On Thu, Dec 16, 2021 at 05:35:55PM -0500, Marek Polacek wrote:
> My patch to implement -Wno-attribute=A::b caused a bogus error when
> parsing
>
> [[foo::bar(1, 2)]];
>
> when -Wno-attributes=foo::bar was specified on the command line, because
> when we create a fake foo::bar attribute and insert it into our attribute
> table, it is created with max_length == 0 which doesn't allow any args.
> That is wrong -- we know nothing about the attribute, so we shouldn't
> require any specific number of arguments.
>
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
>
> PR c/103649
>
> gcc/ChangeLog:
>
> * attribs.c (handle_ignored_attributes_option): Create the fake
> attribute with max_length == -1.
>
> gcc/testsuite/ChangeLog:
>
> * c-c++-common/Wno-attributes-6.c: New test.
I'm afraid this still changes behavior. 0, -1 range attribute arguments
are parsed normally, while unknown attributes have the balanced token
sequence skipped.
E.g. the omp::{directive,sequence} attribute arguments are much more complex
than what the normal parsing can handle.
Can you make max -2 instead and special case it in the C and C++ FE
attribute handling and in a testcase try something that is a balanced token
sequence but not really valid when parsed as ordinary attributes' arguments?
> --- a/gcc/attribs.c
> +++ b/gcc/attribs.c
> @@ -304,7 +304,7 @@ handle_ignored_attributes_option (vec<char *> *v)
> We can't free it here, so squirrel away the pointers. */
> attribute_spec *table = new attribute_spec[2];
> ignored_attributes_table.safe_push (table);
> - table[0] = { attr, 0, 0, false, false, false, false, nullptr, nullptr
> };
> + table[0] = { attr, 0, -1, false, false, false, false, nullptr, nullptr
> };
> table[1] = { nullptr, 0, 0, false, false, false, false, nullptr,
> nullptr };
> register_scoped_attributes (table, IDENTIFIER_POINTER (vendor_id),
> !attr);
> diff --git a/gcc/testsuite/c-c++-common/Wno-attributes-6.c
> b/gcc/testsuite/c-c++-common/Wno-attributes-6.c
> new file mode 100644
> index 00000000000..02cdaaa1e89
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/Wno-attributes-6.c
> @@ -0,0 +1,9 @@
> +/* PR c/103649 */
> +/* { dg-do compile { target { c || c++11 } } } */
> +/* { dg-additional-options "-Wno-attributes=foo::bar" } */
> +/* { dg-additional-options "-Wno-attributes=baz::" } */
> +
> +[[foo::bar(1, 2)]]; /* { dg-warning "attribute ignored" } */
> +[[baz::bar(1, 2)]]; /* { dg-warning "attribute ignored" } */
> +[[foo::bar(1, 2)]] void f1();
> +[[baz::bar(1, 2)]] void f2();
>
> base-commit: f91814c22595e1db642140efe030caf2c092ab6f
> --
> 2.33.1
Jakub
