LLD 13 and GNU ld 2.37 support -z start-stop-gc which allows garbage collection of C identifier name sections despite the __start_/__stop_ references. Simply set the retain attribute so that GCC 11 (if configure-time binutils is 2.36 or newer)/Clang 13 will set the SHF_GNU_RETAIN section attribute to prevent garbage collection.
Without the patch, there are linker errors like the following with -z start-stop-gc: ld.lld: error: undefined symbol: __stop___cmd
referenced by iw.c:418 iw.o:(__handle_cmd)
Suggested-by: Fangrui Song maskray@google.com
Cc: stable@vger.kernel.org
Signed-off-by: Manoj Gupta manojgupta@google.com --- iw.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/iw.h b/iw.h index 7f7f4fc..67aa00c 100644 --- a/iw.h +++ b/iw.h @@ -118,8 +118,9 @@ struct chandef { .parent = _section, \ .selector = (_sel), \ }; \ + _Pragma("GCC diagnostic ignored "-Wattributes"") \ static struct cmd *__cmd ## _ ## _symname ## _ ## _handler ## _ ## _nlcmd ## _ ## _idby ## _ ## _hidden ## _p \ - __attribute__((used,section("__cmd"))) = \ + __attribute__((used,retain,section("__cmd"))) = \ &__cmd ## _ ## _symname ## _ ## _handler ## _ ## _nlcmd ## _ ## _idby ## _ ## _hidden #define __ACMD(_section, _symname, _name, _args, _nlcmd, _flags, _hidden, _idby, _handler, _help, _sel, _alias)\ __COMMAND(_section, _symname, _name, _args, _nlcmd, _flags, _hidden, _idby, _handler, _help, _sel);\