From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4BCC9D8D.10906@domain.hid> Date: Mon, 19 Apr 2010 20:14:37 +0200 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <4BCC619E.2@domain.hid> <4BCC6CEE.70907@domain.hid> <4BCC6E3C.3090301@domain.hid> <4BCC7092.1030809@domain.hid> <4BCC71AF.4030903@domain.hid> <4BCC77BD.9040900@domain.hid> <4BCC78D5.3010405@domain.hid> <4BCC7D88.4070403@domain.hid> <1271693411.16659.128.camel@domain.hid> <4BCC814C.6050003@domain.hid> <4BCC8484.1020108@domain.hid> <4BCC9107.1080605@domain.hid> <4BCC9247.10709@domain.hid> <4BCC9628.7030809@domain.hid> <4BCC9ADA.2020909@domain.hid> In-Reply-To: <4BCC9ADA.2020909@domain.hid> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Xenomai-core] [RFC] fix XENO_OPT_DEBUG bugs. List-Id: Xenomai life and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: xenomai-core Gilles Chanteperdrix wrote: > Jan Kiszka wrote: >> Gilles Chanteperdrix wrote: >>> Jan Kiszka wrote: >>>> Gilles Chanteperdrix wrote: >>>>> Jan Kiszka wrote: >>>>>> Philippe Gerum wrote: >>>>>>>>>> config XENO_OPT_DEBUG_FOO >>>>>>>>>> bool "..." >>>>>>>>>> >>>>>>>>>> config XENO_OPT_DEBUG_FOO_P >>>>>>>>>> int >>>>>>>>>> default "1" if XENO_OPT_DEBUG_FOO >>>>>>>>>> default "0" >>>>>>>>>> >>>>>>>>>> and XENO_DEBUG() could be extended to test for >>>>>>>>>> CONFIG_XENO_OPT_DEBUG_FOO_P when given "FOO". I'm just not sur= e if this >>>>>>>>>> can be expressed for legacy 2.4 kernels, so it might have to w= ait for >>>>>>>>>> Xenomai 3. >>>>>>> Well, actually, I would not merge this in Xenomai 3. I find this = rather >>>>>>> overkill; mainline first I mean, and mainline, i.e. the Xenomai c= ode >>>>>>> base only requires a simple and straightforward way to get debug >>>>>>> switches right. Having to make Kconfig a kitchen sink for some un= known >>>>>>> out of tree modules to be happy is not really my preferred approa= ch in >>>>>>> this particular case. >>>>>>> >>>>>>> Don't get me wrong, I'm not opposed to a more decentralized appro= ach on >>>>>>> the paper, it's just that I only care about the mainline tree her= e. >>>>>> The point is not out-of-tree but robustness. Neither the current >>>>>> decentralized #ifdef-#define nor its centralized brother meet this= >>>>>> criteria. An approach like the above which forces you to provide a= ll >>>>>> required bits before any of the cases (disabled/enabled) starts to= work >>>>>> does so. >>>>> Ok. What about: >>>>> >>>>> #define __name2(a, b) a ## b >>>>> #define name2(a, b) __name2(a, b) >>>>> >>>>> #define DECLARE_ASSERT_SYMBOL(sym) \ >>>>> static const int CONFIG_XENO_OPT_DEBUG_##sym##0 =3D 0, \ >>>>> __CONFIG_XENO_OPT_DEBUG_##sym =3D name2(CONFIG_XENO_OPT_DEBUG_##s= ym, 0) >>>>> >>>>> #define XENO_ASSERT(subsystem,cond,action) do { \ >>>>> if (unlikely(__CONFIG_XENO_OPT_DEBUG_##subsystem > 0 && !(cond)= )) { \ >>>>> xnarch_trace_panic_freeze(); \ >>>>> xnlogerr("assertion failed at %s:%d (%s)\n", __FILE__, __LI= NE__, (#cond)); \ >>>>> xnarch_trace_panic_dump(); \ >>>>> action; \ >>>>> } \ >>>>> } while(0) >>>>> >>>>> DECLARE_ASSERT_SYMBOL(NUCLEUS); >>>>> >>>>> It fails to compile when the debug symbol is set and >>>>> DECLARE_ASSERT_SYMBOL is missing, which plugs the failure of my pre= vious >>>>> attempt. >>>> I'm still wrapping my head around this. What would be the usage, >>>> >>>> #ifndef CONFIG_XENO_OPT_DEBUG_FOO >>>> #define CONFIG_XENO_OPT_DEBUG_FOO 0 >>>> #endif >>>> >>>> DECLARE_ASSERT_SYMBOL(FOO); >>>> >>>> ? If the compiler is smart enough to still drop the asserts based on= >>>> static const, I'm fine as this is an improvement. >>> No, you just use DECLARE_ASSERT_SYMBOL(FOO) >> Would be nice - if it worked. >> >>>> Still, IMHO, this solution would not even win the second league beau= ty >>>> contest (now it comes with as many additional lines as the >>>> Kconfig-approach). >>> Yes, it is not pretty but to add a config option you just add the usu= al >>> Kconfig stuff, then DECLARE_ASSERT_SYMBOL in the code instead of the >>> #ifndef #define foo 0 #endif. >>> >>> If you do not do it, you get a compilation error whether the option i= s >>> enabled or not. >>> >>> It can be decentralized, the find | grep mentioned earlier will still= work. >> If we can make it work like that, I'm all for it. But: >> >> error: initializer element is not constant >> (when disabled) >> >> or >> >> error: =E2=80=98y0=E2=80=99 undeclared here (not in a function) >> (when enabled) >> >> I'm afraid the preprocessor is not powerful enough for this task (we >> would need macros that include preprocessor conditionals). >=20 > The following seems to work for me: >=20 > #define __name2(a, b) a ## b > #define name2(a, b) __name2(a, b) >=20 > #define DECLARE_ASSERT_SYMBOL(sym) = \ > static const int CONFIG_XENO_OPT_DEBUG_##sym##0 =3D 0 >=20 > #define XENO_DEBUG(sym) (name2(CONFIG_XENO_OPT_DEBUG_##sym,0) > 0) >=20 > #define XENO_ASSERT(subsystem,cond,action) do { \ > if (unlikely(XENO_DEBUG(subsystem) && !(cond))) { \ > xnarch_trace_panic_freeze(); \ > xnlogerr("assertion failed at %s:%d (%s)\n", __FILE__, __LINE__= , (#cond)); \ > xnarch_trace_panic_dump(); \ > action; \ > } \ > } while(0) >=20 > DECLARE_ASSERT_SYMBOL(NUCLEUS); >=20 We only loose the detection of the debug symbol used and not declared if it is enabled. But this looks to me like a minor issue. Still trying thou= gh. --=20 Gilles.