PR c++/53528 C++11 attribute support

This patch implements the c++-11 generalized attributes, described in
the N2761 paper[1].

The idea is to modify the front-end to accept the new attribute syntax
(including alignas expressions) and to build an internal
representation similar to the one we already have for GNU attributes.

This lets us re-use our existing GNU attribute mechanisms to support
the generalized c++11 attributes.

The patch does change the existing internal representation to support
scoped attribute (aka attributes with namespaces), which is a concept
that doesn't exist in GNU attributes.  I have thus put all existing
GNU extension attributes into the "gnu" namespace.  For instance, in
C++-11, the "unused" attribute would be represented as
"[[gnu::unused]]".  Because there is no syntax for scoped attributes
in C, writting "__attribute__((unused))" unconditionnally refers to
the "unused" attribute in the "gnu" namespace.

Note that this patch follows a conservative understanding of the
specification by disallowing attributes appertaining to types, unless
they apply to a type definition.

Tested on x86_64-unknown-linux-gnu and powerpc64-unknown-linux-gnu.

[1]: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2761.pdf

gcc/
	* plugin.h (register_scoped_attributes): Declare new function.
	* tree.h (enu attribute_flags::ATTR_FLAG_CXX_11): New flag.
	(lookup_scoped_attribute_spec, cxx_11_attribute_p)
	(get_attribute_name, get_attribute_namespace): Declare new functions.
	(struct attribute_spec): Remove const qualifier from the members.
	* tree.c (comp_type_attributes, private_lookup_attribute)
	(lookup_ident_attribute, remove_attribute, merge_attribute)
	(attribute_hash_list, attribute_list_contained): Use
	get_attribute_name.
	* attribs.c (decl_attributes): Don't crash on error_mark_node.
	Forbid c++11 attributes appertaining to type-specifiers.
	(attribute_hash): Remove global variable.
	(attributes_table): New global variable.
	(find_attribute_namespace, register_scoped_attribute): New static
	functions.
	(register_scoped_attributes, lookup_scoped_attribute_spec)
	(cxx11_attribute_p, get_attribute_name, get_attribute_namespace):
	New public functions.
	(init_attributes): Register all the GNU attributes into the "gnu"
	namespace.
	(register_attribute): Use register_scoped_attribute to register
	the attribute into the "gnu" namespace.
	(lookup_attribute_spec): Use lookup_scoped_attribute_spec to
	lookup the attribute in the "gnu" namespace.
	(decl_attributes): Use new get_attribute_namespace and
	lookup_scoped_attribute_spec to consider attribute namespaces when
	looking up attributes.  When operating in c++-11 mode, pass flag
	ATTR_FLAG_CXX11 to the spec handler.

gcc/c-family/

	* c-common.h (bitfield_p, cxx_fundamental_alignment_p): Declare
	new functions.
	* c-common.c (check_cxx_fundamental_alignment_constraints): New
	static function.
	(handle_aligned_attribute): In choose strictest alignment
	among many.  Use new check_cxx_fundamental_alignment_constraints.
	(handle_transparent_union_attribute): In c++11 attribute syntax,
	don't look through typedefs.

gcc/cp/

	* cp-tree.h (enum cpp0x_warn_str::CPP0X_ATTRIBUTES): New member.
	(enum cp_decl_spec::ds_std_attribute): New enumerator.
	(struct cp_decl_specifier_seq::std_attributes): New field.
	(cxx_alignas_expr, warn_misplaced_attr_for_class_type): Declare
	new functions.
	(check_tag_decl): Take an extra parameter for explicit
	instantiations.
	* decl.c (warn_misplaced_attr_for_class_type): Extract from ...
	(check_tag_decl): ... here.  Add check for c++11 attributes being
	applied to an explicit instantiation.  Take an extra parameter for
	explicit instantiations.
	(grokdeclarator): Make sure a c++11 attribute after an array
	declarator appertains to the array, an attribute after a function
	declarator appertains to the function type, an attribute after a
	declarator-id appertains to the entity being declared, and an
	attribute after a pointer declarator appertains to the pointer.
	* decl2.c (is_late_template_attribute): Use get_attribute_name.
	* error.c (maybe_warn_cpp0x): Support
	CPP0X_GENERALIZED_ATTRIBUTES.
	* parser.c (cp_next_tokens_can_be_attribute_p)
	(cp_next_tokens_can_be_gnu_attribute_p)
	(cp_next_tokens_can_be_std_attribute_p)
	(cp_nth_tokens_can_be_attribute_p)
	(cp_nth_tokens_can_be_gnu_attribute_p)
	(cp_nth_tokens_can_be_std_attribute_p)
	(cp_parser_gnu_attribute_list, cp_parser_std_attribute)
	(cp_parser_std_attribute_spec, cp_parser_std_attribute_spec_seq)
	(cp_parser_attributes_opt, cp_parser_std_attribute_list): New
	static functions.
	(cp_parser_gnu_attributes_opt): Replace cp_parser_attributes_opt.
	(cp_parser_gnu_attribute_list): Replace cp_parser_attribute_list.
	(cp_parser_postfix_expression): Disallow "[[" tokens here.
	(cp_parser_label_for_labeled_statement): Use take an extra
	parameter for attributes.
	(cp_parser_block_declaration): Use
	cp_nth_tokens_can_be_std_attribute_p here.
	(cp_parser_decl_specifier_seq): Likewise.  Store C++11 attributes
	that appears in in decl specifiers in cp_decl_specifier_seq::std_attributes.
	declaration.  Emit proper warning about misplaced c++11 attributes
	for class type.
	(cp_parser_explicit_instantiation): Adjust call to check_tag_decl.
	(cp_parser_init_declarator):  Parsing attributes here is no more a
	GNU extension in c++-11.
	(cp_parser_type_specifier_seq): Use
	cp_next_tokens_can_be_attribute_p.
	(cp_parser_direct_declarator): Likewise.  Hang c++11 attributes
	following the declarator to its syntactic construct.  It'll later
	be applied to the proper appertaining entity by grokdeclarator.
	(cp_parser_ptr_operator): Likewise.
	(make_declarator): Initialize cp_declarator::std_attribute.
	(make_pointer_declarator, make_reference_declarator)
	(make_ptrmem_declarator, cp_parser_make_indirect_declarator): Take
	attributes that appertain to the pointer/reference in argument.
	(cp_parser_ptr_operator): Take an out parameter for c++11
	attributes.  Update comments.
	(cp_parser_new_declarator_opt)
	(cp_parser_conversion_declarator_opt): Adjust.
	(cp_parser_declarator): Likewise.  Handle C++11 attributes.
	Rename attributes to gnu_attribute for better legibility.
	(cp_parser_simple_declaration): Update comment.
	(cp_parser_class_specifier_1): Parse GNU attributes specifically
	(cp_parser_enum_specifier): Accept only gnu attributes after the
	specifier.
	(cp_parser_member_declaration): Don't clear attributes -- intended
	for the entity being declared -- too early because check_tag_decl
	needs them.
	(cp_parser_statement): Update comment.  Parse optional c++11
	attributes at the beginning of the relevant kind of statements and
	ignore them, for now, unless when calling
	cp_parser_label_for_labeled_statement.
	(cp_parser_label_for_labeled_statement): Take c++11 attributes
	in parameter.
	* semantics.c (potential_constant_expression_1): Likewise.
	* typeck.c (fundamental_alignment_p, cxx_alignas_expr): New public
	functions.

gcc/testsuite/

	* g++.dg/cpp0x/gen-attrs-1.C: New test.
	* g++.dg/cpp0x/gen-attrs-2.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-2-1.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-3.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-4.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-5.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-6.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-7.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-8.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-9.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-10.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-11.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-12.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-13.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-14.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-15.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-16.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-17.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-18.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-19.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-20.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-21.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-22.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-23.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-24.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-25.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-26.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-27.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-28.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-29.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-30.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-31.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-32.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-33.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-34.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-35.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-36.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-36-1.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-37.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-38.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-39.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-39-1.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-40.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-41.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-42.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-43.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-44.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-45.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-46.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-47.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-47-1.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-48.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-49.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-50.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-51.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-52.C: Likewise.
	* g++.dg/cpp0x/gen-attrs-53.C: Likewise.

From-SVN: r192199

gcc/ChangeLog

@@ -1,3 +1,35 @@
+2012-10-08  Dodji Seketeli  <dodji@redhat.com>
+
+	PR c++/53528 C++11 attribute support
+	* plugin.h (register_scoped_attributes): Declare new function.
+	* tree.h (enu attribute_flags::ATTR_FLAG_CXX_11): New flag.
+	(lookup_scoped_attribute_spec, cxx_11_attribute_p)
+	(get_attribute_name, get_attribute_namespace): Declare new functions.
+	(struct attribute_spec): Remove const qualifier from the members.
+	* tree.c (comp_type_attributes, private_lookup_attribute)
+	(lookup_ident_attribute, remove_attribute, merge_attribute)
+	(attribute_hash_list, attribute_list_contained): Use
+	get_attribute_name.
+	* attribs.c (decl_attributes): Don't crash on error_mark_node.
+	Forbid c++11 attributes appertaining to type-specifiers.
+	(attribute_hash): Remove global variable.
+	(attributes_table): New global variable.
+	(find_attribute_namespace, register_scoped_attribute): New static
+	functions.
+	(register_scoped_attributes, lookup_scoped_attribute_spec)
+	(cxx11_attribute_p, get_attribute_name, get_attribute_namespace):
+	New public functions.
+	(init_attributes): Register all the GNU attributes into the "gnu"
+	namespace.
+	(register_attribute): Use register_scoped_attribute to register
+	the attribute into the "gnu" namespace.
+	(lookup_attribute_spec): Use lookup_scoped_attribute_spec to
+	lookup the attribute in the "gnu" namespace.
+	(decl_attributes): Use new get_attribute_namespace and
+	lookup_scoped_attribute_spec to consider attribute namespaces when
+	looking up attributes.  When operating in c++-11 mode, pass flag
+	ATTR_FLAG_CXX11 to the spec handler.
+
 2012-10-08  Georg-Johann Lay  <avr@gjlay.de>
 
 	PR target/54815

gcc/attribs.c

@@ -38,9 +38,6 @@ along with GCC; see the file COPYING3.  If not see
    searched.  */
 static const struct attribute_spec *attribute_tables[4];
 
-/* Hashtable mapping names (represented as substrings) to attribute specs. */
-static htab_t attribute_hash;
-
 /* Substring representation.  */
 
 struct substring
@@ -49,6 +46,28 @@ struct substring
   int length;
 };
 
+DEF_VEC_O (attribute_spec);
+DEF_VEC_ALLOC_O (attribute_spec, heap);
+
+/* Scoped attribute name representation.  */
+
+struct scoped_attributes
+{
+  const char *ns;
+  VEC (attribute_spec, heap) *attributes;
+  htab_t attribute_hash;
+};
+
+DEF_VEC_O (scoped_attributes);
+DEF_VEC_ALLOC_O (scoped_attributes, heap);
+
+/* The table of scope attributes.  */
+static VEC(scoped_attributes, heap) *attributes_table;
+
+static scoped_attributes* find_attribute_namespace (const char*);
+static void register_scoped_attribute (const struct attribute_spec *,
+				       scoped_attributes *);
+
 static bool attributes_initialized = false;
 
