (TREE_VALUE (t), args, complain, in_decl));
+                 int len = TREE_VEC_LENGTH (pack);
+                 for (int i = 0; i < len; ++i)
+                   {
+                     tree elt = TREE_VEC_ELT (pack, i);
+                     *q = build_tree_list (purp, elt);
+                     q = &TREE_CHAIN (*q);
+                   }
+                 continue;
+               }
              else
                TREE_VALUE (t)
                  = tsubst_expr (TREE_VALUE (t), args, complain, in_decl,

diff --git a/gcc/testsuite/g++.dg/cpp0x/alignas4.C b/gcc/testsuite/g++.dg/cpp0x/alignas4.C
new file mode 100644 (file)
index 0000000..871aaef
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/alignas4.C
@@ -0,0 +1,19 @@
+// PR c++/59012
+// { dg-do compile { target c++11 } }
+// { dg-final { scan-assembler "align 8" { target x86_64-*-*-gnu } } }
+
+template <class... T>
+struct A
+{
+  alignas(T...) char t;
+};
+
+A<int,double> a;
+
+template <class... T>
+struct A2
+{
+  [[gnu::aligned (alignof (T))...]] char t;
+};
+
+A2<int,double> a2;