Re: [RFC] fix semicolon at the end of RTE_LOG_REGISTER_DEFAULT

[Stephen Hemminger <stephen@networkplumber.org>]

On Sat, 20 Apr 2024 09:48:24 +0200
Morten Brørup <mb@smartsharesystems.com> wrote:

> > From: Stephen Hemminger [mailto:stephen@networkplumber.org]
> > Sent: Saturday, 20 April 2024 02.08
> > 
> > The macro RTE_LOG_REGISTER_DEFAULT emits code for an initialization
> > function. If a driver (and most do) adds a semicolon after the macro.
> > 
> > RTE_LOG_REGISTER_DEFAULT(logtype_foo, INFO);
> > 
> > Is equivalent to:
> > 
> > 	int logtype_foo;
> > 	static void __logtype_foo(void) {
> > 	    logtype_foo = rte_log_register_type_and_pick_level(name,
> > 	                  	 RTE_LOG_INFO);
> > 		if (type < 0)
> > 			logtype_foo = RTE_LOGTYPE_EAL;
> > 	};
> > The problem is that extra semi-colon after the function.
> > 
> > If code is built with highest level of warnings (pedantic),
> > then it will generate a warning.
> >   warning: ISO C does not allow extra ‘;’ outside of a function
> > 
> > This is a treewide fix for this.  
> 
> It seems weird omitting the semicolon when using this macro.
> 
> How about using the same trick as RTE_INIT_PRIO():
> 
> #define RTE_INIT_PRIO(name, priority) \
> 	static void name(void); \
> 	static int __cdecl name ## _thunk(void) { name(); return 0; } \
> 	__pragma(const_seg(CTOR_PRIORITY_TO_SECTION(priority))) \
> 	__declspec(allocate(CTOR_PRIORITY_TO_SECTION(priority))) \
> 	    _PIFV name ## _pointer = &name ## _thunk; \
> 	__pragma(const_seg()) \
> 	static void name(void)


RTE_INIT_PRIO is what is causing the problem. My example comes from:
   RTE_LOG_REGISTER_DEFAULT() -> RTE_LOG_REGISTER_IMPL() -> RTE_INIT -> RTE_INIT_PRIO

The last line is used as prefix before RTE_LOG_REGISTER_IMPL that defines
the init function full expansion is:

// from RTE_LOG_REGISTER_IMPL
int logtype_foo;
// from RTE_INIT_PRIO
static void __logtype_foo(void);
static int __cdecl __logtype_foo_thunk(void) { __logtype_foo(); return 0; }
__pragma(const_seg(CTOR_PRIORITY_TO_SECTION(priority)))
__declspec(allocate(CTOR_PRIORITY_TO_SECTION(priority)))
    _PIFV __logtype_foo ## _pointer = &__logtype_foo_thunk;
__pragma(const_seg())
static void __logtype_foo(void)
// from RTE_LOG_REGISTER_IMPL
	logtype_foo = rte_log_register_logtype_foo_and_pick_level(__logtype_foo, RTE_LOG_##level);
	if (logtype_foo < 0)
		logtype_foo = RTE_LOGLOGTYPE_FOO_EAL;
}  // no ; here is allowed