 /* Default empty table of attributes.  */
@@ -102,6 +121,64 @@ eq_attr (const void *p, const void *q)
   return (!strncmp (spec->name, str->str, str->length) && !spec->name[str->length]);
 }
 
+/* Insert an array of attributes ATTRIBUTES into a namespace.  This
+   array must be NULL terminated.  NS is the name of attribute
+   namespace.  The function returns the namespace into which the
+   attributes have been registered.  */
+
+scoped_attributes*
+register_scoped_attributes (const struct attribute_spec * attributes,
+			    const char* ns)
+{
+  scoped_attributes *result = NULL;
+
+  /* See if we already have attributes in the namespace NS.  */
+  result = find_attribute_namespace (ns);
+
+  if (result == NULL)
+    {
+      /* We don't have any namespace NS yet.  Create one.  */
+      scoped_attributes sa;
+
+      if (attributes_table == NULL)
+	attributes_table = VEC_alloc (scoped_attributes, heap, 64);
+
+      memset (&sa, 0, sizeof (sa));
+      sa.ns = ns;
+      sa.attributes = VEC_alloc (attribute_spec, heap, 64);
+      result = VEC_safe_push (scoped_attributes, heap, attributes_table, sa);      
+    }
+
+  /* Really add the attributes to their namespace now.  */
+  for (unsigned i = 0; attributes[i].name != NULL; ++i)
+    {
+      VEC_safe_push (attribute_spec, heap,
+		     result->attributes, attributes[i]);
+      register_scoped_attribute (&attributes[i], result);
+    }
+
+  gcc_assert (result != NULL);
+
+  return result;
+}
+
+/* Return the namespace which name is NS, NULL if none exist.  */
+
+static scoped_attributes*
+find_attribute_namespace (const char* ns)
+{
+  unsigned ix;
+  scoped_attributes *iter;
+
+  FOR_EACH_VEC_ELT (scoped_attributes, attributes_table, ix, iter)
+    if (ns == iter->ns
+	|| (iter->ns != NULL
+	    && ns != NULL
+	    && !strcmp (iter->ns, ns)))
+      return iter;
+  return NULL;
+}
+
 /* Initialize attribute tables, and make some sanity checks
    if --enable-checking.  */
 
@@ -109,7 +186,6 @@ void
 init_attributes (void)
 {
   size_t i;
-  int k;
 
   if (attributes_initialized)
     return;
@@ -181,12 +257,10 @@ init_attributes (void)
     }
 #endif
 
-  attribute_hash = htab_create (200, hash_attr, eq_attr, NULL);
+  for (i = 0; i < ARRAY_SIZE (attribute_tables); ++i)
-  for (i = 0; i < ARRAY_SIZE (attribute_tables); i++)
+    /* Put all the GNU attributes into the "gnu" namespace.  */
-    for (k = 0; attribute_tables[i][k].name != NULL; k++)
+    register_scoped_attributes (attribute_tables[i], "gnu");
-      {
+
-        register_attribute (&attribute_tables[i][k]);
-      }
   invoke_plugin_callbacks (PLUGIN_ATTRIBUTES, NULL);
   attributes_initialized = true;
 }
@@ -195,10 +269,24 @@ init_attributes (void)
 
 void
 register_attribute (const struct attribute_spec *attr)
+{
+  register_scoped_attribute (attr, find_attribute_namespace ("gnu"));
+}
+
+/* Insert a single attribute ATTR into a namespace of attributes.  */
+
+static void
+register_scoped_attribute (const struct attribute_spec *attr,
+			   scoped_attributes *name_space)
 {
   struct substring str;
   void **slot;
 
+  gcc_assert (attr != NULL && name_space != NULL);
+
+  if (name_space->attribute_hash == NULL)
+   name_space->attribute_hash = htab_create (200, hash_attr, eq_attr, NULL);
+
   str.str = attr->name;
   str.length = strlen (str.str);
 
@@ -206,27 +294,45 @@ register_attribute (const struct attribute_spec *attr)
      in the form '__text__'.  */
   gcc_assert (str.length > 0 && str.str[0] != '_');
 
-  slot = htab_find_slot_with_hash (attribute_hash, &str,
+  slot = htab_find_slot_with_hash (name_space->attribute_hash, &str,
 				   substring_hash (str.str, str.length),
 				   INSERT);
   gcc_assert (!*slot || attr->name[0] == '*');
   *slot = (void *) CONST_CAST (struct attribute_spec *, attr);
 }
 
+/* Return the spec for the scoped attribute with namespace NS and
+   name NAME.   */
+
+const struct attribute_spec *
+lookup_scoped_attribute_spec (const_tree ns, const_tree name)
+{
+  struct substring attr;
+  scoped_attributes *attrs;
+
+  const char *ns_str = (ns != NULL_TREE) ? IDENTIFIER_POINTER (ns): NULL;
+
+  attrs = find_attribute_namespace (ns_str);
+
+  if (attrs == NULL)
+    return NULL;
+
+  attr.str = IDENTIFIER_POINTER (name);
+  attr.length = IDENTIFIER_LENGTH (name);
+  extract_attribute_substring (&attr);
+  return (const struct attribute_spec *)
+    htab_find_with_hash (attrs->attribute_hash, &attr,
+			 substring_hash (attr.str, attr.length));
+}
+
 /* Return the spec for the attribute named NAME.  */
 
 const struct attribute_spec *
 lookup_attribute_spec (const_tree name)
 {
-  struct substring attr;
+  return lookup_scoped_attribute_spec (get_identifier ("gnu"), name);
-
-  attr.str = IDENTIFIER_POINTER (name);
-  attr.length = IDENTIFIER_LENGTH (name);
-  extract_attribute_substring (&attr);
-  return (const struct attribute_spec *)
-    htab_find_with_hash (attribute_hash, &attr,
-			 substring_hash (attr.str, attr.length));
 }
+
 
 /* Process the attributes listed in ATTRIBUTES and install them in *NODE,
    which is either a DECL (including a TYPE_DECL) or a TYPE.  If a DECL,
@@ -243,7 +349,7 @@ decl_attributes (tree *node, tree attributes, int flags)
   tree a;
   tree returned_attrs = NULL_TREE;
 
-  if (TREE_TYPE (*node) == error_mark_node)
+  if (TREE_TYPE (*node) == error_mark_node || attributes == error_mark_node)
     return NULL_TREE;
 
   if (!attributes_initialized)
@@ -302,10 +408,12 @@ decl_attributes (tree *node, tree attributes, int flags)
 
   for (a = attributes; a; a = TREE_CHAIN (a))
     {
-      tree name = TREE_PURPOSE (a);
+      tree ns = get_attribute_namespace (a);
+      tree name = get_attribute_name (a);
       tree args = TREE_VALUE (a);
       tree *anode = node;
-      const struct attribute_spec *spec = lookup_attribute_spec (name);
+      const struct attribute_spec *spec =
+	lookup_scoped_attribute_spec (ns, name);
       bool no_add_attrs = 0;
       int fn_ptr_quals = 0;
       tree fn_ptr_tmp = NULL_TREE;
@@ -313,8 +421,15 @@ decl_attributes (tree *node, tree attributes, int flags)
       if (spec == NULL)
 	{
 	  if (!(flags & (int) ATTR_FLAG_BUILT_IN))
+	    {
+	      if (ns == NULL_TREE || !cxx11_attribute_p (a))
 		warning (OPT_Wattributes, "%qE attribute directive ignored",
 			 name);
+	      else
+		warning (OPT_Wattributes,
+			 "%<%E::%E%> scoped attribute directive ignored",
+			 ns, name);
+	    }
 	  continue;
 	}
       else if (list_length (args) < spec->min_length
@@ -327,6 +442,20 @@ decl_attributes (tree *node, tree attributes, int flags)
 	}
       gcc_assert (is_attribute_p (spec->name, name));
 
+      if (TYPE_P (*node)
+	  && cxx11_attribute_p (a)
+	  && !(flags & ATTR_FLAG_TYPE_IN_PLACE))
+	{
+	  /* This is a c++11 attribute that appertains to a
+	     type-specifier, outside of the definition of, a class
+	     type.  Ignore it.  */
+	  warning (OPT_Wattributes, "attribute ignored");
+	  inform (input_location,
+		  "an attribute that appertains to a type-specifier "
+		  "is ignored");
+	  continue;
+	}
+
       if (spec->decl_required && !DECL_P (*anode))
 	{
 	  if (flags & ((int) ATTR_FLAG_DECL_NEXT
@@ -406,9 +535,15 @@ decl_attributes (tree *node, tree attributes, int flags)
 	}
 
       if (spec->handler != NULL)
+	{
+	  int cxx11_flag =
+	    cxx11_attribute_p (a) ? ATTR_FLAG_CXX11 : 0;
+
 	  returned_attrs = chainon ((*spec->handler) (anode, name, args,
-						    flags, &no_add_attrs),
+						      flags|cxx11_flag,
+						      &no_add_attrs),
 				    returned_attrs);
+	}
 
       /* Layout the decl in case anything changed.  */
       if (spec->type_required && DECL_P (*node)
@@ -488,6 +623,56 @@ decl_attributes (tree *node, tree attributes, int flags)
   return returned_attrs;
 }
 
+/* Return TRUE iff ATTR has been parsed by the front-end as a C++-11
+   attribute.
+
+   When G++ parses a C++11 attribute, it is represented as
+   a TREE_LIST which TREE_PURPOSE is itself a TREE_LIST.  TREE_PURPOSE
+   (TREE_PURPOSE (ATTR)) is the namespace of the attribute, and the
+   TREE_VALUE (TREE_PURPOSE (ATTR)) is its non-qualified name.  Please
+   use get_attribute_namespace and get_attribute_name to retrieve the
+   namespace and name of the attribute, as these accessors work with
+   GNU attributes as well.  */
+
+bool
+cxx11_attribute_p (const_tree attr)
+{
+  if (attr == NULL_TREE
+      || TREE_CODE (attr) != TREE_LIST)
+    return false;
+
+  return (TREE_CODE (TREE_PURPOSE (attr)) == TREE_LIST);
+}
+
+/* Return the name of the attribute ATTR.  This accessor works on GNU
+   and C++11 (scoped) attributes.
+
+   Please read the comments of cxx11_attribute_p to understand the
+   format of attributes.  */
+
+tree
+get_attribute_name (const_tree attr)
+{
+  if (cxx11_attribute_p (attr))
+    return TREE_VALUE (TREE_PURPOSE (attr));
+  return TREE_PURPOSE (attr);
+}
+
+/* Return the namespace of the attribute ATTR.  This accessor works on
+   GNU and C++11 (scoped) attributes.  On GNU attributes,
+   it returns an identifier tree for the string "gnu".
+
+   Please read the comments of cxx11_attribute_p to understand the
+   format of attributes.  */
+
+tree
+get_attribute_namespace (const_tree attr)
+{
+  if (cxx11_attribute_p (attr))
+    return TREE_PURPOSE (TREE_PURPOSE (attr));
+  return get_identifier ("gnu");
+}
+
 /* Subroutine of set_method_tm_attributes.  Apply TM attribute ATTR
    to the method FNDECL.  */
 

gcc/c-family/ChangeLog

@@ -1,3 +1,15 @@
+2012-10-08  Dodji Seketeli  <dodji@redhat.com>
+
+	PR c++/53528 C++11 attribute support
+	* c-common.h (bitfield_p, cxx_fundamental_alignment_p): Declare
+	new functions.
+	* c-common.c (check_cxx_fundamental_alignment_constraints): New
+	static function.
+	(handle_aligned_attribute): In choose strictest alignment
+	among many.  Use new check_cxx_fundamental_alignment_constraints.
+	(handle_transparent_union_attribute): In c++11 attribute syntax,
+	don't look through typedefs.
+
 2012-10-04  Arnaud Charlet  <charlet@adacore.com>
 
