On 2/12/24 12:30, Jakub Jelinek wrote:
Hi!
The C and C++ FEs when parsing attributes already canonicalize them
(i.e. if they start with __ and end with __ substrings, we remove those).
lookup_attribute already verifies in gcc_assert that the first character
of name is not an underscore, and even lookup_scoped_attribute_spec doesn't
attempt to canonicalize the namespace it is passed. But for some historic
reason it was canonicalizing the name argument, which misbehaves when
an attribute starts with ____ and ends with ____.
I believe it is just wrong to try to canonicalize
lookup_scope_attribute_spec name attribute, it should have been
canonicalized already, in other spots where it is called it is already
canonicalized before.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
2024-02-12 Jakub Jelinek <ja...@redhat.com>
PR c++/113674
* attribs.cc (extract_attribute_substring): Remove.
(lookup_scoped_attribute_spec): Don't call it.
* c-c++-common/Wattributes-3.c: New test.
--- gcc/attribs.cc.jj 2024-01-03 11:51:39.392622088 +0100
+++ gcc/attribs.cc 2024-02-12 12:50:00.660458907 +0100
@@ -116,15 +116,6 @@ get_gnu_namespace ()
return gnu_namespace_cache;
}
-/* Return base name of the attribute. Ie '__attr__' is turned into 'attr'.
- To avoid need for copying, we simply return length of the string. */
-
-static void
-extract_attribute_substring (struct substring *str)
-{
- canonicalize_attr_name (str->str, str->length);
-}
-
/* Insert SPECS into its namespace. IGNORED_P is true iff all unknown
attributes in this namespace should be ignored for the purposes of
-Wattributes. The function returns the namespace into which the
@@ -398,7 +389,6 @@ lookup_scoped_attribute_spec (const_tree
attr.str = IDENTIFIER_POINTER (name);
attr.length = IDENTIFIER_LENGTH (name);
- extract_attribute_substring (&attr);
return attrs->attribute_hash->find_with_hash (&attr,
substring_hash (attr.str,
attr.length));
--- gcc/testsuite/c-c++-common/Wattributes-3.c.jj 2024-02-12
13:04:21.964502985 +0100
+++ gcc/testsuite/c-c++-common/Wattributes-3.c 2024-02-12 13:06:32.659688900
+0100
@@ -0,0 +1,13 @@
+/* PR c++/113674 */
+/* { dg-do compile { target { c || c++11 } } } */
+/* { dg-options "" } */
+
+[[____noreturn____]] int foo (int i) /* { dg-warning "'__noreturn__'
attribute (directive )?ignored" } */
+{
+ return i;
+}
+
+[[____maybe_unused____]] int bar (int i) /* { dg-warning "'__maybe_unused__'
attribute (directive )?ignored" } */
+{
+ return i;
+}
Jakub
