C++ PATCH for c++/59633 (ICE with vector attribute on naming typedef)

[Jason Merrill <jason at redhat dot com>]

The vector_size attribute changes an ENUM_TYPE into a VECTOR_TYPE, so it 
is obviously unsuitable for a typedef that gives the enum a name for 
linkage purposes.  This patch allows the typedef, but makes it no longer 
a name for linkage purposes.

Tested x86_64-pc-linux-gnu, applying to trunk (walk_type_fields hunk 
under obvious rule).
commit 3cf87cf8a33ba387d8468e47dbc87e87c0c3b722
Author: Jason Merrill <jason@redhat.com>
Date:   Thu Jan 30 00:27:17 2014 -0500

    	PR c++/59633
    gcc/
    	* tree.c (walk_type_fields): Handle VECTOR_TYPE.
    gcc/cp/
    	* decl2.c (attributes_naming_typedef_ok): New.
    	* cp-tree.h: Declare it.
    	* decl.c (grokdeclarator): Check it.
    	* tree.c (no_linkage_check): Handle VECTOR_TYPE.

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index ab75db8..7f46499 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -5296,6 +5296,7 @@ extern tree grokfield (const cp_declarator *, cp_decl_specifier_seq *,
 extern tree grokbitfield (const cp_declarator *, cp_decl_specifier_seq *,
 			  tree, tree);
 extern tree cp_reconstruct_complex_type		(tree, tree);
+extern bool attributes_naming_typedef_ok	(tree);
 extern void cplus_decl_attributes		(tree *, tree, int);
 extern void finish_anon_union			(tree);
 extern void cp_write_global_declarations	(void);
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index d7e5829..3652e8d 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -10216,6 +10216,7 @@ grokdeclarator (const cp_declarator *declarator,
 	  && TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
 	  && TYPE_ANONYMOUS_P (type)
 	  && declspecs->type_definition_p
+	  && attributes_naming_typedef_ok (*attrlist)
 	  && cp_type_quals (type) == TYPE_UNQUALIFIED)
 	{
 	  tree t;
diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index 58419ec..b2103c8 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -1243,6 +1243,22 @@ save_template_attributes (tree *attr_p, tree *decl_p)
     }
 }
 
+/* Return true iff ATTRS are acceptable attributes to be applied in-place
+   to a typedef which gives a previously anonymous class or enum a name for
+   linkage purposes.  */
+
+bool
+attributes_naming_typedef_ok (tree attrs)
+{
+  for (; attrs; attrs = TREE_CHAIN (attrs))
+    {
+      tree name = get_attribute_name (attrs);
+      if (is_attribute_p ("vector_size", name))
+	return false;
+    }
+  return true;
+}
+
 /* Like reconstruct_complex_type, but handle also template trees.  */
 
 tree
diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index ce41c3b..fe2ddab 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -2170,6 +2170,7 @@ no_linkage_check (tree t, bool relaxed_p)
     case ARRAY_TYPE:
     case POINTER_TYPE:
     case REFERENCE_TYPE:
+    case VECTOR_TYPE:
       return no_linkage_check (TREE_TYPE (t), relaxed_p);
 
     case OFFSET_TYPE:
diff --git a/gcc/testsuite/g++.dg/ext/vector26.C b/gcc/testsuite/g++.dg/ext/vector26.C
new file mode 100644
index 0000000..6d55158
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/vector26.C
@@ -0,0 +1,8 @@
+// PR c++/59633
+// In C++98, the definition of bar is an error.  In C++11, bar implicitly
+// gets internal linkage.
+
+typedef enum { e } T __attribute__((vector_size(8)));
+static void foo(T t) {}
+void bar (T t) {}		// { dg-error "no linkage" "" { target c++98 } }
+// { dg-final { scan-assembler-not "globl\[ \t]*_Z3bar" } }
diff --git a/gcc/tree.c b/gcc/tree.c
index 5fdd491..1d06ba7 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -10817,6 +10817,7 @@ walk_type_fields (tree type, walk_tree_fn func, void *data,
     {
     case POINTER_TYPE:
     case REFERENCE_TYPE:
+    case VECTOR_TYPE:
       /* We have to worry about mutually recursive pointers.  These can't
 	 be written in C.  They can in Ada.  It's pathological, but
 	 there's an ACATS test (c38102a) that checks it.  Deal with this