 	* c-ada-spec.c (print_ada_declaration): Remove handling of TDF_RAW.

gcc/c-family/c-common.c

@@ -484,6 +484,7 @@ const struct c_common_resword c_common_reswords[] =
   { "__underlying_type", RID_UNDERLYING_TYPE, D_CXXONLY },
   { "__volatile",	RID_VOLATILE,	0 },
   { "__volatile__",	RID_VOLATILE,	0 },
+  { "alignas",		RID_ALIGNAS,	D_CXXONLY | D_CXX0X | D_CXXWARN },
   { "alignof",		RID_ALIGNOF,	D_CXXONLY | D_CXX0X | D_CXXWARN },
   { "asm",		RID_ASM,	D_ASM },
   { "auto",		RID_AUTO,	0 },
@@ -6665,7 +6666,9 @@ handle_transparent_union_attribute (tree *node, tree name,
 
   *no_add_attrs = true;
 
-  if (TREE_CODE (*node) == TYPE_DECL)
+
+  if (TREE_CODE (*node) == TYPE_DECL
+      && ! (flags & ATTR_FLAG_CXX11))
     node = &TREE_TYPE (*node);
   type = *node;
 
@@ -7137,6 +7140,89 @@ check_user_alignment (const_tree align, bool allow_zero)
   return i;
 }
 
+/* 
+   If in c++-11, check if the c++-11 alignment constraint with respect
+   to fundamental alignment (in [dcl.align]) are satisfied.  If not in
+   c++-11 mode, does nothing.
+
+   [dcl.align]2/ says:
+
+   [* if the constant expression evaluates to a fundamental alignment,
+   the alignment requirement of the declared entity shall be the
+   specified fundamental alignment.
+
+   * if the constant expression evaluates to an extended alignment
+   and the implementation supports that alignment in the context
+   of the declaration, the alignment of the declared entity shall
+   be that alignment
+
+   * if the constant expression evaluates to an extended alignment
+   and the implementation does not support that alignment in the
+   context of the declaration, the program is ill-formed].  */
+
+static bool
+check_cxx_fundamental_alignment_constraints (tree node,
+					     unsigned align_log,
+					     int flags)
+{
+  bool alignment_too_large_p = false;
+  unsigned requested_alignment = 1U << align_log;
+  unsigned max_align = 0;
+
+  if ((!(flags & ATTR_FLAG_CXX11) && !warn_cxx_compat)
+      || (node == NULL_TREE || node == error_mark_node))
+    return true;
+
+  if (cxx_fundamental_alignment_p (requested_alignment))
+    return true;
+
+  if (DECL_P (node))
+    {
+      if (TREE_STATIC (node))
+	{
+	  /* For file scope variables and static members, the target
+	     supports alignments that are at most
+	     MAX_OFILE_ALIGNMENT.  */
+	  if (requested_alignment > (max_align = MAX_OFILE_ALIGNMENT))
+	    alignment_too_large_p = true;
+	}
+      else
+	{
+#ifdef BIGGEST_FIELD_ALIGNMENT
+#define MAX_TARGET_FIELD_ALIGNMENT BIGGEST_FIELD_ALIGNMENT
+#else
+#define MAX_TARGET_FIELD_ALIGNMENT BIGGEST_ALIGNMENT
+#endif
+	  /* For non-static members, the target supports either
+	     alignments that at most either BIGGEST_FIELD_ALIGNMENT
+	     if it is defined or BIGGEST_ALIGNMENT.  */
+	  max_align = MAX_TARGET_FIELD_ALIGNMENT;
+	  if (TREE_CODE (node) == FIELD_DECL
+	      && requested_alignment > (max_align = MAX_TARGET_FIELD_ALIGNMENT))
+	    alignment_too_large_p = true;
+#undef MAX_TARGET_FIELD_ALIGNMENT
+	  /* For stack variables, the target supports at most
+	     MAX_STACK_ALIGNMENT.  */
+	  else if (decl_function_context (node) != NULL
+		   && requested_alignment > (max_align = MAX_STACK_ALIGNMENT))
+	    alignment_too_large_p = true;
+	}
+    }
+  else if (TYPE_P (node))
+    {
+      /* Let's be liberal for types.  */
+      if (requested_alignment > (max_align = BIGGEST_ALIGNMENT))
+	alignment_too_large_p = true;
+    }
+
+  if (alignment_too_large_p)
+    pedwarn (input_location, OPT_Wattributes,
+	     "requested alignment %d is larger than %d",
+	     requested_alignment, max_align);
+
+  return !alignment_too_large_p;
+}
+
 /* Handle a "aligned" attribute; arguments as in
    struct attribute_spec.handler.  */
 
@@ -7160,7 +7246,8 @@ handle_aligned_attribute (tree *node, tree ARG_UNUSED (name), tree args,
   else if (TYPE_P (*node))
     type = node, is_type = 1;
 
-  if ((i = check_user_alignment (align_expr, false)) == -1)
+  if ((i = check_user_alignment (align_expr, false)) == -1
+      || !check_cxx_fundamental_alignment_constraints (*node, i, flags))
     *no_add_attrs = true;
   else if (is_type)
     {
@@ -7190,6 +7277,17 @@ handle_aligned_attribute (tree *node, tree ARG_UNUSED (name), tree args,
       error ("alignment may not be specified for %q+D", decl);
       *no_add_attrs = true;
     }
+  else if (DECL_USER_ALIGN (decl)
+	   && DECL_ALIGN (decl) > (1U << i) * BITS_PER_UNIT)
+    /* C++-11 [dcl.align/4]:
+
+           When multiple alignment-specifiers are specified for an
+	   entity, the alignment requirement shall be set to the
+	   strictest specified alignment.
+
+      This formally comes from the c++11 specification but we are
+      doing it for the GNU attribute syntax as well.  */
+    *no_add_attrs = true;
   else if (TREE_CODE (decl) == FUNCTION_DECL
 	   && DECL_ALIGN (decl) > (1U << i) * BITS_PER_UNIT)
     {
@@ -11154,4 +11252,22 @@ convert_vector_to_pointer_for_subscript (location_t loc,
     }
 }
 
+/* Return true iff ALIGN is an integral constant that is a fundamental
+   alignment, as defined by [basic.align] in the c++-11
+   specifications.
+
+   That is:
+
+       [A fundamental alignment is represented by an alignment less than or
+        equal to the greatest alignment supported by the implementation
+        in all contexts, which is equal to
+        alignof(max_align_t)].  */
+
+bool
+cxx_fundamental_alignment_p  (unsigned align)
+{
+  return (align <=  MAX (TYPE_ALIGN (long_long_integer_type_node),
+			 TYPE_ALIGN (long_double_type_node)));
+}
+
 #include "gt-c-family-c-common.h"

gcc/c-family/c-common.h

@@ -789,6 +789,7 @@ extern bool keyword_begins_type_specifier (enum rid);
 extern bool keyword_is_storage_class_specifier (enum rid);
 extern bool keyword_is_type_qualifier (enum rid);
 extern bool keyword_is_decl_specifier (enum rid);
+extern bool cxx_fundamental_alignment_p (unsigned);
 
 #define c_sizeof(LOC, T)  c_sizeof_or_alignof_type (LOC, T, true, 1)
 #define c_alignof(LOC, T) c_sizeof_or_alignof_type (LOC, T, false, 1)

gcc/cp/ChangeLog

@@ -1,3 +1,82 @@
+2012-10-08  Dodji Seketeli  <dodji@redhat.com>
+
+	PR c++/53528 C++11 attribute support
+	* cp-tree.h (enum cpp0x_warn_str::CPP0X_ATTRIBUTES): New member.
+	(enum cp_decl_spec::ds_std_attribute): New enumerator.
+	(struct cp_decl_specifier_seq::std_attributes): New field.
+	(cxx_alignas_expr, warn_misplaced_attr_for_class_type): Declare
+	new functions.
+	(check_tag_decl): Take an extra parameter for explicit
+	instantiations.
+	* decl.c (warn_misplaced_attr_for_class_type): Extract from ...
+	(check_tag_decl): ... here.  Add check for c++11 attributes being
+	applied to an explicit instantiation.  Take an extra parameter for
+	explicit instantiations.
+	(grokdeclarator): Make sure a c++11 attribute after an array
+	declarator appertains to the array, an attribute after a function
+	declarator appertains to the function type, an attribute after a
+	declarator-id appertains to the entity being declared, and an
+	attribute after a pointer declarator appertain to the pointer.
+	* decl2.c (is_late_template_attribute): Use get_attribute_name.
+	* error.c (maybe_warn_cpp0x): Support
+	CPP0X_GENERALIZED_ATTRIBUTES.
+	* parser.c (cp_next_tokens_can_be_attribute_p)
+	(cp_next_tokens_can_be_gnu_attribute_p)
+	(cp_next_tokens_can_be_std_attribute_p)
+	(cp_nth_tokens_can_be_attribute_p)
+	(cp_nth_tokens_can_be_gnu_attribute_p)
+	(cp_nth_tokens_can_be_std_attribute_p)
+	(cp_parser_gnu_attribute_list, cp_parser_std_attribute)
+	(cp_parser_std_attribute_spec, cp_parser_std_attribute_spec_seq)
+	(cp_parser_attributes_opt, cp_parser_std_attribute_list): New
+	static functions.
+	(cp_parser_gnu_attributes_opt): Replace cp_parser_attributes_opt.
+	(cp_parser_gnu_attribute_list): Replace cp_parser_attribute_list.
+	(cp_parser_postfix_expression): Disallow "[[" tokens here.
+	(cp_parser_label_for_labeled_statement): Use take an extra
+	parameter for attributes.
+	(cp_parser_block_declaration): Use
+	cp_nth_tokens_can_be_std_attribute_p here.
+	(cp_parser_decl_specifier_seq): Likewise.  Store C++11 attributes
+	that appears in in decl specifiers in cp_decl_specifier_seq::std_attributes.
+	declaration.  Emit proper warning about misplaced c++11 attributes
+	for class type.
+	(cp_parser_explicit_instantiation): Adjust call to check_tag_decl.
+	(cp_parser_init_declarator):  Parsing attributes here is no more a
+	GNU extension in c++-11.
+	(cp_parser_type_specifier_seq): Use
+	cp_next_tokens_can_be_attribute_p.
+	(cp_parser_direct_declarator): Likewise.  Hang c++11 attributes
+	following the declarator to its syntactic construct.  It'll later
+	be applied to the proper appertaining entity by grokdeclarator.
+	(cp_parser_ptr_operator): Likewise.
+	(make_declarator): Initialize cp_declarator::std_attribute.
+	(make_pointer_declarator, make_reference_declarator)
+	(make_ptrmem_declarator, cp_parser_make_indirect_declarator): Take
+	attributes that appertain to the pointer/reference in argument.
+	(cp_parser_ptr_operator): Take an out parameter for c++11
+	attributes.  Update comments.
+	(cp_parser_new_declarator_opt)
+	(cp_parser_conversion_declarator_opt): Adjust.
+	(cp_parser_declarator): Likewise.  Handle C++11 attributes.
+	Rename attributes to gnu_attribute for better legibility.
+	(cp_parser_simple_declaration): Update comment.
+	(cp_parser_class_specifier_1): Parse GNU attributes specifically
+	(cp_parser_enum_specifier): Accept only gnu attributes after the
+	specifier.
+	(cp_parser_member_declaration): Don't clear attributes -- intended
+	for the entity being declared -- too early because check_tag_decl
+	needs them.
+	(cp_parser_statement): Update comment.  Parse optional c++11
+	attributes at the beginning of the relevant kind of statements and
+	ignore them, for now, unless when calling
+	cp_parser_label_for_labeled_statement.
+	(cp_parser_label_for_labeled_statement): Take c++11 attributes
+	in parameter.
+	* semantics.c (potential_constant_expression_1): Likewise.
+	* typeck.c (fundamental_alignment_p, cxx_alignas_expr): New public
+	functions.
+
 2012-10-07  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* pt.c (fold_non_dependent_expr_sfinae): Remove static specifier.

