c-family PATCH for c++/90953 - ICE with -Wmissing-format-attribute

[Marek Polacek]

These functions are using TREE_PURPOSE to get the attribute name,
which is breaking now that we preserve the C++11-style attribute
format past decl_attributes.  So use get_attribute_name which can
handle both formats of attributes.

Bootstrapped/regtested on x86_64-linux, ok for trunk?

2019-06-21  Marek Polacek  <polacek@redhat.com>

	PR c++/90953 - ICE with -Wmissing-format-attribute.
	* c-common.c (check_function_arguments_recurse): Use
	get_attribute_name.
	(check_missing_format_attribute): Likewise.

	* g++.dg/warn/miss-format-7.C: New test.

diff --git gcc/c-family/c-common.c gcc/c-family/c-common.c
index 4057be3aaed..f5627040067 100644
--- gcc/c-family/c-common.c
+++ gcc/c-family/c-common.c
@@ -5753,7 +5753,7 @@ check_function_arguments_recurse (void (*callback)
       for (attrs = TYPE_ATTRIBUTES (type);
 	   attrs;
 	   attrs = TREE_CHAIN (attrs))
-	if (is_attribute_p ("format_arg", TREE_PURPOSE (attrs)))
+	if (is_attribute_p ("format_arg", get_attribute_name (attrs)))
 	  {
 	    tree inner_arg;
 	    tree format_num_expr;
@@ -7601,13 +7601,13 @@ check_missing_format_attribute (tree ltype, tree rtype)
   tree ra;
 
   for (ra = TYPE_ATTRIBUTES (ttr); ra; ra = TREE_CHAIN (ra))
-    if (is_attribute_p ("format", TREE_PURPOSE (ra)))
+    if (is_attribute_p ("format", get_attribute_name (ra)))
       break;
   if (ra)
     {
       tree la;
       for (la = TYPE_ATTRIBUTES (ttl); la; la = TREE_CHAIN (la))
-	if (is_attribute_p ("format", TREE_PURPOSE (la)))
+	if (is_attribute_p ("format", get_attribute_name (la)))
 	  break;
       return !la;
     }
diff --git gcc/testsuite/g++.dg/warn/miss-format-7.C gcc/testsuite/g++.dg/warn/miss-format-7.C
new file mode 100644
index 00000000000..ac892dcec6d
--- /dev/null
+++ gcc/testsuite/g++.dg/warn/miss-format-7.C
@@ -0,0 +1,29 @@
+// PR c++/90953 - ICE with -Wmissing-format-attribute.
+// { dg-do compile { target c++11 } }
+// { dg-options "-Wmissing-format-attribute" }
+
+namespace std {
+union [[gnu::may_alias]] _Any_data{};
+enum _Manager_operation { __get_type_info };
+template <typename> class A;
+class B {
+  typedef bool (*_Manager_type)(_Any_data, const _Any_data &,
+                                _Manager_operation);
+public:
+  _Any_data _M_functor;
+  _Manager_type _M_manager;
+};
+
+struct type_info { } t;
+
+template <typename _Res, typename... _ArgTypes>
+class A<_Res(_ArgTypes...)> : B {
+  const type_info &target_type() const noexcept;
+};
+template <typename _Res, typename... _ArgTypes>
+const type_info &A<_Res(_ArgTypes...)>::target_type() const noexcept {
+  _Any_data __typeinfo_result;
+  _M_manager(__typeinfo_result, _M_functor, __get_type_info);
+  return t;
+}
+} // namespace std