[PATCH] linker_lists.h: Add attribute used to ll_entry_start macro

[appujee]

> So, saying "unused" and then "used" doesn't seem to make any sense.
unused and used attributes do not cancel each other. They have different
semantics. I agree this part of the code needs some attention. zero sized
arrays are not C compliant as I understand it, even more so when it is
declared outside of a struct.

On Wed, Mar 22, 2023 at 4:58 PM Tom Rini <trini at konsulko.com> wrote:

> On Tue, Feb 21, 2023 at 03:33:20PM -0800, Aditya Kumar wrote:
>
> > The variable gets dropped by clang compiler in an optimized builds.
> > Adding attribute((used)) allows the symbol to be preserved. Similar
> > changes have been proposed in the past e.g.,
> > 569524741a01e1a96fc2b75dd7e5d12e41ce6c2b for ll_entry_declare macro.
> >
> > Signed-off-by: AdityaK <appujee at google.com>
> > Reviewed-by: Simon Glass <sjg at chromium.org>
> > ---
> >  include/linker_lists.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/linker_lists.h b/include/linker_lists.h
> > index d3da9d44e8..4cd13c3bc8 100644
> > --- a/include/linker_lists.h
> > +++ b/include/linker_lists.h
> > @@ -125,7 +125,7 @@
> >  #define ll_entry_start(_type, _list) \
> >  ({ \
> >   static char start[0] __aligned(CONFIG_LINKER_LIST_ALIGN) \
> > - __attribute__((unused)) \
> > + __attribute__((unused)) __attribute__((used)) \
> >   __section("__u_boot_list_2_"#_list"_1"); \
> >   (_type *)&start; \
> >  })
>
> So, saying "unused" and then "used" doesn't seem to make any sense. And
> given some other problems we see with newer clang, which Simon reports
> this patch doesn't fully fix, we probably need to give that area a good
> going over to see what attributes do and don't make sense, really.
>
> --
> Tom
>