gcc/cp/cp-tree.h

@@ -418,7 +418,9 @@ typedef enum cpp0x_warn_str
   /* user defined literals */
   CPP0X_USER_DEFINED_LITERALS,
   /* delegating constructors */
-  CPP0X_DELEGATING_CTORS
+  CPP0X_DELEGATING_CTORS,
+  /* C++11 attributes */
+  CPP0X_ATTRIBUTES
 } cpp0x_warn_str;
   
 /* The various kinds of operation used by composite_pointer_type. */
@@ -4684,6 +4686,7 @@ typedef enum cp_decl_spec {
   ds_type_spec,
   ds_redefined_builtin_type_spec,
   ds_attribute,
+  ds_std_attribute,
   ds_storage_class,
   ds_long_long,
   ds_last /* This enumerator must always be the last one.  */
@@ -4702,6 +4705,8 @@ typedef struct cp_decl_specifier_seq {
   tree type;
   /* The attributes, if any, provided with the specifier sequence.  */
   tree attributes;
+  /* The c++11 attributes that follows the type specifier.  */
+  tree std_attributes;
   /* If non-NULL, a built-in type that the user attempted to redefine
      to some other type.  */
   tree redefined_builtin_type;
@@ -4770,8 +4775,14 @@ struct cp_declarator {
      to indicate this is a parameter pack.  */
   BOOL_BITFIELD parameter_pack_p : 1;
   location_t id_loc; /* Currently only set for cdk_id and cdk_function. */
-  /* Attributes that apply to this declarator.  */
+  /* GNU Attributes that apply to this declarator.  If the declarator
+     is a pointer or a reference, these attribute apply to the type
+     pointed to.  */
   tree attributes;
+  /* Standard C++11 attributes that apply to this declarator.  If the
+     declarator is a pointer or a reference, these attributes apply
+     to the pointer, rather than to the type pointed to.  */
+  tree std_attributes;
   /* For all but cdk_id and cdk_error, the contained declarator.  For
      cdk_id and cdk_error, guaranteed to be NULL.  */
   cp_declarator *declarator;
@@ -5068,7 +5079,9 @@ extern tree build_cp_library_fn_ptr		(const char *, tree);
 extern tree push_library_fn			(tree, tree, tree);
 extern tree push_void_library_fn		(tree, tree);
 extern tree push_throw_library_fn		(tree, tree);
-extern tree check_tag_decl			(cp_decl_specifier_seq *);
+extern void warn_misplaced_attr_for_class_type  (source_location location,
+						 tree class_type);
+extern tree check_tag_decl			(cp_decl_specifier_seq *, bool);
 extern tree shadow_tag				(cp_decl_specifier_seq *);
 extern tree groktypename			(cp_decl_specifier_seq *, const cp_declarator *, bool);
 extern tree start_decl				(const cp_declarator *, cp_decl_specifier_seq *, int, tree, tree, tree *);
@@ -5829,6 +5842,7 @@ extern int comp_cv_qualification		(const_tree, const_tree);
 extern int comp_cv_qual_signature		(tree, tree);
 extern tree cxx_sizeof_or_alignof_expr		(tree, enum tree_code, bool);
 extern tree cxx_sizeof_or_alignof_type		(tree, enum tree_code, bool);
+extern tree cxx_alignas_expr                    (tree);
 extern tree cxx_sizeof_nowarn                   (tree);
 extern tree is_bitfield_expr_with_lowered_type  (const_tree);
 extern tree unlowered_expr_type                 (const_tree);

gcc/cp/decl.c

@@ -4132,13 +4132,32 @@ fixup_anonymous_aggr (tree t)
     }
 }
 
+/* Warn for an attribute located at LOCATION that appertains to the
+   class type CLASS_TYPE that has not been properly placed after its
+   class-key, in it class-specifier.  */
+
+void
+warn_misplaced_attr_for_class_type (source_location location,
+				    tree class_type)
+{
+  gcc_assert (TAGGED_TYPE_P (class_type));
+
+  warning_at (location, OPT_Wattributes,
+	      "attribute ignored in declaration "
+	      "of %q#T", class_type);
+  inform (location,
+	  "attribute for %q#T must follow the %qs keyword",
+	  class_type, class_key_or_enum_as_string (class_type));
+}
+
 /* Make sure that a declaration with no declarator is well-formed, i.e.
    just declares a tagged type or anonymous union.
 
    Returns the type declared; or NULL_TREE if none.  */
 
 tree
-check_tag_decl (cp_decl_specifier_seq *declspecs)
+check_tag_decl (cp_decl_specifier_seq *declspecs,
+		bool explicit_type_instantiation_p)
 {
   int saw_friend = decl_spec_seq_has_spec_p (declspecs, ds_friend);
   int saw_typedef = decl_spec_seq_has_spec_p (declspecs, ds_typedef);
@@ -4247,10 +4266,22 @@ check_tag_decl (cp_decl_specifier_seq *declspecs)
 	/* For a template class (an explicit instantiation), use the
 	   current location.  */
 	loc = input_location;
-      warning_at (loc, OPT_Wattributes, "attribute ignored in declaration "
+
-		  "of %q#T", declared_type);
+      if (explicit_type_instantiation_p)
-      inform (loc, "attribute for %q#T must follow the %qs keyword",
+	/* [dcl.attr.grammar]/4:
-	      declared_type, class_key_or_enum_as_string (declared_type));
+
+	       No attribute-specifier-seq shall appertain to an explicit
+	       instantiation.  */
+	{
+	  warning_at (loc, OPT_Wattributes,
+		      "attribute ignored in explicit instantiation %q#T",
+		      declared_type);
+	  inform (loc,
+		  "no attribute can be applied to "
+		  "an explicit instantiation");
+	}
+      else
+	warn_misplaced_attr_for_class_type (loc, declared_type);
     }
 
   return declared_type;
@@ -4272,7 +4303,8 @@ check_tag_decl (cp_decl_specifier_seq *declspecs)
 tree
 shadow_tag (cp_decl_specifier_seq *declspecs)
 {
-  tree t = check_tag_decl (declspecs);
+  tree t = check_tag_decl (declspecs,
+			   /*explicit_type_instantiation_p=*/false);
 
   if (!t)
     return NULL_TREE;
@@ -9178,6 +9210,15 @@ grokdeclarator (const cp_declarator *declarator,
 	}
     }
 
+  if (declspecs->std_attributes)
+    {
+      /* Apply the c++11 attributes to the type preceding them.  */
+      source_location saved_loc = input_location;
+      input_location = declspecs->locations[ds_std_attribute];
+      decl_attributes (&type, declspecs->std_attributes, 0);
+      input_location = saved_loc;
+    }
+
   /* Determine the type of the entity declared by recurring on the
      declarator.  */
   for (; declarator; declarator = declarator->declarator)
@@ -9215,6 +9256,13 @@ grokdeclarator (const cp_declarator *declarator,
 	case cdk_array:
 	  type = create_array_type_for_decl (dname, type,
 					     declarator->u.array.bounds);
+	  if (declarator->std_attributes)
+	    /* [dcl.array]/1:
+
+	       The optional attribute-specifier-seq appertains to the
+	       array.  */
+	    returned_attrs = chainon (returned_attrs,
+				      declarator->std_attributes);
 	  break;
 
 	case cdk_function:
@@ -9411,6 +9459,13 @@ grokdeclarator (const cp_declarator *declarator,
 	      }
 
 	    type = build_function_type (type, arg_types);
+	    if (declarator->std_attributes)
+	      /* [dcl.fct]/2:
+
+		 The optional attribute-specifier-seq appertains to
+		 the function type.  */
+	      decl_attributes (&type, declarator->std_attributes,
+			       0);
 	  }
 	  break;
 
@@ -9573,6 +9628,17 @@ grokdeclarator (const cp_declarator *declarator,
 					   declarator->u.pointer.qualifiers);
 	      type_quals = cp_type_quals (type);
 	    }
+
+	  /* Apply C++11 attributes to the pointer, and not to the
+	     type pointed to.  This is unlike what is done for GNU
+	     attributes above.  It is to comply with [dcl.ptr]/1:
+
+		 [the optional attribute-specifier-seq (7.6.1) appertains
+		  to the pointer and not to the object pointed to].  */
+	  if (declarator->std_attributes)
+	    decl_attributes (&type, declarator->std_attributes,
+			     0);
+
 	  ctype = NULL_TREE;
 	  break;
 
@@ -9698,6 +9764,13 @@ grokdeclarator (const cp_declarator *declarator,
 	attrlist = &returned_attrs;
     }
 
