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. GNU ld before 2015-10 had the behavior as well. 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 with -z start-stop-gc (LLD default) when -Wl,--gc-sections is used: ``` ld.lld: error: undefined symbol: __start___eap ``` The remain attribute will not be needed if the metadata sections are referenced by code directly. --- client/command.h | 12 +++++++----- client/dbus-proxy.h | 13 ++++++++----- src/eap-private.h | 6 +++++- src/module.h | 20 +++++++++++++------- 4 files changed, 33 insertions(+), 18 deletions(-) diff --git a/client/command.h b/client/command.h index d906dc9b..5d5df7fe 100644 --- a/client/command.h +++ b/client/command.h @@ -82,11 +82,13 @@ struct command_family_desc { void (*exit)(void); } __attribute__((aligned(8))); -#define COMMAND_FAMILY(name, init, exit) \ - static struct command_family_desc __command_family_ ## name \ - __attribute__((used, section("__command"), aligned(8))) = {\ - #name, init, exit \ - }; \ +#define COMMAND_FAMILY(name, init, exit) \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Wattributes\"") \ + static struct command_family_desc __command_family_##name \ + __attribute__((used, retain, section("__command"), aligned(8))) = { \ + #name, init, exit}; \ + _Pragma("GCC diagnostic pop") bool command_init(char **argv, int argc); void command_exit(void); diff --git a/client/dbus-proxy.h b/client/dbus-proxy.h index 6852a378..54e95746 100644 --- a/client/dbus-proxy.h +++ b/client/dbus-proxy.h @@ -117,11 +117,14 @@ struct interface_type_desc { void (*exit)(void); } __attribute__((aligned(8))); -#define INTERFACE_TYPE(interface, init, exit) \ - static struct interface_type_desc __interface_type_ ## interface\ - __attribute__((used, section("__interface"), aligned(8))) = {\ - #interface, init, exit \ - }; \ +#define INTERFACE_TYPE(interface, init, exit) \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Wattributes\"") \ + static struct interface_type_desc __interface_type_ ## interface \ + __attribute__((used, retain, section("__interface"), aligned(8))) = { \ + #interface, init, exit \ + }; \ + _Pragma("GCC diagnostic pop") bool dbus_proxy_init(void); bool dbus_proxy_exit(void); diff --git a/src/eap-private.h b/src/eap-private.h index 5121a330..1eef6bf4 100644 --- a/src/eap-private.h +++ b/src/eap-private.h @@ -94,10 +94,14 @@ struct eap_method_desc { } __attribute__((aligned(8))); #define EAP_METHOD_BUILTIN(name, init, exit) \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Wattributes\"") \ static struct eap_method_desc __eap_builtin_ ## name \ - __attribute__((used, section("__eap"), aligned(8))) = { \ + __attribute__((used, retain, section("__eap"), \ + aligned(8))) = { \ #name, init, exit \ }; \ + _Pragma("GCC diagnostic pop") int eap_register_method(struct eap_method *method); int eap_unregister_method(struct eap_method *method); diff --git a/src/module.h b/src/module.h index 8e1a9904..b4ec1284 100644 --- a/src/module.h +++ b/src/module.h @@ -33,19 +33,25 @@ struct iwd_module_depends { }; #define IWD_MODULE(name, init, exit) \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Wattributes\"") \ static struct iwd_module_desc __iwd_module_ ## name \ - __attribute__((used, section("__iwd_module"), aligned(8))) = {\ + __attribute__((used, retain, section("__iwd_module"), \ + aligned(8))) = { \ #name, init, exit \ - }; + }; \ + _Pragma("GCC diagnostic pop") #define IWD_MODULE_DEPENDS(name, dep) \ - static struct iwd_module_depends \ - __iwd_module__##name##_##dep \ - __attribute__((used, section("__iwd_module_dep"), \ - aligned(8))) = { \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Wattributes\"") \ + static struct iwd_module_depends __iwd_module__##name##_##dep \ + __attribute__((used, retain, \ + section("__iwd_module_dep"), aligned(8))) = { \ .self = #name, \ .target = #dep, \ - }; + }; \ + _Pragma("GCC diagnostic pop") int iwd_modules_init(void); void iwd_modules_exit(void); -- 2.34