+  if (declarator
+      && declarator->kind == cdk_id
+      && declarator->std_attributes)
+    /* [dcl.meaning]/1: The optional attribute-specifier-seq following
+       a declarator-id appertains to the entity that is declared.  */
+    *attrlist = chainon (*attrlist, declarator->std_attributes);
+
   /* Handle parameter packs. */
   if (parameter_pack_p)
     {

gcc/cp/decl2.c

@@ -1091,7 +1091,7 @@ grokbitfield (const cp_declarator *declarator,
 static bool
 is_late_template_attribute (tree attr, tree decl)
 {
-  tree name = TREE_PURPOSE (attr);
+  tree name = get_attribute_name (attr);
   tree args = TREE_VALUE (attr);
   const struct attribute_spec *spec = lookup_attribute_spec (name);
   tree arg;

gcc/cp/error.c

@@ -3374,6 +3374,11 @@ maybe_warn_cpp0x (cpp0x_warn_str str)
 		 "delegating constructors "
 		 "only available with -std=c++11 or -std=gnu++11");
         break;
+      case CPP0X_ATTRIBUTES:
+	pedwarn (input_location, 0,
+		 "c++11 attributes "
+		 "only available with -std=c++11 or -std=gnu++11");
+	break;
       default:
 	gcc_unreachable ();
       }

gcc/cp/typeck.c

@@ -1701,6 +1701,56 @@ cxx_sizeof_or_alignof_expr (tree e, enum tree_code op, bool complain)
   else
     return cxx_alignof_expr (e, complain? tf_warning_or_error : tf_none);
 }
+
+/*  Build a representation of an expression 'alignas(E).'  Return the
+    folded integer value of E if it is an integral constant expression
+    that resolves to a valid alignment.  If E depends on a template
+    parameter, return a syntactic representation tree of kind
+    ALIGNOF_EXPR.  Otherwise, return an error_mark_node if the
+    expression is ill formed, or NULL_TREE if E is NULL_TREE.  */
+
+tree
+cxx_alignas_expr (tree e)
+{
+  if (e == NULL_TREE || e == error_mark_node
+      || (!TYPE_P (e) && !require_potential_rvalue_constant_expression (e)))
+    return e;
+  
+  if (TYPE_P (e))
+    /* [dcl.align]/3:
+       
+	   When the alignment-specifier is of the form
+	   alignas(type-id ), it shall have the same effect as
+	   alignas( alignof(type-id )).  */
+
+    return cxx_sizeof_or_alignof_type (e, ALIGNOF_EXPR, false);
+  
+
+  /* If we reach this point, it means the alignas expression if of
+     the form "alignas(assignment-expression)", so we should follow
+     what is stated by [dcl.align]/2.  */
+
+  e = mark_rvalue_use (e);
+
+  /* [dcl.align]/2 says:
+
+         the assignment-expression shall be an integral constant
+	 expression.  */
+  
+  e = fold_non_dependent_expr (e);
+  if (value_dependent_expression_p (e))
+    /* Leave value-dependent expression alone for now. */;
+  else
+    e = cxx_constant_value (e);
+
+  if (e == NULL_TREE
+      || e == error_mark_node
+      || TREE_CODE (e) != INTEGER_CST)
+    return error_mark_node;
+
+  return e;
+}
+
 
 /* EXPR is being used in a context that is not a function call.
    Enforce:

gcc/plugin.h

@@ -23,6 +23,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "gcc-plugin.h"
 
 struct attribute_spec;
+struct scoped_attributes;
 
 extern void add_new_plugin (const char *);
 extern void parse_plugin_arg_opt (const char *);
@@ -64,5 +65,7 @@ invoke_plugin_callbacks (int event ATTRIBUTE_UNUSED,
 /* In attribs.c.  */
 
 extern void register_attribute (const struct attribute_spec *attr);
+extern struct scoped_attributes* register_scoped_attributes (const struct attribute_spec *,
+							     const char *);
 
 #endif /* PLUGIN_H */

gcc/testsuite/ChangeLog

@@ -1,3 +1,64 @@
+2012-10-08  Dodji Seketeli  <dodji@redhat.com>
+
+	PR c++/53528 C++11 attribute support
+	* g++.dg/cpp0x/gen-attrs-1.C: New test.
+	* g++.dg/cpp0x/gen-attrs-2.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-2-1.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-3.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-4.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-5.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-6.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-7.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-8.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-9.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-10.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-11.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-12.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-13.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-14.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-15.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-16.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-17.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-18.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-19.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-20.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-21.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-22.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-23.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-24.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-25.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-26.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-27.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-28.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-29.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-30.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-31.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-32.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-33.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-34.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-35.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-36.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-36-1.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-37.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-38.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-39.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-39-1.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-40.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-41.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-42.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-43.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-44.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-45.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-46.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-47.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-47-1.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-48.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-49.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-50.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-51.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-52.C: Likewise.
+	* g++.dg/cpp0x/gen-attrs-53.C: Likewise.
+
 2012-10-08  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gcc.dg/tree-ssa/slsr-30.c: Use correct cleanup directive.

gcc/testsuite/g++.dg/cpp0x/gen-attrs-1.C

@@ -0,0 +1,3 @@
+// { dg-do compile { target c++11 } }
+
+int **** [[gnu::format(printf, 1, 2)]] foo(const char *, ...); // { dg-warning "ignored" }

gcc/testsuite/g++.dg/cpp0x/gen-attrs-10.C

@@ -0,0 +1,9 @@
+// PR c++/12795
+// { dg-do compile { target c++11 } }
+// { dg-require-alias "" }
+
+void foo()
+{
+  extern void bar [[gnu::__alias__ ("BAR")]] (); // { dg-warning "ignored" }
+  bar ();
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-11.C

@@ -0,0 +1,17 @@
+// { dg-do compile { target c++11 } }
+// PR c++/13791
+
+template <typename T> struct O {
+  struct [[gnu::packed]] I {
+    int i;
+    char c;
+  };
+
+  I* foo();
+};
+
+template <typename T>
+typename O<T>::I*
+O<T>::foo() { return 0; }
+
+template class O<int>;

gcc/testsuite/g++.dg/cpp0x/gen-attrs-12.C

@@ -0,0 +1,17 @@
+// { dg-do compile { target c++11 } }
+// PR c++/13791
+
+template <typename T> struct O {
+  struct [[gnu::packed]] I {
+    int i;
+    char c;
+  };
+
+  I* foo();
+};
+
+template <typename T>
+typename O<T>::I*
+O<T>::foo() { return 0; }
+
+template class O<int>;

gcc/testsuite/g++.dg/cpp0x/gen-attrs-13.C

@@ -0,0 +1,5 @@
+// { dg-do compile { target c++11 } }
+// PR c++/13854
+
+extern char *rindex [[gnu::__pure__]] (__const char *__s, int __c) throw ();
+extern char *rindex [[gnu::__pure__]] (__const char *__s, int __c) throw ();

gcc/testsuite/g++.dg/cpp0x/gen-attrs-14.C

@@ -0,0 +1,14 @@
+// { dg-do compile { target c++11 } }
+// PR c++/13170
+// The bogus attribute is ignored, but was in TYPE_ATTRIBUTES during
+// parsing of the class, causing some variants to have it and some not.
+
+struct [[gnu::bogus]] A	// { dg-warning "ignored" "" }
+{
+    virtual ~A();
+    void foo(const A&);
+    void bar(const A&);
+};
+
+void A::foo(const A&)   {}
+void A::bar(const A& a) { foo(a); }

gcc/testsuite/g++.dg/cpp0x/gen-attrs-15.C

@@ -0,0 +1,9 @@
+// { dg-do compile { target c++11 } }
+// PR c++/15317
+
+struct A
+{
+  A(char);
+};
+A::A([[gnu::unused]] char i2)
+{}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-16.C

@@ -0,0 +1,8 @@
+// { dg-do compile { target c++11 } }
+// Origin: <rguenth at tat dot physik dot uni-tuebingen dot de>
+// PR c++/10479: use of non dependent expressions in attributes in templates
+
+template <int i>
+struct foo2 {
+  float bar [[gnu::aligned(alignof(double))]];
+};

gcc/testsuite/g++.dg/cpp0x/gen-attrs-17.2.C

@@ -0,0 +1,19 @@
+// { dg-do compile { target c++11 } }
+// Origin: Benjamin Kosnik <bkoz at gcc dot gnu dot org>
+// PR c++/17743: Attributes applied to typedefs.
+
+struct A {
+  typedef char layout_type[sizeof(double)]
+  [[gnu::aligned(alignof(double)]]); // { dg-error "expected" }
+  layout_type data;
+};
+
+struct B {
+  typedef char layout_type[sizeof(double)];
+  layout_type data  [[gnu::aligned(alignof(double))]];
+};
+
+template<bool> struct StaticAssert;
+template<> struct StaticAssert<true> {};
+
+StaticAssert<alignof(A) == alignof(B)> a1;// { dg-error "incomplete type and cannot be defined" }

gcc/testsuite/g++.dg/cpp0x/gen-attrs-17.C

@@ -0,0 +1,19 @@
+// { dg-do compile { target c++11 } }
+// Origin: Benjamin Kosnik <bkoz at gcc dot gnu dot org>
+// PR c++/17743: Attributes applied to typedefs.
+
+struct A {
+  typedef char layout_type[sizeof(double)]
+  [[gnu::aligned(alignof(double))]];
+  layout_type data;
+};
+
+struct B {
+  typedef char layout_type[sizeof(double)];
+  layout_type data  [[gnu::aligned(alignof(double))]];
+};
+
+template<bool> struct StaticAssert;
+template<> struct StaticAssert<true> {};
+
+StaticAssert<alignof(A) == alignof(B)> a1;

gcc/testsuite/g++.dg/cpp0x/gen-attrs-18.C

@@ -0,0 +1,10 @@
+// PR c++/17542
+// Test that we warn when an attribute preceding the class-key is ignored.
+// { dg-do compile { target c++11 } }
+
+[[gnu::packed]] struct A // { dg-warning "attribute" }
+{
+  char c;
+  int x;
+  void f();
+};

gcc/testsuite/g++.dg/cpp0x/gen-attrs-19.C

@@ -0,0 +1,11 @@
+// PR c++/19739
+// { dg-do compile { target c++11 } }
+
+void Dummy() [[ , ]];
+void Dummy() {}
+
+int main (int argc, char **argv)
+{
+    Dummy();
+    return 0;
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-2-1.C

@@ -0,0 +1,3 @@
+// { dg-do compile { target c++11 } }
+
+struct [[gnu::unused]] A {};

gcc/testsuite/g++.dg/cpp0x/gen-attrs-2.C

@@ -0,0 +1,11 @@
+// { dg-do compile { target c++11 } }
+
+struct [[gnu::packed]] A
+{
+  void f () const;
+};
+
+void
+A::f () const
+{
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-20.C

@@ -0,0 +1,22 @@
+// { dg-do compile { target c++11 } }
+// { dg-options "-g" }
+// Origin: <jan at etpmod dot phys dot tue dot nl>
+// PR c++/19508: avoid attributes for template parameters
+
+template <typename T>
+struct BVector
+{
+  typedef T T2;
+    typedef T value_type [[gnu::aligned(8)]];    // { dg-bogus "attribute" "attribute" }
+    typedef T2 value_type2 [[gnu::aligned(8)]];  // { dg-bogus "attribute" "attribute" }
+  value_type v;
+};
+BVector<int> m;
+
+template <template <class> class T>
+struct BV2
+{
+    typedef T<float> value_type [[gnu::aligned(8)]]; // { dg-bogus "attribute" "attribute" }
+  value_type v;
+};
+BV2<BVector> m2;

gcc/testsuite/g++.dg/cpp0x/gen-attrs-21.C

@@ -0,0 +1,21 @@
+// PR c++/20763
+// { dg-do compile { target c++11 } }
+
+typedef void *voidp;
+
+struct S
+{
+  char a;
+  voidp b [[gnu::aligned (16)]];
+};
+
+struct T
+{
+  char a;
+  void * b [[gnu::aligned (16)]];
+};
+
+static_assert (sizeof (S) == sizeof (T),
+	       "struct S and T should have the same size");
+
+static_assert (sizeof (S) == 32, "sizeof (S) == 8 + 16 + 8");

gcc/testsuite/g++.dg/cpp0x/gen-attrs-22.C

@@ -0,0 +1,7 @@
+// PR c++/27648
+// { dg-do compile { target c++11 } }
+
+void f()
+{
+  static_cast<float *[[gnu::unused]]>(0); // { dg-warning "ignored" }
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-23.C

@@ -0,0 +1,11 @@
+// PR c++/28112
+// { dg-do compile { target c++11 } }
+
+int i       [[gnu::init_priority(;)]];  // { dg-error "before" }
+int j       [[gnu::vector_size(;)]];    // { dg-error "before" }
+int k       [[gnu::visibility(;)]];     // { dg-error "before" }
+struct A {} [[gnu::aligned(;)]];        // { dg-error "before" }
+struct B {} [[gnu::mode(;)]];           // { dg-error "before" }
+void foo()  [[gnu::alias(;)]];          // { dg-error "before" }
+void bar()  [[gnu::nonnull(;)]];        // { dg-error "before" }
+void baz()  [[gnu::section(;)]];        // { dg-error "before" }

gcc/testsuite/g++.dg/cpp0x/gen-attrs-24.C

@@ -0,0 +1,4 @@
+// PR c++/28387
+// { dg-do compile { target c++11 } }
+
+enum [[gnu::unused]] E;  // { dg-error "without previous declaration" }

gcc/testsuite/g++.dg/cpp0x/gen-attrs-25.C

@@ -0,0 +1,12 @@
+// PR c++/28559
+// { dg-do compile { target c++11 } }
+
+template<typename T> struct A
+{
+  struct B;
+};
+
+struct C
+{
+  template<typename T> friend struct [[gnu::packed]] A<T>::B; // { dg-warning "uninstantiated" }
+};

gcc/testsuite/g++.dg/cpp0x/gen-attrs-26.C

@@ -0,0 +1,15 @@
+// PR c++/28659
+// The attribute was causing us to get confused in merge_types when
+// combining the template type with an uninstantiated version.
+// { dg-do compile { target c++11 } }
+
+template<class T>
+struct [[gnu::aligned(1)]] A
+{
+  A& operator=(const A &t);
+};
+
+template<class T>
+A<T>& A<T>::operator=(const A<T> &t)
+{
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-27.C

@@ -0,0 +1,6 @@
+//PR c++/29980
+// { dg-do compile { target c++11 } }
+
+struct A { typedef int X; };            // { dg-message "previous declaration" }
+
+struct [[gnu::unused]] A::X;    // { dg-error "typedef-name" }

gcc/testsuite/g++.dg/cpp0x/gen-attrs-28.C

@@ -0,0 +1,13 @@
+// PR c++/28558
+// { dg-options "" }
+// { dg-do compile { target c++11 } }
+
+struct A
+{
+  A(int) { }
+};
+
+int main()
+{
+    A a = (A [[gnu::unused]])0; // { dg-warning "attribute" }
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-29.C

@@ -0,0 +1,10 @@
+// PR c++/33506
+// { dg-do compile { target c++11 } }
+
+extern int f1 [[gnu::warn_unused_result]] (char *) ;
+extern int f2 [[gnu::warn_unused_result]] (char *) throw () ;
+extern int f2 (char *) throw ();
+
+extern int f3 [[gnu::nonnull (1)]] (char *) ;
+extern int f4 [[gnu::nonnull (1)]] (char *) throw ();
+extern int f4 (char *) throw ();

gcc/testsuite/g++.dg/cpp0x/gen-attrs-3.C

@@ -0,0 +1,22 @@
+// Test that attributes work in a variety of situations.
+// { dg-options "-O -ftrack-macro-expansion=0" }
+// { dg-do run { target c++11 } }
+
+#define attrib [[gnu::mode (QI)]]
+#define gnu_attrib __attribute((mode (QI)))
+
+attrib signed int a;
+static unsigned int b attrib;
+
+int foo(attrib int o)
+{
+  return (sizeof (a) != 1
+	  || sizeof (b) != 1
+	  || sizeof (o) != 1
+	  || sizeof ((gnu_attrib signed int) b) != 1);
+}
+
+int main ()
+{
+  return foo (42);
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-30.C

@@ -0,0 +1,9 @@
+// { dg-do compile { target c++11 } }
+// PR c++/35074
+
+template<typename T> struct A
+{
+  void foo() const;
+} [[gnu::aligned(4)]]; // { dg-warning "ignored" }
+
+template<typename T> void A<T>::foo() const {}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-31.C

@@ -0,0 +1,16 @@
+// PR c++/35097
+// { dg-do compile { target c++11 } }
+
+template<int> struct A;
+
+template<> struct A<0>
+{
+  typedef int X [[gnu::aligned(4)]];
+};
+
+template<typename T> void foo(const A<0>::X&, T);
+
+void bar()
+{
+  foo(A<0>::X(), 0);
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-32.C

@@ -0,0 +1,37 @@
+// PR c++/35315
+// { dg-do compile { target c++11 } }
+
+typedef union { int i; } U [[gnu::transparent_union]]; // { dg-warning "ignored" }
+
+static void foo(U) {}
+static void foo(int) {}
+
+void bar()
+{
+  foo(0);
+}
+
+typedef union U1 { int i; } U2 [[gnu::transparent_union]]; // { dg-warning "ignored" }
+
+static void foo2(U1) {}		// { dg-error "previously defined" }
+static void foo2(U2) {}		// { dg-error "redefinition" }
+
+void bar2(U1 u1, U2 u2)
+{
+  foo2(u1);
+  foo2(u2);
+}
+
+// PR c++/36410
+struct A
+{
+  typedef union [[gnu::transparent_union]]
+  {
+    int i;
+  } B;
+};
+
+void foo(A::B b)
+{
+  b.i;
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-33.C

@@ -0,0 +1,19 @@
+// PR c++/35546
+// { dg-do compile { target c++11 } }
+// { dg-options "-g" }
+
+template <int N>
+struct T
+{
+  void foo [[gnu::format (printf,2,3)]] (char const * ...);
+};
+
+template struct T<3>;
+
+template <typename T>
+struct U
+{
+  typedef T V [[gnu::mode (SI)]];
+};
+
+U<int>::V v;

gcc/testsuite/g++.dg/cpp0x/gen-attrs-34.C

@@ -0,0 +1,19 @@
+// PR c/37171
+// { dg-do compile { target c++11 } }
+// { dg-options "-O2 -fdump-tree-optimized" }
+
+unsigned int f1 [[gnu::const]] ();
+unsigned int f2 [[gnu::__const]] () ;
+unsigned int f3 [[gnu::__const__]] () ;
+
+unsigned int f4 ()
+{
+  return f1 () + f1 () + f1 () + f1 ()
+	 + f2 () + f2 () + f2 () + f2 ()
+	 + f3 () + f3 () + f3 () + f3 ();
+}
+
+// { dg-final { scan-tree-dump-times "= f1 \\(\\)" 1 "optimized" } }
+// { dg-final { scan-tree-dump-times "= f2 \\(\\)" 1 "optimized" } }
+// { dg-final { scan-tree-dump-times "= f3 \\(\\)" 1 "optimized" } }
+// { dg-final { cleanup-tree-dump "optimized" } }

gcc/testsuite/g++.dg/cpp0x/gen-attrs-35.C

@@ -0,0 +1,20 @@
+// { dg-do compile { target i?86-*-* x86_64-*-* } }
+// { dg-options "-O3 -msse2 -std=c++11" }
+// { dg-require-effective-target sse2 }
+
+// You can make NON-template typedefs with a large alignment.
+typedef double AlignedDoubleType [[gnu::aligned(16)]];
+
+template <typename RealType>
+RealType f(const RealType* p)
+{
+  // But if you use a template parameter it complains.
+  typedef RealType AlignedRealType [[gnu::aligned(16)]];
+
+  return p[0];
+}
+
+double f2(const double* p)
+{
+  return f<double>(p);
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-36-1.C

@@ -0,0 +1,11 @@
+// { dg-do compile { target c++11 } }
+
+struct S;
+
+typedef int (*F [[gnu::warn_unused_result]]) (int);
+
+typedef int (*F2 [[gnu::warn_unused_result]]) (int);
+
+typedef int (S::*F3 [[gnu::warn_unused_result]]) (int); // { dg-warning "only applies to function types" }
+
+typedef int [[gnu::warn_unused_result]] (*F5) (int); // { dg-warning "ignored" }

gcc/testsuite/g++.dg/cpp0x/gen-attrs-36.C

@@ -0,0 +1,23 @@
+// PR c++/43031
+// { dg-options "-std=c++11 -pedantic" }
+// { dg-do compile { target { { i?86-*-* x86_64-*-* } && ia32 } } }
+
+class T;
+class L { };
+class P : public L
+{
+  typedef void (T::* [[gnu::__stdcall__]] F2) (L*); // { dg-warning "only applies to function types" }
+  typedef void (T::*F) (L*) [[gnu::__stdcall__]];
+  void f(bool aAdd);
+};
+
+class T
+{
+public:
+  virtual void  A(L *listener) [[gnu::__stdcall__]] = 0;
+  virtual void R(L *listener)  [[gnu::__stdcall__]] = 0;
+};
+void P::f(bool aAdd)
+{
+  F addRemoveEventListener = (aAdd ? &T::A : &T::R);
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-37.C

@@ -0,0 +1,15 @@
+// PR c++/43093
+// { dg-options "-std=c++11 -pedantic" }
+// { dg-do compile { target { { i?86-*-* x86_64-*-* } && ia32 } } }
+
+struct S {
+  int x;
+  S(const S &s) {}
+};
+
+S getS() [[gnu::__stdcall__]];
+
+void test()
+{
+  S s = getS();
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-38.C

@@ -0,0 +1,12 @@
+// { dg-do compile { target c++11 } }
+// PR c++/36625
+
+template <int N>
+struct A {
+  struct S { short f[3]; } [[gnu::aligned (N)]]; // { dg-warning "ignored" }
+};
+
+int main ()
+{
+  A<4>::S s;
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-39-1.C

@@ -0,0 +1,10 @@
+// { dg-do compile { target c++11 } }
+
+int fragile_block(void) {
+  typedef 
+  [[gnu::aligned (16)]] // { dg-warning "ignored" }
+  struct  {
+    int i;
+  } XmmUint16;
+  return 0;
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-39.C

@@ -0,0 +1,10 @@
+// PR debug/43370
+// { dg-do compile { target c++11 } }
+// { dg-options "-g" }
+
+int fragile_block(void) {
+  typedef struct [[gnu::aligned (16)]] {
+    int i;
+  } XmmUint16;
+  return 0;
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-4.C

@@ -0,0 +1,30 @@
+// { dg-options "-std=c++11 -Wunused -pedantic-errors" }
+// { dg-do compile }
+// Test for syntax support of various attribute permutations.
+
+int
+[[gnu::noreturn]] // { dg-warning "ignored" }
+one
+[[gnu::unused]]
+(void);
+
+int one_third [[gnu::noreturn]] [[gnu::unused]] (void);
+
+int [[gnu::unused]] one_half(); // { dg-warning "ignored" }
+
+static
+[[gnu::noreturn]] // { dg-warning "ignored" }
+void two [[gnu::unused]] (void) {}
+
+
+
+[[gnu::unused]]
+int
+five(void)
+[[gnu::noreturn]] // { dg-warning "ignored" }
+{}
+
+[[gnu::noreturn]]
+void
+six (void)
+;

gcc/testsuite/g++.dg/cpp0x/gen-attrs-40.C

@@ -0,0 +1,5 @@
+// PR c++/46803
+// { dg-do compile { target c++11 } }
+
+int strftime(char *, int, const char *, const struct tm *)
+        [[gnu::__bounded__(__string__,1,2)]]; // { dg-warning "ignored" }

gcc/testsuite/g++.dg/cpp0x/gen-attrs-41.C

@@ -0,0 +1,20 @@
+// PR c++/45267
+// { dg-do compile { target c++11 } }
+// { dg-options "-O" }
+
+template<typename T> struct Vector {
+  Vector(long long x);
+  inline Vector<T> operator<< [[gnu::always_inline]] (int x) const;
+};
+long long bar (long long);
+template<> inline Vector<int> Vector<int>::operator<<(int x) const {
+  return bar(x);
+}
+bool b;
+int main() {
+  Vector<int> a(1);
+  if ((a << 2), b) {
+    a << 2;
+    throw 1;
+  }
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-42.C

@@ -0,0 +1,13 @@
+// { dg-options "-std=c++11 -pedantic" }
+// { dg-do compile { target { i?86-*-* && ilp32 } } }
+
+struct A {
+  [[gnu::fastcall]]
+  void f();
+};
+
+int main()
+{
+    typedef void (A::*FP)();
+    FP fp[] = {&A::f};		// { dg-error "cannot convert" }
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-43.C

@@ -0,0 +1,4 @@
+// { dg-do compile { target c++11 } }
+template <class T> struct A { };
+
+template [[gnu::packed]] struct A<int>;  // { dg-warning "ignored in explicit instantiation" }

gcc/testsuite/g++.dg/cpp0x/gen-attrs-44.C

@@ -0,0 +1,3 @@
+// PR c++/52671
+// { dg-do compile { target c++11 } }
+[[gnu::deprecated]] enum E { E0 };	// { dg-warning "ignored in declaration" }

gcc/testsuite/g++.dg/cpp0x/gen-attrs-45.C

@@ -0,0 +1,4 @@
+// PR c++/52906
+// { dg-do compile { target c++11 } }
+
+[[gnu::deprecated]]; // { dg-error "does not declare anything" }

gcc/testsuite/g++.dg/cpp0x/gen-attrs-46.C

@@ -0,0 +1,5 @@
+// PR c++/40821
+// { dg-do compile { target c++11 } }
+
+struct [[gnu::aligned(8)] S1 { int i; }; // { dg-error "" }
+struct  [aligned(8)  S2 { int i; }; // { dg-error "" }

gcc/testsuite/g++.dg/cpp0x/gen-attrs-47-1.C

@@ -0,0 +1,8 @@
+// { dg-do compile { target c++11 } }
+int
+foo ()
+{
+  int i [[and, bitor, xor_eq, compl, bitand]]; // { dg-warning "ignored" }
+  i = 0;
+  return i;
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-47.C

@@ -0,0 +1,13 @@
+// { dg-do compile { target c++11 } }
+// Example taken from dcl.attr.grammar:
+
+int p[10];
+void f()
+{
+    int x = 42, y[5];
+    /* Here, the '[[' should have introduced an attribute, on a
+       lambda invocation an array subscripting expression.  */
+    int(p[[x] { return x; }()]); // { dg-error "expected|consecutive" }
+    /* Likewise, the '[[gnu::' is invalid here.  */
+    y[[] { return 2; }()] = 2; // { dg-error "expected|consecutive" }
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-48.C

@@ -0,0 +1,17 @@
+// { dg-do compile { target c++11 } }
+
+typedef char layout_type;
+
+struct A {
+  layout_type member alignas (double);
+};
+
+static_assert (alignof (A) == alignof (double),
+	       "alignment of struct A must be alignof (double)");
+
+struct alignas (alignof (long double)) B {
+  layout_type member;
+};
+
+static_assert (alignof (B) == alignof (long double),
+	       "alignment of struct A must be alignof (double double)");

gcc/testsuite/g++.dg/cpp0x/gen-attrs-49.C

@@ -0,0 +1,17 @@
+// { dg-do compile { target c++11 } }
+
+typedef char layout_type;
+
+template<class> struct A {
+  layout_type member alignas (double);
+};
+
+static_assert (alignof (A<int>) == alignof (double),
+	       "alignment of struct A must be alignof (double)");
+
+template<class> struct alignas (alignof (long double)) B {
+  layout_type member;
+};
+
+static_assert (alignof (B<int>) == alignof (long double),
+	       "alignment of struct A must be alignof (double double)");

gcc/testsuite/g++.dg/cpp0x/gen-attrs-5.C

@@ -0,0 +1,23 @@
+// { dg-do compile { target c++11 } }
+//
+// There were two related problems here, depending on the vintage.  At
+// one time:
+//
+//    typedef struct A { ... } A [[gnu::aligned (16)]];
+//
+// would cause original_types to go into an infinite loop.  At other
+// times, the attributes applied to an explicit typedef would be lost
+// (check_b3 would have a negative size).
+
+// First check that the declaration is accepted and has an effect.
+typedef struct A { int i; } A [[gnu::aligned (16)]];
+int check_A[alignof (A) >= 16 ? 1 : -1];
+
+// Check that the alignment is only applied to the typedef.
+struct B { int i; };
+struct B b1;
+typedef struct B B [[gnu::aligned (16)]];
+struct B b2;
+B b3;
+int check_b1[__alignof__ (b1) == __alignof__ (b2) ? 1 : -1];
+int check_b3[__alignof__ (b3) >= 16 ? 1 : -1];

gcc/testsuite/g++.dg/cpp0x/gen-attrs-50.C

@@ -0,0 +1,22 @@
+// { dg-do compile { target c++11 } }
+
+typedef char layout_type;
+
+template<class> struct A {
+  layout_type member alignas (double) alignas (int);
+};
+
+// Here, the spec says that A<int> should have the stricter alignment,
+// so that would be the alignment of 'double', not 'int'.
+static_assert (alignof (A<int>) == alignof (double),
+	       "alignment of struct A must be alignof (double)");
+
+template<class> struct alignas (1) alignas (alignof (long double)) B {
+  layout_type member;
+};
+
+// Similarly, the B<int> should have the stricter alignment, so that would
+// so that would be the alignment of 'long double', not '1'.
+static_assert (alignof (B<int>) == alignof (long double),
+	       "alignment of struct A must be alignof (double double)");
+

gcc/testsuite/g++.dg/cpp0x/gen-attrs-51.C

@@ -0,0 +1,9 @@
+// { dg-do compile { target c++11 } }
+
+typedef char layout_type;
+struct A
+{
+    layout_type member [[gnu::aligned (16)]];
+};
+
+static_assert (sizeof (A) == 16, "Alignment should be 16");

gcc/testsuite/g++.dg/cpp0x/gen-attrs-52.C

@@ -0,0 +1,21 @@
+// { dg-do compile { target c++11 } }
+
+struct A {int i;}  a [[gnu::aligned(16)]];
+struct B {int i;} __attribute__((aligned(16))) b;
+
+int
+main ()
+{
+ A aa;
+ B bb;
+
+ static_assert (sizeof (a) == 4, "sizeof (a) should be 4");
+ static_assert (sizeof (b) == 16, "sizeof (b) should be 16");
+ static_assert (sizeof (aa) == 4, "sizeof (aa) should be 4");
+ static_assert (sizeof (bb) == 16, "sizeof (bb) should be 16");
+
+ static_assert (__alignof__  (a) == 16, "alignof (a) should be 16");
+ static_assert (__alignof__  (b) == 16, "alignof (b) should be 16");
+ static_assert (__alignof__  (aa) == 4, "alignof (aa) should be 4");
+ static_assert (__alignof__  (bb) == 16, "alignof (bb) should be 16");
+}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-53.C

@@ -0,0 +1,39 @@
+// { dg-do compile { target c++11 } }
+
+int
+toto ()
+{
+  [[gnu::unused]] good:
+    return 0;
+}
+
+int
+foo ()
+{
+  [[gnu::unused]] good:
+    int i = 0;
+
+  // A C++11 attribute at the beginning of the return statement is
+  // syntactically correct, appertains to the return statement (not to
+  // the label) but is currently ignored by this implementation.
+ good_ignored : [[gnu::unused]] // { dg-warning "attributes at the beginning of statement are ignored" }
+    return i;
+}
+
+int
+bar ()
+{
+  // A GNU attribute after the label appertains to the label.
+ good: __attribute__((unused));
+  return 0;
+}
+
+int
+baz ()
+{
+  // The c++ attribute after the label appertains to the (empty)
+  // statement.
+ bad: [[gnu::unused]]; // { dg-warning "attributes at the beginning of statement are ignored" }
+  return 0;
+}
+

gcc/testsuite/g++.dg/cpp0x/gen-attrs-6.C

@@ -0,0 +1,20 @@
+// Copyright (C) 2002  Free Software Foundation.
+//
+// Test that the nothrow attribute is working correctly.
+//
+// Written by Richard Henderson, 26 May 2002.
+
+// { dg-do link { target c++11} }
+extern void foo [[gnu::nothrow]] ();
+extern void link_error();
+
+int main()
+{
+  try {
+    foo();
+  } catch (...) {
+    link_error();
+  }
+}
+
+void foo() { }

gcc/testsuite/g++.dg/cpp0x/gen-attrs-7.C

@@ -0,0 +1,4 @@
+// { dg-do compile { target c++11 } }
+// { dg-options "-Wunused-parameter" }
+
+void f (int i [[gnu::__unused__]]) {}

gcc/testsuite/g++.dg/cpp0x/gen-attrs-8.C

@@ -0,0 +1,6 @@
+// { dg-options "-std=c++11 -pedantic" }
+// { dg-do compile { target { { i?86-*-* x86_64-*-* } && ia32 } } }
+
+extern int * ([[gnu::stdcall]] *fooPtr)( void); // { dg-error "expected" }
+int * [[gnu::stdcall]] myFn01( void) { return 0; }// { dg-warning "attribute only applies to function types" }
+

gcc/testsuite/g++.dg/cpp0x/gen-attrs-9.C

@@ -0,0 +1,12 @@
+// { dg-do compile { target c++11 } }
+
+class C;
+struct S;
+union U;
+enum e {};
+enum [[gnu::unused]] e;	// { dg-warning "already defined" }
+
+struct [[gnu::unused]] B *p;	//  { dg-warning "attributes" }
+
+template <class T> struct A { };
+struct [[gnu::unused]] A<int>;	//  { dg-warning "attributes" }

gcc/tree.c

@@ -4350,7 +4350,7 @@ comp_type_attributes (const_tree type1, const_tree type2)
       const struct attribute_spec *as;
       const_tree attr;
 
-      as = lookup_attribute_spec (TREE_PURPOSE (a));
+      as = lookup_attribute_spec (get_attribute_name (a));
       if (!as || as->affects_type_identity == false)
         continue;
 
@@ -4364,7 +4364,7 @@ comp_type_attributes (const_tree type1, const_tree type2)
 	{
 	  const struct attribute_spec *as;
 
-	  as = lookup_attribute_spec (TREE_PURPOSE (a));
+	  as = lookup_attribute_spec (get_attribute_name (a));
 	  if (!as || as->affects_type_identity == false)
 	    continue;
 
@@ -5287,11 +5287,12 @@ private_lookup_attribute (const char *attr_name, size_t attr_len, tree list)
 {
   while (list)
     {
-      size_t ident_len = IDENTIFIER_LENGTH (TREE_PURPOSE (list));
+      size_t ident_len = IDENTIFIER_LENGTH (get_attribute_name (list));
 
       if (ident_len == attr_len)
 	{
-	  if (strcmp (attr_name, IDENTIFIER_POINTER (TREE_PURPOSE (list))) == 0)
+	  if (!strcmp (attr_name,
+		       IDENTIFIER_POINTER (get_attribute_name (list))))
 	    break;
 	}
       /* TODO: If we made sure that attributes were stored in the
@@ -5299,7 +5300,7 @@ private_lookup_attribute (const char *attr_name, size_t attr_len, tree list)
 	 to '__text__') then we could avoid the following case.  */
       else if (ident_len == attr_len + 4)
 	{
-	  const char *p = IDENTIFIER_POINTER (TREE_PURPOSE (list));
+	  const char *p = IDENTIFIER_POINTER (get_attribute_name (list));
 	  if (p[0] == '_' && p[1] == '_'
 	      && p[ident_len - 2] == '_' && p[ident_len - 1] == '_'
 	      && strncmp (attr_name, p + 2, attr_len) == 0)
@@ -5329,10 +5330,11 @@ lookup_ident_attribute (tree attr_identifier, tree list)
 
   while (list)
     {
-      gcc_checking_assert (TREE_CODE (TREE_PURPOSE (list)) == IDENTIFIER_NODE);
+      gcc_checking_assert (TREE_CODE (get_attribute_name (list))
+			   == IDENTIFIER_NODE);
 
       /* Identifiers can be compared directly for equality.  */
-      if (attr_identifier == TREE_PURPOSE (list))
+      if (attr_identifier == get_attribute_name (list))
 	break;
 
       /* If they are not equal, they may still be one in the form
@@ -5342,11 +5344,11 @@ lookup_ident_attribute (tree attr_identifier, tree list)
 	 the fact that we're comparing identifiers. :-)  */
       {
 	size_t attr_len = IDENTIFIER_LENGTH (attr_identifier);
-	size_t ident_len = IDENTIFIER_LENGTH (TREE_PURPOSE (list));
+	size_t ident_len = IDENTIFIER_LENGTH (get_attribute_name (list));
 
 	if (ident_len == attr_len + 4)
 	  {
-	    const char *p = IDENTIFIER_POINTER (TREE_PURPOSE (list));
+	    const char *p = IDENTIFIER_POINTER (get_attribute_name (list));
 	    const char *q = IDENTIFIER_POINTER (attr_identifier);
 	    if (p[0] == '_' && p[1] == '_'
 		&& p[ident_len - 2] == '_' && p[ident_len - 1] == '_'
@@ -5355,7 +5357,7 @@ lookup_ident_attribute (tree attr_identifier, tree list)
 	  }
 	else if (ident_len + 4 == attr_len)
 	  {
-	    const char *p = IDENTIFIER_POINTER (TREE_PURPOSE (list));
+	    const char *p = IDENTIFIER_POINTER (get_attribute_name (list));
 	    const char *q = IDENTIFIER_POINTER (attr_identifier);
 	    if (q[0] == '_' && q[1] == '_'
 		&& q[attr_len - 2] == '_' && q[attr_len - 1] == '_'
@@ -5385,7 +5387,7 @@ remove_attribute (const char *attr_name, tree list)
       tree l = *p;
       /* TODO: If we were storing attributes in normalized form, here
 	 we could use a simple strcmp().  */
-      if (private_is_attribute_p (attr_name, attr_len, TREE_PURPOSE (l)))
+      if (private_is_attribute_p (attr_name, attr_len, get_attribute_name (l)))
 	*p = TREE_CHAIN (l);
       else
 	p = &TREE_CHAIN (l);
@@ -5422,9 +5424,11 @@ merge_attributes (tree a1, tree a2)
 	  for (; a2 != 0; a2 = TREE_CHAIN (a2))
 	    {
 	      tree a;
-	      for (a = lookup_ident_attribute (TREE_PURPOSE (a2), attributes);
+	      for (a = lookup_ident_attribute (get_attribute_name (a2),
+					       attributes);
 		   a != NULL_TREE && !attribute_value_equal (a, a2);
-		   a = lookup_ident_attribute (TREE_PURPOSE (a2), TREE_CHAIN (a)))
+		   a = lookup_ident_attribute (get_attribute_name (a2),
+					       TREE_CHAIN (a)))
 		;
 	      if (a == NULL_TREE)
 		{
@@ -6346,7 +6350,7 @@ attribute_hash_list (const_tree list, hashval_t hashcode)
   for (tail = list; tail; tail = TREE_CHAIN (tail))
     /* ??? Do we want to add in TREE_VALUE too? */
     hashcode = iterative_hash_object
-      (IDENTIFIER_HASH_VALUE (TREE_PURPOSE (tail)), hashcode);
+      (IDENTIFIER_HASH_VALUE (get_attribute_name (tail)), hashcode);
   return hashcode;
 }
 
@@ -6383,7 +6387,7 @@ attribute_list_contained (const_tree l1, const_tree l2)
   /* Maybe the lists are similar.  */
   for (t1 = l1, t2 = l2;
        t1 != 0 && t2 != 0
-        && TREE_PURPOSE (t1) == TREE_PURPOSE (t2)
+        && get_attribute_name (t1) == get_attribute_name (t2)
         && TREE_VALUE (t1) == TREE_VALUE (t2);
        t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2))
     ;
@@ -6398,9 +6402,9 @@ attribute_list_contained (const_tree l1, const_tree l2)
       /* This CONST_CAST is okay because lookup_attribute does not
 	 modify its argument and the return value is assigned to a
 	 const_tree.  */
-      for (attr = lookup_ident_attribute (TREE_PURPOSE (t2), CONST_CAST_TREE(l1));
+      for (attr = lookup_ident_attribute (get_attribute_name (t2), CONST_CAST_TREE(l1));
 	   attr != NULL_TREE && !attribute_value_equal (t2, attr);
-	   attr = lookup_ident_attribute (TREE_PURPOSE (t2), TREE_CHAIN (attr)))
+	   attr = lookup_ident_attribute (get_attribute_name (t2), TREE_CHAIN (attr)))
 	;
 
       if (attr == NULL_TREE)

gcc/tree.h

@@ -4903,12 +4903,12 @@ struct attribute_spec
 {
   /* The name of the attribute (without any leading or trailing __),
      or NULL to mark the end of a table of attributes.  */
-  const char *const name;
+  const char *name;
   /* The minimum length of the list of arguments of the attribute.  */
-  const int min_length;
+  int min_length;
   /* The maximum length of the list of arguments of the attribute
      (-1 for no maximum).  */
-  const int max_length;
+  int max_length;
   /* Whether this attribute requires a DECL.  If it does, it will be passed
      from types of DECLs, function return types and array element types to
      the DECLs, function types and array types respectively; but when
@@ -4916,15 +4916,15 @@ struct attribute_spec
      a warning.  (If greater control is desired for a given attribute,
      this should be false, and the flags argument to the handler may be
      used to gain greater control in that case.)  */
-  const bool decl_required;
+  bool decl_required;
   /* Whether this attribute requires a type.  If it does, it will be passed
      from a DECL to the type of that DECL.  */
-  const bool type_required;
+  bool type_required;
   /* Whether this attribute requires a function (or method) type.  If it does,
      it will be passed from a function pointer type to the target type,
      and from a function return type (which is not itself a function
      pointer type) to the function type.  */
-  const bool function_type_required;
+  bool function_type_required;
   /* Function to handle this attribute.  NODE points to the node to which
      the attribute is to be applied.  If a DECL, it should be modified in
      place; if a TYPE, a copy should be created.  NAME is the name of the
@@ -4939,10 +4939,10 @@ struct attribute_spec
      otherwise the return value should be NULL_TREE.  This pointer may be
      NULL if no special handling is required beyond the checks implied
      by the rest of this structure.  */
-  tree (*const handler) (tree *node, tree name, tree args,
+  tree (*handler) (tree *node, tree name, tree args,
 		   int flags, bool *no_add_attrs);
   /* Specifies if attribute affects type's identity.  */
-  const bool affects_type_identity;
+  bool affects_type_identity;
 };
 
 /* Flags that may be passed in the third argument of decl_attributes, and
@@ -4967,7 +4967,9 @@ enum attribute_flags
   /* The attributes are being applied by default to a library function whose
      name indicates known behavior, and should be silently ignored if they
      are not in fact compatible with the function type.  */
-  ATTR_FLAG_BUILT_IN = 16
+  ATTR_FLAG_BUILT_IN = 16,
+  /* A given attribute has been parsed as a C++-11 attribute.  */
+  ATTR_FLAG_CXX11 = 32
 };
 
 /* Default versions of target-overridable functions.  */
@@ -6054,6 +6056,8 @@ extern bool must_pass_in_stack_var_size_or_pad (enum machine_mode, const_tree);
 /* In attribs.c.  */
 
 extern const struct attribute_spec *lookup_attribute_spec (const_tree);
+extern const struct attribute_spec *lookup_scoped_attribute_spec (const_tree,
+								  const_tree);
 
 extern void init_attributes (void);
 
@@ -6067,6 +6071,12 @@ extern void init_attributes (void);
    a decl attribute to the declaration rather than to its type).  */
 extern tree decl_attributes (tree *, tree, int);
 
+extern bool cxx11_attribute_p (const_tree);
+
+extern tree get_attribute_name (const_tree);
+
+extern tree get_attribute_namespace (const_tree);
+
 extern void apply_tm_attr (tree, tree);
 
 /* In stor-layout.c */